1: Radiat Res. 2005 Oct;164(4 Pt 1):369-82. Low-dose irradiation alters the transcript profiles of human lymphoblastoid cells including genes associated with cytogenetic radioadaptive response. Coleman MA, Yin E, Peterson LE, Nelson D, Sorensen K, Tucker JD, Wyrobek AJ. Biology and Biotechnology Research Program, Lawrence Livermore, National Laboratory, Livermore, California 94551, USA. Low-dose ionizing radiation alters the gene expression profiles of mammalian cells, yet there is little understanding of the underlying cellular mechanisms responsible for these changes or of their consequences for genomic stability. We investigated the cytogenetic adaptive response of human lymphoblastoid cell lines exposed to 5 cGy (priming dose) followed by 2 Gy (challenge dose) compared to cells that received a single 2-Gy dose to (a) determine how the priming dose influences subsequent gene transcript expression in reproducibly adapting and non-adapting cell lines, and (b) identify gene transcripts that are associated with reductions in the magnitude of chromosomal damage after the challenge dose. The transcript profiles were evaluated using oligonucleotide arrays and RNA obtained 4 h after the challenge dose. A set of 145 genes (false discovery rate = 5%) with transcripts that were affected by the 5-cGy priming dose fell into two categories: (a) a set of common genes that were similarly modulated by the 5-cGy priming dose irrespective of whether the cells subsequently adapted or not and (b) genes with differential transcription in accordance with the cell lines that showed either adaptive or non-adaptive outcomes. The common priming-dose response genes showed up-regulation for protein synthesis genes and down-regulation of metabolic and signal transduction genes (>10-fold differences). The genes associated with subsequent adaptive and non-adaptive outcomes involved DNA repair, stress response, cell cycle control and apoptosis. Our findings support the importance of TP53-related functions in the control of the low-dose cytogenetic radioadaptive response and suggest that certain low-dose-induced alterations in cellular functions are predictive for the risk of subsequent genomic damage. PMID: 16187739 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 2: Chin Med J (Engl). 2005 Aug 20;118(16):1330-7. Experimental study on anti-neoplastic activity of epigallocatechin-3-gallate to digestive tract carcinomas. Ran ZH, Zou J, Xiao SD. Shanghai Institute of Digestive Diseases, Renji Hospital, Shanghai Second Medical University, Shanghai 200001, China. z-ran@online.sh.cn BACKGROUND: Epigallocatechin-3-gallate (EGCG) has been demonstrated to have anti-neoplastic activity, but the effective concentration of EGCG and its possible mechanisms are uncertain. The study on the killing effects of EGCG on different digestive tract cancer cell lines can find target sites of its anti-neoplastic effect and provide a theoretical basis for its clinical application in the treatment of cancers. METHODS: Methyl thiazolyl tetrazolium (MTT) analysis was made to detect the differential sensitivities of eight digestive tract cancer cell lines to EGCG. The effect of EGCG on cell cycle distribution of sensitive cancer cell line was measured by flow cytometry. By polymerase chain reaction (PCR)-enzyme linked immunosorbent assay (ELISA) protocol, the influence of EGCG on telomerase activity of sensitive cancer cell line was also investigated. RT-PCR method was employed to detect the influence of EGCG on the expressions of hTERT, c-myc, p53 and mad1 genes in sensitive cancer cell line. RESULTS: EGCG exhibited dose-dependent killing effects on all eight digestive tract cancer cell lines. The 50% inhibitory concentration (IC50) of SW1116, MKN45, BGC823, SGC7901, AGS, MKN28, HGC27 and LoVo cells were 51.7 micromol/L, 55.9 micromol/L, 68.5 micromol/L, 79.1 micromol/L, 83.8 micromol/L, 119.8 micromol/L, 183.2 micromol/L and 194.6 micromol/L, respectively. There were no apparent changes in cell cycle distribution of sensitive cancer cell line MKN45 48 hours after incubating with three different concentrations of EGCG compared with the controls. It was found that EGCG could suppress the telomerase activity of MKN45 cells, and the effects were dose- and time-dependent. After EGCG administration, the expression of hTERT and c-myc genes in MKN45 cells was decreased, that of the mad1 gene increased, and that of the p53 gene unchanged. CONCLUSIONS: EGCG has dose-dependent killing effects on different digestive tract cancer cell lines. Administration of EGCG has no obvious effect on cell cycle distribution of sensitive cancer cell line MKN45. The anti-neoplastic activity of EGCG might be due to the inhibition of telomerase activity by means of its influence on hTERT and the up-stream regulation genes. PMID: 16157026 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 3: Orv Hetil. 2005 Aug 7;146(32):1673-82. [Molecular genetic methods for the prognostic criteria in multiple myeloma] [Article in Hungarian] Mikala G, Jako J, Valyi-Nagy I. Hematologiai es Haemostasis Osztaly. Routine cytogenetic and molecular genetic analysis of plasma cell malignancies, such as multiple myeloma, became widespread only recently. As the result of these investigations, it became clear that tumor cell karyotype is fundamental from the viewpoint of therapy selection and prognosis. It is worthwhile to distinguish hyperdiploid and nonhyperdiploid myeloma, while five separate prognostic groups (TCI-5) may be identified on the basis of immunoglobulin gene translocations and cyclin expression. Deletion of the q arm of chromosome 13 or amplification of region 1q21 (and the CKS1B gene) can identify further subgroups of poor prognosis and few therapeutic options. Meanwhile, tumors harboring translocation t(11;14) respond favorably to conventional chemotherapy and exhibit exceptionally good and long-lasting response to high-dose chemotherapy. Progression of the disease may coincide with complex translocations of the c-myc gene or deletions involving the p53 tumor-suppressor gene, spreading of ras-mutations. These events represent clonal evolution at great tumor cell mass and advanced disease, therefore, are only of secondary prognostic significance. Publication Types: Review Review, Tutorial PMID: 16149245 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 4: Biochem Biophys Res Commun. 2005 Oct 7;335(4):1272-9. Transcriptional repression of the eukaryotic initiation factor 4E gene by wild type p53. Zhu N, Gu L, Findley HW, Zhou M. Division of Pediatric Hematology/Oncology/BMT, Emory University School of Medicine, Atlanta, GA, USA. The eukaryotic initiation factor 4E (eIF4E) plays important roles in transformation and cancer progression. It is frequently overexpressed in malignant cells, one mechanism of which is through transcriptional activation by c-myc. Here, we report that high level of eIF4E expression and its tumorigenicity could be alternatively associated with defects of p53, since we found that induction of wt-p53 repressed eIF4E expression. Gene transfection of p53 inhibited eIF4E promoter activity, while inactivation of p53 either by mutation or by over-expression of MDM2 resulted in stimulation of eIF4E promoter activity. We demonstrated that p53-repression of eIF4E was regulated by c-myc. The wt-p53 can physically bind to c-myc, which inhibited binding of c-myc to eIF4E promoter and c-myc-stimulated promoter activity. These results suggest that the expression of eIF4E is reciprocally regulated by p53 and c-myc, and loss of p53-mediated control over c-myc-dependent transactivation of eIF4E may represent a novel mechanism for eIF4E-mediated neoplastic transformation and cancer progression. PMID: 16112647 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 5: Mol Cell Biol. 2005 Sep;25(17):7423-31. p53-Dependent transcriptional repression of c-myc is required for G1 cell cycle arrest. Ho JS, Ma W, Mao DY, Benchimol S. Ontario Cancer Institute, Prince Margaret Hospital, Toronto, Canada. The ability of p53 to promote apoptosis and cell cycle arrest is believed to be important for its tumor suppression function. Besides activating the expression of cell cycle arrest and proapoptotic genes, p53 also represses a number of genes. Previous studies have shown an association between p53 activation and down-regulation of c-myc expression. However, the mechanism and physiological significance of p53-mediated c-myc repression remain unclear. Here, we show that c-myc is repressed in a p53-dependent manner in various mouse and human cell lines and mouse tissues. Furthermore, c-myc repression is not dependent on the expression of p21(WAF1). Abrogating the repression of c-myc by ectopic c-myc expression interferes with the ability of p53 to induce G(1) cell cycle arrest and differentiation but enhances the ability of p53 to promote apoptosis. We propose that p53-dependent cell cycle arrest is dependent not only on the transactivation of cell cycle arrest genes but also on the transrepression of c-myc. Chromatin immunoprecipitation assays indicate that p53 is bound to the c-myc promoter in vivo. We report that trichostatin A, an inhibitor of histone deacetylases, abrogates the ability of p53 to repress c-myc transcription. We also show that p53-mediated transcriptional repression of c-myc is accompanied by a decrease in the level of acetylated histone H4 at the c-myc promoter and by recruitment of the corepressor mSin3a. These data suggest that p53 represses c-myc transcription through a mechanism that involves histone deacetylation. PMID: 16107691 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 6: Nature. 2005 Aug 11;436(7052):807-11. Comment in: Nature. 2005 Aug 11;436(7052):787-9. Evasion of the p53 tumour surveillance network by tumour-derived MYC mutants. Hemann MT, Bric A, Teruya-Feldstein J, Herbst A, Nilsson JA, Cordon-Cardo C, Cleveland JL, Tansey WP, Lowe SW. Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA. The c-Myc oncoprotein promotes proliferation and apoptosis, such that mutations that disable apoptotic programmes often cooperate with MYC during tumorigenesis. Here we report that two common mutant MYC alleles derived from human Burkitt's lymphoma uncouple proliferation from apoptosis and, as a result, are more effective than wild-type MYC at promoting B cell lymphomagenesis in mice. Mutant MYC proteins retain their ability to stimulate proliferation and activate p53, but are defective at promoting apoptosis due to a failure to induce the BH3-only protein Bim (a member of the B cell lymphoma 2 (Bcl2) family) and effectively inhibit Bcl2. Disruption of apoptosis through enforced expression of Bcl2, or loss of either Bim or p53 function, enables wild-type MYC to produce lymphomas as efficiently as mutant MYC. These data show how parallel apoptotic pathways act together to suppress MYC-induced transformation, and how mutant MYC proteins, by selectively disabling a p53-independent pathway, enable tumour cells to evade p53 action during lymphomagenesis. PMID: 16094360 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 7: Nature. 2005 Aug 11;436(7052):787-9. Comment on: Nature. 2005 Aug 11;436(7052):807-11. Cancer: two in one. Berns A. Publication Types: Comment News PMID: 16094355 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 8: Mol Cancer. 2005 Aug 5;4:28. Tumor suppressor in lung cancer 1 (TSLC1) alters tumorigenic growth properties and gene expression. Sussan TE, Pletcher MT, Murakami Y, Reeves RH. Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185, USA. tsussan@jhmi.edu BACKGROUND: Introduction of cDNA or genomic clones of the tumor suppressor in lung cancer 1 (TSLC1) gene into the non-small cell lung cancer line, A549, reverses tumorigenic growth properties of these cells. These results and the observation that TSLC1 is down-regulated in a number of tumors suggest that TSLC1 functions as a critical switch mediating repression of tumorigenesis. RESULTS: To investigate this mechanism, we compared growth properties of A549 with the TSLC1-containing derivative. We found a G1/S phase transition delay in 12.2. Subtractive hybridization, quantitative PCR, and TranSignal Protein/DNA arrays were used to identify genes whose expression changed when TSLC1 was up-regulated. Members of common G1/S phase regulatory pathways such as TP53, MYC, RB1 and HRAS were not differentially expressed, indicating that TSLC1 may function through an alternative pathway(s). A number of genes involved in cell proliferation and tumorigenesis were differentially expressed, notably genes in the Ras-induced senescence pathway. We examined expression of several of these key genes in human tumors and normal lung tissue, and found similar changes in expression, validating the physiological relevance of the A549 and 12.2 cell lines. CONCLUSION: Gene expression and cell cycle differences provide insights into potential downstream pathways of TSLC1 that mediate the suppression of tumor properties in A549 cells. PMID: 16083501 [PubMed - in process] --------------------------------------------------------------- 9: J Cell Biol. 2005 Aug 1;170(3):367-78. Epub 2005 Jul 25. Mammalian WDR12 is a novel member of the Pes1-Bop1 complex and is required for ribosome biogenesis and cell proliferation. Holzel M, Rohrmoser M, Schlee M, Grimm T, Harasim T, Malamoussi A, Gruber-Eber A, Kremmer E, Hiddemann W, Bornkamm GW, Eick D. Institute of Clinical Molecular Biology and Tumour Genetics, National Research Center for Environment and Health (GSF), 81377 Munich, Germany. Target genes of the protooncogene c-myc are implicated in cell cycle and growth control, yet the linkage of both is still unexplored. Here, we show that the products of the nucleolar target genes Pes1 and Bop1 form a stable complex with a novel member, WDR12 (PeBoW complex). Endogenous WDR12, a WD40 repeat protein, is crucial for processing of the 32S precursor ribosomal RNA (rRNA) and cell proliferation. Further, a conditionally expressed dominant-negative mutant of WDR12 also blocks rRNA processing and induces a reversible cell cycle arrest. Mutant WDR12 triggers accumulation of p53 in a p19ARF-independent manner in proliferating cells but not in quiescent cells. Interestingly, a potential homologous complex of Pes1-Bop1-WDR12 in yeast (Nop7p-Erb1p-Ytm1p) is involved in the control of ribosome biogenesis and S phase entry. In conclusion, the integrity of the PeBoW complex is required for ribosome biogenesis and cell proliferation in mammalian cells. PMID: 16043514 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 10: Acta Ophthalmol Scand. 2005 Aug;83(4):471-6. Age-related differential expression of apoptosis-related genes in conjunctival epithelial cells. Giebel J, Woenckhaus C, Fabian M, Tost F. Institute of Anatomy, Ernst Moritz Arndt University, Greifswald, Germany. PURPOSE: To investigate whether the expression of apoptosis-related genes in normal conjunctival epithelial cells is age-related (as a prerequisite to assessing whether dysregulation of apoptosis may be involved during degenerative diseases). METHODS: Differential expression of apoptosis-related genes (e.g. apoptosis protease-activating factor 1 [Apaf-1]; caspases [casp] 3, 5, 8 and 9; Bad, Bax, Bcl-2, Bim, c-myc, Bag-1, as well as p53) was assessed by reverse transcription-polymerase chain reaction (RT-PCR). Samples were obtained from impression cytology (IC) specimens taken from 50 healthy subjects. Group A comprised 27 subjects aged 19-32 years and group B included 23 subjects aged 53-84 years. RESULTS: Reverse transcription-PCR revealed the detection of apoptosis-related m-RNAs as follows (group A compared to group B): Apaf-1 0%/0%; Bcl-2 0%/35%; Bim 0%/9%; Bag-1 0%/9%; p53 0%/4%; casp-3 11%/52%; casp-5 59%/48%; casp-8 44%/22%; casp-9 4%/9%; Bax 81%/52%; Bad 96%/56%, and c-myc 89%/96%. CONCLUSION: The data show an age-related expression of apoptosis-related genes such as casp-3, Bad, Bax and Bcl-2 in normal conjunctival cells. These results provide basic information which will help us understand the expression pattern of apoptotic genes during physiological ageing of the conjunctiva and the possible dysregulation of apoptotic genes during acute and chronic diseases such as dry eye disease, allergic conjunctivitis or cicatrizing conjunctivitis. PMID: 16029273 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 11: Mol Cell Biol. 2005 Aug;25(15):6464-74. Transformation of human and murine fibroblasts without viral oncoproteins. Boehm JS, Hession MT, Bulmer SE, Hahn WC. Department of Medical Oncology, Dana-Farber Cancer Institute, 44 Binney St., Dana 710C, Boston, MA 02115-6013, USA. Murine embryo fibroblasts are readily transformed by the introduction of specific combinations of oncogenes; however, the expression of those same oncogenes in human cells fails to convert such cells to tumorigenicity. Using normal human and murine embryonic fibroblasts, we show that the transformation of human cells requires several additional alterations beyond those required to transform comparable murine cells. The introduction of the c-Myc and H-RAS oncogenes in the setting of loss of p53 function efficiently transforms murine embryo fibroblasts but fails to transform human cells constitutively expressing hTERT, the catalytic subunit of telomerase. In contrast, transformation of multiple strains of human fibroblasts requires the constitutive expression of c-Myc, H-RAS, and hTERT, together with loss of function of the p53, RB, and PTEN tumor suppressor genes. These manipulations permit the development of transformed human fibroblasts with genetic alterations similar to those found associated with human cancers and define specific differences in the susceptibility of human and murine fibroblasts to experimental transformation. PMID: 16024784 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 12: Exp Mol Pathol. 2005 Aug;79(1):42-50. Epub 2005 Apr 7. Expression of c-myc, erbB-2, p53 and nm23-H1 gene product in benign and malignant breast lesions: coexpression and correlation with clinicopathologic parameters. Sirotkovic-Skerlev M, Krizanac S, Kapitanovic S, Husnjak K, Unusic J, Pavelic K. Department of Pathophysiology, Zagreb University Hospital and Zagreb University Medical School, Kispaticeva 12, HR-10000 Zagreb, Croatia. majas@irb.hr The aims of this study were to assess the expression of protein products of c-myc, erbB-2, p53 and nm23-H1 gene in benign and malignant breast lesions, to estimate their possible coexpression and to correlate the results of immunohistochemical analysis with various clinicopathologic parameters. The method used was the immunohistochemical detection of the corresponding protein. Expression of c-myc protein was high in both malignant and benign lesions (95% and 100%). Expression of erbB-2 and mutated p53 proteins in malignant lesions was 27% and 34%. These proteins were present in benign lesions as well: 7.8% of benign lesions were positive for erbB-2 protein and 19.6% for p53 protein. The expression of nm23-H1 protein was similar in benign and malignant lesions: 47% and 54%. The coexpression of nm23-H1 and mutated p53 protein was found in 14 carcinomas (16.5%). We found a tendency of negative correlation between the expression of these two proteins. We also found a negative correlation between the size of breast carcinomas and the expression of nm23-H1, a higher proportion of nm23-H1-positive carcinomas in the group of erbB-2-negative, p53-negative carcinomas and a higher proportion of nm23-H1-positive carcinomas in the group of malignant lesions with negative axillary lymph nodes. Our results support the hypothesis that in women with breast cancer the expression of nm23-H1 gene may contribute to more favorable phenotype. We also showed that some changes found in malignant breast tumors such as the presence of mutated p53 protein and the expression of erbB-2 protein may be found in benign lesions as well. PMID: 16005711 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 13: Biochem Biophys Res Commun. 2005 Aug 26;334(2):386-94. ARF and ATM/ATR cooperate in p53-mediated apoptosis upon oncogenic stress. Pauklin S, Kristjuhan A, Maimets T, Jaks V. Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia Street, Tartu 51010, Estonia. spauklin@ut.ee Induction of apoptosis is pivotal for eliminating cells with damaged DNA or deregulated proliferation. We show that tumor suppressor ARF and ATM/ATR kinase pathways cooperate in the induction of apoptosis in response to elevated expression of c-myc, beta-catenin or human papilloma virus E7 oncogenes. Overexpression of oncogenes leads to the formation of phosphorylated H2AX foci, induction of Rad51 protein levels and ATM/ATR-dependent phosphorylation of p53. Inhibition of ATM/ATR kinases abolishes both induction of Rad51 and phosphorylation of p53, and remarkably reduces the level of apoptosis induced by co-expression of oncogenes and ARF. However, the induction of apoptosis is downregulated in p53-/- cells and does not depend on activities of ATM/ATR kinases, indicating that efficient induction of apoptosis by oncogene activation depends on coordinated action of ARF and ATM/ATR pathways in the regulation of p53. PMID: 16004968 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 14: Cell Death Differ. 2005 Oct;12(10):1319-28. MIF loss impairs Myc-induced lymphomagenesis. Talos F, Mena P, Fingerle-Rowson G, Moll U, Petrenko O. Department of Pathology, State University of New York at Stony Brook, Stony Brook, NY 11794, USA. Macrophage migration inhibitory factor (MIF) is a potent regulator of inflammation and cell growth. Using the Emu-Myc lymphoma mouse model, we demonstrate that loss of MIF markedly delays the onset of B-cell lymphoma development in vivo. The molecular basis for this MIF-loss-induced phenotype is the perturbed DNA-binding activity of E2F factors and the concomitantly enhanced tumor suppressor activity of the p53 pathway. Accordingly, premalignant MIF-null Emu-Myc B-cells are predisposed to delayed S-phase progression and increased apoptosis. MIF-deficient lymphomas that do arise under these conditions contain frequent ARF deletions and p53 inactivating mutations. Conversely, MIF expression is retained in tumors developed by wild-type Emu-Myc animals, and the presence of one or both MIF alleles is sufficient to accelerate the development of Myc-induced lymphomas. Collectively, these results indicate that MIF promotes Myc-mediated tumorigenesis, at least in the B-lymphoid compartment, and implicate MIF as a mediator of malignant cell growth in vivo. PMID: 15947793 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 15: J Ethnopharmacol. 2005 Aug 22;100(1-2):187-92. Inhibition of human endothelial cell proliferation by Gami--Jeonggi--San (Jiawei--Zhenqi--San) is accompanied by transcriptional up-regulation of p53 and Waf1 tumor suppressor genes. Moon SK, Jin HS, Ko CN, Kim YS, Bae HS, Lee KS, Cho KH. Department of Circulatory Internal Medicine, College of Oriental Medicine, Kyung Hee University, Seoul 130-702, Republic of Korea. The effects of Gami-Jeonggi-San (GJS) on proliferation of human endothelial cell (HUV-EC-C) were investigated using a flow cytometry and a quantitative RT-PCR analysis of gene expression. An accumulation of cells at G(1) phase of the cell cycle was found at 72 h after treatment (10 microl/ml) while no detectable reduction of PCNA expression was recognized. To elucidate that the cell cycle inhibitory effect of GJS stems from its capability of transcriptional regulation of the cell cycle-controlling genes, we investigated mRNA expression of p53, Waf1, PCNA, Cyclin D1, Cdc2, Histone H3, c-Myc, and c-Fos. Significantly elevated mRNA levels of the p53 tumor suppressor gene and its down-stream mediator gene, Waf1, whose increased expressions were known to trigger G(1) cell cycle arrest, were observed. In contrast, a marked reduction of two early G(1)-specific, cell cycle stimulating genes, c-Myc and c-Fos, were found at 24h after treatment, while there were no detectable changes in expressions of G(1)-S or G(2)-M transition-related genes, indicating the G(1) specificity of GJS effect on the cell cycle. These results suggest that the pharmacological effects of GJS might be derived in part from inhibition of cellular proliferation of human endothelial cells, and that GJS inhibition of the cell cycle might stem from its regulatory capability on the transcription of the cell cycle-controlling genes, including p53 and Waf1 tumor suppressor genes. PMID: 15941636 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 16: Apoptosis. 2005 May;10(3):503-12. Disease-associated fibronectin matrix fragments trigger anoikis of human primary ligament cells: p53 and c-myc are suppressed. Dai R, Iwama A, Wang S, Kapila YL. Department of Stomatology, School of Dentistry, University of California, San Francisco, CA 94143-0512, USA. Inflammation in periodontal disease is characterized by the breakdown of the extracellular matrix. This study shows that an inflammation-associated matrix breakdown fragment of fibronectin (FN) induces anoikis of human periodontal ligament (PDL) cells. This 40 kDa fragment was identified in human inflammatory crevicular fluid and is associated with disease status. Previously, we reported that a similar recombinant FN fragment triggered apoptosis of PDL cells by an alternate apoptotic signaling pathway that requires transcriptional downregulation of p53 and c-myc. Thus, to determine whether the physiologically relevant 40 kDa fragment triggers apoptosis in these cells, the 40 kDa fragment was generated and studied for its apoptotic properties. The 40 kDa fragment induces apoptosis of PDL cells, and preincubation of cells with intact vitronectin, FN, and to a limited extent collagen I, rescue this apoptotic phenotype. These data suggest that the 40 kDa fragment prevents PDL cell spreading, thereby inducing anoikis. The signaling pathway also involves a downregulation in p53 and c-myc, as determined by Western blotting and real time quantitative PCR. These data indicate that an altered FN matrix as is elaborated in inflammation induces anoikis of resident cells and thus may contribute to disease progression. PMID: 15909113 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 17: Cancer Detect Prev. 2005;29(3):241-8. Autoimmune response to anti-apoptotic protein survivin and its association with antibodies to p53 and c-myc in cancer detection. Megliorino R, Shi FD, Peng XX, Wang X, Chan EK, Tan EM, Zhang JY. Department of Biological Sciences, The University of Texas, El Paso, TX, USA. Survivin, an inhibitor of apoptotic protein, is over-expressed in many cancers but not in normal differentiated adult tissues. Recently, antibodies to survivin have been demonstrated in patients with lung and colorectal cancer. Whether antibodies to survivin can be used as a marker for the diagnosis of cancer, and how antibody to survivin is related to antibodies against tumor suppressor protein p53 and oncoprotein c-myc remains to be evaluated. In the present study, the full-length recombinant proteins survivin, p53 and c-myc, were expressed and used as antigens in enzyme-linked immunosorbent assay (ELISA) and Western blot for the detection of antibodies to these three proteins. Sera from 1137 patients with 11 different types of cancer were analyzed. Antibodies to survivin were detected in 8.4% (96/1137), with a significant difference from the control groups consisting of normal individuals and autoimmune disease patients (p<0.05). Of 1137 cancer sera, 546 were also tested for the presence of antibodies to p53 and c-myc. Frequencies of antibodies to p53 and c-myc were 11.5 and 12.3%, respectively. Although antibodies to either one of three antigens do not reach levels of sensitivity, which could become routinely useful in diagnosis, it appears that there are different patterns of antibody frequency in individual cancer type. The results also indicated that when the presence of antibody to any one of these three antigens was considered, the cumulative frequency was increased to 27.3% (149/546) for the total group of cancer patients. It became apparent from our data that the combination of antibodies might acquire higher sensitivity. PMID: 15896923 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 18: Cancer Biother Radiopharm. 2005 Apr;20(2):173-80. Studies on inducing apoptosis effects and mechanism of CIK cells for MGC-803 gastric cancer cell lines. Sun S, Li XM, Li XD, Yang WS. Department of Pathology, Yanbian University, College of Medicine, Yanji 133000, Jilin Province, China. sunshu_yxy@sina.com The induction of apoptosis and antiproliferation effect of cytokine-induced killer cells (CIK cells) on MGC- 803 cells and its mechanisms were studied by using a tetrazolium dye-based (MTT) assay. Morphological changes were observed by using inverted microscope, haematoxylin/eosin (HE) staining, scanning electron microscope, and transmission electron microscope. The TdT-mediated dUTP nick and labeling (TUNEL) method was used to detect the apoptosis-induced by CIK cells. The expression rate of p53, p16, C-myc, Bcl-2, and Bax proteins were studied by using immunohistochemical staining. There were significant differences according to varied effector-target ratios at the same working time (p < 0.01) and the same effector-target ratios at different working times (p < 0.01). Inverted microscope and HE staining observation showed that CIK cells were closer to the target cells and formed a typical "rose" shape. The scanning electron microscope showed that most target cells had undergone apoptosis and many "apoptotic bodies," and that transmission electron microscopy showed condensed chromatin, disintegration of the nucleolus, vacuoles in the cytoplasm, and apoptotic bodies appearing in most target cells. TUNEL analysis showed that apoptotic cells contract and turn navy blue in nuclei or perinuclei in the experimental group. The apoptotic rate was upmodulated between 5 and 14 hours and downregulated between 14 and 24 hours in the "CIK" experimental group. The expression of p53, p16, C-myc, and Bcl-2 were significantly downregulated (p < 0.01), and the expression of Bax was upregulated over the time of coculture in the "CIK" experimental group, compared to the control group. Our studies suggested that CIK cells induce apoptosis and have an antiproliferative effect on human MGC-803 gastric cancer cells. The CIK cells kill MGC-803 gastric cancer cells by inducing apoptosis in the early stage and by inducing necrosis in the late stage through the downregulating expression of p53, C-myc, and Bcl-2 and the upregulating expression of Bax. PMID: 15869451 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 19: J Clin Oncol. 2005 Jun 1;23(16):3780-92. Epub 2005 May 2. Evidence for distinct pathomechanisms in genetic subgroups of chronic lymphocytic leukemia revealed by quantitative expression analysis of cell cycle, activation, and apoptosis-associated genes. Kienle DL, Korz C, Hosch B, Benner A, Mertens D, Habermann A, Krober A, Jager U, Lichter P, Dohner H, Stilgenbauer S. Department of Internal Medicine III, University of Ulm, Robert-Koch-Strasse 8, 89081 Ulm, Germany. PURPOSE: In patients with chronic lymphocytic leukemia (CLL), the VH mutation status and genomic aberrations (13q-, +12q, 11q-, 17p-) identify distinct prognostic subgroups. The aim was to elucidate biologic mechanisms through which these genetic markers may exert their pathogenic influence. PATIENTS AND METHODS: Twenty-four genes involved in apoptosis, cell cycle, B-cell activation, and B-cell receptor (BCR) signaling were analyzed by real-time quantitative reverse transcription polymerase chain reaction (RQ-PCR) in 82 CLL cases constituting prototypic genetic CLL subgroups as defined by the VH mutation status and the genomic aberrations 13q-, +12, 11q-, and 17p-. RESULTS: The VH mutation subgroups were characterized by a differential expression of the BCR associated genes ZAP70 and PI3K. Among the subgroups defined by genomic aberrations, there was a deregulation of candidate genes from the affected critical genomic regions such as CDK4 (up), ATM (down), and TP53 (down) in the groups +12, 11q-, and 17p-, respectively. Additionally, the genomic subgroups were characterized by a significant deregulation of cell cycle and apoptosis regulators: AKT (up) in 13q, E2F1 (up) in +12, MYC (up) and BCL-2 (down) in 17p-, and CCND3 (down) in 11q- as well as 17p-. The 17p- subgroup showed an additional down-regulation of BCR-associated genes such as SYK and PI3K. CONCLUSION: The characteristic gene expression patterns observed implicate a differential regulation of cell cycle, apoptosis, and BCR signaling in the genetic subgroups illustrating distinct pathomechanisms and are evidence for a gene dosage effect being operative in CLL. These findings link the biologic diversity and clinical heterogeneity of CLL. PMID: 15867199 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 20: Cancer Genet Cytogenet. 2005 May;159(1):74-8. Burkitt-type acute leukemia in a patient with B-prolymphocytic leukemia: evidence for a common origin. Nguyen-Khac F, Davi F, Receveur A, Maloum K, Morel V, Le Garff-Tavernier M, Ong J, Berger R, Leblond V, Merle-Beral H. Service d'Hematologie Biologique, Groupe Hospitalier Pitie-Salpetriere, Paris, France. florence.nguyen@psl.ap-hop-paris.fr Burkitt-type acute leukemia cells were present in the bone marrow of a patient with B-prolymphocytic leukemia diagnosed from peripheral blood cell morphology. Immunophenotype analysis confirmed morphological patterns. Cytogenetic and fluorescence in situ hybridization (FISH) analysis showed an identical t(8;22)(q24;q21) with MYC locus rearrangement in blood and bone marrow cells, with additional chromosome abnormalities in the bone marrow. In addition, the loss of one copy of the TP53 gene and identical IGH DNA clonal rearrangements were shown with FISH and polymerase chain reaction analysis respectively in the two types of leukemic cells. These data indicated the common origin of the two coexisting leukemias and are the first example of such occurrence in a leukemic patient. Publication Types: Case Reports PMID: 15860362 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 21: Cancer Genet Cytogenet. 2005 May;159(1):1-9. A combination of molecular cytogenetic analyses reveals complex genetic alterations in conventional renal cell carcinoma. Strefford JC, Stasevich I, Lane TM, Lu YJ, Oliver T, Young BD. Cancer Research UK Medical Oncology Unit, Queen Mary University of London, Charterhouse Square, London, UK. jcs@soton.ac.uk Here we report the complex pattern of genomic imbalances and rearrangements in a panel of 19 renal cell carcinoma cell lines detected with molecular cytogenetic analysis. Consistent heterogeneity in chromosome number was found, and most cell lines showed a near-triploid chromosome complement. Several cell lines showed deletions of the TP53 (alias p53), CDKN2A (alias p16), and VHL genes. Multiplex fluorescence in situ hybridization (M-FISH) analysis revealed chromosome 3 translocated to several other partners chromosomes, as well as breakage events commonly affecting chromosomes 1, 5, 8, 10, and 17. The most common abnormality detected with comparative genomic hybridization (CGH) was deletions of chromosome 3p, with loss of the RASSF1, FHIT, and p44S10 loci frequently involved. CGH gain of 5q showed overrepresentation of the EGR1 and CSF1R genes. Recurrent alterations to chromosome 7 included rearrangement of 7q11 and gains of the EGFR, TIF1, and RFC2 genes. Several lines exhibited rearrangement of 12q11 approximately q14 and overrepresentation of CDK4 and SAS loci. M-FISH revealed several other recurrent translocations, and CGH findings included loss of 9p, 14q, and 18q and gain of 8q, 12, and 20. Further genomic microarray changes included loss of MTAP, IGH@, HTR1B, and SMAD4 (previously MADH4) and gains of MYC and TOP1. An excellent correlation was observed between the genomic array and FISH data, demonstrating that this technique is effective and accurate. The aberrations detected here may reflect important pathways in renal cancer pathogenesis. PMID: 15860350 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 22: Oncogene. 2005 Jun 30;24(28):4559-71. Inhibitory effect of c-Myc on p53-induced apoptosis in leukemia cells. Microarray analysis reveals defective induction of p53 target genes and upregulation of chaperone genes. Ceballos E, Munoz-Alonso MJ, Berwanger B, Acosta JC, Hernandez R, Krause M, Hartmann O, Eilers M, Leon J. Departamento de Biologia Molecular y Unidad de Biomedicina-CSIC, Grupo de Biologia Molecular del Cancer, Facultad de Medicina, University of Cantabria, Santander 39011, Spain. We have previously demonstrated that c-Myc impairs p53-mediated apoptosis in K562 human leukemia cells, which lack ARF. To investigate the mechanisms by which c-Myc protects from p53-mediated apoptosis, we used K562 cells that conditionally express c-Myc and harbor a temperature-sensitive allele of p53. Gene expression profiles of cells expressing wild-type conformation p53 in the presence of either uninduced or induced c-Myc were analysed by cDNA microarrays. The results show that multiple p53 target genes are downregulated when c-Myc is present, including p21WAF1, MDM2, PERP, NOXA, GADD45, DDB2, PIR121 and p53R2. Also, a number of genes that are upregulated by c-Myc in cells expressing wild-type conformation p53 encode chaperones related to cell death protection as HSP105, HSP90 and HSP27. Both downregulation of p53 target genes and upregulation of chaperones could explain the inhibition of apoptosis observed in K562 cells with ectopic c-Myc. Myc-mediated impairment of p53 transactivation was not restricted to K562 cells, but it was reproduced in a panel of human cancer cell lines derived from different tissues. Our data suggest that elevated levels of Myc counteract p53 activity in human tumor cells that lack ARF. This mechanism could contribute to explain the c-Myc deregulation frequently found in cancer. PMID: 15856024 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 23: Genes Chromosomes Cancer. 2005 Aug;43(4):414-23. Amplification of IGH/MYC fusion in clinically aggressive IGH/BCL2-positive germinal center B-cell lymphomas. Martin-Subero JI, Odero MD, Hernandez R, Cigudosa JC, Agirre X, Saez B, Sanz-Garcia E, Ardanaz MT, Novo FJ, Gascoyne RD, Calasanz MJ, Siebert R. Institute of Human Genetics, University Hospital Schleswig-Holstein Campus Kiel, Germany. Activation of an oncogene via its juxtaposition to the IGH locus by a chromosomal translocation or, less frequently, by genomic amplification is considered a major mechanism of B-cell lymphomagenesis. However, amplification of an IGH/oncogene fusion, coined a complicon, is a rare event in human cancers and has been associated with poor outcome and resistance to treatment. In this article are descriptions of two cases of germinal-center-derived B-cell lymphomas with IGH/BCL2 fusion that additionally displayed amplification of an IGH/MYC fusion. As shown by fluorescence in situ hybridization, the first case contained a IGH/MYC complicon in double minutes, whereas the second case showed a BCL2/IGH/MYC complicon on a der(8)t(8;14)t(14;18). Additional molecular cytogenetic and mutation analyses revealed that the first case also contained a chromosomal translocation affecting the BCL6 oncogene and a biallelic inactivation of TP53. The second case harbored a duplication of REL and acquired a translocation affecting IGL and a biallelic inactivation of TP53 during progression. Complicons affecting Igh/Myc have been reported previously in lymphomas of mouse models simultaneously deficient in Tp53 and in genes of the nonhomologous end-joining DNA repair pathway. To the best of our knowledge, this is the first time that IGH/MYC complicons have been reported in human lymphomas. Our findings imply that the two mechanisms resulting in MYC deregulation, that is, translocation and amplification, can occur simultaneously. Copyright 2005 Wiley-Liss, Inc. Publication Types: Case Reports PMID: 15852472 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 24: Clin Cancer Res. 2005 Apr 1;11(7):2756-67. Myc down-regulation sensitizes melanoma cells to radiotherapy by inhibiting MLH1 and MSH2 mismatch repair proteins. Bucci B, D'Agnano I, Amendola D, Citti A, Raza GH, Miceli R, De Paula U, Marchese R, Albini S, Felsani A, Brunetti E, Vecchione A. Associazione Fatebenefratelli per la Ricerca-Centro Ricerca S. Pietro and Unita di Radioterapia Oncologica S. Pietro, Fatebenefratelli Hospital, Rome, Italy. bucci.barbara@fbfrm.it PURPOSE: Melanoma patients have a very poor prognosis with a response rate of <1% due to advanced diagnosis. This type of tumor is particularly resistant to conventional chemotherapy and radiotherapy, and the surgery remains the principal treatment for patients with localized melanoma. For this reason, there is particular interest in the melanoma biological therapy. EXPERIMENTAL DESIGN: Using two p53 mutant melanoma models stably expressing an inducible c-myc antisense RNA, we have investigated whether Myc protein down-regulation could render melanoma cells more susceptible to radiotherapy, reestablishing apoptotic p53-independent pathway. In addition to address the role of p53 in the activation of apoptosis, we studied the effect of Myc down-regulation on radiotherapy sensitivity also in a p53 wild-type melanoma cell line. RESULTS: Myc down-regulation is able per se to induce apoptosis in a fraction of the cell population (approximately 40% at 72 hours) and in combination with gamma radiation efficiently enhances the death process. In fact, approximately 80% of apoptotic cells are evident in Myc down-regulated cells exposed to gamma radiation for 72 hours compared with approximately 13% observed after only gamma radiation treatment. Consistent with the enhanced apoptosis is the inhibition of the MLH1 and MSH2 mismatch repair proteins, which, preventing the correction of ionizing radiation mismatches occurring during DNA replication, renders the cells more prone to radiation-induced apoptosis. CONCLUSIONS: Data herein reported show that Myc down-regulation lowers the apoptotic threshold in melanoma cells by inhibiting MLH1 and MSH2 proteins, thus increasing cell sensitivity to gamma radiation in a p53-independent fashion. Our results indicate the basis for developing new antitumoral therapeutic strategy, improving the management of melanoma patients. PMID: 15814658 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 25: J Natl Cancer Inst. 2005 Apr 6;97(7):507-17. Erratum in: J Natl Cancer Inst. 2005 May 18;97(10):780. Effects of light and food schedules on liver and tumor molecular clocks in mice. Filipski E, Innominato PF, Wu M, Li XM, Iacobelli S, Xian LJ, Levi F. INSERM E 0354 Chronotherapeutique des cancers, Hopital P. Brousse and Universite Paris XI, 94807 Villejuif Cedex, France. BACKGROUND: Disrupted circadian coordination accelerates malignant growth, but the molecular mechanism is unclear. METHODS: Healthy or Glasgow osteosarcoma-bearing mice (n = 162) were synchronized with light and darkness over 2-3 weeks, submitted to an 8-hour advance onset of light every 2 days (chronic jet lag) to disrupt circadian coordination, or submitted to chronic jet lag and meal timing to prevent molecular clock alteration. The expression of molecular clock genes and of the cell cycle genes c-Myc and p53 in liver and tumor was determined with quantitative reverse transcription-polymerase chain reaction at six circadian times over a 24-hour period of light and darkness and analyzed with analysis of variance and cosinor. Tumor weight was measured daily over the course of the experiment. All statistical tests were two-sided. RESULTS: In synchronized mice, mean mRNA levels of clock genes Rev-erbalpha, Per2, and Bmal1 varied by 206-, four-, and 26-fold, respectively, over the 24 hours in healthy mouse liver; by 36-, 35-, and 32-fold in the livers of tumor-bearing mice; and by 9.4-, 5.5-, and sixfold in tumor tissue (P = .046 to <.001). In mice subjected to chronic jet lag, the periodic changes were dampened and the clock gene rhythms were temporally shifted in liver and ablated in tumor, and tumor growth was accelerated. Meal timing reversed the chronic jet lag-induced alterations in Rev-erbalpha and Per2 expression in liver and of all three clock genes in tumor and slowed tumor growth. Tumor growth differed as a function of light and feeding schedules (P = .04). No obvious rhythm was detected for p53 or c-Myc in liver or tumor tissues of synchronized mice. In healthy mice subjected to chronic jet lag, the mean level of p53 expression was cut in half (P = .002), and a 12-fold circadian variation in c-Myc mRNA level (P = .03) was induced in the liver of healthy mice, whereas complex expression patterns were found in the liver and tumor of tumor-bearing mice. CONCLUSIONS: Altered light-dark or feeding schedules modified the expression of molecular clock genes and genes involved in carcinogenesis and tumor progression. PMID: 15812076 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 26: J Pathol. 2005 May;206(1):111-20. Abnormal expression of period 1 (PER1) in endometrial carcinoma. Yeh KT, Yang MY, Liu TC, Chen JC, Chan WL, Lin SF, Chang JG. Department of Molecular Medicine, China Medical University Hospital, Taichung, Taiwan. The development of endometrial carcinoma (EC) is a multiple-step process, which includes inactivation of tumour suppressor genes, activation of oncogenes, and disturbance of cancer-related genes. Recent studies have shown that the circadian cycle may influence cancer development and prognosis. In this study, the expression of a circadian gene, PER1, was examined in 35 ECs and paired non-tumour tissues by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Expression levels of PER1 were significantly decreased in EC, and mutational analysis of the coding regions, together with methylation analysis of cytosine-phosphate guanosine (CpG) sites in the promoter area, was performed to investigate the possible mechanisms. The analyses detected four single nucleotide polymorphisms in both tumour and non-tumour tissues, which had no relationship with the expression of PER1. In the promoter area of the PER1 gene, the CpG sites were methylated in 31.4% of ECs, but in 11.4% of paired non-tumour tissues (p < 0.05). These results suggest that the down-regulation of PER1 expression in EC was partly due to inactivation of the PER1 gene by DNA methylation of the promoter and partly due to other factors. Analysis of the relationships between the expression of PER1, P53, c-MYC, cyclin A, cyclin B, and cyclin D1 showed no definite relationship. These results suggest that down-regulation of the PER1 gene disrupts the circadian rhythm, which may favour the survival of endometrial cancer cells. 2005 Pathological Society of Great Britain and Ireland PMID: 15809976 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 27: Arq Gastroenterol. 2004 Oct-Dec;41(4):225-8. Epub 2005 Mar 29. [Immunohistochemical detection of p21ras, c-myc and p53 oncoproteins in hepatocellular carcinoma and in non-neoplastic liver tissue] [Article in Portuguese] Pannain VL, Bottino AC, Santos RT, Coelho HS, Ribeiro-Filho J, Alves VA. Departamento de Patologia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro. pannain@hucff.ufrj.br BACKGROUND: Genetic and epigenetic alterations have been described in animal hepatocarcinogenesis models but need to be studied in human being. AIMS: To assess the immunoreactivity of p21ras, c-myc and p53 oncoproteins in hepatocellular carcinoma and non neoplastic tissue. Association of the immunoreactivity of these markers with histological grades and patterns, hepatitis B and C were additionally studied. METHODS: Detection of oncoproteins p21ras, c-myc and p53 was performed immunohistochemically in hepatocellular carcinoma (47 cases) and surrounding non neoplastic liver tissue (40 cases). RESULTS: Oncoproteins p21ras, c-myc and p53 were detected in 44,7%, 53,2% and 36,2% of the hepatocellular carcinoma cases, respectively. The p21ras and c-myc immunoreactivity has shown a significant association. However there was no association of p21ras, c-myc and p53 detection with hepatitis B and C virus infections, histological grades and patterns. The same significant association between p21ras and c-myc was observed in non-neoplastic tissue with cirrhosis when compared with tissue without it. The p53 immunoreactivity was negative in all non-neoplastic liver tissue samples. CONCLUSIONS: The immunoreactivity detection of p21ras, c-myc and p53 corroborates previous evidence of their detection in hepatocellular carcinoma that suggest the participation of these proteins in human hepatocarcinogenesis. The significant association between p21ras and c-myc oncoproteins in hepatocellular carcinoma and in cirrhosis can point to an interaction between them mainly, in hepatocarcinogenesis that occurs through cirrhosis. PMID: 15806265 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 28: Biophys J. 2005 Jun;88(6):4312-8. Epub 2005 Apr 1. Comment in: Biophys J. 2005 Jun;88(6):3741. Nano-sizing of specific gene domains in intact human cell nuclei by spatially modulated illumination light microscopy. Hildenbrand G, Rapp A, Spori U, Wagner C, Cremer C, Hausmann M. Applied Optics and Information Processing, Kirchhoff-Institute of Physics, University of Heidelberg, Germany. Although light microscopy and three-dimensional image analysis have made considerable progress during the last decade, it is still challenging to analyze the genome nano-architecture of specific gene domains in three-dimensional cell nuclei by fluorescence microscopy. Here, we present for the first time chromatin compaction measurements in human lymphocyte cell nuclei for three different, specific gene domains using a novel light microscopic approach called Spatially Modulated Illumination microscopy. Gene domains for p53, p58, and c-myc were labeled by fluorescence in situ hybridization and the sizes of the fluorescence in situ hybridization "spots" were measured. The mean diameters of the gene domains were determined to 103 nm (c-myc), 119 nm (p53), and 123 nm (p58) and did not correlate to the genomic, labeled sequence length. Assuming a spherical domain shape, these values would correspond to volumes of 5.7 x 10(-4) microm(3) (c-myc), 8.9 x 10(-4) microm(3) (p53), and 9.7 x 10(-4) microm(3) (p58). These volumes are approximately 2 orders of magnitude smaller than the diffraction limited illumination or observation volume, respectively, in a confocal laser scanning microscope using a high numerical aperture objective lens. By comparison of the labeled sequence length to the domain size, compaction ratios were estimated to 1:129 (p53), 1:235 (p58), and 1:396 (c-myc). The measurements demonstrate the advantage of the SMI technique for the analysis of gene domain nano-architecture in cell nuclei. The data indicate that chromatin compaction is subjected to a large variability which may be due to different states of genetic activity or reflect the cell cycle state. PMID: 15805170 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 29: In Vivo. 2005 Mar-Apr;19(2):465-70. Oncogene amplification and overexpression of oncoproteins in thyroid papillary cancer. Varkondi E, Gyory F, Nagy A, Kiss I, Ember I, Kozma L. Co-operative Research Centre, Semmelweis University, Budapest, H-1367 Budapest 5. Pf 131; Hungary. varkondi@kkk.sote.hu BACKGROUND: Several oncogene aberrations have been found in papillary thyroid cancer, the incidence of which has increased after the accident in Chernoby. The occurrence and prognostic significance of these aberrations may have importance in therapeutic strategies. MATERIALS AND METHODS: Tumour tissues from 24 patients were investigated by Dot-blot DNA hybridisation for c-myc, Ha-ras amplification and p53 deletion, and by immunohistochemical method for cyclin D1, p53 and p21 overexpression. RESULTS: Overexpression of p53 protein was detected in 66.6%, with p21 expression (25%) without any influence on tumour phenotype. Cyclin D1 overexpression was found in 50% to be associated with p21, in inverse relation to Iymphocytic infiltration. Overexpression of estrogen receptor was shown in 4 cyclin D1-positive samples (17%). CONCLUSION: Our results suggest that cyclin D1 overexpression is associated with poor prognosis. The co-expression of cyclin D1 and p21 causes a CDK-independent, estrogen receptor-mediated effect of the cyclin D1 also described in breast cancer. PMID: 15796211 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 30: Mol Cell. 2005 Mar 18;17(6):793-803. HIF-1alpha induces genetic instability by transcriptionally downregulating MutSalpha expression. Koshiji M, To KK, Hammer S, Kumamoto K, Harris AL, Modrich P, Huang LE. Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. Hypoxia promotes genetic instability by undefined mechanisms. The transcription factor HIF-1alpha is crucial for the cellular response to hypoxia and is frequently overexpressed in human cancers, resulting in the activation of genes essential for cell survival. Here, we demonstrate that HIF-1alpha is responsible for genetic instability at the nucleotide level by inhibiting MSH2 and MSH6, thereby decreasing levels of the MSH2-MSH6 complex, MutSalpha, which recognizes base mismatches. HIF-1alpha displaces the transcriptional activator Myc from Sp1 binding to repress MutSalpha expression in a p53-dependent manner; Sp1 serves as a molecular switch by recruiting HIF-1alpha to the gene promoter under hypoxia. Furthermore, in human sporadic colon cancers, HIF-1alpha overexpression is statistically associated with the loss of MSH2 expression, especially when p53 is immunochemically undetectable. These findings indicate that the regulation of DNA repair is an integral part of the hypoxic response, providing molecular insights into the mechanisms underlying hypoxia-induced genetic instability. PMID: 15780936 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 31: J Biol Chem. 2005 May 20;280(20):19992-9. Epub 2005 Mar 18. JNK1 and JNK2 oppositely regulate p53 in signaling linked to apoptosis triggered by an altered fibronectin matrix: JNK links FAK and p53. Tafolla E, Wang S, Wong B, Leong J, Kapila YL. Department of Stomatology, School of Dentistry, University of California, San Francisco, 94143-0512, USA. The extracellular matrix regulates many cellular processes, including survival, and alterations in the matrix or in matrix survival signals can trigger apoptosis. Previously, we showed that an altered fibronectin matrix triggers apoptosis in primary cells via a novel pathway regulated by transcriptionally mediated decreases in p53 and c-Myc levels. Here we report that this apoptotic mechanism is propagated by decreased phosphorylation of focal adhesion kinase (FAK), which is linked to increased phosphorylation of c-Jun N-terminal kinase (JNK) and to decreased levels of p53. FAK is physically and spatially linked to JNK and p53, which relocalize from the nucleus to the cell membrane to mediate this interaction. Further, p53 participates in a feedback mechanism with JNK to regulate this apoptotic process and is oppositely regulated by JNK1 and JNK2. PMID: 15778501 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 32: Zhonghua Zhong Liu Za Zhi. 2004 Nov;26(11):678-81. [Apoptosis-related gene expression and its clinical significance of human osteosarcoma.] [Article in Chinese] Wu X, Chen ZR, Zhang GJ. Department of Orthopaedics, Zhongshan Hospital, Fudan University, Shanghai 200032, China. wuxinggood@163.com OBJECTIVE: To explore the prognostic markers in osteosarcoma. METHODS: Expressions of p53, c-myc, bcl-2 and apoptosis index (AI) in 28 osteosarcoma specimens were detected by ABC immunohistochemistry and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labelling (TUNEL). The relationship between gene expression and apoptosis, and their correlations with pathologic classification and prognostic factors were analyzed. RESULTS: There was negative correlation between the expressions of p53, c-myc, bcl-2 protein and AI, which was closely related to the long term survival of patients but was not related to pathologic types of the tumor. CONCLUSION: The expressions of p53, c-myc, bcl-2 protein and AI can be used as an index for predicting the progression and prognosis of osteosarcoma. PMID: 15777507 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 33: J Virol. 2005 Apr;79(7):4246-56. Silencing of integrated human papillomavirus type 18 oncogene transcription in cells expressing SerpinB2. Darnell GA, Antalis TM, Rose BR, Suhrbier A. Queensland Institute of Medical Research, University of Queensland, Brisbane, Queensland, Australia. The serine protease inhibitor SerpinB2 (PAI-2), a major product of differentiating squamous epithelial cells, has recently been shown to bind and protect the retinoblastoma protein (Rb) from degradation. In human papillomavirus type 18 (HPV-18)-transformed epithelial cells the expression of the E6 and E7 oncoproteins is controlled by the HPV-18 upstream regulatory region (URR). Here we illustrate that PAI-2 expression in the HPV-18-transformed cervical carcinoma line HeLa resulted in the restoration of Rb expression, which led to the functional silencing of transcription from the HPV-18 URR. This caused loss of E7 protein expression and restoration of multiple E6- and E7-targeted host proteins, including p53, c-Myc, and c-Jun. Rb expression emerged as sufficient for the transcriptional repression of the URR, with repression mediated via the C/EBPbeta-YY1 binding site (URR 7709 to 7719). In contrast to HeLa cells, where the C/EBPbeta-YY1 dimer binds this site, in PAI-2- and/or Rb-expressing cells the site was occupied by the dominant-negative C/EBPbeta isoform liver-enriched transcriptional inhibitory protein (LIP). PAI-2 expression thus has a potent suppressive effect on HPV-18 oncogene transcription mediated by Rb and LIP, a finding with potential implications for prognosis and treatment of HPV-transformed lesions. PMID: 15767426 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 34: Mol Cell Biol. 2005 Mar;25(6):2395-405. The novel ETS factor TEL2 cooperates with Myc in B lymphomagenesis. Cardone M, Kandilci A, Carella C, Nilsson JA, Brennan JA, Sirma S, Ozbek U, Boyd K, Cleveland JL, Grosveld GC. Department of Genetics, St. Jude Children's Research Hospital, 332 North Lauderdale, Memphis, TN 38105, USA. The human ETS family gene TEL2/ETV7 is highly homologous to TEL1/ETV6, a frequent target of chromosome translocations in human leukemia and specific solid tumors. Here we report that TEL2 augments the proliferation and survival of normal mouse B cells and dramatically accelerates lymphoma development in Emu-Myc transgenic mice. Nonetheless, inactivation of the p53 pathway was a hallmark of all TEL2/Emu-Myc lymphomas, indicating that TEL2 expression alone is insufficient to bypass this apoptotic checkpoint. Although TEL2 is infrequently up-regulated in human sporadic Burkitt's lymphoma, analysis of pediatric B-cell acute lymphocytic leukemia (B-ALL) samples showed increased coexpression of TEL2 and MYC and/or MYCN in over one-third of B-ALL patients. Therefore, TEL2 and MYC also appear to cooperate in provoking a cadre of human B-cell malignancies. PMID: 15743832 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 35: Nat Cell Biol. 2005 Mar;7(3):215-7. Comment on: Nat Cell Biol. 2005 Mar;7(3):295-302. Nat Cell Biol. 2005 Mar;7(3):303-10. Nat Cell Biol. 2005 Mar;7(3):311-8. The Myc trilogy: lord of RNA polymerases. Oskarsson T, Trumpp A. Publication Types: Comment News PMID: 15738972 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 36: Anticancer Res. 2004 Nov-Dec;24(6):3997-4001. Early effects of transplatin on oncogene activation in vivo. Nemeth A, Nadasi E, Bero A, Olasz L, Ember A, Kvarda A, Bujdoso L, Arany I, Csejtei A, Faluhelyi Z, Ember I. Department of Public Health, Faculty of Medicine, University of Pecs, Hungary. arpadnemeth@freemail.hu The aim of the study was to investigate the early effect of Transplatin (the stereo-isomer of Cisplatin) on oncogenes in inbred CBA/Ca mice. Cisplatin is commonly used for the treatment of squamous cell carcinomas of the head and neck. Cisplatin has a strong oncogene activation effect compared to the structural analogue Transplatin. Body weight equivalent amounts of a human dose of Transplatin were administered intra-peritoneally to 6- to 8-week-old, inbred, female CBA/Ca mice. Twenty-four, 48 and 72 hours after the treatment, RNA was isolated from the target organs and the expressions of c-myc, Ha-ras and p53 genes were examined. Investigation of early changes showed no significant overexpression compared to Cisplatin, which had a significant effect on oncogene expression in the "short-term" in vivo test system. PMID: 15736445 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 37: Oncogene. 2005 May 5;24(20):3369-76. Accumulation and altered localization of telomere-associated protein TRF2 in immortally transformed and tumor-derived human breast cells. Nijjar T, Bassett E, Garbe J, Takenaka Y, Stampfer MR, Gilley D, Yaswen P. Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. We have used cultured human mammary epithelial cells (HMEC) and breast tumor-derived lines to gain information on defects that occur during breast cancer progression. HMEC immortalized by a variety of agents (the chemical carcinogen benzo(a)pyrene, oncogenes c-myc and ZNF217, and/or dominant negative p53 genetic suppressor element GSE22) displayed marked upregulation (10-15 fold) of the telomere-binding protein, TRF2. Upregulation of TRF2 protein was apparently due to differences in post-transcriptional regulation, as mRNA levels remained comparable in finite lifespan and immortal HMEC. TRF2 protein was not upregulated by the oncogenic agents alone in the absence of immortalization, nor by expression of exogenously introduced hTERT genes. We found TRF2 levels to be at least twofold higher than in control cells in 11/15 breast tumor cell lines, suggesting that elevated TRF2 levels are a frequent occurrence during the transformation of breast tumor cells in vivo. The dispersed distribution of TRF2 throughout the nuclei in some immortalized and tumor-derived cells indicated that not all the TRF2 was associated with telomeres in these cells. The process responsible for accumulation of TRF2 in immortalized HMEC and breast tumor-derived cell lines may promote tumorigenesis by contributing to the cells' ability to maintain an indefinite lifespan. PMID: 15735711 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 38: Oncogene. 2005 May 12;24(21):3385-96. topors, a p53 and topoisomerase I-binding RING finger protein, is a coactivator of p53 in growth suppression induced by DNA damage. Lin L, Ozaki T, Takada Y, Kageyama H, Nakamura Y, Hata A, Zhang JH, Simonds WF, Nakagawara A, Koseki H. Department of Molecular Embryology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. The RING family zinc-finger protein topors (topoisomerase I-binding protein) binds not only topoisomerase I, but also p53 and the AAV-2 Rep78/68 proteins. topors maps to human chromosome 9p21, which contains candidate tumor suppressor genes implicated in small cell lung cancers. In this study, we isolated the murine counterpart of topors and investigated its impact on p53 function. The deduced amino-acid sequence of mouse topors exhibits extensive similarity to human topors. Overexpressed myc-tagged topors associates with and stabilizes p53, and enhances the p53-dependent transcriptional activities of p21(Waf1), MDM2 and Bax promoters and elevates endogenous p21(Waf1) mRNA levels. Overexpression of topors consequently results in the suppression of cell growth by cell cycle arrest and/or by the induction of apoptosis. Taken together, these studies identify topors as a positive regulator of p53. The expression of topors is induced by exposure to the genotoxic reagents cisplatin and camptothecin, a DNA topoisomerase I inhibitor. We therefore postulate that topors mediates p53-dependent cellular responses induced by DNA damage, suggesting its physiological role as a tumor suppressor. PMID: 15735665 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 39: Curr Med Chem Anti-Canc Agents. 2005 Jan;5(1):15-27. Cisplatin resistance and transcription factors. Torigoe T, Izumi H, Ishiguchi H, Yoshida Y, Tanabe M, Yoshida T, Igarashi T, Niina I, Wakasugi T, Imaizumi T, Momii Y, Kuwano M, Kohno K. Department of Molecular Biology, University of Occupational and Environmental Health, School of Medicine, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, Fukuoka 807-8555, Japan. Cisplatin is one of the most potent and widely used anti-cancer agents in the treatment of various solid tumors. However, the development of resistance to cisplatin is a major obstacle in clinical treatment. Several mechanisms are thought to be involved in cisplatin resistance, including decreased intracellular drug accumulation, increased levels of cellular thiols, increased nucleotide excision-repair activity and decreased mismatch-repair activity. In general, the molecules responsible for each mechanism are upregulated in cisplatin-resistant cells; this indicates that the transcription factors activated in response to cisplatin might play crucial roles in drug resistance. It is known that the tumor-suppressor proteins p53 and p73, and the oncoprotein c-Myc, which function as transcription factors, influence cellular sensitivity to cisplatin. So far, we have identified several transcription factors involved in cisplatin resistance, including Y-box binding protein-1 (YB-1), CCAAT-binding transcription factor 2 (CTF2), activating transcription factor 4 (ATF4), zinc-finger factor 143 (ZNF143) and mitochondrial transcription factor A (mtTFA). Two of these-YB-1 and ZNF143-lack the high-mobility group (HMG) domain and can bind preferentially to cisplatin-modified DNA in addition to HMG domain proteins or DNA repair proteins, indicating that these transcription factors may also participate in DNA repair. In this review, we summarize the mechanisms of cisplatin resistance and focus on transcription factors involved in the genomic response to cisplatin. Publication Types: Review PMID: 15720258 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 40: Zhongguo Zhong Yao Za Zhi. 2005 Feb;30(3):207-11. [Alteration of activities of telomerase in tanshinone IIA inducing apoptosis of the leukemia cells] [Article in Chinese] Song Y, Yuan SL, Yang YM, Wang XJ, Huang GQ. West China Hospital, Sichuan University, Chengdu 610041, China. OBJECTIVE: To investigate the effect of tanshinone IIA on HL-60 and K562 cells apoptosis, and to assay the inhibition of the telomerase activities in the leukemia cell apoptosis induced by Tanshinone. METHOD: Using the techniques of cell culture in vitro, flow cytometry and PCR-TRAP observed the telomerase activities and apoptosis of HL-60 and K562 cells which treated by Tan IIA. RESULT: 0.5 microg x mL(-1) Tan IIA could obviously inhibit HL-60 and K562 cell lines growth (P < 0.05), down-regulate c-myc, bcl-2 gene and up-regulate c-fos and p53 gene expression as well as induce leukemia cell apoptosis, the apoptotic rates of HL-60 and K562 cells were 11.8% and 21.8% respectively. The telomerase activities significant decreased, the inhibiting rates in HL60 and K562 cells were 30.8% and 50.8% respectively. CONCLUSION: Tan IIA could significantly inhibit the proliferation and telomerase activities of HL-60 and K562 cells and induce the leukemia cell apoptosis. PMID: 15719642 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 41: Blood. 2005 Jun 1;105(11):4445-54. Epub 2005 Feb 17. Mantle-cell lymphoma genotypes identified with CGH to BAC microarrays define a leukemic subgroup of disease and predict patient outcome. Rubio-Moscardo F, Climent J, Siebert R, Piris MA, Martin-Subero JI, Nielander I, Garcia-Conde J, Dyer MJ, Terol MJ, Pinkel D, Martinez-Climent JA. Department of Hematology and Medical Oncology, Hospital Clinico, University of Valencia, Spain. To identify recurrent genomic changes in mantle cell lymphoma (MCL), we used high-resolution comparative genomic hybridization (CGH) to bacterial artificial chromosome (BAC) microarrays in 68 patients and 9 MCL-derived cell lines. Array CGH defined an MCL genomic signature distinct from other B-cell lymphomas, including deletions of 1p21 and 11q22.3-ATM gene with coincident 10p12-BMI1 gene amplification and 10p14 deletion, along with a previously unidentified loss within 9q21-q22. Specific genomic alterations were associated with different subgroups of disease. Notably, 11 patients with leukemic MCL showed a different genomic profile than nodal cases, including 8p21.3 deletion at tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor gene cluster (55% versus 19%; P = .01) and gain of 8q24.1 at MYC locus (46% versus 14%; P = .015). Additionally, leukemic MCL exhibited frequent IGVH mutation (64% versus 21%; P = .009) with preferential VH4-39 use (36% versus 4%; P = .005) and followed a more indolent clinical course. Blastoid variants, increased number of genomic gains, and deletions of P16/INK4a and TP53 genes correlated with poorer outcomes, while 1p21 loss was associated with prolonged survival (P = .02). In multivariate analysis, deletion of 9q21-q22 was the strongest predictor for inferior survival (hazard ratio [HR], 6; confidence interval [CI], 2.3 to 15.7). Our study highlights the genomic profile as a predictor for clinical outcome and suggests that "genome scanning" of chromosomes 1p21, 9q21-q22, 9p21.3-P16/INK4a, and 17p13.1-TP53 may be clinically useful in MCL. PMID: 15718413 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 42: Eur J Clin Invest. 2005 Feb;35(2):140-7. Molecular events associated with accelerated proliferative response in rat livers when partial hepatectomy is preceded by a sham operation. Laurent S, Starkel P, Leclercq IA, Lambotte L, Maiter D, Horsmans Y. Department of Gastroenterology, Universite Catholique de Louvain, 1200 Brussels, Belgium. BACKGROUND: When a sham operation is performed 6 h before partial hepatectomy (PH), the regenerative response is accelerated suggesting that sham operation itself contributes to cellular events leading to proliferation. MATERIALS AND METHODS: In order to examine the mechanisms implicated in this acceleration, we compared the activation of several factors associated with the progression through the cell cycle at various times after PH and after PH preceded by sham operation (S6 h + PH). The effect of a single sham (S) and two combined sham operations (S6 h + S) was also examined. Nonoperated rats were used as controls (C). RESULTS: The early factors NF-kappaB and Stat3 were activated after S6 h + PH and S6 h + S. C-jun expression was increased 0.5 h and 2 h after PH and 6 h after sham. There was no further increase in S6 h + PH and S6 h + S. In contrast, c-myc expression returned to baseline levels after S6 h and a new increase was observed 2 h after S6 h + PH but not after S6 h + S. P53 mRNA was significantly expressed 6 h after S6 h + PH, but at a level similar than that observed 6 and 12 h after PH alone. An earlier increase in c-Ha-ras mRNA and cyclin E protein was found in S6 h + PH, in comparison with PH alone. CONCLUSIONS: The first divergent response between the two combined models involved c-myc expression. However, major differences related to the accelerated liver regenerative response observed after S6 h + PH were found at late time points associating an earlier expression of c-Ha-ras and nuclear cyclin E. PMID: 15667586 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 43: Ann N Y Acad Sci. 2004 Dec;1028:90-103. Targeted delivery of oncogene-selective antisense oligonucleotides in neuroectodermal tumors: therapeutic implications. Pastorino F, Brignole C, Marimpietri D, Di Paolo D, Zancolli M, Pagnan G, Ponzoni M. Differentiation Therapy Unit, Laboratory of Oncology, G. Gaslini Children's Hospital, Largo G. Gaslini 5, 16148, Genoa, Italy. Neuroectodermal tumors are highly malignant and increasingly common tumors. Because the cure rate of these neoplasias by conventional treatment is very low, new therapeutic approaches are needed. Entrapping high concentrations of cytotoxic drugs and/or oligonucleotides within stabilized liposomal formulations represents an emerging modality of antitumor treatment. Here, we tested the in vitro and in vivo antitumor effects of a novel antisense oligodeoxynucleotide (asODN) liposomal formulation, the coated cationic liposomes (CCL), by targeting the c-myc and the c-myb oncogenes on melanoma and neuroblastoma, respectively, through the use of a monoclonal antibody against the disialoganglioside GD2, selectively expressed by neuroectoderma-derived tumors. Our methods produced GD2-targeted liposomes that stably entrapped 90 percent of added asODNs. These liposomes showed selective binding for GD2-positive tumor cells in vitro. Neuroblastoma cells treated with free myb-as or nontargeted CCL-myb-as showed the same level of c-myb protein expression as control cells. In contrast, c-myb protein expression of cells treated with aGD2-CCL-myb-as was inhibited by approximately 70 percent. Melanoma and neuroblastoma cell proliferation was inhibited to a greater extent by GD2-targeted liposomes containing c-myc or c-myb asODNs than by nontargeted liposomes or free asODNs. Mice bearing established subcutaneous human melanoma xenografts treated with aGD2-CCL-myc-as exhibited significantly reduced tumor growth and increased survival. The mechanism for the antitumor effects appears to be downregulation of the expression of the c-myc protein, induction of p53, and inhibition of Bcl-2 proteins, leading to extensive tumor cell apoptosis. In contrast, the increased life span obtained in a neuroblastoma pseudometastatic mouse model with the liposomal c-myb asODNs seems to be due to a synergistic mechanism: specific targeting to neuroblastoma cancer cells, downmodulation of c-myb protein expression, and stimulation of the innate immune system. These results suggest that inhibition of c-myc or c-myb proto-oncogenes by GD2-targeted antisense therapy could provide an effective approach for the treatment of neuroectodermal tumors in an adjuvant setting. PMID: 15650235 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 44: Int J Cancer. 2005 May 10;114(6):917-25. Novel murine B-cell lymphoma/leukemia model to study BCL2-driven oncogenesis. Meijerink JP, Van Lieshout EM, Beverloo HB, Van Drunen E, Mensink EJ, Macville M, Pieters R. Department of Pediatrics, Division of Oncology/Hematology, Erasmus MC Rotterdam-Sophia Children's Hospital, NL-3015GE Rotterdam, The Netherlands. j.meijerink@erasmusmc.nl The BCL-2 family has been implicated in the pathogenesis of various hematopoietic malignancies, including follicular non-Hodgkin lymphoma and B-cell chronic lymphocytic leukemia. To identify genes that act synergistically in BCL2-enforced leukemogenesis, we developed a murine B-cell lymphoma/leukemia model based on the IL-3-dependent Balb/C pro-B line (FL5.12). FL5.12 cells were stably transfected with antiapoptotic BCL-2 alone or in combination with proapoptotic BAX or nonfunctional mutant BAX, thereby creating various levels of imbalance within the BCL-2 family. Transfectants were intravenously injected into normal Balb/C mice. Whereas FL5.12 cells did not provoke leukemia, mice injected with stable transfectants died of leukemia over time. Disease incidence and latency time depended on the degree of imbalance in the BCL-2 family, supporting a model whereby BCL2 drives tumorigenesis. All mice presented with hepatosplenomegaly and leukemic FL5.12 cells in peripheral blood and bone marrow compartments. Leukemic conversion was accompanied by secondary genetic aberrations leading to clonal IL-3-responsive leukemia. Cellular transformation was independent of alterations in c-Myc or downstream apoptotic pathway. Leukemic clones retained a normal DNA damage response leading to elevated P53 and P21 levels and cell cycle arrest upon irradiation. In conclusion, our mouse model may prove a valuable tool to identify genes that cooperate in BCL2-enforced lymphoma/leukemogenesis. PMID: 15645425 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 45: Proc Natl Acad Sci U S A. 2005 Jan 18;102(3):731-6. Epub 2005 Jan 11. The p53 regulatory gene MDM2 is a direct transcriptional target of MYCN in neuroblastoma. Slack A, Chen Z, Tonelli R, Pule M, Hunt L, Pession A, Shohet JM. Center for Cell and Gene Therapy, Texas Children's Cancer Center, Baylor College of Medicine, 1102 Bates Street, Houston, TX 77030, USA. The MYCN oncogene is the major negative prognostic marker in neuroblastoma with important roles in both the pathogenesis and clinical behavior of this aggressive malignancy. MYC oncogenes activate both proliferative and apoptotic cellular pathways and, accordingly, inhibition of p53-mediated apoptosis is a prerequisite for MYC-driven tumorigenesis. To identify novel transcriptional targets mediating the MYCN-dependent phenotype, we screened a MYCN-amplified neuroblastoma cell line by using chromatin immunoprecipitation (ChIP) cloning. We identified the essential p53 inhibitor and protooncogene MDM2 as a putative target. MDM2 has multiple p53-independent functions modulating cell cycle and transcriptional events. Standard ChIP with MYCN antibodies established the binding of MYCN to a consensus E-box within the human MDM2 promoter. Oligonucleotide pull-down assays further established the capacity of MYCN to bind to this promoter region, confirming the ChIP results. Luciferase reporter assays confirmed the E-box-specific, MYCN-dependent regulation of the MDM2 promoter in MYCN-inducible neuroblastoma cell lines. Real-time quantitative PCR and Western blot analysis demonstrated a rapid increase in endogenous MDM2 mRNA and MDM2 protein upon induction of MYCN. Targeted inhibition of MYCN in a MYCN-amplified neuroblastoma cell line resulted in decreased MDM2 expression levels with concomitant stabilization of p53 and induction of apoptosis. Our finding that MYCN directly modulates baseline MDM2 levels suggests a mechanism contributing to the pathogenesis of neuroblastoma and other MYC-driven malignancies through inhibition of MYC-stimulated apoptosis. PMID: 15644444 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 46: J Pharm Pharmacol. 2005 Jan;57(1):83-92. Microarray analysis of bicalutamide action on telomerase activity, p53 pathway and viability of prostate carcinoma cell lines. Bouchal J, Baumforth KR, Svachova M, Murray PG, von Angerer E, Kolar Z. Laboratory of Molecular Pathology and Institute of Pathology, Palacky University, Hnevotinska 3, 775 15 Olomouc, Czech Republic. bouchal@tunw.upol.cz Bicalutamide is a non-steroidal anti-androgen commonly used in the treatment of prostate carcinoma. We analysed the transcriptional response to bicalutamide treatment with the aim of explaining the inhibition of telomerase in the androgen-sensitive cell line LNCaP and the effects of bicalutamide on the androgen-insensitive cell line DU145. Cells treated with 80 muM bicalutamide in steroid-depleted medium for 1 day were analysed in duplicate by Affymetrix Human Genome Focus Arrays. Response to bicalutamide in LNCaP cells was represented by downregulation of androgen-regulated genes, activation of the p53 pathway and inhibition of telomerase, which was associated with downregulation of v-myc avian myelocytomatosis viral oncogene homologue (MYC) and telomerase reverse transcriptase subunit. In DU145 cells we observed the influence of cell density on bicalutamide effectivity such that highly confluent cells showed lesser sensitivity than low confluent ones. In conclusion, we provide an explanation for telomerase inhibition after androgen receptor blockade in LNCaP cells and we also report activation of the p53 pathway in LNCaP cells and in-vitro sensitivity to bicalutamide of low confluent androgen-insensitive DU145 cells. These findings might have implications for both experimental and clinical research into prostate cancer. In particular, activation of the p53 pathway after treatment with 80 microM bicalutamide could justify usage of bicalutamide dosages higher than 150 mg daily in androgen-sensitive carcinoma therapy. PMID: 15638997 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 47: J Neuropathol Exp Neurol. 2004 Dec;63(12):1211-24. Prognosis-related molecular markers in pediatric central nervous system tumors. Rickert CH. Institute of Neuropathology, Department of Pediatric Hematology and Oncology, Munster University Hospital, Germany. rickchr@uni-muenster.de In the wake of recent progress in understanding the genetic pathways involved in the development of brain tumors, a major goal is to correlate molecular data with clinical outcome, survival, and response to treatment modalities. This is of particular importance among the pediatric population. Reliable prognostic factors could potentially permit a tailoring of therapy in that only patients with the most aggressive tumors would receive the most intense treatments. A survey of publications about prognosis-related molecular features among pediatric brain tumors revealed 74 series, of which 46 presented statistically significant outcome-associated parameters as defined by a p value <0.05. Most investigations revealing significant prognosis-related features were performed on medulloblastomas (34 publications), followed by astrocytic tumors (6 publications) and ependymomas (5 publications). Promising approaches and molecular markers include gene expression profiles, DNA ploidy, loss of heterozygosity and chromosomal aberrations as detected by CGH and FISH (1q, 17p, 17q), as well as oncogenes/ tumor suppressor genes and their proteins (TP53, PTEN, c-erbB2, N-myc, c-myc), growth factor and hormonal receptors (PDGFRA, VEGF, EGFR, HER2, HER4, ErbB-2, hTERT, TrkC), cell cycle genes (p27) and cell adhesion molecules, as well as factors potentially related to therapeutic resistance (multi-drug resistance, DNA topoisomerase IIalpha, metallothionein, P-glycoprotein, tenascin). This review discusses the predictive potential of molecular markers for clinical outcome and their influence on therapeutic decision-making among children with brain tumors. Publication Types: Review Review, Tutorial PMID: 15624758 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 48: J Ethnopharmacol. 2005 Jan 15;96(3):375-83. Epub 2004 Nov 18. Growth arrest and non-apoptotic programmed cell death associated with the up-regulation of c-myc mRNA expression in T-47D breast tumor cells following exposure to Epipremnum pinnatum (L.) Engl. hexane extract. Tan ML, Muhammad TS, Najimudin N, Sulaiman SF. School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia. Epipremnum pinnatum (L.) Engl. hexane extract produced a significant growth inhibition against T-47D breast carcinoma cells and analysis of cell death mechanisms indicated that the extract elicited a non-apoptotic programmed cell death. T-47D cells exposed to the extract at EC(50) concentration (72 h) for 24 h failed to demonstrate typical DNA fragmentation associated with apoptosis, as carried out using a modified TUNEL assay. In addition, acute exposure to the extract produced an insignificant regulation of caspase-3 and p53 mRNA expression but increased in the c-myc mRNA expression. Ultrastructural analysis using transmission electron microscope demonstrated distinct vacuolated cells, which strongly indicated a Type II non-apoptotic cell death although the changes in chromatin were also detected. The presence of non-apoptotic programmed cell death was then reconfirmed with annexin-V and propidium iodide staining. These findings suggested that up-regulation of c-myc mRNA expression may have contributed to the growth arrest and Type II non-apoptotic programmed cell death in the Epipremnum pinnatum (L.) Engl. hexane extract-treated T-47D cells. PMID: 15619555 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 49: Oncogene. 2005 Feb 17;24(8):1461-6. dapk1, encoding an activator of a p19ARF-p53-mediated apoptotic checkpoint, is a transcription target of p53. Martoriati A, Doumont G, Alcalay M, Bellefroid E, Pelicci PG, Marine JC. Laboratory for Molecular Cancer Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Technologiepark, 927, Ghent B-9052, Belgium. The p53 tumour suppressor functions as a transcriptional activator, and several p53-inducible genes that play a critical proapoptotic role have been described. Moreover, p53 regulates the expression of various proteins participating in autoregulatory feedback loops, including proteins that negatively control p53 stability (Mdm2 and Pirh2) or modulate stress-induced phosphorylation of p53 on Ser-46 (p53DINP1 or Wip1), a key event for p53-induced apoptosis. Here, we describe a new systematic analysis of p53 targets using oligonucleotide chips, and report the identification of dapk1 as a novel p53 target. We demonstrate that dapk1 mRNA levels increase in a p53-dependent manner in various cellular settings. Both human and mouse dapk1 genomic loci contain DNA sequences that bind p53 in vitro and in vivo. Since dapk1 encodes a serine/threonine kinase previously shown to suppress oncogene-induced transformation by activating a p19ARF/p53-dependent apoptotic checkpoint, our results suggest that Dapk1 participates in a new positive feedback loop controlling p53 activation and apoptosis. PMID: 15608685 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 50: Cancer Cell. 2004 Dec;6(6):625-30. Oncogenic cooperation between H-Twist and N-Myc overrides failsafe programs in cancer cells. Valsesia-Wittmann S, Magdeleine M, Dupasquier S, Garin E, Jallas AC, Combaret V, Krause A, Leissner P, Puisieux A. INSERM U590, Centre Leon Berard, Universite Claude Bernard Lyon 1, Lyon F-69008 France. N-Myc oncogene amplification is a frequent event in neuroblastoma and is strongly correlated with advanced disease stage and treatment failure. Similarly to c-Myc oncogenic activation, N-Myc deregulation promotes both cell proliferation and p53-dependent apoptosis by sensitizing cells to a variety of insults. Intriguingly, p53 mutations are uncommon in neuroblastomas, strongly suggesting that an alternative cooperating event circumvents this safeguard against oncogene-driven neoplasia. By performing a pangenomic cDNA microarray analysis, we demonstrate that human Twist is constantly overexpressed in N-Myc-amplified neuroblastomas. H-Twist overexpression is responsible for the inhibition of the ARF/p53 pathway involved in the Myc-dependent apoptotic response. This oncogenic cooperation of two key regulators of embryogenesis causes cell transformation and malignant outgrowth. PMID: 15607966 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 51: Am J Physiol Cell Physiol. 2005 May;288(5):C1058-73. Epub 2004 Dec 15. Id2 and p53 participate in apoptosis during unloading-induced muscle atrophy. Siu PM, Alway SE. Division of Exercise Physiology, West Virginia Univ. School of Medicine, Robert C. Byrd Health Science Center, Morgantown, WV 26506-9227, USA. Apoptotic signaling was examined in the patagialis (PAT) muscles of young adult and old quail. One wing was loaded for 14 days to induce hypertrophy and then unloaded for 7 or 14 days to induce muscle atrophy. Although the nuclear Id2 protein content was not different between unloaded and control muscles in either age group, cytoplasmic Id2 protein content of unloaded muscles was higher than that in contralateral control muscles after 7 days of unloading in young quails. Nuclear and cytoplasmic p53 contents and the p53 nuclear index of the unloaded muscles were higher than those in control muscles after 7 days of unloading in young quails, whereas in aged quails, the p53 and Id2 contents and p53 nuclear index of the unloaded muscles were not altered by unloading. Immunofluorescent staining indicated that myonuclei and activated satellite cell nuclei contributed to the increased number of p53-positive nuclei. Conversely, unloading in either young adult or aged PAT muscles did not alter c-Myc protein content. Although Cu-Zn-SOD content was not different in unloaded and control muscles, Mn-SOD content increased in PAT muscles after 7 days of unloading in young quails, suggesting that unloading induced an oxidative disturbance in these muscles. Moderate correlational relationships existed among Id2, p53, c-Myc, SOD, apoptosis-regulatory factors, and TdT-mediated dUTP nick end labeling index. These data indicate that Id2 and p53 are involved in the apoptotic responses during unloading-induced muscle atrophy after hypertrophy in young adult birds. Furthermore, our data suggest that there is an aging-dependent regulation of Id2 and p53 during unloading of previously hypertrophied muscles. PMID: 15601750 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 52: Cancer Chemother Pharmacol. 2005 Mar;55(3):286-94. Epub 2004 Nov 16. DNA damage, c-myc suppression and apoptosis induced by the novel topoisomerase II inhibitor, salvicine, in human breast cancer MCF-7 cells. Lu HR, Meng LH, Huang M, Zhu H, Miao ZH, Ding J. Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 201203, People's Republic of China. Salvicine, a diterpenoid quinone compound, possesses potent in vitro and in vivo antitumor activity. Salvicine is a novel non-intercalative topoisomerase II poison. In this study salvicine induced evident DNA damage, which was further characterized as double-strand breaks mainly in MCF-7 human breast cancer cells. The degree of damage was highly correlated with growth inhibition of MCF-7. Using a PCR-stop assay we demonstrated that this damage was selective. Preferential damage occurred in the p2 promoter region, but not the 3'-end of the protooncogene c-myc. The expression of oncogenes, such as c-myc and c-jun, was additionally investigated. Salvicine induced a dose-dependent decrease in c-myc gene transcription, concomitant with an increase in c-jun expression. Furthermore, reverse-transcription PCR and Western blotting data revealed that salvicine failed to stimulate the mRNA and protein levels of p53 and its downstream targets p21 and bax. The phosphorylation degree of serine 15 of p53, which is thought to be an active form of p53 in response to cellular DNA damage, remained in a steady state. In view of these results, we propose that the downregulation of c-myc resulting from selective damage plays a role in apoptosis signaling. Moreover, salvicine-induced apoptosis in MCF-7 subsequent to DNA damage seems to be mediated through a p53-independent pathway. PMID: 15592835 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 53: Clin Cancer Res. 2004 Nov 15;10(22):7613-20. A clinicobiological model predicting survival in medulloblastoma. Ray A, Ho M, Ma J, Parkes RK, Mainprize TG, Ueda S, McLaughlin J, Bouffet E, Rutka JT, Hawkins CE. Division of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada. PURPOSE: The purpose of this study was to determine the relative contributions of biological and clinical predictors of survival in patients with medulloblastoma (MB). EXPERIMENTAL DESIGN: Clinical presentation and survival information were obtained for 119 patients who had undergone surgery for MB at the Hospital for Sick Children (Toronto, Ontario, Canada) between 1985 and 2001. A tissue microarray was constructed from the tumor samples. The arrays were assayed for immunohistochemical expression of MYC, p53, platelet-derived growth factor receptor-alpha, ErbB2, MIB-1, and TrkC and for apoptosis (terminal deoxynucleotidyl transferase-mediated nick end labeling). Both univariable and multivariable analyses were conducted to characterize the association between survival and both clinical and biological markers. For the strongest predictors of survival, a weighted predictive score was calculated based on their hazard ratios (HRs). The sum of these scores was then used to give an overall prediction of survival using a nomogram. RESULTS: The four strongest predictors of survival in the final multivariable model were the presence of metastatic disease at presentation (HR, 2.02; P=0.01) and p53 (HR, 2.29; P=0.02), TrkC (HR, 0.65; P=0.14), and ErbB2 (HR, 1.51; P=0.21) immunopositivity. A linear prognostic index was derived, with coefficients equal to the logarithm of these HRs. The 5-year survival rate for patients at the 10th, 50th, and 90th percentiles of the score distribution was 80.0%, 71.0%, and 35.7%, respectively, with radiation therapy and 70.5%, 58.5%, and 20.0%, respectively, without radiation therapy. CONCLUSIONS: In this study, we demonstrate an approach to combining both clinical and biological markers to quantify risk in MB patients. This provides further prognostic information than can be obtained when either clinical factors or biological markers are studied separately and establishes a framework for comparing prognostic markers in future clinical studies. PMID: 15569993 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 54: IUBMB Life. 2004 Jul;56(7):409-16. Erratum in: IUBMB Life 2005 Mar;57(3):197. Carmichael, Paul [removed]. Gene expression profiling of p53(+/-) knockout and wild-type mice following diethylstilbestrol administration. Salleh MN, Ismail P, Abdullah AS, Taufiq-Yap YH. Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang Selangor, Malaysia. nazil@medic.upm.edu.my Studies with clastogenic carcinogen diethylstilbestrol (DES) resulted in a broad of spectrum of toxic and carcinogenic effects in humans and rodents, but the cellular and molecular mechanism(s) by which it induces cancer is not clear. To identify putative genetic targets for p53 in vivo, we applied the cDNA macroarray gene expression profiles associated with apoptosis by comparing p53+/- knockout mice and wild-type mice on the kidney and uterus of female mice. p53+/- knockout mice and wild-type mice were treated with DES (500 micromole kg(-1)) or vehicle i.p once daily for 4 days. Total RNAs were obtained from kidney and uterus of both control and DES-treated. The signal intensities of individual gene spots on the membrane were quantified and normalized to the expression level of the GAPDH gene as an internal control. Our results demonstrated that 16 genes; bad, bax, bcl-2, bcl-w, bcl-x, caspase-3, caspase-7, caspase-8, c-myc, E124, GADD45, mdm2, NKkappab1, p53, p21, Rb and trail were up-regulated and six genes; caspase-1, caspase-2, DR5, E2F1, FasL and iNOS did not changed in response to DES treatment in wild-type mice compared to p53+/- knockout mice. Most genes are involved in cell cycle regulation, signal transduction, apoptosis, or transcription. The greatest changes were seen in bad, bcl-x, mdm2, p53 and p21 gene expression in wild-type mice compared to p53+/- knockout mice. In comparing p53 and p21 gene expression in wild-type mice and p53+/- knockout mice, there was an 4.4-fold vs. 1.8-fold; 8-fold vs. 5.2-fold for kidney and 16-fold vs. 5.5-fold; 2.1-fold vs. 8.3-fold for uterus samples increase in induction (respectively). RT-PCR and densitometric analysis was used to confirm the biggest changes of p21, p53 and bax genes. Using this approach, we have identified apoptosis associated genes regulated in response to DES and have revealed putative differences between the isogenic parent strain and p53+/- knockout mice, which will contribute to a better understanding of toxicity/carcinogenicity mechanisms in this model. PMID: 15545218 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 55: Prostate. 2005 May 15;63(3):252-8. Preferential humoral immune response in prostate cancer to cellular proteins p90 and p62 in a panel of tumor-associated antigens. Shi FD, Zhang JY, Liu D, Rearden A, Elliot M, Nachtsheim D, Daniels T, Casiano CA, Heeb MJ, Chan EK, Tan EM. Department of Molecular and Experimental Medicine, W.M. Keck Autoimmune Disease Center, The Scripps Research Institute, La Jolla, California, USA. BACKGROUND: Cytoplasmic p90 autoantigen was recently cloned from a cDNA expression library using serum antibody from a cancer patient. The humoral immune response to p90 in prostate cancer and benign prostatic hyperplasia (BPH) was examined. METHODS: An antigenic fragment of recombinant p90 protein and several other tumor-associated antigens (TAAs) were used in ELISA and Western blotting to detect antibodies in sera from patients with prostate cancer, BPH, and other controls. RESULTS: Autoantibodies to p90 were detected in 30.8% of 133 prostate cancer patients versus 1.5% in 68 BPH patients. When a selected panel of six TAAs including p90 were used for immunoscreening, the cumulative positive reactions in prostate cancer sera reached 92.5%, significantly higher than in BPH and other control sera. Antibodies to p90 showed the highest frequency in prostate cancer (30.8%), followed by antibodies to p62 (22.6%). CONCLUSIONS: A panel of six selected TAAs was shown to have high sensitivity and specificity as immunodiagnostic markers in prostate cancer. (c) 2004 Wiley-Liss, Inc. PMID: 15538718 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 56: Nippon Rinsho. 2004 Oct;62 Suppl 10:489-95. [Recent developments in the molecular genetic understanding of ovarian carcinoma] [Article in Japanese] Shimizu Y. Gynecologic Oncology Center, Sanno Medical Plaza. Publication Types: Review Review, Tutorial PMID: 15535294 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 57: Nippon Rinsho. 2004 Oct;62 Suppl 10:449-53. [Genetic abnormalities in ovarian tumors] [Article in Japanese] Kiguchi K, Okuda Y, Kobayashi Y, Ishizuka B, Ohta T, Fukuda M. Division of Obstetrics and Gynecology, St. Marianna University School of Medicine. Publication Types: Review Review, Tutorial PMID: 15535285 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 58: Nippon Rinsho. 2004 Oct;62 Suppl 10:441-8. [Molecular genetics of ovarian cancer] [Article in Japanese] Yanaihara N, Okamoto A, Takakura S, Yamada K, Ochiai K, Tanaka T. Department of Obstetrics and Gynecology, The Jikei University School of Medicine. Publication Types: Review Review, Tutorial PMID: 15535284 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 59: Anticancer Drugs. 2004 Sep;15(8):779-85. Characterization of molecular events in a series of bladder urothelial carcinoma cell lines with progressive resistance to arsenic trioxide. Hour TC, Huang CY, Lin CC, Chen J, Guan JY, Lee JM, Pu YS. Institute of Biochemistry, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC. Our previous studies have shown that arsenic trioxide (As2O3), a novel anti-cancer agent, may be active against urothelial carcinomas. A series of bladder urothelial carcinoma cells with progressive As2O3 resistance were established and studied to reveal molecular events in relation to the mechanisms of resistance to As2O3. A sensitive parental line (NTUB1) and three As2O3-resistant sublines (NTUB1/As) were used with their IC50s being 0.9, 1.2, 2.5 and 4.9 microM, respectively. Cellular resistance to As2O3 was associated with a lowered proliferation profile (increased p53 and p21Waf1/Cip1 and decreased c-Myc levels) and a greater resistance to apoptosis (elevated Bcl-2 levels). Cells with a stronger resistance had higher expressions of superoxide dismutase (Cu/Zn) and hMSH2 (but not hMLH1). GSH contents were up-regulated in resistant cells in a dose-dependent manner. The DNA-binding activities of NF-kappaB and AP-1 were down-regulated in resistant cells in a dose-dependent manner. Profound molecular alterations occur during the acquisition of secondary As2O3 resistance. Our in vitro cellular model may help to reveal resistance mechanisms to As2O3 in bladder urothelial carcinoma cells. PMID: 15494640 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 60: Br J Haematol. 2004 Nov;127(3):280-4. Multiple myeloma involving central nervous system: high frequency of chromosome 17p13.1 (p53) deletions. Chang H, Sloan S, Li D, Keith Stewart A. Department of Laboratory Hematology, Princess Margaret Hospital, University Health Network, University of Toronto, Toronto, ON, Canada. hong.chang@uhn.on.ca Central nervous system (CNS) involvement is an unusual manifestation in multiple myeloma (MM). The molecular basis of CNS myeloma is poorly understood. MM is characterized by translocations involving the immunoglobulin heavy chain (IgH) locus and frequent 13q deletions. Alterations of p53 or c-myc in MM may represent secondary changes associated with disease progression. We investigated nine patients with CNS MM using interphase fluorescence in situ hybridization (FISH) combined with immunofluorescence detection of the cytoplasmic light chain (cIg-FISH) for the presence of above genomic aberrations. Of nine patients studied, eight cases had hemizygous p53 deletion and 4 had 13q deletions. Of the patients with 13q deletions, two had IgH translocations, one involving 4p16.3 (FGFR3), the other involving 16q23 (c-maf). The high incidence of p53 deletions detected by cIg-FISH in CNS myeloma may be a marker for chromosomal instability, and may be associated with metastatic features of myeloma cells. PMID: 15491286 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 61: Oncogene. 2004 Oct 18;23(48):7957-68. The interplay between Src family kinases and receptor tyrosine kinases. Bromann PA, Korkaya H, Courtneidge SA. Van Andel Research Institute, 333 Bostwick NE, Grand Rapids, MI 49503, USA. Src family tyrosine kinases (SFKs) are involved in a diverse array of physiological processes, as highlighted in this review. An overview of how SFKs interact with, and participate in signaling from, receptor tyrosine kinases (RTKs) is discussed. And also, how SFKs are activated by RTKs, and how SFKs, in turn, can activate RTKs, as well as how SFKs can promote signaling from growth factor receptors in a number of ways including participation in signaling pathways required for DNA synthesis, control of receptor turnover, actin cytoskeleton rearrangements and motility, and survival are discussed. Publication Types: Review Review, Tutorial PMID: 15489913 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 62: Cancer Cell. 2004 Oct;6(4):309-11. Antagonism of Myc functions by Arf. Cleveland JL, Sherr CJ. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. The Arf-Mdm2-p53 tumor suppressor pathway is activated by sustained hyperproliferative signals emanating from oncoproteins such as Myc. A recent study reveals a novel level of feedback control, whereby induced p19(Arf) binds to Myc and blocks cell proliferation by selectively impairing its transactivation functions. PMID: 15488753 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 63: Biochem Biophys Res Commun. 2004 Nov 12;324(2):860-7. Histone deacetylase inhibitor, Trichostatin A, activates p21WAF1/CIP1 expression through downregulation of c-myc and release of the repression of c-myc from the promoter in human cervical cancer cells. Li H, Wu X. Institute of Medical Virology, Wuhan University School of Medicine, Wuhan, Hubei 430071, PR China. huilee6@yahoo.com Histone deacetylase (HDAC) inhibitors have shown promise in clinical cancer therapy and to consistently induce p21WAF1/CIP1 expression in a p53-independent manner and via increased acetylation of the chromatin at the Sp1 sites in the p21WAF1/CIP1 promoter region. However, the exact mechanism by which HDAC inhibitors induce p21WAF1/CIP1 remains unclear. In this study, we observed that Trichostatin A (TSA), a HDAC inhibitor, induced strikingly p21WAF1/CIP1 expression in human cervical cancer (HeLa) cells, and this induction correlated with downregulation of c-myc expression. Coincident with this observation, knock down of c-myc with a c-myc specific small interfering RNA dramatically induced expression of p21WAF1/CIP1 in these cancer cells. These data suggest that c-myc may play a critical role in repression of p21WAF1/CIP1 expression in HeLa cells. More importantly, using chromatin immunoprecipitation assay, we observed for the first time that c-myc bound to the endogenous p21WAF1/CIP1 promoter in untreated HeLa cells, but not in TSA-treated cells. Taken together, TSA induced c-myc downregulation and release from the endogenous p21WAF1/CIP1 promoter contributes, at least partially, to transcriptional activation of the p21WAF1/CIP1 in HeLa cells. PMID: 15474507 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 64: J Biopharm Stat. 2004 Aug;14(3):701-21. Detection of activity centers in cellular pathways using transcript profiling. Pradines J, Rudolph-Owen L, Hunter J, Leroy P, Cary M, Coopersmith R, Dancik V, Eltsefon Y, Farutin V, Leroy C, Rees J, Rose D, Rowley S, Ruttenberg A, Wieghardt P, Sander C, Reich C. Department of Computational Sciences, Millennium Pharmaceuticals, Inc, Cambridge, Massachusetts 021398, USA. joel.pradines@mpi.com We present a new computational method for identifying regulated pathway components in transcript profiling (TP) experiments by evaluating transcriptional activity in the context of known biological pathways. We construct a graph representing thousands of protein functional relationships by integrating knowledge from public databases and review articles. We use the notion of distance in a graph to define pathway neighborhoods. The pathways perturbed in an experiment are then identified as the subgraph induced by the genes, referred to as activity centers, having significant density of transcriptional activity in their functional neighborhoods. We illustrate the predictive power of this approach by performing and analyzing an experiment of TP53 overexpression in NCI-H125 cells. The detected activity centers are in agreement with the known TP53 activation effects and our independent experimental results. We also apply the method to a serum starvation experiment using HEY cells and investigate the predicted activity of the transcription factor MYC. Finally, we discuss interesting properties of the activity center approach and its possible applications beyond the comparison of two experiments. PMID: 15468760 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 65: Oncogene. 2004 Nov 25;23(55):8931-40. Loss of one allele of ARF rescues Mdm2 haploinsufficiency effects on apoptosis and lymphoma development. Eischen CM, Alt JR, Wang P. Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE 68198, USA. ceischen@unmc.edu The tumor suppressor p19ARF inhibits Mdm2, which restricts the activity of p53. Complicated feedback and control mechanisms regulate ARF, Mdm2, and p53 interactions. Here we report that ARF haploinsufficiency completely rescued the p53-dependent effects of Mdm2 haploinsufficiency on B-cell development, survival, and transformation. In contrast to Mdm2+/- B cells, Mdm2+/- B cells deficient in ARF were similar to wild-type B cells in their rates of growth and apoptosis and activation of p53. Consequently, the profoundly reduced numbers of B cells in Mdm2+/-Emu-myc transgenic mice were restored to normal levels in ARF+/-Mdm2+/-Emu-myc transgenics. Additionally, ARF+/-Mdm2+/-Emu-myc transgenics developed lymphomas at rates analogous to those observed for wild-type Emu-myc transgenics, demonstrating that loss of one allele of ARF rescued the protracted lymphoma latency in Mdm2+/-Emu-myc transgenics. Importantly, in ARF+/-Mdm2+/-Emu-myc transgenic lymphomas, p53 was inactivated at the frequency observed in lymphomas of wild-type Emu-myc transgenics. Collectively, these results support a model whereby the stoichiometry of Mdm2 and ARF controls apoptosis and tumor development, which should have significant implications in the treatment of malignancies that have inactivated ARF. PMID: 15467748 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 66: Cancer Biol Ther. 2004 Nov;3(11):1129-34; discussion 1135-6. Epub 2004 Nov 9. Ribozyme targeting HPV16 E6E7 transcripts in cervical cancer cells suppresses cell growth and sensitizes cells to chemotherapy and radiotherapy. Zheng Y, Zhang J, Rao Z. Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA. yazheng@niaid.nih.gov Human Papillomavirus (HPV) is related to more than 90% of cervical cancer. The virus is shown to be essential for the induction and maintenance of the malignant phenotype in cervical cancer. In this report, we designed a hammerhead ribozyme Rz170 to specifically target the HPV16 E6E7 transcripts, and our results demonstrated that Rz170 can cleave HPV16 E6E7 transcripts effectively and with high specificity. When transfected into a HPV16 positive cervical cancer cell, CaSKi, the ribozyme reduced the expression of HPV16 E6 and E7 mRNA, and inhibited cell growth both in vitro and in vivo. The percentage of apoptosis cells was also increased. We found that Rz170 reduced the expression of the viral E6 and E7 proteins, and cellular c-myc, bcl-2 proteins, but increased the expression of p53 and Rb proteins. It is likely that the ribozyme inhibited cervical cancer cell growth by reducing the expression of the HPV16 E6 and E7gene, which may alter the expression of p53, Rb, c-myc and bcl-2, and led to apoptosis in cancer cells. We also found that CaSKi cells transfected with Rz170 showed increased sensitivity to cisplatin and radiation. Our study demonstrated the potential of Rz170 for treating cervical cancer, and the possibility of using a combined therapeutic strategy involving ribozyme, chemotherapy or radiotherapy. PMID: 15467442 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 67: Nat Rev Mol Cell Biol. 2004 Oct;5(10):805-15. Connecting proliferation and apoptosis in development and disease. Hipfner DR, Cohen SM. European Molecular Biology Laboratory, Meyerhofstrasse 1, 169117, Heidelberg, Germany. hipfner@embl.de Cells grow and divide rapidly during embryonic and postnatal development. Net tissue growth reflects the balance between the addition of new cells and the elimination of existing cells by programmed cell death. Cells compete for growth and survival factors to ensure an appropriate balance between the addition and elimination of cells. Elaborate mechanisms ensure that cells do not evade these constraints, and thereby prevent uncontrolled proliferation. Publication Types: Review Review, Tutorial PMID: 15459661 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 68: Int J Cancer. 2004 Nov 10;112(3):536-40. Transgenic overexpression of a dominant negative mutant of FADD that, although counterselected during tumor progression, cooperates in L-myc-induced tumorigenesis. Hueber AO, Bosser S, Zornig M. Institute of Signaling, Developmental Biology and Cancer Research, Centre National de la Recherche Scientifique Unite mixte de Recherche 6543 Centre A. Lacassagne, Nice, France. Activation of the so-called death receptors, e.g., CD95/Fas/Apo-1, is a potent stimulus to trigger apoptosis. Overexpression of the C-terminal FADD deletion mutant FADD-DN blocks death receptor-induced apoptosis, but despite this antiapoptotic activity, lck FADD-DN transgenic mice do not develop lymphomas. To analyze whether functional inactivation of FADD cooperates with Myc overexpression in tumorigenesis, lck FADD-DN transgenic mice were crossed with Emicro L-myc transoncogenic animals. While no tumors were detected in single transgenic FADD-DN or L-myc mice within 15 months, 5 of 17 (29%) FADD-DN/L-myc double transgenic animals developed lymphomas with an average latency period of 47 weeks. Protein analysis of FADD-DN/L-myc tumors showed, however, undetectable levels of FADD-DN protein. FADD-DN protein expression was again lost in 16 of 17 FADD-DN/p53 k.o. T-cell lymphomas, though no significant acceleration of tumorigenesis in P53-deficient lck FADD-DN mice compared to p53 k.o. animals was observed. These data suggest a strong counterselection against the FADD-DN protein during tumor progression, which could be explained by the cell cycle inhibitory activity of FADD-DN. Such counterselection would have to be compensated for by other antiapoptotic mutations, and indeed, strong upregulation of the antiapoptotic Bcl-2 family member Bcl-xL was found in one of the tumors. This in vivo mouse model demonstrates that an antiapoptotic protein involved in the onset of tumorigenesis is selected against and consequently lost during tumor progression because of its additional antiproliferative activity. PMID: 15382083 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 69: J Biol Chem. 2004 Nov 19;279(47):48930-40. Epub 2004 Sep 17. NDRG1 is necessary for p53-dependent apoptosis. Stein S, Thomas EK, Herzog B, Westfall MD, Rocheleau JV, Jackson RS 2nd, Wang M, Liang P. Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA. S.Stein@med.uni-frankfurt.de Although a number of target genes for the tumor suppressor p53 have been described, the mechanism of p53-dependent apoptosis is incompletely understood. Thus, it is essential to identify and characterize additional target genes that could mediate apoptosis. In the study reported here, we isolated a p53-regulated gene named NDRG1 (N-Myc down-regulated gene 1). Its expression is induced by DNA damage in a p53-dependent fashion. The promoter region of the NDRG1 gene contains a p53 binding site that confers p53-dependent transcriptional activation via a heterologous reporter. RNA interference and inducible gene expression approaches suggest that NDRG1 is necessary but not sufficient for p53-mediated caspase activation and apoptosis. This report further supports the notion that p53 controls a network of genes that are required for its apoptotic function. PMID: 15377670 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 70: Methods Mol Med. 2005;106:135-91. Radionuclide-peptide nucleic acid in diagnosis and treatment of pancreatic cancer. Wickstrom E, Tian X, Amirkhanov NV, Chakrabarti A, Aruva MR, Rao PS, Qin W, Zhu W, Sauter ER, Thakur ML. Department of Biochemistry, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA. Publication Types: Review PMID: 15375316 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 71: Genes Dev. 2004 Sep 15;18(18):2269-82. Identification of a novel telomerase repressor that interacts with the human papillomavirus type-16 E6/E6-AP complex. Gewin L, Myers H, Kiyono T, Galloway DA. Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA. The critical immortalizing activity of the human papillomavirus (HPV) type-16 E6 oncoprotein is to induce expression of hTERT, the catalytic and rate-limiting subunit of telomerase. Additionally, E6 binds to a cellular protein called E6-associated protein (E6-AP) to form an E3 ubiquitin ligase that targets p53 for proteasome-dependent degradation. Although telomerase induction and p53 degradation are separable and distinct functions of E6, binding of E6 to E6-AP strongly correlated with the induction of hTERT. Here, we demonstrate using shRNAs to reduce E6-AP expression that E6-AP is required for E6-mediated telomerase induction. A yeast two-hybrid screen to find new targets of the E6/E6-AP E3 ubiquitin ligase complex identified NFX1. Two isoforms of NFX1 were found: NFX1-123, which coactivated with c-Myc at the hTERT promoter, and NFX1-91, which repressed the hTERT promoter. NFX1-91 was highly ubiquitinated and destabilized in epithelial cells expressing E6. Furthermore, knockdown of NFX1-91 by shRNA resulted in derepression of the endogenous hTERT promoter and elevated levels of telomerase activity. We propose that the induction of telomerase by the HPV-16 E6/E6-AP complex involves targeting of NFX1-91, a newly identified repressor of telomerase, for ubiquitination and degradation. PMID: 15371341 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 72: Int Rev Cytol. 2004;238:183-226. Functions of myc:max in the control of cell proliferation and tumorigenesis. Hurlin PJ, Dezfouli S. Portland Shriners Hospitals for Children and Department of Cell and Developmental Biology Oregon Health Sciences University, Portland, Oregon 97201, USA. Deregulation and elevated expression of members of the Myc family of bHLHZip transcription factors are observed in a high percentage of tumors. This close association with human cancers has led to a tremendous effort to define their biological and biochemical activities. Although Myc family proteins have the capacity to elicit a wide range of cell behaviors, their principal function appears to be to drive cells into the cell cycle and to keep them there. However, forced expression of Myc profoundly sensitizes normal cells to apoptosis. Therefore, tumor formation caused by deregulated Myc expression requires cooperating events that disrupt pathways that mediate apoptosis. Myc-dependent tumor formation may also be impeded by a set of related bHLHZip proteins with the demonstrated potential to act as Myc antagonists in cell culture experiments. In this review, we examine the complex activities of Myc family proteins and how their actions might be regulated in the context of a network of bHLHZip proteins. Publication Types: Review Review, Tutorial PMID: 15364199 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 73: Cancer Lett. 2004 Oct 28;214(2):133-47. Genetic progression of metastatic melanoma. Rodolfo M, Daniotti M, Vallacchi V. Unit of Melanoma Genetics, Istituto Nazionale per lo Studio e la Cura dei Tumori, via G. Venezian 1, 20133 Milan, Italy. monica.rodolfo@istitutotumori.mi.it Melanoma progression is well defined in its clinical, histopathological and biological aspects, but the molecular mechanism involved and the genetic markers associated to metastatic dissemination are only beginning to be defined. The recent development of high-throughput technologies aimed at global molecular profiling of cancer is switching on the spotlight at previously unknown candidate genes involved in melanoma, such as WNT5A and BRAF. In fact, several tumor suppressors and oncogenes have been shown to be involved in melanoma pathogenesis, including CDKN2A, PTEN, TP53, RAS and MYC, though they have not been related to melanoma subtypes or validated as prognostic markers. Here, we have reviewed the published data relative to the major genes involved in melanoma pathogenesis, which may represent important markers for the identification of genetic profiles of melanoma subtypes. Publication Types: Review Review, Tutorial PMID: 15363539 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 74: Nature. 2004 Oct 7;431(7009):712-7. Epub 2004 Sep 8. p19ARF directly and differentially controls the functions of c-Myc independently of p53. Qi Y, Gregory MA, Li Z, Brousal JP, West K, Hann SR. Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2175, USA. Increased expression of the oncogenic transcription factor c-Myc causes unregulated cell cycle progression. c-Myc can also cause apoptosis, but it is not known whether the activation and/or repression of c-Myc target genes mediates these diverse functions of c-Myc. Because unchecked cell cycle progression leads to hyperproliferation and tumorigenesis, it is essential for tumour suppressors, such as p53 and p19ARF (ARF), to curb cell cycle progression in response to increased c-Myc (refs 2, 3). Increased c-Myc has previously been shown to induce ARF expression, which leads to cell cycle arrest or apoptosis through the activation of p53 (ref. 4). Here we show that ARF can inhibit c-Myc by a unique and direct mechanism that is independent of p53. When c-Myc increases, ARF binds with c-Myc and dramatically blocks c-Myc's ability to activate transcription and induce hyperproliferation and transformation. In contrast, c-Myc's ability to repress transcription is unaffected by ARF and c-Myc-mediated apoptosis is enhanced. These differential effects of ARF on c-Myc function suggest that separate molecular mechanisms mediate c-Myc-induced hyperproliferation and apoptosis. This direct feedback mechanism represents a p53-independent checkpoint to prevent c-Myc-mediated tumorigenesis. PMID: 15361884 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 75: Appl Immunohistochem Mol Morphol. 2004 Jun;12(2):97-104. Immunophenotypic and genotypic characterization of progression in follicular lymphomas. Natkunam Y, Soslow R, Matolcsy A, Dolezal M, Bhargava V, Knowles DM, Warnke R. Department of Pathology, Stanford University Medical Center, Stanford, California 94305, USA. yaso@stanford.edu Progression of follicular lymphomas (FLs) is often accompanied by a spectrum of histologic changes and an aggressive clinical course. Although molecular alterations have been implicated in this event, the underlying factors are largely unknown. We studied the expression of selected tumor suppressor genes (P53 and retinoblastoma [RB]), oncogenes (MYC and BCL2), and a transferrin-receptor related protein (Trump) in sequential biopsies in 16 patients. Eleven patients progressed from grade I or II FL to aggressive B-cell lymphomas with diffuse morphology, whereas 5 patients presented with diffuse aggressive lymphomas and recurred with indolent lymphomas. Immunoreactivity for P53 correlated with higher histologic grade in lymphomas progressing from indolent to aggressive; however, only 1 patient who presented with aggressive lymphoma demonstrated a P53 gene mutation. Neither P53 immunoreactivity nor genotypic alterations correlated with presentation with an aggressive histology and relapse with FL. Growth fraction, as assessed by Ki-67 staining, and Trump expression correlated with histologic grade. Immunoreactivity for RB, BCL2, and MYC was seldom associated with progression. Eight of 9 cases tested exhibited identical immunoglobulin heavy and light chain rearrangements or identical BCL2 gene rearrangements in the sequential lymphomas. We conclude that P53 and Trump protein expression and proliferation activity correlate with histologic grade, but not with recurrence or progression of FL. Our results further indicate that progression of FL to diffuse aggressive lymphomas and presentation of an aggressive B-cell lymphoma followed by FL are clonally related. PMID: 15354733 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 76: Maturitas. 2004 Sep 24;49(1):34-43. Oncogenic pathways in hereditary and sporadic breast cancer. Kenemans P, Verstraeten RA, Verheijen RH. Department of Obstetrics and Gynaecology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands. Kenemans@vumc.nl Cancer is a genetic disease. Breast cancer tumorigenesis can be described as a multi-step process in which each step is thought to correlate with one or more distinct mutations in major regulatory genes. The question addressed is how far a multi-step progression model for sporadic breast cancer would differ from that for hereditary breast cancer. Hereditary breast cancer is characterized by an inherited susceptibility to breast cancer on basis of an identified germline mutation in one allele of a high penetrance susceptibility gene (such as BRCA1, BRCA2, CHEK 2, TP53 or PTEN). Inactivation of the second allele of these tumour suppressor genes would be an early event in this oncogenic pathway (Knudson's "two-hit" model). Sporadic breast cancers result from a serial stepwise accumulation of acquired and uncorrected mutations in somatic genes, without any germline mutation playing a role. Mutational activation of oncogenes, often coupled with non-mutational inactivation of tumour suppressor genes, is probably an early event in sporadic tumours, followed by more, independent mutations in at least four or five other genes, the chronological order of which is likely less important. Oncogenes that have been reported to play an early role in sporadic breast cancer are MYC, CCND1 (Cyclin D1) and ERBB2 (HER2/neu). In sporadic breast cancer, mutational inactivation of BRCA1/2 is rare, as inactivation requires both gene copies to be mutated or totally deleted. However, non-mutational functional suppression could result from various mechanisms, such as hypermethylation of the BRCA1 promoter or binding of BRCA2 by EMSY. In sporadic breast tumorigenesis, at least three different pathway-specific mechanisms of tumour progression are recognizable, with breast carcinogenesis being different in ductal versus lobular carcinoma, and in well differentiated versus poorly differentiated ductal cancers. Thus, different breast cancer pathways emerge early in the process of carcinogenesis, ultimately leading to clinically different tumour types. As mutations acquired early during tumorigenesis will be present in all later stages, large-scale gene expression profiling using DNA microarray analysis techniques can help to classify breast cancers into clinically relevant subtypes. Publication Types: Review Review, Tutorial PMID: 15351094 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 77: Hum Gene Ther. 2004 Aug;15(8):813-9. Adenovirus vector-mediated doxycycline-inducible RNA interference. Hosono T, Mizuguchi H, Katayama K, Xu ZL, Sakurai F, Ishii-Watabe A, Kawabata K, Yamaguchi T, Nakagawa S, Mayumi T, Hayakawa T. Division of Cellular and Gene Therapy Products, National Institute of Health Sciences, Tokyo 158-8501, Japan. RNA interference (RNAi) is a powerful tool for the knockdown of gene expression. Here, we report on the development of an adenovirus (Ad) vector-mediated doxycycline (Dox)-inducible small interfering RNA (siRNA) expression system. We used this siRNA system to control the expression of p53 and c-Myc in human cancer cells. Coinfection of Ad vectors containing the siRNA expression system under the control of the Dox-inducible H1 promoter and Ad vectors expressing a tetracycline repressor inhibited the expression levels of p53 and c-Myc in a dose-dependent manner with both Dox and viral dose. Regulated silencing of p53 and c-Myc expression was obtained. Because an Ad vector-mediated inducible RNAi system can efficiently transduce a variety of cell types in vitro and in vivo, and the degree of loss of gene expression can be modulated according to the dose of Dox, this expression system should be a useful tool for both basic research on the analysis of gene function and therapeutic applications of RNAi. Copryright Mary Ann Liebert, Inc. PMID: 15319038 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 78: J Cell Sci. 2004 Aug 1;117(Pt 17):3855-65. Epub 2004 Jul 20. pRb, Myc and p53 are critically involved in SV40 large T antigen repression of PDGF beta-receptor transcription. Uramoto H, Hackzell A, Wetterskog D, Ballagi A, Izumi H, Funa K. Department of Cell Biology, Institute of Anatomy and Cell Biology, Goteborg University, Box 420, SE-405 30 Gothenburg, Sweden. The expression of the PDGF beta-receptor is tightly regulated during a normal cell cycle. c-Myc and p73alpha repress transcription of the receptor through interaction with NF-Y. In ST15A cells which stably express the temperature-sensitive SV40 large T antigen (LT) the receptor expression and ligand binding decreased under the permissive condition. Transient expression of the LT, but not small t, decreased the endogenous receptor expression at mRNA and protein levels in NIH3T3 cells but not in the myc-null HO15.19 cells. The wild-type LT, but not the various pRb or p53 binding defective LT mutants, represses the PDGF beta-receptor promoter activity. Moreover, the inability of the LT-mediated repression in the myc-null cells, the Rb-null 3T3 cells, and the Saos-2 cells lacking pRb and p53, indicates that Myc, pRb and p53 are all necessary elements. PDGF beta-receptor promoter-luciferase assays revealed that the CCAAT motif is important for the repression. Furthermore, p53 was found to increase the promoter activity mainly via the upstream Sp1 binding sites together with the CCAAT motif in the NIH 3T3 cells. This was confirmed by Schneider's Drosophila line (SL2) cells deficient in both endogenous NF-Y and Sp1. Chromatin immunoprecipitation using ST15A cells revealed that both LT and p53 bound the PDGF beta-receptor promoter and the binding of p53 diminished when LT was expressed in the permissive condition. However, LT binds the promoter in the absence of pRb and p53 in Saos-2 cells stably expressing LT. These results suggest that LT binds the promoter and interferes with NF-Y and Sp1 to repress it in the presence of Myc, pRb and p53. PMID: 15265983 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 79: Gynecol Oncol. 2004 Jul;94(1):40-7. The role of HPV oncoproteins and cellular factors in maintenance of hTERT expression in cervical carcinoma cells. Jeong Seo E, Jung Kim H, Jae Lee C, Tae Kang H, Seong Hwang E. Department of Life Science, University of Seoul, Dongdaemungu, Jeonnongdong 90, Seoul 130-743, South Korea. OBJECTIVE: E6 and E7 oncoproteins of high risk type HPV modulate activities of host components in cell cycle regulation. Many of these factors are also involved in the regulation of telomerase activity or the expression of hTERT, the catalytic subunit. Transcription of E6 and E7 is inhibited by the papillomavirus E2 protein, and ectopic expression of E2 in HeLa cells has been shown to cause activation of the p53-growth inhibitory pathway and downregulation of the hTERT gene. In this study, using E2 transduction in HeLa cells, the relative importance of host and viral factors in the maintenance of hTERT and telomerase activity in cervical carcinoma cells was investigated. METHODS: Depletion of E6/E7 proteins, concomitant upregulation of p53, p21WAF1, and hypophosphorylated Rb, and downregulation of E2F1, c-Myc, and hTERT were achieved in HeLa cells through SV40-mediated E2 transduction. And, through gene transduction, E6 and E7 proteins were separately re-expressed in HeLa cells that were devoid of these proteins. As well, E2F1, c-Myc, and p53 were ectopically expressed in HeLa cells to ascertain their effect on the level of hTERT expression through RT-PCR, Western blotting, and TRAP assays. RESULTS: Continued expression of E2F1 and c-Myc could not prevent hTERT downregulation caused by E2 transduction, but re-expression of either E6 or E7 individually reactivated hTERT expression. Finally, p53 overexpression caused repression of the hTERT gene in the presence of E6 and E7. CONCLUSION: HPV E6 plays an important role in the induction and maintenance of high levels of hTERT in cervical carcinoma cells through direct stimulation of hTERT promoter and prevention of the inhibitory effects of p53. E7, but not E2F1, may contribute to high telomerase activity in cancer cells. PMID: 15262117 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 80: Oncogene. 2004 Sep 23;23(44):7355-65. ATM activity contributes to the tumor-suppressing functions of p14ARF. Li Y, Wu D, Chen B, Ingram A, He L, Liu L, Zhu D, Kapoor A, Tang D. Division of Nephrology, Department of Medicine, McMaster University, Hamilton, ON, Canada. P14/p19ARF (ARF) plays a major role in the activation of p53 by oncogenic signals. The biochemical basis of this has not been fully elucidated. We report here that forced expression of p14ARF enhances phosphorylation of p53 serine 15 (p53S15) in NIH3T3, IMR90 and MCF7 cells. Ectopic expression of the oncogenes c-myc, E2F1 and E1A, all of which activate p53 at least partially via ARF, lead to p53S15 phosphorylation in IMR90 cells. In addition, ectopic expression of p53 also results in p53S15 phosphorylation, suggesting that this is a common event in the ARF-p53 tumor suppression system. Furthermore, p53-, p14ARF-, c-myc- and E2F1-, but not E1A-, induced p53S15 phosphorylation was substantially reduced in AT fibroblasts (GM05823). Downregulation of ATM in MCF7 cells using RNA interference (RNAi) technology significantly attenuated p14ARF- and p53-induced phosphorylation of p53S15. Ectopically expressed ARF in NIH3T3 cells induced ATM nuclear foci and activated ATM kinase. Functionally, ectopic expression of p14ARF and c-myc inhibited the proliferation of IMR90 but not ATM null GM05823 cells, and p14ARF-induced inhibition of MCF7 cell proliferation was significantly attenuated by downregulation of ATM by RNAi. Taken together, these data show a functional role for ATM in ARF-mediated tumor suppression. PMID: 15258567 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 81: Blood. 2004 Nov 1;104(9):2967-75. Epub 2004 Jul 13. Iron chelators with high antiproliferative activity up-regulate the expression of a growth inhibitory and metastasis suppressor gene: a link between iron metabolism and proliferation. Le NT, Richardson DR. Children's Cancer Institute Australia for Medical Research, The Iron Metabolism and Chelation Program, PO Box 81, High St, Randwick, Sydney, New South Wales, 2031 Australia. Iron (Fe) is critical for proliferation, but its precise role in cell cycle progression remains unclear. In this study, we examined the mechanisms involved by assessing the effects of Fe chelators on the expression of molecules that play key roles in this process. In initial studies, gene arrays were used to assess gene expression after incubating cells with 2 Fe chelators, namely, desferrioxamine (DFO) and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), or the DNA-damaging agent, actinomycin D. From the genes assessed, only the N-myc downstream-regulated gene 1 (Ndrg1) was specifically up-regulated by Fe chelation. Although the function of Ndrg1 is unclear, previous studies showed it markedly slows tumor growth and acts as a potent metastasis suppressor. Incubation of cells with chelators markedly increased Ndrg1 mRNA and protein expression, but this was not found with their Fe complexes or when the Fe-binding site had been inactivated. Increased Ndrg1 expression following Fe chelation was related to the permeability and antiproliferative activity of chelators and could be reversed by Fe repletion. Moreover, Ndrg1 up-regulation after chelation occurred at the transcriptional level and was mediated by hypoxia inducible factor-1alpha (HIF-1alpha)-dependent and -independent mechanisms. Our investigation suggests Ndrg1 is a novel link between Fe metabolism and the control of proliferation. PMID: 15251988 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 82: Mol Cancer. 2004 Jul 8;3:18. PTTG/securin activates expression of p53 and modulates its function. Hamid T, Kakar SS. Department of Medicine, University of Louisville, Louisville, KY 40202, USA. t0hami01@louisville.edu BACKGROUND: Pituitary tumor transforming gene (PTTG) is a novel oncogene that is expressed abundantly in most tumors. Overexpression of PTTG induces cellular transformation and promotes tumor formation in nude mice. PTTG has been implicated in various cellular processes including sister chromatid separation during cell division as well as induction of apoptosis through p53-dependent and p53-independent mechanisms. The relationship between PTTG and p53 remains unclear, however. RESULTS: Here we report the effects of overexpression of PTTG on the expression and function of p53. Our results indicate that overexpression of PTTG regulates the expression of the p53 gene at both the transcriptional and translational levels and that this ability of PTTG to activate the expression of p53 gene is dependent upon the p53 status of the cell. Deletion analysis of the p53 gene promoter revealed that only a small region of the p53 gene promoter is required for its activation by PTTG and further indicated that the activation of p53 gene by PTTG is an indirect effect that is mediated through the regulation of the expression of c-myc, which then interacts with the p53 gene promoter. Our results also indicate that overexpression of PTTG stimulates expression of the Bax gene, one of the known downstream targets of p53, and induces apoptosis in a human embryonic kidney cell line (HEK293). This stimulation of bax expression by PTTG is indirect and is mediated through modulation of p53 gene expression. CONCLUSIONS: Overexpression of PTTG activates the expression of p53 and modulates its function, with this action of PTTG being mediated through the regulation of c-myc expression. PTTG also up-regulates the activity of the bax promoter and increases the expression of bax through modulation of p53 expression. PMID: 15242522 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 83: Cancer Detect Prev. 2004;28(3):178-86. Clinical significance of c-myc and p53 expression in head and neck squamous cell carcinomas. Waitzberg AF, Nonogaki S, Nishimoto IN, Kowalski LP, Miguel RE, Brentani RR, Brentani MM. Universidade Federal de Sao Paulo, Sao Paulo, Brazil. c-myc and p53 genes were frequently deregulated in head and neck squamous cell carcinoma (HNSCC). To determine if the concomitant expression of the two oncogenes might have prognostic value, the survival and free disease time of 140 consecutive HNSCC patients followed up for a median time of 29.9 months was analyzed in the light of p53 and c-myc expression assessed by immunohistochemistry. Positive c-myc and p53 staining was detected respectively in 35.7 and 50.7% of the tumors. Double positivity emerged in 16.4% of the cases. Overall-survival of patients was not associated with the immunoreactivity of p53 or c-myc considered separately or grouped in subsets. Considering only the advanced stages, the concomitant expression of both oncogenes in tumors was associated with worse disease-free survival (P = 0.004) suggesting a role for p53 and c-myc genes in progression of this HNSCC subset. Clinical parameters (presence of lymph nodes, histologic grade and tumor width) remained important indicators of overall survival (OS). PMID: 15225897 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 84: Br J Dermatol. 2004 Jun;150(6):1070-80. Pemphigus serum and captopril induce heat shock protein 70 and inducible nitric oxide synthase overexpression, triggering apoptosis in human keratinocytes. Baroni A, Buommino E, Paoletti I, Orlando M, Ruocco E, Ruocco V. Clinica Dermatologica, Facolta di Medicina e Chirurgia II, Universita degli Studi di Napoli, 80131 Naples, Italy. BACKGROUND: Captopril is an angiotensin-converting enzyme inhibitor with sulphydryl groups in its chemical structure. It is commonly used as an antihypertensive drug. The occurrence of pemphigus vulgaris has repeatedly been reported in patients receiving captopril. The capacity of captopril and pemphigus serum to induce acantholysis, in vivo or in vitro, has been demonstrated experimentally. OBJECTIVES: To show that captopril and pemphigus serum, acting by a biochemical and immunological mechanism, respectively, trigger apoptosis. METHODS: Human keratinocyte cells were treated with 15 mmol L-1 captopril or with pemphigus serum. DNA was extracted and the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling method was used to detect apoptosis. RESULTS: DNA fragmentation occurred after 72 h of treatment. Increased expression of p53, c-myc and inducible nitric oxide (NO) synthase (iNOS) mRNA were observed by polymerase chain reaction (PCR) in the treated cells compared with the untreated ones. The increase in iNOS gene expression was associated with overproduction of NO. Moreover, the addition of 1 mmol L-1N-monomethyl-L-arginine, a structural analogue of arginine, reduced nitrite levels by about 70% in cells treated with captopril or pemphigus serum. Western blot analysis revealed an overexpression of heat shock protein 70 (hsp70) in cells treated with captopril or pemphigus serum. Finally, total inhibition of the keratinocyte transglutaminase gene was shown by PCR analysis in the same samples, compared with control cells. CONCLUSIONS: These data demonstrate the involvement of apoptosis in keratinocytes treated with captopril or pemphigus serum, with induction of the iNOS gene and hsp70 in the cascade of events leading to programmed cell death. PMID: 15214891 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 85: Toxicol Appl Pharmacol. 2004 Jul 1;198(1):11-20. Inhibition of cell cycle progression by penta-acetyl geniposide in rat C6 glioma cells. Chang YC, Chou FP, Huang HP, Hsu JD, Wang CJ. Institute of Biochemistry, College of Medicine, Chung Shan Medical University, Taichung, Taiwan. Penta-acetyl geniposide, (Ac)5-GP, the acetylated compound of geniposide, is able to inhibit the growth of rat C6 glioma cells in culture and in the bearing rats. Our recent data indicated that the induction of cell apoptosis and cell cycle arrest at G0/gap phase 1 (G1) by (Ac)5-GP might be associated with the induction of p53 and c-Myc, and mediated via the apoptosis-related bcl-2 family proteins. In this report, we further investigated the mechanism involved in the cell cycle arrest induced by (Ac)5-GP in C6 glioma cells. The inhibitory effect of (Ac)5-GP on the cell cycle progression of C6 glioma cells which arrested cells at the G0/G1 phase was associated with a marked decrease in the protein expression of cyclin D1, and an induction in the content of cyclin-dependent kinase (cdk) inhibitor p21 protein. This effect was correlated with the elevation in p53 levels. Further immunoprecipitation studies found that, in response to the treatment, the formation of cyclin D1/cdk 4 complex declined, preventing the phosphorylation of retinoblastoma (Rb) and the subsequent dissociation of Rb/E2F complex. These results illustrated that the apoptotic effect of (Ac)5-GP, arresting cells at the G0/G1 phase, was exerted by inducing the expression of p21 that, in turn, repressed the activity of cyclin D1/cdk 4 and the phosphorylation of Rb. PMID: 15207644 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 86: Int J Hyperthermia. 2004 Jun;20(4):405-19. Thermal enhancement of oxaliplatin-induced inhibition of cell proliferation and cell cycle progression in human carcinoma cell lines. Atallah D, Marsaud V, Radanyi C, Kornprobst M, Rouzier R, Elias D, Renoir JM. Pharmacologie Cellulaire et Moleculaire des Anticancereux, UMR CNRS 8612, 5 rue Jean-Baptiste Clement, F-92296 Chatenay-Malabry, France. Hyperthermia is used to treat intraperitoneal colorectal carcinomatosis. In this setting, the molecular effects of oxaliplatin and hyperthermia, in combination and alone, were deciphered in ovarian and colon cancer cells. The combined antiproliferative effects of hyperthermia and oxaliplatin (Eloxatine) on human IGROV-1 ovarian carcinoma, Caco-2 and HT-29 colon carcinoma cell lines were investigated by cell viability test, cell cycle analysis and modulation of expression of cell cycle-related proteins. Oxaliplatin inhibited growth of all cell lines in a dose-dependent manner. The efficacy of the drug was markedly enhanced by concurrent exposure to mild heat shock (1 h, 42 degree C). In IGROV-1 cells, a low concentration (15 microg/ml) of oxaliplatin in combination with hyperthermia induced a transient G2/M arrest. In both colon carcinoma cell lines, a G1/S arrest with a reduction of the G0/G1 population occurred. In IGROV-1 and Caco-2 cells, growth arrest was accompanied by apoptosis as suggested by the appearance of sub-G1 population. Time-course changes of cell cycle regulatory proteins levels revealed accumulation of cyclins A and B as well as of cdc2 and cdk2 upon exposure of IGROV-1 cells to hyperthermia and oxaliplatin. In this cell line, p53 appeared to be implicated in both G2/M arrest and apoptosis. G1/S arrest of HT-29 cells was linked to up-regulation of cyclin E and p27(Kip1) and accumulation of the hypophosphorylated form of pRB, whereas in Caco-2 cells only the hyperphosphorylated form was detected as well as a down-regulation of the proto-oncogene c-myc. Taken together, the results of these in vitro studies suggest that hyperthermia and oxaliplatin might elicit antiproliferative effects by modulating the expression of cell cycle regulatory proteins through different signalling pathways. PMID: 15204521 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 87: J Biol Chem. 2004 Aug 27;279(35):36698-707. Epub 2004 Jun 15. Myc-ARF (alternate reading frame) interaction inhibits the functions of Myc. Datta A, Nag A, Pan W, Hay N, Gartel AL, Colamonici O, Mori Y, Raychaudhuri P. Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, 900 S. Ashland Avenue, Chicago, IL 60607, USA. The tumor suppressor protein ARF (alternate reading frame) inhibits MDM2 to stabilize and activate the functions of p53. Here we provide evidence for an additional activity of ARF that attenuates cell cycle progression independently of p53 activation. We show that ARF interacts with c-Myc independently of MDM2 or p53. Consequently, ARF relocalizes c-Myc from the nucleoplasm to the nucleolus. Binding and relocalization by ARF correlate with an inhibition of the c-Myc-activated transcription in both p53-positive and -negative cells. Using inducible cell lines, we show that the wild type ARF, but not a mutant, inhibits expression of the c-Myc-induced genes before inhibiting S phase. Moreover, ARF inhibits Myc-induced progression into S phase in cells lacking p53 or expressing a defective p53, indicating that ARF inhibits the S phase stimulatory function of c-Myc independently of p53. Our results strongly suggest that cMyc is a bona fide target of ARF and that ARF attenuates c-Myc independently of the ARF-p53 axis. PMID: 15199070 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 88: Proc Natl Acad Sci U S A. 2004 Jun 22;101(25):9333-8. Epub 2004 Jun 10. Suppression of tumorigenesis by the p53 target PUMA. Hemann MT, Zilfou JT, Zhao Z, Burgess DJ, Hannon GJ, Lowe SW. Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA. The p53 tumor suppressor regulates diverse antiproliferative processes such that cells acquiring p53 mutations have impaired cell-cycle checkpoints, senescence, apoptosis, and genomic stability. Here, we use stable RNA interference to examine the role of PUMA, a p53 target gene and proapoptotic member of the Bcl2 family, in p53-mediated tumor suppression. PUMA short hairpin RNAs (shRNAs) efficiently suppressed PUMA expression and p53-dependent apoptosis but did not impair nonapoptotic functions of p53. Like p53 shRNAs, PUMA shRNAs promoted oncogenic transformation of primary murine fibroblasts by the E1A/ras oncogene combination and dramatically accelerated myc-induced lymphomagenesis without disrupting p53-dependent cell-cycle arrest. However, the ability of PUMA to execute p53 tumor suppressor functions was variable because, in contrast to p53 shRNAs, PUMA shRNAs were unable to cooperate with oncogenic ras in transformation. These results demonstrate that the p53 effector functions involved in tumor suppression are context dependent and, in some settings, depend heavily on the expression of a single proapoptotic effector. Additionally, they demonstrate the utility of RNA interference for evaluating putative tumor suppressor genes in vivo. PMID: 15192153 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 89: Nihon Kokyuki Gakkai Zasshi. 2004 May;42(5):378-86. [Molecular biology of lung cancer] [Article in Japanese] Akita H. Publication Types: Review Review, Tutorial PMID: 15168453 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 90: Anticancer Res. 2004 Mar-Apr;24(2A):465-71. Cellular models of drug- and radiation-resistant small cell lung cancer. Davey RA, Locke VL, Henness S, Harvie RM, Davey MW. Bill Walsh Cancer Research Laboratories, Royal North Shore Hospital, St Leonards NSW 2065, Australia. rdavey@med.usyd.edu.au BACKGROUND: The H69-EPR, H69-CP, H69-VP and H69/R38 resistant sublines of the classic small cell lung cancer (SCLC) line have proven useful in studies of resistance and its circumvention with paclitaxel. MATERIALS AND METHODS: The suppressor/oncogene profile of these sublines determined by Western and Northern blot was compared to the variant H82 SCLC cell profile. Two-dimensional electrophoresis/mass spectrometry was used to determine the effect of paclitaxel on protein expression. RESULTS: The H69-EPR and H69-CP resistant sublines were similar to the variant H82 cells for bcl-2, p21waf1, p53, N-myc and c-myc expression while the H69-VP subline retained the classic H69 pattern. A 1-h treatment with 10 ng/ml paclitaxel substantially reversed the resistance except for the H69/R38 subline and tended to reverse the resistance-associated changes in protein expression in the H69-EPR subline. CONCLUSION: Although some resistant sublines express a variant pattern of suppressor/oncogenes with low bcl-2, resistance is substantially reversed by paclitaxel treatment. PMID: 15152945 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 91: Cancer Res. 2004 May 15;64(10):3525-32. Somatic mutation of p53 leads to estrogen receptor alpha-positive and -negative mouse mammary tumors with high frequency of metastasis. Lin SC, Lee KF, Nikitin AY, Hilsenbeck SG, Cardiff RD, Li A, Kang KW, Frank SA, Lee WH, Lee EY. Departments of Developmental and Cell Biology, University of California, Irvine, California 92697, USA. Approximately 70% of human breast cancers are estrogen receptor alpha (ERalpha)-positive, but the origins of ERalpha-positive and -negative tumors remain unclear. Hormonal regulation of mammary gland development in mice is similar to that in humans; however, most mouse models produce only ERalpha-negative tumors. In addition, these mouse tumors metastasize at a low rate relative to human breast tumors. We report here that somatic mutations of p53 in mouse mammary epithelial cells using the Cre/loxP system leads to ERalpha-positive and -negative tumors. p53 inactivation under a constitutive active WAPCre(c) in prepubertal/pubertal mice, but not under MMTVCre in adult mice, leads to the development of ERalpha-positive tumors, suggesting that target cells or developmental stages can determine ERalpha status in mammary tumors. Importantly, these tumors have a high rate of metastasis. An inverse relationship between the number of targeted cells and median tumor latency was also observed. Median tumor latency reaches a plateau when targeted cell numbers exceed 20%, implying the existence of saturation kinetics for breast carcinogenesis. Genetic alterations commonly observed in human breast cancer including c-myc amplification and Her2/Neu/erbB2 activation were seen in these mouse tumors. Thus, this tumor system reproduces many important features of human breast cancer and provides tools for the study of the origins of ERalpha-positive and -negative breast tumors in mice. PMID: 15150107 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 92: Cancer Cell. 2004 May;5(5):501-12. Synthetic lethal targeting of MYC by activation of the DR5 death receptor pathway. Wang Y, Engels IH, Knee DA, Nasoff M, Deveraux QL, Quon KC. Department of Cancer Biology, Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121 USA. The genetic concept of synthetic lethality provides a framework for identifying genotype-selective anticancer agents. In this approach, changes in cellular physiology that arise as a consequence of oncogene activation or tumor suppressor gene loss, rather than oncoproteins themselves, are targeted to achieve tumor selectivity. Here we show that agonists of the TRAIL death receptor DR5 potently induce apoptosis in human cells overexpressing the MYC oncogene, both in vitro and as tumor xenografts in vivo. MYC sensitizes cells to DR5 in a p53-independent manner by upregulating DR5 cell surface levels and stimulating autocatalytic processing of procaspase-8. These results identify a novel mechanism by which MYC sensitizes cells to apoptosis and validate DR5 agonists as potential MYC-selective cancer therapeutics. PMID: 15144957 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 93: Cell Death Differ. 2004 Sep;11(9):1038-45. Omomyc expression in skin prevents Myc-induced papillomatosis. Soucek L, Nasi S, Evan GI. Cancer Research Institute, UCSF, San Francisco, CA 94143-0875, USA. lsoucek@cc.ucsf.edu Obligate sensitization to apoptosis provides a safeguard mechanism against the oncogenic potential of Myc. Omomyc is a mutant bHLHZip domain that sequesters Myc in complexes that are unable to bind to the E box recognition element and activate transcription but remain competent for transcriptional repression. Omomyc has the peculiar properties of reverting Myc-induced transformation of tissue culture cells and enhancing Myc proapoptotic function. Thus, Omomyc has the potential to act as a potent suppressor of Myc-induced oncogenesis. To validate the therapeutic potential of Omomyc in vivo, we targeted its expression to the adult suprabasal epidermis of Inv-c-MycER (TAM) transgenic mice which express a switchable form of the Myc protein in suprabasal cells. Activation of Myc induces rapid epidermal hyperplasia and papillomatosis. We show that Omomyc inhibits such Myc-induced papillomatosis, potentiating Myc-dependent apoptosis in a tissue in which it is usually strongly suppressed. Furthermore, Omomyc expression restores the normal keratinocyte differentiation program and skin architecture, both of which are otherwise disrupted by Myc activation. These findings indicate that it is possible to selectively enhance the intrinsic apoptotic pathway mediated by Myc and so quell its oncogenic action. PMID: 15143346 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 94: Cancer Lett. 2004 May 28;208(2):163-70. Induction of apoptosis in human lung cancer cells by curcumin. Radhakrishna Pillai G, Srivastava AS, Hassanein TI, Chauhan DP, Carrier E. Department of Medicine, Pediatrics and Family and Preventive Medicine, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0062, USA. Curcumin, a phenolic compound from the rhizome of the plant Curcuma longa has anti-inflammatory, antioxidant and anti-cancer activities. Although the precise mode of action of this compound is not yet elucidated, studies have shown that chemo-preventive action of curcumin might be due to its ability to induce apoptosis and to arrest cell cycle. This study investigated the cellular and molecular changes induced by curcumin leading to the induction of apoptosis in human lung cancer cell lines-A549 and H1299. A549 is p53 proficient and H1299 is p53 null mutant. The lung cancer cells were treated with curcumin (0-160 microM) for 12-72 h. Curcumin inhibited the growth of both the cell lines in a concentration dependent manner. Growth inhibition of H1299 cell lines was both time and concentration dependent. Curcumin induced apoptosis in both the lung cancer cell lines. A decrease in expression of p53, bcl-2, and bcl-X(L) was observed after 12 h exposure of 40 microM curcumin. Bak and Caspase genes remained unchanged up to 60 microM curcumin but showed decrease in expression levels at 80-160 microM. The data also suggest a p53 independent induction of apoptosis in lung cancer cells. PMID: 15142674 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 95: Biochem Pharmacol. 2004 Jun 1;67(11):2047-56. Induction of apoptosis in two human leukemia cell lines as well as differentiation in human promyelocytic cells by cyanidin-3-O-beta-glucopyranoside. Fimognari C, Berti F, Nusse M, Cantelli-Forti G, Hrelia P. Department of Pharmacology, University of Bologna, Via Irnerio 48, I-40126 Bologna, Italy. carmela.fimognari@unibo.it Little is known about the potentially chemopreventive mechanisms of anthocyanins apart from their antioxidant activity. We investigated the in vitro capacity of the anthocyanin cyanidin-3-O-beta-glucopyranoside (Cy-g) to induce apoptosis in T-lymphoblastoid, as well as apoptosis and differentiation in HL-60 promyelocytic cells. Although Cy-g-induced apoptosis (as well as necrosis) in the two systems, HL-60 cells were much less sensitive than T-lymphoblastoid cells. Moreover, treatment of HL-60 cells with Cy-g caused differentiation into macrophage-like cells and granulocytes. Concerning the mechanism of action, the induction of apoptosis in Jurkat T cells can be explained by a modulation of p53 and bax protein expression. At the molecular level, the induction of apoptosis and cytodifferentiation in HL-60 cells involved different proteins, thus suggesting that the effects of Cy-g on apoptosis and cytodifferentiation induction are two distinct events. These interesting biological properties should encourage further investigation into the chemopreventive and/or chemotherapeutic potential of Cy-g. PMID: 15135302 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 96: Bioelectromagnetics. 2004 May;25(4):296-307. High frequency electromagnetic fields (GSM signals) affect gene expression levels in tumor suppressor p53-deficient embryonic stem cells. Czyz J, Guan K, Zeng Q, Nikolova T, Meister A, Schonborn F, Schuderer J, Kuster N, Wobus AM. In Vitro Differentiation Group, Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany. Effects of electromagnetic fields (EMF) simulating exposure to the Global System for Mobile Communications (GSM) signals were studied using pluripotent embryonic stem (ES) cells in vitro. Wild-type ES cells and ES cells deficient for the tumor suppressor p53 were exposed to pulse modulated EMF at 1.71 GHz, lower end of the uplink band of GSM 1800, under standardized and controlled conditions, and transcripts of regulatory genes were analyzed during in vitro differentiation. Two dominant GSM modulation schemes (GSM-217 and GSM-Talk), which generate temporal changes between GSM-Basic (active during talking phases) and GSM-DTX (active during listening phases thus simulating a typical conversation), were applied to the cells at and below the basic safety limits for local exposures as defined for the general public by the International Commission on Nonionizing Radiation Protection (ICNIRP). GSM-217 EMF induced a significant upregulation of mRNA levels of the heat shock protein, hsp70 of p53-deficient ES cells differentiating in vitro, paralleled by a low and transient increase of c-jun, c-myc, and p21 levels in p53-deficient, but not in wild-type cells. No responses were observed in either cell type after EMF exposure to GSM-Talk applied at similar slot-averaged specific absorption rates (SAR), but at lower time-averaged SAR values. Cardiac differentiation and cell cycle characteristics were not affected in embryonic stem and embryonic carcinoma cells after exposure to GSM-217 EMF signals. Our data indicate that the genetic background determines cellular responses to GSM modulated EMF. Bioelectromagnetics 25:296-307, 2004. Copyright 2004 Wiley-Liss, Inc. PMID: 15114639 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 97: Oncogene. 2004 Apr 19;23(18):3230-47. The role of translation in neoplastic transformation from a pathologist's point of view. Rosenwald IB. Department of Pathology, Division of Hematopathology, University of New Mexico, BRF Building, Room 323 B, MSC08 4640, 1 University of New Mexico, Albuquerque, NM 87131, USA. irozenvald@salud.unm.edu Increased cell proliferation, which is a hallmark of aggressive malignant neoplasms, requires a general increase in protein synthesis and a specific increase in the synthesis of replication-promoting proteins. Transient increase in the general protein synthesis rate, as well as preferential translation of specific mRNAs coding for growth promoting proteins (e.g. cyclin D1), takes place during normal mitogenic response. A number of extensively studied growth signal transduction pathways (Ras, PI3K, MAPK, mTOR-dependent pathways) activate the function and expression of various components of the translational machinery. In abnormal situations, constitutive activation of signal transduction pathways (e.g. oncogenic activation of Ras or Myc) leads to continuous upregulation of key elements of translational machinery. On the other hand, tumor suppressor genes (p53, pRb) downregulate ribosomal and tRNA synthesis, and their inactivation results in uncontrolled production of these translational components. During recent years, a significant effort has been dedicated to determining whether expression of translation factors is increased in human tumors using clinical biopsy specimens. The results of these studies indicate that expression of particular translation initiation factors is not always increased in human neoplasms. The pattern of expression is characteristic for a particular tumor type. For example, eIF-4E is usually increased in bronchioloalveolar carcinomas but not in squamous cell carcinomas of the lung. Interestingly, in certain highly proliferative and aggressive neoplasms (e.g. squamous cell carcinoma of the lung, melanoma), the expression of eIF-4E is barely detectable. These findings suggest that mechanisms for increasing general protein synthesis in various neoplasms differ significantly. Finally, the possibility of qualitative alterations in the translational machinery, rather than a simple increase in the activity of its components, is discussed along with the possibility of targeting those qualitative differences for tumor therapy. Publication Types: Review Review, Tutorial PMID: 15094773 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 98: Oncogene. 2004 Apr 19;23(18):3208-16. RNA polymerase III transcription and cancer. White RJ. Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK. rwhite@udcf.gla.ac.uk RNA polymerase (pol) III synthesizes a range of essential products, including tRNA, 5S rRNA and 7SL RNA, which are required for protein synthesis and trafficking. High rates of pol III transcription are necessary for cells to sustain growth. A wide range of transformed and tumour cell types have been shown to express elevated levels of pol III products. This review will summarize what is known about the mechanisms responsible for this deregulation. Some transforming agents have been shown to stimulate expression of the pol III-specific transcription factors TFIIIB or TFIIIC2. In addition, TFIIIB is bound and activated by several oncogenic proteins, including c-Myc. Conversely, TFIIIB interacts in healthy cells with the tumour suppressors RB and p53. Indeed, the ability to limit pol III transcription through TFIIIB may contribute to their growth-suppression capacities. The function of p53 and/or RB is compromised in most if not all transformed cells; the resultant derepression of TFIIIB may provide an almost universal route to deregulate pol III transcription in cancers. In addition to effects on protein synthesis and growth, there is a precedent for a pol III product having oncogenic activity. Publication Types: Review Review, Tutorial PMID: 15094770 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 99: Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):6164-9. Epub 2004 Apr 12. Bim is a suppressor of Myc-induced mouse B cell leukemia. Egle A, Harris AW, Bouillet P, Cory S. The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Melbourne, Victoria 3050, Australia. Impaired apoptosis is now recognized to be central to tumor development. Bcl2, activated by chromosomal translocation in human follicular lymphoma, promotes oncogenesis by inhibiting apoptosis. Bim, a distant proapoptotic relative, is emerging as a major physiologic antagonist of Bcl2. Here, we show that loss of Bim is oncogenic. Bim protein levels were elevated in the apoptosis-prone B lymphoid cells of Emicro-Myc-transgenic mice, and Bim-mutant Emicro-Myc mice had increased numbers of IgM-bearing B cells. Emicro-Myc-expressing B lymphoid cells deficient in Bim were refractory to apoptosis induced in vitro by cytokine deprivation or antigen receptor cross-linking. Thus, Bim is induced by Myc in B cells and mediates apoptosis. Remarkably, inactivation of even a single allele of Bim accelerated Myc-induced development of tumors, particularly acute B cell leukemia. None of the primary tumors from Bim(+/-) Emicro-Myc mice displayed loss of the second allele of Bim. These findings indicate that Bim is a tumor suppressor, at least in B lymphocytes, and is haploinsufficient. Whereas the p19Arf/p53 pathway is frequently mutated in tumors arising in Bim(+/+) Emicro-Myc mice, it was unaffected in most Bim-deficient tumors, indicating that Bim reduction is an effective alternative to loss of p53 function. PMID: 15079075 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 100: Oncogene. 2004 Jun 17;23(28):4847-55. Cyr61 suppresses the growth of non-small-cell lung cancer cells via the beta-catenin-c-myc-p53 pathway. Tong X, O'Kelly J, Xie D, Mori A, Lemp N, McKenna R, Miller CW, Koeffler HP. Division of Hematology/Oncology, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA 90048, USA. Cysteine-rich protein 61 (Cyr61) is a growth factor-inducible, immediate-early gene that has multifaceted activities in various cancers. In a previous study, we found that Cyr61 inhibited the growth of the H520 and H460 non-small-cell lung cancer (NSCLC) cell lines. In further studies, we now report that p53 plays a pivotal role in Cyr61-dependent cellular growth arrest. Blocking Cyr61 with a Cyr61 antibody resulted in the downregulation of expression of p53 and p21, as well as partially reversing the growth suppression of H520-Cyr61 cells. Proliferation of NSCLC cell lines (NCI-H157, H125, H1299), having a mutant p53, were not suppressed by Cyr61. Inhibition of wild-type p53, by either human papilloma virus type 16 E6 or a dominant-negative p53, resulted in the rescue of the growth suppression mediated by Cyr61 in the H520-Cyr61 cells. The enhanced levels of p21WAF1 and p130/RB2, in the Cyr61-expressing H520-Cyr61 cells, were also inhibited by blocking p53 showing that p21 and p130 were induced by p53 in these cells. In addition, levels of both c-myc and beta-catenin increased in Cyr61 stably transfected H520 cells. Moreover, beta-catenin was translocated into the nucleus in these cells. Inhibition of c-myc expression in the H520-Cyr61 cells with antisense c-myc resulted in their decreased levels of p53. Transfecting cells with a dominant-negative T-cell factor (TCF4), the specific inhibitor of the beta-catenin/TCF4 complex, downregulated the expression of c-myc. Taken together, the data suggest that Cyr61 suppressed the growth of NSCLC cells by triggering a signal transduction pathway through beta-catenin. In this pathway, Cyr61 activated the beta-catenin/TCF4 complex, which promoted the expression of c-myc and the latter induced expression of p53, and p53 upregulated p21WAF1 and p130/RB2, resulting in growth arrest. Copyright 2004 Nature Publishing Group PMID: 15077166 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 101: Zhongguo Yi Xue Ke Xue Yuan Xue Bao. 2004 Feb;26(1):79-82. [Recent advances in gene change of pancreatic cancer] [Article in Chinese] Wang YY, Cui QC. Department of Pathology, PUMC Hospital, CAMS and PUMC, Beijing 100730, China. wangyuyue2002@yahoo.com A large number of data derived from molecular analyses support the hypothesis that human cancer is a genetic disease and a distinct subset of genes have been found to be genetically changed in most tumors. Molecular alterations in pancreatic cancer include: (1) oncogenes such as K-ras, c-myc, c-fos, and c-erbB-2; (2) tumor suppressor genes such as p53, p16, DPC4/SMAD4, and DCC; and (3) growth factors such as EGF, FGF, HGF, PDGF, VEGF, TGF-beta. Genetic alterations of K-ras and p53 are common in human pancreatic cancer, but the occurrence of pancreatic cancer is a multi-step phenomenon in which the accumulation of genetic changes is extremely important. Publication Types: Review Review, Tutorial PMID: 15052782 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 102: Cell Cycle. 2004 May;3(5):611-5. Epub 2004 May 9. The significance of p16INK4a in cell defenses against transformation. Drayton S, Brookes S, Rowe J, Peters G. Cancer Research United Kingdom, London Research Institute, UK. Human cells, including fibroblast strains that have been immortalized by telomerase, are much more resistant to transformation than rodent cells. Most of the experimental evidence suggests that transformation of human fibroblasts requires inactivation of both the retinoblastoma (pRb) and p53 tumor suppressors as well as the addition of one or more dominant oncogenes. By starting with strains of primary fibroblast (Leiden and Q34 cells) that are genetically deficient for p16INK4a, we have been able to generate anchorage independent colonies simply by addition of telomerase (hTERT) and either Ras or Myc. Importantly, the transformed cells appear to retain pRb and p53 functions and are essentially diploid. Whereas Leiden cells expressing the individual oncogenes did not form tumors in mice, the combination of hTERT, Myc and Ras enabled them to become tumorigenic, albeit at a frequency suggestive of an additional genetic event. Significantly, we have obtained karyotypically stable tumors without the need to use DNA tumor virus oncoproteins and without deliberate ablation of p53. Publication Types: Review Review, Tutorial PMID: 15044857 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 103: Cancer Genet Cytogenet. 2004 Mar;149(2):154-60. Molecular cytogenetic parameters in fibroblasts from patients and carriers of xeroderma pigmentosum. Amiel A, Peretz G, Slor H, Weinstein G, Fejgin MD. Sackler School of Medicine, Tel-Aviv University, Ramat Aviv 69978, Israel. Amiel.Aliza@clalit.org.il Xeroderma pigmentosum (XP) is a rare autosomal recessive syndrome. Laboratory investigations have failed to detect any consistent anomaly in cells from XP heterozygotic subjects, although examples of behavior intermediate between normal and XP cells have been reported. To estimate random aneuploidy we applied fluorescence in situ hybridization (FISH) with alpha-satellite probes for chromosomes 8 and 9 and replication pattern for TP53 (p53), ERBB2 (HER-2/neu), and MYCN (N-MYC) loci and for the imprinted SNRPN locus. A significantly higher rate of aneuploidy rate was observed in XP patients and carriers than in controls. The asynchrony pattern was significantly higher in XP carriers and patients with all three coding loci analyzed and significantly lower in XP patients and carriers with the imprinted locus SNRPN than in the control group. Molecular cytogenetic parameters such as random aneuploidy and replication pattern, which are known to reflect chromosomal instability, may be part of the tumorigenesis process. In XP patients and carriers, this genetic instability may represent a potential for developing malignancies. PMID: 15036891 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 104: J Cell Biochem. 2004 Apr 1;91(5):973-86. Inhibition of AP-1 transcription activator induces myc-dependent apoptosis in HL60 cells. Park S, Hahm ER, Lee DK, Yang CH. School of Chemistry and Molecular Engineering, Seoul National University, Seoul 151-742, Korea. Transcriptional activation of AP-1 is intricately involved in cell proliferation and transformation. The natural product, nordihydroguaiaretic acid (NDGA) shows an inhibitory effect on the binding of jun/AP-1 protein to the AP-1 site in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated HL60 cells. The NDGA inhibits the auto-regulated de novo synthesis of c-jun mRNA in TPA-stimulated HL60 cells. Our data also determine that this compound induces proliferation inhibition and apoptosis in human leukemia HL60 cells. To obtain information on the functional role of the AP-1 inhibition by NDGA in apoptosis signaling, the effects of pharmacological inhibition of AP-1 binding on c-myc, p53, and bax protein level were determined. Our results indicate that treatment of cells with NDGA enhances c-myc, p53, and bax protein levels. To rule out the possibility that NDGA will induce apoptosis because of the effects on proteins other than AP-1, we investigated the effect of another AP-1 inhibitor, SP600125, which is specific to Jun-N-terminal kinase. SP600125 decreased not only the phosphorylation level of jun protein but also AP-1/DNA binding activity. Also, apoptosis was observed to be induced by SP600125, concomitant with the increase in c-myc, p53, and bax protein level. In addition, apoptosis induced by both AP-1 inhibitors was accompanied by the activation of a downstream apoptotic cascade such as caspase 9, caspase 3, and poly[ADP-ribose]polymerase (PARP). When the cells were treated with NDGA or SP600125 in the presence of antisense c-myc oligonucleotides, apoptosis was not observed and an increase of c-myc, p53, and bax proteins was not manifested. All these results show that the inhibition of the transcription factor AP-1 action is related with either the drug-induced apoptosis or the drug toxicity of the HL60 cells. The apoptosis induced by AP-1 inhibition may be dependent on c-myc protein levels suggesting that the c-myc protein induces apoptosis at a low level of AP-1 binding activity. Altogether, our findings suggest that the presence of the AP-1 signal acts as a survival factor that determines the outcome of myc-induced proliferation or apoptosis. Copyright 2004 Wiley-Liss, Inc. PMID: 15034932 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 105: Ai Zheng. 2004 Mar;23(3):273-7. [Expression and significance of telomerase reverse transcriptase and its regulators in non-small cell lung carcinoma] [Article in Chinese] Chen TX, Xiong YY, Liu L. Department of Pathology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430071, PR China. chentaoxiang@sohu.com BACKGROUND & OBJECTIVE: Telomerase is a ribonucleoprotein complex, which is silent in normal human somatic cells but may be reactivated by a series of regulators, and cause tumorigenesis. As a critical factor of telomerase activity, much progression has been achieved in the study of regulation of human telomerase reverse transcriptase, but the detail mechanism is still not clear. This study was designed to investigate the relationship of expression of human telomerase reverse transcriptase mRNA (hTERT mRNA) and its regulators including c-myc, mutant p53, protein kinase C alpha (PKCalpha) with clinicopathological significance of expression of the four markers in non-small cell lung carcinoma (NSCLC). METHODS: The expression of hTERT mRNA in 113 NSCLC specimens were detected by in situ hybridization, and the expression of c-myc, mutant p53, and PKCalpha in the same specimens were detected by immunohistochemistry. RESULTS: The positive rates of 113 NSCLC samples for hTERT mRNA, c-myc, mutant p53, and PKCalpha were 80.5%, 68.1%, 61.9%, and 85.0%, respectively. The differences were statistically significant among the expression of hTERT mRNA, c-myc, and PKCalpha (P< 0.05 or P< 0.01), but was not significant between the expression of mutant p53 and hTERT mRNA, c-myc as well as PKCalpha. The expression of mutant p53 was associated with carcinoma cell differentiation (P< 0.05), and its positive rate gradually increased with the extend of differentiation of carcinoma cell. The expression of hTERT mRNA, c-myc, and PKCalpha were not associated with carcinoma cell differentiation. There was no relationship of expression of the four markers with histological types, TNM stages, and lymph node metastasis status. CONCLUSION: C-myc and PKCalphawere associated with the expression of telomerase. PMID: 15025956 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 106: Ai Zheng. 2004 Mar;23(3):235-42. Circadian expression of dihydropyrimidine dehydrogenase, thymidylate synthase, c-myc and p53 mRNA in mouse liver tissue. Wu MW, Xian LJ, Li XM, Pasquale I, Francis L. INSERM E 0354 Chronotherape utique des cancers, Hopital Paul Brousse and Universite Paris XI, 94807 Villejuif Cedex, France. BACKGROUND & OBJECTIVE: Anti-cancer effect of 5-Fluorouracil (5-FU) is mediated mainly by inhibition of the thymidylate synthase (TS), while dihydropyrimidine dehydrogenase (DPD) is an initial and a rate-limiting catabolic enzyme of 5-FU. In this study, the mRNA expression profiles of TS, DPD, p53 and c-myc were investigated in mouse liver. METHODS: A total of 24 male B6D2F1 mice were involved in this study. All the mice were synchronized with an alternation of 12 h of light (L) and 12 h of darkness (D) (LD12:12) for 4 weeks. Body temperature and rest-activity were monitored with an intra-peritoneal sensor. All the mice were sacrificed at 3, 7, 11, 15, 19, 23 HALO (hours after light onset) respectively and liver samples were obtained and immediately frozen in liquid nitrogen. Total RNA was extracted from the frozen liver samples and one-step real-time quantitive RT-PCR was performed using LightCycler - RNA Amplification Kit SYBR Green I system. RESULTS: Both body temperature and rest-activity displayed similarly rhythmic patterns with peak times located in darkness, while the trough time was located in the light span. DPD showed a circadian expression in mRNA level with a peak at about 16 HALO (P=0.0012). TS showed a trend for a circadian rhythm, with a peak during light (P=0.079). Neither c-myc nor p53 displayed significant circadian rhythm. CONCLUSION: The 24-h patterns in DPD and TS expression were approximately 12 h out of phase, supporting a coordinated regulation of both transcriptional pathways relevant for 5-FU chronopharmacology. PMID: 15025949 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 107: Hum Pathol. 2004 Mar;35(3):328-34. Immunohistochemical evaluation of adenomatous polyposis coli, beta-catenin, c-Myc, cyclin D1, p53, and retinoblastoma protein expression in syndromic and sporadic fundic gland polyps. Hassan A, Yerian LM, Kuan SF, Xiao SY, Hart J, Wang HL. Lauren V Ackerman Laboratory of Surgical Pathology, Washington University, St. Louis, MO 63110-1093, USA. Syndromic and sporadic fundic gland polyps are morphologically indistinguishable but may arise via different pathogenetic mechanisms involving mutations of the adenomatous polyposis coli (APC) and its downstream target beta-catenin genes. Although a higher frequency of dysplasia has been reported in syndromic forms, the risk of developing invasive carcinoma is exceedingly low. The current study was designed to investigate whether syndromic and sporadic fundic gland polyps differ in protein expression of a number of genes that are thought to be important in the control of neoplastic transformation. A total of 262 fundic gland polyps, including 155 syndromic polyps obtained from 35 patients with familial adenomatous polyposis or Gardner's syndrome and 107 sporadic polyps randomly selected from 45 patients with gastroesophageal reflux disease or Barrett's esophagus, were included in this study. Immunohistochemical evaluation showed that loss of immunoreactivity to the antibody against the carboxyl terminus of the APC protein, presumably resulting from APC gene mutations, was more frequent in syndromic than in sporadic cases (40% versus 6.7%, P<0.001). However, immunostaining failed to show aberrant nuclear localization of beta-catenin, a protein regulated by APC, in any of the polyps, irrespective of syndromic or sporadic types. Instead, positive membranous staining for beta-catenin was observed in all the cases. In addition, the expression characteristics of 2 other proteins, c-Myc and cyclin D1, whose genes have been reported to be transcriptionally regulated by the APC/beta-catenin pathway, were similar in these two types of polyps. Furthermore, all cases, including those harboring dysplasia, showed negative nuclear staining for p53 and positive nuclear staining for retinoblastoma (RB). Taken together, these data show a lack of dysregulation in the APC/beta-catenin signaling pathway and in the expression of p53 and RB in fundic gland polyps despite a high frequency of somatic mutations of the APC and beta-catenin genes reported in these polyps. These findings may explain at least in part why fundic gland polyps show a negligible malignant potential even in the presence of dysplasia. PMID: 15017589 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 108: Cancer Cell. 2004 Feb;5(2):177-89. Loss of CBP causes T cell lymphomagenesis in synergy with p27Kip1 insufficiency. Kang-Decker N, Tong C, Boussouar F, Baker DJ, Xu W, Leontovich AA, Taylor WR, Brindle PK, van Deursen JM. Department of Pediatric and Adolescent Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. CBP can function as a tumor suppressor, but the mechanisms that govern oncogenesis in its absence are unknown. Here we show that CBP inactivation in mouse thymocytes leads to lymphoma. Although CBP has been implicated in the transactivation functions of p53, development of these tumors does not seem to involve loss of p53 activity. CBP-null tumors show reduced levels of p27Kip1 and increased levels of cyclin E and Skp2, two oncoproteins that can promote p27Kip1 proteolysis. Reduction of p27Kip1 by introduction of a p27Kip1-null allele into CBP knockout mice accelerates lymphomagenesis and seems to obviate the requirement for Skp2 and cyclin E upregulation. These data suggest that CBP loss mediates lymphomagenesis in cooperation with a mechanism that reduces p27Kip1 abundance. PMID: 14998493 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 109: Proc Natl Acad Sci U S A. 2004 Mar 9;101(10):3456-61. Epub 2004 Feb 27. Identification of p53 regulators by genome-wide functional analysis. Huang Q, Raya A, DeJesus P, Chao SH, Quon KC, Caldwell JS, Chanda SK, Izpisua-Belmonte JC, Schultz PG. Department of Chemistry, The Scripps Research Institute, Mail Stop SR202, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA. The p53 tumor-suppressor protein is a critical mediator of cellular growth arrest and the induction of apoptosis. To identify proteins involved in the modulation of p53 transcriptional activity, a gain-of-function cellular screen was carried out with an arrayed matrix of approximately 20,000 cDNAs. Nine genes previously unknown to be involved in regulating p53 activity were identified. Overexpression of seven of these genes (Hey1, Hes1, TFAP4, Osr1, NR2F2, SFRS10, and FLJ11339) resulted in up-regulation of p53 activity; overexpression of two genes (M17S2 and cathepsin B) resulted in down-regulation of p53 activity in mammalian cells. HES1, HEY1, and TFAP4, which are members of the basic helix-loop-helix transcription family, and OSR1 were shown to activate p53 through repression of HDM2 transcription. Ectopic expression of these basic helix-loop-helix transcription factors in both zebrafish and avian developmental systems activated p53 and induced apoptosis in vivo, resulting in a phenotype similar to that of p53 overexpression. Furthermore, ras- and myc-mediated transformation of mouse embryonic fibroblasts was abrogated by expression of HEY1 in a p53-dependent manner. These results suggest that these transcription factors are members of an evolutionarily conserved network that governs p53 function. PMID: 14990790 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 110: Proc Natl Acad Sci U S A. 2004 Feb 24;101(8):2410-5. Artemis and p53 cooperate to suppress oncogenic N-myc amplification in progenitor B cells. Rooney S, Sekiguchi J, Whitlow S, Eckersdorff M, Manis JP, Lee C, Ferguson DO, Alt FW. Howard Hughes Medical Institute, Children's Hospital, Department of Genetics, Harvard Medical School, and Center for Blood Research, Boston, MA 02115, USA. The nonhomologous DNA end-joining (NHEJ) pathway contains six known components, including Artemis, a nuclease mutated in a subset of human severe combined immunodeficient patients. Mice doubly deficient for the five previously analyzed NHEJ factors and p53 inevitably develop progenitor B lymphomas harboring der(12)t(12;15) translocations and immunoglobin heavy chain (IgH)/c-myc coamplification mediated by a breakage-fusion-bridge mechanism. In this report, we show that Artemis/p53-deficient mice also succumb reproducibly to progenitor B cell tumors, demonstrating that Artemis is a tumor suppressor in mice. However, the majority of Artemis/p53-deficient tumors lacked der(12)t(12;15) translocations and c-myc amplification and instead coamplified IgH and N-myc through an intra- or interchromosome 12 breakage-fusion-bridge mechanism. We discuss this finding in the context of potential implications for mechanisms that may target IgH locus translocations to particular oncogenes. PMID: 14983023 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 111: Anticancer Res. 2003 Nov-Dec;23(6C):4831-5. Early effects of different cytostatic protocols for head and neck cancer on oncogene activation in animal experiments. Nemeth A, Nadasi E, Gyongyi Z, Olasz L, Nyarady Z, Ember A, Kvarda A, Bujdoso L, Arany I, Kiss I, Csejtey I, Ember I. Dept. of Public Health, Faculty of Medicine, University of Pecs, H-7643 Szigeti u. 12, Hungary. arpadnemeth@freemail.hu In vivo investigations on oncogenes and onco-suppressor genes may provide new findings on the potential carcinogenic effects of various cytostatic protocols inducing secondary tumours of the head and neck. Further surgeries are often necessary due to regional recurrence after the Cisplatin-supplemented BVM (Bleomycin, Vincristine, Methotrexate) protocol in the treatment of human head and neck tumours. Our earlier studies have illustrated the carcinogenic and mutagenic potential of Cisplatin. The effect of Cisplatin on the alteration of different onco- and suppressor genes has also been proven. Our present study aimed at investigating the early effects of the BVM and the CFu (Cisplatin, 5-Fluorouracil) protocols on early oncogene and tumour suppressor gene expressions in mice. Body weight equivalent amounts of cytostatics were administered intraperitoneally to 6- to 8-week-old, inbred, female CBA/Ca mice. Twenty-four, 48 and 72 hours after the treatment, RNA was isolated from the target organs and the quantitative expression of c-myc, Ha-ras and p53 genes were examined. The protocols caused detectable changes. A "short-term" in vivo test, the 24-hour examination of gene expression, is suitable for detecting early effects of carcinogen exposure. The alterations of gene expression, caused by the Cisplatin-containing protocol, draw attention to the probable role of Cisplatin in the development of regional recurrence and to the possibility of prevention. PMID: 14981932 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 112: Leukemia. 2004 Apr;18(4):720-6. Expression of the p14ARF tumor suppressor predicts survival in acute myeloid leukemia. Muller-Tidow C, Metzelder SK, Buerger H, Packeisen J, Ganser A, Heil G, Kugler K, Adiguzel G, Schwable J, Steffen B, Ludwig WD, Heinecke A, Buchner T, Berdel WE, Serve H. Department of Internal Medicine, Hematology and Oncology, University of Munster and the AMLCG study group, Munster, Germany. muellerc@uni-muenster.de Cell cycle aberrations are associated with therapy outcome in many types of cancer. We analyzed mRNA expression levels of 18 cell cycle-related genes in bone marrow samples from 78 acute myeloid leukemia (AML) patients and six controls using high-throughput quantitative RT-PCR. Samples of AML patients contained significantly increased mRNA expression levels of the mdm2 and c-myc oncogenes. Also, the average expression levels of p14ARF and p16INK4A were higher in patient samples compared to controls. Leukemic blasts and control bone marrow samples did not differ significantly in the expression levels of proliferation-associated genes such as cyclin A2 and pcna. When single genes were analyzed for prognostic significance in Kaplan-Meier and Cox regression analyses, a low p14ARF level emerged as a strong and independent predictor for poor survival (P=0.04 and 0.029). Subsequently, p14ARF mRNA levels were analyzed in a second, independent patient population (n=57). Again, low p14ARF levels were associated with a worse outcome. Finally, immunohistochemistry analysis of AML tissue arrays confirmed the widespread expression of c-myc and p14ARF in AML on the protein level. Taken together, the expression of the p53 regulators mdm2 and p14ARF are altered in AML, and low p14ARF levels indicate a poor prognosis. PMID: 14973498 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 113: Beijing Da Xue Xue Bao. 2004 Feb;36(1):61-5. [Human telomerase P53 estrogen and progesterone receptor expression in endometrial carcinoma] [Article in Chinese] Dong Y, Li T, Liang Y, Zou WZ. Department of Pathology, Peking University First Hospital, Beijing 100034, China. ying_dg@263.net OBJECTIVE: To study the role of hTERT and c-myc,P53,ER,PR in endometrial carcinoma carcinogenesis. METHODS: The expression of hTERT, c-myc mRNA, P53 protein, ER and PR examined by in situ hybridization and immunohistochemistry in 14 cases of endometrial simple hyperplasia, 10 of complex hyperplasia, 8 of atypical hyperplasia and 52 with endometrial carcinoma. RESULTS: (1) The positive rate of hTERT in simple, complex, atypical hyperplasia and carcinoma were 14.3% (2/14), 50.0% (4/8), 80.0% (8/10) and 92.3% (48/52), respectively. The prevalence and intensity of hTERT signal were greater in the carcinomas and atypical hyperplasia than those in simple or complex hyperplasia (P<0.05). The expressions of c-myc and P53 were similar to that of hTERT. (2) The expressions of hTERT, c-myc, P53 and PR were significantly correlated with tumor differentiation. The expressions of c-myc and P53 in type I were significantly different from those in type II. The expression of c-myc with lymph node metastasis was significantly higher than that without metastasis. (3) The positive correlation between hTERT and c-myc was found in endometrial carcinoma (r=0.398 8, P<0.05); It was also found between hTERT and P53 in type II endometrial carcinoma (r=1.000, P<0.05). CONCLUSION: The expressions of hTERT, c-myc and P53 may be involved in the progression from the endometrial atypical hyperplasia to cancer. They may also be associated with the prognosis of endometrial carcinoma. c-myc and P53 may play a role in the transcriptive activation of hTERT gene in endometrial carcinoma. PMID: 14970891 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 114: Oncol Rep. 2004 Mar;11(3):647-54. The multistage process of carcinogenesis in human esophageal epithelial cells induced by human papillomavirus. Shen ZY, Xu LY, Li EM, Cai WJ, Shen J, Chen MH, Cen S, Tsao SW, Zeng Y. Department of Pathology, Medicine College of Shantou University, Shantou 515031, PR China. zhongyingshen@yahoo.com To investigate the multistage process of carcinogenesis, the progressive alteration of the morphology, telomerase, cytogenesis, oncogenes and tumorigenicity in the process of immortalization and malignant transformation of the human fetal esophageal epithelial cell (SHEE) was studied. The SHEE cells were immortalized by gene E6E7 of human papilloma virus (HPV) type 18 in our laboratory and continually cultivated over 100 passages, which had been malignantly transformed. Cells at the 11th, 35th, 65th and 100th passage were examined according to the following criteria: morphological changes of cell growth, contact-inhibition and anchorage-independent growth (AIG); the cell proliferative and apoptotic index; the modal number of chromosomes; c-myc, p53, bcl-2, ras; telomere length and activities of telomerase and tumorigenicity in nude mice or severe combined immunodeficient (SCID) mice. The cells of the 11th passage were well differentiated and the cells of 100th passage were relatively poorly differentiated with polymorphism, while the cells of 35th and 65th had two distinct differentiations. The proliferative indexes were 21.1%, 32.5%, 33.2%, and 40.9% and the apoptotic indexes were 3.3%, 2.7%, 3.5%, 2.7% in the 11th, 35th, 65th and 100th passage respectively. Karyotypes of four cell passages belonged to hyperdiploidy and hypotriploidy. C-myc, ras, p53 genes were low in the 10th and 35th, and high in the 65th and 100th passage, but bcl-2 was low in 4 passages. Telomere length sharply decreased from normal fetal esophagus cells until the 35th passage, but it was stably expressed in the 65th and 100th passage. The activities of telomerase were expressed in cells of the 35th, 65th and 100th passages. The efficiency of AIG varied in different passages of the SHEE cell and was absent in the 11th passage, low efficiency in the 35th passage and 65th passage, and high efficiency in the 100th passage. Transplanted cells of the 65th and 100th passage into SCID mice resulted in tumor formation, but only the 100th passage cells could grow in nude mice. All of these characteristic changes were in dynamic progressive process. These data demonstrate that carcinogenesis of esophageal epithelial cells induced by HPV is the multistage process, which goes through the initial, immortal, premalignant and malignant transformation stages. The generation of esophageal carcinoma is caused by the accumulation of cellular, genetic and molecular changes. PMID: 14767516 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 115: Acta Neurochir Suppl. 2003;86:507-11. Tissue reconstruction process in the area of peri-tumoural oedema caused by glioblastoma--immunohistochemical and graphical analysis using brain obtained at autopsy. Nagashima G, Suzuki R, Asai JI, Noda M, Fujimoto M, Fujimoto T. Department of Neurosurgery, Showa University, Fujigaoka Hospital, Fujigaoka, Aoba-ku, Yokohama-shi, Kanagawa-ken, Japan. goro-n@po1.dti2.ne.jp BACKGROUND: In the area of peri-tumoural oedema, proteolytic agents derived from the tumour cause tissue degradation, which promotes tumour cell invasion. METHOD: We investigated the biological processes in the area of peri-tumoural oedema, using a brain obtained at autopsy from a patient who died from glioblastoma. Immunohistochemistry was performed to detect vascular endothelial growth factor (VEGF), c-myc, p53, paternally expressed gene-3 (PEG-3), transforming growth factor beta (TGFB), and tumour necrosis factor alpha (TNFA). The data were translated into colour graphics and the localization of these proteins was analyzed. FINDINGS: In the area of peri-tumoural oedema, Ki-67 and p53 positive cells were observed with TGFB expression. Moreover, c-myc, PEG-3, VEGF, and TNFA were also expressed strongly in the glial cells or extra-cellular spaces in the area of peri-tumoural oedema. INTERPRETATION: These data suggest that in the area of peri-tumoural oedema, tissue reconstruction processes take place with concomitant anti-tumour activities. The expression of c-myc, VEGF, and TNFA in the area of peri-tumoural oedema may indicate that these proteins are not utilized for tumour growth, but may be used to guard the brain against tumour invasion. Peri-tumoural oedema does not only indicate the tissue damage caused by tumour, but many tissue reconstruction processes take place in these areas against tumour cell invasion. Publication Types: Case Reports PMID: 14753496 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 116: Arch Virol. 2004 Feb;149(2):323-36. Epub 2003 Sep 22. HCV core, NS3, NS5A and NS5B proteins modulate cell proliferation independently from p53 expression in hepatocarcinoma cell lines. Siavoshian S, Abraham JD, Kieny MP, Schuster C. INSERM U544, Strasbourg, France. Several reports have shown that activity and/or expression of p53 can be modulated by Hepatitis C virus (HCV) proteins and may interfere with normal regulation of cell growth. In order to understand the relationship between p53 function and HCV proteins expression, we have investigated potential effects of the core, NS3, NS5A and NS5B proteins on Huh-7 (p53 +/+) and Hep3B (p53 -/-) cell proliferation. The effect of HCV proteins transiently expressed after recombinant-adenoviral infection was analyzed by Western blot, crystal violet and propidium iodide staining. Expression of the core, NS3, NS5A or NS5B proteins inhibited cell proliferation and blocked both cell lines in the G2/M phase of the cell cycle. c-myc and p53 expression were respectively induced and increased in Huh-7 cells only following expression of the Core protein. No expression of p21(waf1/cip1) could be detected and expression of cyclin A, cdk2 and p27(Kip1) were independent of HCV protein's expression. Our results show that the effect of core, NS3, NS5A and NS5B on cell proliferation is independent of p53 expression and that only the Core protein, induces the expression of both c-myc and p53. PMID: 14745598 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 117: Izv Akad Nauk Ser Biol. 2003 Sep-Oct;(5):534-41. [Endogenous DNases as a tool for isolation of nuclear matrix: critical parameters of nucleolysis] [Article in Russian] Borisova NP, Kostiuk GV, Shevchenko NA, Boikov PIa, Rudakova EV, Papina RI, Terent'ev AA. Institute of Problems of Chemical Physics, Russian Academy of Sciences, prosp. Akad. Semenova 4, Chernogolovka, Moscow Region, 142432 Russia. Degree of nucleolysis has critical significance for isolation of nuclear matrix (NM) specifically enriched in transcribed DNA sequences as demonstrated at the example of inactive (c-fos, c-myc, and Ck) and active (p53, albumin, and 28S rRNA) genes in resting hepatocytes. Optimal degree of nucleolysis features degradation of loop domains of chromatin with preserved relatively uniform molecular weight distribution of DNA. Deviation from these parameters leads to nonspecific fragmentation of chromatin in various gene loci and isolation of NM samples nonspecifically enriched or depleted of transcribed DNA sequences. Under optimal hydrolytic conditions, the transcribed chromatin is more resistant to endogenous DNase attack, which allows selective conservation of its association with the nuclear matrix. PMID: 14735782 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 118: J Cardiovasc Surg (Torino). 2003 Oct;44(5):577-82. Apoptotic cell death and genetic control in graft coronary artery disease in heart transplant. Di Stefano S, Pardo J, Panizo A, Herreros J, Tamayo E, Florez S, Fulquet E, Echevarria JR, Carrascal Y, Fiz L. Department of Cardiac Surgery, University Hospital,Valladolid, Spain. sdst@atenet.edu AIM: Apoptosis is a type of programmed cell death whereby, immunologic, genetic and biochemical mechanisms are involved in its control. On the other hand, graft coronary artery disease is the most important restrictive factor for the long-term survival of heart transplantation. The purpose of this study is to analyse both apoptotic cell lesions in transplanted patients that present coronary artery disease. METHODS: From August 1984 until December 1996, 148 heart transplants were carried out in the Clinica Universitaria de Navarra. In 102 patients, annual coronary angiography was performed, reaching a diagnosis of coronary artery disease in 30 patients. Study of apoptotic cell death was done in the tissue of endomyocardial biopsies on all patients by means of the TUNEL technique. Procedures of immunohistochemistry with antibodies antic-myc, p53 and bcl-2 were carried out and results were compared with a control group of 30 patients with homogeneous characteristics. RESULTS: All patients with coronary artery disease showed apoptotic cardiomyocytes, 13 patients to a mild degree, 14 to a moderate degree and 3 to a severe degree, while in the control group apoptosis was found only to a mild degree in 8 patients, obtaining a very significant statistical difference (p<0.0001). The expression of analysed oncoproteins was null in the 2 groups. CONCLUSION: Myocardial apoptosis is a constant finding in transplanted patients with coronary artery disease. We have not seen any correlation between the apoptotic process and genetic mechanisms. PMID: 14735044 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 119: Cancer Res. 2004 Jan 1;64(1):55-63. Identification of a gene expression signature associated with recurrent disease in squamous cell carcinoma of the head and neck. Ginos MA, Page GP, Michalowicz BS, Patel KJ, Volker SE, Pambuccian SE, Ondrey FG, Adams GL, Gaffney PM. Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota School of Medicine, Minneapolis, Minnesota 55455, USA. Molecular studies of squamous cell carcinoma of the head and neck (HNSCC) have demonstrated multiple genetic abnormalities such as activation of various oncogenes (Ras, Myc, epidermal growth factor receptor, and cyclin D1), tumor suppressor gene inactivation (TP53 and p16), and loss of heterozygosity at numerous chromosomal locations. Despite these observations, accurate and reliable biomarkers that predict patients at highest risk for local recurrence have yet to be defined. In an effort to identify gene expression signatures that may serve as biomarkers, we studied 41 squamous cell carcinoma tumors (25 primary and 16 locally recurrent) from various anatomical sites and 13 normal oral mucosal biopsy samples from healthy volunteers with microarray analysis using Affymetrix U133A GeneChip arrays. Differentially expressed genes were identified by calculating generalized t tests (P < 0.001) and applying a series of filtering criteria to yield a highly discriminant list of 2890 genes. Hierarchical clustering and image generation using standard software were used to visualize gene expression signatures. Several gene expression signatures were readily identifiable in the HNSCC tumors, including signatures associated with proliferation, extracellular matrix production, cytokine/chemokine expression, and immune response. Of particular interest was the association of a gene expression signature enriched for genes involved in tumor invasion and metastasis with patients experiencing locally recurrent disease. Notably, these tumors also demonstrated a marked absence of an immune response signature suggesting that modulation of tumor-specific immune responses may play a role in local treatment failure. These data provide evidence for a new gene expression-based biomarker of local treatment failure in HNSCC. PMID: 14729608 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 120: Mol Cancer. 2004 Jan 16;3:3. N-methyl-N'-nitro-N-nitrosoguanidine-induced senescence-like growth arrest in colon cancer cells is associated with loss of adenomatous polyposis coli protein, microtubule organization, and telomeric DNA. Jaiswal AS, Multani AS, Pathak S, Narayan S. UF Shands Cancer Center and Anatomy and Cell Biology, College of Medicine, Academic Research Building, Room R4-216, PO Box 100232, University of Florida, Gainesville, FL 32610, USA. ajaiswal@ufscc.ufl.edu BACKGROUND: Cellular senescence is a state in which mammalian cells enter into an irreversible growth arrest and altered biological functions. The senescence response in mammalian cells can be elicited by DNA-damaging agents. In the present study we report that the DNA-damaging agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is able to induce senescence in the HCT-116 colon cancer cell line. RESULTS: Cells treated with lower concentrations of MNNG (0-25 microM) for 50 h showed a dose-dependent increase in G2/M phase arrest and apoptosis; however, cells treated with higher concentrations of MNNG (50-100 microM) showed a senescence-like G0/G1 phase arrest which was confirmed by increased expression of beta-galactosidase, a senescence induced marker. The G2/M phase arrest and apoptosis were found to be associated with increased levels of p53 protein, but the senescence-like G0/G1 phase arrest was dissociated with p53 protein levels, since the p53 protein levels decreased in senescence-like arrested cells. We further, determined whether the decreased level of p53 was a transcriptional or a translational phenomenon. The results revealed that the decreased level of p53 protein in senescence-like arrested cells was a transcriptional phenomenon since p53 mRNA levels simultaneously decreased after treatment with higher concentrations of MNNG. We also examined the effect of MNNG treatment on other cell cycle-related proteins such as p21, p27, cyclin B1, Cdc2, c-Myc and max. The expression levels of these proteins were increased in cells treated with lower concentrations of MNNG, which supported the G2/M phase arrest. However, cells treated with higher concentrations of MNNG showed decreased levels of these proteins, and hence, may not play a role in cell cycle arrest. We then examined a possible association of the expression of APC protein and telomeric DNA signals with cellular senescence in MNNG-treated cells. We found that protein and mRNA levels of APC were drastically reduced in cells treated with higher concentrations of MNNG. The loss of APC expression might lead to chromosomal instability as well as microtubular disorganization through its dissociation with tubulin. In fact, the protein level of alpha-tubulin was also drastically decreased in senescence-like arrested cells treated with higher concentrations of MNNG. The levels of telomeric DNA also decreased in cells treated with higher concentrations of MNNG. CONCLUSIONS: These results suggest that in response to DNA alkylation damage the senescence-like arrest of HCT-116 cells was associated with decreased levels of APC protein, microtubular organization, and telomeric DNA. PMID: 14728717 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 121: Oncogene. 2004 Jan 15;23(2):350-8. E6/E7 proteins of HPV type 16 and ErbB-2 cooperate to induce neoplastic transformation of primary normal oral epithelial cells. Al Moustafa AE, Foulkes WD, Benlimame N, Wong A, Yen L, Bergeron J, Batist G, Alpert L, Alaoui-Jamali MA. Lady Davis Institute for Medical Research of the Sir Mortimer B. Davis-Jewish General Hospital, Department of Medicine, and Center for Translational Research in Cancer, Quebec, Canada. Head and neck squamous cell carcinomas (HNSCC) are characterized by a marked propensity for local invasion and spread to cervical lymph nodes, with distant metastases developing in 30-40% of cases. HPV-16 is an important risk factor for HNSCC. How HPV enhances susceptibility to HNSCC is not fully understood, but seems to involve cofactors. In this study, we examined the effect of the cooperation between HPV-16 and the tyrosine kinase receptor ErbB-2 on E-cadherin/catenin complex patterns and neoplastic transformation of human normal oral epithelial (NOE) cells. We report that overexpression of ErbB-2 or E6/E7 alone does not affect E-cadherin/catenin complex patterns nor does it induce cell transformation of NOE cells. In contrast, coexpression of E6/E7 and ErbB-2 downregulates E-cadherin and catenin expression. This is accompanied by cytoplasmic localization of E-cadherin, as well as nuclear translocation of alpha, beta, and gamma-catenins. Furthermore, we demonstrate that E6/E7 cooperate with overexpressed ErbB-2 to induce tumor formation in nude mice and to upregulate cyclin D1 and c-myc expression. Our data suggest that E6/E7 cooperate with ErbB-2 in head and neck carcinogenesis, at least in part, via the conversion of beta-catenin from a cell adhesion to a nuclear function, that is, to act as a potential transcriptional regulator. This conversion leads to the upregulation of cyclin D1, c-myc and other oncoproteins necessary for alteration of the E-cadherin/catenin complex and cell transformation of NOE cells. PMID: 14724563 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 122: Ai Zheng. 2004 Jan;23(1):99-103. [Abnormalities of molecular biology in premalignant lung lesions] [Article in Chinese] Shao SJ, Wang Y, Yang PM. Cellular and Molecular Biology Key Laboratory of Liaoning Province, Dalian Medical University, Dalian, 116027, P.R.China. shaoshujuan@sohu.com In recent twenty years, the incidence of lung cancer has increased quickly in our country. Till now, the morbidity and mortality of lung cancer have occupied the top of the cancers. Early diagnosis is the most important key to increase the five-year survival rate. This review is attempted to summarize the early hereditary events during the development of lung cancer, mainly including the mutation of p53 gene, the abnormal methylation of the promoter area of p16 gene, the loss of heterozygosity of 3p, 8p, 9p, 5q, etc. The purpose is to seek the biological markers during the development of lung cancer to provide theoretical basis for treatment of lung cancer. Publication Types: Review Review, Tutorial PMID: 14720385 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 123: Leukemia. 2004 Mar;18(3):584-8. Inactivation of the ARF-MDM-2-p53 pathway in sporadic Burkitt's lymphoma in children. Wilda M, Bruch J, Harder L, Rawer D, Reiter A, Borkhardt A, Woessmann W. Department of Pediatric Hematology and Oncology, Justus-Liebig-University, Giessen, Germany. Burkitt's lymphomas (BLs) are characterized by an activated MYC gene that provides a constitutive proliferative signal. However, activated myc can initiate ARF-dependent activation of p53 and apoptosis as well. Data derived from cell culture and animal models suggest that the inactivation of the ARF-MDM-2-p53 apoptotic signaling pathway may be a necessary secondary event for the development of BL. This has not been tested in freshly excised BL tissue. We investigated the ARF-MDM-2-p53 pathway in tumor specimen from 24 children with sporadic BL/B-ALL. Direct sequencing revealed a point mutation in the p53 gene in four BL. Overexpression of MDM-2 was evident in 10 of the BL samples analyzed by real-time quantitative PCR. Deletion of the CDKN2A locus that encodes ARF or reduced expression of ARF could not be detected in any BL by fluorescence in situ hybridization analysis or real-time quantitative PCR, respectively. Our results indicate that the ARF-MDM-2-p53 apoptotic pathway is disrupted in about 55% of the cases of childhood sporadic BL. We suggest that in addition to the inactivation of the ARF-MDM-2-p53 protective checkpoint function other antiapoptotic mutations may occur in a substantial part of children with sporadic BL. PMID: 14712292 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 124: Mutat Res. 2004 Jan 10;557(1):63-74. Non-thermal effects of power-line magnetic fields (50 Hz) on gene expression levels of pluripotent embryonic stem cells-the role of tumour suppressor p53. Czyz J, Nikolova T, Schuderer J, Kuster N, Wobus AM. In Vitro Differentiation Group, Institute of Plant Genetics and Crop Plant Research (IPK), Correnstr. 3, D-06466 Gatersleben, Germany. The diffusion of extremely low-frequency (50 Hz) electromagnetic fields (ELF-EMF) in the human environment raises the question of the induction of biological effects of EMF on mammalian cells. We used the model of mouse pluripotent embryonic stem (ES) cells, which have the capacity to develop in vitro into cells of all lineages, to analyse non-thermal effects of ELF-EMF. Wild type (wt) and p53-deficient ES cells were exposed under controlled conditions to ELF-EMF signals simulating power-line (50 Hz) magnetic field (PL-MF) exposure. Different flux densities of 0.1 mT, 1.0 mT or 2.3 mT and intermittency schemes with various ON/OFF cycles were applied for 6 h or 48 h during the first stages of cell differentiation. Transcript levels of regulatory genes, such as egr-1, p21, c-jun, c-myc, hsp70 and bcl-2, were analysed by semi-quantitative RT-PCR immediately after exposure or after a recovery time of 18 h. Intermittent PL-MF exposure to 5 min ON/30 min OFF cycles at a flux density of 2.3 mT for 6 h resulted in a significant up-regulation of c-jun, p21 and egr-1 mRNA levels in p53-deficient, but not in wild-type cells. No significant effects were observed in both cell systems by PL-MF at lower flux densities, longer exposure time or after 18 h recovery time. Our data indicate that 5 min ON/30 min OFF intermittent PL-MF exposure is capable of evoking non-thermal responses in ES cells, dependent on the cellular p53 function. The nature of the biological responses triggered by PL-MF is discussed. PMID: 14706519 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 125: Lung. 2003;181(5):245-58. Investigation of c-myc and p53 gene alterations in the tumor and surgical borderline tissues of NSCLC and effects on clinicopathologic behavior: by the FISH technique. Yakut T, Egeli U, Gebitekin C. Department of Medical Biology and Genetics, Faculty of Medicine, University of Uludag, Bursa, Turkey. tyakut@uludag.edu.tr Genetic alterations on the primary tumoral tissues and surgical borderline tissues of 51 patients with NSCLC on which radiotherapy and chemotherapy had not been performed were analyzed by using the FISH method with locus-specific probes for p53 tumor suppressor gene and c-myc oncogene and centromere-specific probes for chromosome 17 and chromosome 8 on which these genes are located. P53 deletions were detected in 7 patients (13.7%), c-myc amplification in 4 patients (7.8%), monosomy 17 in 2 patients (3.9%) and trisomy 8 in 3 patients (5.8%), and a high level of polyploidy in tumoral tissues of 6 patients (11.7%). P53 deletion and c-myc amplification were found at surgical borderlines of 2 patients and 1 patient, respectively. Although both p53 deletion and c-myc amplification have low frequency at surgical border tissues, not only their detection is important for the follow-up of recurrency and metastasis, but it is also important for genetical and pathological staging. The results of this study show that c-myc amplification in NSCLC is related to the shortening of survival (p < 0.01). C-myc amplification and p53 deletion are also effective for the occurrence of metastasis (p < 0.05) and the effect of c-myc amplification in this matter is much higher than p53 deletion. The gain or loss of copy number of chromosome 8 and monosomy 17 show parallel effects with c-myc amplification and p53 deletion, respectively, on the clinicopathological behavior of tumors. PMID: 14705768 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 126: Acta Pharmacol Sin. 2004 Jan;25(1):47-53. Effects of 15-deoxy-delta12,14-prostaglandin J2 on cell proliferation and apoptosis in ECV304 endothelial cells. Dong YG, Chen DD, He JG, Guan YY. Department of Cardiology, First Affiliated Hospital, Zhongshan University, Guangzhou 510080, China. yugangdong@gzsums.edu.cn AIM: To investigate the effects of 15-deoxy-delta12,14-prostaglandin J2 (15d-PGJ2) on cell proliferation and apoptosis in ECV304 endothelial cells and related molecular mechanism. METHODS: MTT, Hoechst33258, TUNEL, Flow cytometry, DNA ladder, RT-PCR, Western blot, and electrophoretic mobility shift assay (EMSA) analysis were employed. RESULTS: The 15d-PGJ2 induced apoptosis in ECV304 endothelial cells in a dose-dependent manner (the percentage of apoptosis was enhanced from 10.0 %+/-1.3 % to 32.8 %+/-1.6 %), which was accompanied by inhibition of NF-?B and AP-1 DNA binding activity, down-regulation of c-myc, upregulation of Gadd45 and p53, and activation of p38 kinase. However, the expression of p21 was found no significant change. CONCLUSION: peroxisome proliferator-activated receptor gamma ligand, 15d-PGJ2, can inhibit proliferation and induce apoptosis in ECV304 endothelial cells through different mechanisms. PMID: 14704122 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 127: Osteoarthritis Cartilage. 2004 Jan;12(1):1-16. Cell death in cartilage. Kuhn K, D'Lima DD, Hashimoto S, Lotz M. Division of Arthritis Research, Department of Molecular and Experimental Medicine, The Scripps Research Institute, CA, La Jolla 92037, USA. Publication Types: Review Review, Tutorial PMID: 14697678 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 128: Cancer. 2003 Dec 15;98(12):2554-9. Correlation of Bcl-2 and p53 expression in primary breast tumors and corresponding metastatic lymph nodes. Arun B, Kilic G, Yen C, Foster B, Yardley D, Gaynor R, Ashfaq R. Division of Hematology and Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 77030, USA. barun@mdanderson.org BACKGROUND: The p53 tumor suppressor gene product participated in G1 cell cycle arrest or cell death. Loss of function was associated with poor outcome in patients with breast carcinoma. bcl-2 prevented apoptosis induced by c-myc or growth factor deprivation. High bcl-2 expression in breast tumor tissue specimens appears to be associated with favorable prognostic factors. However, Bcl-2 and p53 expression in primary tumor tissue specimens versus metastatic lymph node specimens in breast carcinoma has not been studied. The current study compared Bcl-2 and p53 expression in primary breast carcinoma tissue specimens with Bcl-2 and p53 expression in axillary lymph node specimens. METHODS: Primary breast tumor and corresponding axillary metastatic lymph node tissue specimens were obtained from 60 patients with breast carcinoma. They were evaluated for the presence of Bcl-2 and p53 expression by immunohistochemistry using standard methods. RESULTS: Bcl-2 expression in primary tumor tissue specimens (53%) was correlated with Bcl-2 expression in metastatic lymph node specimens (50 %; Pearson correlation = 0.656). p53 expression in primary tumor specimens (72%) was correlated with p53 expression in metastatic lymph node specimens (60 %; Pearson correlation = 0.800). A significant inverse correlation also was found between p53 and Bcl-2 expression in primary breast tumor tissue specimens (Pearson correlation = -0.310). CONCLUSIONS: The current study suggested that Bcl-2 and p53 expression in axillary metastatic lymph node specimens is correlated with Bcl-2 and p53 expression in the primary tumor tissue specimens. The prognostic and predictive value of Bcl-2 and p53 expression in axillary lymph node metastasis in patients with breast carcinoma needs to be further evaluated in larger trials with longer follow-up. Copyright 2003 American Cancer Society. PMID: 14669273 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 129: Mol Cell Proteomics. 2004 Feb;3(2):176-82. Epub 2003 Dec 9. Two-dimensional Blue native/SDS gel electrophoresis of multi-protein complexes from whole cellular lysates: a proteomics approach. Camacho-Carvajal MM, Wollscheid B, Aebersold R, Steimle V, Schamel WW. Max Planck-Institute of Immunobiology, Stubeweg 51, 79108 Freiburg, Germany. Identification and characterization of multi-protein complexes is an important step toward an integrative view of protein-protein interaction networks that determine protein function and cell behavior. The limiting factor for identifying protein complexes is the method for their separation. Blue native PAGE (BN-PAGE) permits a high-resolution separation of multi-protein complexes under native conditions. To date, BN-PAGE has only been applicable to purified material. Here, we show that dialysis permits the analysis of multi-protein complexes of whole cellular lysates by BN-PAGE. We visualized different multi-protein complexes by immunoblotting including forms of the eukaryotic proteasome. Complex dynamics after gamma interferon stimulation of cells was studied, and an antibody shift assay was used to detect protein-protein interactions in BN-PAGE. Furthermore, we identified defined protein complexes of various proteins including the tumor suppressor p53 and c-Myc. Finally, we identified multi-protein complexes via mass spectrometry, showing that the method has a wide potential for functional proteomics. PMID: 14665681 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 130: Oncogene. 2003 Dec 8;22(56):9007-21. Myc pathways provoking cell suicide and cancer. Nilsson JA, Cleveland JL. Department of Biochemistry, St Jude Children's Research Hospital, 332 N Lauderdale, Memphis, TN 38105, USA. A paradox for the cancer biology field has been the revelation that oncogenes, once thought to simply provide advantages to a cancer cell, actually put it at dire risk of cell suicide. Myc is the quintessential oncogene in this respect, as in normal cells it is required for cell cycle traverse, whereas in cancers it is overexpressed and functions as the angiogenic switch. Nonetheless, Myc overexpression kills normal cells dead in their tracks. Here we review Myc-induced pathways that contribute to the apoptotic response. Molecular analysis of Myc-induced tumors has established that some of these apoptotic pathways are essential checkpoints that guard the cell from cancer, as they are selectively bypassed during tumorigenesis. The precise mechanism(s) by which Myc targets these pathways are largely unresolved, but we propose that they involve crosstalk and feedback regulatory loops between arbiters of cell death. Publication Types: Review PMID: 14663479 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 131: J Clin Invest. 2003 Dec;112(11):1724-31. Myc confers androgen-independent prostate cancer cell growth. Bernard D, Pourtier-Manzanedo A, Gil J, Beach DH. Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, United Kindom. Prostate cancer is one of the most diagnosed and mortal cancers in western countries. A major clinical problem is the development of androgen-independent prostate cancer (AIPC) during antihormonal treatment. The molecular mechanisms underlying the change from androgen dependence to independence of these tumors are poorly understood and represent a challenge to develop new therapies. Based on genetic data showing amplification of the c-myc gene in AIPC, we studied the ability of c-myc to confer AIPC cell growth. Human androgen-dependent prostate cancer cells overexpressing c-myc grew independently of androgens and presented tumorigenic properties in androgen-depleted conditions. Analysis of signalling pathways by pharmacological inhibitors of the androgen receptor (AR) or by RNA interference directed against AR or c-myc showed that c-myc acted downstream of AR through multiple growth effectors. Thus c-myc is required for androgen-dependent growth and following ectopic expression can induce androgen-independent growth. Moreover, RNA interference directed against c-myc showed that growth of human AIPC cells, AR-positive or -negative, required c-myc expression. Furthermore, we showed that c-myc-overexpressing cells retain a functional p53 pathway and thus respond to etoposide. PMID: 14660748 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 132: Invest Ophthalmol Vis Sci. 2003 Dec;44(12):5293-300. The toxic and stress responses of cultured human retinal pigment epithelium (ARPE19) and human glial cells (SVG) in the presence of triamcinolone. Yeung CK, Chan KP, Chiang SW, Pang CP, Lam DS. Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, 147K Argyle Street, Kowloon, People's Republic of China. ckcyeung@cuhk.edu.hk PURPOSE: To compare the cytotoxic effect of TA on human retinal pigment epithelium (ARPE19) and human glial (SVG) cells over a range of concentrations and durations of exposure. METHODS: TA (0.01-1 mg/mL) or vehicle (benzyl alcohol, 0.025%) was added to the ARPE19 and SVG cultures on day 0 and then subsequently for 1, 3, or 5 days. The amount of cell proliferations with or without TA treatment was performed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. All samples were read in triplicate (n = 4 in all cases). c-Fos, c-jun, caspase-3, c-myc, and p53 expression was determined after TA treatments after 0, 10, 20, 30, 40, 50, 60, and 90 minutes. All results were analyzed with ANOVA. RESULTS: TA (0.01-1 mg/mL) caused a significant reduction in ARPE19 cells that had been exposed to it for more than 1 day. Significant reductions in the number of SVG cells were observed as early as day 1 at 0.1 and 1 mg/mL TA. In general, the level of remaining SVG cells was less than that of the APRE19 cells over the 5 days. SVG cells appeared more susceptible to TA. Caspase-3 was elevated in both ARPE19 and SVG cells after TA treatment. c-Fos and c-jun expression was also increased in ARPE19 cells but not in SVG. The vehicle of TA had no effect, and there was no change in p53 or c-myc expression. CONCLUSIONS: TA was cytotoxic to both SVG and ARPE19 cells, with higher efficacy on SVG. TA caused the activation of the caspase-3 pathway more readily than the cell-protective c-fos and c-jun pathways in SVG cells, making those cells more vulnerable than the ARPE19 cells. The results suggest that TA toxicity in one cell type may not reliably indicate its toxicity in other cells. Different cells within the retina may react to TA differently, or TA may cause changes in the gene expressions differentially with different concentrations of the same stimulus. PMID: 14638729 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 133: J Cell Biochem. 2003 Dec 15;90(6):1242-9. GADD34 induces p53 phosphorylation and p21/WAF1 transcription. Yagi A, Hasegawa Y, Xiao H, Haneda M, Kojima E, Nishikimi A, Hasegawa T, Shimokata K, Isobe K. Department of Basic Gerontology, National Institute for Longevity Sciences, Morioka-cho, Obu, Aichi 474-8522, Japan. Recently, others and we have shown that one of the functions of GADD34 is a recovery from a shutoff of protein synthesis induced by endoplasmic reticulum stress. GADD34 has been shown to induce growth arrest and apoptosis. Main protein of apoptosis is p53, especially phosphorylation of p53. And one of the main proteins of growth arrest is p21/WAF1. Here we analyzed the effects of GADD34 on p53 phosphorylation and p21/WAF1 transcription. Transfected Myc-tagged p53 was dose-dependently phosphorylated at Ser15 by increasing the amount of GADD34. Transfection of GADD34 also induced the endogenous phosphorylation of p53 and enhanced p21 protein expression. Transfection of GADD34 induced p21/WAF1 promoter activity. This activity was dependent on p53, because GADD34 transfection to p53-deficient cells produced only a slight increase of p21/WAF1 promoter activity. The p21/WAF1 promoter activity was greatly enhanced by the transfection of p53. Both GADD34 and p53 transfection induced much higher p21/WAF1 promoter activity. The promoter activity of p21/WAF1 was very low in GADD34 deficient MEF. The transfection of GADD34 increased the p21/WAF1 promoter activity in GADD34 deficient MEF. Copyright 2003 Wiley-Liss, Inc. PMID: 14635196 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 134: Cancer Res. 2003 Nov 15;63(22):8037-50. Signaling pathways of apoptosis activated by aromatase inhibitors and antiestrogens. Thiantanawat A, Long BJ, Brodie AM. Department of Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, Health Science Facility, Room 580G, 685 West Baltimore Street, Baltimore, MD 21201, USA. Aromatase inhibitors have recently been reported to be more effective than the antiestrogen tamoxifen (Tam) in treating breast cancer. Here, we studied the mechanisms and signaling pathways of cell growth, cell cycle progression, and apoptosis induced by three aromatase inhibitors: letrozole (Let), anastrozole, and 4-hydroxyandrostenedione in comparison with estrogen withdrawal (E2W) and antiestrogens Tam and faslodex. Estrogen-dependent human breast cancer cells stably transfected with aromatase (MCF-7Ca) were used. All treatments induced growth suppression and cell cycle arrest at the G(0)-G(1) phase that was associated with up-regulation of p53 and p21 protein and mRNA levels and down-regulation of cyclin D1 and c-myc mRNA. The apoptotic index was increased 4-7 fold, Bcl-2 protein expression decreased, Bax increased, and caspase-9, caspase-6, and caspase-7 were activated but not caspase-3 and caspase-8. Let and E2W caused regression of tumors of MCF-7Ca cells grown in nude mice and increased the number of cells undergoing apoptosis. In contrast, Tam and faslodex did not induce tumor regression and a lower number of apoptotic cells was detected. Cleavage of poly(ADP-ribose) polymerase was detected. Treatment with Let, Tam, or E2W resulted in a dose- and time-dependent increase in active caspase-7 and up-regulation of p53 and p21 protein. Although the mechanisms involved appeared to be similar for antiestrogens and aromatase inhibitors, the most significant effects occurred with Let, which were significantly greater than with E2W and consistent with marked effects of Let on tumor and cell growth. PMID: 14633737 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 135: J Biol Chem. 2004 Feb 6;279(6):4305-12. Epub 2003 Nov 19. c-Myc sensitization to oxygen deprivation-induced cell death is dependent on Bax/Bak, but is independent of p53 and hypoxia-inducible factor-1. Brunelle JK, Santore MT, Budinger GR, Tang Y, Barrett TA, Zong WX, Kandel E, Keith B, Simon MC, Thompson CB, Hay N, Chandel NS. Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611-3010, USA. Deregulated expression of c-Myc can sensitize cells to a variety of death stimuli, including loss of growth factors and oxygen. In this study, we examined whether rodent fibroblasts that conditionally express c-Myc undergo a similar mechanism of cell death in response to serum or oxygen deprivation. Our results demonstrate that murine embryonic fibroblasts from bax-/-bak-/- mice that conditionally express c-Myc did not die in response to either oxygen or serum deprivation. Fibroblasts from p53-/- mice that conditionally express c-Myc died in response to oxygen (but not serum) deprivation. The inability of p53 to regulate oxygen deprivation-induced cell death was due to the lack of induction of p53 target genes Puma, Noxa, and Pten. In contrast, serum deprivation transcriptionally induced Puma and Pten in cells that conditionally express c-Myc. The failure of p53 to regulate oxygen deprivation-induced cell death led us to hypothesize whether hypoxia-inducible factor (HIF) might be a critical regulator of cell death during oxygen deprivation. Fibroblasts from HIF-1beta-/- cells that conditionally express c-Myc were not able to transcriptionally activate HIF during oxygen deprivation. These cells died in response to oxygen deprivation. Thus, oxygen deprivation-induced cell death in fibroblasts with deregulated expression of c-Myc is independent of p53 or HIF-1 status, but is dependent on the Bcl-2 family member Bax or Bak to initiate mitochondrial dependent cell death. PMID: 14627695 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 136: Int J Oncol. 2003 Dec;23(6):1529-35. In situ detection of telomeres by fluorescence in situ hybridization and telomerase activity in glioblastoma multiforme: correlation with p53 status, EGFR, c-myc, MIB1, and Topoisomerase IIalpha protein expression. Miracco C, De Santi MM, Luzi P, Lalinga AV, Laurini L, De Nisi MC, Angeloni G, Brogi M, Cardone C, Carducci A, Arcuri F, Tosi P, Rubino G, Pirtoli L. Dipartimento di Patologia Umana e Oncologia, Sezione di Anatomia Patologica, Policlinico Le Scotte, I-53100 Siena, Italy. miracco@unisi.it Aberrations of genes/proteins regulating cell cycle and growth, increased proliferation and telomerase activity (TA) are documentable in glioblastoma multiforme. TA is more frequently detectable in secondary glioblastoma, which is also characterized by p53 mutation/overexpression. Discordant telomere (Te) length values have been reported in glioblastomas with and without TA. In 31 glioblastomas, in which pre-existing astrocytoma was not documented, we compared cases with and without TA for the expression of p53, EGFR, c-Myc, MIB-1 and Topoisomerase IIalpha; p53 mutations were also investigated by SSCP-PCR. Correlations were made with Te parameters [TePs: number (TeNo), length and area] as evaluated by image analysis in interphase nuclei of fluorescence in situ hybridization (FISH)-processed sections. We found no differences in the expression of the proteins evaluated and in TePs, except Te/nuclear area %, which was significantly lower in TA+ cases (p=0.02). TePs were, instead, inversely correlated with TA (p=0.0001). TA was positively correlated with MIB1 staining index in the TA+ cases (p=0.033), which also showed a positive correlation between TeNo and EGFR expression (p=0.042), and a trend towards a negative correlation between TeNo and p53 expression (p=0.05). Tumors overexpressing EGFR had a significantly shorter lifetime (p=0.0001). TeNo seems to be inversely correlated to tumor proliferation and lifetime in glioblastoma multiforme. PMID: 14612923 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 137: Cancer Res. 2003 Nov 1;63(21):7147-57. Prolonged culture of telomerase-immortalized human fibroblasts leads to a premalignant phenotype. Milyavsky M, Shats I, Erez N, Tang X, Senderovich S, Meerson A, Tabach Y, Goldfinger N, Ginsberg D, Harris CC, Rotter V. Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel. Telomere shortening in primary human fibroblasts results in replicative senescence, which can be overcome by telomerase (hTERT) overexpression. However, because immortalization is one of the hallmarks of malignant transformation, careful analysis of hTERT-immortalized cells is of crucial importance for understanding both processes. To this end, we infected WI-38 fibroblasts with a retrovirus carrying the hTERT cDNA and analyzed their proliferative behavior during 600 days [ approximately 500 population doublings (PDLs)] of continuous culture. Growth of three independent mass cultures was uniform for approximately 150 PDLs after telomerase infection, followed by a progressive acceleration of growth in two of three cultures. Expression of p16(INK4A) was significantly elevated in the immortalized cells but gradually disappeared during the accelerated growth phase. This alteration correlated with loss of the contact inhibition response and conferred the cells with sensitivity to H-Ras-induced transformation. In contrast, the p53- and pRb-mediated checkpoints such as the DNA damage response, chromosomal stability and entry into quiescence remained intact, irrespective of INK4A locus expression. Importantly, detailed examination of one of the WI-38/hTERT cultures during the accelerated growth phase revealed overexpression of the c-myc and Bmi-1 oncogenes, as well as loss of p14(ARF) expression. Collectively, our results indicate that although hTERT-immortalized cells behave similarly to primary cells during the first 150 PDLs, long-term growth in culture may favor the appearance of clones carrying potentially malignant alterations. PMID: 14612508 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 138: Cancer Cell. 2003 Oct;4(4):321-8. Puma is an essential mediator of p53-dependent and -independent apoptotic pathways. Jeffers JR, Parganas E, Lee Y, Yang C, Wang J, Brennan J, MacLean KH, Han J, Chittenden T, Ihle JN, McKinnon PJ, Cleveland JL, Zambetti GP. St. Jude Children's Research Hospital, 332 N. Lauderdale, Memphis, TN 38105, USA. Puma encodes a BH3-only protein that is induced by the p53 tumor suppressor and other apoptotic stimuli. To assess its physiological role in apoptosis, we generated Puma knockout mice by gene targeting. Here we report that Puma is essential for hematopoietic cell death triggered by ionizing radiation (IR), deregulated c-Myc expression, and cytokine withdrawal. Puma is also required for IR-induced death throughout the developing nervous system and accounts for nearly all of the apoptotic activity attributed to p53 under these conditions. These findings establish Puma as a principal mediator of cell death in response to diverse apoptotic signals, implicating Puma as a likely tumor suppressor. PMID: 14585359 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 139: Cancer Cell. 2003 Oct;4(4):301-10. Tumor suppressor p16INK4a determines sensitivity of human cells to transformation by cooperating cellular oncogenes. Drayton S, Rowe J, Jones R, Vatcheva R, Cuthbert-Heavens D, Marshall J, Fried M, Peters G. Molecular Oncology Laboratory, Cancer Research UK London Research Institute, Lincolns Inn Fields, London WC2A 3PX, United Kingdom. The Ink4a/Arf locus encodes two distinct proteins, both of which may contribute to senescence and tumor suppression. We find that human diploid fibroblasts (HDFs) that are specifically deficient for p16INK4a achieve anchorage independence when transduced with retroviruses encoding telomerase (hTERT) and either Ras or Myc. Significantly, Ras and Myc together enable the cells to form tumors in nude mice but at a frequency that suggests additional genetic changes. All five tumors analyzed expressed high levels of Ras and retained functional p53, although two showed downregulation of Arf. Cytogenetic analyses identified clonal chromosomal alterations that may have contributed to tumorigenesis, but the tumor cells were essentially diploid. PMID: 14585357 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 140: Essays Biochem. 2003;39:89-104. Oncogenes as regulators of apoptosis. Labazi M, Phillips AC. Medical College of Georgia, Institute of Molecular Medicine and Genetics, CB2803, 1120 15th Street, Augusta, GA 30912, U.S.A. Although cancer is a disease that will afflict one out of three people in the Western world, when considered at a cellular level, it is a rare clonal event. Long-lived organisms, such as humans, have evolved strategies to restrict the development of potentially malignant cells, and one such mechanism is the coupling of proliferative and apoptotic pathways. Multiple oncogenes have the ability to trigger apoptosis when expressed in an inappropriate fashion, and this is thought to restrict tumour formation by eliminating potentially malignant cells that have acquired a mutation stimulating proliferation. Hence for a tumour to arise, in addition to mutations that drive proliferation, mutations that prevent apoptosis are also a prerequisite. Publication Types: Review Review, Tutorial PMID: 14585076 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 141: Yi Chuan Xue Bao. 2003 Sep;30(9):797-803. Expressions of human p53 and c-myc gene homologues during caryopsis development in maize. Qi CY, Ning SB, Wang N, Li LJ, Song YC. Key Laboratory of MOE for Plant Developmental Biology, Wuhan University, Wuhan 430072, China. Tumor suppressor gene p53 and proto-oncogene c-myc have been proved to be highly conserved and participate in many PCD processes in animals. In maize, proteins and RNAs related to p53 and c-myc have already been reported and the sequences homologous to these two genes have also been localized onto maize chromosomes by FISH. In this study, using immunohistochemistry we investigated the expression patterns of maize genes homologous to human p53 and c-myc during caryopsis development stages in maize. In a giving stage after pollination, p53 homologue showed high levels in the antipodal cells, integument, immature endosperm, ovary wall, tracheary elements, and aleurone layer, while c-myc homologue showed low levels in these tissues, only before pollination showed high expression in polar nucleus. The results of TUNEL assay demonstrated that TUNEL positive signals were detected where p53 homologue showed high expression levels. In animal cells, p53 shows reverse function with that of c-myc, so does it in maize basically. These results demonstrated that p53 and c-myc homologues might play some important roles in PCD during caryopsis development in maize. There may be conserved mechanisms for PCD in animals and in high plants. PMID: 14577369 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 142: J Biol Chem. 2003 Dec 19;278(51):50915-22. Epub 2003 Oct 13. Increased expression of Bcl-xL and c-Myc is associated with transformation by Abelson murine leukemia virus. Noronha EJ, Sterling KH, Calame KL. Department of Microbiology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA. Transformation mediated by the v-Abl oncoprotein, a tyrosine kinase encoded by the Abelson murine leukemia virus, is a multi-step process requiring genetic alterations in addition to expression of v-Abl. Loss of p53 or p19ARF was previously shown to be required for Abelson murine leukemia virus transformation of primary mouse embryonic fibroblasts (MEFs). By comparing gene expression patterns in primary p53-/- MEFs acutely infected with the v-Abl retrovirus, v-Abl-transformed MEF clones, and v-Abl-transformed MEF clones treated with Abl kinase inhibitor STI 571, we have identified additional genetic alterations associated with v-Abl transformation. Bcl-xL mRNA was elevated in three of five v-Abl-transformed MEF clones. In addition, elevated expression of c-Myc mRNA, caused either by c-myc gene amplification or by enhanced signaling via STAT3, was observed in five v-Abl-transformed MEF clones. The data suggest that increases in cell survival associated with Bcl-xL and increases in cell growth associated with c-Myc facilitate the transformation process dependent on constitutive mitogenic signaling by v-Abl. PMID: 14559912 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 143: Mol Cancer Ther. 2003 Sep;2(9):893-900. Amifostine impairs p53-mediated apoptosis of human myeloid leukemia cells. Acosta JC, Richard C, Delgado MD, Horita M, Rizzo MG, Fernandez-Luna JL, Leon J. Grupo de Biologia Molecular del Cancer, Departamento de Biologia Molecular, Unidad de Biomedicina-CSIC, Universidad de Cantabria, Santander, Spain. Amifostine is used as a cytoprotective agent in cancer treatments. Amifostine protects from apoptosis in some models and has been used as hematopoiesis stimulator in myeloid malignancies. As the apoptosis induced by many antitumoral agents is mediated by p53, we studied the effect of amifostine on p53-mediated apoptosis. We used human myeloid leukemia K562 and NB4 cells expressing the temperature-conditional p53-Val(135) mutant. Both cell lines undergo apoptosis at 32 degrees C due to the presence of p53 in wild-type conformation. We found that amifostine dramatically reduced apoptosis by p53 in both cell lines, as assessed by cell morphology, annexin V binding, fraction of sub-G(1) cells, and DNA laddering. To explore the mechanism responsible for this apoptosis protection, we tested the effect of amifostine on p53 transcriptional activity. We found that amifostine reduced p53-mediated transactivation of target promoters in NB4 and K562. Macroarray analysis confirmed that several p53 target genes as p21(Waf1), mdm2, gadd45, pig8, and pig3 were down-regulated at the mRNA level by amifostine in NB4 and K562. Also, c-myc was up-regulated by amifostine in K562 in the presence of p53, consistently with the impairment of p53-mediated apoptosis exerted by c-Myc in these cells. We conclude that amifostine impairs p53-dependent apoptosis of myeloid leukemia cells by reducing the activation of apoptosis-related genes. Our results open the possibility that amifostine could reduce the effectiveness of antitumoral treatments when it is dependent on active p53. PMID: 14555708 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 144: Clin Cancer Res. 2003 Oct 1;9(12):4595-605. Targeted liposomal c-myc antisense oligodeoxynucleotides induce apoptosis and inhibit tumor growth and metastases in human melanoma models. Pastorino F, Brignole C, Marimpietri D, Pagnan G, Morando A, Ribatti D, Semple SC, Gambini C, Allen TM, Ponzoni M. Differentiation Therapy Unit, Laboratory of Oncology, G. Gaslini Children's Hospital, 16148 Genoa, Italy. PURPOSE: Melanoma is a highly malignant and increasingly common tumor. Because the cure rate of metastatic melanoma by conventional treatment is very low, new therapeutic approaches are needed. We previously reported that coated cationic liposomes (CCL) targeted with a monoclonal antibody against the disialoganglioside (GD(2)) and containing c-myb antisense oligodeoxynucleotides (asODNs) resulted in a selective inhibition of the proliferation of GD(2)-positive neuroblastoma cells in vitro. EXPERIMENTAL DESIGN: Here, we tested the in vivo antitumor effects of this novel antisense liposomal formulation by targeting the c-myc oncogene on melanoma, a neuroectodermal tumor sharing with neuroblastoma the expression of GD(2). RESULTS: Our methods produced GD(2)-targeted liposomes that stably entrapped 90% of added c-myc asODNs. These liposomes showed a selective binding for GD(2)-positive melanoma cells in vitro. Melanoma cell proliferation was inhibited to a greater extent by GD(2)-targeted liposomes containing c-myc asODNs (aGD(2)-CCL-myc-as) than by nontargeted liposomes or free asODNs. The pharmacokinetic results obtained after i.v. injection of [(3)H]-myc-asODNs, free or encapsulated in nontargeted CCLs or GD(2)-targeted CCLs, showed that free c-myc-asODNs were rapidly cleared, with less than 10% of the injected dose remaining in blood at 30 min after injection. c-myc-asODNs encapsulated within either CCL or aGD(2)-CCL demonstrated a more favorable profile in blood, with about 20% of the injected dose of each preparation remaining in vivo at 24 h after injection. In an in vivo melanoma experimental metastatic model, aGD(2)-CCL-myc-as, at a total dose of only 10 mg of asODN per kilogram, significantly inhibited the development of microscopic metastases in the lung compared with animals treated with myc-asODNs, free or entrapped in nontargeted liposomes, or aGD(2)-CCL encapsulating scrambled asODNs (P < 0.01). Moreover, mice bearing established s.c. human melanoma xenografts treated with aGD(2)-CCL-myc-as exhibited significantly reduced tumor growth and increased survival (P < 0.01 versus control mice). The mechanism for the antitumor effects appears to be down-regulation of the expression of the c-myc protein and interruption of c-myc-mediated signaling: induction of p53 and inhibition of Bcl-2 proteins, leading to extensive tumor cell apoptosis. CONCLUSION: These results suggest that inhibition of c-myc proto-oncogene by GD(2)-targeted antisense therapy could provide an effective approach for the treatment of melanoma in an adjuvant setting. PMID: 14555535 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 145: Int J Radiat Biol. 2003 Aug;79(8):589-600. Decreased c-Myc expression and its involvement in X-ray-induced apoptotic cell death of human T-cell leukaemia cell line MOLT-4. Enomoto A, Suzuki N, Kang Y, Hirano K, Matsumoto Y, Zhu J, Morita A, Hosoi Y, Sakai K, Koyama H. Department of Radiation Oncology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. PURPOSE: To investigate the possible involvement of c-Myc and ceramide-c-Jun N-terminal kinase (JNK) pathway in X-ray-induced apoptotic cell death of MOLT-4 cells. MATERIALS AND METHODS: The expressions of c-Myc protein and c-myc mRNA after X-irradiation were analysed by Western blotting and RT-PCR between radiosensitive MOLT-4 and radioresistant variant Rh-1a cells with less JNK activation than the parental cells. Apoptotic cell death was determined by a dye exclusion test, the appearance of chromatin condensation and DNA fragmentation. The effect of a JNK activator anisomycin or c-Myc inhibitor peptides (Int-H1-S6A, F8A) on the amount of c-Myc protein and on the induction of apoptosis was investigated, respectively. RESULTS: In X-irradiated MOLT-4 cells, amounts of both c-myc mRNA and c-Myc protein rapidly decreased, which was followed by apoptotic cell death, while little change or limited reduction of c-Myc protein was observed in X-irradiated Rh-1a cells with accompanying higher cell viability. Exposure of MOLT-4 and Rh-1a cells to c-Myc inhibitor peptides similarly induced apoptotic cell death with decreases of c-Myc protein. Anisomycin rapidly induced JNK activation and a subsequent decrease of c-Myc protein, causing cell death in MOLT-4 cells. On the other hand, Rh-1a cells were more resistant to anisomycin than parental MOLT-4 cells, showing less JNK activation and a delayed decrease of c-Myc protein. CONCLUSION: A decrease of c-Myc protein was considered important in X-ray-induced apoptotic cell death of MOLT-4 cells; activation of the JNK pathway caused reduction in the amounts of c-myc mRNA and c-Myc protein, and finally induced apoptotic cell death. PMID: 14555342 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 146: Wei Sheng Yan Jiu. 2003 Jul;32(4):304-7. [Study of 8-OH-dG and its correlation with several cancer related gene in lung cancer tissues] [Article in Chinese] Lu J, Shi L, Wu Z, Liao Y, Zhou C, Li Y, Bin X, Zeng B, Chen J. Institute for Chemical Carcinogenesis, Guangzhou Medical College, Guangzhou 510182, China. To investigate the relationship among 8-OH-dG and the development of human lung cancer and cancer related genes, an 8-OH-dG-specific monoclonal antibody and biotin-streptavidin immuno-staining were used to detect the 8-OH-dG in 150 cases of human lung cancer tissues, 120 adjacent lung tissues without cancer cells, 40 benign lung lesions and 40 normal lung tissues. The expressions of P53, C-MYC, K-RAS, BCL-2 and hTERT(human telomerase reverse transcriptase) were determined by immunohistochemistry and the relationship among the 8-OH-dG and these genes was analyzed. The 8-OH-dG were positive in 139 of 150 (92.7%) lung cancer specimens, and the percentage of adduct labeling cell in lung cancer specimens was (24.00 +/- 25.11)% (mean +/- SE). 21 of 120 (17.5%) adjacent lung tissues were adduct positive, and the percentage of adduct labeling cell was 2.42 +/- 5.98%. 4 of 40 (10.0%) benign lung lesions were adduct positive, and the percentage of adduct labeling cell was 0.80 +/- 1.30%, whereas 2 of 40 (5.0%) normal lung tissues were weak positive with 8-oh-dG, and the percentage of adduct labeling cell in this group was (0.34 +/- 1.01)%. The level of 8-OH-dG in lung cancer tissues was significantly higher than that of adjacent lung tissues, benign lung lesions and normal lungs (P < 0.01). The lung cancer patients were stratified by sex, age, cell types and smoking history, but these characteristics were not correlated with the level of 8-OH-dG. In the investigation of the relationship between the 8-OH-dG and five cancer related genes, higher 8-OH-dG levels were observed in lung cancer patients with over-expression of K-RAS and BCL-2 than those of negative expressed patients (P-value were 0.035 and 0.034 respectively), whereas the expression of P53, C-MYC and hTERT were not correlated with level of 8-OH-dG. 8-OH-dG was an important biomarker that may reflect the oxidative DNA damages of cells, and 8-OH-dG may affect K-RAS and BCL-2 genes in the carcinogenesis of lung cancer. PMID: 14535088 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 147: Int J Oncol. 2003 Nov;23(5):1451-9. Telomerase in relation to expression of p53, c-Myc and estrogen receptor in ovarian tumours. Wisman GB, Hollema H, Helder MN, Knol AJ, Van der Meer GT, Krans M, De Jong S, De Vries EG, Van der Zee AG. Department of Gynaecological Oncology, University Hospital Groningen, 9700 RB Groningen, The Netherlands. g.b.a.wisman@og.azg.nl Telomerase activity and its subunits (hTERC, hTERT mRNA) were evaluated in ovarian tumours in relation to the expression of p53, c-Myc and estrogen receptor (ER). Furthermore, relations between telomerase activity, hTERC and hTERT with known clinicopathologic prognostic factors and survival in patients with malignant tumours was investigated. Telomerase activity was determined with TRAP, hTERC and hTERT with RT-PCR, while p53, c-Myc and ER expression with immunohistochemistry. Telomerase activity and hTERT mRNA were more frequently observed in malignant ovarian tumours compared to borderline and benign tumours, whereas hTERC was present in all tumour types. p53 and c-Myc were more frequently detected in malignant compared to borderline and benign tumours. Telomerase activity was positively related to hTERT mRNA, p53 and c-Myc expression, but not to hTERC and ER expression. In malignant tumours, hTERC levels were related to tumour stage, while telomerase activity and hTERT mRNA expression were not related to any clinicopathologic feature. Tumour stage, differentiation grade, residual tumour after first laparotomy and presence of ascites were related to (progression free) survival, whereas telomerase activity or its subunits were not. In conclusion, these data suggest that p53 expression (e.g. p53 mutation) as well as c-Myc expression may have a role in regulation of telomerase activity in ovarian tumours. PMID: 14532990 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 148: J Cell Biochem. 2003 Oct 15;90(3):619-26. Overexpression of regucalcin modulates tumor-related gene expression in cloned rat hepatoma H4-II-E cells. Tsurusaki Y, Yamaguchi M. Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan. Regucalcin is a regulatory protein in intracellular signaling pathway which is related to various protein kinases and protein phosphatases in many cells. The effect of regucalcin on the expression of tumor-related genes was investigated in the cloned rat hepatoma H4-II-E cells and the hepatoma cells (transfectants) overexpressing regucalcin. Hepatoma cells were cultured for 24-72 h in the presence of fetal bovine serum (FBS; 10%). The proliferation of hepatoma cells was significantly suppressed at 24-72 h of culture in regucalcin transfectants as compared with that of wild-type or mock-type cells. Western blot analysis showed that regucalcin was markedly expressed in transfectants. The expression of c-myc, c-fos, c-jun, Ha-ras, and p53 mRNAs was determined using reverse transcription-polymerase chain reaction (RT-PCR). Of these genes, the expression of c-myc or Ha-ras mRNAs was significantly suppressed in regucalcin transfectants. The suppression of c-myc mRNA expression in transfectants was confirmed by using Northern blot analysis; significant suppression was seen at 24, 48, or 72 h of culture in the presence of 10% FBS. Culture with 10% FBS significantly enhanced c-myc mRNA expression in the hepatoma cells (wild-type) as compared with that of 1% FBS. The enhancement was significantly abolished in the transfectants. Meanwhile, the expression of p53 mRNA in the hepatoma cells was significantly enhanced in regucalcin-overexpressing hepatoma cells. This study demonstrates that the expression of oncogene c-myc and Ha-ras mRNA in hepatoma cells overexpressing regucalcin is suppressed, and that the tumor suppression gene p53 is enhanced in the transfectants. Copyright 2003 Wiley-Liss, Inc. PMID: 14523995 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 149: Cancer Res. 2003 Sep 15;63(18):5703-6. Tumor promotion by Mdm2 splice variants unable to bind p53. Fridman JS, Hernando E, Hemann MT, de Stanchina E, Cordon-Cardo C, Lowe SW. Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA. The Mdm2 oncoprotein physically associates with p53 and antagonizes its tumor suppressor functions. Previous studies indicate that some tumors express alternatively or aberrantly spliced Mdm2 variants that are unable to bind p53, but whether these actively contribute to carcinogenesis or are a byproduct of cancer progression has been unclear. In this study, we examined the ability of full-length Mdm2 and several tumor-derived splice variants to modulate tumor development in E micro -myc transgenic mice. We report that several tumor-derived Mdm2 splice variants promote tumorigenesis in a manner that is comparable with full-length Mdm2. Our results imply that the current paradigm for understanding Mdm2 action during oncogenesis is incomplete, and its splice variants contribute to human cancer. PMID: 14522887 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 150: Zhonghua Bing Li Xue Za Zhi. 2003 Jun;32(3):271-3. [Molecular biological study of cerebellar medulloblastoma and supratentorial primitive neuroectodermal tumors] [Article in Chinese] Xuan Q, Xu QZ. Publication Types: Review Review, Tutorial PMID: 14518436 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 151: Arkh Patol. 2003 Jul-Aug;65(4):12-8. [Cytogenetic variants of dysregenerative and precancerous epithelial changes in chronic inflammatory pulmonary diseases] [Article in Russian] Kogan EA, Paramonova NB, Demura SA, Popova EN. I. M. Sechenov Moscow Medical Academy, 119881, Moscow. Surgical material of the lungs and their parts from 31 patients and open biopsies were studied. Proliferative activity (Ki-67, PCNA) and oncomarkers expression (bcl-2, p-53, c-myc, b-TGF, chromogranin-A) were studied immunohistochemically in the foci of various epithelial changes. It is established that a wide spectrum of alterations in pulmonary tissue is associated with variability of precursor cells and may have nosological features. PMID: 14518187 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 152: J Pathol. 2003 Oct;201(2):250-9. Beta-catenin accumulation in the progression of human hepatocarcinogenesis correlates with loss of E-cadherin and accumulation of p53, but not with expression of conventional WNT-1 target genes. Prange W, Breuhahn K, Fischer F, Zilkens C, Pietsch T, Petmecky K, Eilers R, Dienes HP, Schirmacher P. Institute of Pathology, University of Cologne, D-50931 Cologne, Germany. Beta-catenin integrates intracellular WNT signalling and the intercellular E-cadherin-catenin adhesion system. To date, little is known about the role of beta-catenin activation and nuclear accumulation in hepatocarcinogenesis. This study has analysed beta-catenin expression patterns in human dysplastic nodules (DNs), as well as in hepatocellular carcinomas (HCCs) in comparison with proliferation, expression of WNT-1 target genes, E-cadherin, and p53. One hundred and seventy HCCs and 25 DNs were categorized according to established criteria and analysed for the expression pattern of beta-catenin. Analysis of the proliferative activity and expression of E-cadherin, cyclin D1, MMP-7, c-myc, and p53 was performed on a representative subgroup of cases. All DNs lacked nuclear beta-catenin, while 36% of all HCCs were positive, with the number of nuclear stained cells ranging from less than 1% to more than 90%. Increasing nuclear accumulation of beta-catenin correlated with reduced membranous E-cadherin expression and nuclear p53 but not with proliferation. Cyclin D1, MMP-7, and c-myc expression was detected in 54%, 26%, and 65% of HCCs, respectively, but did not correlate with nuclear beta-catenin, proliferation, or grading. Sequence analysis of the beta-catenin gene revealed no detectable mutations in DNs, but mutations in the GSK-3beta binding site were present in 14.3% of the HCCs. In conclusion, this study has demonstrated that nuclear accumulation of beta-catenin is a frequent progression event in human hepatocarcinogenesis which correlates with nuclear p53 accumulation and loss of membranous E-cadherin, but not with the expression pattern of established WNT-1 target genes. It is hypothesized that the role of beta-catenin in human HCC differs significantly from its established function in colon carcinogenesis. Copyright 2003 John Wiley & Sons, Ltd. PMID: 14517842 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 153: Mol Cell Biol. 2003 Oct;23(20):7256-70. c-Myc augments gamma irradiation-induced apoptosis by suppressing Bcl-XL. Maclean KH, Keller UB, Rodriguez-Galindo C, Nilsson JA, Cleveland JL. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. Alterations in MYC and p53 are hallmarks of cancer. p53 coordinates the response to gamma irradiation (gamma-IR) by either triggering apoptosis or cell cycle arrest. c-Myc activates the p53 apoptotic checkpoint, and thus tumors overexpressing MYC often harbor p53 mutations. Nonetheless, many of these cancers are responsive to therapy, suggesting that Myc may sensitize cells to gamma-IR independent of p53. In mouse embryo fibroblasts (MEFs) and in E micro -myc transgenic B cells in vivo, c-Myc acts in synergy with gamma-IR to trigger apoptosis, but alone, when cultured in growth medium, it does not induce a DNA damage response. Surprisingly, c-Myc also sensitizes p53-deficient MEFs to gamma-IR-induced apoptosis. In normal cells, and in precancerous B cells of E micro -myc transgenic mice, this apoptotic response is associated with the suppression of the antiapoptotic regulators Bcl-2 and Bcl-X(L) and with the concomitant induction of Puma, a proapoptotic BH3-only protein. However, in p53-null MEFs only Bcl-X(L) expression was suppressed, suggesting levels of Bcl-X(L) regulate the response to gamma-IR. Indeed, Bcl-X(L) overexpression blocked this apoptotic response, whereas bcl-X-deficient MEFs were inherently and selectively sensitive to gamma-IR-induced apoptosis. Therefore, MYC may sensitize tumor cells to DNA damage by suppressing Bcl-X. PMID: 14517295 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 154: Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai). 2003 Oct;35(10):925-9. [Molecular pathological characteristics of human B-cell lymphomas induced by Epstein-Barr virus] [Article in Chinese] Gan RL, Yin ZH, Liu TF, Dong BH, Zhou JG, Yao KT. Cancer Research Institute, Nanhua University, Hengyang 421001, China. gan998@yahoo.com To identify molecular features of neoplasms associated with EB virus, human peripheral blood lymphocytes (huPBL) were isolated from healthy volunteer donors and were transplanted intraperitoneally into SCID mice, and then huPBL/SCID mice were infected with EB virus. Serum levels of human IgG were measured by unidirectional immunodiffusion assay. Human Alu sequence and EBER-1 in tumor tissues were detected with PCR and in situ hybridization. Immunohistochemical staining was used to examine leukocyte differentiation antigens (LCA, L26, UCHL1, PS1), viral gene products (LMP1, EBNA2, BZLF1) and cellular oncoproteins (p53, C-myc, Bcl-2 and Bax). The experiments showed that tumors developed in 24 of 34 surviving huPBL/SCID mice by EBV infection. Histopathological and immunohistochemical observations demonstrated that all of the induced tumors in SCID mice were malignant lymphomas derived from human B-lymphocytes. In situ hybridization showed that tumor cells had EBV-encoded small RNA-1 (i.e. EBER-1). Alu sequence could be amplified by PCR from human genome of tumor tissues. Immunohistochemistry detected positive staining of BZLF1-encoded protein in a small population of tumor cells of almost all cases, and positive staining of LMP1 and EBNA2 only in small number of tumor cells. Human IgG could be found in the serum of 12 SCID mice on the 15th day after huPBL engraftment, and then increased with time and with the development of induced tumors in 6 mice. Positive rates of p53, C-myc, Bcl-2 and Bax expression were 83.33%, 100%, 95.83%, 91.67%, respectively, in 24 cases of the EBV-induced lymphomas. The results indicate that molecular lesions associated with the induced B-cell lymphoma involved EBV infection, expression of oncogenic viral genes, and abnormal expression of cellular oncogenes in human xenografts. Human IgG level in the serum of huPBL/SCID mice can be considered as a useful index for tumor development. PMID: 14515211 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 155: Hua Xi Kou Qiang Yi Xue Za Zhi. 2003 Aug;21(4):274-6. [The experimental study on telomerase activity and expression of p53 and c-myc genes in tongue cancer] [Article in Chinese] Fang Z, Li H, Wang C. Department of Stomatology and Maxillofacial Surgery, Stomatological College, Fourth Military Medical University, Xi'an 710032, China. OBJECTIVE: To study telomerase activity and expression of oncogenes c-myc and p53 in tongue cancer, analyse the interaction among them, and assess their possible correlations with tongue cancer clinicopathological features. METHODS: To detective the telomerase activity by TRAP and examine the positive expression of c-myc and p53 in tongue cancer by hybridization in situ. RESULTS: A high telomerase activity existed in lower differentiated tongue cancer (P < 0.05); the positive expression of c-myc increased significantly in lower grade tongue cancer (P < 0.05) and the positive expression of p53 decreased increasingly in tongue cancer accompanied with lymph node metastasis (P < 0.05). CONCLUSION: Telomerase may play a key role in the tumorigenesis of tongue cancer. Meantime, c-myc and p53 exerts important effect on telomerase activation during the course of tongue cancer generation and development. PMID: 14513581 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 156: Genes Chromosomes Cancer. 2003 Nov;38(3):215-25. High-resolution mapping of amplifications and deletions in pediatric osteosarcoma by use of CGH analysis of cDNA microarrays. Squire JA, Pei J, Marrano P, Beheshti B, Bayani J, Lim G, Moldovan L, Zielenska M. Princess Margaret Hospital and The Ontario Cancer Institute, Toronto, Ontario, Canada. jeremy.squire@utoronto.ca Conventional cytogenetic and comparative genomic hybridization (CGH) studies have shown that osteosarcomas (OSs) are characterized by complex structural and numerical chromosomal alterations and gene amplification. In this study, we used high-resolution CGH to investigate recurrent patterns of genomic imbalance by use of DNA derived from nine OS tumors hybridized to a 19,200-clone cDNA microarray. In six OSs, there was copy number gain or amplification of 6p, with a minimal region of gain centering on segment 6p12.1. In seven OSs, the pattern of amplification affecting chromosome arm 8q showed high-level gains of 8q12-21.3 and 8q22-q23, with amplification of the MYC oncogene at 8q24.2. Seven OSs showed copy number gain or amplification of 17p between the loci bounded by GAS7 and PMI (17p11.2-17p12), and three of these tumors also showed small losses at 17p13, including the region containing TP53. An in silico analysis of the distribution of segmental duplications (duplicons) in this region identified a large number of tracts consisting of paralogous sequences mapping to the 17p region, encompassing the region of deletions and amplifications in OS. Interestingly, within this same region there were clusters of duplicons and several genes that are expressed during bone morphogenesis and in OS. In summary, microarray CGH analysis of the chromosomal imbalances of OS confirm the overall pattern observed by use of metaphase CGH and provides a more precise refinement of the boundaries of genomic gains and losses that characterize this tumor. Copyright 2003 Wiley-Liss, Inc. PMID: 14506695 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 157: Semin Cancer Biol. 2003 Jun;13(3):191-202. Higher grade transformation of follicular lymphoma: phenotypic tumor progression associated with diverse genetic lesions. Lossos IS, Levy R. Department of Hematology and Oncology, Sylvester Comprehensive Cancer Center, University of Miami, 1475 NW 12th Avenue (D8-4), Miami, FL 33136, USA. ilossos@med.miami.edu Higher grade histological transformation of follicular lymphoma (FL) to more aggressive diffuse large B-cell lymphomas (DLBCL) occurs in 10-60% of the cases. Review of the current knowledge of genetic and molecular alterations associated with the higher grade transformation of FCL suggests that the process that leads to clinically and phenotypically similar end-point can occur by functionally diverse genetic lesions. The most commonly identified genetic alterations associated with the FCL transformation are TP53 gene mutations, inactivation of CDKN2A and CDKN2B genes and deregulation of the C-MYC gene. These lesions affect different aspects of normal cell physiology (apoptosis, cell cycle control, and proliferation) and are potential targets for gene-specific therapies. Publication Types: Review Review, Tutorial PMID: 12959350 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 158: Sichuan Da Xue Xue Bao Yi Xue Ban. 2003 Apr;34(2):207-9. [The expression of mRNA and SDS-PAGE of L1210 cell strains and its cloned cells] [Article in Chinese] Liu Q, Lu Z, Wang X, Liu F. Department of Laboratory Animal, Hebei Medical University, Shijiazhuang 050017, China. OBJECTIVE: To examine the expression difference of mRNA of L1210 cell strains and its cloned cells and discuss the methods for quality control of cell strains. METHODS: We used SDS-PAGE to observe the difference of protein and performed in situ hybridization to examine the expression of mRNA with the use of 6 cDNA probes that were marked by biotin. RESULTS: The number of protein bands of L1210 from Beijing Cancer Institute was 32. The number of protein bands of the two cloned cells L3E11 and L3F9 was 31. The 6 cDNA probes (p16, c-fos, c-jun, c-myc, p21, and p53 mRNA) were found to be existing in Beijing Cancer Institute L1210 and two different cloned cell strains. Expression of c-myc, c-fos, p53 mRNA could distinguish L3E11 and L3F9 cloned cells. PMID: 12947690 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 159: Cancer Gene Ther. 2003 Sep;10(9):707-16. E6AP gene suppression and characterization with in vitro selected hammerhead ribozymes. Kim Y, Cairns MJ, Marouga R, Sun LQ. Department of Medicine, St Vincent's Hospital Clinical School, University of New South Wales, Sydney 2010, Australia. lsun2@medau.jnj.com E6AP was originally identified as the ubiquitin-protein ligase involved in human papillomavirus (HPV) E6-mediated p53 degradation and has since been shown to act as an E3 ubiquitin-protein ligase in the ubiquitination of several other protein substrates. To further define E6AP function at the molecular and cellular levels, a ribozyme-based gene inactivation approach was adopted. A library of hammerhead ribozymes, with randomized arm sequences, was used to screen active molecules along the entire E6AP transcript for ribozyme-cleavable sites. Ligation-anchored PCR was adapted to detect cleavage products, and ribozymes designed to the selected sites were characterized both in vitro and in vivo. Ribozyme-mediated reduction in E6AP expression was found to enhance the apoptotic response of HeLa cells to mitomycin C-induced DNA damage. These findings suggest that E6AP has potential as a drug target, as its suppression can potentiate apoptosis in HPV-positive cells treated with a cytotoxic drug. PMID: 12944990 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 160: Anticancer Res. 2003 Jul-Aug;23(4):3159-65. The effects of a growth-inhibiting tripeptide, acetylGlu-Ser-GlyNH2 (Ac-ESG), on gene expression and cell cycle progression of two lymphoma cell lines. Liu Y, Reichelt WH, Luna L, Elgjo K, Reichelt KL. Institute of Pediatric Research, National Hospital, University of Oslo, N-0027 Oslo, Norway. YL4@georgetown.edu BACKGROUND: We recently isolated and characterized a tripeptide, acetylGlu-Ser-GlyNH2 (Ac-ESG), which inhibits proliferation of lymphoid cells. In this paper we describe the effects of Ac-ESG on growth-related gene expression and cell cycle progression in two lymphoma cell lines, Ramos and Molt, representing B and T lymphocytes, respectively. MATERIALS AND METHODS: RNA was extracted from Molt and Ramos cells with or without the tripeptide treatment. Gene expression was examined by semi-quantitative RT-PCR and Northern blot hybridization, and cell cycle progression was detected by flow cytometry. RESULTS: In the Molt cells, p53 gene expression was increased following treatment while c-myc was decreased after treatment shorter than 24 hours; N-ras expression was significantly reduced at picomolar concentration for 24-hour treatment; cyclinD1 and cdk4 expression did not show any change; DNA flow cytometry demonstrated that Molt cells were arrested or delayed predominantly in G2-M. Untreated Ramos cells had higher gene expression levels of c-myc, N-Ras and cdk4 than Molt cells, but lower p53 expression. These cells were not sensitive to Ac-ESG. CONCLUSION: The tripeptide Ac-ESG alters the expression of several growth-related genes in the Molt cell line and brings about an arrest or delay of cells in G2-M. PMID: 12926049 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 161: Pathol Res Pract. 2003;199(6):445-50. Erratum in: Pathol Res Pract. 2003;199(10):686. Different mRNA expression profile during tumor progression in a well-differentiated liposarcoma--A microdissection approach. Schneider-Stock R, Gerresheim F, Kolin-Gerresheim I, Meyer F, Jager V, Epplen JT, Roessner A, Boltze C. Department of Pathology, Otto-von-Guericke University, Magdeburg, Germany. Regine.Schneider-Stock@medizin.uni-magdeburg.de Like malignant fibrous histiocytoma (MFH), dedifferentiated liposarcoma represents a distinct subtype of liposarcoma and is characterized by an abrupt transition from well-differentiated liposarcoma (WDL) to highgrade dedifferentiated liposarcoma (DDL) . In addition, specific cytogenetic aberrations support the close biological relationship between WDL and DDL. Recent observations indicated the significance of cell cycle aberrations in tumor progression from the low-malignant, well differentiated to its dedifferentiated form, the prognosis of which is poor. Thus, alterations of mdm2 and p53 genes belong to the most frequently reported alterations in these two subtypes of liposarcoma. In previous investigations, we reported that loss of heterozygosity at the Rb gene locus, telomerase activity, hTERT, and c-Myc expression were associated with tumor progression in liposarcomas. In this study, we report on a case of a WD/DDL, in which both tumor components were separated using laser microdissection (P.A.L.M.) for the investigation of hTERT mRNA expression on a LightCycler. Macroscopically selected and histologically proven cryosections of low malignant and highly malignant tumor areas were cytogenetically investigated to confirm the diagnosis and to find additional chromosomal alterations with tumor progression. Publication Types: Case Reports PMID: 12924448 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 162: Atherosclerosis. 2003 Aug;169(2):245-50. Cytotoxic effects of the lipid peroxidation product 2,4-decadienal in vascular smooth muscle cells. Cabre A, Girona J, Vallve JC, Heras M, Masana L. Unitat de Recerca de Lipids i Arteriosclerosi - Fundacio IRCIS, Facultat de Medicina, Universitat Rovira i Virgili, C. Sant Llorenc 21, 43201 Reus, Spain. It is well known that oxidized LDL can be cytotoxic to smooth muscle cells (SMC) and then contribute to the progression of atherosclerosis. Nevertheless, which oxidized compound and which mechanism are involved in cell death is still under study. In this work we have studied the role of two representative apolar aldehydes (hexanal and 2,4-decadienal (2,4-DDE)), derived from polyunsaturated fatty acids oxidation, on human SMC cytotoxicity. Cell cytotoxicity was assessed by means of lactate deshydrogenase (LDH) release, cell morphology and DNA fragmentation. Results showed that hexanal up to 50 microM for 24 h was not cytotoxic to cells. However, 2,4-DDE at 50 microM for 24 h induced a 48% LDH leakage. The observed cytotoxic effect of 2,4-DDE was not due to a programmed cell death as no DNA ladder was detected. After aldehydes exposition a decreased expression of p53 and c-myc mRNA, genes involved in cell death regulation, was also demonstrated by RT-PCR. These observations suggest that 2,4-DDE may be the molecular cause of lipid oxidation cytotoxicity to human vascular SMC. By inducing cell necrosis in advanced stages, lipid oxidation may contribute to the cell debris core which is growing in the atherosclerotic lesion leading to a weakened and unstable plaque. PMID: 12921975 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 163: Cell. 2003 Aug 8;114(3):371-83. H2AX haploinsufficiency modifies genomic stability and tumor susceptibility. Celeste A, Difilippantonio S, Difilippantonio MJ, Fernandez-Capetillo O, Pilch DR, Sedelnikova OA, Eckhaus M, Ried T, Bonner WM, Nussenzweig A. Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. Histone H2AX becomes phosphorylated in chromatin domains flanking sites of DNA double-strand breakage associated with gamma-irradiation, meiotic recombination, DNA replication, and antigen receptor rearrangements. Here, we show that loss of a single H2AX allele compromises genomic integrity and enhances the susceptibility to cancer in the absence of p53. In comparison with heterozygotes, tumors arise earlier in the H2AX homozygous null background, and H2AX(-/-) p53(-/-) lymphomas harbor an increased frequency of clonal nonreciprocal translocations and amplifications. These include complex rearrangements that juxtapose the c-myc oncogene to antigen receptor loci. Restoration of the H2AX null allele with wild-type H2AX restores genomic stability and radiation resistance, but this effect is abolished by substitution of the conserved serine phosphorylation sites in H2AX with alanine or glutamic acid residues. Our results establish H2AX as genomic caretaker that requires the function of both gene alleles for optimal protection against tumorigenesis. PMID: 12914701 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 164: Cell. 2003 Aug 8;114(3):359-70. Histone H2AX: a dosage-dependent suppressor of oncogenic translocations and tumors. Bassing CH, Suh H, Ferguson DO, Chua KF, Manis J, Eckersdorff M, Gleason M, Bronson R, Lee C, Alt FW. Howard Hughes Medical Institute, The Children's Hospital, Department of Genetics, Harvard Medical School and The Center for Blood Research, Boston, MA 02115, USA. We employed gene targeting to study H2AX, a histone variant phosphorylated in chromatin surrounding DNA double-strand breaks. Mice deficient for both H2AX and p53 (H(delta/delta)P(-/-)) rapidly developed immature T and B lymphomas and solid tumors. Moreover, H2AX haploinsufficiency caused genomic instability in normal cells and, on a p53-deficient background, early onset of various tumors including more mature B lymphomas. Most H2AX(delta/delta)p53(-/-) or H2AX(+/delta)p53(-/-) B lineage lymphomas harbored chromosome 12 (IgH)/15 (c-myc) translocations with hallmarks of either aberrant V(D)J or class switch recombination. In contrast, H2AX(delta/delta)p53(-/-) thymic lymphomas had clonal translocations that did not involve antigen receptor loci and which likely occurred during cellular expansion. Thus, H2AX helps prevent aberrant repair of both programmed and general DNA breakage and, thereby, functions as a dosage-dependent suppressor of genomic instability and tumors in mice. Notably, H2AX maps to a cytogenetic region frequently altered in human cancers, possibly implicating similar functions in man. PMID: 12914700 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 165: Oncogene. 2003 Aug 11;22(33):5208-19. Cell cycle regulation and neural differentiation. Galderisi U, Jori FP, Giordano A. Department of Experimental Medicine, School of Medicine, Second University of Naples, Naples, Italy. The general mechanisms that control the cell cycle in mammalian cells have been studied in depth and several proteins that are involved in the tight regulation of cell cycle progression have been identified. However, the analysis of which molecules participate in cell cycle exit of specific cell lineages is not exhaustive yet. Moreover, the strict relation between cell cycle exit and induction of differentiation has not been fully understood and seems to depend on the cell type. Several in vivo and in vitro studies have been performed in the last few years to address these issues in cells of the nervous system. In this review, we focus our attention on cyclin-cyclin-dependent kinase complexes, cyclin kinase inhibitors, genes of the retinoblastoma family, p53 and N-Myc, and we aim to summarize the latest evidence indicating their involvement in the control of the cell cycle and induction of differentiation in different cell types of the peripheral and central nervous systems. Studies on nervous system tumors and a possible contributory role in tumorigenesis of polyomavirus T antigen are reported to point out the critical contribution of some cell cycle regulators to normal neural and glial development. Publication Types: Review PMID: 12910258 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 166: Oncogene. 2003 Aug 7;22(32):4993-5005. Myc and E2F1 induce p53 through p14ARF-independent mechanisms in human fibroblasts. Lindstrom MS, Wiman KG. Department of Oncology-Pathology, Cancer Center Karolinska (CCK), R8:04, Karolinska Institutet, SE-171 76 Stockholm, Sweden. p19ARF is induced in response to oncogene activation or during cellular senescence in mouse embryo fibroblasts, triggering p53-dependent and p53-independent cell cycle arrest and apoptosis. We have studied the involvement of human p14ARF as a regulator of p53 activity in normal human skin fibroblasts (NHFs) or WI38 lung embryonic fibroblasts expressing conditional Myc or E2F1 estrogen receptor fusion proteins. Both Myc and E2F1 activation rapidly induced p53 phosphorylation at Ser-15, p53 protein accumulation, and upregulation of the p53 target genes MDM2 and p21. Activation of E2F1 induced p14ARF mRNA and protein levels. In contrast, Myc activation did not induce any significant increase in p14ARF mRNA or protein levels in neither NHFs nor WI38 fibroblasts within 48 h. Myc and E2F1 induced p53 and cell cycle arrest even after silencing of p14ARF using short-interfering RNA. Treatment with the ATM/ATR kinase inhibitor caffeine prevented p53 accumulation upon activation of Myc or E2F1. Our results indicate that p53 phosphorylation, but not p14ARF, plays a major role for the induction of p53 in response to Myc and E2F1 activation in normal human fibroblasts. PMID: 12902982 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 167: Oncol Rep. 2003 Sep-Oct;10(5):1329-35. Relationship between AgNORs, MIB-1 and oncogene expression in male breast carcinoma and papillary superficial bladder neoplasm. Pich A, Margaria E, Chiusa L, Bortolin P, Palestro G. Dipartimento di Scienze Biomediche e Oncologia Umana, Universita di Torino, I-10126 Torino, Italy. achille.pich@unito.it The expression of p53, c-erbB-2, bcl-2 and c-myc proteins was compared to the quantity of the nucleolar organiser regions (AgNORs) and MIB-1 antigen to elucidate the relationship between oncogene expression and rapidity of cell proliferation and tumor growth fraction. Sections from 50 male breast carcinomas (MBC) and 62 superficial papillary bladder neoplasias were stained with the standardised AgNOR method and monoclonal antibodies MIB-1, DO7, CB11, bcl-2 124 and 9E11. p53 immunopositivity was associated with high AgNOR quantity and MIB-1 scores both in MBC and bladder neoplasm. c-erbB-2 expression was associated with high AgNOR quantity in bladder neoplasm. bcl-2 expression was associated with low AgNOR quantity in MBC. c-myc expression was associated with high AgNOR quantity in MBC. MBC patients with low AgNOR quantity, and p53, c-erbB-2 and c-myc immunonegativity had the longest overall survival. Patients with bladder neoplasia with low AgNOR quantity, negative p53 and positive c-erbB-2 immunostaining had the longest disease-free survival time. Our results indicate that p53 overexpression reflects both the rapidity of cell proliferation, as assessed by AgNOR quantity, and tumor growth fraction, as assessed by MIB-1 scores, while c-erbB-2, c-myc and bcl-2 expression mainly reflects the rapidity of cell proliferation. The combination of AgNOR quantity and oncogene expression may stratify patients into different risk groups. PMID: 12883702 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 168: Cancer Lett. 2003 Jul 18;197(1-2):93-8. The p53 pathway and its inactivation in neuroblastoma. Tweddle DA, Pearson AD, Haber M, Norris MD, Xue C, Flemming C, Lunec J. Cancer Research Unit, The Medical School, University of Newcastle, Newcastle-upon-Tyne NE2 4HH, UK. d.a.tweddle@newcastle.ac.uk Early studies of p53 in neuroblastoma reported infrequent mutations in tumours and cell lines. Cytoplasmic sequestration was later proposed as an alternative mechanism of inactivation, but many studies have since reported an intact p53 pathway in neuroblastoma cell lines, as detected by nuclear p53 accumulation after DNA damage, intact DNA binding, transcriptional activation of target genes and the induction of apoptosis. In some MYCN amplified cell lines however, an irradiation induced G(1) arrest does not occur, despite the presence of normal p53. Neuroblastoma usually responds to chemotherapy but frequently relapses, and there is evidence from tumours, and cell lines that p53 inactivation via mutation or MDM2 amplification occurs at relapse and is sometimes associated with multidrug resistance. If p53 inactivation occurs frequently in relapsed tumours it may be appropriate to include p53 independent therapies in the initial management of high-risk neuroblastoma. Publication Types: Review Review, Tutorial PMID: 12880966 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 169: Am J Physiol Endocrinol Metab. 2003 Dec;285(6):E1273-81. Epub 2003 Jul 22. Acute and chronic effects of alcohol exposure on skeletal muscle c-myc, p53, and Bcl-2 mRNA expression. Nakahara T, Hashimoto K, Hirano M, Koll M, Martin CR, Preedy VR. Department of Chemistry, Faculty of Science, Kyushu University Ropponmatsu, Fukuoka 810-8560, Japan. Skeletal muscle atrophy is a common feature in alcoholism that affects up to two-thirds of alcohol misusers, and women appear to be particularly susceptible. There is also some evidence to suggest that malnutrition exacerbates the effects of alcohol on muscle. However, the mechanisms responsible for the myopathy remain elusive, and some studies suggest that acetaldehyde, rather than alcohol, is the principal pathogenic perturbant. Previous reports on rats dosed acutely with ethanol (<24 h) have suggested that increased proto-oncogene expression (i.e., c-myc) may be a causative process, possibly via activating preapoptotic or transcriptional pathways. We hypothesized that 1) increases in c-myc mRNA levels also occur in muscle exposed chronically to alcohol, 2) muscle of female rats is more sensitive than that from male rats, 3) raising acetaldehyde will also increase c-myc, 4) prior starvation will cause further increases in c-myc mRNA expression in response to ethanol, and 5) other genes involved in apoptosis (i.e., p53 and Bcl-2) would also be affected by alcohol. To test this, we measured c-myc mRNA levels in skeletal muscle of rats dosed either chronically (6-7 wk; ethanol as 35% of total dietary energy) or acutely (2.5 h; ethanol as 75 mmol/kg body wt ip) with ethanol. All experiments were carried out in male Wistar rats (approximately 0.1-0.15 kg body wt) except the study that examined gender susceptibility in male and female rats. At the end of the studies, rats were killed, and c-myc, p53, and Bcl-2 mRNA was analyzed in skeletal muscle by RT-PCR with an endogenous internal standard, GAPDH. The results showed that 1) in male rats fed ethanol chronically, there were no increases in c-myc mRNA; 2) increases, however, occurred in c-myc mRNA in muscle from female rats fed ethanol chronically; 3) raising endogenous acetaldehyde with cyanamide increased c-myc mRNA in acute studies; 4) starvation per se increased c-myc mRNA levels and at 1 day potentiated the acute effects of ethanol, indicative of a sensitization response; 5) the only effect seen with p53 mRNA levels was a decrease in muscle of rats starved for 1 day compared with fed rats, and there was no statistically significant effect on Bcl-2 mRNA in any of the experimental conditions. The increases in c-myc may well represent a preapoptotic effect, or even a nonspecific cellular stress response to alcohol and/or acetaldehyde. These data are important in our understanding of a common muscle pathology induced by alcohol. PMID: 12876071 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 170: Hematol J. 2003;4(4):263-70. Comparison between conventional banding analysis and FISH screening with an AML-specific set of probes in 260 patients. Cox MC, Panetta P, Venditti A, Del Poeta G, Franchi A, Buccisano F, Tamburini A, Maurillo L, Amadori S. Department of Hematology, University Tor Vergata, St. Eugenio Hospital, Rome, Italy. mccox@libero.it Fluorescence in situ hybridization (FISH) is becoming popular in the diagnosis of clonal chromosomal abnormalities. We set up a fast FISH procedure using an extensive set of specific probes. Conventional banding analysis (CBA) and FISH were compared in 260 newly diagnosed acute myeloid leukemia (AML) patients. For FISH the following probes were used: MLL, CBF-beta/MYH11, ETV-6/AML1; AML1/ETO, BCR/ABL, PML/RAR, c-MYC, TP53, RB1, 5q31/5p15.2, 5q33-34, 7q31/CEP7, 20q13; CEP 4, X, Y. Result time was 96 h for CBA versus 5 h for FISH from direct harvest. CBA showed clonal abnormalities in 41% (n=105/260), normal karyotype in 39% (n=102/260) and failed in 20% (n=53/260). FISH screened all patients and detected abnormalities in 39% (n=102/260); CBA and FISH together identified abnormalities in 49% (n=128/260). In six patients with normal CBA and in eight patients with clonal karyotype, it detected further cryptic abnormalities. CBA showed clonal abnormalities in 13% of patients negative at FISH (n=21/158). FISH screening does not add relevant information to CBA, but is the quickest method for detecting major genetic abnormalities in AML. The speed of FISH is very valuable in AML-M3/M3v because PML/RAR+ patients require specific therapy. Furthermore, we suggest FISH screening in failed, complex or suboptimal quality chromosome and specific FISH analysis for 5q, 7q, 12p, 17p, inv(16), t(11q23) in order to implement CBA accuracy. PMID: 12872151 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 171: Ai Zheng. 2003 Jul;22(7):771-4. [Research advances on inhibitor of apoptosis, survivin] [Article in Chinese] Yang J, Liu FX, Yan XC. Pathology Institute, Southwest Hospital, The Third Military Medical University, Chongqing, 400038, PR China. yangjing16@yahoo.com Survivin, a novel inhibitor of apoptosis, expressing in a cell cycle-dependent manner,regulates the G(2)/M phase of the cell cycle by associating with mitotic spindle microtubules; it directly inhibits caspase-3 and caspase-7activity. During tumorigenesis, survivin expression is inversely correlated with apoptosis and is positively correlated with proliferation and angiogenesis. Survivin expression up-regulation predicts short survival and poor prognosis in human cancers. Survivin targeting antisense nucleotide and survivin mutants induce apoptosis, reduce tumor growth potential, and sensitize tumor cells to chemotherapeutic drugs and X-irradiation in vitro and in vivo. These results suggest that survivin may has the potential function as a new target for the diagnosis and treatment of cancer. Publication Types: Review Review, Tutorial PMID: 12866973 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 172: Ann Oncol. 2003 Jul;14(7):1078-85. P21WAF1, P27KIP1, TP53 and C-MYC analysis in 204 ovarian carcinomas treated with platinum-based regimens. Plisiecka-Halasa J, Karpinska G, Szymanska T, Ziolkowska I, Madry R, Timorek A, Debniak J, Ulanska M, Jedryka M, Chudecka-Glaz A, Klimek M, Rembiszewska A, Kraszewska E, Dybowski B, Markowska J, Emerich J, Pluzanska A, Goluda M, Rzepka-Gorska I, Urbanski K, Zielinski J, Stelmachow J, Chrabowska M, Kupryjanczyk J. Department of Molecular Pathology, Institute of Oncology, Roentgena, Warsaw, Poland. BACKGROUND: The prognostic and predictive value of cell cycle regulatory proteins in ovarian cancer has not been established. We evaluated the clinical and biological significance of P21(WAF1), P27(KIP1), C-MYC, TP53 and Ki67 expressions in ovarian cancer patients. MATERIALS AND METHODS: Immunohistochemical analysis was performed on 204 ovarian carcinomas of International Federation of Gynecology and Obstetrics (FIGO) stage IIB to IV treated with platinum-based chemotherapy. Multivariate analysis with Cox and logistic regression models was performed in the whole group, and in the TP53-negative and TP53-positive subgroups. RESULTS: High P21(WAF1) labeling index (LI) was an independent positive predictor of platinum-sensitive response (P = 0.02). Overall survival was positively influenced by P21(WAF1) LI (P = 0.02) or by P21(WAF1) plus P27(KIP1) LI (P = 0.004) in the TP53-negative group only. Ki67 LI showed borderline association with disease-free survival (P = 0.05). Growth fraction was negatively associated with P21(WAF1) and P27(KIP1) indices in the TP53-negative group (P = 0.023 and 0.008, respectively), and these associations were borderline or lost in the TP53-positive group. Endometrioid and clear cell carcinomas differed from other carcinomas by having a low incidence of TP53 accumulation, a high incidence of C-MYC overexpression (70%) and a low median Ki67 LI (all with P <0.001). CONCLUSIONS: We have shown an independent predictive value of P21(WAF1) LI in ovarian carcinoma patients. The prognostic value of P21(WAF1) and P21(WAF1) plus P27(KIP1) LI was determined by TP53 status. A high frequency of C-MYC overexpression in endometrioid and clear cell carcinomas may suggest its role in the development of these tumor types. PMID: 12853350 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 173: Int J Mol Med. 2003 Aug;12(2):219-24. Cytogenetic and molecular genetic changes in malignant transformation of immortalized esophageal epithelial cells. Shen ZY, Xu LY, Chen MH, Cai WJ, Shen J, Chen JY, Zeng Y. Department of Pathology, College of Medicine, Shantou University, Shantou 515031, P.R. China. zhongyingshen@yahoo.com The purpose of this study was to evaluate the extent to which the expression of p53, c-myc, bcl-2, ras genes and chromosomes, along with activity of hTERT, impacts on the malignant transformation of immortalized esophageal epithelial cells. The SHEE cell line was established from an embryonic esophageal epithelial cell induced by transduction of E6E7 genes of human papillomavirus type 18 (HPV18E6E7). In cells of the 85th passage (SHEE85), the malignant transformation of SHEE was confirmed by morphology, cell proliferative index and tumor formation in SCID mice. C-myc, p53, bcl-2 and ras genes were assayed by the multi-PCR method with house-keeping gene GAPDH as control. The modal number of chromosomes was analyzed and its expression of subunit of telomerase, hTERT, was assessed by RT-PCR. Expression of HPV18E6E7 was assayed by Western blotting. The results showed that cells of SHEE85 were atypical and exhibited proliferative status with a proliferation index of 45.70%. Tumors formed in SCID mice with invasion of adjacent tissue. The karyotype belonged to hypotriploid and displayed expression of hTERT. C-myc, k-ras, bcl-2 and p53 (expression of phosphoprotein) were positive in SHEE85. Expression of HPV18E6E7 was positive. Taken together, SHEE85 cells were in fully malignant transformation and their molecular mechanism involved the expression of cellular genes, such as p53, bcl-2, c-myc and ras, and aberrance of chromosomes. It is probable that all of these changes were related with HPV18E6E7. PMID: 12851721 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 174: Cancer Genet Cytogenet. 2003 Jul 15;144(2):100-5. Cytogenetic study of malignant triton tumor: a case report. Haddadin MH, Hawkins AL, Long P, Morsberger LA, Depew D, Epstein JI, Griffin CA. Departments of Pathology and Oncology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street Carnegie 367, Baltimore MD 21287, USA. Malignant triton tumor (MTT) is a highly malignant neoplasm, classified as a variant of malignant peripheral nerve sheath tumor (MPNST) with rhabdomyoblastic differentiation. Few cytogenetic studies of MTT have been reported using conventional cytogenetic analysis. Here, we report a comprehensive cytogenetic study of a case of MTT using G-banding, Spectral Karyotyping(), and fluorescence in situ hybridization (FISH) for specific regions. A complex hyperdiploid karyotype with multiple unbalanced translocations was observed: 48 approximately 55,XY,der(7)add(7)(p?)dup(7)[2],der(7) t(7;20)(p22;?)ins(20;19)[5],der(7)ins(8;7)(?;p22q36)t(3;8)t(8;20)[15],-8[5],-8[1 9],r(8)dup(8), +der(8)r(8;22)[4],-9[9],der(11)t(11;20)(p15;?)ins(20;19)[22],der(12)t(8;12)(q21; p13)[21],der(13) t(3;13)(q25;p11),-17,-19,der(19)t(17;19)(q11.2;q13.1),-20,-22,+4 approximately 7r[cp24]/46,XY[13]. The 1995 International System for Human Cytogenetic Nomenclature was followed where possible. Note that breakpoints were frequently omitted where only SKY information was known for a small part of an involved chromosome. Our analysis revealed some breakpoints in common with those previously reported in MTT, MPNST, and rhabdomyosarcoma, namely 7p22, 7q36, 11p15, 12p13, 13p11.2, 17q11.2, and 19q13.1. FISH showed high increase of copy number for MYC and loss of a single copy for TP53. Publication Types: Case Reports PMID: 12850371 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 175: Int J Hematol. 2003 Jun;77(5):490-8. Clinical and genetic characteristics of Japanese Burkitt lymphomas with or without leukemic presentation. Namiki T, Sakashita A, Kobayashi H, Maseki N, Izumo T, Komada Y, Koizumi S, Shikano T, Kikuta A, Watanabe A, Suzumiya J, Kikuchi M, Kaneko Y. Departments of Cancer Chemotherapy, Saitama Cancer Center Hospital, Ina, Saitama, Japan. To clarify the clinical and genetic features of Burkitt lymphoma with or without leukemic presentation, we have conducted clinical, cytogenetic, and genetic studies. Of 40 Japanese patients with Burkitt lymphoma examined by cytogenetic and/or fluorescence in situ hybridization analysis or Southern blot analysis using MYC probes, 35 patients had t(8;14) translocations, and 5 had t(8;22). Breakpoints were located far upstream of MYC in 4 (12%) of 33 tumors with t(8;14), and Epstein-Barr virus infection was found in 3 (8%) of 40 tumors. These findings are similar to those reported for non-Japanese patients with the sporadic form of Burkitt lymphoma. Clinical and genetic characteristic were compared for 30 patients presenting with lymphoma and 10 presenting with leukemia. The overall survival was shorter in aggressively treated leukemia patients than in aggressively treated lymphoma patients (P = .003); however, the incidence rates of TP53 mutation, p16INK4a deletion, and p15INK4b deletion that were found in 6 (15%) of 40,3 (9%) of 35, and 2 (6%) of 35 tumors, respectively, were similar between the 2 subtypes. Thus, the present study has shown the different prognoses for the 2 subtypes of Burkitt lymphoma but has failed to clarify the genetic backgrounds that may explain the different outcomes. PMID: 12841388 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 176: Trends Mol Med. 2003 Jun;9(6):251-5. Recent advances in understanding apoptosis: new therapeutic opportunities in cancer chemotherapy. Makin G, Dive C. Cancer Research UK, Molecular and Cellular Pharmacology Group, School of Biological Sciences, University of Manchester, Manchester, UK M13 9PT. Major advances have been made in our understanding of the regulation of the molecular machinery of apoptosis in vitro. Molecules linking proliferation and apoptosis in healthy cells are being identified and here apoptotic cell death provides the 'fail-safe' mechanism to counteract excess proliferation. More recently, pioneering work on the regulation of apoptosis, in animal models of tumour development, has shown that suppression of apoptosis in the presence of a proliferative stimulus is sufficient for tumour development. Progress has also been made towards clarifying the contribution of drug-induced apoptosis to tumour response. With increasing evidence that failure to engage apoptosis after drug treatment contributes to drug resistance in vivo comes renewed confidence that new therapeutic approaches based on drug targets in apoptotic pathways will improve the treatment of cancer patients. As ever, tumour specificity is the major issue to be resolved. PMID: 12829013 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 177: Eur J Cancer. 2003 Jul;39(10):1478-85. Aberrant methylation of multiple genes in neuroblastic tumours. relationship with MYCN amplification and allelic status at 1p. Gonzalez-Gomez P, Bello MJ, Lomas J, Arjona D, Alonso ME, Aminoso C, Lopez-Marin I, Anselmo NP, Sarasa JL, Gutierrez M, Casartelli C, Rey JA. Laboratorio de Oncogenetica Molecular, Dept. C. Experimental, Hospital Universitario La Paz, Paseo de la Castellana 261, 28046, Madrid Spain. Aberrant hypermethylation occurs in tumour cell CpG islands and is an important pathway for the repression of gene transcription in cancers. We investigated aberrant hypermethylation of 11 genes by methylation-specific polymerase chain reaction (PCR), after treatment of the DNA with bisulphite, and correlated the findings with MYCN amplification and allelic status at 1p in a series of 44 neuroblastic tumours. This tumour series includes five ganglioneuromas (G), one ganglioneuroblastoma (GN) and 38 neuroblastomas (six stage 1 tumours; five stage 2 tumours; six stage 3 cases; 19 stage 4 tumours, and two stage 4S cases). Aberrant methylation of at least one of the 11 genes studied was detected in 95% (42 of 44) of the cases. The frequencies of aberrant methylation were: 64% for thrombospondin-1 (THBS1); 30% for tissue inhibitor of metalloproteinase 3 (TIMP-3); 27% for O6-methylguanine-DNA methyltransferase (MGMT); 25% for p73; 18% for RB1; 14% for death-associated protein kinase (DAPK), p14ARF, p16INK4a and caspase 8, and 0% for TP53 and glutathione S-transferase P1 (GSTP1). No aberrant methylation was observed in four control normal tissue samples (brain and adrenal medulla). MYCN amplification was found in 11 cases (all stage 4 neuroblastomas), whereas allelic loss at 1p was identified in 16 samples (13 stage 4 and two stage 3 neuroblastomas, and one ganglioneuroma). All but one case with caspase 8 methylation also displayed MYCN amplification. Our results suggest that promoter hypermethylation is a frequent epigenetic event in the tumorigenesis of neuroblastic tumours, but no specific pattern of hypermethylated genes could be demonstrated. PMID: 12826052 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 178: J Vet Sci. 2002 Dec;3(4):285-92. Sequence analysis of canine LINE-1 elements and p53 gene in canine transmissible venereal tumor. Choi YK, Kim CJ. Department of Clinical and Population Sciences College of Veterinary Medicine, University of Minnesota, St. Paul 55108, USA. LINEs (long interspersed nuclear elements or long interspersed repeated DNA elements) contains two open reading frames (ORFs), ORF1 and ORF2. We analysed the ORF2 located in the 5' region to the first exon of oncogene c-myc in canine transmissible venereal tumor (TVT) cell. We also showed the transcription activation was induced by this TVT-LINE sequence using CAT assay. To identify the mutation of tumor suppressor gene, sequence analysis of p53 from TVT cell was performed. We identified the point mutation of 964 nucleotide (T-C) resulting in the change of amino acid (Phe-Ser) of p53 tumor suppressor protein. PMID: 12825561 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 179: Breast Cancer Res. 2003;5(4):202-5. Epub 2003 May 30. Conditional mouse models demonstrate oncogene-dependent differences in tumor maintenance and recurrence. Tilli MT, Furth PA. Division of Human Genetics, University of Maryland, Baltimore, USA. Diversity in the pathophysiology of breast cancer frustrates therapeutic progress. We need to understand how mechanisms activated by specific combinations of oncogenes, tumor suppressors, and hormonal signaling pathways govern response to therapy and prognosis. A recent series of investigations conducted by Chodosh and colleagues offers new insights into the similarities and differences between specific oncogenic pathways. Expression of three oncogenes relevant to pathways activated in human breast cancers (c-myc, activated neu and Wnt1) were targeted to murine mammary epithelial cells using the same transgenic tetracycline-responsive conditional gene expression system. While the individual transgenic lines demonstrate similarly high rates of tumor penetrance, rates of oncogene-independent tumor maintenance and recurrence following initial regression are significantly different, and are modifiable by mutations in specific cooperating oncogenes or loss of tumor suppressor gene expression. The experiments make three notable contributions. First, they illustrate that rates of tumor regression and recurrence following initial regression are dependent upon the pathways activated by the initiating oncogene. The experiments also demonstrate that altered expression or mutation of specific cooperating oncogenes or tumor suppressor genes results in different rates of tumor regression and recurrence. Finally, they exemplify the power of conditional mouse models for elucidating how specific molecular mechanisms give rise to the complexity of human cancer. PMID: 12817992 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 180: Lin Chuang Er Bi Yan Hou Ke Za Zhi. 2003 Mar;17(3):161-3. [Significance of p53, c-myc and nm23 protein expression in recurrent laryngeal carcinoma] [Article in Chinese] Guo R, Huang D, Yang W, Han D. Department of Otolaryngology, PLA General Hospital, Beijing 100853. OBJECTIVE: To evaluate the prognosis of postoperative laryngeal cancer recurrence, the study was designed to investigate the relationship of p53, c-myc and nm23 protein expression in recurrent laryngeal carcinoma. METHOD: Five hundred and seventy-four cases of laryngeal carcinoma were retrospectively reviewed. All the patients were observed for 3 years postoperatively, 56 cases with recurrence were diagnosed and 39 cases of normal laryngeal tissue were compared. The tissue microarrays was made in all the cases. The tissue chip was analyzed by the SABC immunohistochemical method. RESULT: p53, c-myc and nm23 expressed in most of the laryngeal carcinoma. The positive ratio is different. There is higher expression of c-myc in recurrent laryngeal carcinoma, and its expression has significant difference with the laryngeal carcinoma, which have no recurrence (P < 0.01). nm23 has lower expression in recurrent laryngeal carcinoma, and it's expression has significant difference with the laryngeal carcinoma which have no recurrence(P < 0.01). The expression of p53 has no significant difference between recurrent laryngeal carcinoma and the laryngeal carcinoma which have no recurrence(P > 0.05). There is the positive correlation between the expression of c-myc and the recurrent laryngeal carcinoma; and negative correlation between the expression of nm23 and the recurrent laryngeal carcinoma. CONCLUSION: c-myc and nm23 could be the prognosis marker of postoperative laryngeal cancer recurrence. PMID: 12815897 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 181: Yi Chuan Xue Bao. 2003 Apr;30(4):321-4. [Study on the genetic alterations in MTX-resistant cells by differential polymerase chain reaction] [Article in Chinese] Zhang Y, Deng XY, Zhang XL, Zhang GY, Li P, Fu SB. Laboratory of Medical Genetics, Harbin Medical University, Harbin 150086, China. zhangyu@yahoo.com.cn Gene amplification is a common mechanism that contributes to the drug resistance. To explore the molecular genetic background related to the MTX resistance in the mouse MTX-resistant cells, differential PCR was used to determine the amplification and overexpression of DHFR gene. In addition, the correlations between c-myc, p53 status and dhfr amplification were studied. Amplification and overexpression of dhfr suggested its role in MTX-resistant cells. However, no amplification and overexpression of c-myc were detected. On the other hand, no alteration of p53 copy number was found. The increased mRNA level of p53 suggested the normal function of p53. These results implicated the status of c-myc and p53 had no correlation with dhfr amplification, therefore some other molecular genetic alterations may exist to permit the dhfr amplification in MTX-resistant cells. PMID: 12812055 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 182: Cancer Genet Cytogenet. 2003 Jul 1;144(1):76-9. An indolent B-cell lymphoma with t(2;8)(p12;q24) abnormality and absence of C-MYC amplification and TP53 deletion. A new variant? Potti A, Panwalkar A, Ingebretson MC, Tharapel SA, Goodell M, Dayton MV, Mehdi SA. Division of Hematology/Oncology, Veterans Affairs Medical Center, University of North Dakota School of Medicine, Fargo, ND 58102, USA. apotti@medicine.nodak.edu The translocation between chromosomes 2 and 8, t(2;8), is well known for its strong association with high-grade Burkitt lymphoma. However, the significance of this translocation in indolent lymphoproliferative disorders is not clear. We present the case of a 75-year-old white male with left upper quadrant abdominal pain, splenomegaly, and an elevated white cell count of 30.3x10(9) cells/L (84% large lymphoid cells with scanty cytoplasm and prominent central nucleoli). Immunophenotyping revealed a clonal B-cell population coexpressing CD5, CD19, and CD20 with weak CD23 and CD25 and very weak, restricted, surface lambda. The cytogenetic analysis showed all 20 cells with t(2;8)(p12;q24.3). In addition, four of the 20 cells also showed a second translocation: t(12;17)(p13;q21). Molecular analysis using c-myc and p53 probes showed normal results with no indication of amplification of C-MYC or deletion of TP53. The patient was managed as an indo-lent/low-grade lymphoproliferative disorder with excellent response to eight cycles of fludarabine. Publication Types: Case Reports PMID: 12810261 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 183: Exp Cell Res. 2003 Jul 1;287(1):178-89. Telomere maintenance and cell cycle regulation in spontaneously immortalized T-cell lines from Nijmegen breakage syndrome patients. Siwicki JK, Degerman S, Chrzanowska KH, Roos G. Department of Immunology, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland. Nijmegen breakage syndrome (NBS) is a rare genetic instability syndrome associated with a high incidence of lymphoid malignancies. The NBS1 protein has been implicated in telomere biology suggesting that cells from NBS patients might have deficient telomere maintenance capacity. In this study we characterized spontaneously immortalized T-cell lines derived from three NBS patients regarding growth characteristics, telomere biology, expression of cell-cycle regulators, and response to DNA damage to understand the role of NBS1 in the immortalization process. In all the NBS T-cell lines the acquisition of an immortal phenotype was associated with telomere length stabilization, high telomerase activity, and increased mRNA expression of the catalytic subunit of telomerase (hTERT), together with c-myc up-regulation. Our findings provide evidence that telomere length maintenance was intact in the T lymphocytes in the absence of a full-length NBS protein, presumably due to the presence of an alternatively transcribed NBS protein of 70 kDa. Normal protein expression patterns for pRb and p53 in all the immortal lines coincided with altered expression of some cell-cycle proteins as well as with an impaired G1/S arrest after gamma irradiation, despite a seemingly normal p53/p21 pathway. The here described, spontaneously immortalized NBS derived T-cell lines can be useful in future analysis of the biologic effects in the NBS. PMID: 12799193 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 184: Pathol Biol (Paris). 2003 Apr;51(3):176-84. [Genic alterations in oral and head and neck squamous cell carcinomas: analysis of international literature] [Article in French] Raybaud H, Odin G, Fafet A, Santini J, Monteil RA. Laboratoire de pathobiologie orale, universite de Nice, 24, avenue des Diables-Bleus, 06357 Nice cedex 4, France. raybaud@unice.fr The development of oral and head and neck squamous cell carcinomas occurs in relation with multiple events including mainly: loss of cycle cell control, evasion from apoptosis, telomerase reactivation. Complex interactions between a set of molecules, cell cycle proteins, tumour suppressor genes, oncogenes and the telomerase, occur in the multiple step process of carcinogenesis. The 2 main ways of control of the cell cycle rely on 2 tumour suppressor genes: the P53 gene and the retinoblastoma gene or RB gene. One of the regulation pathways or the 2 regulation pathways are disabled during the development of oral and head and neck squamous cell carcinomas. Most of the time, the inactivation of the P53 pathway results from a loss of function of the p53 protein, secondary to mutation and/or deletion of the P53 gene; It may also result of the amplification of the MDM2 gene and of the inactivation of the arf protein. The RB pathway leads to cell proliferation by loss of the p16 protein, by amplification of the cyclin D1 gene and less frequently by mutation of the RB gene or loss of the retinoblastoma protein. In India and South-East Asia, the activation of RAS and MYC oncogenes appears to be related with the presence of specific carcinogens in snuff and tobacco. By blocking apoptosis, the Bcl2 protein seems to increase the resistance of tumours to radiotherapy and chemotherapy. Publication Types: Review Review, Tutorial PMID: 12781800 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 185: Cold Spring Harb Symp Quant Biol. 2000;65:499-510. DNA damage responses and chemosensitivity in the E mu-myc mouse lymphoma model. Schmitt CA, Wallace-Brodeur RR, Rosenthal CT, McCurrach ME, Lowe SW. Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA. PMID: 12760067 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 186: Ai Zheng. 2003 May;22(5):458-62. Ribozyme targeted on HPV16E6 mRNA induced apoptosis on human cervical carcinoma CaSKi cells. Zheng YF, Zhang JR. Oncology Center, Zhujiang Hospital, The First Military Medical University, Guangzhou, Guang dong, PR China. zyfcn@yahoo.com BACKGROUND & OBJECTIVE: Human papillomavirus is related to cervical cancer. Ribozyme is special kind of RNA that can cleave target RNA. The aim of this study was to investigate the characterization of the cultured cervical cancer cell line transfected with anti-HPV16E6-ribozyme (HRz) and the effect of ribozyme on proliferation and apoptosis of cervical cancer cell. METHODS: Ribozyme targeted on HPV16E6 mRNA was designed using computer. With the method of lipofectin transfection, the anti-HPV16E6- ribozyme and empty eucaryotic expressing plasmids were transfected into the CaSKi cells, which named as CaSKi-R and CaSKi-P, respectively. The expression of E6 mRNA in the three kinds of cells was examined by Northern blot analysis. Cell cycle was determined using flow cytometry. Cell apoptosis rate was examined using fluorescent (Hoechst) staining and TUNEL (TDT-mediated dUTP nick end labeling).The expression of certain proteins, including HPV16E6, c-myc, bcl-2, p53, and Fas, were also determined using flow cytometry. RESULTS: RNA dot blot analysis demonstrated that HRz mRNA expressed stably in the CaSKi-R cells. Northern blot analysis showed that the expression of E6 mRNA was much lower in the CaSKi-R cells than that in the CaSKi cells, while there was no difference of E6 mRNA levels between the CaSKi cells and the CaSKi-P cells. The apoptosis rate in the CaSKi-R cells was much higher than that in the CaSKi cells and the CaSKi-P cells. The cell cycle was arrested in G2 phase, with decrease in percentage of S phase cells. Anti-HPV16E6-ribozyme can significantly reduce the expression of E6, c-myc, and bcl-2 genes in the CaSKi-R cells, and increase the expression of p53 compared with that in Caski cells. This phenomenon was not found in the CaSKi-P cells. The expression of Fas was similar in the three kinds of cells. CONCLUSION: Ribozyme targeted on HPVE6 mRNA can induce apoptosis of human cervical cancer CaSKi cells. The reason may be the decrease of expression of E6 gene, and the successive changes of expression of some genes, including c-myc, bcl-2, and p53 genes. PMID: 12753702 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 187: J Biol Chem. 2003 Aug 29;278(35):32507-16. Epub 2003 May 13. p21/CDKN1A mediates negative regulation of transcription by p53. Lohr K, Moritz C, Contente A, Dobbelstein M. Institut fur Virologie, Philipps-Universitat Marburg, Robert Koch Str. 17, 35037 Marburg, Germany. The tumor suppressor p53 regulates transcription positively and negatively, depending on the target gene. Whereas p53 induces transcription through direct interaction with promoter DNA, the mechanism of p53-mediated transcriptional repression is less well understood. Early reports described the alleviation of p53-mediated repression by inhibitors of apoptosis, suggesting that negative regulation of transcription might occur only in conjunction with programmed cell death. More recently, it has been proposed that certain genes, such as survivin, are repressed by direct association of p53 with their promoters, followed by recruitment of a repressor complex. We show here that p53-mediated negative regulation of transcription could occur independently of apoptosis. In contrast, the amino-terminal transactivation domain of p53 was required for negative regulation of transcription. Similarly, the p53 homologue p73 diminished the expression of survivin and stathmin, depending on its transactivation domain. Mutation of the putative p53 binding site within the survivin promoter did not impair its repression. These observations raised the hypothesis that activation of an effector gene might be required for repression by p53. Strikingly, when the p53-inducible p21/CDKN1A gene was deleted, p53 no longer repressed any one among 11 genes that it down-regulates otherwise. Most of these genes were also repressed by ectopic p21 in the absence of p53. Overexpressed c-Myc reduced the transcription of p21/CDKN1A and impaired p53-mediated repression but did not abolish repression by ectopic p21. Taken together, these results strongly suggest that increased expression of p21/CDKN1A is necessary and sufficient for the negative regulation of gene expression by p53. PMID: 12748190 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 188: Cancer Genet Cytogenet. 2003 May;143(1):50-8. Genomic rearrangements involving rDNA and centromeric heterochromatin in vulvar epidermoid carcinoma cell line A-431. Pedrazzini E, Mamaev N, Yakovleva T, Sukhikh T, Salido M, Sole F, Prat E, Camps J, Miro R, Slavutsky I. Departamento de Genetica, Instituto de Investigaciones Hematologicas "Mariano R. Castex," Academia Nacional de Medicina, Pacheco de Melo 3081, Buenos Aires 1425, Argentina. epedrazzini@hotmail.com The cytogenetic and molecular cytogenetic characterization of the human cell line A-431 derived from a vulvar epidermoid carcinoma is presented. A combination of karyotyping, fluorescence in situ hybridization (FISH) with chromosome- and/or region-specific probes, M-FISH, RxFISH, and comparative genomic hybridization (CGH) analysis was used. Six marker chromosomes with rearrangements involving insertions of single or double nucleolar organizing regions (NORs) and/or homogeneously staining regions containing active and overexpressed NORs and regions of centromeric heterochromatin were found: der(6), der(7), der(17), der(21), dic(13;14), and dic(14;18). The chromosomal origin of 14 other marker chromosomes was elucidated. Amplification of the C-MYC oncogene at 8q24 was revealed in two marker chromosomes: dup(8)(q24) and der(15)t(8;15)(q22;p11). Confirming previous reports, amplification of the cyclin D1 gene within an abnormal chromosome 11, that is, der(11)t(7;11)(p15;q21), was also detected. Loss of the TP53 tumor suppressor gene was evidenced over two der(17). Good concordance was found among karyotyping, FISH analysis, and CGH. Although reasons for NOR amplification or ectopic location in the epidermal carcinoma A-431 cell line are not clear yet, our data suggest that these phenomena play a supporting role with regard to other amplified genes. Thus, the A-431 cell line would be an appropriate model to study the different mechanisms involved in human tumorigenesis. PMID: 12742156 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 189: Eur Arch Otorhinolaryngol. 2003 Oct;260(9):502-8. Epub 2003 May 8. Molecular pathogenesis of head and neck squamous cell carcinoma. Hardisson D. Department of Pathology, Hospital Universitario La Paz, Universidad Autonoma de Madrid, Paseo de la Castellana 261, 28046 Madrid, Spain. dhardisson.hulp@salud.madrid.org Head and neck squamous cell carcinoma (HNSCC) represents 6% of all cancers. The overall 5-year survival rate for patients with this type of cancer is among the lowest of the major cancer types and has not improved dramatically during the last decade. The pathological staging, in particular the nodal stage, is the most important factor in HNSCC. The lack of progress in head and neck oncology emphasizes the importance of molecular genetic studies to define alterations that may correlate with tumor behavior. The molecular alterations observed in HNSCC are mainly due to oncogene activation and tumor suppressor gene inactivation, leading to deregulation of cell proliferation. These alterations include gene amplification and overexpression of oncogenes such as ras, myc, EGFR and cyclin D1, and mutations and deletions leading to p16 and TP53 tumor suppressor genes inactivation. This article reviews the molecular changes commonly observed in HNSCC. The biological function of these markers and the potential clinical application are discussed. Advances in the understanding of the molecular basis of HNSCC will help in the identification of new molecular markers that could be used for a more accurate diagnosis and assessment of prognosis and may open the way for novel approaches to treatment and prevention. Publication Types: Review Review, Tutorial PMID: 12736744 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 190: Cell Cycle. 2003 May-Jun;2(3):181-4. Direct regulation of RNA polymerase III transcription by RB, p53 and c-Myc. Felton-Edkins ZA, Kenneth NS, Brown TR, Daly NL, Gomez-Roman N, Grandori C, Eisenman RN, White RJ. Institute of Biomedical and Life Sciences, Division of Biochemistry and Molecular Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, UK. The synthesis of tRNA and 5S rRNA by RNA polymerase (pol) III is cell cycle regulated in higher organisms. Overexpression of pol III products is a general feature of transformed cells. These observations may be explained by the fact that a pol III-specific transcription factor, TFIIIB, is strongly regulated by the tumor suppressors RB and p53, as well as the proto-oncogene product c-Myc. RB and p53 repress TFIIIB, but this restraint can be lost in tumors through a variety of mechanisms. In contrast, c-Myc binds and activates TFIIIB, causing potent induction of pol III transcription. Using chromatin immunoprecipitation and RNA interference, we show that c-Myc interacts with tRNA and 5S rRNA genes in transformed cervical cells, stimulating their expression. Availability of pol III products may be an important determinant of a cell's capacity to grow. The ability to regulate pol III output may therefore be integral to the growth control functions of RB, p53 and c-Myc. Publication Types: Review Review, Tutorial PMID: 12734418 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 191: Nat Rev Cancer. 2003 May;3(5):350-61. The circadian clock: pacemaker and tumour suppressor. Fu L, Lee CC. Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA. The circadian rhythms are daily oscillations in various biological processes that are regulated by an endogenous clock. Disruption of these rhythms has been associated with cancer in humans. One of the cellular processes that is regulated by circadian rhythm is cell proliferation, which often shows asynchrony between normal and malignant tissues. This asynchrony highlights the importance of the circadian clock in tumour suppression in vivo and is one of the theoretical foundations for cancer chronotherapy. Investigation of the mechanisms by which the circadian clock controls cell proliferation and other cellular functions might lead to new therapeutic targets. Publication Types: Review Review, Tutorial PMID: 12724733 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 192: Mol Cell. 2003 Apr;11(4):905-14. Myc-mediated proliferation and lymphomagenesis, but not apoptosis, are compromised by E2f1 loss. Baudino TA, Maclean KH, Brennan J, Parganas E, Yang C, Aslanian A, Lees JA, Sherr CJ, Roussel MF, Cleveland JL. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. Myc and E2f1 promote cell cycle progression, but overexpression of either can trigger p53-dependent apoptosis. Mice expressing an Emu-Myc transgene in B lymphocytes develop lymphomas, the majority of which sustain mutations of either the Arf or p53 tumor suppressors. Emu-Myc transgenic mice lacking one or both E2f1 alleles exhibited a slower onset of lymphoma development associated with increased expression of the cyclin-dependent kinase inhibitor p27(Kip1) and a reduced S phase fraction in precancerous B cells. In contrast, Myc-induced apoptosis and the frequency of Arf and p53 mutations in lymphomas were unaffected by E2f1 loss. Therefore, Myc does not require E2f1 to induce Arf, p53, or apoptosis in B cells, but depends upon E2f1 to accelerate cell cycle progression and downregulate p27(Kip1). PMID: 12718877 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 193: Anticancer Res. 2003 Jan-Feb;23(1A):167-78. Pim-1 protein kinase is nuclear in Burkitt's lymphoma: nuclear localization is necessary for its biologic effects. Ionov Y, Le X, Tunquist BJ, Sweetenham J, Sachs T, Ryder J, Johnson T, Lilly MB, Kraft AS. University of Colorado Health Sciences Center, Division of Medical Oncology, Denver, Colorado 80262, USA. BACKGROUND: The Pim-1 33-kDa protein is a serine/threonine protein kinase that is capable of enhancing the rate of occurrence of c-Myc-induced lymphomas, and functions to block factor-withdrawal and genotoxic stress-induced apoptosis. MATERIALS AND METHODS: We used human lymphoma samples and tissue culture cells to examine the cellular location of this protein and its mechanism of action. RESULTS: We found that Pim-1 can be located in the cytoplasm, the cytoplasm and nucleus, or the nucleus of cells of normal lymph nodes, but is only located in the nucleus in Burkitt's lymphoma cells. On transfection of Pim-1 into HeLa cells, a nuclear localization is observed that is not dependent upon kinase activity, but appears to be regulated by the carboxy terminal half of the protein. Because Pim-1 is known to regulate apoptosis and human Mdm2 (HDM2) contains a consensus Pim-1 phosphorylation site, the possible role of Pim-1 in modulating HDM2 was examined. When Pim-1 and HDM2 are transfected transiently into 293 cells, the presence of Pim-1 results in an increase in the levels of the HDM2 protein. This effect requires the presence of the entire HDM2 protein. Export of Pim-1 out of the nucleus by attachment of a nuclear export signal decreased its ability to regulate the levels of HDM2 protein. CONCLUSION: The nuclear location of Pim-1 is essential for its regulation of the levels of HDM2 protein, and possibly for additional biological activities of this protein kinase. PMID: 12680209 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 194: Arch Pathol Lab Med. 2003 Apr;127(4):424-31. Characterization of 4 mantle cell lymphoma cell lines. Amin HM, McDonnell TJ, Medeiros LJ, Rassidakis GZ, Leventaki V, O'Connor SL, Keating MJ, Lai R. Department of Hematopathology, The University of Texas M. D. Anderson Cancer Center, Houston 77030, USA. CONTEXT: Mantle cell lymphoma (MCL) is a distinct type of B-cell non-Hodgkin lymphoma characterized by t(11;14)(q13;q32) and cyclin D1 overexpression. The pathogenesis of MCL has not been comprehensively studied, which can be attributed in part to the paucity of well-characterized MCL cell lines. OBJECTIVES: We collected 4 previously developed MCL cell lines and performed extensive characterization, including the susceptibly of these cell lines to transduction by adenovirus vectors. Our aim was to facilitate the establishment of an in vitro model that can be reliably used to study the pathogenesis of MCL. METHODS: Standard techniques were used to compare the morphologic, immunophenotypic, and cytogenetic features of the 4 cell lines. In addition, Western blotting was used to investigate the presence of several cell cycle- and apoptosis-related proteins. TP53 DNA sequencing was also performed on the cell lines. The adenoviral transduction efficiency was assessed using an adenoviral vector carrying the gene encoding for the green fluorescence protein (Ad-GFP). RESULTS: All cell lines demonstrated evidence of t(11;14)(q13;q32) and overexpression of cyclin D1. Cyclin D2 was not detectable in all cell lines, whereas cyclin D3 was weakly expressed in JeKo-1 and SP-53. Other abnormalities of the cell cycle G1 phase regulatory pathway were detected, including loss of expression of p53 (JeKo-1) and p16(INK4a) (SP-53 and Granta 519), as well as TP53 mutation (Mino). All cell lines express high levels of cyclin E, c-Myc, Bcl-2, Bax, Bcl-x(L), and Mcl-1. Retinoblastoma protein is hyperphosphorylated in all cell lines. With the exception of Mino, MCL cell lines are highly transducible with adenoviral vectors. CONCLUSION: These cell lines are representative of MCL and can be used as an in vitro model to further explore the pathogenesis of this disease. The susceptibility of these cell lines to gene transfer provides opportunities to evaluate the importance of various oncogenes and tumor suppressor genes that may have an impact on developing effective therapeutic regimens for MCL. PMID: 12683869 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 195: J Cancer Res Clin Oncol. 2003 Feb;129(2):89-99. Epub 2003 Feb 26. Cytogenetics and cytology of retinoblastomas. Bartova E, Kozubek S, Gajova H, Jirsova P, Zluvova J, Taslerova R, Koutna I, Kozubek M. Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65, Brno, Czech Republic. PURPOSE: Chromosomal aberrations and the nuclear topography of retinoblastoma tumour cells as well as lymphocytes of patients suffering from the familiar or sporadic form of retinoblastoma were studied. METHODS: Fluorescence in situ hybridisation (FISH) on fresh, paraffin-embedded tumour tissues and on peripheral blood leukocytes was used for cytogenetic analysis. The cell cycle profile and induction of apoptosis was studied by flow cytometry and gene expression changes were detected by RT-PCR. RESULTS: Using the repeated FISH technique, the average distances between the nuclear membrane and the fluorescence gravity centre (FGC) of seven selected chromosomes were determined in the same tumour population and three other cell types. Chromosome order in positioning from the nuclear membrane was similar in all cell populations investigated. Our experimental studies were focused on specific genetic loci relevant for retinoblastoma tumour pathogenesis. We revealed a certain heterogeneity in the copy number of the Rb1, N-myc, and TP53 gene loci in tumour cells. In addition, in lymphocytes isolated from peripheral blood of the patients, a high degree of copy number heterogeneity was also detected. In 60% of analysed retinoblastomas we observed numerical aberration involving the centromeric region of chromosome 6. In these tumours, apoptotic bodies were found irrespective of clinical therapy. Chromosome instability seems to be a typical feature of primary retinoblastomas as well as of the human pseudodiploid cell line Y79. These cells, of a hereditary form of retinoblastoma (Y79), were irradiated by gamma rays and exposed to anti-tumour drugs such as etoposide, vincristine, and cisplatin. These treatments induced apoptosis, changes in the cell cycle profile, and specific modifications in the nuclear topography of selected loci. Treatment with a non-lethal concentration of hydroxyurea was shown to induce the loss of the amplified N-myc gene involved in the homogenously staining region (HSR) that was found to be associated with the nuclear membrane of retinoblastoma Y79 cells. CONCLUSIONS: We assume that not only cytological and cytogenetic parameters but also aberrant chromatin structures and their nuclear topography can be useful tools for optimal tumour marker specification. PMID: 12669233 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 196: Yi Chuan Xue Bao. 2002;29(11):983-9. [A novel system for characterization of the transcription activating proteins in mammalian cells] [Article in Chinese] Zhang H, Zhou JG, Li JZ, Wang J, Sun YL, Chen S, Huang CF. Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100850, China. zhoujgx@public.bta.net.cn A system used for detecting the transcriptional activating activity of the function-unknown gene products in mammalian cells was developed. Based on the plasmid pTet-Off and the eukaryotic expressing vector pCDNA3.1B(-)/myc-his, firstly, we constructed a set of recombinant plasmids namely pZHO1 (for cloning into the foreign gene fragment and as a negative control), pZHO2 (as a positive control). The system also includes the plasmids pTRE-luc (encoding the Firefly luciferase reporter gene) and pRL-TK (encoding Renilla luciferase gene as background control). To confirm the feasibility of the system, the plasmids pZHO1, pZHO2 and pZHO3 (encoding p53 transcriptional activating domain, containing 73 amino acids in its N terminal) was contransfected into such mammalian cells as C4-2, MCF-7, COS7 respectively, each with pTRE-luc and pRL-TK plasmids, the feasibility of the system was determined by comparing the relative activity of Firefly luciferase activity ratio of and Renilla in different transfecting panels. Our research result showed that the system we constructed can be used for detecting the transcriptional activating activity of the target protein molecules in mammalian cells. PMID: 12645261 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 197: Exp Hematol. 2003 Mar;31(3):251-60. Profiling of differentially expressed apoptosis-related genes by cDNA arrays in human cord blood CD34+ cells treated with etoposide. Tao W, Hangoc G, Hawes JW, Si Y, Cooper S, Broxmeyer HE. Department of Microbiology and Immunology, Walther Oncology Center, Indiana University School of Medicine, Indianapolis, Ind 46202-5254, USA. wetao@iupui.edu OBJECTIVE: Understanding the molecular events that contribute to survival of and drug-induced apoptosis in hematopoietic stem and progenitor cells (HSC/P) can have impact on more rational approaches to blood cancer therapeutic design, as well as on strategies to minimize toxic side effects of chemotherapeutic drugs. Here we sought to systematically evaluate the basic molecular components and main pathways that govern and mediate cellular response initiated within human CD34(+) cells to etoposide-induced apoptosis. MATERIALS AND METHODS: Human CD34(+) cells were isolated from umbilical cord blood (CB) and expanded in vitro. Expression of apoptosis-related genes in the control and etoposide treated cells was determined using cDNA array and quantitative real-time RT-PCR. RESULTS: We identified a set of apoptosis-related genes expressed in highly purified normal human CB CD34(+) cells and determined how the expression of these genes changed in response to etoposide treatment. In addition, TRAIL does not induce apoptosis of normal human CD34(+) cells, and it has no cytotoxic effect on human CD34(+) cells that are undergoing apoptosis in response to growth factor withdrawal. This may be due to upregulation of cytotoxic receptors as well as the decoy receptor for TRAIL, and c-FLIP. CONCLUSION: p53, c-Myc, and BAFF pathways are main pathways utilized by CD34(+) cells to arrest cell-cycle progression at multiple checkpoints, to halt proliferation, and to induce apoptosis as part of their cellular response to etoposide. Multiple known pro-survival and pro-apoptotic pathways are simultaneously activated in etoposide-treated CD34(+) cells. Also, TRAIL, used alone or in concert with chemotherapeutic drugs, may be of use as a safe blood cancer therapeutic with no or low toxicity for HSC/P. Copyright 2003 International Society for Experimental Hematology PMID: 12644023 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 198: Endocrinology. 2003 Apr;144(4):1249-56. Dynamics of Myc/Max/Mad expression during luteinization of primate granulosa cells in vitro: association with periovulatory proliferation. Chaffin CL, Brogan RS, Stouffer RL, VandeVoort CA. Department of Physiology, Medical College of Georgia, Augusta, Georgia 30912, USA. cchaffin@mail.mcg.edu Granulosa cell luteinization involves the attenuation of gonadotropin-induced proliferation. Although recent evidence indicates that primate granulosa cells stop dividing within 12 h of an ovulatory stimulus, early events in cell cycle arrest remain unknown. In the current study an in vitro model of primate granulosa cell luteinization is established that allows assessment of early events in terminal differentiation. A luteinizing dose of human chorionic gonadotropin (hCG) results in a secondary rise in proliferation before cell cycle arrest that is paralleled by a transient increase in the expression of c-Myc. In contrast, the c-Myc antagonists Mad1, Mad4, and Mxi1 are transiently repressed by hCG. Max, the common dimerization partner for Myc and Mad, is similarly repressed by hCG, suggesting that changes in the expression of this gene may further regulate the activity of Myc and Mad. To determine whether other cell cycle regulatory families are involved in luteinization, the expression of p53 and the wild-type p53-inducible phosphatase (wip1) was examined. Similar to Mad and Max, p53 and wip1 are transiently repressed by hCG, suggesting that the p53 and Mad pathways have either parallel or cooperative roles in luteinization. Thus, luteinization of primate granulosa cells is preceded by a burst of proliferation that is regulated by changes in the relative levels of c-Myc, Max, and Mad as well as p53. PMID: 12639907 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 199: EMBO J. 2003 Mar 17;22(6):1442-50. Mdm2 haplo-insufficiency profoundly inhibits Myc-induced lymphomagenesis. Alt JR, Greiner TC, Cleveland JL, Eischen CM. Eppley Institute for Cancer Research, Department of Pathology and Microbiology, 987696 University of Nebraska Medical Center, Omaha, NE 68198, USA. Mdm2 harnesses the p53 tumor suppressor, yet loss of one Mdm2 allele in Mdm2(+/-) mice has heretofore not been shown to impair tumor development. Here we report that Mdm2 haplo-insufficiency profoundly suppresses lymphomagenesis in E micro -myc transgenic mice. Mdm2(+/-)E micro -myc transgenics had greatly protracted rates of B cell lymphoma development with life spans twice that of wild-type transgenic littermates. Im paired lymphoma development was associated with drastic reductions in peripheral B cell numbers in Mdm2(+/-)E micro -myc transgenics, and primary pre-B cells from Mdm2(+/-)E micro -myc transgenics and Mdm2(+/-) littermates were extremely susceptible to spontaneous apoptosis. Loss of p53 rescued all of the effects of Mdm2 haplo-insufficiency, indicating they were p53 dependent. Furthermore, half of the lymphomas that ultimately emerged in Mdm2(+/-)E micro -myc transgenics harbored inactivating mutations in p53, and the majority overcame haplo-insufficiency by overexpressing Mdm2. These results support the concept that Mdm2 functions are rate limiting in lymphomagenesis and that targeting Mdm2 will enhance p53-mediated apoptosis, compromising tumor development and/or maintenance. PMID: 12628936 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 200: Nat Rev Cancer. 2003 Mar;3(3):179-92. Does the ribosome translate cancer? Ruggero D, Pandolfi PP. Molecular Biology Program, Department of Pathology, Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Institute, 1275 York Avenue, New York, New York 10021, USA. Ribosome biogenesis and translation control are essential cellular processes that are governed at numerous levels. Several tumour suppressors and proto-oncogenes have been found either to affect the formation of the mature ribosome or to regulate the activity of proteins known as translation factors. Disruption in one or more of the steps that control protein biosynthesis has been associated with alterations in the cell cycle and regulation of cell growth. Therefore, certain tumour suppressors and proto-oncogenes might regulate malignant progression by altering the protein synthesis machinery. Although many studies have correlated deregulation of protein biosynthesis with cancer, it remains to be established whether this translates directly into an increase in cancer susceptibility, and under what circumstances. Publication Types: Review PMID: 12612653 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 201: Mol Cancer. 2003 Jan 3;2:3. Hepatocarcinogenic potential of the glucocorticoid antagonist RU486 in B6C3F1 mice: effect on apoptosis, expression of oncogenes and the tumor suppressor gene p53. Youssef JA, Badr MZ. University of Missouri-Kansas City, 2411 Holmes Street, Kansas City, MO 64108, USA. badrm@umkc.edu BACKGROUND: Glucocorticoids inhibit hepatocellular proliferation and modulate the expression of oncogenes and tumor suppressor genes via mechanisms involving the glucocorticoid receptor. Glucocorticoids also produce a receptor-mediated inhibitory effect on both basal and hormone-stimulated expression of a newly discovered family of molecules important for shutting off cytokine action. We therefore hypothesized that inhibiting glucocorticoid receptors may disturb hepatocellular growth and apoptosis. Consequently, we investigated the effect of RU486, a potent antagonist of the glucocorticoid receptor, on basal levels of hepatocellular proliferation and apoptosis in male B6C3F1 mice. Furthermore, we evaluated the effect of this compound on cellular genes involved in the regulation of these important processes. RESULTS: Data show that treatment of male B6F3C1 mice with RU486 (2 mg/kg/d, ip) for 7 days dramatically inhibited liver cell proliferation by about 45% and programmed hepatocellular death by approximately 66%. RU 486 also significantly increased hepatic expression of the oncogenes mdm2 and JunB, while reducing that of the tumor suppressor gene p53. CONCLUSION: Exposure to RU486 may ultimately enhance the susceptibility of the liver to cancer risk by diminishing its ability to purge itself of pre-cancerous cells via apoptosis. This effect may be mediated through increases in the hepatic expression of the oncogene mdm2, coupled with decreases in that of the tumor suppressor gene p53. The decrease in hepatocellular proliferation caused by RU 486 may be related to effects other than its anti-glucocorticoid activity. PMID: 12605714 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 202: Arch Toxicol. 2003 Feb;77(2):110-5. Epub 2002 Nov 22. Changes in expression and immunolocalization of protein associated with toxic bile salts-induced apoptosis in rat hepatocytes. Oh SH, Yun KJ, Nan JX, Sohn DH, Lee BH. College of Pharmacy and Medicinal Resources Research Center, Wonkwang University, 344-2 Sinyong-dong, Iksan, Jeonbuk 570-749, Korea. Cholestatic liver injury results from the accumulation of toxic bile salts within the liver. The aim of the present study was to examine the temporal changes in expression and immunolocalization of protein associated with apoptosis in cholestatic rat liver. Rats were anesthetized and cholestasis was induced by double ligation of the common bile duct and sectioning between the ligatures. The animals were euthanized at day 3 and at weeks 1, 2, 4, and 6 after bile duct ligation (BDL). Apoptotic cell death was increased fivefold after 3 days of BDL, decreased over 2 weeks, and remained constant thereafter as has been demonstrated by TUNEL staining. Western blot analysis for Bax, Bcl-2, cytochrome c, and p53 were performed. Results show that total cellular Bax protein was increased 3 days after BDL and decreased over time thereafter. We observed the translocation of Bax to mitochondria and subsequent release of cytochrome c. According to our immunohistochemical data, nuclear p53 increased 3 days after BDL, but cytoplasmic sequestration of p53 was observed after 1 week. The expression of c-Myc was inhibited by 3 days, but increased at later stages following BDL. Bcl-2 was increased over time in BDL rats. Our data suggest toxic bile salts-induced hepatocellular apoptosis is related to differential expression of Bcl-2 family member protein and release of cytochrome c. Cellular localization of p53 plays an important role in apoptotic death of hepatocytes in BDL rats. PMID: 12590363 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 203: Blood. 2003 Jun 1;101(11):4598-606. Epub 2003 Feb 13. The resistance of B-CLL cells to DNA damage-induced apoptosis defined by DNA microarrays. Vallat L, Magdelenat H, Merle-Beral H, Masdehors P, Potocki de Montalk G, Davi F, Kruhoffer M, Sabatier L, Orntoft TF, Delic J. Direction des Sciences du Vivant-Department de Radiopathologie et Radiobiologie, Fontenay aux Roses, France. B-cell chronic lymphoid leukemia (BCLL) is a highly heterogeneous human malignancy, presumably reflecting specific molecular alterations in gene expression and protein activity that are thought to underlie the variable disease outcome. Most B-CLL cell samples undergo apoptotic death in response to DNA damage. However, a clinically distinct aggressive subset of B-CLL is completely resistant in vitro to irradiation-induced apoptosis. We therefore addressed 2 series of microarray analyses on 4 sensitive and 3 resistant B-CLL cell samples and compared their gene expression patterns before and after apoptotic stimuli. Data analysis pointed out 16 genes whose expression varied at least 2-fold specifically in resistant cells. We validated these selected genes by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) on 7 microarray samples and confirmed their altered expression level on 15 additional B-CLL cell samples not included in the microarray analysis. In this manner, in 11 sensitive and 11 resistant B-CLL cell samples tested, 13 genes were found to be specific for all resistant samples: nuclear orphan receptor TR3, major histocompatibility complex (MHC) class II glycoprotein HLA-DQA1, mtmr6, c-myc, c-rel, c-IAP1, mat2A, and fmod were up-regulated, whereas MIP1a/GOS19-1 homolog, stat1, blk, hsp27, and ech1 were down-regulated. In some cases, the expression profile may be dependent on the status of p53. Some of these genes encode general apoptotic factors but also exhibit lymphoid cell specificities that could potentially be linked to the development of lymphoid malignancies (MIP1alpha, blk, TR3, mtmr6). Taken together, our data define new molecular markers specific to resistant B-CLL subsets that might be of clinical relevance. PMID: 12586635 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 204: J Pathol. 2003 Mar;199(3):275-88. Comment in: J Pathol. 2003 Oct;201(2):335-6. Apoptosis and melanoma: molecular mechanisms. Hussein MR, Haemel AK, Wood GS. Department of Dermatology, University of Wisconsin, Madison, Wisconsin 53715, USA. Melanoma cells can undergo self-destruction via programmed cell death, i.e. apoptosis. In these tumours, the molecular components of apoptosis include positive (apoptotic) and negative (anti-apoptotic) regulators. The former include p53, Bid, Noxa, PUMA, Bax, TNF, TRAIL, Fas/FasL, PITSLRE, interferons, and c-KIT/SCF. The latter include Bcl-2, Bcl-X(L), Mcl-1, NF-(K)B, survivin, livin, and ML-IAP. Alternatively, some molecules such as TRAF-2, c-Myc, endothelins, and integrins may have either pro- or anti-apoptotic effects. Some of these molecules are of potential therapeutic use, such as: (1) p53, which influences resistance to chemotherapy; (2) Mcl-1 and Bcl-X(L), which can override apoptosis; (3) TRAIL, which has selective fatal effects on tumour cells; (4) NF-(K)B, which when downregulated sensitizes cells to TRAIL and TNF; (5) the PITSLRE kinases, whose alteration appears to result in Fas resistance; (6) interferons, which sensitize cells to other factors; and (7) survivin and other IAPs that inhibit apoptosis. This review summarizes the state of current knowledge about the key molecular components and mechanisms of apoptosis in melanoma, discusses potential therapeutic ramifications, and provides directions for future research. Copyright 2003 John Wiley & Sons, Ltd. Publication Types: Review Review, Tutorial PMID: 12579529 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 205: Int J Oncol. 2003 Mar;22(3):631-7. Requirement of soluble factors produced by bone marrow stromal cells on the growth of novel established human myeloma cell line. Aikawa S, Hatta Y, Tanaka M, Kaneita Y, Yasukawa K, Sawada U, Horie T, Tsuboi I, Aizawa S. Department of Internal Medicine, Nihon University School of Medicine, Tokyo 173-8610, Japan. The growth of myeloma cells is believed to be mediated by functional interactions between tumor cells and the marrow environment involving the action of several cytokines. We report on the establishment and characterization of a new human myeloma cell line (TAB1) that can be long-term maintained in the presence of conditioned medium of bone marrow stromal cells (BMCM) and a BMCM independent variant, C2-2. Both cell lines have plasma cell morphology and express plasma cell antigens (CD38, PCA-1 and immunoglobulin kappa light chain). In the absence of BMCM, TAB1 cells undergoing apoptosis were observed. Among the adherent molecules tested, these cells expressed VLA-4, ICAM-1 and H-CAM, but not VLA-5, suggesting that these were mostly immature plasmacytes. Introduction with exogenous IL-6 and/or GM-CSF, which were detected in BMCM, partially supported the proliferation of TAB1 cells. Treatment with anti-IL-6 antibody partially inhibited the proliferation of TAB1 cells cultured with BMCM. These findings strongly suggest that TAB1 required at least two or more factors on their growth in vitro; IL-6 was one of the factors necessary for cell growth. Further studies are required to clarify the precise molecules which support TAB1 cell growth in combination with IL-6, however, TAB1 and its variant C2-2 cells may offer an attractive model to unravel novel molecular mechanisms involved in bone marrow stroma-dependent growth of myeloma cells. Publication Types: Case Reports PMID: 12579318 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 206: Zhongguo Zhong Xi Yi Jie He Za Zhi. 2001 Dec;21(12):909-12. [Effect of yiqi jianpi drugs on apoptosis and relevant gene expression in cultured vascular smooth muscle cell] [Article in Chinese] Chai XQ, Wen JK, Han M. Institute of Basic Medical Sciences, Hebei Medical University, Shijiazhuang 050017. OBJECTIVE: To explore the effect of Yiqi Jianpi (YQJP, supplementing Qi and invigorating Spleen) recipe on vascular smooth muscle cells (VSMC) apoptosis and it's mechanisms. METHODS: VSMC apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nicked labeling (TUNEL) analysis, transmission electron microscope (TEM), flow cytometry and DNA agarose electrophoresis. The expression activity of bcl-2, c-myc and p53 genes were determined using Northern blotting. RESULTS: The typical characteristics of apoptotic VSMC was observed following treatment by the YQJP drug serum. The DNA extracted from VSMC revealed a ladder pattern in electrophoresis. Flow cytometric analysis revealed G0/G1 stage cell blocking phenomena, the hypodiploid apoptotic cell increased, displayed typical peak of apoptosis, the rate of cell apoptosis and YQJP serum concentration were in a dose-dependent manner. The result of hybridization showed that 30% of YQJP serum could inhibit apoptotic gene bcl-2 expression, upregulated the level of apoptogenous gene c-myc and p53 mRNA. CONCLUSION: VSMC apoptosis could be induced by YQJP recipe and its mechanism might be through affecting the apoptosis related gene expression activity. PMID: 12575593 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 207: Nat Genet. 2003 Mar;33(3):396-400. Epub 2003 Feb 3. An epi-allelic series of p53 hypomorphs created by stable RNAi produces distinct tumor phenotypes in vivo. Hemann MT, Fridman JS, Zilfou JT, Hernando E, Paddison PJ, Cordon-Cardo C, Hannon GJ, Lowe SW. Cold Spring Harbor Laboratory, Watson School of Biological Sciences, Cold Spring Harbor, New York 11724, USA. The application of RNA interference (RNAi) to mammalian systems has the potential to revolutionize genetics and produce novel therapies. Here we investigate whether RNAi applied to a well-characterized gene can stably suppress gene expression in hematopoietic stem cells and produce detectable phenotypes in mice. Deletion of the Trp53 tumor suppressor gene greatly accelerates Myc-induced lymphomagenesis, resulting in highly disseminated disease. To determine whether RNAi suppression of Trp53 could produce a similar phenotype, we introduced several Trp53 short hairpin RNAs (shRNAs) into hematopoietic stem cells derived from E(mu)-Myc transgenic mice, and monitored tumor onset and overall pathology in lethally irradiated recipients. Different Trp53 shRNAs produced distinct phenotypes in vivo, ranging from benign lymphoid hyperplasias to highly disseminated lymphomas that paralleled Trp53-/- lymphomagenesis in the E(mu)-Myc mouse. In all cases, the severity and type of disease correlated with the extent to which specific shRNAs inhibited p53 activity. Therefore, RNAi can stably suppress gene expression in stem cells and reconstituted organs derived from those cells. In addition, intrinsic differences between individual shRNA expression vectors targeting the same gene can be used to create an 'epi-allelic series' for dissecting gene function in vivo. PMID: 12567186 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 208: Arch Pathol Lab Med. 2003 Feb;127(2):208-12. Expression of p53, c-Myc, or Bcl-6 suggests a poor prognosis in primary central nervous system diffuse large B-cell lymphoma among immunocompetent individuals. Chang CC, Kampalath B, Schultz C, Bunyi-Teopengco E, Logan B, Eshoa C, Dincer AP, Perkins SL. Department of Pathology, Medical College of Wisconsin, Milwaukee 53226, USA. jeffchang@pol.net CONTEXT: Primary central nervous system (CNS) diffuse large B-cell lymphoma (DLBCL) in immunocompetent individuals, although rare, has been rising in incidence. Currently, no reliable prognostic markers are available for these individuals. OBJECTIVE: To study the implications of expression of a panel of oncogenic proteins (Bcl-2, Bcl-6, and c-Myc) and p53 for predicting clinical outcome, particularly overall survival, in immunocompetent individuals with primary CNS DLBCL. DESIGN: Fourteen primary CNS DLBCL cases were retrospectively studied by immunohistochemistry on formalin-fixed, paraffin-embedded sections for the expression of c-Myc, Bcl-2, Bcl-6, and p53. RESULTS: The overall frequencies of expression for p53, c-Myc, Bcl-2, and Bcl-6 in these cases were 29%, 50%, 71%, and 57%, respectively. Cases with expression of p53, c-Myc, or Bcl-6 had a poorer overall survival than those without (Kaplan-Meier survival analysis: 50% cumulative overall survival, 2 months vs 30-60 months, P =.02, log-rank test; 9-16 months vs 21-60 months, P =.03, log-rank test; and 9-16 months vs 21-60 months, P =.16, log-rank test, respectively). The expression of Bcl-2 or proliferation activity by MIB-1 showed no correlation with overall survival. Likewise, the clinical parameters, including age, location of tumors, multiplicity of tumor lesions, and lactase dehydrogenase levels revealed no impact on overall survival. CONCLUSION: Our results suggest that patients with expression of p53, c-Myc, or Bcl-6 have a poorer overall survival than those without. Since traditional prognostic markers in non-CNS DLBCL, such as staging and International Prognostic Index scores, are not applicable to primary CNS DLBCL, evaluation of p53, c-Myc, and Bcl-6 by immunohistochemistry may be warranted as part of prognostic evaluation in immunocompetent patients with primary CNS DLBCL. Further studies are indicated to confirm our observations. PMID: 12562237 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 209: Int J Pediatr Otorhinolaryngol. 2003 Jan;67(1):59-65. Sporadic Burkitt's lymphoma of the head and neck in the pediatric population. Banthia V, Jen A, Kacker A. Department of Otolaryngology-Head and Neck Surgery, New York-Presbyterian, University Hospital of Columbia, New York, NY, USA. Burkitt's lymphoma (BL) is one of the fastest growing malignancies in the pediatric population in the United States. BL is a high-grade B-cell Non-Hodgkin's lymphoma (NHL) which exists in endemic, sporadic, and human immunodeficiency-associated subtypes. The African, or endemic, variant usually involves the maxilla and other facial bones while head and neck manifestations in non-endemic BL are rare. We present three unusual present ations of sporadic BL stemming from Waldeyer's ring and the orbit. The clinical and pathologic features of BL are reviewed. Publication Types: Case Reports PMID: 12560151 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 210: Cancer Cell. 2003 Jan;3(1):37-50. Comment in: Cancer Cell. 2003 Jan;3(1):4-6. The RAG-1/2 endonuclease causes genomic instability and controls CNS complications of lymphoblastic leukemia in p53/Prkdc-deficient mice. Gladdy RA, Taylor MD, Williams CJ, Grandal I, Karaskova J, Squire JA, Rutka JT, Guidos CJ, Danska JS. Program in Developmental Biology, The Hospital for Sick Children and Department of Surgery, University of Toronto, Toronto, Ontario, Canada. Double-strand DNA breaks (DSB) induce chromosomal translocations and gene amplification in cell culture, but mechanisms by which DSB cause genomic instability in vivo are poorly understood. We show that RAG-1/2-induced DSB cause IgH/c-Myc translocations in leukemic pro-B cells from p53/Prkdc-deficient mice. Strikingly, these translocations were complex, clonally heterogeneous and amplified. We observed reiterated IgH/c-Myc fusions on dicentric chromosomes, suggesting that amplification occurred by repeated cycles of bridge, breakage and fusion. Leukemogenesis was not mitigated in RAG-2/p53/Prkdc-deficient mice, but leukemic pro-B cells lacked IgH/c-Myc translocations. Thus, global genomic instability conferred by p53/Prkdc disruption efficiently transforms pro-B cells lacking RAG-1/2-induced DSB. Unexpectedly, RAG-2/p53/Prkdc-deficient mice also developed leptomeningeal leukemia, providing a novel spontaneous model for this frequent complication of human lymphoblastic malignancies. PMID: 12559174 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 211: J Biochem Mol Biol. 2003 Jan 31;36(1):35-42. Use of transgenic and mutant animal models in the study of heterocyclic amine-induced mutagenesis and carcinogenesis. Dashwood RH. Department of Environmental & Molecular Toxicology, and Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA. Rod.Dashwood@oregonstate.edu Heterocyclic amines (HCAs) are potent mutagens generated during the cooking of meat and fish, and several of these compounds produce tumors in conventional experimental animals. During the past 5 years or so, HCAs have been tested in a number of novel in vivo murine models, including the following: lacZ, lacI, cII, c-myc/lacZ, rpsL, and gptDelta. transgenics, XPA-/-, XPC-/-, Msh2+/-, Msh2-/- and p53+/- knock-outs, Apc mutant mice (ApcDelta716, Apc1638N, Apcmin), and A33DeltaNbeta-cat knock-in mice. Several of these models have provided insights into the mutation spectra induced in vivo by HCAs in target and non-target organs for tumorigenesis, as well as demonstrating enhanced susceptibility to HCA-induced tumors and preneoplastic lesions. This review describes several of the more recent reports in which novel animal models were used to examine HCA-induced mutagenesis and carcinogenesis in vivo, including a number of studies which assessed the inhibitory activities of chemopreventive agents such as 1,2-dithiole-3-thione, conjugated linoleic acids, tea, curcumin, chlorophyllin-chitosan, and sulindac. Publication Types: Review Review, Tutorial PMID: 12542973 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 212: Lin Chuang Er Bi Yan Hou Ke Za Zhi. 1999 Sep;13(9):394-6. [Immunohistochemical study of safe resection margin in the surgical treatment of laryngeal carcinoma] [Article in Chinese] Wan B, Dong M, Ma J, Jia J, Ma G, Xie W, Dong M. Department of Otolaryngology, People's Hospital of Henan Province, Zhengzhou 450003. OBJECTIVE: To study safe resection margin of laryngectomy according to the level of protein of gene expression. METHOD: Using citric-LSAB-immunochemical technique, the expressions of ras, c-myc and P53 were studied in different regions of larynx including 30 cases laryngeal carcinoma, border area, adjacent mucosa which was 0.5, 1.0, 1.5, 2.0 cm away from cancer and four normal laryngeal mucosa. RESULT: The results showed that both single expression and co-expression of p21, p62 and p53 increased as tissue progressed in sequence from normal mucosa, 2.0, 1.5, 1.0, 0.5 cm distant mucosa adjacent to carcinoma, border area and carcinoma. A significant different expression in most of them can be seen at regions of 0.5 cm and 1.0 cm distant from the tumor (P < 0.05). CONCLUSION: The tissue 0.5 cm adjacent to the tumor should be regarded as precancerous lesion. It is appropriate to regard 0.5 cm away from tumors as resection margins for surgical treatment of laryngeal carcinoma. PMID: 12541383 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 213: Virchows Arch. 2003 Jan;442(1):1-7. Epub 2002 Nov 12. Molecular biology of laryngeal squamous cell carcinoma. Nadal A, Cardesa A. Department of Anatomia Patologica, Hospital Clinic, Universitat de Barcelona, Villarroel 170, 08036, Spain. Some of the mechanisms involved in neoplastic transformation and progression of laryngeal squamous cell carcinoma (LSCC) are discussed. Although tumor suppressor inactivation of p53 and p16 is common in these tumors (about 50% each), oncogenic activation is less well characterized. Cyclin D1 and epidermal growth factor receptor amplification have been reported in one-third and one-quarter of LSCCs, respectively, both related to advanced stages, whereas c-myc could be amplified in 13% of cases although without associated overexpression. The role of ras in LSCC is, at most, exceptional, and the role of human papillomavirus infection in these neoplasms could have been largely overestimated. The AIS (amplified in squamous carcinoma) gene has been recently proposed as the main oncogenic target in head and neck squamous carcinomas and is a promising line of investigation. This, along with the link that exists between p53 and INK4 suppressor pathways through ARF and MDM-2, and the role of the universal cdk inhibitors (the Cip/Kip family) in these neoplasms deserve further investigation. Not forgotten are the mechanisms leading to cell immortalization and invasive capabilities acquisition, some of which are also briefly described. Publication Types: Review Review, Tutorial PMID: 12536308 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 214: Proc Natl Acad Sci U S A. 2003 Jan 21;100(2):633-8. Epub 2003 Jan 10. CTCF functions as a critical regulator of cell-cycle arrest and death after ligation of the B cell receptor on immature B cells. Qi CF, Martensson A, Mattioli M, Dalla-Favera R, Lobanenkov VV, Morse HC 3rd. Laboratory of Immunopathology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. The WEHI 231 B cell lymphoma is used as a model of self-tolerance by clonal deletion because B cell receptor (BCR) ligation results in apoptosis. Two critical events precede cell death: an early rise and fall in expression of MYC and cell-cycle arrest associated with enhanced expression of p21, p27, and p53. CTCF is a transcription factor identified as a repressor of MYC recently shown to cause cell growth inhibition. The present studies demonstrate that BCR ligation of WEHI 231 as well as of normal immature B cells greatly increased expression of CTCF in association with down-regulation of MYC followed by growth arrest and cell death. Conditional expression of CTCF in WEHI 231 mimicked BCR ligation with activated cells showing repressed expression of MYC, enhanced expression of p27, p21, p53, and p19(ARF), and inhibition of cell growth and induction of apoptosis. In keeping with a central role for CTCF in control of B cell death, conditional expression of a CTCF antisense construct in WEHI 231 resulted in inhibition of p27, p21, p53, and p19(ARF) in association with enhanced expression of MYC. Activation of the endogenous CTCF locus by BCR ligation was also mimicked by three other routes to apoptotic death in WEHI 231: inhibition of the phosphoinositide 3-kinase or mTORFRAP signaling cascades and treatment with transforming growth factor (TGF)-beta. Rapid activation of CTCF by BCR ligation or treatment with TGF-beta was suppressed by ligation of CD40. These results demonstrate that CTCF is a common determinant to different pathways of death signaling in immature B cells. PMID: 12524457 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 215: Ann Med. 2002;34(6):451-69. Induction of apoptosis in cancer: new therapeutic opportunities. Ding HF, Fisher DE. Department of Biochemistry and Molecular Biology, Medical College of Ohio, Toledo, OH, USA. Autonomous cell proliferation is one of the hallmarks of cancer cells, driven by activated growth-promoting oncogenes. However, deregulated activation of these oncogenes also triggers apoptosis via multiple pathways. Among them, the ARF-p53 pathway appears to play a major role in mediating oncogene-induced apoptosis. Consequently, suppression of apoptosis by inactivation of p53 and other tumor suppressors is central to tumor development. These findings have broad implications in understanding cancer genetics and therapy. They help define the roles for oncogenes and tumor suppressor genes in tumorigenesis. Furthermore, the notion that cancer cells often carry specific defects in apoptotic pathways but are inherently sensitive to apoptosis as a result of deregulated proliferation, offers numerous opportunities for manipulating apoptosis in directions of clinical application. Publication Types: Review PMID: 12523501 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 216: J Gastroenterol Hepatol. 2003 Jan;18(1):80-91. Hepatocellular carcinoma in a hepatitis B 'x' transgenic mouse model: A sequential pathological evaluation. Lakhtakia R, Kumar V, Reddi H, Mathur M, Dattagupta S, Panda SK. Department of Pathology, All India Institute of Medical Sciences, Aruna Asaf Ali Marg, New Delhi, India. BACKGROUND: The introduction of transgenic technology has made it possible to study the steps of carcinogenesis and directly establish the link between viral subgenomic fragments and specific types of cancer. Research directed at hepatitis B virus (HBV)-related carcinogenesis has benefited from this technology. We present a detailed pathological evaluation of the sequential steps of hepatocarcinogenesis in a hepatitis B 'x' (HBx) transgenic mouse model. In this model, the transgene incorporates the region encoding amino acids 58-154 of the HBV X protein and the murine c-myc gene. This model demonstrated changes in the liver from birth with foci of multicentric dysplasia evolving into nodules and overt hepatocellular carcinoma between 20 and 28 weeks. METHODS AND RESULTS: The hepatocytes were mitotically active and showed increased proliferative capacity soon after birth, with exponential increase thereafter. This was accompanied by a high rate of apoptosis, which later declined as the tumors developed. Other functional and immunophenotypic characteristics included a high c-myc expression in the neoplastic lesions, no alteration in p53 expression, and no alteration in the expression of hepatic enzymes except for diffuse expression of succinic dehydrogenase. CONCLUSION: The entire process illustrates the disturbances of cell growth and death because of the collaborative influence of HBx and c-myc genes that result in the development of hepatocellular carcinoma after a prolonged latent period. Copyright 2003 Blackwell Publishing Asia Pty Ltd PMID: 12519229 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 217: Lancet Oncol. 2003 Jan;4(1):22-9. Emerging pathways in the development of AIDS-related lymphomas. Carbone A. Centro di Riferimento Oncologico-IRCCS, Aviano, Italy. acarbone@cro.itc The clinicopathological range of AIDS-related non-Hodgkin lymphomas (NHLs) includes systemic lymphomas, primary central-nervous-system lymphomas, primary effusion lymphoma, and plasmablastic lymphoma of the oral cavity. Most AIDS-related NHLs belong to one of three categories of high-grade B-cell lymphomas: Burkitt's lymphoma, centroblastic lymphoma, and immunoblastic lymphoma. The pathological heterogeneity of AIDS-related NHL reflects the heterogeneity of their associated molecular lesions. In AIDS-related Burkitt's lymphoma, the molecular lesions involve activation of c-MYC, inactivation of p53, and infection with Epstein-Barr virus (EBV). AIDS-related immunoblastic lymphomas infected with EBV are characterised by frequent expression of latent membrane protein 1-an EBV oncoprotein. The biological heterogeneity of AIDS-related NHLs is highlighted by their histogenetic differences; AIDS-related NHLs are related to distinct B-cell subgroups (eg, germinal-centre or post-germinal-centre B cells). The phenotypic pattern of AIDS-related Burkitt's lymphomas and systemic AIDS-related centroblastic lymphomas closely reflects that of B cells in germinal centres. Conversely, the phenotype of AIDS-related immunoblastic lymphomas and AIDS-related primary effusion lymphomas reflects post-germinal-centre B cells in all cases. Despite their clinicopathological, genetic, and phenotypic heterogeneity, most lymphomas in patients with AIDS carry somatic mutations of immunoglobulin and BCL-6 genes. However, the somatic hypermutation mechanism functions aberrantly in a significant proportion of AIDS-related NHLs, causing the mutation of many genes, and possibly favouring chromosomal translocation, which may be a powerful contributor to malignant transformation. New molecular and virological evidence of such pathways and a greater knowledge of other biological features of AIDS-related NHLs may lead to new targets for pathogenetically and biologically oriented therapies. Publication Types: Review PMID: 12517536 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 218: Apoptosis. 2003 Jan;8(1):11-8. Roles of the stress-induced gene IEX-1 in regulation of cell death and oncogenesis. Wu MX. Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, MA 02118, USA. mxwu@bu.edu In response to changes in the external environment cells must initiate a coordinated program of gene expression for them to adapt. IEX-1 (immediate early response gene X-1) is precisely regulated by multiple transcription factors among which p53, NF-kappaB/rel, Sp1 and c-Myc play central roles, to ensure rapid and transient expression of IEX-1 in cells under a variety of stress conditions. Overexpression of IEX-1 renders some cells sensitive to apoptosis and accelerates cell cycle progression, but reduces proliferation of other cells, whereas disruption of IEX-1 expression is associated with decreases in both apoptosis and cell cycle progression. In sharp contrast to in vitro studies, in vivo constitutive expression of IEX-1 prevents activated T cells but not B cells from apoptosis, as shown using IEX-1-transgenic mice that target IEX-1 expression specifically to lymphocytes driven by the Emu enhancer. The animals developed a lupus-like disease and subsequently a high incidence of T cell lymphomas when they aged, due to insufficient apoptosis of T cells. These varied effects of IEX-1 on cell death and cell cycle progression in a cell-context dependent fashion implicate that IEX-1 is involved in more than one signaling pathway, understanding of which will certainly improve our knowledge with respect to cancer biology, cell death and cell cycle regulation. Publication Types: Review Review, Tutorial PMID: 12510147 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 219: Genet Med. 2002 Nov-Dec;4(6):439-43. Asynchronous replication of biallelically expressed loci: a new phenomenon in Turner syndrome. Reish O, Gal R, Gaber E, Sher C, Bistritzer T, Amiel A. Genetic Institute, Assaf Harofeh Medical Center, Zerifin, Israel. PURPOSE: Transcriptional activity of genes is related to their replication timing; alleles showing the common biallelic mode of expression replicate synchronously, whereas those with a monoallelic mode of expression replicate asynchronously. Here the level of synchronization in replication timing of alleles was determined in subjects with Turner syndrome. METHODS: Fluorescence in situ hybridization was used for three loci not linked to X chromosome, in lymphocytes derived from 12 controls, 3 individuals with Turner, and 4 with mosaic Turner syndrome. RESULTS: In cells derived from controls, each pair of alleles replicated synchronously; yet these same alleles replicated asynchronously in cells monosomic for X chromosome derived from Turner and mosaic Turner patients. When the level of 45,X was low in the mosaic samples, the replication pattern of the 46,XX cells was normal. However, in samples with a high level of mosaicism, a significantly increased asynchronous replication was detected in the 46,XX cells. CONCLUSION: An altered temporal replication control in Turner syndrome affecting the aneuploid and euploid cells is shown. This alteration may potentially be involved in the determination of the syndrome. PMID: 12509715 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 220: World J Gastroenterol. 2003 Jan;9(1):54-8. Helicobacter pylori infection generated gastric cancer through p53-Rb tumor-suppressor system mutation and telomerase reactivation. Lan J, Xiong YY, Lin YX, Wang BC, Gong LL, Xu HS, Guo GS. Department of Pathology, Zhongnan Hospital, Wuhan University,Wuhan city 430071, Hubei Province, China. lanjing_2002@hotmail.com AIM: To investigate the relationship between Helicobacter pylori (H.pylori) infection and the expressions of the p53, Rb, c-myc, bcl-2 and hTERT mRNA in a series of diseases from chronic gastritis (CG), intestinal metaplasia type I or II(IMI-II), intestinal metaplasia type III (IMIII), mild or modest dysplasia (DysI-II), severe dysplasia (DysIII) to gastric cancer(GC) and to elucidate the mechanism of gastric carcinogenesis relating to H.pylori infection. METHODS: 272 cases between 1998 and 2001 were available for the study including 42 cases of CG, 46 cases of IMI-II, 25 cases of IMIII, 48 cases of DysI-II, 27 cases of DysIII, 84 cases of GC. H.pylori infection and the expressions of p53, Rb, c-myc, bcl-2 were detected by means of streptavidin-peroxidase (SP) immunohistochemical method. HTERT mRNA was detected by in situ hybridization (ISH). RESULTS: The expressions of p53, Rb, c-myc, hTERT mRNA and bcl-2 were higher in the GC than in CG, IM, Dys. The expression of c-myc was higher in IMIII with H.pylori infection (10/16) than that without infection (1/9) and the positive rate in DysI-II and DysIII with H.pylori infection was 18/30 and 13/17, respectively, higher than that without infection (4/18 and 3/10, respectively). In our experiment mutated p53 had no association with H.pylori infection, the expression of Rb was associated with H.pylori infection in GC, but the p53-Rb tumor-suppressor system abnormal in DysI-II cases, DysIII and GC cases with H.pylori infection was 21/30, 15/17 and 48/48 respectively, higher than non-infection groups (4/18, 3/10, 28/36). Furthermore the level of hTERT mRNA in GC with H.pylori infection (47/48) was higher than that without infection (30/36), however the relationship between bcl-2 and H.pylori was only in IMIII. C-myc had a close association with hTERT mRNA in DysIII and GC (P=0.0 253,0.0 305 respectively). CONCLUSION: In the gastric carcinogenesis, H.pylori might cause the severe imbalance of proliferation and apoptosis in the precancerous lesions (IMIII and GysIII) first, leading to p53-Rb tumor-suppressor system mutation and telomerase reactivation, and finally causes gastric cancer. PMID: 12508351 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 221: J Surg Oncol. 2003 Jan;82(1):34-50. Prognostic significance of biomarkers in squamous cell carcinoma of the tongue: multivariate analysis. Vora HH, Shah NG, Patel DD, Trivedi TI, Chikhlikar PR. Department of Cancer Biology, Division of Molecular Endocrinology, Gujarat Cancer and Research Institute, NCH Compound, Asarwa, Ahmedabad, India. BACKGROUND AND OBJECTIVES: Expression of a panel of biomarkers, such as p53, Bcl-2, Cyclin D1, c-myc, p21ras, c-erb B2, cytokeratin-19 (CK-19), and factor VIII-related antigen (FVIII-RA), was studied together in anterior tongue tumors from the oral cavity and in posterior tongue tumors from the oropharynx of patients with early- and locally advanced-stage disease, to evaluate their prognostic value. METHODS: The expression of the above-mentioned biomarkers was studied by immunohistochemical localization. RESULTS: In this study, 18%, 26%, 62%, 75%, 73%, 50%, and 29% of the tumors exhibited p53, Bcl-2, Cyclin D1, c-myc, p21ras, c-erb B2, and CK-19 expression, respectively. Twenty percent of the tumors had a microvessel count of >0.0. The expression of these biomarkers was also correlated with clinicopathologic parameters. In early-stage patients with a tobacco habit, who showed borderline significance for relapse-free survival by Kaplan-Meier survival analysis, this turned out to be significant, with the general linear model univariate survival analysis. In the total group, disease stage emerged as the most significant prognostic factor, followed by c-myc, when Cox forward stepwise regression and general linear model multivariate survival analysis were performed. However, Cyclin D1, which was significant by Cox forward stepwise regression analysis, lost its significance by general linear model multivariate analysis. In patients with early-stage disease, MVC, which was a significant predictor of disease relapse by Cox forward stepwise regression analysis, lost its significance by general linear model analysis because of small number of patients. In patients with locally advanced tongue cancer, multivariate survival analysis of individual biomarkers by both Cox forward stepwise regression and general linear model analysis indicated c-myc expression to be strongly indicative of poor prognosis. However, multivariate analysis of individual markers along with a combination of markers showed that only by Cox forward stepwise regression analysis did the combined expression of markers c-myc, Cyclin D1, and p21ras emerge as a significant independent prognosticator. CONCLUSIONS: Overall stage emerged as the most significant prognostic indicator of disease outcome. Tobacco habit also affected relapse-free survival in patients with early-stage disease. However, immunostaining of c-myc in the tumors of locally advanced-stage tongue cancer patients might be a potential adjunct to clinical stage in the pathologic evaluation of tongue specimens. Copyright 2002 Wiley-Liss, Inc. PMID: 12501167 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 222: Ai Zheng. 2002 Jan;21(1):63-7. [Relationship between expression of c-myc and p53 in liposarcoma] [Article in Chinese] Wang YL, Qiu JS, Xiong M. Department of Pathology, Chongqing University of Medical Sciences, Chongqing 400016, P. R. China. BACKGROUND & OBJECTIVE: The relationship between liposarcoma and gene c-myc and p53 is not clear. There are also different reports on p53 mutation in liposarcoma. This study was designed to investigate the relationship between the expression of c-myc and p53 genes and liopsarcomas. We hope to better understand the role of the c-myc and p53 genes in molecular biology. METHODS: Immunohistochemical labelled streptavidin-biotin (LSAB) method, single strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP), and DNA sequencing were used. RESULTS: 38.09% (16/42) liposarcoma samples detected were immunohistochemically c-myc protein positive. p53 protein was detected in 52 liposarcomas with the positive staining rate of 48.08% (25/52). In different subtypes of liposarcomas, the positive staining rates of c-myc and p53 gene proteins were much lower in well-differentiated liposarcomas than in the poorly differentiated liposarcomas. There was a positive correlation between c-myc and p53 expression in liposarcoma. There was no statistical significance for the different positive staining rate of c-myc and p53 protein in the primary and the recurrent liposarcoma. Abnomality in the single-stranded DNA pattern was determined by PCR-SSCP analysis in 2 samples (pleomophic liposarcomas). Missense mutation in exon 8 of codon 268 of p53 gene (AAC-->ATC) were detected by DNA sequencing. Another heterozygotic cosense mutation may exist at exon 6 of codon 221 of p53 gene (GAG-->GAA). CONCLUSIONS: The c-myc and p53 protein are associated with the development, differentiation, and malignancy of liposarcoma, but not with the recurrence of liposarcoma. Detecting the level of c-myc and p53 protein expression may be valuable in evaluating the level of differentiation and malignancy of liposarcoma. c-myc and p53 play synergic roles in the cooperation of development of liposarcoma. There appear the point mutation on exon 8, 6 of p53 gene. PMID: 12500400 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 223: In Vivo. 2002 Sep-Oct;16(5):307-10. Effect of cisplatin treatment on early activation of oncogenes in vivo. Nemeth A, Gyongyi Z, Nadasi E, Ember A, Olasz L, Nyarady Z, Skapinyecz J, Ember I. Departments of Public Health and Preventive Medicine, University of Pecs H-7643 Pecs Szigeti u. 12, Hungary. The aim of the study was to monitor the early effect of cytostatics containing platinum on oncogenes in inbred CBA/Ca mice. In human head-neck tumors after treatment with the Cisplatin supplemented BVM (Bleomycin, Vincristine, Methotrexate) protocol, further surgeries are often necessary due to regional recurrence. Body weight equivalent amounts of human dose of Cisplatin were administered intraperitoneally to 6-8-week-old, inbred, female CBA/Ca mice. Twenty four 48 and 72 hours after the treatment RNA was isolated from the target organs and the quantitative expression of c-myc, Ha-ras and p53 genes was examined by dot-blotting in potential target tissues. Significant overexpression of Ha-ras and p53 genes was measured in the bone marrow. Regarding the expression of Ha-ras gene, a significant increase was also found in the lymph nodes after 48 hours. The p53 expression in the lungs was down-regulated compared to the control group. In the "short-term" in vivo test, 24-hour examination of gene expression and amplification is suitable for detecting the early effects of carcinogenetic exposure. Cisplatin-induced gene expression alterations call attention to its possible role in the development of regional recurrence in patients treated with cisplatin-containing regimens. Publication Types: Case Reports PMID: 12494868 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 224: J Pharmacol Exp Ther. 2003 Jan;304(1):37-47. c-myc down-regulation induces apoptosis in human cancer cell lines exposed to RPR-115135 (C31H29NO4), a non-peptidomimetic farnesyltransferase inhibitor. Russo P, Arzani D, Trombino S, Falugi C. Laboratory of Experimental Oncology, Molecular Pathology Section, National Institute for Research on Cancer, Genoa, Italy. patrizia.russo@istge.it A therapeutic strategy that relies on the use of c-myc antisense in combination with a farnesyltransferase inhibitor, RPR-115135 (C31H29NO4), was studied in human cancer cell lines carrying different mutations (Ras, p53, myc amplification). Cell proliferation was strongly inhibited by the combination and was observed when c-myc oligo (at a concentration that down-regulates c-myc expression) was followed by RPR-115135. Cell cycle analysis demonstrated an accumulation in G0-G1 phase and a tendency to apoptosis (not detectable in cells treated with a single agent). Morphological examination and DNA fragmentation assays (filter binding and enzyme-linked immunosorbent assay DNA fragmentation) confirmed the induction of apoptosis. Apoptosis was not p53- and/or p21(waf-1)-dependent, and the key effector was caspase activation. The combination induced Bax expression and Bcl-2 inhibition. Down-regulation of c-myc amplification carried out a specific role exclusively when Ras was mutated. Exposure of human proliferating lymphocytes to combination did not result in cytotoxicity, suggesting that mechanisms regulating c-myc gene expression during normal T cell proliferation might not be involved. Because of the high percentage of human tumors overexpressing c-myc mRNA and/or protein and, simultaneously, harboring oncogenic Ras mutants (i.e., colon cancers), interrupting the myc- and Ras-signaling pathway would be one of the major focuses on therapy of these types of tumors. PMID: 12490573 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 225: Leuk Res. 2003 Jan;27(1):73-8. Antisense p53 transduction leads to overexpression of bcl-2 and dexamethasone resistance in multiple myeloma. Iyer R, Ding L, Batchu RB, Naugler S, Shammas MA, Munshi NC. Myeloma and Transplantation Research Center, University of Arkansas for Medical Sciences and Central Arkansas VA Medical Center, Little Rock, AR 72205, USA. Multiple myeloma is a malignant proliferation of plasma cells which fail to undergo apoptosis. To understand events associated with lack of apoptosis in these cells, we studied effect of antisense p53 gene transduction in a multiple myeloma cell line, ARH77. Adeno-associated virus was used as a vector to introduce p53 cDNA in an antisense orientation driven by a herpes virus thymidine kinase promoter. We observed, that an antisense p53 (p53as) transduced cell line showed marked reduction in p53 mRNA and protein expression and increased growth when compared to the control cell lines transduced with neomycin-resistance gene or untransduced cells. There was a concomitant up-regulation of bcl-2 expression by over five-fold in p53as-transduced cells compared with controls; while there was no significant change in expression of c-myc and IL-6, genes implicated in myeloma growth. We measured apoptosis in the transduced cells by DNA end-labeling reaction which revealed decrease in apoptosis from 15.6% in control cells to 1.6% in p53as-transduced cells. Additionally, the p53as cells over expressing bcl-2 also showed resistance to killing by dexamethasone. In summary, our data demonstrates that loss of p53 function leads to myeloma cell progression and resistant phenotype through bcl-2-related mechanisms. PMID: 12479855 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 226: Cancer Cell. 2002 Nov;2(5):351-2. Switching from life to death: the Miz-ing link between Myc and p53. Vousden KH. Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Galsgow G61 1BD, UK. k.vousden@beatson.gla.ac.uk Cells can respond to the activation of the tumor suppressor protein p53 by undergoing cell cycle arrest or apoptosis, and Myc has now been shown to help switch the response to apoptosis by repressing the expression of p21(CIP1), a cyclin-dependent kinase inhibitor with antiapoptotic activity. Publication Types: Review Review, Tutorial PMID: 12450789 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 227: J Asian Nat Prod Res. 2002 Dec;4(4):271-80. Inhibition of tumor growth by S-3-1, a synthetic intermediate of salvianolic acid A. Li HY, Li Y, Yan CH, Li LN, Chen XG. Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China. Salvianolic acid A (1) is one of the active components from Salvia miltiorrhiza, which was found to suppress the growth of mouse tumors. S-3-1 (a 2-allyl-3,4-dihydroxybenzaldehyde, 2) is a synthetic intermediate of a salvianolic acid A derivative with strong inhibitory effects on the growth of cancer cells in vitro. The inhibitory effects of 2 on tumor growth and its molecular targets were studied. 2 significantly suppressed the growth of mouse Lewis lung carcinoma, S180 sarcoma and H22 hepatic carcinoma in a dose-dependent manner. With a simple scrape-loading dye transfer method, 20 microg/ml of 2 was found to significantly enhance gap junction intercellular communication (GJIC) in human pancreatic adenocarcinoma PaCa Cells, human lung epithelial carcinoma W1-38 cells and human lung adenocarcinoma A549 cells, but 2 had no marked effect on GJIC in human colon cancer CACO2 cells. With Northern blot analysis, 2 was found to inhibit the expression of c-myc gene in A549 cells and have no marked effect on H-ras oncogene expression, and increase the cellular P53 mRNA contents, though it did not affect the expression of RB tumor suppressor gene. 2 also suppressed the P46 (JNK/SAPK) expression in A549 cells. Western blot analysis was applied to visualize the P21ras protein. Results shows that 2 at concentrations ranging from 10 to 20 microg/ml decreases the contents of the membranous P21ras and total P21ras and increases the contents of cytosolic P21ras protein in a time-dependent manner. However, 2 had no significant effects on farnesyl protein transferase activities at the concentrations that could efficiently decrease the membranous P21ras content. This suggested that 2 might suppress tumor growth partly through enhancement of GJIC and reversion of the transformed phenotypes. The other mechanisms may be that 2 can suppress the overexpression of c-myc oncogene, inhibit the function of Ras oncoprotein, increase the expression of P53 tumor suppressor gene and interrupt P46-associated mitogen-activated pathway other than farnesylation of Ras protein. PMID: 12450255 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 228: Virchows Arch. 2002 Nov;441(5):449-55. Epub 2002 Jul 24. Expression of c-erbB2, p53, Bcl-2, Bax, c-myc and Ki-67 in apocrine metaplasia and apocrine change within sclerosing adenosis of the breast. Selim AG, El-Ayat G, Wells CA. Department of Histopathology, St. Bartholomew's Hospital, Royal London School of Medicine and Dentistry, Queen Mary and Westfield College, University of London, West Smithfield, London EC1A 7BE, UK. aaselim@doctors.org.uk Molecular evidence has recently suggested a number of different pathways leading to the development of ductal carcinoma of the breast. The links between atypical ductal hyperplasia and low-grade ductal carcinoma in situ and lobular neoplasia and lobular carcinoma are well known pathologically, but high-grade in situ and invasive carcinomas appear to have a different biological oncogenetic pathway. Morphologically there is a similarity between apocrine cells and some cases of high-grade ductal carcinoma. In order to investigate this possibility a number of different biological markers known to occur in high-grade breast carcinomas were assessed in both apocrine metaplasia (APM) and a putative premalignant lesion called apocrine change within sclerosing adenosis (AA). In 64 cases of APM and 18 cases of AA we examined for expression of c-erbB2, p53, Bcl-2, Bax, c-myc and Ki-67 proteins using immunocytochemistry. c-erbB2 expression was seen in 55.6% of AA cases and in 10.9% of APM cases. p53 expression was detected in 27.8% of AA cases but only 1.6% of APM cases. All cases of AA and APM were negative for the anti-apoptotic protein Bcl-2, but all the APM and 33.3% of AA cases showed cytoplasmic positivity for Bax, a pro-apoptotic protein. All the cases of AA and APM were positive for c-myc oncoprotein, however, the mean percentage of nuclear positivity was 50% in AA and 37% in cases of APM cases. The mean percentage positivity for Ki-67, a proliferation associated antigen, was 3.6% in AA and 1.3% in APM. The results indicate that a subset of breast lesions containing APM epithelium show abnormal oncoprotein and apoptosis-related protein expression and have a higher proliferation rate. PMID: 12447674 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 229: Isr Med Assoc J. 2002 Sep;4(9):702-5. Asynchronous replication of alleles in genomes carrying a microdeletion. Amiel A, Reish O, Gaber E, Masterman R, Tohami T, Fejgin MD. Genetic Institute, Meir General Hospital, Kfar Saba, Israel. alizaamiel@hotmail.com BACKGROUND: While most allelic pairs of DNA replicate synchronously during the S phase of the cell cycle, some genes normally replicate asynchronously, i.e., genes on the X chromosome and imprinted genes. The replication control mechanism is unknown but was shown to be impaired in malignancies and chromosomal trisomies where replication pattern becomes asynchronous. OBJECTIVES: To determine the level of asynchronization in replication timing of cells from patients with microdeleted genomes. METHODS: We applied monocolor fluorescent in situ hybridization with different probes on leukocytes from microdeleted genomes. RESULTS: All samples derived from the microdeleted genomes showed significantly higher levels of an asynchronized pattern compared to normal individuals. CONCLUSIONS: Even a "small" genetic imbalance (microdeletion) can interfere with gene replication and cell cycle progression, as previously shown in full trisomies. PMID: 12440235 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 230: Acta Pharmacol Sin. 2002 Nov;23(11):997-1001. Effect of isoverbascoside, a phenylpropanoid glycoside antioxidant, on proliferation and differentiation of human gastric cancer cell. Chen RC, Su JH, Yang SM, Li J, Wang TJ, Zhou H. Cancer Research Center, School of Life Sciences, Xiamen University, Xiamen 361005, China. chenruichuan@yahoo.com AIM: To investigate the effects of phenylpropanoid glycoside antioxidant isoverbascoside on cell proliferation and differentiation of human gastric cancer cell line MGC 803. METHODS: MGC 803 cells were treated with isoverbascoside. Its effects on cell proliferation, tumorigenicity, enzymatic activities, cell cycles, and gene expression were respectively evaluated with cell counting, tumor formation assay, enzymatic assay, flow cytometer analysis, and Western blotting, with Me2SO as positive control. RESULTS: Isoverbascoside could markedly inhibit cell proliferation in dose- and time-dependent manner. Isoverbascoside 20 micromol/L strikingly suppressed cell tumorigenicity, activities of alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), and caused G0/G1 arrest. The expression of G1 S checkpoint related proteins, p53, p21/WAF1, and p16/INK4, were up-regulated after MGC 803 cells were treated with isoverbascoside 20 micromol/L for 4-8 h. Contrarily, the expression of C-myc protein was suppressed after 8 h treatment. CONCLUSION: Isoverbascoside inhibited cell proliferation, reversed cell malignant phenotypic characteristics, and consequently caused differentiation in MGC 803 cells. These effects might be associated with its activities of causing G0/G1 arrest and regulating the expression of cell cycle related proteins. PMID: 12421475 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 231: Zhonghua Zhong Liu Za Zhi. 2002 Jul;24(4):348-52. Anticancer activities of curcumin on human Burkitt's lymphoma. Wu Y, Chen Y, Xu J, Lu L. Fujian Institute of Hematology, Union Hospital, Fujian Medical University, Fuzhou 350001, China. OBJECTIVE: To study the anticancer activities of curcumin on human Burkitt's lymphoma and their molecular mechanism. METHODS: The effect of curcumin on the growth of CA46 cells and apoptosis were studied through Trypan blue exclusion, MTT assay, cell cycle, DNA fragmentation analysis and detection of TdT-mediated dUTP nick end labeling (TUNEL). The effect of curcumin on the expression of c-myc, bcl-2, mutant-type p53 and Fas protein and mRNA was studied by flow cytometry (FCM) and reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: 1. Curcumin inhibited proliferation of CA46 cells in a time- and dose-dependent manner, 2. CA46 cells treated with curcumin showed G(0)/G(1) or G(2)/M phase increase and S phase decrease, 3. CA46 cells apoptosis induced by curcumin was confirmed by DNA fragmentation and TUNEL and 4. The expression of c-myc, bcl-2, mutant-type p53 protein and mRNA was decreased sharply in CA46 cells treated with curcumin, while Fas protein and mRNA was increased. CONCLUSION: Curcumin is able to inhibit the proliferation of CA46 cells and induce the cell apoptosis by down-regulating the expression of c-myc, bcl-2, mutant-type p53 and up-regulating the expression of Fas. PMID: 12408761 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 232: Am J Med Genet. 2002 Oct 30;115(3):183-8. Cytogenetics and molecular genetics of lung cancer. Mitsuuchi Y, Testa JR. Fox Chase Cancer Center in Philadelphia, Pennsylvania 19111, USA. The development and progression of lung cancer is a multistep process characterized by the accumulation of numerous genetic and epigenetic alterations, some of which occur early in the course of disease. In this review, we summarize cytogenetic imbalances and molecular genetic/epigenetic changes seen in human small-cell and non-small-cell lung cancer. Alterations of tumor suppressor genes and oncogenes leading to perturbations of key cell-regulatory and growth-control pathways are highlighted. The translational implications of molecular biomarkers for risk assessment, early detection, and monitoring of chemoprevention trials are discussed. Copyright 2002 Wiley-Liss, Inc. Publication Types: Review Review, Tutorial PMID: 12407699 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 233: Cancer Lett. 2002 Dec 15;188(1-2):153-62. Unsaturated fatty acids bind Myc-Max transcription factor and inhibit Myc-Max-DNA complex formation. Chung S, Park S, Yang CH. School of Chemistry and Molecular Engineering, Seoul National University, 151-742, Seoul, South Korea. Oncoprotein Myc, hetero-dimerized with Max through a b/HLH/Zip region, is a transcription factor that governs important cellular processes such as cell cycle entry, proliferation and differentiation. We found that linoleic acid, isolated from Pollen Typhae, and other unsaturated fatty acids have strong inhibitory effects on the binding of Myc-Max heterodimer to an E-box DNA site (CA(C/T)GTG). The interaction of a fatty acid with a protein dimer, not with DNA, is assumed to block the entire Myc-Max-DNA complex formation. Unsaturated fatty acids also showed cytotoxicity against a SNU16 human stomach cancer cell line and conjugated linoleic acid suppressed mRNA expression of several myc-target genes; ornithine decarboxylase, p53, cdc25a in the SNU16 cells. PMID: 12406560 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 234: J Cell Biochem. 2002;87(3):266-78. Hydrostatic pressure induces apoptosis in human chondrocytes from osteoarthritic cartilage through up-regulation of tumor necrosis factor-alpha, inducible nitric oxide synthase, p53, c-myc, and bax-alpha, and suppression of bcl-2. Islam N, Haqqi TM, Jepsen KJ, Kraay M, Welter JF, Goldberg VM, Malemud CJ. Department of Orthopaedics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4946, USA. Hydrostatic pressure (HP) is thought to increase within cartilage extracellular matrix as a consequence of fluid flow inhibition. The biosynthetic response of human articular chondrocytes to HP in vitro varies with the load magnitude, load frequency, as well as duration of loading. We found that continuous cyclic HP (5 MegaPascals (MPa) for 4 h; 1 Hz frequency) induced apoptosis in human chondrocytes derived from osteoarthritic cartilage in vitro as evidenced by reduced chondrocyte viability which was independent of initial cell densities ranging from 8.1 x 10(4) to 1.3 x 10(6) cells ml(-1). HP resulted in internucleosomal DNA fragmentation, activation of caspase-3, and cleavage of poly-ADP-ribose polymerase (PARP). At the molecular level, induction of apoptosis by HP was characterized by up-regulation of p53, c-myc, and bax-alpha after 4 h with concomitant down-regulation of bcl-2 after 2 h at 5 MPa as measured by RT-PCR. In contrast, beta-actin expression was unchanged. Real-time quantitative RT-PCR confirmed a HP-induced (5 MPa) 1.3-2.6 log-fold decrease in bcl-2 mRNA copy number after 2 and 4 h, respectively, and a significant increase (1.9-2.5 log-fold) in tumor necrosis factor-alpha (TNF-alpha) and inducible nitric oxide synthase (iNOS) mRNA copy number after 2 and 4 h, respectively. The up-regulation of p53 and c-myc, and the down-regulation of bcl-2 caused by HP were confirmed at the protein level by Western blotting. These results indicated that HP is a strong inducer of apoptosis in osteoarthritic human chondrocytes in vitro. Copyright 2002 Wiley-Liss, Inc. PMID: 12397608 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 235: Blood. 2003 Feb 15;101(4):1220-35. Epub 2002 Sep 12. Cell cycle deregulation in B-cell lymphomas. Sanchez-Beato M, Sanchez-Aguilera A, Piris MA. Lymphoma Group, Molecular Pathology Program, Centro Nacional de Investigaciones Oncologicas (CNIO), Madrid, Spain. Disruption of the physiologic balance between cell proliferation and death is a universal feature of all cancers. In general terms, human B-cell lymphomas can be subdivided into 2 main groups, low- and high-growth fraction lymphomas, according to the mechanisms through which this imbalance is achieved. Most types of low-growth fraction lymphomas are initiated by molecular events resulting in the inhibition of apoptosis, such as translocations affecting BCL2, in follicular lymphoma, or BCL10 and API2/MLT1, in mucosa-associated lymphoid tissue (MALT) lymphomas. This results in cell accumulation as a consequence of prolonged cell survival. In contrast, high-growth fraction lymphomas are characterized by an enhanced proliferative activity, as a result of the deregulation of oncogenes with cell cycle regulatory functions, such as BCL6, in large B-cell lymphoma, or c-myc, in Burkitt lymphoma. Low- and high-growth fraction lymphomas are both able to accumulate other alterations in cell cycle regulation, most frequently involving tumor suppressor genes such as p16(INK4a), p53, and p27(KIP1). As a consequence, these tumors behave as highly aggressive lymphomas. The simultaneous inactivation of several of these regulators confers increased aggressivity and proliferative advantage to tumoral cells. In this review we discuss our current knowledge of the alterations in each of these pathways, with special emphasis on the deregulation of cell cycle progression, in an attempt to integrate the available information within a global model that describes the contribution of these molecular changes to the genesis and progression of B-cell lymphomas. Publication Types: Review Review, Tutorial PMID: 12393483 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 236: Mol Cell Biol. 2002 Nov;22(22):7831-41. Activation of Akt/protein kinase B overcomes a G(2)/m cell cycle checkpoint induced by DNA damage. Kandel ES, Skeen J, Majewski N, Di Cristofano A, Pandolfi PP, Feliciano CS, Gartel A, Hay N. Department of Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60607, USA. Activation of Akt, or protein kinase B, is frequently observed in human cancers. Here we report that Akt activation via overexpression of a constitutively active form or via the loss of PTEN can overcome a G(2)/M cell cycle checkpoint that is induced by DNA damage. Activated Akt also alleviates the reduction in CDC2 activity and mitotic index upon exposure to DNA damage. In addition, we found that PTEN null embryonic stem (ES) cells transit faster from the G(2)/M to the G(1) phase of the cell cycle when compared to wild-type ES cells and that inhibition of phosphoinositol-3-kinase (PI3K) in HEK293 cells elicits G(2) arrest that is alleviated by activated Akt. Furthermore, the transition from the G(2)/M to the G(1) phase of the cell cycle in Akt1 null mouse embryo fibroblasts (MEFs) is attenuated when compared to that of wild-type MEFs. These results indicate that the PI3K/PTEN/Akt pathway plays a role in the regulation of G(2)/M transition. Thus, cells expressing activated Akt continue to divide, without being eliminated by apoptosis, in the presence of continuous exposure to mutagen and accumulate mutations, as measured by inactivation of an exogenously expressed herpes simplex virus thymidine kinase (HSV-tk) gene. This phenotype is independent of p53 status and cannot be reproduced by overexpression of Bcl-2 or Myc and Bcl-2 but seems to counteract a cell cycle checkpoint mediated by DNA mismatch repair (MMR). Accordingly, restoration of the G(2)/M cell cycle checkpoint and apoptosis in MMR-deficient cells, through reintroduction of the missing component of MMR, is alleviated by activated Akt. We suggest that this new activity of Akt in conjunction with its antiapoptotic activity may contribute to genetic instability and could explain its frequent activation in human cancers. PMID: 12391152 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 237: Oncogene. 2002 Oct 24;21(49):7593-7. Increased incidence of ERBB2 overexpression and TP53 mutation in inflammatory breast cancer. Turpin E, Bieche I, Bertheau P, Plassa LF, Lerebours F, de Roquancourt A, Olivi M, Espie M, Marty M, Lidereau R, Vidaud M, de The H. Service de Biochimie B and CNRS UPR9051, Hopital Saint Louis, 1, Avenue Claude Vellefaux, F-75475 Paris Cedex 10, France. Inflammatory breast cancer (IBC) is one of the most aggressive forms of breast cancer. We studied the biological characteristics of these tumours by comparing the overexpression of oncogenes ERBB2, MYC, CCND1 and RHOC and TP53 gene mutation rates in IBC with those found in locally advanced and not otherwise specified breast cancers. The prevalence of the TP53 mutation was much higher in IBC than in the two other types of cancer (57% vs 30). Unexpectedly, however, in IBC tumours, histological grade was independent of TP53 status. In addition, ERBB2 overexpression was twice as frequent in inflammatory as in non-inflammatory tumours, whereas the frequencies of MYC, CCND1 and RHOC overexpression did not vary significantly among the three types of breast cancer. These findings suggest that IBC tumours constitute a distinct subset with a specific pathogenesis. Given the importance of TP53 and ERBB2 in the response to treatments, our observations have important therapeutic implications for the clinical management of IBC patients. PMID: 12386822 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 238: Chem Biol Interact. 2002 Oct 20;141(3):243-57. Induction of apoptosis by penta-acetyl geniposide in rat C6 glioma cells. Chang YC, Tseng TH, Lee MJ, Hsu JD, Wang CJ. Institute of Biochemistry, Chung Shan Medical University, No. 110, Section 2, Chien Kuo N. Road, Taichung, Taiwan. Penta-acetyl geniposide, (Ac)(5)-GP, was produced by acetylation of a glycoside, isolated from an extract of Gardenia fructus. Previously, we have reported that C6 glioma cells could be inhibited in culturing as well as in bearing rats by treating with (Ac)(5)-GP. In this study, the effect and action of (Ac)(5)-GP on inducing cell death was examined in rat C6 glioma cells. Treatment of C6 glioma cells with (Ac)(5)-GP caused cell death, chromatin condensation, and internucleosomal DNA ladder. Also, cell cycle arrest at G(0)/G(1) phase revealed that (Ac)(5)-GP-induced cell death appears to be mediated by apoptosis. In addition, the results also showed that p53 and c-Myc increased due to treatment of (Ac)(5)-GP in a dose-response and time-dependent manner. Concomitant with the expression of p53 and c-Myc, decreased level of Bcl-2 and increased level of Bax protein were observed. These results suggest that cell death caused by (Ac)(5)-GP through apoptosis and cell cycle arrest at G(0)/G(1) may be associated with the induction of p53, c-Myc and may be mediated with apoptosis-related Bcl-2 family proteins. PMID: 12385722 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 239: Nature. 2002 Oct 17;419(6908):729-34. Epub 2002 Oct 2. Myc suppression of the p21(Cip1) Cdk inhibitor influences the outcome of the p53 response to DNA damage. Seoane J, Le HV, Massague J. Cell Biology Program and Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA. Activation of the tumour suppressor p53 by DNA damage induces either cell cycle arrest or apoptotic cell death. The cytostatic effect of p53 is mediated by transcriptional activation of the cyclin-dependent kinase (CDK) inhibitor p21(Cip1), whereas the apoptotic effect is mediated by transcriptional activation of mediators including PUMA and PIG3 (ref. 2). What determines the choice between cytostasis and apoptosis is not clear. Here we show that the transcription factor Myc is a principal determinant of this choice. Myc is directly recruited to the p21(Cip1) promoter by the DNA-binding protein Miz-1. This interaction blocks p21(Cip1) induction by p53 and other activators. As a result Myc switches, from cytostatic to apoptotic, the p53-dependent response of colon cancer cells to DNA damage. Myc does not modify the ability of p53 to bind to the p21(Cip1) or PUMA promoters, but selectively inhibits bound p53 from activating p21(Cip1) transcription. By inhibiting p21(Cip1) expression Myc favours the initiation of apoptosis, thereby influencing the outcome of a p53 response in favour of cell death. PMID: 12384701 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 240: World J Gastroenterol. 2002 Oct;8(5):822-6. Expression of p53 and C-myc genes and its clinical relevance in the hepatocellular carcinomatous and pericarcinomatous tissues. Niu ZS, Li BK, Wang M. Department of Pathology, Medical College of Qingdao University, Qingdao 266021, Shandong Province, China. nzxmxh@public.qd.sd.cn AIM:To investigate the possible roles of p53 and C-myc genes in the primary hepatocellular carcinogenesis and the relationship between the liver hyperplastic nodule (LHN) and hepatocellular carcinoma(HCC). METHODS: The expression of p53 and C-myc genes was detected immunohistochemically in 73 and 60 cases of HCC and pericarcinomatous tissues, respectively. RESULTS: The positive expression of p53 in HCC was significantly higher than that in pericarcinomatous tissues (P<0.05). In pericarcinomatous tissues, the p53 expression was observed only in LHN, but not in liver cirrhosis (LC) and normal liver tissues. The positive expression rate of C-myc in HCC or LHN was significantly higher than that in LC or normal liver tissues (P<0.05 and P<0.01), however, no significant difference was found between HCC and LHN (P>0.05). The positive expression rate of p53 and C-myc in HCC was correlated with the histological differentiation, that in the poorly differentiated was significantly higher than that in well differentiated samples (P<0.05). CONCLUSION: The overexpression of p53 and C-myc genes might play a role in the carcinogenesis of HCC; And LHN seems a preneoplastic lesion related to hepatocarcinogenesis; No evidence supports that LC contribute directly to the hepatocarcinogenesis. PMID: 12378623 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 241: Cancer Genet Cytogenet. 2002 Aug;137(1):33-42. Establishment of a large cell lung cancer cell line (Y-ML-1B) producing granulocyte colony-stimulating factor. Sekido Y, Sato M, Usami N, Shigemitsu K, Mori S, Maeda O, Yokoi T, Hasegawa Y, Yoshioka H, Shimokata K. Department of Clinical Preventive Medicine, Nagoya University School of Medicine, 466-8560, Nagoya, Japan. ysekido@med.nagoya-u.ac.jp We established a new lung cancer cell line, designated Y-ML-1B, from a lung cancer of a 70-year-old Japanese man with leukocytosis and thrombocytosis. Before surgical resection, the white blood cell and platelet counts were elevated to 34,400/mm3 and 668,000/mm3, respectively, and the granulocyte colony-stimulating factor (G-CSF) level in the serum was increased at 141 pg/mL. The primary tumor showed an undifferentiated morphology with large cells and induced extensive thickening of the pleura in the right hemithorax. The Y-ML-1B cells grow as a monolayer, with a doubling time of 19 hours, and are tumorigenic in nude mice, which showed a morphology similar to the primary tumor in xenografts. Analysis of the supernatant of cell culture medium of Y-ML-1B showed elevated levels of G-CSF and other cytokines such as interleukin (IL)-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF), consistent with the high levels detected in the patient's serum. Cytogenetic analysis revealed aneuploidy of greater than 56 in metaphases with many structural abnormalities. Mutation analysis of the tumor suppressor genes showed that Y-ML-1B is inactivated in TP53 and RASSF1A, but not in p14(ARF), p16(INK4A), or RB. Neither activating mutations of KRAS or NRAS nor amplification of MYC or MDM2 were detected. Y-ML-1B expressed N-cadherin but not E-cadherin. This newly established cell line might serve as a useful model for studying the molecular pathogenesis for large cell cancers of the lung which express high levels of cytokines. Publication Types: Case Reports PMID: 12377411 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 242: Oncol Rep. 2002 Nov-Dec;9(6):1299-305. Induction of apoptosis in human choriocarcinoma cell lines by treatment with 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinolinone (vesnarinone). Isaka K, Fujito A, Sagawa Y, Yudate T, Nishi H, Ito H, Takayama M. Department of Obstetrics and Gynecology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan. isaka@tokyo-med.ac.jp Induction of apoptosis is an attractive strategy in cancer therapy but it clinical practice is not yet sufficient in choriocarcinoma. The quinolinone derivative, vesnarinone, is a novel inotropic agent used for treating congestive heart failure and may also have a potential anticancer activity. It induces apoptosis and differentiation in some tumor cell lines. We examined the antitumor effect of vesnarinone in eight cell lines established from human choriocarcinoma and hydatidiform mole using MTT assay and also analyzed the nuclear fragmentation of tumor cells by DNA electrophoresis assay. Vesnarinone inhibited the proliferation of choriocarcinoma cell lines in a dose-dependent manner and induced DNA fragmentation in cells. However, the BM cell line prepared by subcultivation from hydatidiform mole showed no growth suppression or DNA fragmentation in response to vesnarinone. On the other hand, PCR-SSCP analysis and direct DNA sequencing have shown that a human choriocarcinoma cell line, SCH, has a mutant p53 gene at codon 249. When SCH cells were treated with vesnarinone cellular proliferation was significantly inhibited. Vesnarinone suppressed the proliferation of all choriocarcinoma cell lines and induced apoptosis, regardless of the existence of p53 mutation. In addition, it has been found by RT-PCR that expression of c-Myc mRNA is upregulated by treating choriocarcinoma cells with vesnarinone. The finding suggests that vesnarinone might induce expression of c-Myc gene in choriocarcinoma cells, the product of which may be associated with the inhibition of cell growth and induce apoptosis. These results suggest that vesnarinone is a useful reagent for the treatment of choriocarcinoma. PMID: 12375038 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 243: Radiat Environ Biophys. 2002 Sep;41(3):217-24. Epub 2002 Aug 8. Influence of a low background radiation environment on biochemical and biological responses in V79 cells. Satta L, Antonelli F, Belli M, Sapora O, Simone G, Sorrentino E, Tabocchini MA, Amicarelli F, Ara C, Ceru MP, Colafarina S, Conti Devirgiliis L, De Marco A, Balata M, Falgiani A, Nisi S. Energetics Department, Rome University "La Sapienza", Via A. Scarpa 14, 00161 Rome Italy, Luigi.Satta@lnf.infn.it We present the results of an experiment aimed at comparing the effects of different background radiation environments on metabolism and responses to gamma-rays and cycloheximide of cultured mammalian cells. Chinese hamster V79 cells were maintained in exponential growth in parallel for up to 9 months at the Istituto Superiore di Sanita (ISS) and at the INFN-Gran Sasso underground Laboratory (LNGS) where exposure due to gamma-rays and to radon was reduced by factors of about 70 and 25, respectively. After 9 months the cells grown at the LNGS (cumulative gamma dose about 30 microGy, average radon concentration around 5 Bq/m(3)), compared to the cells grown at the ISS (cumulative gamma-ray dose about 2 mGy, average radon concentration around 120 Bq/m(3)), exhibited i). a significant increase of the cell density at confluence, ii). a significantly higher capacity to scavenge organic and inorganic hydroperoxides but a reduced scavenging capacity towards superoxide anions and iii). an increase in both the basal hprt mutation frequency and sensitivity to the mutagenic effect of gamma-rays. The cells grown at the LNGS also showed a greater apoptotic sensitivity starting at the third month of culture, that was no longer detected after 9 months. Overall, these data suggest a role of background ionizing radiation in determining an adaptive response, although they cannot be considered conclusive. PMID: 12373331 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 244: Cell. 2002 Oct 4;111(1):41-50. Erratum in: Cell 2002 Dec 27;111(7):1055. The circadian gene Period2 plays an important role in tumor suppression and DNA damage response in vivo. Fu L, Pelicano H, Liu J, Huang P, Lee C. Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. The Period2 gene plays a key role in controlling circadian rhythm in mice. We report here that mice deficient in the mPer2 gene are cancer prone. After gamma radiation, these mice show a marked increase in tumor development and reduced apoptosis in thymocytes. The core circadian genes are induced by gamma radiation in wild-type mice but not in mPer2 mutant mice. Temporal expression of genes involved in cell cycle regulation and tumor suppression, such as Cyclin D1, Cyclin A, Mdm-2, and Gadd45alpha, is deregulated in mPer2 mutant mice. In particular, the transcription of c-myc is controlled directly by circadian regulators and is deregulated in the mPer2 mutant. Our studies suggest that the mPer2 gene functions in tumor suppression by regulating DNA damage-responsive pathways. PMID: 12372299 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 245: Oncogene. 2002 Oct 3;21(44):6819-28. Synergistic and opposing regulation of the stress-responsive gene IEX-1 by p53, c-Myc, and multiple NF-kappaB/rel complexes. Huang YH, Wu JY, Zhang Y, Wu MX. Department of Pathology, Baylor College of Medicine, Houston, Texas, TX 77030, USA. NF-kappaB/rel proteins, tumor suppressor p53, and oncogene c-Myc are critical transcription factors involved in coordinating cellular decision-making events in response to external stimuli. Consensus sequences for binding these three transcription factors are found in the promoter region of IEX-1 (Immediate Early response gene X-1) gene that can either suppress or induce apoptosis in a cell- and stimulus-dependent manner. Utilizing an electrophoretic mobility shift assay (EMSA) and a promoter/reporter assay, we show that the NF-kappaB/rel consensus sequence in the IEX-1 promoter is specifically bound and activated by multiple NF-kappaB/rel complexes in descending order p65-c-rel-->p65-50-->p50-50. Interestingly, NF-kappaB/rel-mediated activation of IEX-1 expression was synergized by p53, but strongly inhibited by c-Myc in a dose-dependent fashion. Moreover, the ability of c-Myc to inhibit IEX-1 expression requires the presence of functional p53, which may partially contribute to the varying effects of p53 on IEX-1 expression in different cells. In support of coordinated regulation of IEX-1 expression by these three transcription factors in vivo, binding of endogenous p53, c-Myc and NF-kappaB/rel proteins, including p50, p65 and c-rel, to the IEX-1 promoter was demonstrated in living cells by chromatin immunoprecipitation using specific antibodies. The study reveals a novel integrative regulation of specific gene expression by NF-kappaB/rel, p53 and c-Myc transcription factors. PMID: 12360408 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 246: Int J Oncol. 2002 Oct;21(4):695-706. Comprehensive genotypic analysis of human prostate cancer cell lines and sublines derived from metastases after orthotopic implantation in nude mice. Lensch R, Gotz C, Andres C, Bex A, Lehmann J, Zwergel T, Unteregger G, Kamradt J, Stoeckle M, Wullich B. Department of Urology and Pediatric Urology, University of the Saarland, D-66421 Homburg/Saar, Germany. We recently reported on a prostate cancer progression model which was based on repeated orthotopic implantation of human prostate cancer cell lines into athymic nude mice leading to an increase of tumor cell aggressiveness. To assess progression-associated clonal evolution of genotypic changes, we now performed comparative cytogenetic characterization of the original cell lines DU145 and PC3 with derived sublines DU145MN1 and PC3-N. Cell line PC3-125-1L, isolated from a lung metastasis after subcutaneous inoculation of PC3 into nude mice, was included in the study. Whole-genome analysis was performed using spectral karyotyping and comparative genomic hybridization. Fluorescence in situ hybridization was used to assess amplification of selected genes, which are supposed to play a role in prostate cancer progression. Differences in the genetic constitution between parental cell lines and sublines involved gains of genetic material at 2q, 5q, 12p/q, and 18p as well as losses at 6p, 7q, 17p, 18q, and 22q. Loss of 17p in DU145MN1 and high-level amplification of MYC in PC3-125-1L resulted in loss of p53 expression and upregulation of Myc expression, respectively, as was assessed by Western blotting. Thus, the nude mice model is very useful to follow clonal evolution of genetic changes during increase of prostate cancer aggressiveness and possibly to clone genes associated with the progression of prostate cancer. PMID: 12239607 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 247: Oncogene. 2002 Sep 19;21(42):6498-509. E2F activity is essential for survival of Myc-overexpressing human cancer cells. Santoni-Rugiu E, Duro D, Farkas T, Mathiasen IS, Jaattela M, Bartek J, Lukas J. Department of Cell Cycle and Cancer, Institute of Cancer Biology, Danish Cancer Society, 2100 Copenhagen E., Denmark. bartek@biobase.dk Effective cell cycle completion requires both Myc and E2F activities. However, whether these two activities interact to regulate cell survival remains to be tested. Here we have analysed survival of inducible c-Myc-overexpressing cell lines derived from U2OS human osteosarcoma cells, which carry wild-type pRb and p53 and are deficient for p16 and ARF expression. Induced U2OS-Myc cells neither underwent apoptosis spontaneously nor upon reconstitution of the ARF-p53 axis and/or serum-starvation. However, they died massively when concomitantly exposed to inhibitors of E2F activity, including a constitutively active pRb (RbDeltacdk) mutant, p16, a stable p27 (p27T187A) mutant, a dominant-negative (dn) CDK2, or dnDP-1. Similar apoptotic effect was observed upon down-modulation of endogenous E2Fs through overexpression of E2F binding site oligonucleotides in U2OS-Myc cells, upon expression of RbDeltacdk or dnDP-1 in the Myc-amplified HL-60 (ARF-; p53-) human leukemia cells, and upon co-transfection of Myc and RbDeltacdk in SAOS-2 (ARF+; p53-) human osteosarcoma cells but not in human primary fibroblasts. Consistent with these results, a dnp53 mutant did not abrogate the Myc-induced apoptotic phenotype, which instead strictly depended on caspase-3-like proteases and on Myc transcriptional activity. Our data indicate that in contrast to normal cells, Myc-overexpressing human cancer cells need E2F activity for their survival, regardless of their ARF and p53 status, a notion that may have important implications for antineoplastic treatment strategies. PMID: 12226753 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 248: Prog Nucleic Acid Res Mol Biol. 2002;72:367-413. Translational control of gene expression: role of IRESs and consequences for cell transformation and angiogenesis. Prats AC, Prats H. Institut National de la Sante et de la Recherche Medicale U397, Endocrinologie et Communication Cellulaire, CHU Rangueil Toulouse, France. Translational control of gene expression has, over the last 10 years, become appreciated as an important process in its regulation in eukaryotes. Among a series of control mechanisms exerted at the translational level, the use of alternative codons provides a very subtle means of increasing gene diversity by expressing several proteins from a single mRNA. The internal ribosome entry sites (IRESs) act as specific translational enhancers that allow translation initiation to occur independently of the classic cap-dependent mechanism, in response to specific stimuli and under the control of different trans-acting factors. It is striking to observe that the two processes mostly concern genes coding for control proteins such as growth factors, protooncogenes, angiogenesis factors, and apoptosis regulators. Here, we focus on the translational regulation of four mRNAs, with both IRESs and alternative initiation codons, which are the messengers of retroviral murine leukemia virus, fibroblast growth factor 2, vascular endothelial growth factor, and protooncogene c-myc. Four of them are involved in cell transformation and/or angiogenesis, with important consequences for such translation regulations in these pathophysiological processes. Publication Types: Review PMID: 12206457 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 249: Genes Chromosomes Cancer. 2002 Oct;35(2):127-37. Multicolor COBRA-FISH analysis of chronic myeloid leukemia reveals novel cryptic balanced translocations during disease progression. Barbouti A, Johansson B, Hoglund M, Mauritzson N, Strombeck B, Nilsson PG, Tanke HJ, Hagemeijer A, Mitelman F, Fioretos T. Department of Clinical Genetics, Lund University Hospital, Lund, Sweden. Aikaterini.Barmpouti@klingen.lu.se During the initial indolent chronic phase of chronic myeloid leukemia (CML), the t(9;22)(q34;q11), resulting in the Philadelphia chromosome (Ph), is usually the sole cytogenetic anomaly, but as the disease progresses into the accelerated phase (AP), and eventually into aggressive blast crisis (BC), secondary aberrations, mainly unbalanced changes such as +8, i(17q), and +Ph, are frequent. To date, molecular genetic studies of CML BC have mainly focused on alterations of well-known tumor-suppressor genes (e.g., TP53, CDKN2A, and RB1) and oncogenes (e.g., RAS and MYC), whereas limited knowledge is available about the molecular genetic correlates of the unbalanced chromosomal abnormalities. Balanced secondary changes are rare in CML AP/BC, but it is not known whether cryptic chromosomal translocations, generating fusion genes, may be responsible for disease progression in a subgroup of CML. To address this issue, we used multicolor combined binary ratio fluorescence in situ hybridization (FISH), which allows the simultaneous visualization of all 24 chromosomes in different colors, verified by locus-specific FISH in a series of 33 CML cases. Two cryptic balanced translocations, t(7;17)(q32-34;q23) and t(7;17)(p15;q23), were found in two of the five cases showing the t(9;22) as the only cytogenetic change. Using several BAC clones, the breakpoints at 17q23 in both cases were mapped within a 350-kb region. In the case with the 7p15 breakpoint, a BAC clone containing the HOXA gene cluster displayed a split signal, suggesting a possible creation of a fusion gene involving a member of the HOXA family. Furthermore, one case with a partially cryptic t(9;11)(p21-22;q23) and an MLL rearrangement as well as a previously unreported t(3;10)(p22;p12-13) were identified. Altogether, a refined karyotypic description was achieved in 12 (36%) of the 33 investigated cases, illustrating the value of using multicolor FISH for identifying pathogenetically important aberrations in CML AP/BC. Copyright 2002 Wiley-Liss, Inc. PMID: 12203776 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 250: Oncogene. 2002 Sep 5;21(39):6113-22. Novel target for induction of apoptosis by cyclo-oxygenase-2 inhibitor SC-236 through a protein kinase C-beta(1)-dependent pathway. Jiang XH, Lam SK, Lin MC, Jiang SH, Kung HF, Slosberg ED, Soh JW, Weinstein IB, Wong BC. Department of Gastroenterology, Rui-jin Hospital, Shanghai, PR China. Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the risk of gastrointestinal cancers. Recently, a similar protective effect has been demonstrated by the specific cyclo-oxygenase-2 (COX-2) inhibitors. However, the exact mechanism that accounts for the anti-proliferative effect of specific COX-2 inhibitors is still not fully understood, and it is still controversial whether these protective effects are predominantly mediated through the inhibition of COX-2 activity and prostaglandin synthesis. Identification of molecular targets regulated by COX-2 inhibitors could lead to a better understanding of their pro-apoptotic and anti-neoplastic activities. In the present study, we investigated the effect and the possible molecular target of a COX-2-specific inhibitor SC-236 on gastric cancer. We showed that SC-236 induced apoptosis in gastric cancer cells. However, this effect was not dependent on COX-2 inhibition. SC-236 down-regulated the protein expression and kinase activity of PKC-beta(1), increased the expression of PKCdelta and PKCeta, but did not alter the expression of other PKC isoforms in AGS cells. Moreover, exogenous prostaglandins or PGE(2) receptor antagonists could not reverse the inhibition effect on PKCbeta(1) by SC-236, which suggested that this effect occurred through a mechanism independent of cyclo-oxygenase activity and prostaglandin synthesis. Overexpression of PKCbeta(1) attenuated the apoptotic response of AGS cells to SC-236 and was associated with overexpression of p21(waf1/cip1). Inhibition of PKCbeta(1)-mediated overexpression of p21(waf1/cip1) partially reduced the anti-apoptotic effect of PKCbeta(1). The down-regulation of PKCbeta(1) provides an explanation for COX-independent apoptotic effects of specific COX-2 inhibitor in cultured gastric cancer cells. We also suggest that PKCbeta(1) act as survival mediator in gastric cancer, and its down-regulation by COX-2 inhibitor SC-236 may provide new target for future treatment of gastric cancer. PMID: 12203123 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 251: Int J Biochem Cell Biol. 2002 Nov;34(11):1382-94. Molecular changes accompanying senescence and immortalization of cultured human mammary epithelial cells. Yaswen P, Stampfer MR. Department of Cell and Molecular Biology, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Mailstop 70A-1118, Berkeley, CA 94720, USA. p_yaswen@lbl.gov Limits on the proliferative potential of cultured normal human cells may be consequences of pathways that exist to suppress tumorigenicity. Human mammary epithelial cells (HMEC) employ several mechanisms to prevent unlimited growth. One mechanism may be activated by stress, and is associated with upregulated expression of p16(INK4a). In serum-free medium, some HMEC arise spontaneously which do not express p16. These "post-selection" HMEC are capable of long-term proliferation, but ultimately cease growth when their telomeres become very short. As they approach a growth plateau, termed agonescence, post-selection HMEC populations accumulate chromosome abnormalities. In contrast to the crisis exhibited by cells lacking functional p53, agonescent cells can be maintained as viable cultures. Although transduction of hTERT, the catalytic subunit of telomerase, into post-selection cells can, by itself, efficiently produce immortality and avoid agonescence, the errors that produce telomerase reactivation during carcinogenesis are not known. The block to endogenous telomerase reactivation in HMEC is extremely stringent. However, if one predisposing error is present, the probability greatly increases that additional error(s) required for immortalization may be generated by genomic instability encountered during agonescence. In p53(+) HMEC immortalized after chemical carcinogen exposure, the events involved in overcoming agonescence can be temporally separated from activation of telomerase. We have used the term "conversion" to describe the gradual process that leads to telomerase activation, telomere length stabilization, decreased p57 (KIP2) expression, and increased ability to grow uniformly well in the presence or absence of TGF beta. In the presence of active p53, conversion may represent a rate-limiting step in immortal transformation. Publication Types: Review Review, Tutorial PMID: 12200033 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 252: Semin Cancer Biol. 2002 Oct;12(5):381-7. Role of genetic and epigenetic changes in Burkitt lymphoma. Lindstrom MS, Wiman KG. Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, R8:04 Karolinska Hospital, SE-17176 Stockholm, Sweden. All Burkitt lymphomas (BLs) carry reciprocal chromosomal translocations that activate the c-myc oncogene through juxtaposition to one of the immunoglobulin (Ig) loci. Many BL carry point mutation in the p53 tumor suppressor gene or other defects in the p14ARF-MDM2-p53 pathway, and inactivation of the p16INK4a gene by promoter methylation or homozygous deletion. This indicates that disruption of both the pRb and p53 tumor suppressor pathways is critical for BL development. Alterations of other genes, including Bax, p73, and BCL-6, may provide further growth stimulation and apoptosis protection. Thus, BL development involves multiple genetic and epigenetic changes that drive cell cycle progression and avert cell death by apoptosis. Publication Types: Review Review, Tutorial PMID: 12191637 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 253: J Exp Med. 2002 Aug 19;196(4):469-80. Evidence for replicative repair of DNA double-strand breaks leading to oncogenic translocation and gene amplification. Difilippantonio MJ, Petersen S, Chen HT, Johnson R, Jasin M, Kanaar R, Ried T, Nussenzweig A. Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. difilipm@mail.nih.gov Nonreciprocal translocations and gene amplifications are commonly found in human tumors. Although little is known about the mechanisms leading to such aberrations, tissue culture models predict that they can arise from DNA breakage, followed by cycles of chromatid fusion, asymmetric mitotic breakage, and replication. Mice deficient in both a nonhomologous end joining (NHEJ) DNA repair protein and the p53 tumor suppressor develop lymphomas at an early age harboring amplification of an IgH/c-myc fusion. Here we report that these chromosomal rearrangements are initiated by a recombination activating gene (RAG)-induced DNA cleavage. Subsequent DNA repair events juxtaposing IgH and c-myc are mediated by a break-induced replication pathway. Cycles of breakage-fusion-bridge result in amplification of IgH/c-myc while chromosome stabilization occurs through telomere capture. Thus, mice deficient in NHEJ provide excellent models to study the etiology of unbalanced translocations and amplification events during tumorigenesis. PMID: 12186839 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 254: J Cell Mol Med. 2002 Apr-Jun;6(2):215-22. MYCL1, FHIT, SPARC, p16(INK4) and TP53 genes associated to lung cancer in idiopathic pulmonary fibrosis. Demopoulos K, Arvanitis DA, Vassilakis DA, Siafakas NM, Spandidos DA. Department of Virology, Medical School, University of Crete, P.O. Box 1393, Heraklion, Crete, Greece. Idiopathic pulmonary fibrosis (IPF) is a specific form of chronic interstitial pneumonia limited to the lung and characterized by a fibroproliferative response with only minor signs of inflammation, which almost always causes rapid fibrotic destruction of the lung. In this study, we investigated genomic instability in IPF, using microsatellite DNA analysis, aiming to detect any specific genetic alterations for this disease. We used 40 highly polymorphic microsatellite DNA markers, in multiplex PCR assays, to examine 52 sputum specimens from IPF patients versus correspondent venous blood. Loss of heterozygosity (LOH) was found in 20 (38.5%) patients in at least one locus. These alterations were found on markers previously associated with lung cancer located on 1p34.3, 3p21.32-p21.1, 5q32-q33.1, 9p21 and 17p13.1 where MYCL1, FHIT, SPARC, p16(Ink4) and TP53 genes have been mapped respectively. These data provide new insights into IPF pathogenesis and a new perspective for its correlation with lung cancer. PMID: 12169206 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 255: Mol Cell Biol. 2002 Sep;22(17):6158-69. c-Myc functionally cooperates with Bax to induce apoptosis. Juin P, Hunt A, Littlewood T, Griffiths B, Swigart LB, Korsmeyer S, Evan G. University of California at San Francisco Cancer Center, San Francisco, California 94143-0128, USA. c-Myc promotes apoptosis by destabilizing mitochondrial integrity, leading to the release of proapoptotic effectors including holocytochrome c. Candidate mediators of c-Myc in this process are the proapoptotic members of the Bcl-2 family. We show here that fibroblasts lacking Bak remain susceptible to c-Myc-induced apoptosis whereas bax-deficient fibroblasts are resistant. However, despite this requirement for Bax, c-Myc activation exerts no detectable effects on Bax expression, localization, or conformation. Moreover, susceptibility to c-Myc-induced apoptosis can be restored in bax-deficient cells by ectopic expression of Bax or by microinjection of a peptide comprising a minimal BH3 domain. Microinjection of BH3 peptide also restores sensitivity to c-Myc-induced apoptosis in p53-deficient primary fibroblasts that are otherwise resistant. By contrast, there is no synergy between BH3 peptide and c-Myc in fibroblasts deficient in both Bax and Bak. We conclude that c-Myc triggers a proapoptotic mitochondrial destabilizing activity that cooperates with proapoptotic members of the Bcl-2 family. PMID: 12167710 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 256: J Biol Chem. 2002 Oct 18;277(42):39769-76. Epub 2002 Aug 6. p73 independent of c-Myc represses transcription of platelet-derived growth factor beta-receptor through interaction with NF-Y. Hackzell A, Uramoto H, Izumi H, Kohno K, Funa K. Department of Cell Biology, Institute of Anatomy and Cell Biology, Goteborg University, Box 420, SE-405 30 Gothenburg, Sweden. We recently reported that c-Myc represses the transcription of platelet-derived growth factor (PDGF) beta-receptor (Izumi, H., Molander, C., Penn, L. Z., Ishisaki, A., Kohno, K., and Funa, K. (2001) J. Cell Sci. 114, 1533-1544). We demonstrate here that the p53 family protein p73alpha represses PDGF beta-receptor transcription essentially by the same mechanism. p73alpha but not p73beta or p53 represses the transcription in concordance with its ability to bind NF-YC and NF-YB. None of other p73 isoforms (i.e. p73beta, p73gamma, p73epsilon), C-terminal deletion mutants of p73alpha, and p53 is able to bind NF-Y with the exception of p63alpha. This finding suggests that the sterile alpha-motif domain present only in p73alpha and p63alpha is the interaction site. For the repression, the N-terminal transactivation domain of p73alpha is also indispensable, arguing for the importance of the activity of p73alpha in the mechanism. p73alpha binds the C-terminal HAP domain of NF-YC previously found to be the interaction site with c-Myc and TBP. Because c-Myc induces and activates p73alpha (Zaika, A., Irwin, M., Sansome, C., and Moll, U. M. (2001) J. Biol. Chem. 276, 11310-11316) and they bind each other (Uramoto, H., Izumi, H., Ise, T., Tada, M., Uchiumi, T., Kuwano, M., Yasumoto, K., Funa, K., and Kohno, K. (2002) J. Biol. Chem. 277, in press), we examined whether the repression by p73 is dependent on c-Myc. However, Myc-null rat fibroblasts are also susceptible to p73alpha-induced repression. Serum stimulation of NIH3T3 cells gradually decreased the amount of endogenous NF-Y binding to the PDGF beta-receptor promoter, whereas NF-YA expression in the nuclear extracts remains unchanged. Our results indicate that serum stimulation induces c-Myc and p73alpha, leading to the down-regulation of PDGF beta-receptor expression by repressing its transcription. PMID: 12167641 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 257: Virology. 2002 Jul 20;299(1):72-87. Cellular steady-state levels of "high risk" but not "low risk" human papillomavirus (HPV) E6 proteins are increased by inhibition of proteasome-dependent degradation independent of their p53- and E6AP-binding capabilities. Kehmeier E, Ruhl H, Voland B, Stoppler MC, Androphy E, Stoppler H. Department of Pharmacology and Toxicology, Philipps University Marburg, Karl-von-Frisch Strasse 1, D-35033, Germany. The group of mucosal epithelia-infecting human papillomaviruses (HPV) can be subdivided in "low" and "high risk" HPV types. Both types induce benign neoplasia (condyloma), but only the infection with a "high risk" HPV type is causally associated with an increased risk of developing anogenital tumors. The oncogenic potential of high risk HPVs resides at least partially in the viral E6 protein. The E6 protein targets the cellular p53 protein for proteasome-dependent degradation, which is associated with the immortalizing and transforming functions of these viruses. Recently the E6-dependent proteasome-mediated destabilization of additional cellular proteins (E6TP1, c-myc, Bak, hMCM7, human scribble, E6AP, MAGI-1) has been described, but the cellular mechanisms controlling the viral E6 protein stability itself have been so far not analyzed. In this study, we transiently expressed the E6 genes of the high risk HPV type 16, the low risk HPV types 6a and 11, and the cutaneous epithelia-infecting HPV types 5 and 8 from a eucaryotic expression vector and compared the cellular steady-state levels of the expressed E6 proteins. We demonstrated that the high risk HPV 16 E6 protein possesses the lowest steady-state level in comparison to the low risk HPV type E6 proteins and the cutaneous epithelia-infecting HPV type E6 proteins. Inhibition of cellular proteasome-dependent protein degradation led to an increase in steady-state levels of high risk but not of low risk E6 proteins. Analysis of functionally deficient HPV 16 E6 proteins in p53 null- and p53 wild-type-expressing cell lines revealed that the cellular steady-state level of this protein is influenced neither by its p53- nor its E6AP-binding abilities. PMID: 12167343 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 258: J Gastroenterol Hepatol. 2002 Sep;17(9):966-72. Apoptosis and cell proliferation in the development of gastric carcinomas: associations with c-myc and p53 protein expression. Ishii HH, Gobe GC, Pan W, Yoneyama J, Ebihara Y. Second Department of Pathology, Tokyo Medical University, Japan. hhishii@tokyo-med.ac.jp BACKGROUND AND AIM: Patients with gastric carcinomas have a poor prognosis and low survival rates. The aim of the present paper was to characterize cellular and molecular properties to provide insight into aspects of tumor progression in early compared with advanced gastric cancers. METHODS: One hundred and nine graded gastric carcinomas (early or advanced stage, undifferentiated or differentiated type) with paired non-cancer tissue were studied to define the correlation between apoptosis (morphology, terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling), cell proliferation (Ki-67 expression, morphology) and expression and localization of two proteins frequently having altered expression in cancers, namely p53 and c-myc. RESULTS: Overall, apoptosis was lower in early stage, differentiated and undifferentiated gastric carcinomas compared with advanced-stage cancers. Cell proliferation was comparatively high in all stages. There was a high level of p53 positivity in all stages. Only the early- and advanced-stage undifferentiated cancers that were p53 positive had a significantly higher level of apoptosis (P < 0.05). Cell proliferation was significantly greater (P < 0.05) only in the early undifferentiated cancers that had either c-myc or p53-positivity. CONCLUSIONS: The results indicate that low apoptosis and high cell proliferation combine to drive gastric cancer development. The molecular controls for high cell proliferation of the early stage undifferentiated gastric cancers involve overexpression of both p53 and c-myc. Overexpression of p53 may also control cancer development in that its expression is associated with higher levels of apoptosis in early and late-stage undifferentiated, cancers. Copyright 2002 Blackwell Publishing Asia Pty Ltd PMID: 12167117 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 259: Minerva Chir. 2002 Aug;57(4):437-48. Biomarkers for breast cancer. Beenken SW, Bland KI. Department of Surgery, University of Alabama at Birmingham and University of Alabama Hospital, Birmingham, AL, USA. samuel.beenken@ccc.uab.edu Molecular biomarkers for breast cancer are of several types. Risk biomarkers are those associated with increased cancer risk and include mammographic abnormalities, proliferative breast disease with or without atypia, family clustering and inherited germ-line abnormalities. Surrogate endpoint biomarkers are tissue, cellular or molecular alterations that occur between cancer initiation and progression. These biomarkers are utilized as endpoints in short-term chemoprevention trials. Prognostic biomarkers provide information regarding outcome irrespective of therapy, while predictive biomarkers provide information regarding response to therapy. Candidate prognostic biomarkers for breast cancer include elevated proliferation indices such as Ki-67 and proliferating cell nuclear antigen (PCNA); ER and PR overexpression; markers of oncogene overexpression such as c-erbB-2, TGF-a and EGFr; indicators of apoptotic imbalance including overexpression of bcl-2 and an increased bax/bcl-2 ratio; markers of disordered cell signaling such as p53 nuclear protein accumulation; alteration of differentiation signals such as overexpression of c-myc and related proteins; loss of differentiation markers such as TGF-b II receptor and retinoic acid receptor; and alteration of angiogenesis proteins such as VEGF overexpression. As our knowledge regarding molecular biomarkers for breast cancer increases, prognostic indices will be developed that combine the predictive power of individual molecular biomarkers with specific clinical and pathologic factors. Publication Types: Review Review, Tutorial PMID: 12145573 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 260: Oncogene. 2002 Aug 1;21(33):5097-107. Mammary tumors in mice conditionally mutant for Brca1 exhibit gross genomic instability and centrosome amplification yet display a recurring distribution of genomic imbalances that is similar to human breast cancer. Weaver Z, Montagna C, Xu X, Howard T, Gadina M, Brodie SG, Deng CX, Ried T. Genetics Branch, Center for Cancer Research, National Cancer Institute/NIH, Bethesda, Maryland 20892, USA. BRCA1 mutation carriers have an increased susceptibility to breast and ovarian cancer. Excision of exon 11 of Brca1 in the mouse, using a conditional knockout (Cre-loxP) approach, results in mammary tumor formation after long latency. To characterize the genomic instability observed in these tumors, to establish a comparative map of chromosomal imbalances and to contribute to the validation of this mouse model of breast cancer, we have characterized chromosomal imbalances and aberrations using comparative genomic hybridization (CGH), and spectral karyotyping (SKY). We found that all tumors exhibit chromosome instability as evidenced by structural chromosomal aberrations and aneuploidy, yet they display a pattern of chromosomal gain and loss that is similar to the pattern in human breast carcinomas. Of note, nine of 15 tumors exhibited a gain of distal chromosome 11, a region that is orthologous to human chromosome 17q11-qter, the mapping position of Erbb2. However, our analysis suggests that genes distal to Erbb2 are the main targets of amplification. Four of the tumors also exhibited a copy number loss of proximal chromosome 11 (11A-B), a region orthologous to human 17p. In eight of the tumors we observed whole or partial gain of chromosome 15 centering on 15D2-D3 (orthologous to human chromosome 8q24), the map location of the c-Myc gene, and six of the tumors exhibited copy number loss of whole or partial chromosome 14, including 14D3, the map location of Rb1. We conclude that despite the tremendous shuffling of chromosomes during the course of mammalian evolution, the pattern of genomic imbalances is conserved between BRCA1-associated mammary gland tumors in mice and humans. Western blot analysis showed that while p53 is absent or mutated in some tumors, at least two tumors revealed wild-type protein, suggesting that other genetic events may lead to tumorigenesis. Similar to BRCA1-deficient mouse embryonic fibroblasts, the tumor cells contained supernumerary functional centrosomes with intact centrioles whose presence results in multipolar mitoses and aneuploidy. PMID: 12140760 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 261: Toxicology. 2002 Aug 15;177(2-3):253-65. Cadmium affects genes involved in growth regulation during two-stage transformation of Balb/3T3 cells. Fang MZ, Mar W, Cho MH. Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Suwon, South Korea. Cadmium (Cd), a carcinogenic metal in human and rodents, has been shown to transform cells in vitro. However, the carcinogenic mechanisms of Cd as a mutagen and/or promoter are not well clarified. We already reported that CdCl2 in a range of 1.5 approximately 360 ng/ml enhanced transformation of Balb/3T3 A31 cells induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG, 0.1 microg/ml) in a dose-dependent manner (Fang et al., Toxicol. In Vitro 15(3) (2001a) 51-7). In previous study, we observed that Cd stimulated cell proliferation on MNNG-initiated cells through inactivation of p53 and p27 and increase of proliferating cell nuclear antigen (PCNA) expression after 24 h treatment (Fang et al., Toxicology 163 (2001b) 175-84). The aim of this study is to further elucidate the long-term effect of Cd in terms of cell cycle control gene expressions during the promotion stage of in vitro two-stage transformation. For the purpose, we determined the expression levels of the genes involved in growth regulation, such as p53, p27, c-myc, mdm2, cyclins D1 and B1, CDK4, and PCNA in the cells treated with Cd for 14 days after MNNG-initiation. In MNNG+CdCl2 group, cells apparently expressed cellular tumor antigen p53 mRNA, but did not express the wild-type p53 protein; the protein and mRNA levels of p27 were reduced apparently in the cells of MNNG+CdCl2 group compared to the cells of control and MNNG group. In addition, the protein levels of cyclin D1, CDK4, PCNA, c-myc, and mdm2, and cyclin B1 mRNA level were higher in MNNG+CdCl2 group than control and MNNG group. Together with previous data (Fang et al., Toxicology 163 (2001b) 175-84), our results indicated that during the transformation process of MNNG-treated cells, Cd may activate oncogenes such as c-myc, mdm2, and cellular tumor antigen p53, inhibit the tumor suppressor genes such as wild-type p53 and p27, and consequently accelerate the proliferation of initiated cells. This work firstly demonstrates that Cd affects the genes involved in growth regulation on initiated cells during the promotion stage of in vitro cell transformation. PMID: 12135628 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 262: Cell. 2002 Jun 28;109(7):811-21. Unrepaired DNA breaks in p53-deficient cells lead to oncogenic gene amplification subsequent to translocations. Zhu C, Mills KD, Ferguson DO, Lee C, Manis J, Fleming J, Gao Y, Morton CC, Alt FW. Howard Hughes Medical Institute, The Children's Hospital and The Center for Blood Research, Boston MA 02115, USA. Amplification of large genomic regions associated with complex translocations (complicons) is a basis for tumor progression and drug resistance. We show that pro-B lymphomas in mice deficient for both p53 and nonhomologous end-joining (NHEJ) contain complicons that coamplify c-myc (chromosome 15) and IgH (chromosome 12) sequences. While all carry a translocated (12;15) chromosome, coamplified sequences are located within a separate complicon that often involves a third chromosome. Complicon formation is initiated by recombination of RAG1/2-catalyzed IgH locus double-strand breaks with sequences downstream of c-myc, generating a dicentric (15;12) chromosome as an amplification intermediate. This recombination event employs a microhomology-based end-joining repair pathway, as opposed to classic NHEJ or homologous recombination. These findings suggest a general model for oncogenic complicon formation. PMID: 12110179 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 263: Nippon Rinsho. 2002 May;60 Suppl 5:78-82. [Genetic alteration in lung cancer] [Article in Japanese] Hashimoto T, Hayashi M, Tsuchiya E. Division of Thoracic and Cardiovascular Surgery, Niigata University Graduate School of Medical and Dental Sciences. Publication Types: Review Review, Tutorial PMID: 12101778 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 264: Nippon Geka Gakkai Zasshi. 2002 Jun;103(6):482-6. [Genetic investigations for lung carcinoma] [Article in Japanese] Shirakusa T, Noda N, Matsuzoe D. Second Department of Surgery, Fukuoka University School of Medicine, Fukuoka, Japan. Lung carcinoma is a common malignant disease in adults. Various genetic changes associated with small cell and non-small cell lung carcinoma are now known. There are two types of genetic change which influence tumor growth and patient prognosis. Among oncogenes, c-myc, K-ras, and erbB-2 are considered to play important roles in lung carcinogenesis. The p53 suppressor gene is highly expressed in small and non-small cell carcinoma. To differentiate between double primary lung carcinomas and intrapulmonary metastasis, or between primary lung carcinoma and metastatic lung tumor, the analysis of gene mutations, such as of p53 and K-ras, appears to be very useful. PMID: 12094700 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 265: Planta Med. 2002 Jun;68(6):550-3. Apoptosis of human highly metastatic lung cancer cell line 95-D induced by acutiaporberine, a novel bisalkaloid derived from Thalictrum acutifolium. Chen Q, Peng W, Qi S, Xu A. The present study demonstrates for the first time that acutiaporberine, a bisalkaloid isolated from the tranditional Chinese medical herb Thalictrum acutifolium (Hand.-Mazz.) Boivin. (TAB), induces apoptosis of a cultured highly metastatic human lung cancer cell line 95-D. Immunohistochemistry assay (IHC) and Western-blot analysis show down-regulation of bcl-2 gene and up-regulation of bax gene and c-myc gene in the treated cells. These results suggest that acutiaporberine may be a natural potential apoptosis-inducing agent for highly metastatic lung cancer. Publication Types: Letter PMID: 12094304 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 266: Virology. 2002 Jun 20;298(1):53-62. Hepatitis C virus core protein is necessary for the maintenance of immortalized human hepatocytes. Basu A, Meyer K, Ray RB, Ray R. Department of Internal Medicine, Saint Louis University, Missouri 63110, USA. Hepatitis C virus (HCV) core protein has many intriguing properties and plays an important role in cell growth regulation. We have recently shown that the HCV core protein from genotype 1a promotes primary human hepatocytes to an immortalized phenotype. Here, we investigated whether the presence of core protein is necessary for maintenance of the immortalized hepatocytes and investigated its consequences on cellular gene expression. The introduction of an antisense orientation of the core gene into immortalized hepatocytes led to the onset of cell death. Further analysis suggested that cell death occurred through apoptosis associated with the activation of tumor suppressor pathways. Antisense core gene expression in immortalized hepatocytes increased p53 expression at both the mRNA and the protein levels. A decreased telomere length and reduced c-myc protein expression were also observed in hepatocytes when the antisense core gene was introduced. Results from these studies suggested that modulation of cell cycle regulatory genes by repression of core protein expression is responsible for reversion of the immortalized phenotype of the hepatocytes. Thus, targeted inhibition may contribute to the development of new therapeutic modalities for prevention of HCV core protein function. (c) 2002 Elsevier Science (USA). PMID: 12093173 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 267: Cancer Cell. 2002 Feb;1(1):53-62. Comment in: Cancer Cell. 2002 Feb;1(1):11-2. Induction of ovarian cancer by defined multiple genetic changes in a mouse model system. Orsulic S, Li Y, Soslow RA, Vitale-Cross LA, Gutkind JS, Varmus HE. Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA. orsulics@mskcc.org We have developed a mouse model for ovarian carcinoma by using an avian retroviral gene delivery technique for the introduction of multiple genes into somatic ovarian cells of adult mice. Ovarian cells from transgenic mice engineered to express the gene encoding the avian receptor TVA were efficiently infected in vitro with multiple vectors carrying coding sequences for oncogenes and marker genes. When target cells were derived from TVA transgenic mice deficient for p53, the addition of any two of the oncogenes c-myc, K-ras, and Akt were sufficient to induce ovarian tumor formation when infected cells were injected at subcutaneous, intraperitoneal, or ovarian sites. We demonstrated that the ovarian surface epithelium is the precursor tissue for these ovarian carcinomas, and that introduction of oncogenes causes phenotypic changes in the ovarian surface epithelial cells. The induced ovarian tumors in mice resembled human ovarian carcinomas in their rapid progression and intraperitoneal metastatic spread. PMID: 12086888 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 268: Cancer Cell. 2002 Apr;1(3):289-98. Dissecting p53 tumor suppressor functions in vivo. Schmitt CA, Fridman JS, Yang M, Baranov E, Hoffman RM, Lowe SW. Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA. Although the p53 tumor suppressor acts in a plethora of processes that influence cellular proliferation and survival, it remains unclear which p53 functions are essential for tumor suppression and, as a consequence, are selected against during tumor development. Using a mouse model harboring primary, genetically modified myc-driven lymphomas, we show that disruption of apoptosis downstream of p53 by Bcl2 or a dominant-negative caspase 9 confers-like p53 loss-a selective advantage, and completely alleviates pressure to inactivate p53 during lymphomagenesis. Despite their p53-null-like aggressive phenotype, apoptosis-defective lymphomas that retain intact p53 genes do not display the checkpoint defects and gross aneuploidy that are characteristic of p53 mutant tumors. Therefore, apoptosis is the only p53 function selected against during lymphoma development, whereas defective cell-cycle checkpoints and aneuploidy are mere byproducts of p53 loss. PMID: 12086865 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 269: Biochim Biophys Acta. 2002 Jul 18;1587(2-3):174-82. Thymidylate synthase as a translational regulator of cellular gene expression. Liu J, Schmitz JC, Lin X, Tai N, Yan W, Farrell M, Bailly M, Chen T, Chu E. Department of Medicine and Pharmacology, Yale Cancer Center, Yale University School of Medicine, USA. Studies from our laboratory have shown that the folate-dependent enzyme, thymidylate synthase (TS), functions as an RNA binding protein. There is evidence that TS, in addition to interacting with its own TS mRNA, forms a ribonucleoprotein complex with a number of other cellular mRNAs, including those corresponding to the p53 tumor suppressor gene and the myc family of transcription factors. Using both in vitro and in vivo model systems, we have demonstrated that the functional consequence of binding of TS protein to its own cognate mRNA, as well as binding of TS to the p53 mRNA, is translational repression. Herein, we review current work on the translational autoregulatory control of TS expression and discuss the molecular elements that are required for the TS protein-TS mRNA interaction. TS may play a critical role in regulating the cell cycle and the process of apoptosis through its regulatory effects on expression of p53 and perhaps other cell cycle related proteins. Finally, the ability of TS to function as a translational regulator may have important consequences with regard to the development of cellular resistance to various anticancer drugs. Publication Types: Review Review, Tutorial PMID: 12084459 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 270: Oncogene. 2002 May 2;21(19):3043-9. p53 mutations and tetraploids under r- and K-selection. Chikatsu N, Nakamura Y, Sato H, Fujita T, Asano S, Motokura T. Department of Internal Medicine, Faculty of Medicine, the University of Tokyo, 3-28-6 Mejirodai, Bunkyo-ku, Tokyo 112-8688, Japan. Cotransfection of rat embryo fibroblasts with c-myc and activated H-ras oncogenes is one experimental model of the multistep oncogenesis associated with p53 mutations and aneuploidy. Using the model, we found that selection processes, e.g., r- and K-selection, affect emergence of p53 mutants and tetraploids. Culture optimum for logarithmic growth (r-selection) selected p53 mutants as they proliferated rapidly, while in confluent culture (K-selection) tetraploids emerged regardless of the p53 status. Transfection of the mutated p53 gene with dominant negative functions eradicated untransfected cells under both r- and K-selection. However, these p53 mutants can be eradicated under K-selection by cells with normal p53 function and that had been selected under prolonged K-selection. The presence of competitors and the type of selection should determine whether or not p53 mutants and/or tetraploids predominate. These observations strengthen the importance of selection processes in case of cancer. PMID: 12082535 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 271: J Cell Sci. 2002 Jul 1;115(Pt 13):2639-50. Hyperproliferation, induction of c-Myc and 14-3-3sigma, but no cell fragility in keratin-10-null mice. Reichelt J, Magin TM. Institute of Physiological Chemistry and Bonner Forum Biomedizin, University of Bonn, Nussallee 11, 53115 Bonn, Germany. In the past, keratins have been established as structural proteins. Indeed, mutations in keratin 10 (K10) and other epidermal keratins lead to severe skin fragility syndromes. Here, we present adult K10-/- mice, which reveal a novel connection between the regulation of cell proliferation and K10. Unlike most keratin mutant mice, the epidermis of adult K10-/- mice showed no cytolysis but displayed hyperproliferation of basal keratinocytes and an increased cell size. BrdU labelling revealed a shortened transition time for keratinocytes migrating outwards and DAPI staining of epidermal sheets uncovered an impaired organization of epidermal proliferation units. These remarkable changes were accompanied by the induction of c-Myc, cyclin D1, 14-3-3sigma and of wound healing keratins K6 and K16. The phosphorylation of Rb remained unaltered. In line with the downregulation of K10 in squamous cell carcinomas and its absence in proliferating cells in vivo, our data suggest that the tissue-restricted expression of some members of the keratin gene family not only serves structural functions. Our results imply that the altered composition of the suprabasal cytoskeleton is able to alter the proliferation state of basal cells through the induction of c-Myc. A previous model based on transfection of K10 in immortalized human keratinocytes suggested a direct involvement of K10 in cell cycle control. While those experiments were performed in human cultured keratinocytes, our data establish, that in vivo, K10 acts by an indirect control mechanism in trans. PMID: 12077355 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 272: Chromosome Res. 2002;10(3):239-51. The impact of p53 loss on murine plasmacytoma development. Mai S, Wiener F. Manitoba Institute of Cell Biology, The Genomic Centre for Cancer Research and Diagnosis, Department of Physiology, The University of Manitoba, Winnipeg, Canada. smai@cc.umanitoba.ca Mouse plasmacytomas (PCTs) are characterized by c-myc-activating translocations that juxtapose c-myc on chromosome 15 onto one of the immunoglobulin loci (IgH on chromosome 12, IgK on chromosome 6, or IgA on chromosome 16). To assess the impact of p53 loss on PCT genesis, we induced PCTs in p53-deficient BALB/cRb6.15 mouse strains. We show that p53 loss accelerates tumor development and causes a shift in the typical translocation patterns. PCTs that carry variant T(6;15) translocations become as frequent as those with typical T(12;15) translocations (41.66%). In addition, in the absence of p53, the number of translocation-negative PCTs increases from less than 1% to 16.66%. It is noteworthy that neither the shortened latency periods nor the shift in translocation patterns had an impact on the incidence of PCT development. The 42.2% incidence in N3p53-/- mice is similar to the percentages recorded in groups of conventional BALB/cAn mice. The possible mechanisms underlying the accelerated tumorigenesis and the shift in translocation patterns are discussed. PMID: 12067213 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 273: Mol Cell. 2002 May;9(5):1031-44. c-Myc can induce DNA damage, increase reactive oxygen species, and mitigate p53 function: a mechanism for oncogene-induced genetic instability. Vafa O, Wade M, Kern S, Beeche M, Pandita TK, Hampton GM, Wahl GM. The Salk Institute for Biological Studies, La Jolla, CA 92037, USA. Oncogene overexpression activates p53 by a mechanism posited to involve uncharacterized hyperproliferative signals. We determined whether such signals produce metabolic perturbations that generate DNA damage, a known p53 inducer. Biochemical, cytological, cell cycle, and global gene expression analyses revealed that brief c-Myc activation can induce DNA damage prior to S phase in normal human fibroblasts. Damage correlated with induction of reactive oxygen species (ROS) without induction of apoptosis. Deregulated c-Myc partially disabled the p53-mediated DNA damage response, enabling cells with damaged genomes to enter the cycle, resulting in poor clonogenic survival. An antioxidant reduced ROS, decreased DNA damage and p53 activation, and improved survival. We propose that oncogene activation can induce DNA damage and override damage controls, thereby accelerating tumor progression via genetic instability. PMID: 12049739 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 274: World J Gastroenterol. 2002 Jun;8(3):385-92. The prognostic molecular markers in hepatocellular carcinoma. Qin LX, Tang ZY. Liver Cancer Institute and Zhongshan Hospital, Fudan university, 136 Yi Xue Yuan Road, Shanghai 200032, China. The prognosis of hepatocellular carcinoma (HCC) still remains dismal, although many advances in its clinical study have been made. It is important for tumor control to identify the factors that predispose patients to death. With new discoveries in cancer biology, the pathological and biological prognostic factors of HCC have been studied quite extensively. Analyzing molecular markers (biomarkers) with prognostic significance is a complementary method. A large number of molecular factors have been shown to associate with the invasiveness of HCC, and have potential prognostic significance. One important aspect is the analysis of molecular markers for the cellular malignancy phenotype. These include alterations in DNA ploidy, cellular proliferation markers (PCNA, Ki-67, Mcm2, MIB1, MIA, and CSE1L/CAS protein), nuclear morphology, the p53 gene and its related molecule MD M2, other cell cycle regulators (cyclin A, cyclin D, cyclin E, cdc2, p27, p73), oncogenes and their receptors (such as ras, c-myc, c-fms, HGF, c-met, and erb-B receptor family members), apoptosis related factors (Fas and FasL), as well as telomerase activity. Another important aspect is the analysis of molecular markers involved in the process of cancer invasion and metastasis. Adhesion molecules (E-cadherin, catenins, serum intercellular adhesion molecule-1, CD44 variants), proteinases involved in the degradation of extracellular matrix (MMP-2, MMP-9, uPA, uPAR, PAI), as well as other molecules have been regarded as biomarkers for the malignant phenotype of HCC, and are related to prognosis and therapeutic outcomes. Tumor angiogenesis is critical to both the growth and metastasis of cancers including HCC, and has drawn much attention in recent years. Many angiogenesis-related markers, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived endothelial cell growth factor (PD-ECGF), thrombospondin (TSP), angiogenin, pleiotrophin, and endostatin (ES) levels, as well as intratumor microvessel density (MVD) have been evaluated and found to be of prognostic significance. Body fluid (particularly blood and urinary) testing for biomarkers is easily accessible and useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum, and its genetic alterations in HCC are other important trends. More attention should be paid to these two areas in future. As the progress of the human genome project advances, so does a clearer understanding of tumor biology, and more and more new prognostic markers with high sensitivity and specificity will be found and used in clinical assays. However, the combination of some items, i.e., the pathological features and some biomarkers mentioned above, seems to be more practical for now. Publication Types: Review PMID: 12046056 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 275: Cancer Res. 2002 Jun 1;62(11):3276-81. Inactivation of E2f1 enhances tumorigenesis in a Myc transgenic model. Rounbehler RJ, Rogers PM, Conti CJ, Johnson DG. Department of Carcinogenesis, Science Park-Research Division, University of Texas M. D. Anderson Cancer Center, Smithville, TX 78957, USA. Previous studies have demonstrated both oncogenic and tumor suppressive properties for the E2F1 transcription factor. In this study, E2f1-null mice were crossed with transgenic mice expressing Myc under the control of an epithelial-specific keratin 5 promoter to determine whether the absence of E2F1 would modulate the oncogenic activity of Myc. Inactivation of E2f1 was found to significantly accelerate tumor development in keratin 5 Myc transgenic mice. Acceleration of tumorigenesis occurred despite the fact that apoptosis levels were increased in transgenic tissue and tumors null for E2f1, whereas Myc-induced proliferation was unaffected by the status of E2f1. These findings provide new insight into the tumor suppressive activity of E2F1 and identify for the first time a specific oncogenic alteration that cooperates with the loss of E2F1 in tumorigenesis. PMID: 12036945 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 276: Blood. 2002 Jun 15;99(12):4554-61. Evidence for distinct pathomechanisms in B-cell chronic lymphocytic leukemia and mantle cell lymphoma by quantitative expression analysis of cell cycle and apoptosis-associated genes. Korz C, Pscherer A, Benner A, Mertens D, Schaffner C, Leupolt E, Dohner H, Stilgenbauer S, Lichter P. Abteilung Molekulare Genetik and Zentrale Einheit Biostatistik, Deutsches Krebsforschungszentrum, Heidelberg, Germany. The B-cell lymphoproliferative malignancies B-cell chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL) share characteristics, including overlapping chromosomal aberrations with deletions on chromosome bands 13q14, 11q23, 17p13, and 6q21 and gains on chromosome bands 3q26, 12q13, and 8q24. To elucidate the biochemical processes involved in the pathogenesis of B-CLL and MCL, we analyzed the expression level of a set of genes that play central roles in apoptotic or cell proliferation pathways and of candidate genes from frequently altered genomic regions, namely ATM, BAX, BCL2, CCND1, CCND3, CDK2, CDK4, CDKN1A, CDKN1B, E2F1, ETV5, MYC, RB1, SELL, TFDP2, TNFSF10, and TP53. Performing real-time quantitative reverse transcription polymerase chain reaction in a panel of patients with MCL and B-CLL and control samples, significant overexpression and underexpression was observed for most of these genes. Statistical analysis of the expression data revealed the combination of CCND1 and CDK4 as the best classifier concerning separation of both lymphoma types. Overexpression in these malignancies suggests ETV5 as a new candidate for a pathogenic factor in B-cell lymphomas. Characteristic deregulation of multiple genes analyzed in this study could be combined in a comprehensive picture of 2 distinctive pathomechanisms in B-CLL and MCL. In B-CLL, the expression parameters are in strong favor of protection of the malignant cells from apoptosis but did not provide evidence for promoting cell cycle. In contrast, in MCL the impairment of apoptosis induction seems to play a minor role, whereas most expression data indicate an enhancement of cell proliferation. PMID: 12036888 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 277: Oncogene. 2002 May 30;21(24):3827-35. Tbx3 impinges on the p53 pathway to suppress apoptosis, facilitate cell transformation and block myogenic differentiation. Carlson H, Ota S, Song Y, Chen Y, Hurlin PJ. Shriners Hospitals for Children, Oregon Health Sciences University, 3101 Sam Jackson Park Road, Portland, OR 97201, USA. Tbx3 is a member of the T-box family of transcription factors. Mutations in Tbx3 cause ulnar-mammary syndrome, an autosomal dominant disorder characterized by upper limb defects, apocrine-gland defects including mammary hypoplasia, and tooth, hair and genital defects. In cell culture, Tbx3 and its close relative Tbx2 are capable of immortalizing mouse embryo fibroblasts. We show that expression of Tbx3 together with Myc or oncogenic Ras (H-Ras(Val17)) leads to efficient transformation of mouse embryo fibroblasts. Oncogene cooperation by Tbx3 correlates with an ability of Tbx3 to suppress the induction of p19ARF and p53 that is typically caused by overexpression Myc and Ras, and to protect against Myc-induced apoptosis. Whereas Tbx3 is capable of interfering with apoptosis caused by excessive Myc levels, a Tbx3 mutant lacking its C-terminal repression domain shows no anti-apoptotic activity and fails to repress levels of p19ARF or p53. Consistent with an ability to suppress p53 pathway function, we find that Tbx3, but not a Tbx3 C-terminal mutant, efficiently blocks myogenic differentiation of C2C12 myoblasts. Our results support the idea that deregulation and/or excessive levels of Tbx3 may have oncogenic potential in vivo. PMID: 12032820 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 278: Biochem Soc Trans. 2002 Apr;30(2):11-7. Role of Src in signal transduction pathways. The Jubilee Lecture. Courtneidge SA. Van Andel Research Institute, 333 Bostwick NE, Grand Rapids, MI 49503, U.S.A. sara.courtneidge@vai.org Src was the first oncogene to be discovered, and the first protein tyrosine kinase. The study of how Src transforms cells has been a rich field that has lead to insights into the control of the cell cycle, the organization of the cytoskeleton, and growth factor-independent growth. Yet we still do not fully understand exactly what Src does. In normal cells, Src has been implicated in the control of cell division, the production of autocrine growth factors, the cell's survival response, as well as in cell motility. My laboratory has focused on the involvement of Src and related kinases in the response of cells to mitogenic growth factors. We have shown that the activity of Src kinases is necessary for cells to enter the cell cycle when treated with mitogens such as platelet-derived growth factor. Src activity initiates a signal transduction cascade, involving the adaptor protein Shc, which culminates in the transcriptional activation of the transcription factor Myc. Furthermore, we have also shown that this requirement for Src is abrogated in cells lacking the tumour suppressor p53, suggesting that another of Src's functions in normal cells is to suppress the actions of p53. Publication Types: Lectures PMID: 12023816 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 279: Anticancer Res. 2002 Jan-Feb;22(1A):225-30. Effect of rancid corn oil on some onco/suppressor gene expressions in vivo. A short-term study. Perjesi P, Pinter Z, Gyongyi Z, Ember I. Department of Medical Chemistry, University Medical School of Pecs, Hungary. Autooxidation of polyunsaturated fatty acids (PUFAs) of edible oils results in the formation of fatty acid hydroperoxides that can undergo further chemical transformations to yield a variety of re-arranged and chain-cleavage products. Since the oxidation products of PUFAs have been reported to have cytotoxic and mutagenic effects, the consumption of rancid oils and fats represents a possible health hazard for the population. Storage of corn oil at room temperature and in the refrigerator for a forty-eight month period resulted in two different qualities of oil samples, which were characterized by UV, titrimetric (peroxide value, acid value) and GC-MS methods. Earlier it was demonstrated that the increase of expression of certain oncogenes and tumor suppressor genes is a method of choice for the early detection of carcinogen exposure. Treatment of CBA/Calpha inbred mice with the two oil samples showed significantly increased expression of the Ha-ras gene in all the investigated organs (liver, lung, kidney, thymus and spleen) of the rancid corn oil-treated animals. Expression of the c-myc and the p53 genes was also increased after the rancid corn oil-treatment in all the organs but the thymus of the mice. The results suggest that rancid oils, rich in omega-6 unsaturated fatty acids, could be involved not only in tumor promotion but in initiation as well. PMID: 12017293 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 280: New Microbiol. 2002 Apr;25(2):195-204. p53 and c-myc activation by Pasteurella haemolytica leukotoxin is correlated with bovine mononuclear cells apoptosis. Marcatili A, D'Isanto M, Vitiello M, Galdiero R, Galdiero M. Dipartimento di Patologia Generale, Facolta di Medicina e Chirurgia, Seconda Universita degli Studi di Napoli, Italy. To analyse the role of Pasteurella haemolytica Leukotoxin (LKT) in the mechanism of apoptotic cell death of bovine lymphocytes, we evaluated DNA fragmentation and p53 and c-myc expression. P. haemolytica strain ATCC 14003 was cultivated for LKT production. DNA fragmentation was analysed by electrophoresis on Agarose gel. DNA strand breaks in individual apoptotic cells were also detected by an in situ Terminal deoxy nucleotidyl Transferase (TdT). The Polymerase Chain Reaction (PCR) procedure was used for verified p53 and c-myc activation by P. haemolytica LKT. LKT was able to induce DNA fragmentation in a dose and time-dependent fashion. The greatest apoptotic effect was obtained using LKT at a concentration of 0.25 U. The results show that p53 and c-myc activation by LKT is correlated with apoptosis of bovine lymphocytes and monocytes. Our data suggest that LKT may have an important role in the bacterial virulence of Pasteurella haemolytica. PMID: 12019726 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 281: Int J Oncol. 2002 Jun;20(6):1151-9. Characterization of novel cell lines established from three human oral squamous cell carcinomas. Lee G, Kim YB, Kim JH, Kim MS, Shin KH, Won YS, Lee JI, Choung PH, Hyun BH, Min BM. Department of Oral Biochemistry, College of Dentistry Seoul National University, Korea. Human oral squamous cell carcinoma cell lines (KOSCC-11, -25A, -25B, -25C, -25D, -25E, -33A, and -33B) were established by explantation culture from these oral squamous cell carcinomas. The histopathology of the primary tumors, in vitro growth characteristics, epithelial origin, in vitro anchorage-independency, in vivo tumorigenicity, the frequency of human papillomavirus (HPV) infections, and the status of proto-oncogenes, tumor suppressor genes, DNA mismatch repair genes, and microsatellite instability were investigated in the cell lines. KOSCC-11 is a well-differentiated oral squamous cell carcinoma (OSCC) derived from mandibular gingiva. KOSCC-25A, -25B, -25C, -25D, and -25E cell lines were derived from the same OSCC. KOSCC-33A and -33B were established from the same tumor that originated from the maxillary sinus. All tumor lines studied grew as monolayers and showed: i) epithelial origin by the presence of desmosome and keratin; ii) in vitro anchorage-independent growth ability; and iii) tumorigenic potential in nude mice. The cancer cell lines did not contain HPV DNA and did not express viral genes. Northern blot analysis revealed: i) overexpression of EGFR in four cell lines, ii) overexpression of c-H-ras in four cell lines, iii) overexpression of c-myc in three cell lines, iv) decreased expression of TGF-alpha in seven cell lines, and v) decreased expression of c-jun in five cancer cell lines compared with normal human oral keratinocytes. In all KOSCC cell lines and their corresponding tumor tissues, mutations were identified in highly-conserved functional regions of the p53 gene. The KOSCC-11 cell line contained a frameshift mutation and the other cell lines harbored an identical p53 mutation at codon 175 from CGC (Arg) to CTC (Leu). In five cell lines, a significant reduction of p21WAF1/Cip1 protein was evident. Cancer cell lines expressed higher level of Rb protein than normal human oral keratinocytes. DCC, a tumor suppressor gene, was not detected in KOSCC-25C. The KOSCC-33A cell line displayed microsatellite instability and showed a loss of hMSH2 expression. These well-characterized human OSCC cell lines should serve as useful tools for understanding the biological characteristics of oral cancer. PMID: 12011992 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 282: Apoptosis. 2002 Jun;7(3):261-70. Death associated protein kinase: from regulation of apoptosis to tumor suppressive functions and B cell malignancies. Ng MH. Hematology Section, Department of Anatomical & Cellular Pathology, CUHK, Prince of Wales Hospital, Shatin, HKSAR, People's Republic of China. margaretng@cuhk.edu.hk Death associated protein kinase (DAP-kinase) is a pro-apoptotic calcium/calmodulin-regulated serine/threonine kinase with a multidomain structure that participates in a wide array of apoptotic systems initiated by IFN-gamma, TNF-alpha, activated Fas, and detachment from extracellular matrix. At various stages during tumor development, cells are subjected to apoptosis inducing stimuli and genetic mutations causing inhibition of apoptosis confer a selective advantage to cells. Thus, apoptosis and its regulation play an important role in tumor initiation, progression and metastasis. It has been demonstrated that the tumor-suppressive properties of DAP-kinase operate at two different apoptotic checkpoints in the course of tumor development; first, during the early oncogene-activated apoptotic checkpoint mediated by p19ARF-p53 pathway and second, during the late stages of metastasizing cells entering the circulation after detachment from extracellular matrix. Promoter hypermethylation of DAP-kinase has been observed in a high variety of primary tumors including head and neck tumors, and non-small cell lung cancers, where an association with poor prognosis was also noted. Notably, high frequencies of DAP-kinase methylation have been found in B cell lymphomas and myeloma, where loss of control of c-Myc induced hyperproliferation from inactivated DAP-kinase may possibly play an important role in the pathogenesis of these B cell neoplasms. Publication Types: Review Review, Tutorial PMID: 11997670 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 283: Biochem J. 2002 Aug 1;365(Pt 3):765-72. Events in the immortalizing process of primary human mammary epithelial cells by the catalytic subunit of human telomerase. Kim H, Farris J, Christman SA, Kong BW, Foster LK, O'Grady SM, Foster DN. Department of Animal Science, University of Minnesota, St. Paul, MN 55108, U.S.A. The in vitro immortalization of primary human mammary epithelial (HME) cells solely by the exogenous introduction of the catalytic subunit of human telomerase (hTERT) has been achieved. Early passage hTERT-transfected HME (T-HME) cells continuously decreased the length and density of telomeres even in the presence of telomerase activity, with a significant number of cells staining positive for senescence-associated beta-galactosidase (SA-beta-gal). Subsequently, with the increase in cell passages, the copy number of the exogenously transfected hTERT gene and the percentage of SA-beta-gal positive cells were found to decrease. Eventually, a single copy of the exogenous hTERT gene was observed in the relatively later passage T-HME cells in which telomere length was elongated and stabilized without obvious activation of endogenous hTERT and c-Myc expression. In T-HME cells, the expression of two p53 regulated genes p21(WAF) and HDM2 increased (as in primary senescent HME cells), and was found to be further elevated as the function of p53 was activated by treatment with DNA-damaging agents. p16(INK4a) was shown to be significantly higher in the primary senescent HME and the early passage T-HME cells when compared with the primary presenescent HME cells, with a dramatic repression of p16(INK4a) observed in the later passage T-HME cells. In addition, the expression of E2F1 and its transcription factor activity were found to be significantly higher in the later passage T-HME cells when compared with the earlier passage T-HME cells. Together, our results indicate that in vitro immortalization in HME cells may require the activation of the function of telomerase and other genetic alterations such as the spontaneous loss of p16(INK4a) expression. PMID: 11978176 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 284: Biochem Pharmacol. 2002 Apr 1;63(7):1251-8. Induction of G(2)/M arrest and inhibition of c-myc and p53 transcription by WP631 in Jurkat T lymphocytes. Villamarin S, Ferrer-Miralles N, Mansilla S, Priebe W, Portugal J. Departamento de Biologia Molecular y Celular, Instituto de Biologia Molecular de Barcelona, CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain. WP631, a new DNA-binding drug that bisintercalates into DNA with high affinity, seems to be highly cytotoxic against Jurkat T lymphocytes. The purpose of this study was to gain new insights into the mechanisms by which WP631 halts proliferation in this cell type. Treating Jurkat cells with nanomolar concentrations of WP631 produced G(2)/M arrest, inhibited the transcription of c-myc and p53 genes, and induced limited apoptosis during the duration of treatment. Suppression of c-myc and p53 expression, and time-dependent decline in c-Myc and p53 protein levels, was associated with growth arrest. A weak interdependence was also found between the potent antiproliferative activity and the apoptotic response; treatment with WP631 for 24-36hr produced arrest in G(2)/M and allowed for partial DNA repair. Longer treatments with WP631 allowed some repaired cells to re-enter the cell cycle, but produced aneuploidy or apoptosis in others. PMID: 11960601 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 285: Lung Cancer. 2002 May;36(2):125-32. Association of L-myc polymorphism with lung cancer susceptibility and prognosis in relation to age-selected controls and stratified cases. Shih CM, Kuo YY, Wang YC, Jian SL, Hsu YT, Wu HY, Guo MW, Wang YC. Department of Internal Medicine, Taichung Veterans General Hospital, Taiwan, ROC. The association of L-myc polymorphism with cancer susceptibility and prognosis has produced conflicting results. This may have been due to racial/ethnic differences and methodological variations in the studies, such as, control selection and case stratification. Therefore, we investigated the genotype distribution of the L-myc polymorphism in 169 lung cancer patients and 169 non-cancer controls, and analyzed the association of this polymorphism with cancer susceptibility and prognosis in relation to age-specific controls as well as stratified cases. The genotype frequencies in the Taiwanese non-cancer controls were 0.56 (L) and 0.44 (S). Chi-square (chi(2)) analysis indicated a significant difference in the Taiwanese genotype distribution of L-myc compared with that of African-Americans (P=0.001). Logistic regression analysis of cases/controls, adjusted for both age and sex, indicated that an increased frequency of the LL genotype was observed in early-staged patients compared with the non-cancer controls (OR=0.43, 95% CI, 0.20-0.94, P=0.03). In addition, the frequency of the LL genotype was significantly higher in stages I+II patients (47.4%) than in stages III+IV patients (28.4%) (P=0.05). Furthermore, the S allele frequency was significantly increased in stages III+IV patients (P=0.005). As both L-myc and p53 polymorphisms were analyzed for their prognostic value, the patients with an S allele of the L-myc gene and a Pro/Pro variant genotype of the p53 gene had significantly poorer prognoses compared with other patients (P=0.004, by the log rank test). These data suggest that the S allele of the L-myc polymorphism may be associated with lung cancer progression. PMID: 11955646 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 286: Br J Cancer. 2002 Apr 8;86(7):1104-9. Dominant negative knockout of p53 abolishes ErbB2-dependent apoptosis and permits growth acceleration in human breast cancer cells. Huang GC, Hobbs S, Walton M, Epstein RJ. Department of Medicine, King's College School of Medicine, Bessemer Rd, London, SW3, UK. We previously reported that the ErbB2 oncoprotein prolongs and amplifies growth factor signalling by impairing ligand-dependent downregulation of hetero-oligomerised epidermal growth factor receptors. Here we show that treatment of A431 cells with different epidermal growth factor receptor ligands can cause growth inhibition to an extent paralleling ErbB2 tyrosine phosphorylation. To determine whether such growth inhibition signifies an interaction between the cell cycle machinery and ErbB2-dependent alterations of cell signalling kinetics, we used MCF7 breast cancer cells (which express wild-type p53) to create transient and stable ErbB2 transfectants (MCF7-B2). Compared with parental cells, MCF7-B2 cells are characterised by upregulation of p53, p21(WAF) and Myc, downregulation of Bcl2, and apoptosis. In contrast, MCF7-B2 cells co-transfected with dominant negative p53 (MCF7-B2/Delta p53) exhibit reduced apoptosis and enhanced growth relative to both parental MCF7-B2 and control cells. These data imply that wild-type p53 limits survival of ErbB2-overexpressing breast cancer cells, and suggest that signals of varying length and/or intensity may evoke different cell outcomes depending upon the integrity of cell cycle control genes. We submit that acquisition of cell cycle control defects may play a permissive role in ErbB2 upregulation, and that the ErbB2 overexpression phenotype may in turn select for the survival of cells with p53 mutations or other tumour suppressor gene defects. PMID: 11953857 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 287: Clin Cancer Res. 2002 Apr;8(4):980-5. p14ARF promoter hypermethylation in plasma DNA as an indicator of disease recurrence in bladder cancer patients. Dominguez G, Carballido J, Silva J, Silva JM, Garcia JM, Menendez J, Provencio M, Espana P, Bonilla F. Department of Medical Oncology, Clinica Puerta de Hierro, E-28035 Madrid, Spain. PURPOSE: Several genes are reported to be implicated in bladder carcinogenesis, including p53, p16INK4a, pRb, erbB-2, Cyclin D1, H-ras, EGFR, and c-myc. Gene alterations in plasma DNA identical to those observed within the tumor have been detected in various types of neoplasia. EXPERIMENTAL DESIGN: We analyzed loss of heterozygosity in six microsatellite markers (D17S695, D17S654, D13S310, TH2, D9S747, and D9S161), p53 and K-ras mutations, and the promoter status of p14ARF and p16INK4a in the mononuclear normal blood cells, tumor, and plasma DNA of 27 bladder cancer patients. We also studied the distribution of several clinicopathological parameters in these patients in regard to molecular alterations. RESULTS: Seventeen (63%) cases displayed the same alteration in plasma and tumor DNA (some patients showed more than one alteration simultaneously). Plasma p14ARF promoter hypermethylation was associated with the presence of multicentric foci (P = 0.03), larger tumors (P = 0.01), and relapse of the disease (P = 0.03). Plasma loss of heterozygosity was also linked to disease recurrence (P = 0.02). CONCLUSIONS: The results indicate that p14ARF aberrant promoter methylation could be involved in bladder carcinogenesis and that plasma DNA is a potential prognostic marker in urinary bladder cancer. PMID: 11948103 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 288: Environ Mol Mutagen. 2002;39(2-3):171-7. Tumor formation in Brca1 conditional mutant mice. Deng CX. Genetics of Development and Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. chuxiad@bdg10.niddk.nih.gov BRCA1 is the first breast cancer-associated gene, whose mutation predisposes women to breast and ovarian cancers. Targeted mutations of Brca1 in the mouse result in embryonic lethality primarily attributed to cellular proliferation defects, raising questions about the mechanisms by which Brca1 represses tumor formation. To overcome the early lethality, we engineered Brca1 by flanking its exon 11 with loxP sites. We showed that deletion of the exon by EIIA-Cre, which expresses Cre in the germline, causes p53-dependent lethality at late gestation. On the other hand, MMTV-Cre, which expresses Cre in mammary epithelium, resulted in tumorigenesis at low frequency after a long latency, accompanied by increased epithelial cell apoptosis and abnormal ductal development. Mammary tumor formation was significantly accelerated in a p53(+/-) genetic background; however, it still appeared in a stochastic fashion, suggesting the involvement of additional factors. Notably, the tumors were highly diverse in histopathology and displayed extensive genetic/molecular alterations, including overexpression of ErbB2, c-Myc, p27, and Cyclin D1, and downregulation of p16 in the majority of tumors. This observation suggests roles for these proteins in Brca1-associated tumorigenesis. Publication Types: Review Review, Tutorial PMID: 11921186 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 289: J Pathol. 2002 Apr;196(4):408-15. Quantitative expansion of structural genomic alterations in the spectrum of neuroendocrine lung carcinomas. Gugger M, Burckhardt E, Kappeler A, Hirsiger H, Laissue JA, Mazzucchelli L. Institute of Pathology, University of Bern, Bern, Switzerland. The pathogenesis and interrelationships of neuroendocrine lung carcinomas are not well understood. Tissue macro-arrays prepared from surgical resection specimens from 35 patients with typical carcinoid (TC), six with atypical carcinoid (AC), 13 with large cell neuroendocrine carcinoma (LCNEC), and 15 with small cell lung carcinoma (SCLC) were investigated by fluorescence in situ hybridization (FISH) and immunohistochemistry. Hybridizations with locus-specific DNA probes demonstrated a high incidence of deletion for the tumour suppressor genes p53 and retinoblastoma (Rb), and for the oncogene cyclin D1, comparable in all carcinoma types. Similarly, an increase of DNA copy number for the Her-2/neu and c-myc oncogenes was noted in all neoplasms. A more detailed quantitative analysis of the results, however, demonstrated increasing numbers of cells harbouring these genomic alterations, from low-grade TC to highly malignant SCLC, with the exception of cyclin D1 deletion. Mutations of the p53 and Rb genes, as assayed by immunohistochemical studies, were observed at high incidence in high-grade carcinomas, compared with a low incidence in the low-grade carcinomas. Conversely, in all carcinoma types, neither membrane-bound Her-2/neu nor nuclear cyclin D1 was detected. It is concluded that structural genomic alterations are frequent in neuroendocrine lung carcinomas and that their occurrence may be underestimated by immunohistochemical studies alone. The quantitative expansion of the Rb, p53, c-myc, and Her-2/neu alterations towards high-grade carcinomas suggests common pathogenetic mechanisms in the spectrum of these neoplasms. Copyright 2002 John Wiley & Sons, Ltd. PMID: 11920736 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 290: Hematol J. 2001;2(4):234-41. Identification of two subgroups of mantle cell leukemia with distinct clinical and biological features. Vizcarra E, Martinez-Climent JA, Benet I, Marugan I, Terol MJ, Prosper F, Marco J, Sanchez D, Ferrandez A, Tormo M, Sarsotti E, Ferrer R, Garcia M, Ortuno F, Montagud M, Garcia-Conde J. Department of Hematology and Medical Oncology, Hospital Clinico, University of Valencia, Spain. INTRODUCTION: Mantle cell leukemia (MCLeu) has been considered as a leukemic form of mantle cell lymphoma (MCL). However, the presence of certain features rarely observed in MCL, such as transformation to prolymphocytic leukemia (PLL) or indolent clinical course, suggests that MCLeu may represent a distinct disorder. METHODS: Seven cases of MCLeu with t(11;14)(q13;q32) and BCL1-IGH gene rearrangement were ascertained among 140 newly diagnosed chronic B-cell lymphoproliferative disorders with leukemic expression. Comparative genomic hybridization, FISH for specific gene loci, and immunological studies were preformed in them. RESULTS: In comparison with CLL, MCLeu cases had low immunological scores < or =2 with respect to B-CLL (P<0.0001). Expression of CD38 was absent in 43% of MCLeu and in 44% of B-CLL. Comparative genomic hybridization analysis identified genomic imbalances in 86% of MCLeu with a similar pattern than in MCL: gains of 3q, 8q involving MYC gene and 15q, and losses of 6q, 9p, 13q and 17p affecting P53 gene. Differently from MCL and CLL, genomic loss of 8p was frequently detected in MCLeu (83%). Although clinical presentation of MCLeu was indistinguishable from CLL, all patients but one had disease progression within three years. According to the immunologic and genomic profiles, two distinct subgroups of MCLeu were defined: one related to PLL, showing CD38-, deletion of P53, and MYC amplification and another which corresponds to a leukemic form of classical MCL, presenting with CD38+ and normal P53 and MYC status. CONCLUSION: MCLeu and MCL are closely related disorders, as they show similar genomic and molecular patterns. However, the deletion of the short arm of chromosome 8 may represent a specific marker for MCLeu. Two distinct subgroups of MCLeu may also be distinguished according to the immunologic and genomic cell profiles. PMID: 11920255 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 291: Anticancer Res. 2001 Nov-Dec;21(6A):3937-40. Long-term effects of 1-nitropyrene on oncogene and tumor suppressor gene expression. Gyongyi Z, Nadasi E, Varga C, Kiss I, Ember I. Department of Preventive Medicine, Faculty of Medicine, University of Pecs, Hungary. zoli@pubhealth.pote.hu Late changes in the expression of oncogenes and tumor suppressor genes following carcinogenic exposure were examined in lung, liver and kidney. 1-Nitropyrene (1-NP), which is a high-risk exposure factor in urban and industrial zones, was used as a carcinogenic agent. c-myc, Ha-ras and p53 gene expression was investigated after administration of a single dose of 1-NP to sensitive CBA/Ca mice in lung, liver and kidney for one year. One week after a single dose 1-NP administration, the expression of p53 was elevated in the liver, but, decreased in the lung and kidney. There was no increase in the expression of c-myc or Ha-ras genes at that time. One month after the administration of the 1-NP, the expression of p53 was increased in the kidney while the expression of Ha-ras and p53 was elevated in the liver. There was no significant difference in gene expression between the treated and control animal groups at any of the investigated periods except for the above-mentioned organs and at the end point of the investigation. According to the literature, 1-NP and its metabolites remain at high concentrations in the kidney, liver and lung. The concentration of the carcinogenic agent and the expression of the studied genes did not seem to correlate with each other in this experiment. PMID: 11911274 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 292: Gastroenterol Clin Biol. 2001 Dec;25(12):1067-77. [Genetic alterations in hepatocellular carcinomas: associations with clinical parameters] [Article in French] Bluteau O, Laurent-Puig P, Zucman-Rossi J. Unite INSERM U434, Paris. Publication Types: Review Review, Tutorial PMID: 11910987 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 293: J Oral Pathol Med. 2002 Mar;31(3):125-33. The unexplained survival of cells in oral cancer: what is the role of p53? Whyte DA, Broton CE, Shillitoe EJ. whyted@upstate.edu In normal oral epithelium the cells divide, mature, differentiate, and die. This sequence is not normally followed in oral cancer. Instead, the death of the cells is somehow prevented, although the pathways toward cell death in normal oral epithelium and the defects in oral cancer are not well defined. However, several components in the system have been identified, and information on their interactions is becoming available. This review summarizes the evidence for cell death being due to apoptosis and the central role of the p53 gene product in its regulation. Areas for future research are also identified. Publication Types: Review Review, Tutorial PMID: 11903817 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 294: Histopathology. 2001 Dec;39(6):629-37. Secondary malignant giant-cell tumour of bone: molecular abnormalities of p53 and H-ras gene correlated with malignant transformation. Oda Y, Sakamoto A, Saito T, Matsuda S, Tanaka K, Iwamoto Y, Tsuneyoshi M. Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. AIMS: We report two cases of secondary malignant giant-cell tumour occurring without irradiation therapy. To elucidate the mechanism of malignant transformation in this tumour, we searched for the molecular abnormalities of p53, MDM2 and the H-ras genes. METHODS AND RESULTS: These cases were retrieved after a review of 103 cases of primary giant-cell tumour of bone, registered in our institute. One case occurred in the distal femur of a 42-year-old female after surgical curettage, while the other arose in the acetabulum of a 25-year-old male after en bloc resection. Microscopically, the malignant tumour in the distal femur was composed of a proliferation of ovoid or fusiform cells arranged in fascicles with high mitotic activities. The malignant transformed tumour in the acetabulum was made up of pleomorphic tumour cells with atypical mitoses. In the tumour of the distal femur, both p53 and H-ras mutations were detected. Abnormal nuclear accumulation of p53 protein and c-myc expression were also revealed by immunohistochemistry. In both cases, the recurrent malignant tumour over-expressed MMP-9 and revealed a higher MIB-1-labelling index compared with the primary conventional giant-cell tumour. CONCLUSIONS: Our results suggest that multiple oncogene or tumour suppressor gene mutations may play an important role during malignant transformation in conventional giant-cell tumours. Publication Types: Case Reports Review Review of Reported Cases PMID: 11903582 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 295: Oncogene. 2002 Mar 14;21(12):1922-7. A non-transgenic mouse model for B-cell lymphoma: in vivo infection of p53-null bone marrow progenitors by a Myc retrovirus is sufficient for tumorigenesis. Yu D, Thomas-Tikhonenko A. Department of Pathobiology, University of Pennsylvania, Philadelphia, Pennsylvania, PA 19104-6051, USA. The c-Myc oncoprotein is strongly implicated in B-cell neoplasms such as human Burkitt lymphomas and mouse plasmocytomas. Transgenic mice in which the myc gene is juxtaposed to an immunoglobulin enhancer (E(mu)-myc) also develop B-cell lymphomas, but relatively late in life. In addition, these neoplasms are invariably clonal, suggesting the involvement of additional mutations. Such mutations frequently affect the p53 tumour suppressor gene or its positive regulator Arf, hinting that inactivation of the p53 pathway might be the second hit required for the progression towards malignancy. However, even tumours arising in E(mu)-myc/Arf-null animals are thought to be clonal. This observation raised doubts whether overexpression of Myc in p53-null B-cell precursors is sufficient for tumorigenesis. To address this question, we have established a new, non-transgenic mouse model of B-lymphoma. This model is based on isolation of primary bone marrow (BM) cells, admixing them with packaging cells producing a Myc-encoding retrovirus (LMycSN), and subcutaneous injection into a host with which BM cells are syngeneic. Predictably, wild type BM cells infected in vivo by LMycSN were not tumorigenic. However, LMycSN-infected p53-null BM cells readily gave rise to B-cell lymphomas composed predominantly of late pro-B/small pre-B-cells. In these tumours, heavy chain gene rearrangements were analysed using two independent PCR-based assays. All neoplasms with DJ-rearrangements were found to be polyclonal. This result suggests that inactivation of p53 and overexpression of Myc is all that is necessary for the development of full-fledged B-lymphomas. Our model would also be instrumental in assessing the transforming potential of Myc mutants and in studying cooperation between Myc and other oncogenes. PMID: 11896625 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 296: Oncogene. 2002 Mar 14;21(12):1848-58. Caspase-9 and Apaf-1 are expressed and functionally active in human neuroblastoma tumor cell lines with 1p36 LOH and amplified MYCN. Teitz T, Wei T, Liu D, Valentine V, Valentine M, Grenet J, Lahti JM, Kidd VJ. Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, TN 38105, USA. Important roles have been suggested for caspase-8, caspase-9 and Apaf-1 in controlling tumor development and their sensitivity to chemotherapeutic agents. Methylation and deletion of Apaf-1 and CASP8 results in the loss of their expression in melanoma and neuroblastoma, respectively, while CASP9 localization to 1p36.1 suggests it is a good candidate tumor suppressor. The status of CASP9 and Apaf-1 expression in numerous neuroblastoma cell lines with/without amplified MYCN and chromosome 1p36 loss-of-heterozygosity (LOH) was therefore examined to test the hypothesis that one or both of these genes are tumor suppressors in neuroblastoma. Although CASP9 is included in the region encompassing 1p36 LOH in all neuroblastoma cell lines examined, the remaining CASP9 allele(s) express a functional caspase-9 enzyme. Apaf-1 is also expressed in all neuroblastoma tumor cell lines examined. Thus, the CASP9 or Apaf-1 genes do not appear to function as tumor suppressors in MYCN amplified neuroblastomas. However, approximately 20% of the neuroblastoma cell lines with methylated CASP8 alleles are also highly resistant to staurosporine (STS)- and radiation-induced cell death, presumably because cytochrome c is not released from mitochondria. This suggests that a second, smaller sub-group of MYCN amplified neuroblastoma tumors exists with defect(s) in apoptotic signaling components upstream of caspase-9 and Apaf-1. Since no consistent differences in Bcl-2, Bcl-x(L) or Bax expression were seen in the STS- and radiation-resistant neuroblastomas, it suggests that a unique mitochondrial signaling factor(s) is responsible for the defect in cytochrome c release in this sub-group of tumors. PMID: 11896617 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 297: Lab Invest. 2002 Mar;82(3):257-64. Gene mutations in lymphoproliferative disorders of T and NK/T cell phenotypes developing in renal transplant patients. Hoshida Y, Hongyo T, Nakatsuka S, Nishiu M, Takakuwa T, Tomita Y, Nomura T, Aozasa K. Department of Pathology, Osaka University Medical School, Suita, Osaka, Japan. Post-transplantation lymphoproliferative disorder (PT-LPD) is characterized by lymphoid proliferation after organ or bone marrow transplantation. In Western countries, most cases of PT-LPD are B-cell-derived and Epstein-Barr virus-associated, in which alterations of c-myc, p53, and N-ras genes might play a role in disease progression. In Japan, PT-LPD of T- and NK/T-cell types are not uncommon in renal transplant patients. Mutations of p53 (exons 4 through 8), K-ras (exons 1 and 2), c-kit (exons 11 and 17), and beta-catenin genes (exon 3) in 12 cases of these diseases were analyzed by PCR single strand conformation polymorphism and then by direct sequencing. p53 gene mutations were detected in 5 of 5 cases of peripheral T-cell lymphoma, 3 (60%) of 5 cases of adult T-cell leukemia/lymphoma, and 1 of 2 cases of NK/T cell lymphoma. Twenty-five percent of T and NK/T cell lymphomas showed K-ras mutations. Mutations of c-kit and beta-catenin genes were found in 33% of cases. Among a total of 42 substitution mutations, 40 were transitions with involvement of CpG sites in 20 to 30% of cases. Most cases had at least one mutation that changed an amino acid, which might have provided the selection pressure for expansion. These findings suggested that p53 gene mutations might play a central role in development of peripheral T-cell lymphoma including adult T-cell leukemia/lymphoma in renal transplant patients. PMID: 11896204 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 298: Cancer Res. 2002 Mar 1;62(5):1443-9. Transformed and tumor-derived human cells exhibit preferential sensitivity to the thiol antioxidants, N-acetyl cysteine and penicillamine. Havre PA, O'Reilly S, McCormick JJ, Brash DE. Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520-8040, USA. Thiol antioxidants, typified by N-acetyl cysteine, are known to induce p53-dependent apoptosis in transformed mouse embryo fibroblasts but not in normal mouse embryo fibroblasts. We now report that this is also the case for human cells. First, we used an isogenic fibroblast cell lineage exhibiting progressive stages of transformation, from primary derived cells to v-MYC immortalized to tumorigenic. At the immortalization stage, cells became 12- and 480-fold more sensitive to the thiol antioxidants N-acetyl cysteine (NAC) and penicillamine (PEN), respectively. Although immortalization of these cells was associated with v-MYC expression, overexpression of MYC was not sufficient for sensitizing these cells to antioxidants. To test whether sensitivity to antioxidants is a general property of immortalized human cells, including fully transformed cells, 12 tumor-derived cell lines were treated with PEN, the more potent of the two antioxidants. Ten of 11 caspase-proficient tumor cell lines underwent apoptosis after treatment, whereas primary fibroblasts and keratinocytes were resistant. The difference between normal and transformed cells was apparent whether the assay used measured caspase 3 activation, Annexin V binding, or cell viability. Tumor cell lines containing wild-type p53 were more sensitive than p53-null cell lines. The requirement for p53 was tested using the p53 inhibitor, pifithrin-alpha, or using stable transfectants of a v-MYC-immortalized, telomerase-positive cell line that expresses HPV16 E6 to bind and degrade p53. In the latter case, > or = 80% of the PEN-induced apoptosis was dependent on the presence of wild-type p53. These studies suggest that treatment with thiol-containing antioxidants, such as PEN, may offer a useful approach for preferential induction of apoptosis in preneoplastic and neoplastic cells. PMID: 11888918 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 299: Zhonghua Xue Ye Xue Za Zhi. 2000 Jan;21(1):23-6. [Acute promyelocytic leukemia cell differentiation induced by tanshinone II A and its molecular mechanism] [Article in Chinese] Liang Y, Yang Y, Yuan S, Meng W, Liu T, Jia Y. Department of Hematology, First Affiliated Hospital of West China University of Medical Sciences, Chengdu 610041, China. OBJECTIVE: To investigate APL cell differentiation induced by tanshinone II (Tan II A) and its molecular mechanism. METHODS: In vitro incubation of NB4 cells with Tan II A at the concentration of 0.5 microg/ml for 5 days, the cell differentiation was observed by cytomorphology, and nitroblue tetrazolium (NBT) test. Cell cycle, membrane CD(33), CD(11b) antigens and gene expressions (c-myc, c-fos, p53 and bcl-2) were analysed by flow cytometry. RESULTS: (91.3 +/- 2.1)% of NB4 cells were induced into morphologically and functionally more differentiated cells including 0.26 of myelocytes and metamyelocytes, and 0.68 of band form and neutrophils. Cell growth curve showed that growth of NB4 cells were inhibited. NBT reduction was significantly increased. Expression of CD(33) decreased and CD(11b) increased. The degrees of cell differentiation and growth inhibition induced by Tan II A or ATRA were no difference. Flow cytometry analysis showed that Tan II A arrested NB4 cell in G(0)/G(1) phase, inhibited cellular DNA synthesis, down-regulated c-myc and bcl-2 genes expression, and up-regulated c-fos and p53 genes expression. CONCLUSION: Tan II A can induce differentiation and growth inhibition of NB4 cells. Its possible molecular mechanism might relate to modulation of gene expressions associated proliferation and differentiation, and to inhibition of DNA synthesis. PMID: 11876956 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 300: J Biol Chem. 2002 May 10;277(19):16547-52. Epub 2002 Feb 25. The course of etoposide-induced apoptosis from damage to DNA and p53 activation to mitochondrial release of cytochrome c. Karpinich NO, Tafani M, Rothman RJ, Russo MA, Farber JL. Department of Pathology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA. Treatment of L929 fibroblasts by the topoisomerase II inhibitor etoposide killed 50% of the cells within 72 h. The cell killing was preceded by the release of cytochrome c from the mitochondria. Simultaneous treatment of the cells with wortmannin, cycloheximide, furosemide, cyclosporin A, or decylubiquinone prevented the release of cytochrome c and significantly reduced the loss of viability. Etoposide caused the phosphorylation of p53 within 6 h, an effect prevented by wortmannin, an inhibitor of DNA-dependent protein kinase (DNA-PK). The activation of p53 by etoposide resulted in the up-regulation of the pro-apoptotic protein Bax, a result that was prevented by the protein synthesis inhibitor cycloheximide. The increase in the content of Bax was followed by the translocation of this protein from the cytosol to the mitochondria, an event that was inhibited by furosemide, a chloride channel inhibitor. Stably transfected L929 fibroblasts that overexpress Akt were resistant to etoposide and did not translocate Bax to the mitochondria or release cytochrome c. Bax levels in these transfected cells were comparable with the wild-type cells. The release of cytochrome c upon translocation of Bax has been attributed to induction of the mitochondrial permeability transition (MPT). Cyclosporin A and decylubiquinone, inhibitors of MPT, prevented the release of cytochrome c without affecting Bax translocation. These data define a sequence of biochemical events that mediates the apoptosis induced by etoposide. This cascade proceeds by coupling DNA damage to p53 phosphorylation through the action of DNA-PK. The activation of p53 increases Bax synthesis. The translocation of Bax to the mitochondria induces the MPT, the event that releases cytochrome c and culminates in the death of the cells. PMID: 11864976 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 301: Cancer Res. 2002 Feb 15;62(4):1222-30. The RING domain of Mdm2 can inhibit cell proliferation. Dang J, Kuo ML, Eischen CM, Stepanova L, Sherr CJ, Roussel MF. Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. Mdm2 is a p53-inducible phosphoprotein that negatively regulates p53 by binding to it and promoting its ubiquitin-mediated degradation. Alternatively spliced variants of Mdm2 have been isolated from human and mouse tumors, but their roles in tumorigenesis, if any, remain elusive. We cloned six alternatively spliced variants of Mdm2 from E(mu)-Myc-induced mouse lymphomas, all of which lacked the NH(2)-terminal p53-binding domain but conserved the remainder of the Mdm2 protein. Enforced expression of full-length Mdm2 in primary mouse embryo fibroblasts or bone marrow-derived, interleukin 7-dependent pre-B cells accelerated their proliferation, whereas unexpectedly, overexpression of truncated Mdm2 isoforms inhibited their growth. Truncated variants were active as inhibitors whether they localized predominantly to the nucleus or cytoplasm. Despite the absence of the p53-binding domain, growth inhibition remained strictly p53 dependent (but not p19(Arf) dependent) and could be overcome by full-length Mdm2. The intact RING finger domain at the Mdm2 COOH terminus (amino acids 399-489) was necessary and sufficient for growth inhibition by truncated Mdm2 proteins and could physically interact with either the RING finger domain or central acidic region of full-length Mdm2. However, such interactions do not inhibit Mdm2 E3 ubiquitin ligase activity in vitro using p53 as a substrate. Expression of growth-inhibitory Mdm2 isoforms in tumors remains an enigma. PMID: 11861407 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 302: Zhonghua Zhong Liu Za Zhi. 2001 Nov;23(6):441-3. [Mechanism of multidrug resistance caused by retinoic acid] [Article in Chinese] Li C, Fu J. Childrens' Hospital, Shenzhen 518026, China. OBJECTIVE: To investigate the regulatory mechanism of multidrug resistance(MDR) caused by all-trans retinoic acid (ATRA). METHODS: ATRA and IL-4 were used to treat human hepatoblastoma cell line (HepG2) cells. The proliferative activity, synthesis of alpha fetal protein (AFP), and cell cycle distribution of tumor cells were observed to evaluate the degree of cell differentiation. Flow cytometry and in situ hybridization were used to determine the expressing levels of p53, bcl-2, P-glycoprotein (P-gp) and c-jun and c-myc mRNA. MTT assay was used to evaluate the sensitivity of the tumor cells to chemotherapeutic agents. RESULTS: Both ATRA and IL-4 could induce the differentiation of HepG2 cells. ATRA treatment of the tumor cells led to drug resistance in chemotherapy (resistant factors: 1.6-3.1), and IL-4 increased the sensitivity of the tumor cells to antineoplasic drugs (reversal index: 4-17). The level of P-gp expression in ATRA-treated cells was increased from 54.2% +/- 8.6% up to 98.5% +/- 1.4% (P < 0.01), but IL-4 markedly inhibited expression of P-gp down to 25.4% +/- 7.3% (P < 0.01). Both ATRA and IL-4 treatment could down-regulate c-jun and c-myc mRAN expressions. The level of p53 and bcl-2 expression could be up- or down-regulated by IL-4 treatment but they were unaffected by ATRA treatment. CONCLUSION: Degree of cell differentiation and level of c-jun and c-myc mRNA expression might not be related to change in drug sensitivity by inducing differentiation of HepG2 cells with ATRA and IL-4. Increased expression of P-gp caused by ATRA might be one of the factors up-regulating MDR. p53 (or bcl-2) might be involved in regulating the sensitivity of antineoplastic drugs by inducing differentiation. PMID: 11859704 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 303: Int J Cancer. 2002 Feb 20;97(6):732-9. Human papillomavirus type 16 E6-enhanced susceptibility to apoptosis induced by TNF in A2780 human ovarian cancer cell line. Vikhanskaya F, Falugi C, Valente P, Russo P. Molecular Pathology Section, Laboratory of Experimental Oncology, National Institute for Research on Cancer, Genoa, Italy. In our study, we show that expression of HPV-16 E6 sensitizes TNF-induced cytotoxicity of human ovarian cancer cell line A2780. This effect is not related to a different number of TNF receptors present on cell membrane. The major induction of massive apoptosis induced by TNF is not p53- and p21(waf-1)-dependent but it is principally related to NF-kappaB inhibition in A2780/E6 cells. Consistently to NF-kappaB inhibition a rapidly release of cytochrome c and severe induction of DNA fragmentation are seen in A2780/E6 cells. Also in human colon cancer cell line HCT-116/E6 the expression of HPV-16 E6 enhances TNF-cytotoxicity. This effect is not present in the HCT-116/mu-p53 clone (transfected with a dominant-negative mutated p53 transgene). Thus, taken together all these observations suggest that HPV-16 E6 sensitizes A2780 and HCT-116 cells to TNF; this effect is not p53-dependent, but it is essentially mediated through an inhibition in activating NF-kappaB activities. Copyright 2001 Wiley-Liss, Inc. PMID: 11857347 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 304: Cancer Lett. 2002 Apr 8;178(1):53-62. Protective effect of L-carnosine against 12-O-tetradecanoylphorbol-13-acetate- or hydrogen peroxide-induced apoptosis on v-myc transformed rat liver epithelial cells. Kang KS, Yun JW, Lee YS. Department of Veterinary Public Health, College of Veterinary Medicine and School of Agricultural Biotechnology, Seoul National University, 103 Seodun-dong, Kwonsun-ku, Suwon 441-744, South Korea. Apoptotic processes have been associated with cancer and neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease etc. beta-Alanyl-L-histidine (L-carnosine), occurring abundantly in skeletal muscles has been suggested to possess antioxidative activity. We investigated whether L-carnosine prevents 12-O-tetradecanoylphorbol-13-acetate (TPA)- or hydrogen peroxide (H2O2)-induced apoptosis involving mitochondria in the v-myc transformed rat liver epithelial cells (WB-myc cells). L-Carnosine prevented both TPA- and H2O2-induced DNA fragmentation, the loss of mitochondrial membrane potentials and blocked the release of cytochrome c into cytosol. Subsequently, the cleavages of poly (ADP-ribose) polymerase were significantly reduced in L-carnosine-treated cells. However, western blotting analysis revealed that p53 protein level did not change for 12h after TPA- and H2O2-treatment. Therefore, these results suggested that L-carnosine, an antioxidant, protected both H2O2- and TPA-induced apoptosis through mitochondrial pathways. PMID: 11849741 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 305: Anticancer Res. 2001 Sep-Oct;21(5):3377-80. Changes in expression of onco- and suppressor genes in peripheral leukocytes--as potential biomarkers of chemical carcinogenesis. Gyongyi Z, Ember I, Kiss I, Varga C. Department of Preventive Medicine, Faculty of Medicine, University of Pecs, Hungary. zo1i@pubhealth.pote.hu An animal model was developed to investigate the expression of two oncogenes (c-myc, Ha-ras) and a suppressor gene (p53) as early markers of the effects of carcinogenic exposure and/or tumourigenesis. Inbred Long-Evans rats were treated with 7,12-dimethylbenz(a)anthracene and the transient/permanent gene expressions were measured after 24 and 48 hours by dot blotting in potential target tissues (lung, liver, lymph nodes, kidneys, spleen) and in peripheral blood leukocytes. The aim of the study was to test blood leukocytes, as surrogate tissue, showed similar expression patterns of the selected genes following carcinogenic exposure. c-myc did not prove to be an applicable early biomarker due to the lack of or low level of its expression. However, remarkable of early elevations were detected in the expression signals of Ha-ras and p53. PMID: 11848497 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 306: Anticancer Res. 2001 Sep-Oct;21(5):3167-73. Chromosome 8 numerical aberration and C-MYC copy number gain in bladder cancer are linked to stage and grade. Mahdy E, Pan Y, Wang N, Malmstrom PU, Ekman P, Bergerheim U. Department of Urology, Karolinska Hospital, Stockholm, Sweden. Ensaf.Mahdy@kirurgi.ki.se Chromosome 8 aberration and c-myc amplification have been suggested as playing important roles in the development of different human cancers. Using fluorescence in situ hybridization (FISH), chromosome 8 polysomy and c-myc amplification can be detected in cells from bladder cancer. We investigated the correlation of chromosome 8 polysomy, c-myc gene alteration and p53 deletion with histopathological parameters. Twenty-four tumors obtained from patients with bladder cancer were analyzed by interphase cytogenetics using FISH with chromosome 8 and 17 centromere probes together with an YAC clone covering the c-myc locus and three cosmid DNA probes covering the p53 locus. Chromosome 8 polysomy was found in 12 tumors. The average copy number of chromosome 8 centromere signals were significantly higher in high grade and stage, cancers. Also the c-myc copy gain and p53 deletion were significantly correlated with grade as well as stage (p<0.05, in both cases). Both polysomy 8 and c-myc copy gain were significantly correlated with p53 deletions (p<0.01) and DNA ploidy (p<0.001). On the contrary there was no significant correlation between c-myc protein over-expression and c-myc gene amplification. These results may indicate that alteration of chromosomal regions on 8q and 17p, including c-myc and p53 genes, may be linked to progression of bladder cancer. PMID: 11848469 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 307: Leukemia. 2002 Feb;16(2):276-83. Establishment and comprehensive analysis of a new human transformed follicular lymphoma B cell line, Tat-1. Denyssevych T, Lestou VS, Knesevich S, Robichaud M, Salski C, Tan R, Gascoyne RD, Horsman DE, Mayer LD. Department of Advanced Therapeutics, Vancouver Cancer Centre, British Columbia Cancer Agency, and the University of British Columbia, Vancouver, BC, Canada. A spontaneously EBV transformed follicular lymphoma (FL) cell line, Tat-1, was established from the lymph node biopsy specimen of a patient with B cell FL, grade 1 in transformation to high grade disease. Tat-1 cells expressed lymphoid markers and developed tumor masses in immunodeficient mice. Bcl-2, Bcl-X(L), Bax and p53 protein expression was revealed by Western blotting. Flow cytometric analysis confirmed P-gp expression. Cytogenetically, the Tat-1 cell line showed identical chromosomal alterations to that of the initial biopsy specimen, among which the most notable were the t(14;18) typical of FL and additional abnormalities involving chromosomes 1, 8 and 13. Multicolor FISH analysis delineated all abnormalities, including a t(1p;8q), a der(8)(8q24::14q32::18q21) and a der(13)(13q32::8q24::14q32::18q21). Further FISH investigations using a locus-specific probe cocktail containing c-myc, IgH and bcl-2 revealed fusion of these three loci on the derivatives 8 and 13, in addition to the derivative 14 IgH/bcl-2 fusion and an extra copy of c-myc on derivative chromosome 1. These results demonstrate an additional example of the deregulation of bcl-2 and c-myc expression through recombination with a single IgH enhancer region. The unusual molecular features of the Tat-1 cell line render it a unique tool for studies focused on cytogenetic alterations, expression of multidrug resistance phenotype and expression of anti-apoptotic proteins in FL. Publication Types: Case Reports PMID: 11840295 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 308: Mol Cell Biol. 2002 Mar;22(5):1360-8. ARF differentially modulates apoptosis induced by E2F1 and Myc. Russell JL, Powers JT, Rounbehler RJ, Rogers PM, Conti CJ, Johnson DG. Department of Carcinogenesis, Science Park-Research Division, University of Texas M. D. Anderson Cancer Center, Smithville, Texas 78957, USA. The ARF tumor suppressor participates in a p53-dependent apoptotic pathway that is stimulated in response to some oncogenic stimuli. The E2F1 transcription factor is a critical downstream target of the Rb tumor suppressor and, when active, can promote proliferation as well as apoptosis. The finding that E2F1 transcriptionally regulates the ARF gene has led to the suggestion that ARF contributes to E2F1-induced apoptosis. Counter to this hypothesis, this study demonstrates not only that ARF is unnecessary for E2F1 to induce apoptosis but also that inactivation of ARF actually enhances the ability of E2F1 to promote apoptosis. Inactivation of ARF also cooperates with E2F1 activity to promote entry into the S phase of the cell cycle. This relationship between ARF and E2F1 is demonstrated in transgenic epidermis in vivo and in mouse embryo fibroblast cultures in vitro. In contrast, the ability of Myc to induce apoptosis is diminished in the absence of ARF. E2F1 induces the accumulation of p53 in the absence of ARF, and this is associated with the phosphorylation of p53 on several residues. These findings demonstrate that ARF is a negative regulator of E2F1 activity and is not required for E2F1-induced apoptosis. PMID: 11839803 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 309: Dig Dis Sci. 2002 Jan;47(1):107-13. Helicobacter pylori infection and oncogene expressions in gastric carcinoma and its precursor lesions. Wang J, Chi DS, Kalin GB, Sosinski C, Miller LE, Burja I, Thomas E. Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614-1709, USA. Although it is fairly well accepted that Helicobacter pylori infection plays a significant role in causing gastric cancer, the exact mechanisms involved in its pathogenesis are unclear. We have examined the relationship between H. pylori infection and oncogene expression in different stages of disease progression from precursor lesions to gastric carcinoma. We used Diff-Quik stain to diagnose H. pylori infection and immunohistochemical stains against c-erbB-2, p53, ras, c-myc, and bcl-2 to determine expression of oncogenes. H. pylori infection was found in all cases of chronic gastritis, atrophic gastritis, intestinal metaplasia, and early gastric carcinoma, and in 16 of 30 (53%) cases of advanced gastric carcinoma. Overexpression of c-erbB-2 was found in 2 (7%) cases of advanced gastric carcinoma, which were H. pylori negative. Suppressor gene, p53, was overexpressed in 3 (30%) cases of intestinal metaplasia, 2 (33%) cases of early gastric carcinoma, and 18 (60%) cases of advanced gastric carcinoma. Of these 18 p53-positive advanced gastric cancer cases, 11 (61%) were H. pylori positive. Expression of ras p21 was found in 4 (40%) cases of H. pylori-negative normal mucosa, 10 (100%) cases of chronic gastritis, 1 (10%) case of atrophic mucosa, 6 (60%) cases of intestinal metaplasia, 2 (33%) cases of nonneoplastic mucosa adjacent to early gastric carcinoma, and 7 (23%) nonneoplastic mucosa adjacent to advanced gastric carcinoma, all of which showed H. pylori. No evidence of expression of either c-myc or bcl-2 was detected in any of the above-mentioned samples. The data suggest that H. pylori infection may increase expression of ras p21 proteins and induce p53 suppressor gene mutation early in the process of gastric carcinogenesis. PMID: 11837709 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 310: Haematologica. 2002 Feb;87(2):196-214. Proliferate and survive: cell division cycle and apoptosis in human neuroblastoma. Borriello A, Roberto R, Della Ragione F, Iolascon A. Department of Biochemistry and Biophysics F. Cedrangolo, Medical School, Second University of Naples, Italy. BACKGROUND AND OBJECTIVES: Neuroblastoma is one of the most frequent childhood cancers and a major cause of death from neoplasias of infancy. Although a wealth of studies on its molecular bases have been carried out, little conclusive information about its origin and evolution is available. EVIDENCE AND INFORMATION SOURCES: Some intriguing findings have correlated neuroblastoma development with aberrations of two pivotal cellular processes generally altered in human cancers, namely cell division cycle and apoptosis. Indeed, it has been reported that neuroblastoma cell lines show accumulation of Id2 protein, a factor which is able to hamper the pRb protein antiproliferative activity. STATE OF THE ART: The increased Id2 is due to N-myc gene amplification and overexpression, a phenomenon frequently observed in neuroblastoma and an important independent negative marker. Moreover, neuroblastoma cells are frequently characterized by increased levels of survivin, an inhibitor of the apoptotic response, and by a deficiency of procaspase 8, a key intermediate of the programmed cell death cascade. These two events, probably, make neuroblastomas more resistant to programmed cell death. These recent findings might suggest that neuroblastoma cells have acquired the capability to proliferate easily and die difficultly. PERSPECTIVES: The mechanistic meaning of these data will be discussed in the present review. Moreover, we will suggest new therapeutic scenarios opened up by the described alterations of cell cycle and apoptosis engines. PMID: 11836171 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 311: Zhonghua Yan Ke Za Zhi. 1999 Jul;35(4):252-4, 14. [A study of expression of p53, c-myc and PCNA in retinoblastoma] [Article in Chinese] Yang X, Zhang Z, Zeng Q. Department of Ophthalmology, Nanjing Children Hospital, Nanjing 210008. OBJECTIVE: To investigate the expressions of p53, c-myc (oncogene) and proliferating cell nuclear antigen (PCNA) in retinoblastoma (Rb) and the relationships of the expression to the degree of differentiation and optic nerve infiltration. METHOD: The expressions of p53, c-myc and PCNA in Rb tissues of 31 cases were analyzed by using LSAB immunohistochemical method. RESULTS: The positive rates of p53, c-myc and PCNA in Rb were respectively 51.6%, 45.2% and 67.7% and all the expressions were significantly related to the differentiation degree of Rb (all P < 0.05). The expression of PCNA was significantly related to the optic nerve infiltration of Rb (P < 0.05). Both the expressions of p53 and c-myc in Rb were markedly correlated with the expression of PCNA (all P < 0.05). CONCLUSIONS: The occurrence of Rb is the result of multiple gene mutations. The determinations of p53, c-myc and PCNA are of significance for evaluating the histologic characteristics and biological behavior of Rb. PMID: 11835814 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 312: Zhonghua Wai Ke Za Zhi. 2000 May;38(5):378-81. [Mechanism of abnormal scars with treatment of steroid] [Article in Chinese] Bao W, Xu S. Research Center of Plastic Surgery, Third Clinical School, Beijing Medical University, Beijing 100083, China. OBJECTIVE: To investigate the mechanism of steroid in treatment of abnormal scars. METHODS: Apoptosis of different fibroblasts from 6 samples with keloid, 6 samples with hypertrophic scar, and 6 samples of normal skin was observed under the condition of the media containing steroid in vitro. Proliferation, biosynthesis and apoptosis of fibroblasts of 6 samples of hypertrophic scars treated with intralesional injection of steroid were studied in vivo. RESULTS: Steroid could induce apoptosis of different fibroblasts in vitro in correspondence with increasing ratio of Bax/Bcl-2 proteins. Intralesional injection of steroid could inhibit proliferation of fibroblasts from hypertrophic scars by inhibiting PDGF-BB gene expression in vivo. Intralesional injection of steroid could inhibit procollagen gene expression to prohibit type I and III protein syntheses of fibroblasts from hypertrophic scars in vivo by inhibiting gene transcription. Intralesional injection of steroid could increase c-myc and p53 gene expression of hypertrophic scars in vivo, which induced apoptosis of cells. CONCLUSION: The effects of steroid on abnormal scars were achieved by inhibiting proliferation and biosyntheses of fibroblasts and promoting apoptosis of fibroblasts. PMID: 11832064 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 313: Folia Histochem Cytobiol. 2001;39 Suppl 2:81-3. Effect of tyrphostins on programmed cell death in colon adenocarcinoma cell line LS-180. Dudzisz-Sledz M, Mizerski G, Marzec B, Korszen-Pilecka I, Rudzki S, Wojcierowski J, Mandziuk S. Department of Human Genetics, Medical University, Lublin, Poland. mdudzisz@yahoo.com Programmed cell death is an important process in the regulation of cellular proliferation, rest, differentiation and death. It is a genetically controlled process with characteristic biochemical and morphological features. Apoptosis directly regulates tumorigenesis and its induction could be a useful method of cancer therapy. Cancer cells could be influenced by some factors which induce apoptosis. We investigated the influence of tyrphostins, that specifically inhibits protein tyrosine kinases and stops the cell cycle in apoptosis of the colon adenocarcinoma cell line LS180. We used them at the concentration of 1-10 microM for 24 and 48 hours. We detected apoptosis using techniques that monitor either biochemical and morphological features of this process, such as staining with 7-amino-actinomycin D, staining with Grunwald-Giemsa, TUNEL reaction, in situ hybridization and with immunoperoxidase staining procedures. We examined the expression of genes and proteins connected with programmed cell death (p53, c-myc, p21, bcl-2). We estimated the results by cytophotometry and documented them by colour photography. We found that tyrphostin rapidly inhibits the cell cycle, particularly at the concentration of 5 microM. The expression of genes and proteins was strongly correlated with the increased apoptotic cell death conforming to the results of TUNEL and staining methods. PMID: 11820638 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 314: World J Gastroenterol. 2001 Jun;7(3):403-6. Function of apoptosis and expression of the proteins Bcl-2, p53 and C-myc in the development of gastric cancer. Xu AG, Li SG, Liu JH, Gan AH. Research Laboratory of Digestive Disease, Huizhou Central People's Hospital, No.41 Elingbei Road, Huizhou 516001, Guangdong Province, China. PMID: 11819799 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 315: Cancer Res. 2002 Jan 15;62(2):575-9. Loss of the p21(Cip1/Waf1) cyclin kinase inhibitor results in propagation of horizontally transferred DNA. Bergsmedh A, Szeles A, Spetz AL, Holmgren L. Cancer Center Karolinska Hospital, Karolinska Institutet, S-171 76 Stockholm, Sweden. We have shown previously that phagocytosis of cells dying by apoptosis results in transfer of whole or fragments of chromosomes into the nucleus of the recipient cell. Although DNA transfer was detected in normal cells, stable propagation of the transferred DNA was only observed in cells deficient in p53. Here we show that mouse embryonic fibroblast cells lacking the p21 (Cip1/Waf1) cyclin-kinase inhibitor are able to propagate DNA engulfed by phagocytosis of apoptotic bodies. Feeding mouse embryonic fibroblast p21(-/-) cells with apoptotic bodies derived from a rat fibrosarcoma resulted in focus formation in vitro and tumor formation in vivo. In contrast, cells lacking the p19 alternative reading frame gene did not show any evidence of transformation. These data indicate that p53, via the activation of p21, blocks normal cells from replicating transferred DNA from engulfed apoptotic bodies. This may be one protection level against the propagation of potentially pathological DNA. PMID: 11809712 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 316: J Biol Chem. 2002 Apr 5;277(14):11617-20. Epub 2002 Jan 22. Signaling networks that link cell proliferation and cell fate. Sears RC, Nevins JR. Department of Genetics, Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA. Publication Types: Review Review, Tutorial PMID: 11805123 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 317: Oncogene. 2002 Jan 10;21(2):165-75. Restoration of p53 expression sensitizes human papillomavirus type 16 immortalized human keratinocytes to CD95-mediated apoptosis. Aguilar-Lemarroy A, Gariglio P, Whitaker NJ, Eichhorst ST, zur Hausen H, Krammer PH, Rosl F. Forschungsschwerpunkt Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany. To understand the function of the individual oncogenes of HPV16 in modulating the cellular response to apoptogenic signals, we used human keratinocytes immortalized with either E6, E7 or E6/E7 oncoproteins as model system. Applying CD95 antibodies or recombinant CD95 ligand, only the E7-immortalized cells underwent extensive apoptosis. In contrast, E6- and E6/E7-expressing keratinocytes were resistant. Dominance of E6 correlated with significant down-regulation of p53, c-Myc, p21 and Bcl-2. CD95 was found to be reduced in resistant HPV-positive cells, while there were no quantitative differences in expression levels of FADD, FLICE/caspase-8 or caspase-3. Notably, in contrast to primary human keratinocytes, all immortalized cells showed a general reduction of c-FLIP, an inhibitory protein which normally prevents unscheduled CD95-induced apoptosis. E6- and E6/E7-positive keratinocytes, however, can be sensitized to CD95 apoptosis by blocking proteasome-mediated proteolysis. CD95-resistant HPV-positive cells underwent apoptosis within 3-5 h upon co-incubation with MG132 and agonistic antibodies or CD95 ligand, which was preceded by a strong re-expression of p53 and c-Myc, but not of other half-life controlled proteins such as Bax or IkappaBalpha. Blockage of proteasomal activity alone did not result in apoptosis, although the same set of pro-apoptotic proteins was up-regulated. Performing similar experiments with cervical carcinoma cells expressing mutated p53 (C33a) or with p53-'null' lung carcinoma cells (H1299), no CD95 cell killing occurred even though c-Myc was strongly induced. These data indicate that the reduced bioavailability of p53 is a key-regulatory event in perturbation of CD95 signaling in HPV16 immortalized keratinocytes. PMID: 11803460 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 318: Zhonghua Jie He He Hu Xi Za Zhi. 2001 Jun;24(6):371-4. [Expression of surviving gene and its relationship with expression of P53, c-myc, k-ras proteins in non-small-cell lung cancer] [Article in Chinese] Wang X, Chen S, Zhang Z. Research Laboratory of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. OBJECTIVE: To study the expression of surviving and its relationship with expression of P53, c-myc, k-ras in non-small-cell lung cancer (NSCLC). METHODS: Expression of the surviving mRNA was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR) in 76 NSCLC tumor samples, 20 benign phymatoid lesion and 21 adjacent normal lung tissue samples. Immunohistochemical assay was to detect the expression of P53, c-myc, k-ras proteins. RESULTS: Expression of surviving gene was detected in a significantly greater proportion of NSCLC (61%) than phymatoid lesion (30%) and adjacent normal lung tissue (19%) (P < 0.001). There was no relationship between surviving gene expression and histologic subtype, differentiation, TNM stages, or lymph node metastases. The expression of surviving gene correlated with P53 or c-myc expression, but not k-ras expression. CONCLUSION: (1) The up-regulation expression of surviving gene in NSCLC suggested that surviving may play a role in the pathway of carcinogenesis and surviving may be identified as a potential therapeutic target in NSCLC. (2) surviving, de-activation of antioncogene P53 and up-regulation of oncogene c-myc might play synergetic roles in the process of carcinogenesis of NSCLC. But surviving and k-ras may be independently involved in the pathogenesis of lung cancer. PMID: 11802993 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 319: Zhonghua Yi Xue Za Zhi. 2000 Jul;80(7):530-3. [Apoptosis in atrophic skeletal muscle induced by brachial plexus injury in rats] [Article in Chinese] Tian T, Wu Z, Jin H. Department of Pathophysiology, Shanghai Medical University, Shanghai 200032, China. OBJECTIVE: To study the role of apoptosis and the expression of apoptosis-associated genes in skeletal muscle atrophy induced by brachial plexus injury in rats. METHODS: Rat models of skeletal muscle atrophy were established by cutting off brachial plexus of one upper limb. Apoptosis of muscular cells was investigated by TUNEL, flowcytometry, DNA electrophoresis and electromicroscopic observation. The apoptosis associated genes such as Fas, FADD, Caspase 8, c-myc, P53 and Bcl-2 were detected by immunohistochemical method (ABC) and Northern-blot. RESULTS: It was found with TUNEL and flowcytometry that the percentage of apoptotic muscle cell rose obviously in atrophic skeletal muscle (P < 0.05). DNA laddering could be seen in DNA gel electrophoresis of atrophic muscle after brachial injury. Morphologic changes of early stage in apoptotic cell could be seen under eletcromicroscope, such as the aggregation of chromosome, the expansion of nucleic cistern and the contraction of nucleus. Fas, FADD and Caspase genes were expressed highly and Bcl-2 gene was expressed lowly with immunohistochemical method in atrophic muscle. The results were all significantly different with that of the controls (P < 0.01). But the expression changes in P53 and c-myc genes were not obvious. The result of Northern-blot indicated that the mRNA of Fas gene rose and that of Bcl-2 gene decreased obviously (P < 0.01) in atrophic muscle induced by brachial plexus injury. CONCLUSION: There are much more apoptotic cells in atrophic muscle induced by brachial plexus injury, and apoptosis plays an important role in its pathogenesis. The apoptotic signal maybe transmitted through Fas-->FADD-->Caspase 8, and the decrease in Bcl-2 gene expression aggravates the process. PMID: 11798813 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 320: Mod Pathol. 2002 Jan;15(1):35-44. Loss of p53 and c-myc overrepresentation in stage T(2-3)N(1-3)M(0) prostate cancer are potential markers for cancer progression. Qian J, Hirasawa K, Bostwick DG, Bergstralh EJ, Slezak JM, Anderl KL, Borell TJ, Lieber MM, Jenkins RB. Department of Laboratory Medicine and Pathology, Section of Biostatistics, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA. To determine whether genetic changes are markers of cancer progression and patient survival in Stage T(2-3)N(1-3)M(0) prostatic carcinoma, we compared 26 patients who died of tumor relapse after prostatectomy and lymphadenectomy (case group) with 26 matched patients who were alive at the time of the matched case's death (control group). Nine unmatched cases were also included in this study. In 37 cases, paired primary tumors (119 foci) and lymph node metastases (114 foci) were available for study. Fluorescence in situ hybridization (FISH) with centromere-specific probes for chromosomes 7, 8, and 17 and region-specific probes for D7S486 (7q31), c-myc (8q24), LPL (8p22), and p53 (17p13) was performed on available primary carcinomas and lymph node metastases. In primary tumor foci, +7q31, -8p22, +c-myc, substantial additional increases of myc (AI-c-myc), and -p53 were observed in 65%, 74%, 43%, 29%, and 31% of foci, respectively. AI-c-myc was strongly associated with higher cancer Gleason score (P =.003). Heterogeneity of genetic changes was frequently observed among multiple cancer foci. Lymph node metastases of prostate cancer usually shared genetic changes with paired primary tumors. In addition, the genetic change pattern with -8p, +c-myc or AI-c-myc, +7q, and +p53 was slightly higher in lymph node metastases (22%) than in primary tumors (6%) (P =.08). In matched case and control patients, simultaneous gain of 7q31 (+7q31) and CEP7 (+CEP7) was identified in 59% and 68% of specimens for case and control groups, respectively (P =.48). Loss of 8p22 (-8p22) was identified in 77% and 69% of specimens for case and control groups, respectively (P = 1.0). Simultaneous gain of c-myc (+c-myc) and CEP8 (+CEP8) without overt additional increase of c-myc copy number relative to CEP8 copy number, was identified in 38% and 54% of specimens for case and control groups, respectively (P =.27). AI-c-myc was identified in 54% and 23% of specimens for case and control groups, respectively (odds ratio = 3.0, P =.06). Loss of p53 (-p53) was identified in 46% and 15% of specimens for case and control groups, respectively (odds ratio = 4.0, P =.04). Our results indicate that FISH anomalies are very common in both primary tumors and lymph node metastases of Stage T(2-3)N(1-3)M(0) prostate cancer; that AI-c-myc is associated with higher cancer Gleason score; that AI-c-myc and -p53 are associated with prostate cancer progression and are potential markers of survival in Stage T(2-3)N(1-3)M(0) prostate cancer; and that lymph node metastases usually have similar or additional genetic changes compared with primary tumors, and multiple lymph node metastases usually have similar genetic changes. PMID: 11796839 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 321: Genes Chromosomes Cancer. 2002 Feb;33(2):217-24. Genome-wide search for loss of heterozygosity in Burkitt lymphoma cell lines. Sobol H, Benziane A, Kerangueven F, Yin L, Noguchi T, Pauly S, Eisinger F, Longy M, Romeo G, Lenoir G, Birnbaum D. EPI 9939 Inserm, Institut Paoli-Calmettes, IFR57, Universite de la Mediterranee, Marseille, France. The molecular biological characteristics of Burkitt lymphoma (BL), in addition to the presence of the Epstein-Barr virus (EBV) in some forms, relies on well-characterized alterations, such as MYC translocations and TP53 inactivations. To ascertain the number and location of other genome alterations, we used 191 polymorphic markers in a genome-wide search for loss of heterozygosity (LOH) in 31 Burkitt lymphoma cell lines and their normal counterparts. We were able to distinguish two types of altered allelic patterns: a bona fide LOH profile, indicative of deletion (LOH), and a profile indicative of increased dosage (ID). The former type was most frequent at chromosome arm 17p, most likely indicating TP53 gene inactivation. Increased dosage at 1q was found almost exclusively in non-EBV cell lines (P < 0.00004) and correlated well with karyotypic abnormalities affecting region 1q21-25. Our results suggest that a gene important for BL pathogenesis is located in region 1q21-25 and that the activation of this gene mimics the effects of EBV. Copyright 2002 Wiley-Liss, Inc. PMID: 11793449 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 322: Am J Chin Med. 2001;29(3-4):445-58. Effects of uwhangchungsimwon on cell viability, proliferation, and gene expression of human neuronal cell line IMR32. Song K, Kim YS, Moon SK, Ko CN, Cho KH, Bae HS, Lee KS. Department of Circulatory Internal Medicine, College of Oriental Medicine, Kyung Hee University, Seoul, Korea. Uwhangchungsimwon (pill, UC) is one of the traditional Korean medical prescriptions that has been most frequently used for stroke. To characterize the effects of UC on human neuronal cells, the human neuroblastoma cell line IMR32 was treated with UC, and cell viability, cell proliferation, apoptosis, and gene expression were analyzed. The effect of UC on recovery of cell viability was analyzed following stress induction by nutrient depletion or cold shock. Flow cytometric analysis of the cell cycle showed that UC inhibits cell cycle progression of IMR32 in a dose- and time-dependent manner. UC was also identified to increase cell viability and suppress apoptosis induction by a DNA-damaging agent, etoposide. Quantitative RT-PCR analysis revealed that expressions of the p53 tumor suppressor gene and its downstream effect, Waf1, are stimulated whereas expressions of positive cell cycle regulators, c-Myc, c-Fos, and Cyclin D1 were repressed by UC treatment. Moreover, while expression levels of apoptosis inhibitors, Bcl-2 and Bcl-XL were increased following UC treatment, that of an apoptosis promoter, Bax, was decreased. In addition, expression of BMP-7, which has been recently demonstrated to improve the motor neuron recovery from stroke, was induced by UC while it was not detected in untreated cells. Taken together, our data suggest that the pharmacoclinical effects of UC might be derived in part from its negative regulation of cell proliferation and apoptosis through the transcriptional control of related genes. PMID: 11789587 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 323: Cardiol Clin. 2001 Feb;19(1):75-89, viii. Apoptotic proteins. p53 and c-myc related pathways. McCarthy N, Mercer J, Bennett M. Division of Cardiovascular Medicine, Addenbrookes Hospital, Cambridge, United Kingdom. c-Myc and p53 are two proteins that have critical roles in the regulation of apoptosis and the cell cycle. The authors review how these two proteins are thought to control the opposing events of proliferation and apoptosis and examine whether their well-documented biological roles in tumorigenesis can be applied to the vascular system. Publication Types: Review Review, Tutorial PMID: 11787815 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 324: Oncogene. 2001 Dec 13;20(57):8193-202. The critical role of the PE21 element in oncostatin M-mediated transcriptional repression of the p53 tumor suppressor gene in breast cancer cells. Li C, Ahlborn TE, Tokita K, Boxer LM, Noda A, Liu J. Department of Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA. Cytokine oncostatin M (OM) exerts growth-inhibitory and differentiative effects on breast cancer cells. Previously we showed that the transcription from the p53 gene in breast cancer cells was down regulated by OM. To elucidate the molecular mechanisms underlying the OM effect on p53 transcription, in this study, we dissected the p53 promoter region and analysed the p53 promoter activity in breast tumor cells. We showed that treatment of MCF-7 cells with OM induced a dose- and time-dependent suppression of p53 promoter activity. The p53 promoter activity was decreased to 35% of control at 24 h and further decreased to 20% at 48 h by OM at concentrations of 5 ng/ml and higher. Deletion of the 5'-flanking region of the p53 promoter from -426 to -97 did not affect the OM effect. However, further deletion to -40 completely abolished the repressive effect of OM. The p53 promoter region -96 to -41 contains NF-kappaB and c-myc binding sites, and a newly identified UV-inducible element PE21. Mutations to disrupt NF-kappaB binding or c-myc binding to the p53 promoter decreased the basal promoter activity without affecting the OM-mediated suppression, whereas mutation at the PE21 motif totally abolished the OM effect. We further demonstrated that insertion of PE21 element upstream of the thymidine kinase minimal promoter generated an OM response analogous to that of the p53 promoter. Finally, we detected the specific binding of a nuclear protein with a molecular mass of 87 kDa to the PE21 motif. Taken together, we demonstrate that OM inhibits the transcription of the p53 gene through the PE21 element. Thus, the PE21 element is functionally involved in p53 transcription regulated by UV-induction and OM suppression. PMID: 11781835 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 325: Chin Med J (Engl). 2000 Jan;113(1):84-8. Overexpression of Bcl-2 partly inhibits apoptosis of human cervical cancer SiHa cells induced by arsenic trioxide. Deng Y, Lin C, Zheng J, Fu M, Liang X, Chen J, Xiao P, Wu M. Institute of Medicinal Plants, CAMS & PUMC, Beijing 100094, China. OBJECTIVE: To study the biological effect of arsenic trioxide (As2O3) on human cervical cancer SiHa cells and SiHa cells overexpressing bcl-2 gene. METHODS: SiHa cells with overexpression of Bcl-2 (SiHa-Bcl2 cells) were established by transfecting SiHa cells with Bcl-2 expression vector. The sensitivities of SiHa and SiHa-Bcl2 cells to As2O3 were determined using MTT (Thiazolyl blue) reduction and colony forming ability assay, morphological analysis, flow cytometric analysis, DNA agarose gel electrophoresis, in situ cell death detection (TUNEL), Northern blot, RT-PCR and Western blot. RESULTS: As2O3 inhibited the growth of SiHa cells and induced G2/M arrest and apoptosis of the cells. RT-PCR and Western blot analysis revealed that As2O3 induced SiHa cell apoptosis possibly via inhibiting the expression of HPV16 E7 and decreasing the expression of c-myc. However, we found that SiHa-Bcl2 cells partly resisted As2O3 induced apoptosis, which might be related to the prevention of the down-regulation of HPV16 E7 and c-myc gene expression. Nevertheless, As2O3 at a high concentration could still induce apoptosis of SiHa-Bcl2 cells mainly via decreasing Bcl-2 expression and slightly inhibiting viral gene expression. CONCLUSION: As2O3 is an inducer of the apoptosis of human cervical carcinoma cells and the cells overexpressing Bcl-2 can partly resist As2O3 induced apoptosis, but the exact mechanism is unclear. PMID: 11775218 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 326: Apoptosis. 2002 Feb;7(1):5-12. Mechanism of basic fibroblast growth factor-induced cell death. Burchill SA, Westwood G. Candlelighter's Children's Cancer Research Laboratory, ICRF Cancer Medicine Research Unit, St James's University Hospital, Beckett Street, Leeds LS9 7TF, United Kingdom. s.a.burchill@leeds.ac.uk Basic fibroblast growth factor (bFGF) is a potent mitogen for a number of different cell types. Its over-expression has been implicated in transformation and malignant progression. The use of bFGF to treat malignancy is therefore counterintuitive. However, recent studies have shown bFGF-induces cell death in some tumour types. This mini review will summarise the most recent findings on bFGF-induced cell death and discuss its potential mechanism of action. Publication Types: Review Review, Tutorial PMID: 11773700 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 327: Nippon Rinsho. 2001 Dec;59(12):2316-21. [Disease-related gene and tumor progression] [Article in Japanese] Mitani K. Department of Hematology, Dokkyo University School of Medicine. Chronic myelogenous leukemia is a stem cell tumor characterized by the t(9; 22)(q34; 11) translocation generating the BCR/ABL chimeric gene. The BCR/ABL fusion gene shows several functions, including inhibition of adhesion to stroma cells and extracellular matrix, activation of mitogenic signalings, inhibition of apoptosis, and degradation of inhibitory proteins, and thereby causes transformation of hematopoietic progenitors. Among its functions, the signal transduction pathways activated by the fusion gene are Ras and MAP kinase pathways, Jak-Stat pathways, PI3 kinase pathways, and Myc pathways. Molecular mechanisms in blastic crisis remains largely unknown. However, loss of functions of tumor suppressor genes such as p53, RB, and p16, activation of oncogene Ras, overexpression of Evi-1 might be involved in disease progression. Publication Types: Review Review, Tutorial PMID: 11766332 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 328: Hematol Oncol Clin North Am. 2001 Oct;15(5):931-56, ix. Pathways of apoptosis and the modulation of cell death in cancer. Fisher DE. Division of Pediatric Hematology and Oncology, Children's Hospital, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. Although cell death once was viewed exclusively as the disordered, chaotic outcome of metabolic catastrophe, apoptosis now is recognized as a highly ordered, evolutionarily conserved, and genetically selected program that is essential for normal development. The death receptor pathway of apoptosis, cytotoxic T cells, prolife survival signals, Bcl-2 family of regulators, p53 and regulated cell death in cancer, and oncogenes are reviewed. Future prospects in this arena also are discussed. Publication Types: Review Review, Tutorial PMID: 11765380 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 329: Essays Biochem. 2001;37:109-20. To live or die--a cell's choice. Link M, Harrison DJ. Department of Pathology, University of Edinburgh, Medical School, Teviot Place, Edinburgh EH8 9AG, U.K. Cell death is one of several choices a cell faces in response to injury. The cell's inherent properties and its external environment determine which pathway is chosen. Interaction between transcription factors such as p53, E2F and c-Myc acts to finely tune the pathway selection process. Once the cell death pathway is initiated cell, survival proteins can stop it at different stages upstream of the activation of effector caspases. The exact point of no return along the cell death pathway is unknown, but is likely to vary between cells. It is unlikely to be a single step, but rather a short process leading to irreversibility of the pathway. Publication Types: Review Review, Tutorial PMID: 11758452 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 330: J Biol Chem. 2002 Mar 8;277(10):8482-91. Epub 2001 Dec 18. Erratum in: J Biol Chem 2002 Nov 15;277(46):44588. The heparin-binding domain and V region of fibronectin regulate apoptosis by suppression of p53 and c-myc in human primary cells. Kapila YL, Wang S, Dazin P, Tafolla E, Mass MJ. Department of Stomatology, School of Dentistry, University of California San Francisco, San Francisco, California 94143, USA. ykapila@itsa.ucsf.edu In apoptosis the tumor suppressor p53 and the c-myc proto-oncogene are usually up-regulated. We show a novel alternative pathway of apoptosis in human primary cells that is mediated by transcriptionally dependent decreases in p53 and c-Myc and decreases in p21. This pathway is regulated by the alternatively spliced V region and high-affinity heparin-binding domain of fibronectin. Requirements for c-Myc, p53, and p21 signals in maintaining survival and for their decreases in inducing apoptosis were demonstrated by the ability of p53, c-Myc, and p21 ectopic expression to rescue this apoptotic phenotype, and the ability of p53-deficient and c-myc antisense conditions to trigger a faster rate of apoptosis. PMID: 11751853 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 331: Exp Cell Res. 2001 Dec 10;271(2):214-22. Combination of tumor necrosis factor alpha and interferon alpha induces apoptotic cell death through a c-myc-dependent pathway in p53 mutant H226br non-small-cell lung cancer cell line. Yasuoka Y, Naomoto Y, Yamatsuji T, Takaoka M, Kimura M, Uetsuka H, Matsubara N, Fujiwara T, Gunduz M, Tanaka N, Haisa M. First Department of Surgery, Okayama University, Okayama, Japan. We investigated the role of wild-type p53 and c-myc activity in apoptosis induced by a combination of natural human tumor necrosis factor alpha (TNF-alpha) and natural human interferon alpha (IFN-alpha). Studies were performed with two human non-small-cell lung cancer cell lines, H226b, which has wild-type p53, and H226br, which has a mutant p53. The combination of IFN-alpha and TNF-alpha significantly inhibited cell growth and induced apoptotic cell death of both H226b and H226br, compared with IFN-alpha or TNF-alpha alone. Treatment with one or both cytokines did not affect the expression level of p53 in both cell lines. These results suggest that the combination of IFN-alpha/TNF-alpha induces apoptotic cell death through a p53- independent pathway. The c-myc oncogene is known to be involved in apoptosis induced by TNF. Antisense c-myc oligonucleotides have been reported to modulate cell growth or apoptosis in several cell lines. Antisense oligodeoxynucleotides were added to the culture of H226br cells before the addition of IFN-alpha/TNF-alpha. Antisense c-myc inhibited IFN-alpha/TNF-alpha cytotoxicity and apoptotic cell death. In conclusion, this study provides support for the speculation that TNF-alpha/IFN-alpha induce apoptosis through a c-myc-dependent pathway rather than a p53-dependent pathway. (c)2001 Elsevier Science. PMID: 11716533 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 332: Curr Opin Mol Ther. 1999 Jun;1(3):297-306. Oligonucleotide therapeutics: clothing the emperor. Gewirtz AM. University of Pennsylvania School of Medicine, Philadelphia 19104, USA. gewirtz@mail.med.upem.edu Oligonucleotides (ON) have been used in vitro, in vivo and clinically for the treatment viral infections, malignancies and inflammatory diseases. This review will focus on the application of ON-based therapeutics for hematological disease. The primary application of ONs has been as sequence specific inhibitors of gene expression, ie, antisense oligonucleotides (AS ON) and ribozymes. Based upon the unique expression of the Bcl-Abl neogene in CML cells, numerous studies have targeted this product with AS ONs and ribozymes. These studies demonstrate that ON targeting the breakpoint region selectively inhibit the proliferation of CML cells. Subsequent studies suggest that this effect may not be due to a true antisense effect of the ON. Other targets, which are being exploited for the treatment of hematological malignancies, include ON targeting c-myb gene, p53 and Bcl-2. All three have entered clinical trials and have been shown to be tolerated by patients. In addition to inhibition of gene expression, ON can be selected for sequence specific binding to proteins (aptamer). In particular an ON that binds to thrombin with high affinity is being explored as a potential anticoagulant. These early studies have identified limitations for first generation ON which may be solvable with newer ON chemistries and/or formulations. Although the technology is still nascent it continues to show promise. Publication Types: Review Review, Tutorial PMID: 11713794 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 333: Genes Dev. 2001 Nov 15;15(22):2934-9. Dmp1 is haplo-insufficient for tumor suppression and modifies the frequencies of Arf and p53 mutations in Myc-induced lymphomas. Inoue K, Zindy F, Randle DH, Rehg JE, Sherr CJ. Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. Loss of Dmp1, an Arf transcriptional activator, leads to spontaneous tumorigenesis in mice, causing death from various forms of cancer by two years of age. Retention and expression of the wild-type Dmp1 allele in tumors arising in Dmp1(+/-) mice demonstrate that Dmp1 can be haplo-insufficient for tumor suppression. The mean latency of E(mu)-Myc-induced B-cell lymphomas is halved on a Dmp1(-/-) or Dmp1(+/-) genetic background. Although p53 mutations or Arf deletion normally occur in approximately 50% of E(mu)-Myc-induced lymphomas, Dmp1 loss obviates selection for such mutations, indicating that Dmp1 is a potent genetic modifier of the Arf-p53 pathway in vivo. PMID: 11711428 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 334: Toxicol Appl Pharmacol. 2001 Nov 15;177(1):59-67. The heterocyclic amine, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole induces apoptosis in cocultures of rat parenchymal and nonparenchymal liver cells. Ashida H, Kihara K, Nonaka Y, Fukuda I, Shiotani B, Hashimoto T. Department of Biofunctional Chemistry, Division of Life Science, Graduate School of Science and Technology, Kobe University, Rokkodai-cho 1, Nada-ku, Kobe 657-8501, Japan. ashida@kobe-u.ac.jp In this study, we investigated the mechanism of apoptosis by 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) in cocultures of parenchymal and nonparenchymal liver cells, since the liver consists of various cell types and they cooperatively respond to chemicals. It was found that cocultures were more susceptible to cell death by Trp-P-1 than culture of each cell type alone. In cocultures, Trp-P-1 induced DNA fragmentation accompanied by the activation of 18-kDa endonuclease. Trp-P-1 (30 microM) caused a rapid increase in Bid protein level in mitochondria and the leakage of cytochrome c from mitochondria into the cytosol 15 min after treatment. On the other hand, an increase in Bax protein and a decrease in Bcl-2 protein were detected in the mitochondrial fraction 2 h after treatment following the increases in p53 protein level and DNA binding activity of NF-kappa B. Caspase-8 was activated within 30 min followed by the activation of downstream caspases as measured using the corresponding peptide substrates. The activation of caspases was also confirmed by cleavage of caspase-3, poly(ADP-ribose)polymerase, and protein kinase C-delta as analyzed by Western blotting. A peptide inhibitor of caspase-8 diminished DNA ladder formation and the activation of downstream caspases, but a caspase-9 inhibitor and pyrrolidinedithiocarbamate as an inhibitor of NF-kappa B showed only partial inhibition, suggesting that caspase-8 is the apical caspase in the cascade. These results led to the conclusion that Trp-P-1 mainly drives the caspase-8-mediated pathway that involves Bid, accompanied by a delay in the p53/NF-kappa B-mediated side pathway that involves Bax, Bcl-2, and caspase-9. Copyright 2001 Academic Press. PMID: 11708901 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 335: Oncogene. 2001 Oct 25;20(48):6983-93. Bcl-2 is an apoptotic target suppressed by both c-Myc and E2F-1. Eischen CM, Packham G, Nip J, Fee BE, Hiebert SW, Zambetti GP, Cleveland JL. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. Malignant transformation occurs in cells that overexpress c-Myc or that inappropriately activate E2F-1. Transformation occurs after the selection of cells that have acquired resistance to apoptosis that is triggered by these oncogenes, and a key mediator of this cell death process is the p53 tumor suppressor. In IL-3-dependent immortal 32D.3 myeloid cells the ARF/p53 apoptotic pathway is inactivated, as these cells fail to express ARF. Nonetheless, both c-Myc and E2F-1 overexpression accelerated apoptosis when these cells were deprived of IL-3. Here we report that c-Myc or E2F-1 overexpression suppresses Bcl-2 protein and RNA levels, and that restoration of Bcl-2 protein effectively blocks the accelerated apoptosis that occurs when c-Myc- or E2F-1-overexpressing cells are deprived of IL-3. Blocking p53 activity with mutant p53 did not abrogate E2F-1-induced suppression of Bcl-2. Analysis of immortal myeloid cells engineered to overexpress c-Myc and E2F-1 DNA binding mutants revealed that DNA binding activity of these oncoproteins is required to suppress Bcl-2 expression. These results suggest that the targeting of Bcl-2 family members is an important mechanism of oncogene-induced apoptosis, and that this occurs independent of the ARF/p53 pathway. PMID: 11704823 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 336: Leuk Lymphoma. 2001 Jun;42(1-2):207-14. Molecular analysis of mucosa-associated lymphoid tissue (MALT) lymphoma of ocular adnexa. Chen PM, Chiou TJ, Yu IT, Fan FS, Chu CJ, Kao SC, Wang WS, Liu JH, Hsu WM, Yang MH, Chao TC, Tai CJ, Hsiao LT, Lin JT, Yen CC. Division of Medical Oncology, Department of Medicine, Taipei Veterans General Hospital, National Yang-Ming University, School of Medicine, Taipei, Taiwan, R.O.C. Lymphomas of mucosa-associated lymphoid tissue (MALT) are a distinct subgroup of extranodal B-cell non-Hodgkin's lymphomas. Most studies have failed to demonstrate the clonal rearrangement of BCL-1, BCL-2 or c-MYC genes for MALT lymphomas. Further, alteration of the p53 gene is rarely demonstrated in low-grade MALT lymphomas, but can be detected in high-grade disease. Lymphomas of the ocular adnexa represent approximately eight percent of all extranodal lymphomas, most of which are MALT lymphomas, but few studies had explored the alterations of BCL-1, BCL-2, c-MYC and p53 genes specifically for ocular MALT lymphomas. We investigated the changes to BCL-1, BCL-2, c-MYC and p53 genes in these lymphomas for Taiwanese patients. Clonal rearrangement for immunoglobulin heavy-chain (IgH), BCL-1, BCL-2, c-MYC and p53 genes was examined for 16 cases of ocular MALT lymphoma. Restriction-length polymorphism and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) of the DNA, corresponding to exons 5 through 9, followed by DNA sequencing, were utilized to analyze the possible mutations of the p53 gene for these tumors. Thirteen of the cases revealed rearranged IgH genes using Southern blotting or PCR. No rearrangement of BCL-1, BCL-2, c-MYC or p53 genes was discovered, with point mutation of the p53 gene in one case. As for other types of MALT lymphomas, BCL-1, BCL-2 and c-MYC genes are not implicated in the pathogenesis of the ocular sub-group. Although alteration of the p53 gene is rare for low-grade ocular MALT lymphoma, its role in disease progression merits further research. PMID: 11699208 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 337: Free Radic Res. 2001 Aug;35(2):181-94. Protective effects of antioxidants against smokeless tobacco-induced oxidative stress and modulation of Bcl-2 and p53 genes in human oral keratinocytes. Bagchi M, Kuszynski CA, Balmoori J, Joshi SS, Stohs SJ, Bagchi D. Creighton University School of Pharmacy and Allied Health Professions, Omaha, NE, USA. The oral use of chewing tobacco has greatly increased in recent years, and this usage is associated with cancers of the mouth, lip, nasal cavities, esophagus and gut. Oral cancer accounts for 3% of all cancers in U.S.A. and is the seventh most common cancer. Previous studies in our laboratory have demonstrated the protective abilities of a novel IH636 grape seed proanthocyanidin extract (GSPE) against reactive oxygen species both in vitro and in vivo models, and provided significantly better protection as compared to vitamins C, E and beta-carotene. In the recent past, we have demonstrated smokeless tobacco (STE)-induced oxidative stress, apoptotic cell death in a primary culture of normal human oral keratinocytes (NHOK), and have compared the protective abilities of vitamins C and E, singly and in combination, and GSPE in this pathobiology [Free Rad. Biol. Med., 26, 992-1000 (1999)]. In the present study, we have assessed the protective role of vitamins C and E, and GSPE against STE-induced modulation of intracellular oxidized states in NHOK cells as demonstrated by laser scanning confocal microscopy. Approximately 11%, 26%, 28% and 50% protection were observed following incubation with vitamin C, vitamin E, a combination of vitamins C plus E, and GSPE, respectively. DNA fragmentation was assessed as an index of oxidative DNA damage and similar results were observed. Furthermore, the cellular viability and functional roles of Bcl-2, p53 and c-myc genes were assessed in STE-induced oxidative stress in NHOK cells. NHOK cells were treated with STE (0-200 micrograms/ml) for 24 h and changes in the expression of Bcl-2, p53 and c-myc genes were measured by reverse transcriptase-polymerase chain reaction (RT-PCR), and the protective effect of GSPE was assessed. Approximately a 2.0-fold increase in p53 gene expression was observed following incubation of the oral keratinocytes with 100 micrograms/ml of STE, beyond which the expression of p53 decreased, confirming increased apoptotic cell death with a higher concentration of STE as reported earlier. GSPE significantly modulated STE-induced changes in p53. The expression of antiapoptotic Bcl-2 gene decreased with STE treatment and the expression of Bcl-2 gene increased significantly following preincubation with GSPE. No significant change in the expression of transcription factor c-myc gene responsible for cell cycle growth was observed following incubation with STE and/or GSPE. Thus, c-myc may not be involved in STE-induced cytotoxicity towards NHOK cells. These results suggest that antioxidant protection of STE-induced cellular injury is associated with alterations in Bcl-2 and p53 expression. PMID: 11697199 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 338: FEBS Lett. 2001 Nov 2;507(3):259-63. Transcriptional repression of the human p53 gene by cobalt chloride mimicking hypoxia. Lee SG, Lee H, Rho HM. School of Biological Sciences, Seoul National University, 151-742, Seoul, South Korea. The switch to an angiogenic phenotype is known to be a fundamental determinant of neoplastic growth and tumor progression. We herein report that the transcription of the human p53 gene was repressed by treatment with a hypoxia-mimicking concentration of cobalt chloride and alone by hypoxia-inducible factor 1alpha. Analyses of serial deletions, site-directed mutageneses and heterologous promoter systems showed that the site responsible for the repression by both factors was the E-box element in the promoter of the p53 gene. These results alongside previous data suggest that the loss of p53 including the transcriptional repression may play an important role in the angiogenic switch during tumorigenesis. PMID: 11696352 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 339: Eur J Cancer. 2001 Nov;37(17):2247-56. A role for c-myc in DNA damage-induced apoptosis in a human TP53-mutant small-cell lung cancer cell line. Supino R, Perego P, Gatti L, Caserini C, Leonetti C, Colantuono M, Zuco V, Carenini N, Zupi G, Zunino F. Istituto Nazionale Tumori, Via Venezian 1, 20133 Milan, Italy. Based on the role of p53 in the control of apoptosis following DNA damage, the status of the TP53 gene has been implicated as a major determinant of tumour responsiveness to cytotoxic therapies. In spite of the high frequency of TP53 mutations, small-cell lung cancer (SCLC) is recognised as one of the most chemoresponsive solid tumours. Since the relevance of the TP53 gene status in the modulation of tumour responsiveness is dependent on the molecular/biological context, in the present study, we have examined the relationship between chemosensitivity and susceptibility to apoptosis of a TP53-mutant human SCLC cell line. The cell line, in spite of TP53 mutation, retained an efficient response to genotoxic stress as documented by cells ability to modulate the p53 protein, arrest in the G1 and G2 phases of the cell cycle and its marked susceptibility to apoptosis following treatment with DNA damaging agents. Exposure to DNA-damaging agents caused an increase of c-Myc, a DNA damage-responsive transcription factor. An analysis of damage-induced apoptosis in the presence of an anti-Fas/CD95 inhibitory antibody indicated that Fas/CD95 was not required for the apoptotic response. The results support an implication of c-myc in sensitising cells to apoptosis, since inhibition of c-Myc expression with an antisense oligodeoxynucleotide (AS-ODN) almost abolished the drug-induced apoptotic response. In conclusion, the present results support a role for c-myc in the induction of apoptosis by genotoxic stress in the absence of a functional p53 and provide new insights into the mechanisms that may influence apoptosis in TP53-mutant cells. Elucidation of this pathway and of the possible cooperation with p53-dependent mechanisms may provide a basis for therapeutic intervention. PMID: 11677115 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 340: Gynecol Oncol. 2001 Nov;83(2):216-20. Predictors of outcome in small cell carcinoma of the cervix--a case series. Straughn JM Jr, Richter HE, Conner MG, Meleth S, Barnes MN. Division of Gynecologic Oncology, University of Alabama at Birmingham, 618 South 20th Street, Birmingham, Alabama 35233, USA. jmstraughtn@yahoo.com OBJECTIVE: The objective of this study was to determine whether clinicopathologic findings or the immunohistochemical presence of molecular markers are predictive of clinical outcome in patients with small cell carcinoma of the cervix (SCCC). METHODS: A retrospective review of cases of carcinoma of the cervix was conducted to identify SCCC. From 1978 to 1999, 16 patients were identified at our institution with the diagnosis of SCCC. Microscopic sections of paraffin-embedded tissue specimens were evaluated for confirmation of diagnosis. Specimens were immunohistochemically stained with antibodies to three neuroendocrine markers: neuron-specific enolase, chromagranin (CGR), and synaptophysin. Specimens were also stained for protein expression of p53, erbB2, proliferating cell nuclear antigen, and c-myc. The relationship between molecular markers and clinical outcome was determined. RESULTS: All 16 cases met the histologic criteria for SCCC. Fourteen of 16 tumors (88%) stained positive for neuroendocrine differentiation. Eleven of 16 patients (69%) died from disease with a median survival of 19 months; there were 3 long-term survivors (greater than 5 years). CGR was positive in 8 (50%) specimens and was found to be highly predictive of death (P = 0.001). Complete loss of p53 protein was seen in 8 patients, 7 of whom died with a median survival of 20 months. CONCLUSION: Immunohistochemistry can be helpful in confirming difficult cases of SCCC. Further studies are necessary to define molecular markers that may be predictive of outcome in patients with SCCC. Copyright 2001 Academic Press. Publication Types: Review Review, Multicase PMID: 11606074 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 341: Int J Mol Med. 2001 Nov;8(5):537-42. The genetic events of HPV-immortalized esophageal epithelium cells. Shen ZY, Xu LY, Chen XH, Cai WJ, Shen J, Chen JY, Huang TH, Zeng Y. Department of Pathology, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong 515031, P.R. China. jshen@mailserv.stu.edu.cn We studied cytogenesis, telomere and telomerase, and c-myc, ras, bcl-2, and p53 genes of cells in the progressive process of immortal epithelial cells from embryonic esophagus induced by human papillomavirus (HPV). The SHEE cell line, established by us, consist of immortalized epithelial cells from the embryonic esophagus induced by genes E6E7 of HPV type 18. It was in initial malignant transformation when cultivated over 60 passages without co-carcinogens. Cells of the 10th, 31st, and 60th passages were represented in the progressive process within the immortal period. In these three stages of the cell line, the modal number of chromosome and karyotypes were analyzed. The telomere length was assayed by Southern blot methods, and the telomerase activity was analyzed by hTR and hTERT assay. C-myc, p53, bcl-2, ras genes were assayed by the multi-PCR method. The morphology of the 10th passage cells exhibited good differentiation, the 60th passage cells were relatively poorly differentiated, and the 31st passage cells differentiated in two distinct ways. The growth characteristics of the 31st and 60th passage cells were weakened at contact-inhibition and anchorage-dependent growth. Karyotypes of three cell passages belonged to hyperdiploid and hypotriploid with abnormal chromosomes +1, +3, +7, +9, +17, +18; del(1)(p32); der(4), t(4;?)(q31;?); der(5),t(5;?)(q31;?); der(13),t(13;13)(p11;q11) and others. Bimodal distribution of chromosomes with more aberrant chromosomes appeared in the 31st and 60th passage cells. Telomere length sharply shortened from normal fetal esophagus to the 10th and 31st passage step by step, but was stable from the 31st to the 60th passage and the telomerase activities measured were expressed at late two passages. p53 mutant was positive in three passages, c-myc was positive in the 31st and the 60th passage K-ras only in the last. The results reveal that changes of chromosomes, telomere length, telomerase activity and certain gene expressions are important events of HPV-immortalized esophageal epithelium cells. All of these changes occurred in dynamic progressive process. This cell line may be useful for the elucidation of the genetic mechanism of cellular immortalization. PMID: 11605024 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 342: Mol Cell Biol. 2001 Nov;21(22):7653-62. Bax loss impairs Myc-induced apoptosis and circumvents the selection of p53 mutations during Myc-mediated lymphomagenesis. Eischen CM, Roussel MF, Korsmeyer SJ, Cleveland JL. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. ceischen@unmc.edu The ARF and p53 tumor suppressors mediate Myc-induced apoptosis and suppress lymphoma development in E mu-myc transgenic mice. Here we report that the proapoptotic Bcl-2 family member Bax also mediates apoptosis triggered by Myc and inhibits Myc-induced lymphomagenesis. Bax-deficient primary pre-B cells are resistant to the apoptotic effects of Myc, and Bax loss accelerates lymphoma development in E mu-myc transgenics in a dose-dependent fashion. Eighty percent of lymphomas arising in wild-type E mu-myc transgenics have alterations in the ARF-Mdm2-p53 tumor suppressor pathway characterized by deletions in ARF, mutations or deletions of p53, and overexpression of Mdm2. The absence of Bax did not alter the frequency of biallelic deletion of ARF in lymphomas arising in E mu-myc transgenic mice or the rate of tumorigenesis in ARF-null mice. Furthermore, Mdm2 was overexpressed at the same frequency in lymphomas irrespective of Bax status, suggesting that Bax resides in a pathway separate from ARF and Mdm2. Strikingly, lymphomas from Bax-null E mu-myc transgenics lacked p53 alterations, whereas 27% of the tumors in Bax(+/-) E mu-myc transgenic mice contained p53 mutations or deletions. Thus, the loss of Bax eliminates the selection of p53 mutations and deletions, but not ARF deletions or Mdm2 overexpression, during Myc-induced tumorigenesis, formally demonstrating that Myc-induced apoptotic signals through ARF/Mdm2 and p53 must bifurcate: p53 signals through Bax, whereas this is not necessarily the case for ARF and Mdm2. PMID: 11604501 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 343: Cancer Lett. 2001 Nov 28;173(2):163-74. Inhibition of apoptosis by pentachlorophenol in v-myc-transfected rat liver epithelial cells: relation to down-regulation of gap junctional intercellular communication. Sai K, Kang KS, Hirose A, Hasegawa R, Trosko JE, Inoue T. Division of Cellular and Molecular Toxicology, National Institute of Health Sciences, 158-8501, Tokyo, Japan. sai@nihs.go.jp Pentachlorophenol (PCP), a promoter of murine hepatocarcinogenesis, inhibits gap junctional intercellular communication (GJIC) in rat liver epithelial cells in vitro. To test the hypothesis that both inhibition of GJIC and apoptosis contribute to tumor promotion, we investigated the effect of PCP on both GJIC and serum deprivation-induced apoptosis in v-myc-transfected rat liver epithelial cells. The results showed that PCP inhibited apoptosis, as measured by the TUNEL assay and DNA ladder formation. Inhibition of apoptosis was associated with a decrease in GJIC. The study demonstrated that PCP has a potential for inhibiting apoptosis and GJIC, supporting the hypothesis. PMID: 11597791 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 344: N Engl J Med. 2001 Oct 4;345(14):1065-6. Clinical response to fluorouracil and p53. Augenlicht LH, Wadler S, Arango D. Publication Types: Letter PMID: 11586966 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 345: Cancer Genet Cytogenet. 2001 Sep;129(2):107-11. An hsr on chromosome 7 was shown to be an insertion of four copies of the 11q23 MLL gene region in an HIV-related lymphoma. Reddy KS, Parsons L, Mak L, Chan JA. Cytogenetic Department, Quest Diagnostics Inc., 33608 Ortega Highway, San Juan Capistrano, CA, USA. reddyk@questdiagnostics.com A 45-year-old male with AIDS presented with a cecal diffuse large B-cell lymphoma. Cytogenetic and flourescence in situ hybridization (FISH) studies revealed a complex karyotype with multiple aberrations that included a translocation, t(8;14) involving MYC on chromosome 14. This is specific to B-cell lymphomas. There were also frequently observed secondary changes such as chromosome 1 rearrangement leading to trisomy of 1q and loss of tp53 from the deleted chromosome 17. A unique secondary abnormality was an hsr on chromosome 7, which by FISH and SKY investigations was shown to originate from chromosome 11 involving 4 copies of the MLL gene region. Publication Types: Case Reports PMID: 11566339 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 346: J Virol. 2001 Oct;75(20):9790-8. Selection for loss of p53 function in T-cell lymphomagenesis is alleviated by Moloney murine leukemia virus infection in myc transgenic mice. Baxter EW, Blyth K, Cameron ER, Neil JC. Molecular Oncology Laboratory, Department of Veterinary Pathology, University of Glasgow Veterinary School, Glasgow G61 1QH, United Kingdom. Thymic lymphomas induced by Moloney murine leukemia virus (MMLV) have provided many examples of oncogene activation, but the role of tumor suppressor pathways in these tumors is less clear. These tumors display little evidence of loss of heterozygosity, and MMLV is only weakly synergistic with the Trp53 null genotype, suggesting that viral lymphomagenesis involves mechanisms which do not require mutational loss of Trp53 function. To explore this relationship in greater depth, we infected CD2-myc transgenic mice with MMLV and examined the role of Trp53 in the genesis of these tumors. Most (19 of 27) of the tumors from MMLV-infected, CD2-myc Trp53(+/-) mice retained the wild-type Trp53 allele in vivo while tumors of uninfected CD2-myc Trp53(+/-) mice invariably showed allele loss from a significant fraction of primary tumor cells. The functional integrity of the Trp53 gene in these tumors was indicated by ongoing allele loss or selection for mutational stabilization during in vitro propagation and by the radiosensitivity of selected Trp53(+/-) tumor cell lines. An inverse correlation was noted between retention of the wild-type Trp53 allele and expression of p19(ARF), providing further evidence of negative-feedback control of the latter by p53. However, expression of p19(ARF) does not appear to be counterselected in the absence of p53, and its integrity in Trp53(+/-) tumors was indicated by its transcriptional upregulation on Trp53 wild-type allele loss in vitro in selected tumor cell lines. The role of MMLV was investigated further by analysis of proviral insertion sites in tumors of CD2-myc transgenic mice sorted for Trp53 genotype. A proportion of tumors showed insertions at Runx2, an oncogene which has been shown to collaborate independently with CD2-myc and with the Trp53 null genotype, and at a novel common integration site (ptl-1) on chromosome 8. Genotypic analysis of the panel of tumors suggested that neither of these integrations is functionally redundant with loss of p53, but it appears that the combination of the MMLV oncogenic program with the CD2-myc oncogene relegates p53 loss to a late step in tumor progression or in vitro culture. While the means by which these tumors preempt the p53 tumor suppressor response remains to be established, this study provides further evidence that irreversible inactivation of this pathway is not a prerequisite for tumor development in vivo. PMID: 11559812 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 347: Lab Invest. 2001 Sep;81(9):1299-307. Expression of presumed specific early and late factors associated with liver regeneration in different rat surgical models. Laurent S, Otsuka M, De Saeger C, Maiter D, Lambotte L, Horsmans Y. Gastroenterology Laboratories, Universite Catholique de Louvain, Brussels, Belgium. Experiments performed on the portal branch ligation (PBL) model indicate that early changes observed after surgery are not related to the regenerative process because they also occur in atrophying lobes. To further confirm the lack of specificity of the early events and to exclude the influence of circulatory factors released by proliferating lobes on their occurrence, we investigated this response after sham operation (SO) and portacaval shunt (PCS), a model characterized by liver atrophy. We also attempted to determine expression of later events associated specifically with regeneration, ie, expression of p53 or c-Ha-ras, or inhibition of proliferation, ie, interleukin-1beta (IL-1beta) and transforming growth factor-beta1 (TGF-beta1) after partial (PH) and temporary partial (TPH) hepatectomy, SO and PCS. Nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription 3 (STAT3) DNA binding were assessed by electrophoretic mobility shift assay (EMSA), interleukin-6 (IL-6) mRNA by reverse transcription-polymerase chain reaction (RT-PCR), c-myc and c-jun mRNAs by Northern blot analysis at 0.5 and 2 hours, p53 and c-Ha-ras mRNAs by Northern blot analysis at 8 and 24 hours, and IL-1beta and TGF-beta1 by RT-PCR at 24 hours. The early response including an increase of NF-kappaB, STAT3, IL-6, and immediate-early genes expression was present after PH, PCS, and SO. In SO, slight differences were observed in comparison with PH: no NF-kappaB p65/p50 DNA binding was observed, only three of six SO rats were positive for IL-6, and immediate-early genes induction showed differences in the intensity of the response. At later times, p53 mRNA increased at 8 hours after PH and TPH, c-Ha-ras mRNA at 24 hours after PH, and IL-1beta mRNA at 24 hours after PCS. Early events are not specifically associated with the reduction of liver mass or with the regenerative process, are not predictive of future cell fate, and are most likely related to surgical stress. p53 and c-Ha-ras induction is closely associated with cell cycle progression whereas IL-1beta, but not TGF-beta1, appears to be one of the negative growth regulators that might play an important role in atrophy. PMID: 11555677 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 348: Biol Sci Space. 1994 Jun;8(2):94-102. [Induction of gene expression of cancer-related genes by environmental stresses] [Article in Japanese] Matsumoto H, Ohnishi T. Department of Anatomy, Nara Medical University. Many environmental elements induce the stress response in organisms. In order to examine whether the space condition brings cancer causing on mammals, we propose the importance of the study about the effects of various environmental stresses on the gene expression of oncogenes and tumor-suppressor genes. Then we reviewed numerous findings about the induction of gene expression by environmental stresses. Many investigators have reported that three oncogenes of c-fos, c-jun and c-myc, so called "Early Response Genes", were induced at transcriptional level by a diverse set of stresses such as heat, UV and ionizing radiation, and that the accumulation of the product of a tumor-suppressor gene, p53 was induced at post-translational level by the same stresses. Publication Types: Review Review, Tutorial PMID: 11542736 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 349: Radiat Oncol Investig. 1996;3:412-9. Radiogenic transformation of human mammary epithelial cells in vitro. Yang TC, Georgy KA, Tavakoli A, Craise LM, Durante M. Radiation Biophysics Laboratory, NASA Johnson Space Center, Houston, Texas, USA. Cancer induction by space radiations is a major concern for manned space exploration. Accurate assessment of radiation risk at low doses requires basic understanding of mechanism(s) of radiation carcinogenesis. For determining the oncogenic effects of ionizing radiation in human epithelial cells, we transformed a mammary epithelial cell line (185B5), which was immortalized by benzo(a)pyrene, with energetic heavy ions and obtained several transformed clones. These transformed cells showed growth properties on Matrigel similar to human mammary tumor cells. To better understand the mechanisms of radiogenic transformation of human cells, we systematically examined the alterations in chromosomes and cancer genes. Among 16 autosomes examined for translocations, by using fluorescence in situ hybridization (FISH) technique, chromosomes 3, 12, 13, 15, 16, and 18 appeared to be normal in transformed cells. Chromosomes 1, 4, 6, 8, and 17 in transformed cells, however, showed patterns different from those in nontransformed cells. Southern blot analyses indicated no detectable alterations in myc, ras, Rb, or p53 genes. Further studies of chromosome 17 by using in situ hybridization with unique sequence p53 gene probe and a centromere probe showed no loss of p53 gene in transformed cells. Experimental results from cell fusion studies indicated that the transforming gene(s) is recessive. The role of genomic instability and tumor suppressor gene(s) in radiogenic transformation of human breast cells remains to be identified. PMID: 11541509 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 350: Oncogene. 2001 Aug 30;20(38):5341-9. Myc lacks E2F1's ability to suppress skin carcinogenesis. Rounbehler RJ, Schneider-Broussard R, Conti CJ, Johnson DG. University of Texas M.D. Anderson Cancer Center, Science Park Research Division, Park Road 1C, Smithville, Texas 78957, USA. Myc and E2F1 can each stimulate proliferation, induce apoptosis, and contribute to oncogenic transformation. However, only E2F1 has been shown to have a tumor suppressive activity under some conditions. To examine the potential of Myc to suppress tumorigenesis under one of the conditions in which E2F1 functions to suppress tumorigenesis, transgenic mice expressing Myc under the control of a keratin 5 (K5) promoter were generated. Like K5 E2F1 transgenic mice, K5 Myc transgenic mice have hyperplastic and hyperproliferative epidermis and develop spontaneous tumors in the skin and oral epithelium. In addition, K5 Myc and K5 E2F1 transgenic mice both display aberrant, p53-dependent apoptosis in the epidermis. It has been demonstrated that deregulated expression of E2F1 in the epidermis of transgenic mice inhibits tumorigenesis in a two-stage skin carcinogenesis assay. In sharp contrast to those results, deregulated expression of Myc in the epidermis of transgenic mice resulted in an enhanced response to two-stage skin carcinogenesis. We conclude that while Myc and E2F1 have similar proliferative, apoptotic and oncogenic properties in mouse epidermis, Myc lacks E2F1's tumor suppressive property. This suggests that E2F1's unique ability to inhibit skin carcinogenesis is not simply a consequence of promoting p53-dependent apoptosis. PMID: 11536046 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 351: Cell Death Differ. 2001 Jun;8(6):621-30. High constitutive level of NF-kappaB is crucial for viability of adenocarcinoma cells. Smirnov AS, Ruzov AS, Budanov AV, Prokhortchouk AV, Ivanov AV, Prokhortchouk EB. Group of Transcriptional Control and Oncogenesis, Institute of Gene Biology, Russian Academy of Sciences, Vavilova 34/5, 117334 Moscow, Russia. Most of cells exhibit low nuclear level of NF-kappaB. However, in some cell lines and tissues aberrantly activated NF-kappaB is playing an important role in cell motility, growth control and survival. Here we describe the result of decrease of constitutive NF-kappaB level in different adenocarcinoma cell lines. Treatment of mouse adenocarcinoma cell line CSML-100 with both synthetic (TPCK or PDTC) or natural (I(kappaB)-alpha) NF-kappaB inhibitors caused apoptotic death. Low doses of TPCK were harmless for CSML100 cells but sensitized them to TNF-induced apoptosis. Death of CSML100 cells in the presence of high concentration TPCK was not accompanied with significant changes in c-myc activity but strongly correlated with rapid decrease in p53 level. Thus, mutual behavior p53 and NF-kappaB represented a unique feature of TPCK-induced apoptosis in CSML-100 adenocarcinoma cells. PMID: 11536013 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 352: Cancer Res. 2001 Sep 1;61(17):6487-93. Inverse regulation of cyclin B1 by c-Myc and p53 and induction of tetraploidy by cyclin B1 overexpression. Yin XY, Grove L, Datta NS, Katula K, Long MW, Prochownik EV. Section of Hematology/Oncology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. We have shown previously that mitotic spindle inhibitors allow the c-Myconcoprotein to uncouple mitosis from DNA synthesis, resulting in the acquisition of tetraploidy. This can also occur in the absence of spindle inhibition if c-Myc deregulation is combined with inactivation of the p53 tumor suppressor. Under these conditions, cyclin B1 protein is induced but retains its normal cell cycle regulation. We now show that the cyclin B1 promoter is directly but oppositely regulated by c-Myc and p53. Enforced expression of cyclin B1 also induces tetraploidy, either after mitotic spindle inhibition or in the absence of such inhibition if cyclin B1 is coexpressed with c-Myc. Cyclin B1 represents a new class of c-Myc target genes that is also regulated by p53. It is also the first identified downstream effector of c-Myc able to produce the chromosomal instability that characterizes virtually all tumor cells. PMID: 11522645 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 353: J Neurooncol. 2001 May;52(3):195-204. Genetic basis of pituitary adenoma invasiveness: a review. Suhardja A, Kovacs K, Rutka J. Division of Neurosurgery, University of Toronto, Ontario, Canada. Compatible with contemporary paradigms of the role of genetic aberrations in the progression of human tumors, the growth of pituitary tumors into a state of invasiveness appears to be due to genetic alterations. Amplification of H-ras and c-myc oncogenes and mutations of p53, nm23 and Rb genes have been identified disproportionately more in aggressive tumors and, in the case of Rb gene, in pituitary carcinomas, providing evidence that amplification of these oncogenes (H-ras and c-myc) and inactivation of tumor suppressor genes (p53, nm23 and Rb) seem to be at least one mechanism by which pituitary tumors progress. The current level of management of invasive pituitary adenomas should become more comprehensive as the advances in our understanding of genetic basis of pituitary adenoma invasiveness becomes translated into development of novel chemotherapy or gene transfer technique. Publication Types: Review PMID: 11519849 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 354: Int J Cancer. 2001 Sep;93(6):823-31. Differential sensitivity of human papillomavirus type 16(+) and type 18(+) cervical carcinoma cells to CD95-mediated apoptosis. Aguilar-Lemarroy A, Kirchhoff S, Whitaker N, Gariglio P, zur Hausen H, Krammer PH, Rosl F. Forschungsschwerpunkt Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Heidelberg, Germany. When cervical carcinoma cells were monitored for apoptotic signals, HPV18(+) lines were found to be highly sensitive to agonistic CD95 antibodies or recombinant CD95 ligands after co-exposure with CHX (CD95(S)). In contrast, HPV16(+) cervical carcinoma cells and HPV16-immortalized non-malignant human keratinocytes were CD95-resistant (CD95(R)) under equivalent conditions. Somatic cell hybridization between CD95(S) and CD95(R) cervical carcinoma cell lines revealed that CD95 sensitivity was a dominant trait, which could be correlated with abundant c-Myc and low Bcl-X(L) expression. Although CD95(R) cervical carcinoma cells expressed even higher levels of p53 and CD95 receptor at the surface, resistance could be attributed to the inability to form a functional DISC, necessary for successful transmission of the apoptogenic response. These data indicate that resistance to apoptotic stimuli represents an important immunological escape mechanism during virus-induced carcinogenesis. Copyright 2001 Wiley-Liss, Inc. PMID: 11519044 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 355: Tunis Med. 2001 May;79(5):326-8. [Apoptosis] [Article in French] Hamzaoui K. Publication Types: Congresses PMID: 11515476 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 356: Leuk Res. 2001 Sep;25(9):793-800. Effects of Matrine on proliferation and differentiation in K-562 cells. Zhang LP, Jiang JK, Tam JW, Zhang Y, Liu XS, Xu XR, Liu BZ, He YJ. Chongqing University of Medical Science, 400046, Chongqing, People's Republic of China. We investigated the effects of Matrine on proliferation by trypan blue exclusion and differentiation by benzidine staining positive cells in K-562 cells, assayed the telomerase activity using PCR-ELISA assay, analyzed cell cycle by fluorescence-activated cell sorter analysis of the DNA content, and also determined the gene expression level of c-myc, N-ras and p53 by northern blot and dot blot analysis. The results showed that with the addition of 0.1 mg/ml Matrine, cell growth was inhibited significantly by 4 days, benizidine-positive cells rose from 1% to 2% in control cells to 15% in treated cells on day 5; treatment of K-562 cells with 0.1 mg/ml Matrine for 5 days resulted in a marked inhibition in telomerase activity, in a manner that correlated with the extent of differentiation; after exposure to Matrine for 72 h, 64.6% cells were arrested in the G1-phase of the cell cycle, the fraction of cells in S-phase had decreased from 56.9% in control cells to 24.4% in differentiated cells, and the levels of N-ras and p53 mRNA were remarkably increased for 24 and 48 h, respectively, c-myc mRNA expression level declined for 24 h and was inhibited significantly for 48 h. Our study confirmed that Matrine plays a significant effect on the inhibition of proliferation cells and inducing differentiation in K-562 cells. PMID: 11489473 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 357: Cancer Lett. 2001 Sep 28;171(1):87-101. B-myb rescues ras-induced premature senescence, which requires its transactivation domain. Masselink H, Vastenhouw N, Bernards R. Division of Molecular Carcinogenesis and Center for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands. B-myb, a ubiquitously expressed member of the myb gene family, is highly regulated throughout the cell cycle and appears to be required for cell cycle progression. In contrast to its relatives A-myb, c-myb, and v-myb, no transforming activity of B-myb has been reported thus far. We report here that B-myb can rescue senescence induced by an activated ras oncogene in rodent cells in vitro. We show that transformation by B-Myb involves its ability to activate transcription. Similar to other oncogenic transcription factors, such as c-Myc and E2F, we show that B-Myb also has repression activity. We demonstrate that the C-terminus of B-Myb can function as a repressor of transcription, that B-Myb interacts with the repressor molecules BS69 and N-CoR and that the repression function, like the transactivation domain, contributes to B-myb transformation. PMID: 11485831 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 358: EMBO J. 2001 Aug 1;20(15):4163-72. Integrity of the N-terminal transcription domain of p53 is required for mutant p53 interference with drug-induced apoptosis. Matas D, Sigal A, Stambolsky P, Milyavsky M, Weisz L, Schwartz D, Goldfinger N, Rotter V. Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel. The present study examined whether the ability of mutant p53 to block apoptosis depended on its transcriptional activity. A core domain mutant p53 (143 Val to Ala), in which two N-terminal residues (22 and 23) essential for transactivation were also mutated (Leu to Glu and Trp to Ser, respectively), was examined. While p53 containing only the core mutation efficiently interfered with drug-induced apoptosis, further modification at the N-terminus abolished this blocking activity. Furthermore, expression of c-myc, a suggested target for core mutant p53 transactivation, was elevated in the core mutant p53-expressing cells, but was abolished in the presence of the transcription-deficient p53 core mutant. In addition, wild-type p53, mutated in the N-terminus (residues 22 and 23), was unable to induce apoptosis by itself. Nevertheless, it synergized with drugs in the induction of apoptosis. This suggests that the integrity of the N-terminus is essential for both the activity of wild-type p53 in apoptosis and for mutant p53-mediated block of drug-induced apoptosis. This supports the notion that core p53 mutants act via a gain of function mechanism. PMID: 11483519 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 359: Curr Pharm Biotechnol. 2001 Jun;2(2):187-200. The cellular and molecular basis of health benefits of grape seed proanthocyanidin extract. Joshi SS, Kuszynski CA, Bagchi D. Department of Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha 68198-6395, USA. ssjoshi@unmc.edu Red grape seed extract containing proanthocyanidins and other antioxidants are being used as nutritional supplements by many health conscious individuals. The beneficial effects of grape seed proanthocyanidins (GSPE) have been reported, however, little is known about their mechanism(s) of action. One of the beneficial effects of GSPE is chemoprevention of cellular damage. The precise mechanism by which GSPE mediates, chemoprevention is not yet understood. This report addresses this issue. We investigated the mechanisms of actions of GSPE, which ameliorates chemotherapy-induced toxic effects of Idarubicin (Ida) and 4,-hydroxyperoxycyclophosphamide (4-HC) in normal human Chang liver cells. Exposure to GSPE resulted in a significant reduction in apoptosis in response to the cytotoxicity of chemotherapeutic agents. RT-PCR analysis showed a significant increase in the anti-apoptotic gene Bcl-2 and a decrease in the cell cycle associated and proapoptotic genes, c-myc and p53 in cells treated with GSPE. These results suggest that some of the chemopreventive effects of GSPE are mediated by upregulating Bcl-2 and down regulating c-myc and p53 genes. PMID: 11480422 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 360: Cancer Biother Radiopharm. 2001 Jun;16(3):213-25. Apoptosis-related gene and protein expression in human lymphoma xenografts (Raji) after low dose rate radiation using 67Cu-2IT-BAT-Lym-1 radioimmunotherapy. Kroger LA, DeNardo GL, Gumerlock PH, Xiong CY, Winthrop MD, Shi XB, Mack PC, Leshchinsky T, DeNardo SJ. Division of Hematology/Oncology, University of California Davis Medical Center, Sacramento, CA, USA. Despite low radiation dose rates, radioimmunotherapy (RIT) has proven particularly effective in the treatment of malignancies, such as lymphoma. Apoptosis has been suggested to be a major mechanism for cell death from continuous low-dose rate radiation from radioimmunotherapy. The goal of this study was to examine Raji lymphoma xenografts for induction of apoptosis and modulation of apoptosis-related gene and protein expression in response to 67Cu-2IT-BAT-Lym-1 RIT. In preclinical and clinical trials, 67Cu-2IT-BAT-Lym-1 has shown an exceptionally long tumor residence time associated with substantial cumulated radiation doses. The Raji model mirrors human lymphomas that have mutant p53 and increased BCL2 expression. Untreated athymic BALB/c nu/nu mice and mice treated with 400 micrograms Lym-1, or 335-500 microCi 67Cu on less than 400 micrograms Lym-1 antibody, were observed for toxicity and response over 84 days. Subgroups of 4-5 mice were sacrificed at 3, 6 and 24 h after therapy so that tumors could be examined for poly(ADP-ribose) polymerase (PARP) and DNA ladder evidence for apoptosis and for BCL2, p53, p21, GADD45, TGF-beta 1 and c-MYC gene and protein expression. Untreated tumors had little evidence of apoptosis and Lym-1 had no effect on apoptosis or gene expression. 67Cu-2IT-BAT-Lym-1 RIT induced an overall response rate of 50% with tolerable toxicity, and 29% of the tumors were cured at cumulated tumor radiation doses of about 1800 cGy. Apoptosis was greatly increased in the RIT treated Raji xenografts as evidenced by cleavage of PARP to the characteristic 85 kD fragment at 3 and 6 h and by the DNA cleavage pattern. BCL2 gene and protein expression were substantially decreased at 3 and 24 h, respectively, after 67Cu-2IT-BAT-Lym-1 RIT despite only modest cumulated radiation doses (56 cGy at 3 h). Evidence for apoptosis preceded tumor regression by 4-6 days. In these therapy-resistant, human lymphoma tumors treated with 67Cu-2IT-BAT-Lym-1, apoptosis was convincingly demonstrated to be a major mechanism for the effectiveness of RIT and occurred by p53-independent mechanisms. PMID: 11471486 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 361: Clin Exp Metastasis. 2000;18(5):429-38. Dietary 4-HPR suppresses the development of bone metastasis in vivo in a mouse model of prostate cancer progression. Shaker MR, Yang G, Timme TL, Park SH, Kadmon D, Ren C, Ji X, Lee HM, Sehgal I, Anzano M, Sporn MB, Thompson TC. Scott Department of Urology, Baylor College of Medicine, Houston, Texas 77030, USA. The effects of the synthetic retinoid N-(4-hydroxyphenyl) retinamide (4-HPR) on prostate cancer metastasis in vivo were evaluated in the mouse prostate reconstitution (MPR) model. MPRs were produced by infection of either heterozygous (+/-) or nullizygous (-/-) p53-mutant fetal prostatic epithelial cells with the recombinant retrovirus Zipras/myc 9. Previous studies have documented that loss of p53 function potentiates metastasis in this model system. MPRs were grafted into homozygous (+/+) p53 male mice, fed a 4-HPR containing diet or a control diet and maintained until the status of tumor progression dictated sacrifice. Under these experimental conditions, treatment with 4-HPR did not have a significant effect on primary tumor wet weight for either p53 +/- or p53 -/- MPRs. For, p53 +/- MPRs the animals fed the 4-HPR diet had a slight improvement in survival and a significant reduction in the number of mesenteric metastases (P = 0.0477, t-test). Notably, in p53 +/- MPRs the incidence of metastasis to lumbar spine and sternum was 92% in the control animals compared to 54% in the 4-HPR treated animals (P = 0.035, chi2-test). In p53 -/- MPRs there was a trend toward a reduction in the number of soft tissue metastases to lung and liver in the 4-HPR group relative to the control diet group and a statistically significant reduction in the incidence of metastasis to bone was demonstrated in that 50% of control animals versus 30% of 4-HPR treated p53 -/- animals harbored bone metastases (P = 0 < 0.05, chi2-test). Cell lines were established from portions of the primary tumor and from selected metastatic deposits in each experimental group. Clonal analysis, by retroviral integration pattern, indicated increased clonal diversity in both the primary tumors and metastasis-derived cell lines from 4-HPR treated animals relative to the control animals. In vitro treatment with 4-HPR did not reveal discriminating differences between cell lines derived from primary tumors and bone metastases or control and treatment groups in regard to growth arrest or apoptotic responses. Overall these studies indicate limited anti-tumor and anti-metastatic activity in this highly aggressive in vivo mouse model of prostate cancer, yet 4-HPR treatment significantly suppressed the development of bone metastases in p53 +/- and p53 -/- MPRs revealing a novel and potentially clinically useful activity of this retinoid. Publication Types: Evaluation Studies PMID: 11467776 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 362: Cytometry. 2001 Jun 15;46(3):136-49. Distinctive patterns of Her-2/neu, c-myc, and cyclin D1 gene amplification by fluorescence in situ hybridization in primary human breast cancers. Janocko LE, Brown KA, Smith CA, Gu LP, Pollice AA, Singh SG, Julian T, Wolmark N, Sweeney L, Silverman JF, Shackney SE. Department of Human Genetics MCP/Hahnemann University, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, USA. Background: Human solid tumors undergo clonal evolution as they progress, but evidence for specific sequences of genetic changes that occur in individual tumors and are recapitulated in other tumors is difficult to obtain. Methods: Patterns of amplification of Her-2/neu, c-myc, and cyclin D1 were determined by fluorescence in situ hybridization (FISH) in relation to the presence of p53 dysfunction and ploidy in 60 primary human breast cancers. Results: We show that there are clusters of genophenotypic abnormalities that distinguish lobular breast cancers from nonlobular tumors; that cyclin D1 amplification occurs prior to the divergence of lobular breast cancers from nonlobular cancers; that p53 dysfunction, Her-2/neu amplification, and c-myc amplification are characteristic features of nonlobular breast cancers, but not of lobular breast cancers; and that the frequencies of amplification of all three oncogenes examined increase progressively with increasing aneuploidy, but that each gene exhibits a different profile of increasing amplification in relation to tumor progression. Early amplification of c-myc appears to be an especially prominent feature of hypertetraploid/hypertetrasomic tumors. Conclusions: The data suggest that in tumors containing multiple abnormalities, these abnormalities often accumulate in the same cells within each tumor. Furthermore, the same patterns of accumulation of multiple genophenotypic abnormalities are recapitulated in different tumors. PMID: 11449404 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 363: Braz J Med Biol Res. 2001 Jul;34(7):887-94. Expression of c-erbB-2, p53 and c-myc proteins in male breast carcinoma: Comparison with traditional prognostic factors and survival. Mourao Netto M, Logullo AF, Nonogaki S, Brentani RR, Brentani MM. Hospital do Cancer A.C. Camargo, San Paulo, Brasil. There are few data evaluating biological markers for men with breast cancer. The purpose of the present study was to analyze the expression of the oncogenes c-erbB-2 and c-myc and of the suppressor gene p53 by immunohistochemical techniques in archival paraffin-embedded tissue blocks of 48 male breast cancer patients, treated at the A.C. Camargo Cancer Hospital, Sao Paulo, SP, Brazil. The results were compared with clinicopathological prognostic features. Immunopositivity of c-erbB-2, p53 and c-myc was detected in 62.5, 16.7 and 20.8% of the cases analyzed, respectively. Estrogen and progesterone receptors were positive in 75 and 69% of the cases, respectively. Increasing staging was statistically associated with c-erbB-2 (P = 0.04) and weakly related to p53 positivity (P = 0.06). No significant correlation between specific survival rate (determined by the log rank test) and the molecular markers analyzed was found, whereas the number of compromised lymph nodes and advanced TNM (tumor, node, metastasis) staging were associated with diminished survival. PMID: 11449307 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 364: Mol Cell Biol. 2001 Aug;21(15):5063-70. Apoptosis triggered by Myc-induced suppression of Bcl-X(L) or Bcl-2 is bypassed during lymphomagenesis. Eischen CM, Woo D, Roussel MF, Cleveland JL. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. Enforced Bcl-2 expression inhibits Myc-induced apoptosis and cooperates with Myc in transformation. Here we report that the synergy between Bcl-2 and Myc in transforming hematopoietic cells in fact reflects a Myc-induced pathway that selectively suppresses the expression of the Bcl-X(L) or Bcl-2 antiapoptotic protein. Myc activation suppresses Bcl-X(L) RNA and protein levels in cultures of primary myeloid and lymphoid progenitors, and Bcl-X(L) and Bcl-2 expression is inhibited by Myc in precancerous B cells from Emu-myc transgenic mice. The suppression of bcl-X RNA levels by Myc requires de novo protein synthesis, indicating that repression is indirect. Importantly, the suppression of Bcl-2 or Bcl-X(L) by Myc is corrupted during Myc-induced tumorigenesis, as Bcl-2 and/or Bcl-X(L) levels are markedly elevated in over one-half of all lymphomas arising in Emicro-myc transgenic mice. Bcl-2 and/or Bcl-X(L) overexpression did not correlate with loss of ARF or p53 function in tumor cells, indicating that these two apoptotic pathways are inactivated independently. Therefore, the suppression of Bcl-X(L) or Bcl-2 expression represents a physiological Myc-induced apoptotic pathway that is frequently bypassed during lymphomagenesis. PMID: 11438662 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 365: Cancer Res. 2001 Jun 15;61(12):4910-5. c-myc/p53 interaction determines sensitivity of human colon carcinoma cells to 5-fluorouracil in vitro and in vivo. Arango D, Corner GA, Wadler S, Catalano PJ, Augenlicht LH. Albert Einstein Cancer Center, Oncology Department, Montefiore Medical Center, Bronx, New York 10467, USA. Colon carcinoma cells overexpress c-myc due to defective Wnt signaling, but only patients whose tumors have an amplified c-myc gene show improved disease-free and overall survival in response to 5-fluoruracil (5FU). Here we show that in two colon carcinoma cell lines that do not have an amplified c-myc gene but differ in their p53 status, high c-myc levels can be further elevated by introducing a c-myc expression vector. Whereas sensitivity to low serum-induced apoptosis was imposed on the parental lines independent of p53 status and was unaffected by further elevation of c-myc, sensitivity to 5FU-induced apoptosis was dependent on both the higher c-myc levels due to the expression vector and wild-type p53 function. The elevated c-myc levels led to higher c-myc transactivation activity in the p53 wild-type cell line, but not in the mutant p53 cell line. The requirement for both elevated c-myc and p53 for 5FU sensitivity was confirmed using antisense c-myc and pifithrin-alpha, a specific inhibitor of p53. Finally, the in vitro data predicted that only patients with both amplified c-myc and wild-type p53 in their primary tumors would be responsive to 5FU-based therapy, which was borne out by analysis of tumors from 135 patients entered into a Phase III clinical trial of 5FU-based adjuvant therapy. The data provide significant insight into mechanisms that establish colon tumor cell sensitivity to 5FU, clearly demonstrate the necessity of exercising caution in considering combining novel strategies that target elevated c-myc with standard 5FU-based therapy, and suggest alternative therapeutic strategies that target c-myc and/or p53 mutations in the treatment of colon cancer. PMID: 11406570 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 366: Mol Pharmacol. 2001 Jul;60(1):174-82. c-Myc down-regulation increases susceptibility to cisplatin through reactive oxygen species-mediated apoptosis in M14 human melanoma cells. Biroccio A, Benassi B, Amodei S, Gabellini C, Del Bufalo D, Zupi G. Experimental Chemotherapy Laboratory, Experimental Research Center, Regina Elena Cancer Institute, Rome, Italy. Our aim in this work was to define the role of c-Myc in the susceptibility to cisplatin [cis-diamminedichloroplatinum(II) (CDDP)] in human melanoma cells. Two M14 melanoma cell clones obtained by transfection and expressing six to ten times lower c-Myc protein levels than the parental cells and the control clone were employed. Analysis of survival curves demonstrates an increase in CDDP sensitivity in c-Myc low-expressing clones if compared with the control clone and the parental line. The enhanced sensitivity is unrelated to the impairment in enzymatic DNA repair activity. Cell cycle analysis demonstrates that although the control clone is able to completely recover from the CDDP-induced S-G(2)/M block, this arrest is prolonged in c-Myc low-expressing clones and a fraction of cells undergoes apoptosis. Although no changes in P53, Bax, Bcl-2, and Bcl-x(L/S) protein levels are observed, apoptosis is associated with the formation of reactive oxygen species (ROS), activation of caspase-1, caspase-3 and cleavage of the specific caspase substrate poly-ADP-ribose polymerase. The use of the antioxidant N-acetyl cysteine and caspase inhibitors prevents CDDP-induced apoptosis in c-Myc low-expressing clones, demonstrating that ROS, caspase-1, and caspase-3 are required for apoptotic cell death. Moreover, ROS generation depends on caspase-1-like activation because the Ac-YVAD-cho inhibitor abrogates CDDP-induced ROS in the c-Myc low-expressing clones. PMID: 11408612 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 367: Semin Cancer Biol. 2001 Jun;11(3):261-8. Genetic dissection of melanoma pathways in the mouse. Yang FC, Merlino G, Chin L. Department of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Mayer 448, Boston, MA 02115, USA. The frequent loss of the INK4a/ARF locus, encoding for both p16(INK4a)and p19(ARF)in human melanoma, raises the question as to which INK4a/ARF gene product functions to suppress melanoma-genesis in vivo. Studies in the mouse have shown that activated RAS mutation can cooperate with INK4a(Delta 2/3)deficiency (null for both p16(INK4a)and p19(ARF)) to promote development of melanoma, and these melanomas retain wild-type p53. Given the functional link between p19(ARF)and p53, we have now shown that activated RAS can also cooperate with p53 deficiency to produce melanoma in the mouse. Moreover, genome-wide analysis of RAS-induced p53 mutant melanomas reveals alterations of key components governing RB-regulated G1/S transition, such as c-Myc. These experimental findings suggest that both RB and p53 pathways function to suppress melanocyte transformation in vivo in the mouse. Copyright 2001 Academic Press. Publication Types: Review Review, Tutorial PMID: 11407950 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 368: Int J Radiat Biol. 2001 Jun;77(6):687-94. Comment in: Int J Radiat Biol. 2002 May;78(5):441-3. Int J Radiat Biol. 2002 May;78(5):443-5. Int J Radiat Biol. 2003 May;79(5):367-70; author reply 371-4. Microsatellite instability in acute myelocytic leukaemia developed from A-bomb survivors. Nakanishi M, Tanaka K, Takahashi T, Kyo T, Dohy H, Fujiwara M, Kamada N. Department of Cancer Cytogenetics, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi l-2-3, Minami-ku, Hiroshima 734-8553, Japan. PURPOSE: Genetic alterations, including microsatellite instability (MSI), are ultimate steps toward malignant process. To investigate MSI in A-bomb survivors, leukaemic cells were analysed from 13 acute myelocytic leukaemia patients with a history of radiation exposure and also in 12 de novo patients. MATERIALS AND METHODS: To assess the microsatellite changes, a fluorescent system in 10 loci (BAT40, D3S643, D5S107, IRF1, MYC, D9S171, WT1, TP53, DM, D17S855) was used. RESULTS: MSI analysis revealed a high frequency of multiple microsatellite changes in the exposed patients (84.6%) compared with non-exposed patients (8.3%). There was a significant difference (p < 0.001) between the two groups. CONCLUSIONS: These analyses clearly demonstrate that leukaemic cells from heavily exposed patients contain a number of genetic instabilities that may strongly influence the development of leukaemia among people exposed to the Hiroshima A-bomb radiation. PMID: 11403708 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 369: Cell Biol Int. 2001;25(5):411-20. Altered matrix metalloproteinase expression associated with oncogene-mediated cellular transformation and metastasis formation. Baruch RR, Melinscak H, Lo J, Liu Y, Yeung O, Hurta RA. Department of Laboratory Medicine and Pathobiology, St Michael's Hospital, University of Toronto, Toronto, Ontario, M5B 1A6, Canada. Matrix metalloproteinase expression was examined in a series of mammalian cell lines of varying degrees of malignant progression. The expression of MMP-2 and MMP-9 was found to correlate with ras-mediated cellular transformation and as a function of malignant potential. Altered MMP-2 and MMP-9 expression was found to correlate also in other oncogene transformed cell lines and the level of expression of both MMP-2 and MMP-9 correlated with metastatic potential. Increased expression of both MMP-2 and MMP-9 was also found in cells which constitutively over-express MAP kinase kinase suggesting that one of the consequences of the persistent activation of the MAP kinase pathway is elevated expression of MMP-2 and MMP-9. Additionally, this study demonstrated a correlation between the expression of MMP-3 (stromelysin-1) and the level of ras expressed in cells and with the cells' ability to form tumors and with malignant potential. The existence of a novel 80 kDa caseinase activity which correlates with ras expression and the ability of the cell to form tumors was also demonstrated. The growth status of transformed cells was also found to be important in determining the expression of MMP-2 mRNA but not MMP-9 mRNA expression, and this expression was cell-type specific. This study also demonstrates that oncogenes can interact to influence and to determine the nature of the matrix metalloproteinases expressed and that this interaction results in a tumorigenic phenotype and, most importantly, contributes to the metastatic phenotype. Alterations in the expression and the regulation of MMPs, particularly MMP-2 and MMP-9, constitute an integral part of the altered growth regulatory program found within transformed cells and in particular, in transformed cells capable of malignant progression. PMID: 11401328 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 370: Anticancer Res. 2001 Mar-Apr;21(2B):1321-5. Copy number of cancer genes predict tumor grade and survival of pancreatic cancer patients. Nagy A, Kozma L, Kiss I, Ember I, Takacs I, Hajdu J, Farid NR. Department of Pathology, University Medical School of Debrecen, Hungary. Pancreatic cancer is on the increase. While means of early diagnosis are being sought, it continues to present late. Prognostication is based on patient and tumor characteristics, including expression or mutation of cancer-related genes. Few studies have examined the impact of the amplification of these genes on the outcome of pancreatic cancer. We have now used a non-radioisotopic slot-blot technique to relate gene copy numbers of p53, c-myc and K-ras to tumor grade and survival. Outcomes were corrected for patient characteristics, tumor location and TNM staging. The Kaplan-Meier test for likelihood of survival showed that increase in copy number of the two oncogenes and loss of p53 were associated with non-significant reduction in survival. When these variations in cancer gene copy numbers were, however, examined by logistic regression analysis in the context of patient and tumor characteristics, survival was negatively related to K-ras amplification (p = 0.0291). Tumor grade, but not survival was positively related to loss of p53 gene copy (p = 0.0131) as well as c-myc amplification (p = 0.0248). Thus using a simple non-radioisotopic technique for the detection of cancer gene copy number in association with patients and disease characteristics, we could predict survival on the one hand and tumor behavior on the other. Such information could be used to plan initial and follow-up therapy. PMID: 11396207 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 371: Am J Pathol. 2001 Jun;158(6):2067-77. p53 cellular localization and function in neuroblastoma: evidence for defective G(1) arrest despite WAF1 induction in MYCN-amplified cells. Tweddle DA, Malcolm AJ, Cole M, Pearson AD, Lunec J. Cancer Research Unit, The Medical School, University of Newcastle, Newcastle-upon-Tyne, United Kingdom. d.a.tweedle@newcastle.ac.uk This study investigated the hypothesis that p53 accumulation in neuroblastoma, in the absence of mutation, is associated with functional inactivation, which interferes with downstream mediators of p53 function. To test this hypothesis, p53 expression, location, and functional integrity was examined in neuroblastoma by irradiating 6 neuroblastoma cell lines and studying the effects on p53 transcriptional function, cell cycle arrest, and induction of apoptosis, together with the transcriptional function of p53 after irradiation in three ex vivo primary, untreated neuroblastoma tumors. p53 sequencing showed five neuroblastoma cell lines, two of which were MYCN-amplified, and that all of the tumors were wild-type for p53. p53 was found to be predominantly nuclear before and after irradiation and to up-regulate the p53 responsive genes WAF1 and MDM2 in wild-type p53 cell lines and a poorly-differentiated neuroblastoma, but not a differentiating neuroblastoma or the ganglioneuroblastoma part of a nodular ganglioneuroblastoma in short term culture. This suggests intact p53 transcriptional activity in proliferating neuroblastoma. Irradiation of wild-type p53 neuroblastoma cell lines led to G(1) cell cycle arrest in cell lines without MYCN amplification, but not in those with MYCN amplification, despite induction of WAF1. This suggests MYCN amplification may alter downstream mediators of p53 function in neuroblastoma. PMID: 11395384 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 372: FASEB J. 2001 Jun;15(8):1404-6. Lack of p53 accelerates hepatocarcinogenesis in transgenic mice constitutively overexpressing c-myc in the liver. Klocke R, Bartels T, Jennings G, Brand K, Halter R, Strauss M, Paul D. Fraunhofer Institute of Toxicology and Aerosol Research, Department of Cell Biology, D-30625 Hannover, Germany. rainer.klocke@ingenium-ag.com PMID: 11387238 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 373: J Steroid Biochem Mol Biol. 2001 Jan-Mar;76(1-5):105-17. Hormonal regulation of tumor suppressor proteins in breast cancer cells. Moudgil VK, Dinda S, Khattree N, Jhanwar S, Alban P, Hurd C. Department of Biological Sciences and the Center for Biomedical Research, Oakland University, Rochester, MI 48309-4476, USA. moudgil@oakland.edu This laboratory is studying hormonal regulation of tumor suppressor proteins, p53 and retinoblastoma (pRB). Estrogen receptor and progesterone receptor positive human breast cancer cell lines, T47D and MCF-7, were utilized for determining influence of hormonal and antihormonal agents on the level of expression of p53, state of phosphorylation of pRB, and rate of cell proliferation. The expression of p53 in T47D cells grown for 4-5 days in culture medium containing charcoal-treated (stripped) fetal bovine serum declined gradually to 10% of the level seen in control (whole serum, non charcoal-treated) groups. Supplementation of culture medium containing stripped serum with 0.1-1 nM estradiol (E(2)) restored p53 to its level seen in the control within 6-24 h. Under above conditions, treatment of cells with R5020 or RU486 reduced (15-30%) the level of p53. Incubation of cells in E(2)-containing growth medium caused cell proliferation and hyperphosphorylation of pRB; the latter effect was seen maximally between 24-72 h. The E(2)-induced hyperphosphorylation of pRB and increase in the level of p53 were sensitive to the presence of ICI and 4-hydroxy tamoxifen (OHT). T47D and MCF-7 cells were also transiently transfected with a P1CAT reporter plasmid containing c-Myc responsive element and the levels of chloramphenicol acetyltransferase (CAT) activity were observed in response to various treatments. E(2) and OHT caused P1CAT induction as seen by increased CAT activity: E(2) caused an endogenous increase in the expression of an ICI-sensitive c-Myc form. These data suggest that estrogen upregulates p53 expression while progesterone downregulates this process. Further, E(2) regulates p53 level and pRB activity in a coordinated manner. PMID: 11384868 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 374: Cancer Genet Cytogenet. 2001 Mar;125(2):81-6. The influence of cytogenetic aberrations on gene replication in chronic lymphocytic leukemia patients. Amiel A, Elis A, Sherker S, Gaber E, Manor Y, Fejgin MD. Genetic Institute and the Department of Medicine, Meir Hospital and Sackler Faculty of Medicine, Tel Aviv University, Kfar-Saba 44281, Tel Aviv, Israel. Chronic lymphocytic leukemia (CLL) is the most common leukemia in humans, with the major cytogenetic aberrations of trisomy 12 and deletion of 13q14. This study examined the influence of these aberrations on general gene replication. The study group included three subgroups: (1) 15 CLL patients, (2) 4 CLL patients with trisomy 12, (3) 3 CLL patients with deletions in 13q14. Five healthy individuals served as a control group. Monocolor fluorescence in situ hybridization (FISH) with probes for c-myc, HER-2/neu, and p53 was applied to lymphocyte nuclei for the evaluation of replication timing. Asynchronous replication (SD) rate was significantly higher in all CLL patients (P < 0.01) when compared to the control group and was even higher in the group of CLL patients with trisomy 12 and 13q14 deletion (P < 0.01). The asynchrony rate was significantly higher in cells with trisomy 12 for all three probes analyzed, compared to "healthy" cells in the same patients (P < 0.001). To conclude, in CLL patients with a chromosomal aberration such as trisomy 12 and 13q14 deletion we were able to demonstrate a high rate of asynchrony of replication. The high correlation between cells with trisomy 12 and SD pattern could reflect direct influence of the aberration on gene replication and cell cycle control. PMID: 11369050 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 375: Arch Biochem Biophys. 2001 Apr 15;388(2):243-52. Rb dephosphorylation and suppression of E2F activity in human breast tumor cells exposed to a pharmacological concentration of estradiol. Gewirtz DA, Di YM, Randolph JK, Jain PT, Valerie K, Bullock S, Nath N, Chellappan SP. Department of Pharmacology, Toxicology and Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond, USA. gewirtz@hsc.vcu.edu This report characterizes the influence of a pharmacological concentration of estradiol on growth arrest and cell death in MCF-7 breast tumor cells, with a focus on elements of the Rb-E2F cell-cycle regulatory pathway. Continuous exposure of MCF-7 breast tumor cells to 100 microM estradiol produces a marked reduction in the G1 and S phase populations and a corresponding increase in the G2/M population within 24 h; after 48 h, accumulation of cells in G1 becomes evident while after 72 h the cells appear to be equally distributed between the G1 and G2/M phases. The accumulation of cells in G1 is temporally associated with dephosphorylation of the Rb protein and suppression of E2F activity. Estradiol also produces an initial burst of cell death with loss of approximately 40% of the tumor cell population within 24 h; however, there is no tangible evidence for the occurrence of apoptosis based on terminal transferase end-labeling of DNA, DNA fragmentation analysis by alkaline unwinding, cell-cycle analysis or cell morphology. In addition to the lack of caspase-3 in MCF-7 cells, the absence of apoptosis could be related, at least in part, to the fact that estradiol promotes a rapid reduction in levels of the E2F-1 and Myc proteins. Overall, these studies are consistent with the concept that alterations in the levels and/or activity of the E2F family of proteins as well as proteins interacting with the E2F family may influence the nature of the antiproliferative and cytotoxic responses of the breast tumor cell. PMID: 11368161 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 376: Oncogene. 2001 Apr 19;20(17):2171-7. p14ARF homozygous deletion or MDM2 overexpression in Burkitt lymphoma lines carrying wild type p53. Lindstrom MS, Klangby U, Wiman KG. Karolinska Institute, Department of Oncology-Pathology, Cancer Center Karolinska (CCK), Karolinska Hospital, SE-171 76 Stockholm, Sweden. The hallmark of Burkitt lymphoma (BL) is a constitutively activated c-myc gene that drives tumor cell growth. A majority of BL-derived cell lines also carry mutant p53. In addition, the p16INK4a promoter is hypermethylated in most BL biopsies and BL cell lines, leading to silencing of this gene. Activation of c-myc and/or cell cycle dysregulation can induce ARF expression and p53-dependent apoptosis. We therefore investigated the p14ARF-MDM2-p53 pathway in BL cell lines. p14ARF was expressed and localized to nucleoli in all BL carrying mutant p53. Three out of seven BL carrying wt p53 had a homozygous deletion of the CDKN2A locus that encodes both p14ARF and p16INK4a. Three BL carrying wild type p53 retained the CDKN2A locus and overexpressed MDM2. DNA sequencing revealed a point mutation in CDKN2A exon 2 in one of these BL, Seraphine. However, this point mutation did not affect p14ARF's nucleolar localization or ability to induce p53. The Bmi-1 protein that negatively regulates the p14ARF promoter and co-operates with c-myc in tumorigenesis was expressed at low to moderate levels in all BL analysed. Our results indicate that inactivation of the ARF-MDM2-p53 pathway is an essential step during the development of Burkitt lymphoma, presumably as a mechanism to escape c-myc induced apoptosis. PMID: 11360201 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 377: Am J Hematol. 2001 Jun;67(2):84-92. Erratum in: Am J Hematol 2001 Aug;67(4):279. p53, Mdm2, and c-Myc overexpression is associated with a poor prognosis in aggressive non-Hodgkin's lymphomas. Pagnano KB, Vassallo J, Lorand-Metze I, Costa FF, Saad ST. Hemocentro/Department of Internal Medicine, State University of Campinas, Campinas, SP, Brazil. The expression of p53, p21/WAF-1, Mdm2, c-Myc, and proliferating cell nuclear antigen (PCNA) proteins was examined by the immunohistochemistry of paraffin-embedded tissues of 62 patients with aggressive non-Hodgkin's lymphomas (NHL) and correlated to clinical data. Expression of p53, p21/WAF-1, Mdm2, and c-Myc protein was observed in 17 out of 62 cases (30%), 25 out of 60 (42%), 13 out of 44 (30%), and 39 out of 51 (76.5%), respectively. The p53+/p21WAF-1 phenotype, which is more frequently found in p53 mutations, was associated with a worse overall survival (P = 0.04) and with a lower rate of complete response (CR) (PF = 0.01). p53 and c-Myc negative expression was related to a better response to chemotherapy (PF = 0.005 and 0.035, respectively). The expression of p53, c-Myc, and Mdm2 was related to a shortened overall survival (P < 0.001, 0.05, and 0.037, respectively), suggesting that the expression of these proteins could be associated with a poor outcome in these patients. Copyright 2001 Wiley-Liss, Inc. PMID: 11343379 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 378: Leuk Lymphoma. 2001 Mar;41(1-2):47-53. Genetic alterations in primary mediastinal B-cell lymphoma: an update. Scarpa A, Moore PS, Rigaud G, Menestrina F. Department of Pathology-Section of Anatomical Pathology, Universita di Verona, Italy. scarpa@anpat.univr.it Primary mediastinal B-cell lymphoma (PMBL) is a distinct clinical entity among non-Hodgkin's lymphoma. The malignancy has received little attention from a standpoint of basic research due in part to its rarity. However, based on recent studies consistent trends are beginning to emerge regarding the molecular and chromosomal alterations commonly observed in this disease. By both CGH and AP-PCR, genetic gains involving chromosomes 2, 5, 7, 9p, 12, and Xq are among the most frequently observed events. From a molecular standpoint, alterations in the c-myc, p16(INK4) and p53 genes have been observed in up to 30% of cases. This information along with the well-established histological, immunological, and clinical features should convince the few remaining disbelievers that PMBL is a distinct pathological entity among non-Hodgkin's lymphomas. Publication Types: Review Review, Tutorial PMID: 11342356 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 379: Am J Clin Pathol. 2000 Dec;114(6):983-5. Comment on: Am J Clin Pathol. 1996 Oct;106(4):522-34. Am J Clin Pathol. 2000 Apr;113(4):512-8. Coexpression of c-Myc and p53 as a marker of survival time. Vollmer RT. Publication Types: Comment Letter PMID: 11338487 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 380: Oral Oncol. 2001 Jun;37(4):386-92. Establishment of an oral squamous cell carcinoma cell line (NOS-1) exhibiting amplification of the erbB-1 oncogene and point mutation of p53 tumor suppressor gene: its biological characteristics and animal model of local invasion by orthotopic transplantation of the cell line. Ji ZW, Oku N, Umeda M, Komori T. Department of Oral and Maxillofacial Surgery, Kobe University School of Medicine 7-5-1 Kusunoki-Cho, Chuo-Ku, 650-0017, Kobe, Japan. We established a new cancer cell line, NOS-1, which was derived from a human oral primary squamous cell carcinoma. Geneticin treatment was adopted to eliminate contaminating fibroblasts and to enrich tumor cells in the early stage of the culture. The NOS-1 cells showed epithelial morphological features with light and electron microscopy, and immunohistochemical analysis confirmed their epithelial origin. Overexpression of mutant p53 protein, a p53 point mutation at codon 248 with transition from CGG to TGG, and amplification of the erbB-1 oncogene/epidermal growth factor receptor gene were also observed in NOS-1 cells. The NOS-1 cells formed tumors in nude mice when transplanted subcutaneously into their backs. Further, they were transplantable orthotopically in the tongues of nude mice, and the transplanted tumors in the tongue showed diffuse invasion without forming capsules. The NOS-1 cells were useful for elucidating the mechanism involving p53 inactivation and erbB-1 oncogene amplification, as well as treatment of oral cancer. PMID: 11337272 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 381: Apoptosis. 2001 Feb-Apr;6(1-2):133-7. Inactivation of Myc-induced p53-dependent apoptosis in human tumors. Henriksson M, Selivanova G, Lindstrom M, Wiman KG. Microbiology and Tumor Biology Center, Karolinska Institutet, Stockholm, Sweden. The Myc family of oncoproteins promote cell growth and are frequently overexpressed in human tumors. However, Myc can also trigger cell death by apoptosis. This is at least in part mediated via the ARF-p53 pathway. Myc activation leads to a selection for inactivation of ARF or p53, allowing cell survival and tumor progression. Restoration of p53-dependent apoptosis by various means is an attractive approach for new cancer therapy. Publication Types: Review Review, Tutorial PMID: 11321036 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 382: Int J Radiat Oncol Biol Phys. 2001 May 1;50(1):13-8. Apoptosis and bcl-2 expression as predictors of survival in radiation-treated non-small-cell lung cancer. Hwang JH, Lim SC, Kim YC, Park KO, Ahn SJ, Chung WK. Department of Internal Medicine, Chonnam National University Medical School, 8 Hak-Dong, Dong-ku, Kwangju, 501-757, South Korea. OBJECTIVES: We assessed the role of apoptosis and the expression of bcl-2, p53, and c-myc oncoproteins in pretreatment histologic specimens as a predictor of response to radiation therapy and survival in non-small-cell lung cancer (NSCLC) patients. METHODS: Pretreatment biopsy specimens of 68 patients with NSCLC (62 squamous cell carcinoma, 6 adenocarcinoma) were stained with hematoxylin and eosin. From 5 high-powered fields, the apoptotic index (AI) was calculated as the ratio of apoptotic tumor cells to the total number of tumor cells. Bcl-2, p53, and c-myc oncoprotein expression was detected by immunohistochemical staining. RESULTS: Twenty-nine cases showed partial or complete remission, whereas 39 showed no response. AI ranged from 0.2 to 12.0% (mean +/- SD; 4.3 +/- 2.6%, median 4.0%). There was no difference in AI between responders (4.0 +/- 2.3) and nonresponders (4.5 +/- 2.8, p > 0.05). However, in the responders, AI was correlated with the degree of change in tumor volume (r = 0.41, p < 0.05). In an analysis of 53 subjects who survived more than 1 month after the completion of radiation therapy, the patients with a higher AI (n = 27, MST = 22.8 m) survived longer than those with a lower AI (n = 26, MST = 9.2, log-rank, p = 0.03). Patients expressing bcl-2 had poorer survival (n = 22, MST = 6.0 m) than patients without bcl-2 (n = 31, 22.8 m, p < 0.003). According to multivariate analysis, three variables, bcl-2 expression, AI, and response to radiation, were independent prognostic factors for survival. CONCLUSION: A low level of spontaneous apoptosis and expression of apoptosis blocking bcl-2 protein in pretreatment histology predict a poor prognosis for radiation-treated NSCLC patients. PMID: 11316541 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 383: Oncogene. 2001 Jan 18;20(3):295-302. Runx2: a novel oncogenic effector revealed by in vivo complementation and retroviral tagging. Blyth K, Terry A, Mackay N, Vaillant F, Bell M, Cameron ER, Neil JC, Stewart M. Molecular Oncology Laboratory, University of Glasgow Veterinary School, Bearsden, Glasgow, G61 1QH, UK. The Runx2 (Cbfa1, Pebp2alphaA, Aml3) gene was previously identified as a frequent target for transcriptional activation by proviral insertion in T-cell lymphomas of CD2-MYC transgenic mice. We have recently shown that over-expression of the full-length, most highly expressed Runx2 isoform in the thymus perturbs T-cell development, leads to development of spontaneous lymphomas at low frequency and is strongly synergistic with Myc. To gain further insight into the relationship of Runx2 to other lymphomagenic pathways, we tested the effect of combining the CD2-Runx2 transgene either with a Pim1 transgene (E(mu)-Pim1) or with the p53 null genotype, as each of these displays independent synergy with Myc. In both cases we observed synergistic tumour development. However, Runx2 appeared to have a dominant effect on the tumour phenotype in each case, with most tumours conforming to the CD3(+), CD8(+), CD4(+/-) phenotype seen in CD2-Runx2 mice. Neonatal infection of CD2-Runx2 mice with Moloney murine leukaemia virus (Moloney MLV) also led to a dramatic acceleration of tumour onset. Analysis of known Moloney MLV target genes in these lymphomas showed a high frequency of rearrangement at c-Myc or N-Myc (82%), and a significant number at Pim1 or Pim2 (23%), and at Pal1/Gfi1 (18%). These results indicate that Runx2 makes a distinct contribution to T-cell lymphoma development which does not coincide with any of the oncogene complementation groups previously identified by retroviral tagging. PMID: 11313958 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 384: Oncogene. 2001 Mar 8;20(10):1164-75. Expression of Mad1 in T cells leads to reduced thymic cellularity and impaired mitogen-induced proliferation. Rudolph B, Hueber AO, Evan GI. Imperial Cancer Research Fund, PO Box 123, 44 Lincoln's Inn Fields, London WC2A 3PX, UK. To investigate Mad1 function in vivo, transgenic mice were generated that express a Mad1 transgene in T lineage cells under the control of the proximal lck promoter. Thymus size in lck-Mad1 transgenic mice is drastically reduced although representation of the various thymocyte sub populations appears normal. To investigate more closely any effects of Mad1 expression on thymocytes, we examined thymic selection using MHC class I-restricted H-Y-TCR transgenic mice. Mad1 expression in vivo reduces the efficiency of positive selection. Furthermore, thymocytes and splenic T cells from lck-Mad1 transgenic mice display a profound proliferative defect in response to activation with either PMA/Ionomycin or immobilized anti-CD3/CD28 antibody. This proliferative defect is not reversed by addition of exogenous IL-2 and is p53-independent. The growth inhibition caused by Mad1 is overcome by expression of active c-Myc. PMID: 11313860 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 385: Arch Oral Biol. 2001 Jun;46(6):545-55. Amplification of extracellular matrix and oncogenes in tat-transfected human salivary gland cell lines with expression of laminin, fibronectin, collagens I, III, IV, c-myc and p53. McArthur CP, Wang Y, Heruth D, Gustafson S. Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, 650 E 25th Street, Kansas City, MO 64108, USA. mcarthur@umkc.edu Considerable progress has been made in the transfer of foreign genes into salivary glands in vivo using adenovirus vectors in rats. In an attempt to avoid the transient expression inherent, when using these vectors, retroviral vectors and human cell lines where used here in attempt to develop an in vitro model of HIV-associated salivary gland disease. The HIV-1-tat protein is increasingly implicated in the pathogenesis of the AIDS through altering the expression of strategic cellular genes. The purpose of this study was to transfect human salivary gland (HSG) cell lines in vitro, with the pHIV-1/LTR-tat plasmid, and examine the effect of tat on expression of matrix and basement membrane genes known to be important in the pathogenesis of salivary gland disease. HSG cells were transfected with HIV-1-tat plasmid by the lipofection method. Transfection was confirmed by polymerase chain reaction (PCR) and Southern blot, which verified that tat-specific DNA was present. Tat-mRNA was analysed by Northern blotting and quantified by reverse transcriptase polymerase chain reaction (RT-PCR) to demonstrate its expression. Numerous clones were found to contain integrated tat DNA sequences and analysis of mRNA showed stable expression of tat-specific RNA. Further analysis of mRNA expression for various marker proteins important in HIV pathogenesis showed that the HSG cell line transfected with HIV-1-tat, was associated with significant induction of mRNA expression for extracellular matrix protein. Tat-amplified transcription of the major basement membrane protein laminin, as well as of fibronectin, collagen I and III, and c-myc oncogene was demonstrated. Conversely, expression of p53 suppressor gene mRNA was reduced. Post-transfection expression of collagen IV was erratic and inconclusive. It was concluded that the presence of HIV-tat in this in vitro model of salivary ductal epithelial cell model alters the mRNA expression of several matrix, basement membrane and oncoproteins known to be involved in HIV pathogenesis. These cell lines provide a useful system for studying the role of tat in the immunopathogenesis of HIV-associated salivary gland disease. PMID: 11311202 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 386: Br J Haematol. 2001 Mar;112(4):863-73. Acquired immunodeficiency syndrome-related systemic non-Hodgkin's lymphoma. Bower M. Department of Oncology, Chelsea & Westminster Hospital, 369 Fulham Road, London SW10 9NH, UK. m.bower@ic.ac.uk Publication Types: Review PMID: 11298581 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 387: Cancer Lett. 2001 May 10;166(1):89-94. Quick quantitative analysis of gene dosages associated with prognosis in neuroblastoma. Tajiri T, Tanaka S, Shono K, Kinoshita Y, Fujii Y, Suita S, Ihara K, Hara T. Department of Pediatric Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, 812-8582, Fukuoka, Japan. The amplification of the N-myc gene and a gain of the chromosome 17q arm correlate with an unfavorable outcome in patients with neuroblastoma. In this study, we determined the gene dosage of the N-myc gene (located at 2p24) and Survivin gene (located at 17q25) using the p53 gene (located at 17p13) as the internal control gene by the TaqMan polymerase chain reaction (PCR)-based gene dosage analysis in 25 neuroblastoma samples. Based on the assumption that the gene dosages of each gene of a normal individual lymphocytes are 1.0, 11 of the 25 cases with a corrected gene dosage of N-myc (N-myc/p53) of more than 2.0 had a more unfavorable prognosis than the 14 cases with a N-myc gene dosage of less than 2.0 (5-year survival rate: 18 vs. 71%, P<0.01). Ten of 25 cases with a corrected Survivin gene dosage (Survivin/p53) of more than 2.0 had a more unfavorable prognosis than the 15 cases with a Survivin gene dosage of less than 2.0 (5-year survival rate: 10 vs. 67%, P<0.01). This quantitative PCR system is considered to be useful for quickly and accurately evaluating the degree of malignancy of neuroblastoma in order to select the optimal treatment. PMID: 11295291 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 388: Oncol Rep. 2001 May-Jun;8(3):557-61. Abnormal expression of pan-ras, c-myc and tp53 in squamous cell carcinoma of cervix: correlation with HPV and prognosis. Ngan HY, Cheung AN, Liu SS, Cheng DK, Ng TY, Wong LC. Department of Obstetrics and Gynaecology, Professorial Block, Queen Mary Hospital, Hong Kong. hysngan@hkucc.hku.hk The aim of this study is to assess, in squamous cell carcinoma of the cervix, the expression of pan-ras, c-myc and tp53 at protein level using an immunohistochemical (IHC) staining method. One hundred and seven patients with squamous cell carcinoma of the cervix were recruited. Fifty-four patients were of stage 1B/2A and 53 were of stage 2B and above. Positive IHC stainings of pan-ras, c-myc and tp53 proteins were detected in 80.4%, 32.7% and 25.2% of cases, respectively. No significant correlation between overexpression of pan-ras and c-myc was detected. However, significantly higher percentages of overexpression of c-myc was found in association with overly expressed tp53 samples (p = 0.014). Human papillomavirus (HPV) was detected in 77.6% of cancers. HPV 16/18 was detected in 72% of cancers. Overexpression of pan-ras and c-myc had no correlation with HPV detection and stage. However, higher percentages of overexpression of tp53 were found in early stage disease (p = 0.017) and in HPV 16/18 positive tumors (p = 0.006). Overexpression of pan-ras, c-myc and tp53 alone or in more than one oncogenes had no prognostic significance on survival. PMID: 11295080 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 389: J Biol Chem. 2001 Apr 13;276(15):12449-53. Epub 2001 Jan 16. Role of p53 in HER2-induced proliferation or apoptosis. Casalini P, Botta L, Menard S. Molecular Targeting Unit, Department of Experimental Oncology, Istituto Nazionale Tumori, 20133 Milano, Italy. HER2 oncogene overexpression has been associated either with proliferation or differentiation and apoptosis. The role of p53 on these different chances was investigated. Wild type (wt) p53-IGROV1 cells showed growth inhibition and apoptosis after HER2 transfection, whereas no anti-proliferative effect was observed in its mutated p53 sub-line unless wt p53 was cotransfected with HER2. Stable HER2 transfectants derived from wt p53 line treated with heregulin-beta1 or epidermal growth factor showed a decrease in proliferation due to a G(2)/M cell cycle block despite normal mitogen-activated protein kinase activation. In these HER2 transfectants, c-Myc and p53 expression were increased, whereas MDM2 was dramatically down-modulated. By contrast, growth factors stimulation of HER2 transfectants with mutated-p53 induced progression through the cell cycle. Together, our data point to a regulatory role for p53 in HER2 signaling. PMID: 11278558 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 390: Crit Rev Eukaryot Gene Expr. 2000;10(3-4):273-80. Regulation of apoptosis by E1A and Myc oncoproteins. Breckenridge DG, Shore GC. Department of Biochemistry, McGill University, Montreal, Quebec, Canada. E1A and c-myc are oncogenes that can deregulate the cell cycle and promote transformation under conditions where normal cell-cycle checkpoints are inactivated. In situations where cell-cycle checkpoints are intact, the E1A and c-Myc proteins potently induce apoptosis, a property that is believed to be the end result of a cellular response to uncontrolled growth-promoting signals. p53 is a key regulator of E1A and c-myc-induced apoptosis and, together with the oncoproteins, may transcriptionally activate numerous genes whose products influence, or are themselves, members of the core apoptotic machinery. The upstream signaling events and the ultimate apoptotic pathways activated by E1A and c-Myc are discussed in this review. Publication Types: Review Review, Tutorial PMID: 11272469 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 391: Zhonghua Jie He He Hu Xi Za Zhi. 1998 Jan;21(1):23-5. [Studies on genes associated with biologic behavior in human lung cancer] [Article in Chinese] Bai L, Sun Y, Li S. Cancer Institute and Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100021. OBJECTIVE: To study alteration of several genes in the process of primary lung cancer. METHODS: A series of 59 lung cancer specimens were analyzed for p53, myc oncogene family and mdrl gene by DNA/PCR sequencing, immunohistochemistry and RT-PCR methods. RESULTS: p53 mutation or/and protein accumulation were found in 37 of 57(65%) cases. Overexpression of myc family oncogenes and mdr1 gene were 27/46 (59%) and 15/48 (31%), respectively. The results also showed that there was no significant correlation between p53 alteration and tumor size, metastasis, stage and relapse, but there was a significant correlation between overexpression of myc family oncogene and these factors. Overexpression of mdrl gene was detected in NSCLC, especially in adenocarcinoma, and was not associated with metastasis and stage of lung cancer. It was also found that aberration of both p53 and myc family oncogenes occurred in 19/30(63%) cases; the relapse rate was 76%. Both overexpression of mdrl and myc gene was 62%; the relapse rate was 83%. CONCLUSION: p53, myc and mdrl genes in cooperation may be involved in the process of lung cancer, but prognostic determinant is myc gene overexpression. PMID: 11263295 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 392: J Cancer Res Clin Oncol. 2001;127(3):173-9. Effect of the nonsteroidal anti-inflammatory drug indomethacin on proliferation and apoptosis of colon carcinoma cells. Kralj M, Kapitanovic S, Kovacevic D, Lukac J, Spaventi S, Pavelic K. Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka c. 54, 10000 Zagreb, Croatia. PURPOSE: Nonsteroidal anti-inflammatory drugs lower the incidence of and mortality from colon cancer. In this paper, we present the effect of indomethacin on growth inhibition and alterations in the expression of several genes involved in cell cycle and apoptosis in CaCo-2 colon adenocarcinoma cells. METHODS: We used the MTT test to evaluate the effect of indomethacin on the proliferation rate of colon cancer and normal fibroblast cells in vitro. The expression of c-myc oncoprotein and p53 and p27 suppressor proteins was examined using the immunocytochemical method. RESULTS: We have shown that indomethacin reduces the proliferation rate of CaCo-2 colon cancer cells (up to 60% at the concentration of 4 x 10(-4) M), alters their morphology, and induces cell death by apoptosis. The most pronounced inhibitory effect was observed at the concentration of 6 x 10(-4) M where the growth was completely suppressed. However, the growth of normal fibroblasts (Hef 522) was much less inhibited (about 30% of inhibition at the concentration of 6 x 10(-4) M). Indomethacin reduces the proliferation rate and induces apoptosis in CaCo-2 colon cancer cells through enhanced expression of c-myc, p53, and p27 proteins. CONCLUSIONS: This is the first report about p27-increased expression in colon carcinoma cells induced by indomethacin treatment. Increased expression of p27 represents a new mechanism of apoptosis in cells treated with NSAIDs (indomethacin). This effect probably contributes to the anti-proliferative effect on colon cancer cells in vitro. PMID: 11260862 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 393: J Pharmacol Exp Ther. 2001 Apr;297(1):57-68. Matrix metalloproteinase inhibitors cause cell cycle arrest and apoptosis in glomerular mesangial cells. Daniel C, Duffield J, Brunner T, Steinmann-Niggli K, Lods N, Marti HP. Division of Nephrology and Hypertension, University of Bern, CH-3010 Bern, Switzerland. Inflammation is characterized by an excess of cell proliferation often leading to fibrosis and sclerosis with subsequent loss of organ function. We hypothesized that these features may be ameliorated by induction of cell cycle arrest and apoptosis as result of therapy with matrix metalloproteinase (MMP) inhibitors. In our study, mesangial cells and experimental mesangial proliferative glomerulonephritis provided the model of inflammation. First, we investigated the effect of the MMP inhibitor BB-1101 in anti-Thy1.1 nephritis. The numbers of apoptotic glomerular cells in nephritic rats increased about 4 and 6 times as a result of BB-1101 therapy, observed 11 and 14 days after induction of disease, respectively. Subsequently, rat mesangial cells were exposed to an MMP inhibitor in vitro. Fluorescence-activated cell sorter analyses of cells exposed to RO111-3456 demonstrated a dose-dependent cell cycle arrest in the G(0)/G(1) phase associated with increased expression of statin. The cell cycle arrest was followed by apoptosis as investigated by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) biotin nick-end labeling (TUNEL) and acridine orange/ethidium bromide stainings, as well as by annexin V binding. The induction of p53, p21, and bax, but not the Fas/FasL pathway appeared to play an important pathogenetic role. In summary, MMP inhibitors induce cell cycle arrest followed by apoptosis in mesangial cells. These features help to explain the anti-inflammatory effects of these compounds, such as reduction of mesangial cell proliferation and attenuation of extracellular matrix accumulation. In conclusion, induction of cell cycle arrest with subsequent apoptosis may offer new perspectives in the therapy of inflammation even beyond kidney diseases. PMID: 11259528 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 394: Proc Natl Acad Sci U S A. 2001 Mar 13;98(6):3381-6. Telomere dysfunction alters the chemotherapeutic profile of transformed cells. Lee KH, Rudolph KL, Ju YJ, Greenberg RA, Cannizzaro L, Chin L, Weiler SR, DePinho RA. Department of Adult Oncology, Dana-Farber Cancer Institute, Departments of Medicine and Genetics, and Dermatology, Harvard Medical School, Boston, MA 02115, USA. Telomerase inhibition has been touted as a novel cancer-selective therapeutic goal based on the observation of high telomerase levels in most cancers and the importance of telomere maintenance in long-term cellular growth and survival. Here, the impact of telomere dysfunction on chemotherapeutic responses was assessed in normal and neoplastic cells derived from telomerase RNA null (mTERC(-/-)) mice. Telomere dysfunction, rather than telomerase per se, was found to be the principal determinant governing chemosensitivity specifically to agents that induced double-stranded DNA breaks (DSB). Enhanced chemosensitivity in telomere dysfunctional cells was linked to therapy-induced fragmentation and multichromosomal fusions, whereas telomerase reconstitution restored genomic integrity and chemoresistance. Loss of p53 function muted the cytotoxic effects of DSB-inducing agents in cells with telomere dysfunction. Together, these results point to the combined use of DSB-inducing agents and telomere maintenance inhibition as an effective anticancer therapeutic approach particularly in cells with intact p53-dependent checkpoint responses. PMID: 11248087 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 395: Zhonghua Bing Li Xue Za Zhi. 1998 Apr;27(2):102-4. [The influence of Kupffer cells on experimental hepatocarcinogenesis] [Article in Chinese] Zhu H, Ruan Y, Wu Z. Department of Ultrastructural Pathology, Tongji Medical University, Wuhan 430030. OBJECTIVE: In order to explore the influence of Kupffer cells on experimental hepatocarcinogenesis. METHODS: A comparative study on the expression of proliferating cell nuclear antigen (PCNA), epidermal growth factor (EGF), ras P21, p53 protein and c-myc gene by means of immunohistochemistry or in situ hybridization during the diethylnitrosamine (DENA)-induced hepatocarcinogenesis performed in rats with and without pretreatment with gadolinium chloride (GC) which might effectively block the activity of Kupffer cells. RESULTS: There was no marked difference in the expression of PCNA and EGF in the liver tissue between the above two groups animals. The positive rate of ras P21 was markedly higher in the GC + DENA group than in the DENA group. The positive rate of p53 protein in GC + DENA group was slightly higher than that of the DENA group, however, the appearance of expression was markedly earlier in the former group (in the 11th and the 19th week respectively). The expression intensity of c-myc gene was markedly higher in GC + DENA group that in DENA group. CONCLUSIONS: The results suggest that Kupffer cells can reduce hepatotoxicity induced by chemical carcinogen, and Kupffer cells may play an inhibitory effect on the process of hepatocarcinogenesis. PMID: 11244957 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 396: Chin Med Sci J. 1997 Mar;12(1):6-10. Molecular alteration of alpha-induced transformed Syrian hamster embryo cells. Shou J, Zhang Y, Wu D. Institute of Radiation Medicine, Beijing 100850. Syrian hamster embryo (SHE) cells are irradiated by alpha particles emitted from Plutonium-238 in vitro. Transfection frequencies of donor DNA derived from passaged cells, including monocloned cells from 20th passage cells, after irradiation are parallel with their tumorigenicity of donor cells. After transformation, expressions of H-ras and c-myc genes are in the state of activation, which might be resulted from occurrence of mutation in H-ras gene and hypomethylation of c-myc gene respectively, even though no alteration was observed on their restriction fragment length polymorphisms (RELP) patterns of both genes. On the other hand, expression of p53 gene is also found to be in the state of activation in transformant, but no heavy staining of p53 protein appeared in the transformant-derived tumor with p53 specific McAb HD 200. This might be result from the partial deletion of p53 cDNA in transformant by reverse transcriptional polymerase chain reaction (RT-PCR). These results imply that activation of H-ras and c-myc genes coupled with inactivation of p53 tumor suppressor gene play important role in alpha particle-induced cell transformation. PMID: 11243103 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 397: Mol Cell Biol. 2001 Mar;21(6):2144-53. Dual inactivation of RB and p53 pathways in RAS-induced melanomas. Bardeesy N, Bastian BC, Hezel A, Pinkel D, DePinho RA, Chin L. Department of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA. The frequent loss of both INK4a and ARF in melanoma raises the question of which INK4a-ARF gene product functions to suppress melanoma genesis in vivo. Moreover, the high incidence of INK4a-ARF inactivation in transformed melanocytes, along with the lack of p53 mutation, implies a cell type-specific role for INK4a-ARF that may not be complemented by other lesions of the RB and p53 pathways. A mouse model of cutaneous melanoma has been generated previously through the combined effects of INK4a(Delta2/3) deficiency (null for INK4a and ARF) and melanocyte-specific expression of activated RAS (tyrosinase-driven H-RAS(V12G), Tyr-RAS). In this study, we made use of this Tyr-RAS allele to determine whether activated RAS can cooperate with p53 loss in melanoma genesis, whether such melanomas are biologically comparable to those arising in INK4a(Delta2/3-/-) mice, and whether tumor-associated mutations emerge in the p16(INK4a)-RB pathway in such melanomas. Here, we report that p53 inactivation can cooperate with activated RAS to promote the development of cutaneous melanomas that are clinically indistinguishable from those arisen on the INK4a(Delta2/3) null background. Genomewide analysis of RAS-induced p53 mutant melanomas by comparative genomic hybridization and candidate gene surveys revealed alterations of key components governing RB-regulated G(1)/S transition, including c-Myc, cyclin D1, cdc25a, and p21(CIP1). Consistent with the profile of c-Myc dysregulation, the reintroduction of p16(INK4a) profoundly reduced the growth of Tyr-RAS INK4a(Delta2/3-/-) tumor cells but had no effect on tumor cells derived from Tyr-RAS p53(-/-) melanomas. Together, these data validate a role for p53 inactivation in melanomagenesis and suggest that both the RB and p53 pathways function to suppress melanocyte transformation in vivo in the mouse. PMID: 11238948 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 398: J Virol. 2001 Apr;75(7):3474-9. Oncolytic activity of vesicular stomatitis virus is effective against tumors exhibiting aberrant p53, Ras, or myc function and involves the induction of apoptosis. Balachandran S, Porosnicu M, Barber GN. Department of Microbiology and Immunology and Sylvester Comprehensive Cancer Center, University of Miami School of Medicine, Miami, Florida 33136, USA. We have recently shown that vesicular stomatitis virus (VSV) exhibits potent oncolytic activity both in vitro and in vivo (S. Balachandran and G. N. Barber, IUBMB Life 50:135-138, 2000). In this study, we further demonstrated, in vivo, the efficacy of VSV antitumor action by showing that tumors that are defective in p53 function or transformed with myc or activated ras are also susceptible to viral cytolysis. The mechanism of viral oncolytic activity involved the induction of multiple caspase-dependent apoptotic pathways was effective in the absence of any significant cytotoxic T-lymphocyte response, and occurred despite normal PKR activity and eIF2alpha phosphorylation. In addition, VSV caused significant inhibition of tumor growth when administered intravenously in immunocompetent hosts. Our data indicate that VSV shows significant promise as an effective oncolytic agent against a wide variety of malignant diseases that harbor a diversity of genetic defects. PMID: 11238874 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 399: Biochem Biophys Res Commun. 2001 Mar 9;281(4):945-50. c-myc activation in early coronary lesions in experimental hypercholesterolemia. de Nigris F, Lerman LO, Rodriguez-Porcel M, De Montis MP, Lerman A, Napoli C. Department of Medicine, University of Naples, Naples, 80131, Italy. This study tested the hypothesis that c-Myc activation, an oxidation-sensitive transcription factor, and its binding partner Max occurs in coronary arteries of hypercholesterolemic (HC) pigs, and can be attenuated by chronic antioxidant intervention. Coronary arteries were isolated from normal, HC pigs, or HC supplemented with antioxidant vitamins (HC + vitamins). The expression of the c-Myc/Max complex, and its target genes GADD45 and p53, was studied in nonatherosclerotic, early lesions (LL), positively staining for oil-red-O, in adjacent lesion-prone regions (PL), and in healthy segments (HV). The expression of c-Myc and Max in HC was 2- to 3-fold greater in PL, and 4-fold in LL, compared to normal vessels (P < 0.01). The expression of GADD45 was down-regulated, and of p53 increased, in the same regions. These alterations were attenuated in the HC + vitamins. Thus, c-Myc activation is an early atherosclerosis, in both PL and LL coronary arterial regions, and can be blunted by chronic dietary antioxidant intervention. Copyright 2001 Academic Press. PMID: 11237752 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 400: Leukemia. 2001 Mar;15(3):362-70. The leukemogenic transcription factor E2a-Pbx1 induces expression of the putative N-myc and p53 target gene NDRG1 in Ba/F3 cells. Rutherford MN, Bayly GR, Matthews BP, Okuda T, Dinjens WM, Kondoh H, LeBrun DP. Department of Pathology, Queen's University, Kingston, Ontario, Canada. The chimeric transcription factor E2a-Pbx1 is expressed as a result of the 1;19 chromosomal translocation in some 5% of cases of pediatric acute lymphoblastic leukemia. We investigated the biological and transcriptional consequences of forced expression of E2a-Pbx1 in the interleukin-3 (IL-3) dependent, bone marrow-derived cell line Ba/F3. We show that forced expression of E2a-Pbx1 induces apoptosis in Ba/F3 cells without apparent effects on cell cycle progression. This pro-apoptotic effect is enhanced on cytokine deprivation. Furthermore, using cDNA representational difference analysis (RDA), we show that these cellular effects are associated with marked induction of the gene NDRG1, which was previously identified as a target of transcriptional repression by N-myc and induction by the tumor suppressor protein p53. We identify a portion of the NDRG1 promoter capable of mediating transcriptional induction by E2a-Pbx1 and show that NDRG1 is also induced on simple IL-3 deprivation of BaF3 cells. Although we show that E2a-Pbx1 induction of NDRG1 is not impaired as a result of targeting p53 using HPV E6, and therefore does not appear to be p53-dependent, our results overall are consistent with the notion that induction of NDRG1 by E2a-Pbx1 may represent part of an apoptotic or cytostatic cellular response to oncogene activation. PMID: 11237058 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 401: FEBS Lett. 2001 Feb 16;490(3):117-22. Pathways governing G1/S transition and their response to DNA damage. Bartek J, Lukas J. Department of Cell Cycle and Cancer, Institute of Cancer Biology, Danish Cancer Society, Strandboulevarden 49, DK-2100, Copenhagen, Denmark. bartek@biobase.dk The ability to self-replicate is a fundamental feature of life, reflected at the cellular level by a highly regulated process initiated in G1 phase via commitment to a round of DNA replication and cell division. Here we briefly highlight recent advances in understanding the molecular pathways which govern the decision of mammalian somatic cells to enter S phase, and the so-called cell cycle checkpoints which guard the G1/S transition and S phase progression against potentially deleterious effects of genotoxic stress. Particular emphasis is put on the emerging parallel yet cooperative pathways of retinoblastoma protein (pRB)-E2F and Myc, their convergence to control the activity of the cyclin-dependent kinase 2 (Cdk2) at the G1/S boundary, as well as the two waves of checkpoint responses at G1/S: the rapid pathway(s) leading to Cdc25A degradation, and the delayed p53-p21 cascade, both silencing the Cdk2 activity upon DNA damage. Publication Types: Review Review, Tutorial PMID: 11223026 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 402: Int J Radiat Biol. 2001 Jan;77(1):31-40. Oncoprotein expression in human breast epithelial cells transformed by high-LET radiation. Calaf G, Hei TK. Center for Radiological Research, College of Physicians and Surgeons of Columbia Unviersity, New York, NY 10032, USA. gmc24@columbia.edu PURPOSE: The aim of the present work was to analyze the expression of oncoproteins that are frequently altered in breast cancer with specific phenotypic stages in the neoplastic process. MATERIALS AND METHODS: Expression of c-myc, c-jun, c-Ha-ras and the tumor suppressor gene p53 oncoproteins were examined by immunohistochemical staining coupled with confocal microscopy in transformed and tumorigenic human breast epithelial cells induced by high-LET alpha-particles (150 kcV/microm). RESULTS: MCF-10F cells, irradiated with single and double doses of 60 cGy alpha-particles and subsequently treated with cstrogen, showed gradual phenotypic changes including altered morphology, increased cell proliferation relative to control, anchorage-independent growth, invasive capabilities and tumorigenicity in nude mice. MCF-10F cells irradiated with a second dose of 60 cGy alpha-particles after estrogen treatment (60 cGy+ E/60 cGy+E) showed tumorigenicity both in SCII) and nude mice. Alterations in the protein expression of several oncogenes including c-myc, c-jun, c-Ha-ras and the tumor suppressor gene p53 were detected in alpha-particle-irradiated cells and in those cells subsequently cultured in the presence of estrogen. The expression level of these oncoproteins correlated with the progressive nature of the neoplastic process. CONCLUSION: These studies suggest that overexpression of several oncoproteins is important in the neoplastic transformation of human breast epithelial cells induced by high-LET radiation. In addition, use of endocrine factors such as estrogen allows the examination of various aspects of protein expression providing the basis for understanding the complex interactions of hormones and genes. PMID: 11213348 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 403: Cell Mol Life Sci. 1999 Dec;56(11-12):908-17. Proteasomes in apoptosis: villains or guardians? Wojcik C. Department of Histology and Embryology, Institute of Biostructure, Medical University of Warsaw, Warszawa, Poland. cwojcik@ib.amwaw.edu.pl The proteasome (multicatalytic proteinase complex, prosome) is a major cytoplasmic proteolytic enzyme, responsible for degradation of the vast majority of intracellular proteins. Proteins degraded by the proteasome are usually tagged with multiple ubiquitin moieties, conjugated to the substrates by a complicated cascade of enzymes. Over the last years, evidence has accumulated that changes in the expression and activity of the different components of the ubiquitin-proteasome system occur during apoptosis. Proteasome inhibitors have been used to induce apoptosis in various cell types, whereas in others, these compounds were able to prevent apoptosis induced by different stimuli. The proteasome mediated step(s) in apoptosis is located upstream of mitochondrial changes and caspase activation, and can involve in different systems Bcl-2, Jun N-terminal kinase, heat shock proteins, Myc, p53, polyamines and other factors. Publication Types: Review Review, Tutorial PMID: 11212325 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 404: Eur J Cancer Prev. 2000 Dec;9(6):439-42. Comparison of early onco/suppressor gene expressions in peripheral leukocytes and potential target organs of rats exposed to the carcinogen 1-nitropyrene. Ember I, Kiss I, Gyongyi Z, Varga CS. Department of Preventive Medicine, Faculty of Medicine, University of Pecs, Hungary. ember@pubhealth.pote.hu An in-vivo model has been developed to study early expressions of c-myc, Ha-ras oncogenes and p53 suppressor gene as biomarkers of carcinogenic exposure and/or tumorigenesis. In order to validate the in-vivo expression changes as biomarkers, rats were treated with the outdoor air pollutant carcinogen 1-nitropyrene. The gene expression levels were measured after 24 and 48 h in potential target tissues (lung, liver, lymph nodes, kidneys, spleen) and in peripheral blood leukocytes. Another main objective was to prove the applicability of leukocytes as a surrogate tissue, having a similar expression pattern of the selected genes upon carcinogenic exposure. The c-myc oncogene was not suitable as an early biomarker because of the lack or low level of its expression. However, in the case of the other oncogene Ha-ras and the suppressor gene p53, remarkable and early changes were detected in the expression signals. Similar expression patterns could only be detected in leukocytes and the spleen; therefore we continue this validation study by using other types and routes of exposure. PMID: 11201684 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 405: Nippon Rinsho. 2001 Jan;59(1):110-8. [Gene therapy for breast cancer] [Article in Japanese] Takeda Y, Eriguchi M. Department of Surgery, Institute of Medical Science, University of Tokyo. Not only the local treatments like surgery and radiation but also the systemic treatments like chemotherapy and hormone therapy are rather effective on both primary and metastatic breast cancer patients. Nevertheless, the curativity and survival of this disease have been not satisfied yet. The difficulties of the treatment seems the emergence of drug-resistant cells and the low immunity of the host. Gene therapy offers a potentially useful approach for the treatment of breast cancer. The approaches of gene therapy for breast cancer that are now undergoing as clinical protocols in USA can be divided into three strategies: (1) approaches that alter the metabolic or signaling pathways within the breast cancer cell; (2) approaches designed to enhance the immune response to the tumor cells(immuno gene therapy); and (3) approaches that use the drug-resistant gene with chemotherapy. According to the new biology of breast cancer by Fisher, the systemic treatments are more important. Immuno-therapy seems especially promising in this field. Moreover, the immuno gene therapy is hopeful that could overcome the difficulties like heterogeneity and low immunogenicity of breast cancer cell. Publication Types: Review Review, Tutorial PMID: 11197840 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 406: Bull Cancer. 2000 Sep;87(9):621. [Telomerase: prudence! prudence!] [Article in French] Larsen CJ. Publication Types: News PMID: 11184448 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 407: Histopathology. 2001 Feb;38(2):111-9. Interrelationship between Epstein-Barr virus infection in gastric carcinomas and the expression of apoptosis-associated proteins. Ishii H, Gobe G, Kawakubo Y, Sato Y, Ebihara Y. Second Department of Pathology, Tokyo Medical University, Japan. hhishii@tokyo-med.ac.jp AIMS: Epstein-Barr virus (EBV) and its associated proteins may be protective against the occurrence of apoptosis that would normally inhibit cancer development and progression. Alternatively, the viral infection may cause altered or mutated expression of oncogenes or tumour suppressor genes that are necessary for tumour development, an action that may also involve apoptosis. In this study, a relationship was sought between occurrence of EBV infection, expression of apoptosis-associated proteins (tumour suppressor gene p53 and oncogenes c-myc and bcl-2) and levels of cell death (apoptosis or necrosis) in 119 cases of gastric carcinoma. METHODS AND RESULTS: The EBV status of the gastric carcinomas (using the EBV-encoded small RNA I (EBER-1) and in-situ hybridization), stage and grade of tumour and sex of patients were compared for bcl-2, p53 and c-myc expression patterns. EBER-1 was detected in approximately 20% of cases studied. There was no significant correlation between levels of cell death in the tumour tissue and EBV status. In the protein analyses, development and progression of gastric carcinoma, with or without EBV infection, was independent of bcl-2 expression. However, in gastric cancers with EBV infection, p53 overexpression was inhibited and c-myc expression was increased in early stage cancers, in comparison with decreased c-myc expression in late stage cancers. CONCLUSIONS: The p53 and c-myc expression patterns indicate that EBV-infected gastric carcinomas are less likely to have a natural regression via apoptosis at an early stage and explain, in part, the resistance to treatment of late stage of gastric cancers. PMID: 11207824 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 408: Int J Oncol. 2001 Mar;18(3):449-59. The human oncoprotein MDM2 uses distinct strategies to inhibit transcriptional activation mediated by the wild-type p53 and its tumor-derived mutants. Brown DR, Deb D, Frum R, Hickes L, Munoz R, Deb S, Deb SP. Department of Biochemistry and Molecular Biophysics and the Massey Cancer Center, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA. Human MDM2 (hMDM2) inhibits transcriptional activation mediated by wild-type p53 and its tumor-derived mutants. We present evidence to show that hMDM2 interacts with the tumor-derived mutants of p53 and inhibits transcriptional activation of the human c-myc promoter mediated by the tumor-derived mutants of p53 through two domains. These two domains of hMDM2 are able to function independent of each other. Interaction with either of the domains is sufficient for inhibition of mutant p53-mediated transactivation. One of these domains is the same as the wild-type p53 interaction domain of hMDM2, whereas a second domain is situated within amino acid 190 and 276 residues and is specific for mutant p53. hMDM2 does not inhibit transcriptional activation mediated by the transcriptional activator VP16, suggesting that the inhibition is not mediated by inactivation of a general transcription factor. The transactivation and the oligomerization domains of mutant p53 are dispensable for its interaction with hMDM2. Thus, both hMDM2 and p53 recognize each other through unique domains. These observations suggest that forms of hMDM2 incapable of interacting with the wild-type p53, and are often expressed in transformed cells, would inhibit mutant p53-mediated transactivation and antagonize the tumorigenic function of mutant p53. This inhibitory function of hMDM2 may account for infrequent co-occurrence of p53 mutation and hMDM2 overexpression in cancer cells. Our results also suggest distinct mechanisms for wild-type and mutant p53-mediated transcriptional activation. PMID: 11179471 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 409: Cancer Lett. 2001 Jan;162 Suppl:S5-S10. Molecular and cytogenetic alterations in early stage of carcinogenesis of human lung. Cheng S, Gao Y, Dong X, Lu Y, An Q, Tong T, Wang Y. Department of Chemical Etiology and Carcinogenesis, Cancer Institute (Hospital), Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China. chengsj@pubem.cicams.ac.cn In an attempt to reveal the genetic and epigenetic abnormalities in early stage of carcinogenesis of human lung cancer, a human bronchial epithelial cell line was immortalized by transfection with the Simian virus early region genes (SV40T); the biological features of the stable transfected cells were compared to human non-small cell lung cancer (NSCLC) specimens. The immortalized bronchial epithelial cells did not develop tumors but premalignant lesions in animal models. However, several genetic changes, including chromosome deletion and aneuploidy, altered expression of oncogenes and tumor suppressor genes occur not only in invasive NSCLC (human specimens) but also in the early stage of lung carcinogenesis (premalignant lesions) in this transfection model. PMID: 11164184 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 410: Biochem Biophys Res Commun. 2000 Apr 13;270(2):406-14. Induction of apoptosis and mitosis inhibition by degraded DNA lipotransfection mimicking genotoxic drug effects. Schiavone N, Papucci L, Luciani P, Lapucci A, Donnini M, Capaccioli S. Department of Experimental Pathology and Oncology, University of Florence, Viale G.B. Morgagni 50, Florence, 50134, Italy. Genotoxic damage induces cell cycle arrest and/or apoptosis by activation of p53 oncosuppressor protein. A number of anticancer drugs are genotoxic and their damaging effect upon cells is mediated by this mechanism. Microinjection of defined DNA species directly into nucleus has been reported previously to activate p53 and inhibit cell cycle. Here, we demonstrate that simple addition of heterogeneous degraded DNA to cultured cells (Rat-1 fibroblasts) in combination with lipotransfecting agent DOTAP leads to apoptosis induction and mitosis inhibition by a molecular mechanism which mimics that of the cellular response to genotoxic anticancer agents. Indeed, both cellular effects induced by lipotransfected degraded DNA (essentially, heterogeneous small DNA fragments) are associated to p53 activation and modulated by two apoptosis-related genes, such as bcl-2 and c-myc, which also modulate the apoptotic threshold to anticancer agents. Here we raise the hypothesis of exogenous DNA segment lipotransfection as possible new tool for anticancer therapy. Copyright 2000 Academic Press. PMID: 10753638 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 411: Cancer Res. 2000 Dec 15;60(24):6868-74. Gene expression profiling of low-grade diffuse astrocytomas by cDNA arrays. Huang H, Colella S, Kurrer M, Yonekawa Y, Kleihues P, Ohgaki H. Unit of Molecular Pathology, International Agency for Research on Cancer (IARC), Lyon, France. Diffuse astrocytoma WHO grade II is a well-differentiated, slowly growing tumor that has an inherent tendency to progress to anaplastic astrocytoma (WHO grade III) and, eventually, to glioblastoma (WHO grade IV). Little is known about its molecular basis, except for p53 mutations that are found in >60% of cases. In a search for additional genetic alterations, we carried out gene expression profiling of 11 diffuse astrocytomas using cDNA expression arrays. Expression of six genes (TIMP3, c-myc, EGFR, DR-nm23, nm23-H4, and GDNPF) was detected in 64-100% of diffuse astrocytomas, but not in nontumorous brain tissue. Seven genes (AAD14, SPARC, LRP, PDGFR-alpha, 60S ribosomal protein L5, PTN, and hBAP) were found to be up-regulated more than 2-fold in 20-60% of cases, whereas 11 genes (IFI 9-27, protein kinase CLK, TDGF1, BIN1, GAB1, TYRO3, LDH-A, adducin 3, GUK1, CDC10, and KRT8) were down-regulated to less than 50% of normal levels in 64-100% of cases. Semiquantitative conventional reverse transcription-PCR was performed for 11 genes, 9 of which showed an expression profile similar to that obtained with cDNA expression arrays. Immunohistochemical staining for SPARC showed cytoplasmic immunoreactivity of neoplastic cells in all diffuse astrocytomas analyzed. These results indicate significant changes in gene expression in diffuse astrocytomas, but it remains to be shown which of these are causally related to the transformation of glial cells. PMID: 11156382 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 412: Toxicology. 2000 Nov 30;155(1-3):83-90. Chemopreventive effects of grape seed proanthocyanidin extract on Chang liver cells. Joshi SS, Kuszynski CA, Bagchi M, Bagchi D. Department of Cell Biology, University of Nebraska Medical Center, Omaha 68198-6395, USA. ssjoshi@unmc.edu In an attempt to ameliorate the chemotherapy associated normal cell toxicity, in this study a known antioxidant, grape seed proanthocyanidin extract (GSPE) using Chang liver cells has been used. Chang liver cells were treated in vitro with idarubicin (Ida) (30 nM) and 4-hydroxyperoxycyclophosphamide (4-HC) (1 microg/ml) with or without proanthocyanidin (25 microg/ml). The cells were grown in vitro and the growth rate of the cells were determined using MTT assay. The results showed that the GSPE decreased growth inhibitory effects of Ida and 4-HC on Chang liver cells in vitro. Since these chemotherapeutic agents are known to induce apoptosis in the target cells, these cells were also analyzed for presence of apoptotic cells using flow cytometry. The GSPE decreased the number of apoptotic cell population induced by either chemotherapy. In an attempt to determine the mechanisms of ameliorating effects of proanthocyanidin, the expression of apoptosis/cell cycle/growth related genes, Bcl-2, p53 and c-myc was determined in the treated and control cells using Western blotting or reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. There was an increased expression of Bcl-2 in the cells treated with GSPE. However, there was a significant decrease in the expression of other cell cycle related genes such as p53 and c-myc in these cells following treatment with GSPE. Thus, these results indicate that proanthocyanidin can be a potential candidate to ameliorate the toxic effects associated with chemotherapeutic agents used in treatment of cancer. PMID: 11154800 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 413: Horm Res. 2000;53(5):251-5. Antiproliferative effect and cell cycle modulation by melatonin on GH(3) cells. Fornas O, Mato ME, Webb SM. Experimental Endocrinology Laboratory, Department of Endocrinology, Research Institute, Hospital de Sant Pau, Autonomous University of Barcelona, Spain. We have investigated the effect of melatonin on cell proliferation and modulation, in the GH(3) experimental rat pituitary cell line; the expression of oncogenes c-myc, c-jun and the tumor suppressor gene p53 were also analyzed basally and after exposure to melatonin (10(-6), 10(-8) and 10(-10) M). Melatonin exhibited an antiproliferative effect at all the doses tested, decreasing the proliferating index by 50%. After exposure to melatonin, a decrease in Ki67 and Proliferation cell nuclear antigen occurred acute- and transiently (at 2 h) after a single dose which recovered at 4 h, as well as chronically after repeated 12-hour doses which persisted at 48 h; a similar behavior was observed both acute- and chronically for c-myc and c-jun, while it was opposite for p53, rising acute- and transiently as well as after repeated exposure. These results demonstrate that melatonin modulates the proliferation mechanisms of the GH(3) cells. Copyright 2000 S. Karger AG, Basel PMID: 11150887 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 414: Nat Cell Biol. 2001 Jan;3(1):1-7. DAP kinase activates a p19ARF/p53-mediated apoptotic checkpoint to suppress oncogenic transformation. Raveh T, Droguett G, Horwitz MS, DePinho RA, Kimchi A. Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel. DAP kinase is a pro-apoptotic calcium-regulated serine/threonine kinase, whose expression is frequently lost in human tumours. Here we show that DAP kinase counteracts oncogene-induced transformation by activating a p19ARF/p53-dependent apoptotic checkpoint. Ectopic expression of DAP kinase suppressed oncogenic transformation of primary embryonic fibroblasts by activating p53 in a p19ARF-dependent manner. Consequently, the fibroblasts underwent apoptosis, characterized by caspase activation and DNA fragmentation. In response to c-Myc or E2F-1, the endogenous DAP kinase protein was upregulated. Furthermore, functional or genetic inactivation of the endogenous DAP kinase reduced the extent of induction of p19ARF/p53 and weakened the subsequent apoptotic responses to c-Myc or E2F-1. These results establish a role for DAP kinase in an early apoptotic checkpoint designed to eliminate pre-malignant cells during cancer development. PMID: 11146619 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 415: Int J Cancer. 2001 Jan 15;91(2):173-9. Erratum in: Int J Cancer 2001 Sep 15;93(6):916. Chun-Yu Wong B [corrected to Wong BC]. Arsenic trioxide induces apoptosis in human gastric cancer cells through up-regulation of p53 and activation of caspase-3. Jiang XH, Wong BC, Yuen ST, Jiang SH, Cho CH, Lai KC, Lin MC, Kung HF, Lam SK. Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong. Arsenic trioxide (As(2)O(3)) can induce clinical remission in patients suffering from acute promyelocytic leukemia, through induction of apoptosis and activation of caspases. We investigated the potential use of As(2)O(3) in human gastric cancer and its possible mechanisms. Human gastric cancer cell lines AGS and MKN-28 were treated with various concentrations (0.1 to 100 microM) of As(2)O(3) for 24 to 72 hr. Apoptosis was determined by acridine orange staining, flow cytometry and DNA fragmentation. Protein levels of p53, p21(waf1/cip1), c-myc, bcl-2 and bax were detected by Western blotting. Effects of As(2)O(3) on caspase-3 protease activity, its protein concentration and cleavage of poly(ADP)-ribose polymerase (PARP) were also studied. As(2)O(3) inhibited cell growth and induced apoptosis in both cell lines, though AGS cells were more sensitive. As(2)O(3) induced apoptosis in AGS cells in a concentration- and time-dependent manner. Treatment resulted in a marked increase in p53 protein levels as early as 4 hr. Co-incubation with p53 anti-sense oligo-nucleotide suppressed As(2)O(3)-induced intracellular p53 over-expression and apoptosis. As(2)O(3) increased the activity of caspase-3, with appearance of its 17 kDa peptide fragment, and cleavage of PARP, with appearance of the 85 kDa cleavage product, both in parallel with the induction of apoptosis. Both the tripeptide caspase inhibitor zVAD-fmk and the specific caspase-3 inhibitor DEVD-fmk partially suppressed As(2)O(3)-induced caspase-3 activation and apoptosis. As(2)O(3) inhibits cell growth and induces apoptosis in gastric cancer cells, involving p53 over-expression and activation of caspase-3. The potential use of this compound in the treatment of gastric cancer is worth further investigation. Copyright 2001 Wiley-Liss, Inc. PMID: 11146441 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 416: Anticancer Drugs. 2000 Oct;11(9):747-56. Differential regulation of P53, c-Myc, Bcl-2, Bax and AFP protein expression, and caspase activity during 10-hydroxycamptothecin-induced apoptosis in Hep G2 cells. Zhang XW, Xu B. Divison of Cancer Pharmacology, Shanghai Institue of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Science. 10-Hydroxycamptothecin (HCPT), a DNA topoisomerase I (Topo I) inhibitor, exhibited a remarkable apoptosis-inducing effect on human hepatoma Hep G2 cells. We studied the effect of HCPT upon the expression of P53, c-Myc, Bcl-2, Bax and alpha-fetoprotein (AFP) proteins, and caspase (caspase-1 and caspase-3) activity of Hep G2 cells. It showed that HCPT at a dose of 0.1 microg/ml increased the expression of P53, c-Myc and Bax protein, and decreased the expression of Bcl-2 and AFP. The increase of P53, which was remarkable after only 3 h incubation with HCPT, occurred much earlier than the changes of other proteins, suggesting that the increase of P53 expression may be the upstream event in the apoptosis of Hep G2 cells induced by HCPT. Both caspase-1 and caspase-3 were activated in Hep G2 cells by HCPT treatment, suggesting that caspase-1 and caspase-3 are involved in the process of apoptosis in Hep G2 cells, and may be the main effectors of the apoptosis. PMID: 11129738 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 417: Cancer Gene Ther. 2000 Nov;7(11):1491-503. Induced p21WAF1 expression acts to reverse myc myelomonocytic cell transformation. Dolnikov A, Millington M, Sun LQ, Symonds G. Department of Clinical Pharmacology and Toxicology, St. Vincents Hospital, Darlinghurst, NSW, Australia. Two murine myelomonocytic cells lines were used to examine p21WAF1 expression in myc-induced cell transformation. tEMmyc4 and FDLV are two v-myc-transformed immortalised myeloid cell lines exhibiting different transformed phenotypes. FDLV cells were derived from the transduction of v-myc into FDC-P1 cells and retain growth factor (IL-3) dependence, whereas tEMmyc4 cells were derived from the transduction of embryonal monocytes with v-myc and are growth factor-independent, constitutively express endogenous CSF-1, and are highly tumorigenic in syngeneic mice. Both cell lines were found to exhibit low p21WAF1 expression. When examined in tEMmyc4 cells, neither the p53-dependent pathway (mitomycin C or exogenous p53) nor p53-independent pathway (TPA or growth factor, CSF-1, stimulation) acted to increase p21WAF1 levels. Growth factor (IL-3) withdrawal, shown to reduce p21WAF1 levels in parental FDC-P1 cells, failed to do this in FDLV cells. The dependence of p21WAF1 expression on v-myc was further demonstrated by showing that a v-myc-targeted ribozyme, which acts to decrease v-myc RNA, increased p21WAF1 levels in tEMmyc4 cells. Enforced expression of exogenous p21WAF1 in tEMmyc4 cells with dysfunctional growth cycle (including growth arrest and increased susceptibility to apoptosis) was examined. p21WAF1 partially restored cell cycle regulation and apoptosis as well as inhibited the delayed cell cycle progression and apoptosis induced by mitomycin C or serum withdrawal. These results show p21WAF1 expression to be affected by v-myc and a restoration of p21WAF1 expression to partially reverse myc-mediated transformation. PMID: 11129291 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 418: Oncogene. 2000 Nov 30;19(51):5906-18. v-Jun sensitizes cells to apoptosis by a mechanism involving mitochondrial cytochrome C release. MacLaren A, Clark W, Gillespie DA. Beatson Institute for Cancer Research, Cancer Research Campaign Beatson Laboratories, Glasgow, Scotland, UK. v-Jun shares the ability of the Myc, E1A, and E2F oncogenes to both sustain cell cycle progression and promote apoptosis in the absence of mitogenic stimulation. To gain an insight into the mechanism of apoptosis sensitization, we examined the possible involvement of key regulatory proteins previously implicated in oncogene-induced cell death during v-Jun-induced apoptosis triggered by serum withdrawal. We observed that ectopic expression of the anti-apoptotic Bcl-2 protein, or of two downstream effectors of growth factor signalling, v-PI 3-Kinase and v-Src, partially or completely suppressed apoptosis. Apoptosis was also observed in the presence of serum growth factors when endogenous PI3K activity was blocked using the synthetic inhibitor LY294002, further suggesting an important role for PI3-K in cell survival. Cytochrome C was released into the cytosol of apoptotic v-Jun expressing cells, and this release was inhibited by Bcl-2, suggesting an important role for mitochondrial dysfunction in v-Jun induced apoptosis. In contrast, inhibition of Fas signalling using dominant negative FADD did not inhibit apoptosis, nor was there any evidence for accumulation or activation of p53 in v-Jun transformed cells. Consistent with this latter observation, inhibition of p53 function by HPV16 E6 protein had no effect on v-Jun induced cell death. Taken together, these results suggest that mitochondrial dysfunction is an important component of the mechanism through which v-Jun sensitizes cells to apoptosis, but that the apoptotic signals elicited by v-Jun upstream of the mitochondria do not depend on increased levels of p53 activity or Fas signalling. PMID: 11127822 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 419: Cancer Res. 2000 Dec 1;60(23):6623-9. Allelic deletions of cell growth regulators during progression of bladder cancer. Primdahl H, von der Maase H, Christensen M, Wolf H, Orntoft TF. Department of Clinical Biochemistry, Aarhus University Hospital, Denmark. Cell growth regulators include proteins of the p53 pathway encoded by the genes CDKN2A (p16, p14arf), MDM2, TP53, and CDKN1A (p21) as well as proteins encoded by genes like RB1, E2F, and MYCL. In the present study we investigated allelic deletions of all these genes in each recurrent bladder tumor from well-defined clinical material with more than 3 years of follow-up. We followed three groups (22 or 23 patients/group) of patients with: (a) recurrent noninvasive tumors (Ta); (b) primary muscle-invasive tumors (T2-T4); and (c) progressing tumors (Ta/T1 --> T2/T4). We found a significant difference in the numbers of gene loci hit by deletions muscle-invasive versus noninvasive tumors (P = 0.0000002), with the genes most often hit by deletions in muscle-invasive tumors being TP53, RB1, and MYCL. A number of novel findings were made. Losses of MYCL and RB1 alleles were more pronounced in patients having concomitant field disease because 11 of 14 informative cases showed losses compared with 3 of 8 cases without field disease. A more pronounced deletion of TP53 (P = 0.002) and RB1 (P = 0.02) was found in the progressing tumor group compared with the recurrent noninvasive group, and, finally, the combined loss of TP53 and RB1 was present only in the progressing tumor or muscle-invasive groups. Deletion of two or more loci in TP53, MYCL, RB1, and CDKN2A was found in 10 patients in the progressing tumor group and in only 1 patient in the recurrent noninvasive group (P = 0.004). The data demonstrate that a characteristic difference between recurrent noninvasive and recurrent progressing bladder tumors is loss of cell cycle-regulatory genes in the latter group. PMID: 11118045 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 420: Oncol Rep. 2001 Jan-Feb;8(1):131-6. Osteosarcoma in blood relatives. Longhi A, Benassi MS, Molendini L, Macchiagodena M, Picci P, Bacci G. Service of Chemotherapy, Istituti Ortopedici Rizzoli, 40136 Bologna, Italy. alessandra.longhi@ior.it Osteosarcoma is an uncommon tumor. Family occurrence of osteosarcoma is even rarer. Four cases of osteosarcoma in two siblings and in a father and son treated at our Institute with surgery and chemotherapy are reported. These patients had no other tumors in their family history, and had negative p53 mutations in exons 5-9 by SSCP analysis. RB, CDK4, MDM2, c-myc, c-fos, and p53 gene expression, which are the major genes involved in osteosarcoma susceptibility, were studied. Our results revealed an inactive form of p53 sporadically seen in the samples, a total loss of Rb protein expression, an increased expression of Cdk4, MDM2, c-fos, and c-myc proteins which literature currently reports being the principal alterations found in osteosarcoma. These findings confirm that specific genetic alterations occur in osteosarcoma pathogenesis. Publication Types: Case Reports Review Review of Reported Cases PMID: 11115584 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 421: Br J Cancer. 2000 Dec;83(12):1664-73. Erratum in: Br J Cancer 2001 Mar 23;84(6):874. Prognostic value of genomic alterations in minimal residual cancer cells purified from the blood of breast cancer patients. Austrup F, Uciechowski P, Eder C, Bockmann B, Suchy B, Driesel G, Jackel S, Kusiak I, Grill HJ, Giesing M. Institut fur Molekulare NanoTechnologie, Berghauser Str. 295, Recklinghausen, 45659, Germany. The prognostic value of disseminated tumour cells derived from 353 breast cancer patients was evaluated. Disseminated tumour cells were purified from blood using a newly established method and nucleic acids were subsequently isolated. We investigated genomic imbalances (GI) such as mutation, amplification and loss of heterozygosity of 13 tumour suppressor genes and 2 proto-oncogenes using DNA from isolated minimal residual cancer cells. Significant correlations were found between genomic alterations of the DCC - and c-erbB-2 genes in disseminated breast cancer cells and actuarial relapse-free survival. Furthermore, increasing numbers of genomic imbalances measured in disseminated tumour cells were significantly associated with worse prognosis of recurrent disease. Logistic regression and Cox multivariate analysis led to the identification of genomic imbalances as an independent prognostic factor. Determination of disseminated tumour cells by genotyping of oncogenes and tumour suppressor genes seems not only to be a useful adjunct in follow up of carcinoma patients but provides also valuable additional individualized prognostic and predictive information in breast cancer patients beyond the TNM system. Copyright 2000 Cancer Research Campaign. PMID: 11104564 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 422: Cancer Res. 2000 Nov 15;60(22):6276-80. Activation of the transcription factor Oct-1 in response to DNA damage. Zhao H, Jin S, Fan F, Fan W, Tong T, Zhan Q. Department of Radiation Oncology, Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA. Mammalian cells exhibit complex cellular responses to genotoxic stress, including cell cycle checkpoint, DNA repair, and apoptosis. Inactivation of these important biological events will result in genomic instability and cell transformation. It has been demonstrated that gene activation is a critical initial step during the cellular response to DNA damage. A number of investigations have shown that transcription factors are involved in the regulation of stress-inducible genes. These transcription factors include p53, c-Myc, and AP-1 (c-fos and c-jun). However, the role for the octamer-binding transcription factor Oct-1 in the DNA damage-activated response is unknown. In this report, we have presented the novel observation that the transcription factor Oct-1 is induced after cells are exposed to multiple DNA-damaging agents and therapeutic agents, including UV radiation, methylmethane sulfonate, ionizing radiation, etoposide, cisplatin, and camptothecin. The induction of the Oct-1 protein is mediated through a posttranscriptional mechanism and does not require the normal cellular function of the tumor suppressor p53, indicating that the Oct-1 protein, as a transcription factor, may play a role in p53-independent gene activation. In addition to increased protein level, the activity of Oct-1 DNA binding to its specific consensus sequence is also enhanced by DNA damage. Therefore, these results have implicated that the transcription factor Oct-1 might participate in cellular response to DNA damage, particularly in p53-independent gene activation. PMID: 11103783 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 423: FASEB J. 2001 Jan;15(1):31-33. Epub 2000 Nov 14. A retro-inverso peptide homologous to helix 1 of c-Myc is a potent and specific inhibitor of proliferation in different cellular systems. Pescarolo MP, Bagnasco L, Malacarne D, Melchiori A, Valente P, Millo E, Bruno S, Basso S, Parodi S. Laboratory of Experimental Oncology, National Institute for Cancer Research, 16132 Genoa, Italy. In 1998 we reported that an L-peptide derived from H1 of c-Myc (Int-H1-S6A,F8A), linked to an internalization sequence from the third a-helix of Antennapedia, was endowed with an antiproliferative and proapoptotic activity toward a human mammary cancer cell line: The activity apparently depends upon the presence of the Myc motif. In the present work we have added new dimensions to our original findings. It is known that short retro-inverso (RI-) peptides can assume a 3D conformation very close to their corresponding L-forms and can be recognized by the same monoclonal antibody. We synthesized a RI-peptide form of our original L-peptide: It was much more resistant to serum peptidases than the original molecule (a half life of days rather than hours); in addition, the RI-form of the original Antennapedia internalization sequence was perfectly capable of carrying a D-peptide into human cells. We have studied three different potentially active peptides. L-peptides: Int-H1wt, Int-H1-S6A,F8A. D-peptides: RI-Int -H1-S6A,F8A. We have also studied three presumed control peptides: Int and RI-Int (no H1 motif), H1-S6A,F8A (no internalization sequence). Both 'active' and 'control' peptides have essentially confirmed our expectations, however, in cells treated with the higher concentration (10 mM) of the control peptide RI-Int, non-Myc related side effects could be detected. In order to investigate whether the antiproliferative activities displayed by some of our molecules were indeed related to an interference with the role of c-Myc (and molecules of the family), we chose an iso-amphipathic modified peptide of the H1 motif, with a proximity coefficient >50% and where the major change was at position 7 (F-->A). From a family of 73 H1 motifs belonging to (H1-Loop-H2) hu man sequences, the smallest evolutionary distance from our reference peptide was observed for the H1 of N-Myc, L-Myc, c-Myc, H1-S6A,F8A of c-Myc, and Max, in that order. Our reference peptide was therefore appropriate as a check of whether we were indeed observing activities related to Myc functions. Both Int-H1isoamph and the corresponding RI-Int-H1isoamph peptide were synthesized and studied. In terms of biological targets, we added to the human mammary cancer line of our previous work (MCF-7 cells) a colon cancer line (HCT-116 cells) and also a system of normal cells: human peripheral blood lymphocytes (PBLs) stimulated with phytohemoagglutinin (PHA). Peptides carrying an iso-amphipathic-modified H1 sequence were always very clearly (3-10 times) less active than the corresponding peptides carrying a conserved "H1 of Myc" motif. This finding was noted in five independent situations (all the cellular models considered at the present time): MCF-7 cells treated with L-peptides; MCF-7 cells treated with RI-peptides; HCT-116 cells treated with L-peptides; PBLs treated with L-peptides; PBLs treated with RI-peptides. Modulation of transcription levels of ornithine decarboxylase (ODC), p53, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in PBLs treated with our different molecules, was well compatible with an interference by our active peptides at the level of Myc transcriptional activity. We had already reported a similar observation in MCF-7 cells. On a molar basis, RI-peptides were about 5-10 times more potent and 30-35 times more stable in complete culture medium, than their corresponding L-forms. RI-Int can probably internalize longer peptido-mimetic molecules (for instance molecules mimetic of (H1-Loop-H2), or even more. These possibilities open the way to rodent studies and to more potent/selective Myc inhibitors-two steps closer to a potential drug. PMID: 11099487 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 424: Mol Cell Biol. 2000 Dec;20(24):9271-80. v-Src generates a p53-independent apoptotic signal. Webb BL, Jimenez E, Martin GS. Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA. Evasion of apoptosis appears to be a necessary event in tumor progression. Some oncogenes, such as c-myc and E1A, induce apoptosis in the absence of survival factors. However, others, such as bcl-2 and v-src, activate antiapoptotic pathways. For v-Src, these antiapoptotic pathways are dependent on the function of Ras, phosphatidylinositol (PI) 3-kinase, and Stat3. Here we asked whether v-Src can activate a proapoptotic signal when survival signaling is inhibited. We show that when the functions of Ras and PI 3-kinase are inhibited, v-src-transformed Rat-2 fibroblasts undergo apoptosis, evidenced by loss of adherence, nuclear fragmentation, and chromosomal DNA degradation. The apoptotic response is dependent on activation of caspase 3. Under similar conditions nontransformed Rat-2 cells undergo considerably lower levels of apoptosis. Apoptosis induced by v-Src is accompanied by a loss of mitochondrial membrane potential and release of cytochrome c and is blocked by overexpression of bcl-2, indicating that it is mediated by the mitochondrial pathway. However apoptosis induced by v-Src is not accompanied by an increase in the level of p53 and is not dependent on p53 function. Thus v-Src generates a p53-independent proapoptotic signal. PMID: 11094078 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 425: Br J Pharmacol. 2000 Dec;131(7):1285-93. Effect of saikosaponin, a triterpene saponin, on apoptosis in lymphocytes: association with c-myc, p53, and bcl-2 mRNA. Hsu MJ, Cheng JS, Huang HC. Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan. 1. The mechanisms involved in the apoptotic effect of saikosaponin-d, a triterpene saponin from Bupleurum falcatum L., were studied in human CEM lymphocytes and compared with those of dexamethasone (3 x 10(-7) M). 2. Saikosaponin-d (10(-8) to 10(-5) M) inhibited the serum-stimulated [(3)H]-thymidine incorporation in a concentration-dependent manner. Dexamethasone also inhibited serum-stimulated [(3)H]-thymidine incorporation. 3. Cell viability was unaffected by saikosaponin-d until 10(-5) - 10(-4) M. Dexamethasone significantly reduced the number of viable cells. 4. Following saikosaponin-d (10(-5) - 10(-4) M) treatment, flow cytometry analysis of propidium iodide-stained cells showed a significant increase in the percentage of cells in the apoptotic region. Dexamethasone also significantly increased the percentage of apoptotic cells. The supravital exposure to propidium iodide and annexin V labelling demonstrated that saikosaponin-d (10(-5) - 10(-4) M) induced apoptosis as well as necrosis. 5. The apoptotic effect of saikosaponin-d (3 x 10(-6) - 10(-4) M) was also demonstrated by TUNEL analysis and DNA laddering. The percentage of apoptotic cells induced by saikosaponin-d (3 x 10(-6) - 10(-5) M) was unaffected by the presence of Z-VAD-FMK, indicating that saikosaponin-d-induced apoptosis may not be mediated by caspase activity. However, the percentage of apoptotic cells induced by dexamethasone was significantly reduced by the presence of Z-VAD-FMK. 6. Levels of c-myc, p53, and bcl-2 mRNA were analysed by the reverse transcription-polymerase chain reaction. Levels of c-myc and p53 mRNA were significantly increased, while the level of bcl-2 mRNA was decreased, by saikosaponin-d (10(-5) M) treatment. Dexamethasone did not significantly change the expression of these genes. 7. It is suggested that the apoptotic effect of saikosaponin-d may be partly mediated by increases in c-myc and p53 mRNA levels accompanied by a decrease in bcl-2 mRNA level. PMID: 11090099 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 426: Biotechniques. 2000 Nov;29(5):1100-6. Generation of monospecific peptide antibodies to the DNA binding domain of p53. Huppi K, Henderson D, Siwarski D, Hochman J, Bergel M, Tuchscherer G. Laboratory of Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. huppi@helix.nih.gov The DNA binding domain (DBD) is the most mutated region of p53 in tumors and has proven to be relatively resistant to the generation of specific antibodies. Template assembled synthetic peptide (TASP) synthesis of a peptide derived from the DBD creates a highly immunogenic molecule without the need for large carriers such as keyhole limpet hemocyanin (KLH). In addition, a rapid means of generating monoclonal antibodies can be achieved through immunization in conjunction with ABL/MYC retrovirus injection into recipient mice. In this paper, we demonstrate that an antibody generated by this means, KH2, reacts specifically with the DBD of p53. To date, this is the first example of a peptide immunogen used successfully in ABL/MYC monoclonal antibody production. KH2 is also the first example of a monospecific antibody that directly binds to and, by definition, assumes the conformation of the DNA binding region of p53. PMID: 11084873 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 427: Leuk Res. 2000 Dec;24(12):1033-9. Granulocyte-colony stimulating factor induced intranuclear endonuclease in murine leukemia cell line. Handa A, Kashimura T, Yamamoto A, Murohashi I, Bessho M, Hirashima K. Division of Hematology and Infectious Diseases, Department of Internal Medicine, Saitama Medical School, 350-0451, Saitama, Japan. handaa@nih.gov We have reported that murine leukemia cell line (C2M-A5) induced apoptosis by G-CSF. To clarify the mechanism, mRNA expression of apoptosis-related genes was studied. It revealed transient over-expression of c-myc, H-ras and p53 and down-expression of bcl-2. These changes were known as triggers of endonuclease induction. After 96 h culture with G-CSF, apoptosis was occurred simultaneously with endonuclease (37 kd) activation. This endonuclease induced the digestion of double-strand DNA and might be associated with caspase3. Although G-CSF accelerates cell growth and prevents apoptosis in general, it is a contradictory effect. We concluded that G-CSF induced endogenous endonuclease activity in C2M-A5. PMID: 11077117 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 428: Arkh Patol. 2000 Sep-Oct;62(5):11-7. [Small cell carcinoma and carcinoids of the lung: morphology of apoptosis and expression of biomolecular markers of tumor growth] [Article in Russian] Pal'tsev MA, Demura SA, Kogan EA, Jack G, Zende B. I. M. Sechenov Moscow Medical Academy. Neuroendocrine lung tumors (NELT) from 50 patients were studied immunohistochemically. Malignant carcinoid and small-cell lung carcinoma (SCC) have a higher level of apoptosis than ordinary carcinoid. An increase of apoptosis index in NELT coincides with an increase in NELT proliferative activity (Ki-67, Bcl-2, c-myc, p-53) as compared to a typical carcinoid. Phagocytosis of apoptotic bodies was absent in SCC. Classic SCC differs from combined SCC by a higher apoptosis index and lower expression of p-53 and Bcl-2. Metastatic SCC differs from SCC without metastases by lower apoptosis level and higher level of proliferative indices (Ki-67, Bcl-2) of tumor cells. Development of unbalance between apoptosis and proliferation may result from mitosis and apoptosis pathology. PMID: 11076293 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 429: Am J Pathol. 2000 Nov;157(5):1623-31. Immortal human pancreatic duct epithelial cell lines with near normal genotype and phenotype. Ouyang H, Mou Lj, Luk C, Liu N, Karaskova J, Squire J, Tsao MS. Ontario Cancer Institute, University Health Network-Princess Margaret Hospital, Toronto, Ontario, Canada. Immortal epithelial cell lines were previously established after transduction of the HPV16-E6E7 genes into primary cultures of normal pancreatic duct epithelial cells. Single clones were isolated that demonstrated near normal genotype and phenotype. The proliferation of HPDE6-E6E7c7 and c11 cells is anchorage-dependent, and they were nontumorigenic in SCID mice. The cell lines demonstrated many phenotypes of normal pancreatic duct epithelium, including mRNA expression of carbonic anhydrase II, MUC-1, and cytokeratins 7, 8, 18, and 19. These cells have normal Ki-ras, p53, c-myc, and p16(INK4A) genotypes. Cytogenetic studies demonstrated losses of 3p, 10p12, and 13q14, the latter included the Rb1 gene. The wild-type p53 protein was detectable at very low levels consistent with the presence of E6 gene product, and the lack of functional p53 pathway was confirmed by the inability for gamma-irradiation to up-regulate p53 and p21waf1/cip1 protein. The p110/Rb protein level was also not detectable consistent with the expression of E7 protein and haploid loss of Rb1 gene. Despite this, the proliferation of both c7 and c11 cells were markedly inhibited by transforming growth factor-beta1. This was associated with up-regulation of p21cip1/waf1 but not p27kip1. Further studies showed that p130/Rb2 and cyclin D3 were expressed, suggesting that p130/Rb2 may have partially assumed the maintenance of G(1) cell cycle checkpoint regulation. These results indicate that except for the loss of p53 functional pathway, the two clones of HPDE6-E6E7 cells demonstrated a near normal genotype and phenotype of pancreatic duct epithelial cells. These cell lines will be useful for future studies on the molecular basis of pancreatic duct cell carcinogenesis and islet cell differentiation. PMID: 11073822 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 430: Clin Exp Rheumatol. 2000 Sep-Oct;18(5):643-6. Bcl-2, p53 and c-myc expression in juvenile dermatomyositis. Falcini F, Calzolari A, Generini S, Pignone A, Simonini G, Zulian F, Matucci-Cerinic M. Department of Paediatrics, University of Florence, Italy. falcini@cesit1.unifi.it OBJECTIVE: To investigate p53, bcl-2 and c-myc expression in muscle biopsies from children affected with juvenile dermatomyositis (JDM) and to verify a possible dysregulation of programmed cell death in this autoimmune disease. METHODS: Ten muscle biopsies of children affected with JDM were formalin fixed and paraffin embedded. After haematoxylin and eosin staining, immunohistochemistry was performed employing monoclonal antibodies, anti-p53, anti-bcl-2 and anti-myc. Two normal muscle biopsies were studied as controls. RESULTS: In the biopsies of JDM, two different patterns of myofibers damage were observed: the first, with zones characterised by necrosis; and the second, with zones where an apoptotic process was dominant. Immunoreactivity for bcl-2 was positive in 8 out of 10 biopsies. P53 and c-myc expression were not present in any case. No relationship between the degree of bcl-2 immunostaining and the disease course or outcome was observed. CONCLUSIONS: The over-expression of bcl-2 protein in JDM may suggest a dysregulation of apoptosis in myofibers. Further studies are required in order to better understand the role of our data in the pathogenetic pathways of the disease. PMID: 11072611 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 431: Int J Cancer. 2000 Dec 1;88(5):744-50. Analysis of stepwise genetic changes in an AIDS-related Burkitt's lymphoma. Fais F, Fronza G, Roncella S, Inga A, Campomenosi P, Cutrona G, Pezzolo A, Fedeli F, Abbondandolo A, Chiorazzi N, Pistoia V, Ferrarini M. Clinical Immunology Division, National Cancer Institute, Genoa, Italy. ffais@hp380.ist.unige.it In this study, immunoglobulin variable (Ig V) region genes, c-myc re-arrangement and sequence and p53 status were analyzed in clones derived from a Burkitt's lymphoma cell line (LAM) in which it was previously demonstrated that Epstein-Barr virus (EBV) infection occurred late during lymphomagenesis. Such evidence was based on the finding that 2 groups of cellular clones, characterized by the same c-myc re-arrangement but different EBV-fused termini, were obtained from the LAM cell line. The Ig V gene sequences were identical for the 2 groups of clones with different EBV-fused termini. The Ig variable heavy (V(H)) gene sequence displayed a substantial accumulation of point mutations (but no intra-clonal diversification), whereas the productive Ig V lambda (V(lambda)) gene sequence was virtually unmutated. Studies on the Ig V kappa (V(kappa)) locus suggested a receptor revision event (with a switch from kappa to lambda chain production) prior to EBV infection. Likewise, it was determined that the mutations observed in both p53 alleles and in the re-arranged c-myc gene occurred before EBV infection. Based on these findings, we present a model for the various steps of lymphomagenesis. It is proposed that stimulation by an antigen or a superantigen initially favored the clonal expansion and accumulation of other cytogenetic changes, including those involved in receptor editing. These events occurred prior to or during the germinal center (GC) phase of B-cell maturation. Thereafter, possibly upon exit of the cells from the GC, EBV infection occurred, further promoting lymphomagenesis. Copyright 2000 Wiley-Liss, Inc. PMID: 11072243 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 432: Leukemia. 2000 Nov;14(11):1960-6. De novo acute B cell leukemia/lymphoma with t(14;18). Stamatoullas A, Buchonnet G, Lepretre S, Lenain P, Lenormand B, Duval C, Callat MP, Gaulard P, Bastard C, Tilly H. Departement d'Hematologie, Centre Henri Becquerel, Rouen, France. The t(14;18)(q32;q21) translocation is the most common translocation in B cell malignancies being found in 80% of follicular lymphomas and about 20% of diffuse large B cell lymphomas. Only rare cases of de novo acute B cell lymphoblastic leukemia with t(14;18) have been described. We describe five cases of this entity which appears to have very homogeneous clinical, phenotypic and genotypic features. None of these patients had prior history of follicular lymphoma. The disease was characterized by acute clinical features with nodal and/or extranodal disease, massive bone marrow infiltration and rapid increase of circulating blast cells of mature B cell phenotype. All patients disclosed complex chromosomal and molecular abnormalities involving at least the BCL-2 and c-MYC genes. Furthermore, three patients had evidence of BCL-6 involvement and one patient had a p53 mutation. Despite intensive chemotherapy, including for two patients allogeneic bone marrow transplantation in first complete remission, all patients died within a few months. Neuro-meningeal relapse occurred in three of the five patients in spite of neuro-meningeal prophylaxis. De novo leukemia/lymphoma with t(14;18) is a rare entity with a very poor prognosis. Whether early bone marrow transplant could modify the natural history of the disease remains to be determined. An intensive neuro-meningeal prophylaxis appears to be mandatory in these patients. Publication Types: Case Reports PMID: 11069032 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 433: Eur J Pharmacol. 2000 Nov 3;407(3):227-35. Troglitazone induces apoptosis via the p53 and Gadd45 pathway in vascular smooth muscle cells. Okura T, Nakamura M, Takata Y, Watanabe S, Kitami Y, Hiwada K. The Second Department of Internal Medicine, Ehime University School of Medicine, Onsen-gun, Ehime 791-0295, Japan. okura@m.ehime-u.ac.jp Thiazolidinediones, activators of peroxisome proliferator-activated receptor (PPAR)gamma, have been reported to induce apoptosis in many types of cells. In the present study, we investigated the effects of thiazolidinediones, troglitazone, and pioglitazone on the cell growth of vascular smooth muscle cells, and identified a specific effect of troglitazone in addition to PPARgamma activation. Subconfluent rat culture vascular smooth muscle cells were treated with or without PPARgamma activators, troglitazone (1-30 microM), or pioglitazone (1-30 microM) for 72 h. After treatment, cell viability was significantly reduced by troglitazone in concentrations of 5-30 microM but not by pioglitazone. Vascular smooth muscle cells appeared to float and shrink 48 h after treatment with 20 microM of troglitazone. In situ DNA labeling showed that the nuclei of these cells were positively stained, and genomic DNA extracted from the cells showed nucleosomal laddering. Messenger RNA expression levels of c-myc, p21, bax, bcl-2, and bcl-x were not changed by the treatment with troglitazone. In contrast, along with the induction of vascular smooth muscle cell apoptosis, both the mRNA and protein expression levels of p53 and Gadd45 markedly increased in response to troglitazone. These results strongly suggest that troglitazone can induce vascular smooth muscle cell apoptosis and that this effect is caused primarily by activation of the p53 and Gadd45 pathway but not by PPARgamma activation. PMID: 11068018 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 434: Cancer Res. 2000 Oct 15;60(20):5895-901. A modified p53 overcomes mdm2-mediated oncogenic transformation: a potential cancer therapeutic agent. Lin J, Jin X, Page C, Sondak VK, Jiang G, Reynolds RK. Department of Obstetrics and Gynecology, University of Michigan Comprehensive Cancer Center, Ann Arbor 48109, USA. linjia@umich.edu The antiproliferative activities of wild-type (wt) p53 are inhibited by mdm2 (murine double minute2) oncogene product. We tested growth suppression activity of p53 14/19, an engineered p53 variant, which does not bind mdm2 and is completely resistant to the inhibition by mdm2. p53 14/19, unlike wt p53, suppressed the growth of cancer cells that contain amplified mdm2 oncogene efficiently by direct DNA transfection or adenovirus-mediated gene transfer. In addition, p53 14/19 also inhibited the growth of several different cancer cell lines expressing low levels of mdm2 oncogene product as efficiently as wt p53. We further examined the antioncogenic potencies of p53 14/19 in the rat embryo fibroblast cotransformation assay. Addition of wt p53 failed to cause any significant decrease in ras plus mdm2 foci counts. In contrast, cotransfection of p53 14/19 with ras and mdm2 significantly reduced foci number. In similar experiments, cotransfection of wt p53 or 14/19 p53 resulted in significant inhibition of oncogenic transformation in rat embryo fibroblast mediated by an activated ras plus c-myc, adenovirus E1A, or human papillomavirus E7 oncogenes. Therefore, these results suggest that p53 14/19 modified tumor suppressor gene may be a promising therapeutic agent for human cancers that express abnormally high levels of mdm2 oncogene product. PMID: 11059788 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 435: Biosci Biotechnol Biochem. 2000 Sep;64(9):2021-4. Detection of biomarkers for apoptosis in rat liver after perfusion with 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1). Ashida H, Kihara K, Shiotani B, Hashimoto T, Kanazawa K, Danno G. Department of Biofunctional Chemistry, Faculty of Agriculture, Kobe University, Japan. ashida@kobe-u.ac.jp We previously demonstrated that 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) induced apoptosis in primary cultured rat hepatocytes. In this study, we investigated apoptotic biomarkers in rat liver after perfusion with 30 microM Trp-P-1 as preliminary experiments for in vivo study. Induction of c-Myc and p53 protein and the activities of caspase-3, -6, and -8 were detected in Trp-P-1-perfused liver. In addition, Trp-P-1 modulated the DNA binding activity of the apoptosis-related transcription factors, NF-kappaB and AP-1. These results imply a possibility that Trp-P-1 would induce apoptosis in vivo. PMID: 11055418 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 436: Oncogene. 2000 Oct 19;19(44):5054-62. Dual functions of E2F-1 in a transgenic mouse model of liver carcinogenesis. Conner EA, Lemmer ER, Omori M, Wirth PJ, Factor VM, Thorgeirsson SS. Laboratory of Experimental Carcinogenesis, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, MD 20892, USA. Deregulation of E2F transcriptional control has been implicated in oncogenic transformation. Consistent with this idea, we recently demonstrated that during hepatocarcinogenesis in c-myc/TGFalpha double transgenic mice, there is increased expression of E2F-1 and E2F-2, as well as induction of putative E2F target genes. Therefore, we generated transgenic mice expressing E2F-1 under the control of the albumin enhancer/promoter to test the hypothesis that E2F family members may contribute to liver tumor development. Overexpression of E2F-1 resulted in mild but persistent increases in cell proliferation and death during postnatal liver growth, and no increases in hepatic regenerative growth in response to partial hepatectomy. Nevertheless, from 2 months postnatally E2F-1 transgenic mice exhibited prominent hepatic histological abnormalities including preneoplastic foci adjacent to portal tracts and pericentral large cell dysplasia. From 6 to 8 months onward, there was an abrupt increase in the number of neoplastic nodules ('adenomas') with 100% incidence by 10 months. Some adenomas showed evidence of malignant transformation, and two of six mice killed at 12 months showed trabecular hepatocellular carcinoma. Endogenous c-myc was up-regulated in the early stages of E2F-1 hepatocarcinogenesis, whereas p53 was overexpressed in the tumors, suggesting that both E2F-1-mediated proliferation and apoptosis are operative but at different stages of hepatocarcinogenesis. In conclusion, E2F-1 overexpression in the liver causes dysplasia and tumors and suggests a cooperation between E2F-1 and c-myc oncogenes during liver oncogenesis. PMID: 11042693 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 437: Zhonghua Yi Xue Za Zhi. 1998 Aug;78(8):574-7. [Apoptosis versus proliferation activities and relative mechanism in chronic obstructive pulmonary disease] [Article in Chinese] Tao Q, Zhang Z, Xu Y. Respiratory Disease Research Laboratory, Tongji Hospital, Tongji Medical University, Wuhan. OBJECTIVE: To study the roles of apoptosis and proliferation and relative genes expression in chronic obstructive pulmonary disease (COPD) and pulmonary hypertension. METHODS: Immunohistochemical technique was used for the detection of cell proliferation and expression of relative genes. In situ end labeling technique was used for the detection of nucleosomal DNA fragmentation of apoptotic cells, and Northern blot for the detection of expression of c-myc, bcl-2 and p53 genes in the lungs with COPD. RESULTS: Both proliferative cells and apoptotic cells were found in the lungs with COPD or without COPD. In lung tissue with COPD. The proliferation index was increased significantly, whereas the apoptosis index was decreased significantly. Compared with controls, the ratio of proliferation to apoptosis in lungs with COPD was increased by 4 folds, and the expression of c-myc or bcl-2 mRNA was significantly increased by 2.5-3 folds in lungs tissue with COPD. The expression of c-myc and bcl-2 protein was also increased significantly in lungs with COPD, the two antigen were predominantly localized in small pulmonary vessels. The expression of p53 mRNA was significantly decreased by 3 folds in lung tissue with COPD. CONCLUSION: The abnormality of apoptosis versus proliferation activities induced by c-myc, bcl-2 and p53 genes may contribute to pulmonary vascular structural remodeling in COPD. PMID: 11038804 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 438: Oncogene. 2000 Sep 28;19(41):4669-84. The c-Myc-interacting adaptor protein Bin1 activates a caspase-independent cell death program. Elliott K, Ge K, Du W, Prendergast GC. The Wistar Institute, Philadelphia, PA, USA. Cell death processes are progressively inactivated during malignant development, in part by loss of tumor suppressors that can promote cell death. The Bin1 gene encodes a nucleocytosolic adaptor protein with tumor suppressor properties, initially identified through its ability to interact with and inhibit malignant transformation by c-Myc and other oncogenes. Bin1 is frequently missing or functionally inactivated in breast and prostate cancers and in melanoma. In this study, we show that Bin1 engages a caspase-independent cell death process similar to type II apoptosis, characterized by cell shrinkage, substratum detachment, vacuolated cytoplasm, and DNA degradation. Cell death induction was relieved by mutation of the BAR domain, a putative effector domain, or by a missplicing event that occurs in melanoma and inactivates suppressor activity. Cells in all phases of the cell cycle were susceptible to death and p53 and Rb were dispensable. Notably, Bin1 did not activate caspases and the broad spectrum caspase inhibitor ZVAD.fmk did not block cell death. Consistent with the lack of caspase involvement, dying cells lacked nucleosomal DNA cleavage and nuclear lamina degradation. Moreover, neither Bcl-2 or dominant inhibition of the Fas pathway had any effect. In previous work, we showed that Bin1 could not suppress cell transformation by SV40 large T antigen. Consistent with this finding, we observed that T antigen suppressed the death program engaged by Bin1. This observation was interesting in light of emerging evidence that T antigen has roles in cell immortalization and human cell transformation beyond Rb and p53 inactivation. In support of a link to c-Myc-induced death processes, AEBSF, a serine protease inhibitor that inhibits apoptosis by c-Myc, potently suppressed DNA degradation by Bin1. Our findings suggest that the tumor suppressor activity of Bin1 reflects engagement of a unique cell death program. We propose that loss of Bin1 may promote malignancy by blunting death penalties associated with oncogene activation. PMID: 11032017 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 439: Oncogene. 2000 Sep 21;19(40):4611-20. Oncogenes and tumor angiogenesis: the HPV-16 E6 oncoprotein activates the vascular endothelial growth factor (VEGF) gene promoter in a p53 independent manner. Lopez-Ocejo O, Viloria-Petit A, Bequet-Romero M, Mukhopadhyay D, Rak J, Kerbel RS. Vaccine Division, Centre for Genetic Engineering and Biotechnology, Havana, Cuba. Like other types of pre-malignant lesions and carcinoma, angiogenesis is associated with high-grade cervical dysplasia and with invasive squamous carcinoma of the cervix. Vascular endothelial cell growth factor (VEGF) is known to be one of the most important inducers of angiogenesis and is upregulated in carcinoma of the cervix. Human Papilloma Virus 16 (HPV-16) has been etiologically linked to human cervical cancer, and the major oncogenic proteins encoded by the viral genome, E6 and E7, are involved in the immortalization of target cells. Because several oncogenes including mutant ras, EGF receptor, ErbB2/Her2, c-myc and v-src upregulate VEGF expression, we asked whether HVP-16 E6 oncoprotein could act in a similar fashion. We found that HPV-16 E6-positive cells generally express high levels of VEGF message. Furthermore, co-expression of the VEGF promoter-Luc (luciferase) reporter gene with E6 in both human keratinocytes and mouse fibroblast showed that E6 oncoprotein upregulates VEGF promoter activity, and does so in a p53 independent manner. An E6 responsive region which comprises four Sp-1 sites, between -194 and -50 bp of the VEGF promoter, is also necessary for constitutive VEGF transcription. Taken together, our results suggest the possibility that the HPV oncoprotein E6 may contribute to tumor angiogenesis by direct stimulation of the VEGF gene. PMID: 11030150 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 440: Biochem Biophys Res Commun. 2000 Oct 5;276(3):1203-9. Molecular cloning and functional analysis of the promoter region of rat nonmuscle myosin heavy chain-B gene. Yam JW, Chan KW, Li N, Hsiao WL. Department of Biology, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, Kowloon, China. Rat nonmuscle myosin heavy chain-B (r-nmMHC-B) mRNA was previously found downregulated in Rat 6 fibroblasts transformed by mutant p53(val135) [J. W. P. Yam, J. Y. Zheng, and W. L. W. Hsiao (1987) Biochem. Biophys. Res. Commun. 266, 472-480]. Overexpression of exogenous r-nmMHC-B could partially reverse the transforming phenotypes both in vitro and in vivo. The downregulation of r-nmMHC-B was also observed in Rat 6 transformed by c-H-ras and v-myc oncogenes. We cloned a 5.2-kb r-nmMHC-B promoter region. Sequence analysis of -1248 to +1 revealed no TATA box, but did show that it contained CAAT boxes, E12/E47, MyoD, MEF, E2F, CREB, and SP1 binding sites. Based on transient reporter assays, the promoter/enhancer activities were unusually extended to the entire 5.2 kb region in normal Rat 6 cultures, but markedly suppressed in p53(val135)-, and c-H-ras-transformed cells. The activity detected by the reporter assay corresponded to levels of mRNA as analyzed previously by Northern blots in each respective cell line. Thus, the switch-off of the r-nmMHC-B in the transformed cells is very likely controlled by upstream transcriptional factors, which might have been altered in the course of neoplastic transformation. Copyright 2000 Academic Press. PMID: 11027611 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 441: Nippon Rinsho. 2000 Apr;58 Suppl:25-9. [Oncogene and tumor suppressor gene] [Article in Japanese] Nagai H, Harada H, Emi M. Institute of Gerontology, Nippon Medical School. Publication Types: Review Review, Tutorial PMID: 11025969 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 442: J Pathol. 2000 Oct;192(2):207-15. Molecular cytogenetic evaluation of virus-associated and non-viral hepatocellular carcinoma: analysis of 26 carcinomas and 12 concurrent dysplasias. Zondervan PE, Wink J, Alers JC, IJzermans JN, Schalm SW, de Man RA, van Dekken H. Department of Pathology, Josephine Nefkens Institute, Erasmus University Rotterdam, PO Box 1738, 3000 DR Rotterdam, The Netherlands. The worldwide incidence of hepatocellular carcinoma (HCC) is approximately one million cases a year. This makes HCC one of the most frequent human malignancies, especially in Asia and Africa, although the incidence is increasing also in the western world. HCC is a complication of chronic liver disease, with cirrhosis as the most important risk factor. Viral co-pathogenesis makes cirrhosis due to hepatitis B (HBV) and hepatitis C virus (HCV) infection a very important factor in the development of HCC. As curative therapy is often ruled out due to the late detection of HCC, it would be attractive to find parameters which predict malignant transformation in HBV- and HCV-infected livers. This study has used comparative genomic hybridization (CGH) to analyse 26 HCCs (11 non-viral, nine HBV, six HCV) and 12 concurrent dysplasias (five non-viral, five HBV, two HCV). Frequent gain (> or =25% of all tumours) was detected, in decreasing order of frequency, on 8q (69%), 1q (46%), 17q (46%), 12q (42%), 20q (31%), 5p (27%), 6q (27%), and Xq (27%). Frequent loss (> or =25% of all tumours) was found, in decreasing order of frequency, on 8p (58%), 16q (54%), 4q (42%), 13q (39%), 1p (35%), 4p (35%), 16p (35%), 18q (35%), 14q (31%), 17p (31%), 9p (27%), and 9q (27%). Minimal overlapping regions could be determined at multiple locations (candidate genes in parentheses). Minimal regions of overlap for deletions were assigned to 4p14-15 (PCDH7), 8p21-22 (FEZ1), 9p12-13, 13q14-31 (RB1), 14q31 (TSHR), 16p12-13.1 (GSPT1), 16q21-23 (CDH1), 17p12-13 (TP53), and 18q21-22 (DPC4, DCC). Minimal overlapping amplified sites could be seen at 8q24 (MYC), 12q15-21 (MDM2), 17q22-25 (SSTR2, GH1), and 20q12-13.2 (MYBL2, PTPN1). A single high level amplification was seen on 5q21 in an HBV-related tumour. Aberrations appeared more frequent in HBV-related HCCs than in HCV-associated tumours (p=0.008). This was most prominent with respect to losses (p=0.004), specifically loss on 4p (p=0.007), 16q (p=0.04), 17p (p=0.04), and 18q (p=0.03). In addition, loss on 17p was significantly lower in non-viral cancers than in HBV-related HCC (p<0.001). Furthermore, loss on 13q was more prevalent in HCCs in non-cirrhotic livers (p=0.02), thus suggesting a different, potentially more aggressive, pathway in neoplastic progression. A tendency (p=0.07) was observed for loss on 9q in high-stage tumours; no specific changes were found in relation to tumour grade. A subset of the HCC-associated genetic changes was disclosed in the preneoplastic stage, i.e. liver cell dysplasia. This group of dysplasias showed frequent gain on 17q (25%) and frequent loss on 16q (33%), 4q (25%), and 17p (25%). The majority of the dysplasias with alterations revealed genetic changes that were also present in the primary tumour. In conclusion, firstly, this study has provided a detailed map of genomic changes occurring in HCC of viral and non-viral origin, and has suggested candidate genes. Loss on 17p, including the TP53 region, appeared significantly more prevalent in HBV-associated liver cancers, whereas loss on 13q, with possible involvement of RB1, was distinguished as a possible genetic biomarker. Secondly, CGH analysis of liver cell dysplasia, both viral and non-viral, has revealed HCC-specific early genetic changes, thereby confirming its preneoplastic nature. Finally, genes residing in these early altered regions, such as CDH1 or TP53, might be associated with hepatocellular carcinogenesis. PMID: 11004697 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 443: Oncogene. 2000 Sep 14;19(39):4513-22. Implication of multiple mechanisms in apoptosis induced by the synthetic retinoid CD437 in human prostate carcinoma cells. Sun SY, Yue P, Lotan R. Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, TX 77030, USA. The synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) induces apoptosis in several types of cancer cell. CD437 inhibited the growth of both androgen-dependent and -independent human prostate carcinoma (HPC) cells in a concentration-dependent manner by rapid induction of apoptosis. CD437 was more effective in killing androgen-independent HPC cells such as DU145 and PC-3 than the androgen-dependent LNCaP cells. The caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK blocked apoptosis induced by CD437 in DU145 and LNCaP cells, in which increased caspase-3 activity and PARP cleavage were observed, but not in PC-3 cells, in which CD437 did not induce caspase-3 activation and PARP cleavage. Thus, CD437 can induce either caspase-dependent or caspase-independent apoptosis in HPC cells. CD437 increased the expression of c-Myc, c-Jun, c-Fos, and death receptors DR4, DR5 and Fas. CD437's potency in apoptosis induction in the different cell lines was correlated with its effects on the expression of oncogenes and death receptors, thus implicating these genes in CD437-induced apoptosis in HPC cells. However, the importance and contribution of each of these genes in different HPC cell lines may vary. Because CD437 induced the expression of DR4, DR5 and Fas, we examined the effects of combining CD437 and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and Fas ligand, respectively, in HPC cells. We found synergistic induction of apoptosis, highlighting the importance of the modulation of these death receptors in CD437-induced apoptosis in HPC cells. This result also suggests a potential strategy of using CD437 with TRAIL for treatment of HPC. Oncogene (2000) 19, 4513 - 4522. PMID: 11002424 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 444: Clin Cancer Res. 2000 Sep;6(9):3430-3. Elevated caveolin-1 levels in African-American versus white-American prostate cancer. Yang G, Addai J, Ittmann M, Wheeler TM, Thompson TC. Department of Urology, Baylor College of Medicine, Houston, Texas 77030, USA. Clinical studies suggest that African-American (AA) prostate cancer patients manifest a more aggressive form of the disease compared with white prostate cancer patients. However, the biological underpinnings of this potential difference remain unresolved. To address this issue, we used specific quantitative immunostaining protocols to determine whether a panel of biomarkers related to apoptosis including caveolin-1, bcl-2, p53, and c-myc were differentially expressed in AA versus white prostate cancer patients with similar clinical and pathological characteristics. We further attempted to correlate biomarker positivity with proliferation-related markers including Ki-67 labeling index and apoptotic index. Interestingly, our results indicated that only the incidence of caveolin-1 staining was significantly different between these two ethnic/racial groups of prostate cancer patients. The incidence of caveolin-1 staining in white patients was 17% compared with 39% in AA patients (P = 0.0048; Fisher's exact test). In addition, the percentage of caveolin-1-positive prostate cancer cells was also higher in moderately differentiated (Gleason score 6) prostate cancer patients in AA versus whites. Because caveolin-1 has been shown previously to demonstrate antiapoptotic activities in prostate cancer cells, our results suggest that differences in caveolin-1 expression may in part underlie the apparent differences in the clinical virulence of this disease in AA versus white prostate cancer patients. PMID: 10999725 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 445: Br J Haematol. 2000 Sep;110(3):654-62. High cyclin-dependent kinase inhibitors in Bcl-2 and Bcl-xL-expressing CD34+-proliferating haematopoietic progenitors. Marone M, Pierelli L, Mozzetti S, Masciullo V, Bonanno G, Morosetti R, Rutella S, Battaglia A, Rumi C, Mancuso S, Leone G, Giordano A, Scambia G. Department of Obstetrics and Gynecology and Department of Haematology, Catholic University, Rome, Italy. maria.marone@tiscalinet.it We have previously described the isolation of primitive, slow-proliferating progenitors from normal, circulating CD34+ cells by using the fluorescent dye 5-6-carboxyfluorescein diacetate succinimidyl ester (CFDA-SE). CFDA-SE(bright) (primitive) and CFDA-SE(dim) (differentiating) cells were isolated following cytokine stimulation on the basis of their different proliferation rates. In the present work we analysed the expression levels of a number of proteins involved with differentiation, proliferation and survival/apoptosis in CFDA-SE(bright)/CD34+/slow-proliferating cells that were previously defined as progenitors capable of differentiating into different lineages. The aim of this work was to gain a better understanding of our model system in order to define some of the important parameters that regulate differentiation in haematopoietic progenitors. GATA-1 and PU.1 RNA levels were similar in freshly isolated (d 0) CD34+ and in CFDA-SE(bright) (bright) cells, whereas they increased in CFDA-SE(dim) (dim) cells. Accordingly, Nm23 was expressed at higher levels in bright cells. Moreover, bright cells had higher p21WAF1/CIP1, p27KIP1 and p16Ink4 protein levels than dim cells. Consistently, Cdc2 and Cdk2 kinase activity was much higher in the dim than in the slower proliferating bright cells. C-myc and p53 levels were higher in bright cells than in d 0 CD34+ and dim cells, and so was Bcl-xL, which followed the trend we have previously described for Bcl-2. Thus, bright cells, despite having a higher proliferation rate than the starting d 0 CD34+ population, have strikingly elevated levels of cyclin-dependent kinase inhibitors, which are likely to also act as inhibitors of differentiation. PMID: 10997978 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 446: Int J Cancer. 2000 Aug 20;90(4):175-85. Survival of colorectal cancer cell lines treated with paclitaxel, radiation, and 5-FU: effect of TP53 or hMLH1 deficiency. Kennedy AS, Harrison GH, Mansfield CM, Zhou XJ, Xu JF, Balcer-Kubiczek EK. Department of Radiation Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA. Clonogenic survival and early cell death during treatment of human colon carcinoma cells were investigated following X-irradiation (IR) alone, IR followed by 5-FU for 24 h, and Taxol administered 24 h before IR and 5F-U. The investigated cell lines were: HCT116, 40-16 clonally derived from HCT116, and two HCT116 variants: N6CHR3 expressing hMLH1, and TP53 null cells denoted HCT116 p53-/-. The objective was to determine efficacy of the combined treatment and to correlate response with constitutive levels of TP53, WAF1, and hMLH1 proteins, as well as with mRNA levels of the apoptosis-related genes survivin, BNIP3, and MYC. At the end of treatment with 5-FU, the proportion of viable cells was between 0.65 and 0.70 for all cell lines. Additional cell loss occurred in 40-16 and HCT116 p53-/- cells following administration of Taxol before IR and 5-FU. Radiation sensitivity was unaffected by combined treatments, except for Taxol, irradiation, and 5-FU sequence in the HCT116 p53-/- and 40-16 cell lines, where radiation sensitivity determined by clonogenic survival curve slopes was doubled or quadrupled, respectively. Under our present experimental conditions, treatment response did not correlate with TP53 or hMLH1 status, but was associated with apoptosis-related genes, most notably BNIP3. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 175-185 (2000). Copyright 2000 Wiley-Liss, Inc. PMID: 10993958 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 447: J Orthop Sci. 2000;5(2):150-6. Apoptosis of articular chondrocytes in rheumatoid arthritis and osteoarthritis: correlation of apoptosis with degree of cartilage destruction and expression of apoptosis-related proteins of p53 and c-myc. Yatsugi N, Tsukazaki T, Osaki M, Koji T, Yamashita S, Shindo H. Department of Orthopaedic Surgery, Nagasaki University School of Medicine, Nagasaki, Japan. To investigate the relationship of chondrocyte apoptosis and cartilage destruction, we performed in situ nick end labeling (ISNEL), electron microscopy, and immunohistochemistry against apoptosis-related proteins, p53 and c-myc, in the articular cartilages of patients with rheumatoid arthritis (RA; n = 12) and osteoarthritis (OA; n = 12), and in control articular cartilages from patients with femoral neck fracture (n = 8). The distribution of stained chondrocytes was evaluated semiquantitatively in relation to the degree of cartilage destruction. ISNEL-positive chondrocytes with apoptotic morphological features were identified in a relatively early phase of cartilage destruction, and correlated positively and significantly in a number with the degree of cartilage degeneration. Comparison of RA and OA revealed a significantly greater number of ISNEL-positive chondrocytes in RA cartilage. In contrast, the specimens of normal subjects contained few cells with apoptotic changes. Similarly to the distribution of ISNEL staining, the expression of p53 and c-myc proteins was observed in chondrocytes within the degraded lesions, and showed a positive correlation with the number of ISNEL-stained cells. These results suggest that the degree of chondrocyte apoptosis is closely related to cartilage destruction and that chondrocytes in RA more readily undergo apoptosis than those in OA. The expression of p53 and c-myc proteins in ISNEL-positive areas may reflect the involvement of these proteins in the apoptotic process in articular chondrocytes in inflammatory arthritis. PMID: 10982649 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 448: J Biomater Sci Polym Ed. 2000;11(6):633-46. Modulation of pro- and anti-apoptotic genes in lymphocytes exposed to bone cements. Granchi D, Ciapetti G, Filippini F, Stea S, Cenni E, Pizzoferrato A, Toni A. Laboratorio di Fisiopotologia Degli Impianti Ortopedici, Bologna, Italy. donatella.granchi@ior.it The ability of bone cements to modify the apoptotic program in activated immune cells and the mechanisms by which they act were evaluated. Mononuclear cells were collected from healthy individuals, cultured for 4 and 24 h with phytohemoagglutinina-P and cement extracts and then tested to assess: (a) cell viability; (b) early apoptotic events, by Annexin V/propidium iodide staining; and (c) the expression of pro- (p53, c-myc, ICE) and anti-apoptotic (bcl-2) genes. After 4 h three cements were able to increase significantly the percentage of apoptotic cells, while after 24 h no differences were found. The proportion of dead cells was not significantly changed at either culture time. The simultaneous expression of both pro-apoptotic (ICE, c-myc, p53) and antiapoptotic genes (bcl-2) was investigated only with regard to the materials which induced significant changes in apoptosis: two cements induced the p53 expression, while the third down-regulated bcl-2. As apoptosis regulates the balance of immune response, the authors recommend that the interaction between materials and immune cells should be assessed, so that the use of pro-apoptotic materials may be avoided in patients with immune defects. PMID: 10981678 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 449: Haematologica. 2000 Sep;85(9):913-21. BCL-1 rearrangements and p53 mutations in atypical chronic lymphocytic leukemia with t(11;14)(q13;q32). De Angeli C, Gandini D, Cuneo A, Moretti S, Bigoni R, Roberti MG, Bardi A, Castoldi GL, del Senno L. Centro Interdipartimentale di Biotecnologie-Sezione di Studi Biochimici delle Patologie del Genoma Umano; Universita degli Studi, Ferrara, Italy. BACKGROUND AND OBJECTIVES: The translocation t(11;14) (q13;q32), typically described in mantle cell lymphomas (MCL), has also been found in some cases of non-MCL lymphoproliferative disorders, such as splenic lymphoma with villous lymphocytes (SLVL), multiple myeloma (MM), prolymphocytic leukemia (PLL), typical and atypical chronic lymphocytic leukemia (CLL and aCLL). In order to define better the genetic features of aCLL with t(11;14), which could represent a distinct disease subset, we looked for genetic lesions in the BCL-1 locus and in BCL-2, BCL-6, c-myc and p53 genes. DESIGN AND METHODS: We investigated a panel of B-lymphoproliferative disorders with translocation t(11;14)(q13;q32) including nine aCLL, six MCL and one MM. Southern and Northern blot analysis was used to investigate DNA structure and RNA expression; SSCP and direct sequencing were used to detect and characterize p53 point mutations; cytofluorimetric analysis was used to quantify p53 protein. RESULTS: Alterations of BCL-2, BCL-6 and c-myc were not detected. Conversely, BCL-1 rearrangements were present in 4 out of 7 aCLL and in 2 out of 4 MCL. A high incidence of p53 gene alterations was found, almost equivalent in aCLL and MCL. INTERPRETATION AND CONCLUSIONS: Our results indicate that the occurrence of BCL-1 locus lesions in aCLL selected for t(11;14) is as high as in MCL. Interestingly, rearrangements in the mTC1 (minor translocation cluster 1) were only found in aCLL. Therefore, the two B-cell chronic lymphoproliferative disorders share similar molecular rearrangements and the t(11;14) identifies a subset of B-CLL sharing molecular features with MCL and characterized by aggressive clinical evolution. PMID: 10980628 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 450: Genes Dev. 2000 Sep 1;14(17):2185-91. Myc-enhanced expression of Cul1 promotes ubiquitin-dependent proteolysis and cell cycle progression. O'Hagan RC, Ohh M, David G, de Alboran IM, Alt FW, Kaelin WG Jr, DePinho RA. Department of Adult Oncology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, USA. The c-Myc oncoprotein plays an important role in the growth and proliferation of normal and neoplastic cells. To execute these actions, c-Myc is thought to regulate functionally diverse sets of genes that directly govern cellular mass and progression through critical cell cycle transitions. Here, we provide several lines of evidence that c-Myc promotes ubiquitin-dependent proteolysis by directly activating expression of the Cul1 gene, encoding a critical component of the ubiquitin ligase SCF(SKP2). The cell cycle inhibitor p27(kip1) is a known target of the SCF(SKP2) complex, and Myc-induced Cul1 expression matched well with the kinetics of declining p27(kip1) protein. Enforced Cul1 expression or antisense neutralization of p27(kip1) was capable of overcoming the slow-growth phenotype of c-Myc null primary mouse embryonic fibroblasts (MEFs). In reconstitution assays, the addition of in vitro translated Cul1 protein alone was able to restore p27(kip1) ubiquitination and degradation in lysates derived from c-myc(-/-) MEFs or density-arrested human fibroblasts. These functional and biochemical data provide a direct link between c-Myc transcriptional regulation and ubiquitin-mediated proteolysis and together support the view that c-Myc promotes G(1) exit in part via Cul1-dependent ubiquitination and degradation of the CDK inhibitor, p27(kip1). PMID: 10970882 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 451: Histol Histopathol. 2000 Jul;15(3):851-9. Apoptosis regulating genes in neuroendocrine tumors. Liu WH, Wang DG. The Schepens Eye Research Institute and the Department of Ophthalmology, Harvard Medical School, Boston, USA. Neuroendocrine tumors (NETs) are a heterogeneous group of neoplasms. They are relatively uncommon and characterised by a relatively indolent clinical course. The indolent nature of NETs has long been enigmatic and recent advances in apoptosis research have led to speculation regarding the role of programmed cell death in NET tumorigenesis. It is hoped that a fundamental molecular understanding will help explain these variant behaviors that are so evident to the clinician, and ultimately yield novel and more effective therapies. Recent studies have demonstrated that deregulation of programmed cell death may be a critical component in the multistep tumorigenesis of NETs and that the frequent expression of the BCL-2 oncoprotein in these tumors may contribute to their pathogenesis. The genetic complementation of simultaneously deregulated BCL-2 and c-MYC may be implicated in the multistep tumorigenesis of human NETs. It is also clear that numerous cellular gene products can and will be shown to impact upon apoptosis in NETs; some of these may even be molecules identified as oncoproteins or tumor suppressors. The major challenge will be to ascribe primary pathogenetic significance to tumor-associated derangements in expression of these molecules, and hopefully to then exploit our knowledge toward therapeutic benefit. Publication Types: Review PMID: 10963129 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 452: Proc Natl Acad Sci U S A. 2000 Sep 12;97(19):10544-8. Overexpression of MYC causes p53-dependent G2 arrest of normal fibroblasts. Felsher DW, Zetterberg A, Zhu J, Tlsty T, Bishop JM. Division of Oncology, Departments of Medicine and Pathology, Stanford University, Stanford, CA 94305-5115, USA. dfelsher@leland.stanford.edu Overexpression of the proto-oncogene MYC has been implicated in the genesis of diverse human cancers. One explanation for the role of MYC in tumorigenesis has been that this gene might drive cells inappropriately through the division cycle, leading to the relentless proliferation characteristic of the neoplastic phenotype. Herein, we report that the overexpression of MYC alone cannot sustain the division cycle of normal cells but instead leads to their arrest in G(2). We used an inducible form of the MYC protein to stimulate normal human and rodent fibroblasts. The stimulated cells passed through G(1) and S but arrested in G(2) and frequently became aneuploid, presumably as a result of inappropriate reinitiation of DNA synthesis. Absence of the tumor suppressor gene p53 or its downstream effector p21 reduced the frequency of both G(2) arrest and aneuploidy, apparently by compromising the G(2) checkpoint control. Thus, relaxation of the G(2) checkpoint may be an essential early event in tumorigenesis by MYC. The loss of p53 function seems to be one mechanism by which this relaxation commonly occurs. These findings dramatize how multiple genetic events can collaborate to produce neoplastic cells. PMID: 10962037 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 453: J Cancer Res Clin Oncol. 2000 Aug;126(8):441-7. The biology of multiple myeloma. Drach J, Kaufmann H, Urbauer E, Schreiber S, Ackermann J, Huber H. University of Vienna, First Department of Internal Medicine, Austria. johannes.drach@akh-wien.ac.at Multiple myeloma (MM) is a B-cell malignancy originating from pre-switched, follicle center B-lymphocytes which differentiate to plasma cells accumulating in the bone marrow. MM cells are characterized by a profound genetic instability resulting in a complex set of numerical and structural chromosomal abnormalities. Among these abnormalities, translocations involving 14q32, the immunoglobulin heavy-chain locus, are the most frequent aberrations, but translocation partners are remarkably heterogeneous. Chromosome 13q14 may harbor a critical tumor suppressor gene since MM patients with deletion of 13q14 experience short overall survival after conventional-dose and high-dose chemotherapy. Bone marrow stroma cells support growth and survival of MM cells, which in turn influence the bone marrow microenvironment. This is particularly evident by the markedly increased bone marrow vascularization observed in most patients with active MM. Publication Types: Review Review, Tutorial PMID: 10961386 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 454: Oncogene. 2000 Aug 3;19(33):3693-705. Switch from p53 to MDM2 as differentiating human keratinocytes lose their proliferative potential and increase in cellular size. Dazard JE, Piette J, Basset-Seguin N, Blanchard JM, Gandarillas A. Institut de Genetique Moleculaire, (CNRS, UMR 5535), Montpellier, France. p53 transcription factor is mutated in most skin cell carcinomas and in more than 50% of all human malignancies. One of its transcriptional targets is MDM2, which in turn down-regulates p53. The role of the p53/MDM2 regulatory loop upon genotoxic stress is well documented, but less is known about its role in normal tissue homeostasis. We have explored this pathway during the different transitions of the human epidermal differentiation programme and after isolating stem cells, transit amplifying cells or differentiating cells from epidermis. Maximum expression of p53 was found in proliferating keratinocytes. A striking and transient induction of MDM2 and a down-modulation of p53 characterized the transition from proliferation to differentiation in primary human keratinocytes. These changes were delayed in late differentiating carcinoma cells, and were clearly different in suspended primary fibroblasts. Interestingly, these changes correlated with an increase in cell size, at the time of irreversible commitment to differentiation. Induction of MDM2 was also associated with suppression of proliferation in normal, or hyperproliferative, psoriatic epidermis. Moreover, both proteins were induced as keratinocytes were driven to leave the stem cell compartment by c-Myc activation. Overall, our results show a critical regulation of the p53/MDM2 pathway at the epidermal transition from proliferation to differentiation. PMID: 10949923 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 455: J Clin Oncol. 2000 Aug;18(16):2948-56. Oncogenes and male breast carcinoma: c-erbB-2 and p53 coexpression predicts a poor survival. Pich A, Margaria E, Chiusa L. Department of Biomedical Sciences and Human Oncology, Section of Pathology, University of Turin, Italy. pich@molinette.unito.it PURPOSE: To investigate the prognostic value of biomarkers in male breast carcinoma (MBC). PATIENTS AND METHODS: Fifty patients (mean age, 62.2 years) with invasive ductal carcinoma were retrospectively studied. All patients received surgery; 35 had adjuvant postoperative therapy. The median follow-up was 59 months (range, 1 to 230 months). c-myc, c-erbB-2, p53, and bcl-2 proteins were immunohistochemically detected on sections from formalin-fixed, paraffin-embedded tissues using 9E11, CB11, DO7, and bcl-2 124 monoclonal antibodies (mAbs). Estrogen, progesterone, and androgen receptors were detected using specific mAbs. Cell proliferation was assessed by MIB-1 mAb. RESULTS: In univariate analysis, c-myc, c-erbB-2, and p53 protein overexpression was significantly correlated with prognosis. The median survival was 107 months for c-myc-negative and 52 months for c-myc-positive patients (P =.01), 96 months for c-erbB-2-negative and 39 months for c-erbB-2-positive patients (P =.02), and 100 months for p53-negative and 33 months for p53-positive patients (P =.0008). Tumor histologic grade (P =.01), tumor size (P =.02), patient age at diagnosis (P =.03), and MIB-1 scores (P =.0004) also had prognostic value. In multivariate analysis, only c-erbB-2 and p53 immunoreactivity retained independent prognostic significance. All nine patients who did not express c-erbB-2 and p53 proteins were alive after 58 months, whereas none of the 14 patients expressing both proteins survived at 61 months follow-up (P =.0002). CONCLUSION: Overexpression of c-myc, c-erbB-2, and p53 proteins may be regarded as an additional prognostic factor in MBC. The combination of c-erbB-2 and p53 immunoreactivity can stratify patients into different risk groups. PMID: 10944127 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 456: Semin Cancer Biol. 2000 Jun;10(3):173-84. Apoptosis and the liver. Kanzler S, Galle PR. Department of Medicine, Johannes Gutenberg-University, Mainz, Germany. Regulation of the homeostatic balance between cell proliferation and programmed cell death, apoptosis, is essential for development and maintenance of multicellular organisms. Apoptosis is a genetically and evolutionarily highly conserved process. Analysis of the molecular mechanisms of apoptosis has led to a better understanding of many human diseases. Notably in cancer, but also in infectious or autoimmune disease, a deficiency in apoptosis is one of the key events in pathophysiology. On the other hand, overefficient apoptosis, as observed in fulminant liver failure, may be equally harmful for the organism indicating that a tight regulation of the apoptotic machinery is essential for survival. The execution of apoptosis may be initiated by many different signals, either from within or outside the cell involving ligand-receptor interactions, as has been shown for Fas/Fas-ligand, TNF-alpha/TNF-receptor or TGF-beta/TGF-receptor, or potentially by more unspecific signals such as ceramide or DNA damage. During the modulation phase of apoptosis many different genes such as p53, c-myc or Bcl-2/Bax have been shown to able to shift the balance either to cell survival or cell death. Publication Types: Review PMID: 10936067 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 457: Immunity. 2000 Jul;13(1):15-24. Wnt signaling regulates B lymphocyte proliferation through a LEF-1 dependent mechanism. Reya T, O'Riordan M, Okamura R, Devaney E, Willert K, Nusse R, Grosschedl R. Howard Hughes Medical Institute, Department of Microbiology and Immunology, University of California, San Francisco, 94143, USA. Lymphocyte enhancer factor-1 (LEF-1) is a member of the LEF-1/TCF family of transcription factors, which have been implicated in Wnt signaling and tumorigenesis. LEF-1 was originally identified in pre-B and T cells, but its function in B lymphocyte development remains unknown. Here we report that LEF-1-deficient mice exhibit defects in pro-B cell proliferation and survival in vitro and in vivo. We further show that Lef1-/- pro-B cells display elevated levels of fas and c-myc transcription, providing a potential mechanism for their increased sensitivity to apoptosis. Finally, we establish a link between Wnt signaling and normal B cell development by demonstrating that Wnt proteins are mitogenic for pro-B cells and that this effect is mediated by LEF-1. PMID: 10933391 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 458: Anticancer Res. 2000 May-Jun;20(3A):1839-48. Effect of E-2-(4'-methoxybenzylidene)-1-benzosuberone on the 7,12-dimethylbenz[alpha]anthracene-induced onco/suppressor gene action in vivo II: A 48-hour experiment. Perjesi P, Gyongyi Z, Bayer Z. Department of Medical Chemistry, University Medical School of Pecs, Hungary. The cyclic chalcone analogue, E-2-(4'-methoxybenzylidene)-1-benzosuberone (MBB), has been found to show outstanding in vitro cytotoxic activity against P388, L1210, Molt 4/C8 and CEM cells, as well as against a panel of human cell lines. In order to determine whether this promising antineoplastic activity would extend to anticarcinogenic properties, the effect of MBB on the 7,12-dimethylbenz [alpha]anthracene (DMBA)-induced expression of the c-myc, Ha-ras and p53 genes in isolated RNA from the liver, lung, kidney, spleen, thymus, lymph nodes and bone marrow of CBA/Ca inbred mice was investigated. Earlier we had found that administration of MBB can reduce the DMBA-induced 24-hour gene expressions most effectively when it is administered prior to, or simultaneously with, the DMBA-treatment to female CBA/Ca inbred mice. As a continuation of this study, we investigated the effect of MBB on the DMBA-induced gene expressions according to the two protocols in a 48-hour experiment. The 48-hour experiment with female and male CBA/Ca inbred mice also determined the compound which effectively reduced the DMBA-induced c-myc and Ha-ras overexpressions in almost all tissues. While the DMBA-induced gene expressions showed very different patterns, the effectiveness of the two different administrations of MBB was found to be very similar in the two sex groups. At the same time, contrary to the 24-hour experiment, increased p53 gene expression levels could be seen in several tissues in both sex groups. In order to get a better understanding of the effects of MBB on the DMBA-induced gene expressions "long-term" and "follow-up" studies should be performed. PMID: 10928116 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 459: Anticancer Res. 2000 May-Jun;20(3A):1563-6. 1-Nitropyrene induces elevated expression of oncogenes and tumor suppressor genes 24 hours after treatment in CBA/Ca mice. Ember I, Pusztai Z, Gyongyi Z, Kiss I. Department of Preventive Medicine, University Medical School of Pecs, Hungary. In an earlier experiment we found that 1-nitropyrene treatment causes an increase in the expression of certain onco/suppressor genes in different organs of CBA/Ca mice. In order to further study the kinetics and significance of these gene expression changes, we determined the effect of 1-nitropyrene treatment on the expression of c-myc, p53, Ha-ras, N-ras, and Ki-ras genes, 24 hours after treatment. Expression of the ras family did not change during the studied interval, while elevated expression of c-myc and p53 genes was observed in the spleen, bone marrow and lymph nodes (only c-myc in the latter). The results suggest a different pattern for the involvement of the ras genes in 1-nitropyrene-caused carcinogenesis, and also underlines the differences in the organ specificity of chemical carcinogens in humans and in experimental animals. In the present study, we also confirmed the in vivo applicability of early gene expression changes as biomarkers of carcinogenic exposure. PMID: 10928071 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 460: Bioessays. 2000 Aug;22(8):728-37. Roles of BRCA1 and its interacting proteins. Deng CX, Brodie SG. National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA. chuxiad@bdg10.niddk.nih.gov Germline mutations of BRCA1 predispose women to breast and ovarian cancers. BRCA1 contains several functional domains that interact directly or indirectly with a variety of molecules, including tumor suppressors (p53, RB, BRCA2 and ATM), oncogenes (c-Myc, casein kinase II and E2F), DNA damage repair proteins (RAD50 and RAD51), cell-cycle regulators (cyclins and cyclin-dependent kinases), transcriptional activators and repressors (RNA polymerase II, RHA, histone deacetylase complex and CtIP) and others. Mounting evidence indicates that these physical associations are not artifacts; rather, BRCA1 is likely to serve as an important central component in multiple biological pathways that regulate cell-cycle progression, centrosome duplication, DNA damage repair, cell growth and apoptosis, and transcriptional activation and repression. This review examines our understanding of the significance of the interactions between BRCA1 and other proteins, through which BRCA1 maintains genome integrity and represses tumor formation. Published 2000 John Wiley & Sons, Inc. Publication Types: Review Review, Tutorial PMID: 10918303 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 461: Cancer Invest. 2000;18(6):574-83. Burkitt's lymphoma: molecular pathogenesis and treatment. Bishop PC, Rao VK, Wilson WH. Division of Clinical Science, National Cancer Institute, Bethesda, Maryland, USA. Publication Types: Review Review, Tutorial PMID: 10923106 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 462: Cancer Genet Cytogenet. 2000 Jul 1;120(1):58-72. Establishment and characterization of a new cell line derived from a human primary breast carcinoma. Wang CS, Goulet F, Lavoie J, Drouin R, Auger F, Champetier S, Germain L, Tetu B. Cancer Research Center, Centre Hospitalier Universitaire de Quebec, Division of Pathology, Department of Medical Biology, Quebec, Canada. A new cell line, designated HDQ-P1, was successfully established from a primary ductal infiltrating mammary carcinoma by using a 3T3 feeder layer lethally irradiated to 60 Gy. The HDQ-P1 cells have been grown in culture for over 115 passages and have a doubling time of 60 hours. Characterization of the cell line was performed. This included morphology by light and transmission electron microscopy, karyotype, growth rate, telomerase expression, tumor antigen expression, xenograft implantation into nude mice, colony formation in soft agar, TP53 sequencing, and gene copy number of C-MYC, C-ERBB-2, and C-H-RAS oncogenes. The epithelial nature of this cell line was confirmed by ultrastructural analysis, expression of cytokeratins, and epithelial membrane antigen. The HDQ-P1 cells possess an extensively rearranged and polyploid karyotype, with an average of 20 recurrent marker chromosomes. Scatchard analysis demonstrated that both primary tumor and HDQ-P1 cells were estrogen- and progesterone-receptor negative. The HDQ-P1 cells had the same expression of human telomerase reverse transcriptase as other established breast cancer cell lines such as MDA-MB-231, SK-BR-3, and MCF-7. Direct DNA sequencing showed a point mutation which yielded to a stop codon at the amino acid 213 in exon 6 of the TP53 gene. A five-fold amplification of C-MYC was observed in HDQ-P1 cells. No amplification of C-ERBB-2 and C-H-RAS genes were observed. This cell line presents unique characteristics and may prove to be a good experimental model for investigating breast cancer biology. PMID: 10913678 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 463: In Vivo. 2000 May-Jun;14(3):437-9. Deuterium depletion can decrease the expression of C-myc Ha-ras and p53 gene in carcinogen-treated mice. Gyongyi Z, Somlyai G. Department of Public Health, University Medical School of Pecs, Hungary. zoli@pubhealth.pote.hu In spite of the fact that the deuterium concentration is over 10 mmol/l in all living organisms, its possible role has been ignored for six decades. Recent studies have shown that the depletion of the naturally occurring deuterium can result in tumour regression in mice, dogs, cats and humans. The effect of deuterium depletion on gene expression plays a key part in tumour development. The carcinogen, 7,12-dimethylbenz(alpha)anthracene (DMBA), was used to increase gene expression in "short term" investigations. The expression of c-myc, Ha-ras and p53 gene was followed in CBA/Ca sensitive inbred mice drinking tap water or deuterium-depleted water (DDW) after induction. By detecting the RNA expression 48 hours after exposure to the carcinogen it was found that the expression of all genes investigated was inhibited in six different organs (spleen, lung, thymus, kidney, liver and lymph node) in the DDW-treated group. It is suggested that genes playing a key role in the cell cycle regulation and tumour development are sensitive to deuterium depletion. PMID: 10904878 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 464: Oncogene. 2000 Jun 15;19(26):2967-77. p53-independent apoptosis associated with c-Myc-mediated block in myeloid cell differentiation. Amanullah A, Liebermann DA, Hoffman B. Fels Institute for Cancer Research and Molecular Biology, Department of Biochemistry, Temple University School of Medicine, 3307 N. Broad St., Philadelphia, Pennsylvania, PA 19140, USA. Previously we have shown that deregulated expression of c-myc in M1 myeloid leukemic cells blocked IL-6-induced differentiation and its associated growth arrest; however, the cells proliferated at a significantly reduced rate compared to untreated cells. The basis for the increased doubling time of IL-6-treated M1myc cells was found to be due to the induction of a p53-independent apoptotic pathway. The apoptotic response was not completely penetrant; in the same population of cells both proliferation and apoptosis were continuously ongoing. Down-regulation of Bcl-2 was insufficient to account for the apoptotic response, since deregulated expression of Bcl-2 delayed, but did not block, the onset of apoptosis. Furthermore, our results indicated that the IL-6-induced partial hypophosphorylation of the retinoblastoma gene product (Rb), observed in M1myc cells, was not responsible for the apoptotic response. Finally, the findings in M1 cells were extended to myeloid cells derived from the bone marrow of wild type and p53-deficient mice, where the deregulated expression of c-myc was also shown to block terminal differentiation and induce apoptosis independent of p53. These findings provide new insights into how myc participates in the neoplastic process, and how additional mutations can promote more aggressive tumors. Oncogene (2000) 19, 2967 - 2977 PMID: 10871848 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 465: Eur J Endocrinol. 2000 Jul;143(1):15-24. Innovative strategies for the treatment of thyroid cancer. Schmutzler C, Koehrle J. Medizinische Poliklinik, Abteilung Molekulare Innere Medizin und Klinische Forschergruppe, Universitaet Wuerzburg, Roentgenring 11, D-97070 Wuerzburg, Germany. C.Schmutzler@mail.uni-wuerzburg.de Normally, thyroid cancer is a disease with a good prognosis, but about 30% of the tumours dedifferentiate and may finally develop into highly malignant anaplastic thyroid carcinomas with a mean survival time of less than 8 months. Due to the loss of thyroid-specific functions associated with dedifferentiation, these tumours are inaccessible to standard therapeutic procedures such as radioiodide therapy and thyroxine-mediated thyrotrophin suppression. Medullary thyroid carcinomas are also highly aggressive. Here, therapy is limited to surgery, and no alternative is left if patients do not respond to this standard procedure. Obviously, new approaches would be desirable. Several novel approaches are currently being tested for the treatment of thyroid cancer. Many of them utilise methods of gene therapy, but follow different strategies: (1) reintroduction of the tumour suppressor p53 into a background lacking functional p53; (2) suicide gene therapy with ganciclovir and a transduced gene for herpes simplex virus thymidine kinase controlled by the thyroglobulin promoter; (3) strengthening of the antitumour immune response by expression of an adenovirus-delivered interleukin-2 (IL-2) gene; (4) induction of an immune response by DNA vaccination against the tumour marker calcitonin; (5) transduction of the thyroid sodium/iodide transporter gene to make tissues that do not accumulate iodide treatable by radioiodide therapy; (6) blocking of the expression of the oncogene c-myc by antisense oligonucleotides. While these approaches are still tested in vitro or in animal models, first results from pilot studies concerning other novel treatment modalities are available: (7) radioimmunotherapy exploits the carcinoembryonic antigen expressed on medullary thyroid carcinomas to target a radiolabelled antibody to the tumour; and (8) retinoic acid is used for a redifferentiation therapy in the case of thyroid cancer. Hopefully, one or the other of these novel strategies may probably extend after some time the current therapeutic repertoire for thyroid cancers and provide a perspective for otherwise untreatable patients. Publication Types: Review Review, Tutorial PMID: 10870026 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 466: J Pharmacol Exp Ther. 2000 Jun;293(3):982-8. Reactive oxygen species-induced apoptosis in PC12 cells and protective effect of bilobalide. Zhou LJ, Zhu XZ. Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences. Although clinical studies have demonstrated that EGb 761, a standard extract of Ginkgo biloba, was effective in mild-to-moderate dementia of the Alzheimer's disease patients, the mechanism underlying its neuroprotective effect remains unclear. In this study, effects of bilobalide, the main constituent of the nonflavone fraction of EGb 761, on reactive oxygen species (ROS)-induced apoptosis in PC12 cells was studied. Exposure of cells to xanthine (100 microM)/xanthine oxidase (150 mU/ml) (ROS producer) resulted in a characteristic DNA fragmentation and an increase in the apoptosis rate. When p53, c-Myc, Bcl-2, Bcl-x(L), and Bax were measured by flow cytometry and the activities of caspase-1- and caspase-3-like protease determined with Ac-YVAD-AMC or Ac-DEVD-AMC as substrates, the profile of ROS-induced changes in these apoptosis regulatory and effector proteins suggests that elevation of c-Myc, p53, and Bax and activation of caspase-3 play an important role in the apoptosis. When cells were treated with ROS and bilobalide (25-100 microM) simultaneously, a dose-dependent reduction in the apoptotic rate was found. The percentage of cells with positive staining for c-Myc and p53 decreased from 27.8 and 50.1% to 16.7 and 23.2%, respectively, when bilobalide (25 microM) was present. Bilobalide also reduced ROS-induced elevation of Bax and activation of caspase-3 effectively. Our results provide the first direct evidence that bilobalide can protect neurons against oxidative stress. Bilobalide may block the apoptosis in the early stage and then attenuate the elevation of c-Myc, p53, and Bax and activation of caspase-3 in cells. PMID: 10869401 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 467: J Pathol. 2000 Jun;191(2):112-4. Comment on: J Pathol. 2000 Jun;191(2):120-6. Cell cycle and melanoma--two different tumours from the same cell type. Cree IA. Melanoma of the uvea of the eye and melanoma of the skin share a common cell of origin, but differ substantially in their behaviour and response to chemotherapy. There is increasing evidence that this is related to differences in their molecular phenotype, particularly in relation to the expression of cell cycle-associated proteins. Since many cytotoxic agents act by damaging DNA, resistance is often associated with intact mechanisms which allow the neoplastic cells to arrest their growth while DNA is repaired, or to resist apoptosis in response to detection of DNA damage. p53 is important to these processes, but mutation appears to be a less common event in uveal melanoma than in skin melanoma, probably due to the lack of UV exposure in the uvea. There are also differences in proliferation-associated proteins such as c-myc and cyclin D1. Overexpression of the former molecule is associated with a poor prognosis in skin melanoma, but is associated with a good prognosis in uveal melanoma, although there is considerable genetic heterogeneity within each type. While prognostic studies may therefore be of little relevance to individual patients, they continue to inform our understanding of tumour biology. Copyright 2000 John Wiley & Sons, Ltd. Publication Types: Comment Editorial PMID: 10861567 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 468: Oncogene. 2000 May 18;19(22):2678-86. Hepatocellular carcinoma in WHV/N-myc2 transgenic mice: oncogenic mutations of beta-catenin and synergistic effect of p53 null alleles. Renard CA, Fourel G, Bralet MP, Degott C, De La Coste A, Perret C, Tiollais P, Buendia MA. Unite de Recombinaison et Expression Genetique (INSERM U163), Institut Pasteur, 28 rue du Dr. Roux, 75015 Paris, France. The intronless N-myc2 gene was originally identified as the major target of hepatitis virus insertion in woodchuck liver tumors. Here we report that transgenic mice carrying the N-myc2 gene controlled by woodchuck hepatitis virus (WHV) regulatory sequences are highly predisposed to liver cancer. In a WHV/N-myc2 transgenic line, hepatocellular carcinomas or adenomas arose in over 70% of mice, despite barely detectable expression of the methylated transgene in liver cells. Furthermore, a transgenic founder carrying unmethylated transgene sequences succumbed to a large liver tumor by the age of two months, demonstrating the high oncogenicity of the woodchuck N-myc2 retroposon. Stabilizing mutations or deletions of beta-catenin were found in 25% of liver tumors and correlated with reduced tumor latency (P<0.05), confirming the important role of beta-catenin activation in Myc-induced tumorigenesis. The ability of the tumor suppressor gene p53 to cooperate with N-myc2 in liver cell transformation was tested by introducing a p53-null allele into WHV/N-myc2 transgenic mice. The loss of one p53 allele in transgenic animals markedly accelerated the onset of liver cancer (P=0.0001), and most tumors of WHV/N-myc2 p53+/Delta mice harbored either a deletion of the wt p53 allele or a beta-catenin mutation. These findings provide direct evidence that activation of N-myc2 and reduction of p53 levels act synergistically during multistage carcinogenesis in vivo and suggest that different genetic pathways may underlie liver carcinogenesis initiated by a myc transgene. Oncogene (2000). PMID: 10851067 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 469: Ann Oncol. 2000 Apr;11(4):385-91. Downstream molecular determinants of response to 5-fluorouracil and antifolate thymidylate synthase inhibitors. Van Triest B, Pinedo HM, Giaccone G, Peters GJ. Department of Oncology, University Hospital VU, Amsterdam, The Netherlands. Thymidylate synthase (TS) is an essential enzyme for the de novo synthesis of thymidylate and subsequently DNA synthesis. TS has been used as a target for cancer chemotherapy in the development of fluoropyrimidines such as 5-fluorouracil (5-FU) and 5-fluorodeoxyuridine and of novel folate-based TS inhibitors such as ZD1694 (Tomudex, Raltitrexed), ZD9331, LY231514 (ALIMTA, Pemetrexed), AG337 (Thymitaq, Nolatrexed) and AG331. Although TS has been considered as a target for chemotherapy, the precise mechanism by which TS inhibition leads to cell death is still not completely resolved. TS inhibition results in depletion of dTTP, an essential precursor for DNA, and an increase in dUTP. This results in the so-called thymine-less death due to misincorporation of dUTP into DNA; its excision, catalysed by uracil-DNA glycosylase, results in DNA damage. Both this imbalance in dTTP/dUTP and DNA damage can result in induction of downstream events, leading to apoptosis. On the other hand a specific interaction exists between oncogenes and TS, by binding of TS protein to the p53 and c-myc RNA, while wt p53 can also inhibit TS promotor activity. TS inhibition by either 5-FU or antifolates can also result in a depression of TS protein mediated inhibition of TS mRNA translation leading to induction of more TS protein synthesis, and p53 protein may further deregulate this process. These complex indirect and direct interactions between oncogenes and TS may have as yet unclear clinical implications, since most data are based on in vitro or in vivo studies and some results are contradictive. In some preliminary clinical studies evidence was postulated for a combined prognostic role for TS and p53. This knowledge should be used to design clinical studies with the aim to deliver effective treatment to potentially sensitive patients both in the adjuvant setting and in advanced stage disease. Publication Types: Review Review, Tutorial PMID: 10847455 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 470: Front Biosci. 2000 Jun 1;5:D594-601. Cell cycle implications in the pathogenesis of rheumatoid arthritis. Michael VV, Alisa KE. Department of Medicine, Northwestern University, Chicago, IL 60611, USA. Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by hyperplasia of the synovial lining cells, angiogenesis, and infiltration of mononuclear cells resulting in pannus formation, cartilage erosion and ultimately joint destruction. Synovial tissue (ST) fibroblast hyperplasia is reminiscent of tumor-like proliferation and is a major cause of cartilage destruction in the RA joint. The RA joint is replete with cytokines and growth factors which exert a synergistic mitogenic effect on ST fibroblasts. As a result, RA ST fibroblasts exhibit elevated gene expression of proto- oncogenes, such as c-Myc, c-Ras, and c-Jun and apoptosis inhibitors such as Bcl-2. At the same time, RA ST fibroblasts contain mutations in tumor suppressor genes such as p53. The altered rates of proliferation and apoptosis of RA synovial cells result in the hyperplasia of synovial tissue and in concert with the chronic inflammatory environment ultimately lead to the destruction of the RA joint. Publication Types: Review Review, Tutorial PMID: 10833466 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 471: Exp Gerontol. 2000 May;35(3):375-88. Long-term cultured IL-2-dependent T cell lines demonstrate p16(INK4a) overexpression, normal pRb/p53, and upregulation of cyclins E or D2. Siwicki JK, Hedberg Y, Nowak R, Loden M, Zhao J, Landberg G, Roos G. Department of Immunology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland. Acquisition of an immortal phenotype by circumvention of the normal senescence program can be an important step in tumor development and progression. The regulation of life-span checkpoints is complex and abrogation of these processes can occur at different levels. To better understand these mechanisms in long-term cultured lymphocytes we have characterized two human long-term cultured IL-2-dependent T cell lines regarding telomere length, telomerase activity, and the expression of selected cell cycle regulators (pRb, p53, cyclin E, cyclin D1, cyclin D2, cyclin D3, cdk4, p16(INK4a), p21(WAF1), p27(KIP1), c-myc, bcl-2, and NPAT). We compared these cell lines with a primary T lymphoblast population with a limited life span from the same donor. Both T cell lines with extraordinary growth capacity showed telomere length stabilization, high telomerase activity and demonstrated wild-type pattern of pRb and p53 but strong p16(INK4a) protein expression. The growth inhibitory activity of p16(INK4a) seemed to be abrogated by enhanced expression of cyclin D2, cdk4, and c-myc in one T cell line and overexpression of cyclin E in the second T cell line. PMID: 10832057 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 472: Exp Gerontol. 2000 May;35(3):317-29. Tumor suppressors and oncogenes in cellular senescence. Bringold F, Serrano M. Department of Immunology and Oncology, National Center of Biotechnology, E-28049, Cantoblanco, Madrid, Spain. Cyclin-dependent kinase inhibitors p16(INK4a), p21(Cip1), and p27(Kip1) are regarded as key effectors of cellular senescence. In this review, we describe three senescence-inducing pathways involving these inhibitors, namely, the p16(INK4a)/Rb pathway, the p19(ARF)/p53/p21(Cip1) pathway, and the PTEN/p27(Kip1) pathway. We emphasize the participation of tumor suppressors and oncogenes in the regulation of these senescence-inducing pathways. Finally, we discuss the impact of the Ras and Myc oncogenes on the above-mentioned pathways. Publication Types: Review Review, Tutorial PMID: 10832053 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 473: Oncogene. 2000 May 4;19(19):2354-62. Caspases and mitochondria in c-Myc-induced apoptosis: identification of ATM as a new target of caspases. Hotti A, Jarvinen K, Siivola P, Holtta E. Haartman Institute, Department of Pathology, University of Helsinki, Finland. The mechanism(s) of c-Myc transcription factor-induced apoptosis is still obscure. The activation of c-Myc has been found to lead into the processing/activation of caspases (caspase-3), but the significance of this for the cell demise is debatable. Here we report that several targets of caspases (PKCdelta, MDM2, PARP, replication factor C, 70 kDa U1snRNP, fodrin and lamins) are cleaved during c-Myc-induced apoptosis in Rat-1 MycER cells, indicating an important role for caspases in the apoptotic process. We further found that the ATM (ataxia telangiectasia mutated)--protein is a novel key substrate of caspases. In in vitro assays, purified recombinant ATM protein was found to be cleaved by the effector caspases 3 and 7. The functional significance of the ATM cleavage is supported by the finding that ectopic expression of ATM protected in part against apoptosis. We also show that c-Myc-induced apoptosis involves loss of mitochondrial transmembrane potential, release of cytochrome c from mitochondria into the cytosol and subsequent processing of caspase-9. The cleavage of caspase-9 is, however, minimal and a much later event than the processing/activation of caspase-3, suggesting that it is not the apical caspase. Evidence is provided that there is, nevertheless, an upstream caspase(s) regulating the functions of caspase-3 and mitochondria. Additionally, it was found that p53 becomes upregulated, together with its transcriptional targets MDM2 and p21, upon c-Myc induction, but this occurs also at a later time than the activation of caspase-3. PMID: 10822387 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 474: Oncogene. 2000 Apr 27;19(18):2194-204. c-Myc antagonizes the effect of p53 on apoptosis and p21WAF1 transactivation in K562 leukemia cells. Ceballos E, Delgado MD, Gutierrez P, Richard C, Muller D, Eilers M, Ehinger M, Gullberg U, Leon J. Departamento de Biologia Molecular, Unidad Asociada al Centro de Investigaciones Biologicas, Universidad de Cantabria, Spain. c-myc protooncogene positively regulates cell proliferation and overexpression of c-myc is found in many solid tumors and leukemias. In the present study we used the K562 human myeloid leukemia cell line as a model to study the functional interaction between c-Myc and p53. Using two different methods, we generated K562 transfectant cell lines with conditional expression of either c-Myc or p53. The cells expressed the p53Vall35 mutant, which adopts a wild-type conformation at 32 degrees C, while c-Myc induction was achieved with a zinc-inducible expression vector. We found that p53 in wild-type conformation induces growth arrest and apoptosis of K562. Expression of c-Myc significantly attenuated apoptosis and impaired the transcriptional activity of p53 on p21WAF1, Bax and cytomegalovirus promoters. The impairment of p21WAF1 transactivation by c-Myc was confirmed by transfection of a c-Myc-estrogen receptor fusion protein and by induction of c-myc by zinc in transfected cells. Also, p53-mediated up-regulation of p21WAF1 mRNA protein were significantly reduced by c-Myc, while Bax levels were unaffected. Consistently, c-Myc increased cyclin-dependent kinase 2 activity in K562 cells expressing p53 in wild-type conformation. These results suggest that c-Myc overexpression may antagonize the pro-apoptotic function of p53, thus providing a molecular mechanism for the frequently observed deregulation of c-myc in human cancer. PMID: 10822369 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 475: J Biol Chem. 2000 May 19;275(20):15226-31. Induction of neuronal differentiation by p73 in a neuroblastoma cell line. De Laurenzi V, Raschella G, Barcaroli D, Annicchiarico-Petruzzelli M, Ranalli M, Catani MV, Tanno B, Costanzo A, Levrero M, Melino G. Biochemistry Laboratory, IDI-IRCCS, c/o Department of Experimental Medicine, Tor Vergata University, Via Tor Vergata 135, 00133, Italy. The p53-related p73 and p63 genes encode proteins that share considerable structural and functional homology with p53. Despite similarities, their deletion in mice has different outcomes, implying that the three genes may play distinct roles in vivo. Here we show that endogenous p73 levels increase in neuroblastoma cells induced to differentiate by retinoic acid and that exogenously expressed p73, but not p53, is sufficient to induce both morphological (neurite outgrowth) and biochemical (expression of neurofilaments and neural cell adhesion molecule (N-CAM); down-regulation of N-MYC and up-regulation of pRB) markers of neuronal differentiation. This activity is shared, to different extents, by all p73 isoforms, whereas the transcriptionally inactive mutants of p73 isoforms are ineffective. Conversely, blockage of endogenous p73 isoforms with a dominant negative p73 results in the abrogation of retinoid-induced N-CAM promoter-driven transcription. Our results indicate that the p73 isoforms activate a pathway that is not shared by p53 and that is required for neuroblastoma cell differentiation in vitro. PMID: 10809758 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 476: Histol Histopathol. 2000 Apr;15(2):455-62. Comparative study of tumor angiogenesis and immunohistochemistry for p53, c-ErbB2, c-myc and EGFr as prognostic factors in gastric cancer. Sanz-Ortega J, Steinberg SM, Moro E, Saez M, Lopez JA, Sierra E, Sanz-Esponera J, Merino MJ. Departamento de Anatomia Patologica, Hospital Universitario San Carlos, Madrid, Spain. jsanz@hcsc.insalud.es Gastric cancer (GC) continues to be a highly aggressive malignancy with poor prognosis and low survival rates. The survival of patients with GC depends mainly on the stage of the disease, with early GC having a 5 year survival of 90-100% and advanced tumors a 5 year survival of 15-25%. The role of other prognostic factors in these tumors is still under investigation. 28 gastric dysplasia, 45 Early GC and 98 Advanced Gastric Cancers were evaluated for expression of the oncogenes p53, c-ErbB2, c-myc and the EGFr in paraffin-embedded material utilizing Avidin-Biotin immunohistochemistry techniques. In 34 cases of GC microvessel density (MVD) was determined in CD34 stained sections. Statistical correlations with stage, histologic type, differentiation degree, location, size, ploidy patterns and overall survival were done. The Mantel-Cox test was performed to evaluate which factors had an independent prognostic value. Both, tumor angiogenesis and p53 protein expression were statistically associated (95% confidence intervals) with overall survival in patients with GC. p53 protein expression was also correlated with cardial location, nodal involvement and tumor stage. c-ErbB2 may recognize a group of highly aggressive well differentiated adenocarcinomas with worse prognosis. c-myc was also significantly enhanced in well differentiated tumors. EGFr showed no significant associations. Mantel-Cox was performed to compare the prognostic value of tumor stage, p53 protein expression and tumor angiogenesis. Tumor angiogenesis was the most important prognostic indicator to predict overall survival in our series. p53 expression was not independent and did not provide additional prognostic information to tumor stage. Our study suggests that angiogenesis as demonstrated by microvessel counts in CD34 stained sections is a significantly important prognostic factor for predicting survival in gastric cancer. PMID: 10809364 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 477: Biochim Biophys Acta. 1999 Dec 10;1489(1):85-96. Oligonucleotide therapeutics for hematologic disorders. Agarwal N, Gewirtz AM. Department of Internal Medicine, University of Pennsylvania School of Medicine, Philadelphia, USA. During the last decade, the catalogue of known genes responsible for cell growth, development, and neoplastic transformation has expanded dramatically. Attempts to translate this information into new therapeutic strategies for both hematologic and non-hematologic diseases have accelerated at a rapid pace as well. Inserting genes into cells which either replace, or counter the effects of disease causing genes has been one of the primary ways in which scientists have tried to exploit this new knowledge. Strategies to directly downregulate gene expression have developed in parallel with this approach. The latter include triple helix forming oligonucleotides (ODN) and 'antisense' ODN. The latter have already entered clinical trials for a variety of disorders. In this monograph, we review the use of these materials in the treatment of hematologic diseases, particularly myelogenous leukemias. Problems and possible solutions associated with the use of ODN will be discussed as well. Publication Types: Review Review, Tutorial PMID: 10806999 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 478: Growth Factors. 2000;17(4):249-68. Gene response of human skin fibroblasts to urokinase- and tissue-type plasminogen activators. Copeta A, Tavian D, Marchina E, De Petro G, Barlati S. Department of Biomedical Sciences and Biotechnologies, University of Brescia, Italy. In a previous work we have reported evidences on the mitogenic activity of urokinase-type and tissue-type plasminogen activator (u-PA, t-PA) on serum-deprived human dermal fibroblasts. In this work we have studied the transcription-dependent changes of some cell-cycle related genes associated with the biological activity of PAs, as well as the possible involvement of protein tyr kinases (PTK) and/or protein kinase C (PKC) in the mitogenic signal transduction. The data obtained demonstrate that the growth factor activity of PAs is associated with: - a rapid transient activation of early response genes, c-fos, c-jun and c-myc; - the subsequent coordinated down-regulation of p53 and p21CIP1; - the constant expression of the MEK1 mRNA in every phase of the cell cycle. Quiescent (G0) cells did not express c-fos, c-jun, c-myc and cyclin A, but upon stimulation with mitogens (fetal calf serum (FCS), u-PA, t-PA) the cyclin A mRNA expression was observed in concomitance with the activation of DNA synthesis. Therefore u-PA, t-PA and FCS similarly modulate the expression of c-fos, c-jun, c-myc, p53, p21CIP1 and cyclin A with only slight differences likely related to the time required for activation of DNA synthesis. The PAs mitogenic stimulation of serum-starved cells was associated with the internalization of their molecules, as revealed by immunostaining. The biological activity of u-PA, t-PA, as well as that of limiting concentration of FCS (1%), was mediated by PTK and PKC. Conversely, PTK, but not PKC, was involved in the activation of the proliferative response of basic fibroblast growth factor in the same experimental conditions. In conclusion, u-PA and t-PA can utilize two different pathways, one depending on PTK and the other on PKC in a way similar to the mitogenic activity induced by low concentration of FCS (1%). PMID: 10801075 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 479: Toxicol Appl Pharmacol. 2000 May 1;164(3):291-300. Cadmium induces c-myc, p53, and c-jun expression in normal human prostate epithelial cells as a prelude to apoptosis. Achanzar WE, Achanzar KB, Lewis JG, Webber MM, Waalkes MP. Inorganic Carcinogenesis Section, National Cancer Institute at National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 27709, USA. Cadmium is a suspected human prostatic carcinogen shown to induce prostatic tumors and proliferative lesions in rats. The carcinogenic mechanism of cadmium is unknown, but its poor mutagenicity points toward an epigenetic mechanism. Here we studied the effect of cadmium on genes involved in growth regulation of prostate epithelial cell using the human prostate epithelial cell line RWPE-1, which is immortalized but not transformed and is androgen-responsive. Treatment with 10 microM cadmium resulted in transient increases in c-myc and p53 mRNA levels that peaked at 2-fold and 1.4-fold, respectively, compared to control after 2 h. In contrast, c-jun mRNA levels were increased >3-fold after 2, 4, and 6 h and 20-fold after 24 h. DNA synthesis decreased after 24 h of cadmium exposure. Further study revealed a significant increase in apoptosis after 48 h of cadmium exposure. However, approximately 35% of the cells were still viable and appeared normal, indicating this subpopulation was more resistant to cadmium. Furthermore, these resistant cells had 2.5-fold more metallothionein than untreated control cells. This suggests that cadmium could act to select for apoptotic-defective cells in vivo, thereby increasing the likelihood of tumor formation. This work represents the first description of cadmium affecting oncogene expression in a human cell model of a potential in vivo target site of cadmium carcinogenesis. Copyright 2000 Academic Press. PMID: 10799339 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 480: Am J Chin Med. 2000;28(1):57-67. Inhibition of human smooth muscle cell proliferation by gamigeonsim-tang through the transcriptional regulation of cell cycle-controlling genes. Ko SG, Lee KS, Cho KH, Kim YS, Bae HS, Moon SK. Department of Circulatory Internal Medicine, College of Oriental Medicine, Kyung-Hee University, Seoul, Korea. The effects of gamigeonsim-tang (GGT) on cellular proliferation and expression of cell cycle-related genes were investigated in human smooth muscle cell HISM. HISM cells were treated with an aqueous extract of GGT. Cellular proliferation was investigated by an immunocytometric analysis of PCNA expression and a flow cytometric analysis of the cell cycle progression. Reduced expression of PCNA and a significant accumulation of G1 phase cells were observed following treatment, indicating that GGT inhibits cellular proliferation of human smooth muscle cells. To explore whether GGT affects the transcription of cell cycle-regulating genes, we evaluated mRNA expression of p53, p21Waf1 PCNA, Cyclin D1, Cdc2, Histone H3, c-Myc, and c-Fos using a quantitative RT-PCR analysis. While increased expressions of two negative cell cycle regulators, p53 and p21Waf1 were found, reduced expressions of cell cycle stimulators, PCNA, c-Fos, and c-Myc, were identified following treatment. Taken together, our study demonstrates that GGT inhibits cellular proliferation of human smooth muscle cell through the up- and down-regulation of growth-inhibiting and growth-promoting genes, respectively. PMID: 10794117 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 481: Nature. 2000 Apr 20;404(6780):897-900. Comment in: Nature. 2000 Apr 20;404(6780):823-5. Interplay of p53 and DNA-repair protein XRCC4 in tumorigenesis, genomic stability and development. Gao Y, Ferguson DO, Xie W, Manis JP, Sekiguchi J, Frank KM, Chaudhuri J, Horner J, DePinho RA, Alt FW. Howard Hughes Medical Institute, The Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA. XRCC4 is a non-homologous end-joining protein employed in DNA double strand break repair and in V(D)J recombination. In mice, XRCC4-deficiency causes a pleiotropic phenotype, which includes embryonic lethality and massive neuronal apoptosis. When DNA damage is not repaired, activation of the cell cycle checkpoint protein p53 can lead to apoptosis. Here we show that p53-deficiency rescues several aspects of the XRCC4-deficient phenotype, including embryonic lethality, neuronal apoptosis, and impaired cellular proliferation. However, there was no significant rescue of impaired V(D)J recombination or lymphocyte development. Although p53-deficiency allowed postnatal survival of XRCC4-deficient mice, they routinely succumbed to pro-B-cell lymphomas which had chromosomal translocations linking amplified c-myc oncogene and IgH locus sequences. Moreover, even XRCC4-deficient embryonic fibroblasts exhibited marked genomic instability including chromosomal translocations. Our findings support a crucial role for the non-homologous end-joining pathway as a caretaker of the mammalian genome, a role required both for normal development and for suppression of tumours. PMID: 10786799 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 482: Mol Biol (Mosk). 2000 Mar-Apr;34(2):316-25. [Mutation of p53 is necessary for stable transformation of REF52 cells by myc+ras oncogenes] [Article in Russian] Ivanov AV, Kopnin PB, Kondratov RV, Osovskaia VS, Kopnin BP, Chumakov PM. PMID: 10779961 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 483: Mol Cell Biol. 2000 May;20(10):3616-25. UV-Induced stabilization of c-fos and other short-lived mRNAs. Blattner C, Kannouche P, Litfin M, Bender K, Rahmsdorf HJ, Angulo JF, Herrlich P. Forschungszentrum Karlsruhe, Institute of Toxicology and Genetics, 76021 Karlsruhe, Germany. Irradiation of cells with short-wavelength ultraviolet light (UVC) changes the program of gene expression, in part within less than 15 min. As one of the immediate-early genes in response to UV, expression of the oncogene c-fos is upregulated. This immediate induction is regulated at the transcriptional level and is transient in character, due to the autocatalyzed shutoff of transcription and the rapid turnover of c-fos mRNA. In an experiment analyzing the kinetics of c-fos mRNA expression in murine fibroblasts irradiated with UVC, we found that, in addition to the initial transient induction, c-fos mRNA accumulated in a second wave starting at 4 to 5 h after irradiation, reaching a maximum at 8 h, and persisting for several more hours. It was accompanied by an increase in Fos protein synthesis. The second peak of c-fos RNA was caused by an UV dose-dependent increase in mRNA half-life from about 10 to 60 min. With similar kinetics, the mRNAs of other UV target genes (i.e., the Kin17 gene, c-jun, IkappaB, and c-myc) were stabilized (e.g., Kin17 RNA from 80 min to more than 8 h). The delayed response was not due to autocrine cytokine secretion with subsequent autostimulation of the secreting cells or to UV-induced growth factor receptor activation. Cells unable to repair UVC-induced DNA damage responded to lower doses of UVC with an even greater accumulation of c-fos and Kin17 mRNAs than repair-proficient wild-type cells, suggesting that a process in which a repair protein is involved regulates mRNA stability. Although resembling the induction of p53, a DNA damage-dependent increase in p53 was not a necessary intermediate in the stabilization reaction, since cells derived from p53 knockout mice showed the same pattern of c-fos and Kin17 mRNA accumulation as wild-type cells. The data indicate that the signal flow induced by UV radiation addresses not only protein stability (p53) and transcription but also RNA stability, a hitherto-unrecognized level of UV-induced regulation. PMID: 10779351 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 484: IUBMB Life. 2000 Jan;49(1):23-5. Study on the growth inhibition of human multiple myeloma cells by an IL-6Ralpha mutant. Duan J, Cai X, Wang L, Zhang S, Wang J. Institute of Basic Medical Sciences, Beijing, PR China. jbduan@excite.com DM650, a soluble human IL-6Ralpha mutant with mutation of C277D/H280I, was previously shown to exhibit an antagonism to IL-6, which resulted in growth-inhibition of human multiple myeloma cell line AF-10 autocrining as the growth-stimulating factor. We investigated here the nature of the growth inhibition by examining cell apoptosis. Flow-cytometric analysis of the DNA fragmentation demonstrated that 7.2% of the AF-10 cells were apoptotic after 24 h of treatment with DM650. The constitutive gene expression of bcl-2 in AF-10 cells indicated that apoptosis suppressed by IL-6 was independent of bcl-2 regulation. The altered gene expression of c-myc and p53 suggested that a novel apoptosis pathway, other than that suppressed by IL-6, might be triggered by a complex of DM650 and IL-6. PMID: 10772337 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 485: Anticancer Res. 2000 Jan-Feb;20(1A):475-81. Effect of E-2-(4'-methoxybenzylidene)-1-benzosuberone on the 7,12-dimethylbenz[alpha]anthracene-induced onco/suppressor gene action in vivo. I: A 24-hour experiment. Perjesi P, Bayer Z, Ember I. Department of Medical Chemistry, University Medical School of Pecs, Hungary. The cyclic chalcone analogue, E-2-(4'-methoxybenzylidene)-1-benzosuberone (MBB), was found to show outstanding in vitro antineoplastic activity against P388, L1210, Molt 4/C8 and CEM cells as well as against a panel of human tumor cell lines. In order to determine whether this promising antineoplastic activity would extend to anticarcinogenic properties, the effects of MBB on the 7,12-dimethylbenz[alpha] anthracene (DMBA)-induced expression of c-myc, Ha-ras and p53 genes in isolated RNA from liver, lung, kidney, spleen, thymus, lymph nodes and bone marrow of CBA/Ca inbred mice was investigated. DMBA is a well-known chemical carcinogen, which can act as an initiator by causing point mutations in certain oncogenes and tumor suppressor genes. Elevated expression of oncogenes after treatment with DMBA and other carcinogenic chemicals has been noted previously. Administration of MBB simultaneously with DMBA, 24 hours prior to or 24 hours after the DMBA treatment characteristically modified the DMBA-induced expression of the three genes in the 24-hour experiments. The most pronounced suppression effect of MBB could be observed in almost all the investigated tissues when it was administered simultaneously with DMBA. These "short-term" in vivo results support our previous conclusion that MBB can serve as a model molecule for subsequent structural modifications in searching for new effective anticarcinogenic agents. PMID: 10769699 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 486: Oncol Rep. 2000 May-Jun;7(3):629-37. A conditioned medium from a human liposarcoma-derived cell line induces p53-dependent apoptosis in several tumor cell lines. Mancini A, Borrelli A, Masucci MT, Schiattarella A, Filice S, Rashan J, Maggino T. National Cancer Institute, Fondazione Pascale, 80110 Naples, Italy. A novel cell line, named LSA, has been obtained, stabilized, and characterized from a human liposarcoma. These cells have morphological and biochemical features strongly resembling the adipocytes and were able to grow in the Ham's F12 medium, in presence or absence of FCS. A conditioned medium (LSA-CM) was obtained by growing the LSA cells in the F12 medium in the absence of FCS. LSA-CM had cytostatic and cytotoxic effects (apoptosis and necrosis) associated with down-regulation of c-myc and upregulation of p53 in several human cell lines (breast, lung, glioblastoma, etc. ). The MCF-7 and glioblastoma cells were killed by LSA-CM in 5-6 days, whereas the same cells were killed by LSA-CM co-incubated with low doses of cisplatin in 30 h. LSA-CM peri-tumoral injections for 15 days in Balb-c-fc3H mice affected by mammary tumors, resulted in the rapid disruption of tumors and absence of metastases. In contrast, in the untreated animals the tumor masses were 4 times larger than initial lesions, and numerous metastases were found in the lungs. The toxicity analysis of LSA-CM, performed on three different animal species, showed that LSA-CM is absolutely free of acute, subacute, and subchronic toxicity. The possible use of LSA-CM/cisplatin for cancer treatment is discussed. PMID: 10767381 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 487: Nature. 2000 Mar 30;404(6777):510-4. Comment in: Nature. 2000 Apr 20;404(6780):823-5. DNA repair protein Ku80 suppresses chromosomal aberrations and malignant transformation. Difilippantonio MJ, Zhu J, Chen HT, Meffre E, Nussenzweig MC, Max EE, Ried T, Nussenzweig A. Genetics Department, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. Cancer susceptibility genes have been classified into two groups: gatekeepers and caretakers. Gatekeepers are genes that control cell proliferation and death, whereas caretakers are DNA repair genes whose inactivation leads to genetic instability. Abrogation of both caretaker and gatekeeper function markedly increases cancer susceptibility. Although the importance of Ku80 in DNA double-strand break repair is well established, neither Ku80 nor other components of the non-homologous end-joining pathway are known to have a caretaker role in maintaining genomic stability. Here we show that mouse cells deficient for Ku80 display a marked increase in chromosomal aberrations, including breakage, translocations and aneuploidy. Despite the observed chromosome instabilities, Ku80-/- mice have only a slightly earlier onset of cancer. Loss of p53 synergizes with Ku80 to promote tumorigenesis such that all Ku80-/- p53-/- mice succumb to disseminated pro-B-cell lymphoma before three months of age. Tumours result from a specific set of chromosomal translocations and gene amplifications involving IgH and c-Myc, reminiscent of Burkitt's lymphoma. We conclude that Ku80 is a caretaker gene that maintains the integrity of the genome by a mechanism involving the suppression of chromosomal rearrangements. PMID: 10761921 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 488: Am J Clin Pathol. 2000 Apr;113(4):512-8. Comment in: Am J Clin Pathol. 2000 Dec;114(6):983-5. Expression of c-Myc and p53 correlates with clinical outcome in diffuse large B-cell lymphomas. Chang CC, Liu YC, Cleveland RP, Perkins SL. Department of Pathology, Medical College of Wisconsin, Milwaukee, USA. We performed a retrospective immunohistochemical study of the relationships between clinical manifestations and outcomes of diffuse large B-cell lymphoma (DLBCL) and expression of oncogenic proteins in 21 cases of DLBCL at various clinical stages. Cases of nodal origin expressed p53 more often and presented with high clinical stage more frequently than those of extranodal origin. Expression of c-Myc or p53, but not Bcl-6, Bcl-2, or Bcl-1, showed a statistically significant positive correlation with high clinical stage at presentation and with high or high-intermediate risk. Coexpression of c-Myc and p53 occurred in 7 of 12 patients with high clinical stage but was absent in patients with low clinical stage; coexpression was more frequent in patients with high or high-intermediate risk than in patients with low or low-intermediate risk. Four patients with this coexpression pattern demonstrated an unusually aggressive clinical course (median survival, 7 months). Coexpression of c-Myc and p53 seems to be a better indicator than the MIB1 proliferative index for identification of a cohort of aggressive disease in patients with DLBCL. PMID: 10761452 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 489: Cell Death Differ. 2000 Mar;7(3):262-71. Ceramide-induced cell death is independent of the Fas/Fas ligand pathway and is prevented by Nur77 overexpression in A20 B cells. Bras A, Albar JP, Leonardo E, de Buitrago GG, Martinez-A C. Departamento de Microbiologia e Imunologia, Centro de Citologia Experimental, Universidade do Porto, 4100 Porto, Portugal. The role of ceramide in triggering apoptosis is still a matter of debate. While in some experimental systems, ceramide was shown to mediate Fas-induced cell death, in other instances it was claimed to induce the expression of Fas ligand (FasL), killing cells in a caspase-dependent fashion. We found that, in mature A20 B cells, ceramide-induced apoptosis is independent of the caspase pathway, since we observed no ICE-like, CPP32-like and Mch2 activities and no PARP proteolysis. Moreover, we were unable to protect these cells from ceramide-induced apoptosis using caspase inhibitors, while they blocked Fas-induced apoptosis and no FasL induction could be detected following ceramide treatment. These results suggest that ceramide does not induce apoptosis through the Fas/FasL pathway. We also found that overexpression of Nur77, a zinc-finger transcription factor described to upregulate FasL, antagonizes ceramide-induced apoptosis, but not Fas-induced apoptosis. This further supports the hypothesis that Fas and ceramide death pathways are independent in A20 cells. Ceramide-induced cell death was associated with increased c-myc, p53, Bax and p27kip1 levels; in contrast, cells transfected with Nur77 (A20Nur77), resistant to ceramide-induced apoptosis, showed a marked downregulation of p53 after ceramide treatment, with neither Bax nor p27kip1 induction. In conclusion, our results suggest that, in the A20 B cell line, Fas and ceramide trigger two distinct pathways and that Nur77 overexpression confers protection against ceramide-mediated apoptosis which correlates with inhibition of p53, Bax and p27kip1 induction. PMID: 10745271 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 490: Zhonghua Er Bi Yan Hou Ke Za Zhi. 1997 Apr;32(2):99-102. [Differentiation-inducing effect of stepholidine and retinoic acid on human head and neck carcinoma] [Article in Chinese] Wang J, Zhao L, Lin D. First Hospital of Third Military Medical College, Chongqing. To observe the differentiation-inducing effect of Stepholidine (ST) and Retinoic Acid (RA) on laryngeal and nasopharyngeal carcinoma, the expression of oncogene (C-myc, bcl-2) protein and tumor suppressor gene (p53) was done by using flow cytometry and ABC immunohistochemical methods combined with image analysis technique. The results indicated that after treated with ST and RA, the cells became well-differentiated, the cell growth was suppressed, contact suppress was partially recovered, colony forming was decreased, protooncogenes (C-myc bcl-2) protein was decreased, tumor suppressor gene (p53) protein was increased. No significant difference was observed between the cells treated with ST and TA. We believed that the Chinese medicine-Stephania might be expected to become a new prospective differentiation inducer in carcinoma of head and neck. PMID: 10743138 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 491: Int J Biochem Cell Biol. 2000 May;32(5):509-17. Karyotypic abnormalities associated with haemopoietic lineage switching are not linked with mutations to p53. Colley SM, Chappell DS, Busfield SJ, Voon DC, Klinken SP. Department of Biochemistry, University of Western Australia, Royal Perth Hospital, Perth, Australia. Leukemic cells can undergo lineage switching to display the phenotypic features of another haemopoietic pathway, as exemplified by B lymphoma and erythroleukemic cell lines generating variants with a monocytic appearance. Unlike the diploid parental lines, the vast majority of myeloid derivative lines examined (12 of 13 lines) were aneuploid. As p53 is involved in the maintenance of chromosomal stability, we investigated the role of p53 in the emergence of abnormal karyotypes in cells which had undergone lineage switching. Single strand conformation polymorphism and sequence analysis of cDNA, together with protein immunoprecipitations, were used to assess the p53 status of parental and variant cell lines. Unexpectedly, four or five monocytic lines with chromosomal alterations contained wild type p53. Conversely, a p53 point mutation found in one aneuploid monocytic line was also present in the diploid parental pre-B cell. These results provide strong evidence that mechanisms other than p53 mutations are responsible for karyotypic abnormalities seen in cells that have undergone lineage switching. PMID: 10736566 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 492: Hepatology. 2000 Apr;31(4):956-65. Implication of Bcl-2 family genes in basal and D-amphetamine-induced apoptosis in preneoplastic and neoplastic rat liver lesions. De Miglio MR, Muroni MR, Simile MM, Calvisi DF, Tolu P, Deiana L, Carru A, Bonelli G, Feo F, Pascale RM. Department of Biomedical Sciences, Division of Experimental Pathology and Oncology, University of Sassari, Italy. Molecular mechanisms of basal and D-amphetamine (AMPH)-induced apoptosis were studied in rat liver nodules, 12 (N12) and 30 (N30) weeks after initiation, and in hepatocellular carcinoma (HCC) induced by diethylnitrosamine in rats subjected to resistant hepatocyte model. Basal apoptosis in hematoxylin/eosin- and propidium iodide-stained sections was higher in nodules and HCC than in normal livers. It sharply increased in all tissues 4 hours after AMPH treatment (10 mg/kg), and declined to basal levels at 8 to 12 hours in liver and N12, but remained high up to 18 hours in N30 and HCC. c-myc, Tgf-alpha, p53, and Bcl-X(S) messenger RNA (mRNA) levels were higher, and Bcl-2 mRNA was lower in N12 and/or N30 and HCC than in normal liver. Four hours after AMPH injection, increase in c-myc and decreases in Bcl-2 and Bcl-X(L) mRNAs occurred in all tissues, whereas p53, Bax, and Bcl-X(S) mRNAs increased in N30 and HCC. These changes disappeared in liver and N12 at 18 hours, but persisted in N30 and HCC. c-Myc, P53, Bcl-2, and Bax proteins in normal liver and HCC +/- AMPH showed similar patterns. Tgf-beta1, Tgf-beta-RIII, CD95, and CD95L mRNA levels underwent slight or no changes in any tissue +/- AMPH. Basal Hsp27 expression was high in nodules and HCC, and was stimulated by AMPH in liver and N12, but not in N30 and HCC. These data suggest a role of dysregulation of Bcl-2 family genes and, at least in atypical lesions, of p53 overexpression, in basal and AMPH-induced apoptosis in nodules and HCCs. Hsp27 does not appear to sufficiently protect atypical lesions against apoptosis. PMID: 10733553 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 493: Cell Mol Biol (Noisy-le-grand). 2000 Feb;46(1):79-88. Expression of apoptosis and cell cycle related genes in proliferating and colcemid arrested cells of divergent lineage. Gallaher BW, Berthold A, Klammt J, Knupfer M, Kratzsch J, Bartsch M, Kiess W. Children's Hospital, University of Leipzig, Germany. Progression through the cell cycle and redirection of cells towards programmed cell death (apoptosis) are tightly inter-related processes. However the requirement for tissue and cell type specificity suggests that a wide variety of mechanisms are used to achieve the same purpose. To examine this issue, we investigated cell cycle (c-myc, p53, p21/WAF) and apoptosis related (bcl-2, bcl-X(L), bax-alpha) gene expression in two cell lines of very different origin under proliferating and apoptosis-inducing conditions. Transformed human osteosarcoma cells (MG63) and non-transformed human kidney embryonal fibroblasts (293-0) were kept in culture in medium containing 10% FCS and growth arrest was induced by the addition of 50 ng/ml colcemid. Colcemid treatment caused growth arrest and elevated expression of cyclin B1 protein in both cell lines. Apoptosis was significantly elevated in both cell lines after colcemid exposure for at least one cell cycle. However the pattern of expression of cell cycle and apoptosis related genes, determined by RT-PCR, was quite different between the two cell lines during exponential growth and cell cycle arrest. Colcemid treatment did not markedly influence c-myc, p53 and p21/WAF expression in MG63 cells but did suppress c-myc and increase p21/WAF in 293-0 cells. Furthermore colcemid treated MG63 cells exhibited elevated bcl-2 and bax-alpha expression while similar treatment of 293-0 cells resulted in decreased bcl-X(L) and slightly increased bax-alpha expression. While growth arrest and apoptosis were induced in both MG63 and 293 cells following colcemid treatment, the differences in gene expression suggest that the mechanism by which these cells determine cell fate is quite different and may determine the sensitivity of different cell populations to anti-neoplastic drug therapy. The distinct patterns of gene expression should be carefully defined before mechanisms of apoptotic cell death are studied. PMID: 10726974 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 494: Exp Hematol. 2000 Mar;28(3):244-55. Interleukin-6 sensitizes multiple myeloma cell lines for apoptosis induced by interferon-alpha. Minami R, Muta K, Ilseung C, Abe Y, Nishimura J, Nawata H. Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan. rrhh@intmed3.med.kyushu-u.ac.jp OBJECTIVE: Interleukin-6 (IL-6) is a multifunctional cytokine affecting growth and survival of normal B cell lineage and multiple myeloma cells. To test the hypothesis that IL-6, as well as other hematopoietic growth factors, may enhance apoptosis of target cells, we investigated the effect of IL-6 on myeloma cells in the presence of IFN-alpha, which is prescribed for patients with multiple myeloma. MATERIALS AND METHODS: Four myeloma cell lines, PCM6, NOP-2, U266, RPMI8226 were tested. We determined the induction of apoptosis by flow cytometry, using an FITC-Annexin V. RESULTS: IFN-alpha induced apoptosis on myeloma cell lines, and this apoptosis was further enhanced in the presence of IL-6, via activation of caspase 3. During induction of this apoptosis, the expression of c-Myc and Fas increased. The addition of IL-6 further increased the expression of Fas, but not that of c-Myc. Bcl-2, Bcl-x, and p53 were not affected by the addition of IL-6 and/or IFN-alpha. Addition of a PI-3-K inhibitor interfered with the enhancing effect of IL-6 on the apoptosis induced by IFN-alpha. CONCLUSION: We propose that IL-6 has the death signal, as well as growth promoting effects, and that PI-3-K may play a key role in the induction of apoptosis by IL-6. PMID: 10720689 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 495: Oncogene. 2000 Feb 21;19(8):1114-22. Comment in: Oncogene. 2000 Feb 21;19(8):966-7. Genetic determinants of response to chemotherapy in transgenic mouse mammary and salivary tumors. Bearss DJ, Subler MA, Hundley JE, Troyer DA, Salinas RA, Windle JJ. Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, TX 78284 USA. Several transgenic mouse tumor models were utilized to explore how specific genetic alterations affect the tumor cell response to chemotherapeutic agents in vivo. Specifically, MMTV-ras transgenic mice were interbred to p53 knock-out mice to create a model for assessing the role of p53 in chemotherapeutic responses. In addition, MMTV-ras tumors were compared to MMTV-myc and MMTV-ras/myc tumors. Mice of each genotype reproducibly develop mammary and/or salivary tumors, but tumor growth dynamics vary considerably between genotypes. MMTV-ras/p53-/- tumors exhibit higher S phase fractions than MMTV-ras/p53+/+ tumors, although both tumor types display very low apoptosis levels. In contrast, MMTV-myc tumors exhibit both high S phase fractions and spontaneous apoptosis levels. Tumor-bearing mice of each genotype were treated with either doxorubicin or paclitaxel, and effects on overall tumor growth, cell cycle distribution and apoptosis were evaluated. Surprisingly, neither agent efficiently induced apoptosis in any of the tumor models, including those with wildtype p53. Rather, tumor responses were mediated primarily by changes in cell cycle distribution. However, the spontaneous apoptosis levels did serve as a predictor of tumor growth response, in that only those tumors with high pretreatment apoptosis levels underwent significant regression following treatment with either agent. PMID: 10713698 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 496: Oncogene. 2000 Feb 21;19(8):1065-71. Comment in: Oncogene. 2000 Feb 21;19(8):966-7. Dual regulation of proliferation and apoptosis: c-myc in bitransgenic murine mammary tumor models. Jamerson MH, Johnson MD, Dickson RB. The Lombardi Cancer Center, Georgetown University Medical Center, Georgetown University, Washington DC 20007, USA. Recent progress in the study of c-Myc has convincingly demonstrated that it possesses a dual role in regulating both proliferation and apoptosis; however, the manner in which c-Myc influences these cellular response pathways remains incompletely characterized. Deregulation of c-Myc expression, via many mechanisms, is a common feature of multiple cancers and is an especially prominent feature of many breast cancers. Of significant interest to those who study mammary gland development and neoplasia is the unresolved nature and contribution of apoptosis to breast tumorigenesis. Recently, the use of transgenic mice and gene-knockout mice has allowed investigators to evaluate the pathological mechanisms by which different genes influence tumor development and progression. In this review, we address two distinct c-myc-containing bitransgenic murine mammary tumor models and discuss the contribution and possible future directions for resolution of cancer-relevant molecular pathways influenced by c-Myc. Publication Types: Review Review, Tutorial PMID: 10713691 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 497: Cancer Res. 2000 Feb 15;60(4):1077-83. Relating genotype and phenotype in breast cancer: an analysis of the prognostic significance of amplification at eight different genes or loci and of p53 mutations. Cuny M, Kramar A, Courjal F, Johannsdottir V, Iacopetta B, Fontaine H, Grenier J, Culine S, Theillet C. Genome et Cancer UMR 5535 Centre National de la Recherche Scientifique, Centre de Recherche et de Lutte contre le Cancer Val d'Aurelle-Paul Lamarque, Montpellier, France. Breast cancer heterogeneity can be related directly to its variability at the genetic level. Thus, tumor genotyping could be a valuable approach to define breast tumor subtypes. It has been shown that it is possible to delineate subgroups of breast tumors according to specific sets of DNA amplifications. The aim of the present work was to study the prognostic significance of these DNA amplifications. We studied DNA amplification at eight genes or loci (AIB1, CCND1, EMS1, ERBB2, FGFR1, MDM2, MYC, and RMC20C001) as well as p53 mutations in a series of 640 breast cancer patients who had not received presurgical therapy and analyzed the correlations with survival DNA amplification was assessed by Southern blotting and was scored positive when exceeding three to five copies. Mutations in the p53 gene were searched by four-color fluorescent single. strand conformational polymorphism, using an automated sequencer. Of the nine genetic alterations tested, four (CCND1, EMS1, FGFR1, and p53 mutations) showed a significant association with reduced disease-free (DFS) and/or overall survival (OVS) in the unselected set of patients by univariate test. Correlations for p53 were found only when selecting mutations in exons 5 or 7. Analysis of node-negative and -positive subgroups of patients showed that MDM2 amplification and p53 mutations bore prognostic significance in node-negative patients, whereas amplification of CCND1, EMS1, and FGFR1 correlated with poor outcome in node-positive patients. Multivariate analysis on an unselected set of patients retained significance for the amplification of EMS1, FGFR1, and MDM2 with DFS, of CCND1 with OVS, and of RMC20C001 with both DFS and OVS. Interestingly, stratified analysis according to nodal status confirmed results obtained in the univariate tests: significance of MDM2 amplification and p53 mutations in node-negative and that of CCND1, EMS1, and FGFR1 in node-positive patients. We also observed an association between the number of genetic alterations observed in a tumor and poor prognosis. Patients with two or more amplified loci had a worsened outcome. Strongly correlating coamplifications such as CCND1 and FGFR1, as well as ERBB2 and MYC, were associated with a significant reduction of patient survival, thus indicating cooperative effects. Our data support the idea that genetic alterations in breast cancer are not only helpful for phenotyping purposes, but can also represent powerful prognostic indicators in the clinical practice. PMID: 10706127 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 498: Cancer Genet Cytogenet. 2000 Mar;117(2):97-103. Genetic alterations of gastric cancer: comparative genomic hybridization and fluorescence In situ hybridization studies. Koo SH, Kwon KC, Shin SY, Jeon YM, Park JW, Kim SH, Noh SM. Department of Clinical Pathology, Chungnam National University Hospital, Taejon, South Korea. Genetic changes leading to the development of gastric cancers are still in dispute. In the following study, we used comparative genomic hybridization (CGH) to screen for DNA copy number changes along all chromosomes in 37 gastric carcinomas, and fluorescence in situ hybridization (FISH) with the C-MYC and TP53 probes in 14 cases for comparison. The aim of this study was to identify those chromosome regions that contain genes important for the development of gastric carcinomas and to identify genetic markers associated with tumor progression. The most often involved gains were 2q, 7pq, 8pq, 13q, 17q, 18q, and 20pq. The most commonly deleted regions were 17p. The pattern of genetic changes was different depending on the existence of nodal metastasis and histologic types. Gains in 8q and losses in 17p were the most common features of the CGH changes. However, only 3 among the available 10 cases (30%) showed an amplification of the C-MYC gene by FISH. Allelic loss of TP53 was found in 2 of 4 cases (50%). This difference might be due to another rearrangement of these 2 genes which cannot be detected by FISH, or other possible genes in that area may be involved in the tumorigenesis and nodal metastasis of gastric carcinomas. PMID: 10704677 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 499: Eur Cytokine Netw. 2000 Mar;11(1):119-27. Interferon-gamma and its functional receptors overexpression in benign prostatic hyperplasia and prostatic carcinoma: parallelism with c-myc and p53 expression. Royuela M, de Miguel MP, Ruiz A, Fraile B, Arenas MI, Romo E, Paniagua R. Department of Cell Biology and Genetics, University of Alcala, E-28871 Alcala de Henares, Madrid, Spain. The therapeutic potential of IFN-gamma in prostatic cancer has been documented in several reports, although no immunohistochemical studies of this factor and its receptors in the prostate have been reported. The aim of the present study was to investigate the expression of IFN-gamma and its receptor components (IFN-gamma-Ralpha and IFN-gamma-Rbeta) in normal prostate, benign prostatic hyperplasia (BPH) and prostatic cancer (PC), as well as the possible relationship between this factor and the products of the p53 gene (the wild and mutant forms) and the oncogene c-myc, by means of immunochemical techniques (Western blot, ELISA, and quantification of immunostaining in histological sections). In normal prostate, IFN-gamma and its two receptors were expressed in the basal cells of the epithelium and some stromal cells. In BPH specimens, immunostaining of basal epithelial cells was significantly increased for IFN-gamma and its a receptor, whereas stromal cell immunostaining was significantly increased for IFN-gamma and its b receptor. In addition, columnar epithelial cells immunostained for IFNbeta-Rbeta. PC specimens differed from BPH specimens in the significantly increased immunostaining of epithelial cells for IFN-gamma and its two receptors, and the immunostaining of columnar epithelial cells for IFN-gamma-Ralpha. Immunodetection of wild-p53 was weak and limited to some stromal cells in the three types of specimens. Immunostainings for both mutant-p53 and c-myc were negative in normal prostate, and positive in the epithelium and stromal cells of both BPH and PC specimens. Immunostaining intensity in PC was significantly higher than in BPH. These observations suggest that the expression of both mutant-p53 and c-myc, together with other factors, might be involved in the development of prostatic hyperplasia and neoplasia, while the increased expression of IFN-gamma and its receptors could be regarded as an attempt, although insufficient, to inhibit the uncontrolled cell proliferation. PMID: 10705309 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 500: Gastroenterology. 2000 Mar;118(3):507-14. Overexpression of protein kinase C-beta1 isoenzyme suppresses indomethacin-induced apoptosis in gastric epithelial cells. Zhu GH, Wong BC, Slosberg ED, Eggo MC, Ching CK, Yuen ST, Lai KC, Soh JW, Weinstein IB, Lam SK. Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, P.R. China. BACKGROUND & AIMS: We have previously reported that nonsteroidal anti-inflammatory drugs (NSAIDs) could induce apoptosis of gastric epithelial cells both in vivo and in vitro. This study investigated the role of protein kinase C (PKC) isoforms in the regulation of NSAID-induced apoptosis. METHODS: Protein levels of 12 PKC isoforms in AGS cells, in the presence or absence of indomethacin, were determined by Western blot. The effect of PKC-beta1 overexpression by transfection with its complementary DNA (cDNA) on indomethacin-induced apoptosis and apoptosis-related genes, including p53, p21(waf1/cip1), and c-myc, was further investigated. RESULTS: Treatment with indomethacin decreased the abundance of PKC-beta1 and increased that of PKC-beta2, eta, and epsilon, but did not alter the expression of PKC alpha, gamma, zeta, delta, iota, and micro. Overexpression of PKC-beta1 attenuated the apoptotic response of AGS cells to indomethacin, associated with overexpression of p21(waf1/cip1) in both messenger RNA and protein levels. Inhibition of PKC-beta1-mediated overexpression of p21(waf1/cip1) by its antisense cDNA partially reduced the antiapoptotic effect of PKC-beta1. CONCLUSIONS: Indomethacin-induced apoptosis in gastric cancer cells is partly mediated by differential regulation of PKC isoform expression. Enhanced expression of exogenous PKC-beta1 protects against indomethacin-induced apoptosis through up-regulation of p21(waf1/cip1). PMID: 10702201 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 501: J Invest Dermatol. 2000 Mar;114(3):444-55. Normal growth and differentiation in a spontaneously immortalized near-diploid human keratinocyte cell line, NIKS. Allen-Hoffmann BL, Schlosser SJ, Ivarie CA, Sattler CA, Meisner LF, O'Connor SL. Department of Pathology, University of Wisconsin Medical School, Madison 53706, USA. blallenh@facstaff.wisc.edu We report the isolation and characterization of a spontaneously immortalized human keratinocyte cell line, NIKS. The cell line is not tumorigenic in athymic nude mice and maintains cell-type-specific requirements for growth in vitro. NIKS cells express steady-state levels of transforming growth factor-alpha, transforming growth factor-beta1, epidermal growth factor receptor, c-myc, and keratin 14 mRNAs comparable with the parental BC-1-Ep keratinocyte strain. BC-1-Ep and NIKS keratinocytes produce similar levels of cornified envelopes and nucleosomal fragmentation in response to loss of substrata attachment. DNA fingerprinting results confirm that the NIKS cells originated from the parental BC-1-Ep keratinocytes. NIKS cells contain 47 chromosomes due to an extra isochromosome of the long arm of chromosome 8, and the near-diploid karyotype appears to be stable with repeated passage. A fully stratified squamous epithelium is formed by the NIKS keratinocytes in organotypic culture. Ultrastructural analysis of both the parental and immortalized keratinocytes reveals abundant desmosomes, hemidesmosomes, and the production of a basal lamina. Our findings with the NIKS cells support the observation that spontaneous immortalization is not linked to alterations in squamous differentiation or the ability to undergo apoptosis. The NIKS human keratinocyte cell line is an important new tool for the study of growth and differentiation in stratified squamous epithelia. PMID: 10692102 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 502: J Pharmacol Exp Ther. 2000 Mar;292(3):921-8. c-Myc antisense limits rat liver regeneration and indicates role for c-Myc in regulating cytochrome P-450 3A activity. Arora V, Knapp DC, Smith BL, Statdfield ML, Stein DA, Reddy MT, Weller DD, Iversen PL. AVI BioPharma, Corvallis, Oregon, USA. Expression of c-myc protein is associated with cell proliferation. The present study uses antisense oligomers to inhibit c-myc expression in the regenerating rat liver after 70% partial hepatectomy (PH). Antisense phosphorodiamidate morpholino oligomers (novel DNA analogs) were administered i.p. immediately after surgery to block expression of c-myc within the first 24 h after PH. A 20-mer PMO complimentary to the c-myc mRNA at the translation start site was an effective sequence (AVI-4126, 5'-ACGTTGAGGGGCATCGTCGC-3'). A single i.p. dose of 0.5 mg/kg AVI-4126 caused reduction of the regenerating liver c-myc protein in a sequence-specific and dose-dependent manner. Inhibition of c-myc expression resulted in reduction of proliferating cell nuclear antigen and arrested cells in the G(0)/G(1) phase of the cell cycle. The ratio of G(2):G(0) cell populations in the regenerating liver 24 h after PH dropped from 29.1 in saline vehicle-treated rats to 18.0 in rats treated with 2.5 mg/kg AVI-4126. The expression of cell cycle checkpoint protein p53 was inhibited with increasing doses of AVI-4126, but expression of p21(waf-1) was unaffected. The activity of cytochrome P-450 3A2 (CYP3A2) was evaluated by immunoblot analysis and erythromycin N-demethylation. AVI-4126 did not alter CYP3A activity in nonhepatectamized animals but showed a dose-dependent decrease in PH rats. We conclude that AVI-4126, antisense oligomer to c-myc, can reduce cell proliferation in the regenerating rat liver. Furthermore, inhibition of c-myc may indirectly influence the expression of CYP3A. PMID: 10688605 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 503: Proc Natl Acad Sci U S A. 2000 Feb 29;97(5):2105-10. Pw1/Peg3 is a potential cell death mediator and cooperates with Siah1a in p53-mediated apoptosis. Relaix F, Wei X, Li W, Pan J, Lin Y, Bowtell DD, Sassoon DA, Wu X. The Derald H. Ruttenberg Cancer Center, The Brookdale Center for Molecular and Developmental Biology, The Mount Sinai Medical Center, New York, NY 10029, USA. Induction of wild-type p53 in mouse fibroblasts causes cell cycle arrest at the G(1) phase, whereas coexpression of p53 and the protooncogene c-myc induces apoptosis. Although p53 transcriptional activity generally is required for both pathways, the molecular components mediating p53-dependent apoptosis are not well understood. To identify factors that could mediate p53-induced cell death, we used a comparative RNA differential display procedure. We have identified Pw1/Peg3 as a gene product induced during p53/c-myc-mediated apoptosis. Pw1/Peg3 is not induced during p53-mediated G(1) growth arrest nor by c-myc alone. Although it is not clear whether the induction of Pw1/Peg3 depends on p53 activity, we show that Pw1/Peg3 interacts with a p53-inducible gene product Siah1a. We demonstrate that coexpression of Pw1/Peg3 with Siah1a induces apoptosis independently of p53 whereas expression of Pw1/Peg3 or Siah1a separately has no effect on cell death. These data suggest that Siah1a and Pw1/Peg3 cooperate in the p53-mediated cell death pathway. Furthermore, we show that inhibiting Pw1/Peg3 activity blocks p53-induced apoptosis. The observation that Pw1/Peg3 is necessary for the p53 apoptotic response suggests a pivotal role for this gene in determining cell death versus survival. PMID: 10681424 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 504: Int J Oncol. 2000 Mar;16(3):567-76. Major oncogenes and tumor suppressor genes involved in epithelial ovarian cancer (review). Aunoble B, Sanches R, Didier E, Bignon YJ. Laboratoire d'Oncologie Moleculaire, INSERM CRI 9502/EA 2145, Centre Jean Perrin, BP 392, 63011 Clermont-Ferrand, France. Ovarian cancer remains the leading cause of death from gynecologic malignancy in Western countries. This cancer results from a succession of genetic alterations involving oncogenes and tumor suppressor genes which have a critical role in normal cell growth regulation. Mutations and/or overexpression of three oncogenes, HER-2/neu, c-myc and K-ras, and of the tumor suppressor gene p53, have frequently been observed in sporadic ovarian cancer. In the context of high risk families, the most frequently involved genes are BRCA1 and BRCA2. We review the function of these different proteins, the incidence of mutations in their genes in carcinogenesis and as potential prognostic factors in sporadic and hereditary ovarian cancer. Publication Types: Review Review, Tutorial PMID: 10675491 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 505: Biomaterials. 2000 Mar;21(5):521-7. Evaluation of biological responses to polymeric biomaterials by RT-PCR analysis IV: study of c-myc, c-fos and p53 mRNA expression. Kato S, Akagi T, Sugimura K, Kishida A, Akashi M. Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Kagoshima University, Japan. In order to investigate how cells recognize biomaterials, mRNA that was expressed in attached human fibroblasts on various substrates was evaluated. The expressed oncogenes (c-fos and c-myc) and tumor suppressor gene (p53) mRNA were then isolated and detected using the RT-PCR method. As a result, c-fos and c-myc mRNA expression varied with respect to differences in the hydrophilicity-hydrophobicity of the substrates. Both c-fos and c-myc mRNA expression were low in the fibroblasts that had adhered to hydrophilic surfaces. The tendency of c-fos mRNA expression was similar to the adhesion curve of the cells. c-myc mRNA was largely induced in fibroblasts that had adhered to hydrophobic surfaces. p53 mRNA were largely induced in fibroblasts that had adhered to hydrophilic surfaces, while in the cells that had adhered to hydrophobic surfaces, p53 mRNA expression was low. We concluded that the expression of oncogenes and p53 mRNA is a powerful method for studying cell-polymer interactions or the evaluation of the carcinogenic activity of biomaterials. PMID: 10674817 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 506: Eur J Cancer. 1999 Oct;35(10):1546-50. Proto-oncogenes and p53 protein expression in normal cervical stratified squamous epithelium and cervical intra-epithelial neoplasia. Ngan HY, Liu SS, Yu H, Liu KL, Cheung AN. Department of Obstetrics and Gynaecology, Queen Mary Hospital, Hong Kong. hysngan@hkucc.hku.hk The aim of this study was to study the protein expression of six proto-oncogenes (epidermal growth factor receptor (EGFR), c-fms, c-myc, c-kit, c-erbB-2 and pan-ras) and one tumour suppressor gene (TP53), by immunohistochemical staining of normal cervical stratified squamous epithelium and cervical intra-epithelial neoplasia (CIN). Paraffin sections of 45 normal cervical specimens, 38 CIN grade one (CIN1), 37 CIN2 and 43 CIN3 were studied. An immunohistochemical (IHC) score was derived from the intensity of staining and the percentages of cells stained. In normal cervical specimens, a higher IHC score was found with EGFR and c-fms in superficial (S), intermediate (I) and parabasal (PB) cells compared with basal cells. In contrast, a higher IHC score was found with c-erbB-2 in basal cells in normal cervical specimens. Dysplastic cells in CIN had a higher IHC score with c-myc and c-erbB-2 than normal S/I and PB cells. Dysplastic cells had a higher score with EGFR than normal basal cells. However, a higher IHC score with EGFR and c-fms was found in normal S/I cells than dysplastic cells. These findings suggested that EGFR and c-fms were activated in more differentiated normal cells but were less active in less differentiated normal basal cells. However, EGFR was reactivated in dysplastic cells. Meanwhile, c-erbB-2 was activated in less differentiated normal basal cells and dysplastic cells, and was less active in differentiated normal cells. c-myc was activated in dysplastic cells. c-fms was more active in more differentiated normal cells and was not activated in less differentiated or dysplastic cells. c-kit, pan-ras and TP53 were not activated in normal nor dysplastic cervical cells. These results suggest EGFR, c-erbB-2 and c-myc may be important proto-oncogenes in CIN and that antibodies or anti-genes targeted against them may alter the progress of CIN to invasive cancer. PMID: 10673985 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 507: Hum Pathol. 1999 Dec;30(12):1515-9. Myxoid liposarcoma with transition to round-cell lesion-cell cycle regulator genes and telomerase activity characterizing tumor progression: a case report. Jaeger V, Schneider-Stock R, Gerresheim F, Epplen JT, Serra M, Lippert H, Roessner A. Department of Pathology, Otto-von-Guericke University, Magdeburg, Germany. A mixed myxoid/round cell liposarcoma was macrodissected in its 2 histologic components and investigated for genetic differences between its low-grade myxoid and the high-grade round-cell region. For both, we failed to detect p53 gene mutations, loss of heterozygosity at the p53 or Rb genes, and p53 protein expression. The round-cell component showed a high telomerase activity, and an elevated c-myc mRNA and protein expression. The myxoid component was characterized by a lack of telomerase activity and low c-myc mRNA expression, and immunohistochemistry failed to detect the c-myc protein. There was a higher Mib-1 proliferation index in the round-cell portion. The same specific translocation t(12;16) and the fusion transcript type II in both components confirmed the close relationship between myxoid and round-cell liposarcomas. Telomerase activity and increased c-myc expression seem to be helpful molecular markers for characterizing tumor progression in myxoid liposarcoma. Publication Types: Case Reports PMID: 10667432 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 508: Exp Cell Res. 2000 Feb 25;255(1):30-9. Detection of apoptosis induced by topoisomerase inhibitors and serum deprivation in syrian hamster embryo cells. Alexandre S, Rast C, Nguyen-Ba G, Vasseur P. Universite de Metz, Centre des Sciences de l'Environnement, Metz Cedex, F-57070, France. The sensitivity of normal diploid Syrian hamster embryo (SHE) cells to apoptosis was tested after treatment with the topoisomerase inhibitors camptothecin and etoposide and after serum withdrawal. Programmed cell death (PCD) was identified through morphological, biochemical, and molecular changes and compared with that of HL60 cell line. The results showed that topoisomerase inhibitors, which were shown to be potent PCD inducers in the HL60 cell line, induced a weaker apoptotic response in SHE cells than after growth factor deprivation. In addition, serum-free medium, which rapidly induced apoptosis in SHE cells, did not affect the HL60 cell line. In both cell types, PCD was expressed by condensed chromatin, fragmented nuclei, and DNA laddering on electrophoretic gels, an indisputable sign of apoptosis. In apoptotic HL60 cells, the cleavage of 113-kDa poly(ADP-ribose)polymerase (PARP) resulted in the so-called apoptotic 89-kDa fragment and was associated with increased caspase-3 activity. In apoptotic SHE cells, PARP degraded early but the degradation profile was not characterized by the appearance of an 89-kDa fragment. Moreover, no activation of caspase-3 was noted. ZnCl(2), which is known to prevent protease activity responsible for apoptosis features, inhibited PARP cleavage and nuclear modifications induced by apoptotic stimuli in both cell types, but with a higher sensitivity in SHE cells. Apoptosis induced by serum deprivation was linked with c-myc negative regulation in SHE cells, but not with p53 protein accumulation, while topoisomerase inhibitors led to p53 stabilization without any change in c-myc expression. Serum-free medium and topoisomerase inhibitors did not modify c-myc expression in the HL60 cell line. The overall results demonstrated that apoptosis, which is a carefully regulated process of cell death, may proceed through mechanisms varying according to cell type or apoptosis inducer. In addition, markers which are generally considered hallmarks of apoptosis may fail to appear in some cell types. Copyright 2000 Academic Press. PMID: 10666331 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 509: Oncogene. 2000 Jan 20;19(3):468-71. Transcriptional repression of the human p53 gene by hepatitis B viral X protein. Lee SG, Rho HM. Department of Molecular Biology and Research Center for Cell Differentiation, Seoul National University, Korea. Hepatitis B viral X protein (HBx) and the human p53 protein (p53) have been known as a transactivator and as a tumor suppressor, respectively. These two proteins have also been known to interact with each other to neutralize their authentic functions and the p53 represses the HBV enhancer/X promoter activity. Here we report that the promoter activity of the human p53 gene was strongly repressed by the HBx using the chloramphenicol acetyl transferase (CAT) assay. Analyses of serial deletion, site-directed mutagenesis and the heterologous promoter system showed that the site responsible for the repression was the E-box element in the promoter of the p53 gene. In addition, HBx as expected also repressed the activation of the p53 promoter by c-Myc through the E-box element. Northern blot analyses also showed that the expression of the p53 gene in the HepG2-K8 cell line, which expresses HBV genes including HBx, was much more repressed than that of the control cell HepG2. These results with previous data suggest that the shift of the reciprocal inhibitory activities at the levels of protein-protein interaction and transcription between HBx and p53 may play a decisive role in the HBV-related hepatocarcinogenesis. PMID: 10656696 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 510: J Clin Oncol. 2000 Feb;18(3):510-18. Molecular and clinical features of non-Burkitt's, diffuse large-cell lymphoma of B-cell type associated with the c-MYC/immunoglobulin heavy-chain fusion gene. Akasaka T, Akasaka H, Ueda C, Yonetani N, Maesako Y, Shimizu A, Yamabe H, Fukuhara S, Uchiyama T, Ohno H. First Division, Department of Internal Medicine, and Laboratory of Anatomical Pathology, Faculty of Medicine, The Center for Molecular Biology and Genetics, Kyoto University, Kyoto, Japan. PURPOSE: t(8;14)(q24;q32) and/or c-MYC/immunoglobulin heavy-chain (IGH) fusion gene have been observed not only in Burkitt's lymphoma (BL) but also in a proportion of non-BL, diffuse large-cell lymphoma of B-cell type (DLCL). We explored molecular features of DLCL with c-MYC/IGH fusion and the impact of this genetic abnormality on clinical outcome of DLCL. PATIENTS AND METHODS: A total of 203 cases of non-BL DLCL were studied. Genomic DNA extracted from tumor tissues was subjected to long-distance polymerase chain reaction (LD-PCR) using oligonucleotide primers for exon 2 of c-MYC and for the four constant region genes of IGH. RESULTS: Twelve cases (5.9%) showed positive amplification; one had a c-MYC/Cmicro, nine had a c-MYC/Cgamma, and two had a c-MYC/Calpha fusion sequence. Restriction and sequence analysis of the LD-PCR products, ranging from 2.3 to 9.4 kb in size, showed that breakage in the 12 cases occurred within a 1.5-kb region that included exon 1 of c-MYC in combination with breakpoints at the switch regions of IGH (10 of 12). In 10 cases, Myc protein encoded by the fusion genes demonstrated mutations and/or deletions. Six cases had additional molecular lesions in BCL-2 or BCL-6 and/or p53 genes. The age range of the 12 patients was 44 to 86 years, with a median age of 65.5 years. Five patients had stage I/II disease, and seven had stage III/IV disease. Lactate dehydrogenase was elevated in nine of 11 subjects. Seven showed involvement of the gastrointestinal tract. All patients were treated by surgery and/or chemoradiotherapy; six died of the disease within 1 year, resulting in the poorest 1- and 2-year survival rates among DLCL subgroups. CONCLUSION: The c-MYC/IGH fusion gene of DLCL is identical to that of the sporadic type of BL (sBL). DLCL with c-MYC/IGH shares clinical features with sBL but is characterized further by an older age distribution. PMID: 10653866 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 511: J Neurochem. 2000 Feb;74(2):647-58. Kainic acid-induced apoptosis in rat striatum is associated with nuclear factor-kappaB activation. Nakai M, Qin ZH, Chen JF, Wang Y, Chase TN. Experimental Therapeutics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland 20892-1406, USA. The present study evaluated whether nuclear factor-kappaB (NF-kappaB) activation contributes to the apoptotic-like death of striatal neurons induced by kainic acid (KA) receptor stimulation. Intrastriatally infused KA (1.25-5.0 nmol) produced substantial neuronal loss as indicated by an 8-73% decrease in 67-kDa glutamic acid decarboxylase (p<0.05). KA (1.25-5.0 nmol) elicited internucleosomal DNA fragmentation that was inhibited by the AMPA/KA receptor antagonist NBQX (1,2,3,4-tetrahydro-6-nitro-2,3-dibenzo[f]quinoxaline-7-sulfonamide) but not by the NMDA receptor antagonist MK-801. A decrease in IkappaB-alpha protein levels, which was accompanied by an increase in NF-kappaB binding activity, was found from 6 to 72 h after KA (2.5 nmol) infusion. NF-kappaB was composed mainly of p65 and c-Rel as revealed by supershift assay. In addition, c-Myc and p53 increased from five- to sevenfold from 24 to 72 h after KA (2.5 nmol) administration. Immunohistochemistry revealed high levels of c-Myc and p53 immunoreactivity, mainly in medium-sized striatal neurons. Pretreatment with the cell-permeable recombinant peptide NF-kappaB SN50 (5-20 microg) blocked NF-kappaB nuclear translocation, but had no effect on AP-1 binding. NF-kappaB SN50 also inhibited the KA-induced up-regulation of c-Myc and p53, as well as internucleosomal DNA fragmentation. The apoptotic-like destruction of rat striatal neurons induced by KA receptor stimulation thus appears to involve biochemical mechanisms similar to those mediating the excitotoxic response to NMDA receptor stimulation. The present results provide additional support for the view that NF-kappaB activation contributes to c-Myc and p53 induction and subsequent apoptosis in an excitotoxic model of Huntington's disease. PMID: 10646516 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 512: Gut. 2000 Feb;46(2):200-4. Comment in: Gut. 2000 Oct;47(4):597-8. Replication error phenotype, clinicopathological variables, and patient outcome in Dukes' B stage II (T3,N0,M0) colorectal cancer. Curran B, Lenehan K, Mulcahy H, Tighe O, Bennett MA, Kay EW, O'Donoghue DP, Leader M, Croke DT. Department of Pathology, Royal College of Surgeons in Ireland, Dublin, Republic of Ireland. AIMS: To examine the relation between the replication error (RER) phenotype and other genetic events, clinical features, and long term survival in patients with Dukes' B stage II (T3,N0,M0) colorectal cancer. METHODS: RER phenotype was investigated in 159 patients by PCR amplification of microsatellite marker loci on chromosomes 5q, 17p, 17q, and 18q from tumour DNA extracted from archival tissue. Data on activating c-Ki-ras mutations were available from a previous study. Immunohistochemical detection of p53 and c-erbB-2 expression was performed on paraffin wax embedded tissue. RESULTS: Of 159 colorectal cancers studied, 22 (14%) were RER+ while 137 (86%) were RER- for two or more loci. RER+ tumours were more commonly located in the right colon, tended to be larger than RER- tumours, and were more often poorly differentiated than RER- cancers. No significant associations were seen between RER status and the presence of a mutant c-Ki-ras gene, or between RER status and p53, c-erbB-2, or c-myc gene expression. Univariate survival analysis showed that outcome was similar in RER+ and RER- cases. Multivariate survival analysis showed that the relative risk of death for patients with RER+ cancers was 0.95 that of patients with RER- cancers. CONCLUSIONS: The results suggest that, while the RER phenotype may be associated with some differences in tumour pathology (site, size, differentiation), it is not associated with the genetic alterations studied or with significant differences in long term survival. PMID: 10644313 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 513: Gan To Kagaku Ryoho. 1999 Dec;26(14):2162-7. [Molecular biology of ovarian cancer] [Article in Japanese] Tanaka K. Dept. of Obstetrics and Gynecology, Niigata University School of Medicine, Japan. It has been suggested that the accumulation in multiple steps of gene abnormality is related to the malignant transformation of the normal cell. Understanding such abnormalities would be useful in the establishment of effective measures for the early detection and treatment of cancers with poor prognoses. In gynecological malignancies, the prognosis for epithelial ovarian cancer is poor even though great numbers of patients are treated with multimodal therapy. Uncovering the genes associated with the epithelial ovarian cancer crisis could lead to the identification of high risk cases, and accurate screening could open the way to early detection. Among the genes searched to date for abnormalities related to ovarian cancer, BRCA1 is thought to be the most likely candidate for having a causal relation with the familial ovarian cancer syndrome. Publication Types: Review Review, Tutorial PMID: 10635299 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 514: Gan To Kagaku Ryoho. 1999 Dec;26(14):2139-46. [Molecular biology in gastric cancer] [Article in Japanese] Kikuchi K, Ueda M, Kitajima M. Dept. of Surgery, Tokyo Denryoku Hospital, Japan. In gastric cancer, the process of carcinogenesis is thought to occur as a stepwise accumulation of genetic abnormalities. However, the mechanisms of the process of multistage carcinogenesis is still unknown for gastric cancer. Gene abnormalities seen in gastric cancer, including ras, myc, c-erbB-2, met, K-sam and cript are summarized herein. Abnormalities of cancer suppressor genes, including p53, RB and APC are also described. In our studies, the biological malignancy of patients with c-erbB-2 amplification was higher than that of patients without amplification. Moreover, the cases with amplification of c-erbB-2 were found to be highly correlated with distant organ metastasis. However, very little is currently known of the molecular abnormalities leading to gastric cancer. In order to clarify the multiple gene abnormalities in gastric cancer, we used the method of restriction landmark genomic scanning (RLGS). RLGS provides a useful method for genomic analysis of gastric cancer. In the future, new analytical methods that will permit screening of all gene abnormalities at once promise to improve our understanding of the mechanisms of gastric cancer. Publication Types: Review Review, Tutorial PMID: 10635296 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 515: Leuk Res. 2000 Jan;24(1):33-8. Overexpression of Ras, Raf and L-myc but not Bcl-2 family proteins is linked with resistance to TCR-mediated apoptosis and tumorigenesis in thymic lymphomas from TCR transgenic mice. Kobzdej M, Matuszyk J, Strzadala L. Laboratory of Cellular Immunology, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland. Mice with transgenic TCR anti H-Y/Db develop spontaneous thymic tumors with a high frequency (up to 50%). Oncogenicity of TCR transgenes could depend on the deregulated expression of oncoproteins engaged in transduction pathways leading to proliferation or apoptosis. In agreement with this possibility we have found that cells of thymic lymphomas from TCR transgenic mice were largely resistant to TCR-dependent Ca++-mediated apoptosis but not to TCR-independent, p53-mediated (etoposide) apoptosis. Here we show raised expression of Bcl-2 protein in some but not in all thymic lymphoma cell lines. It suggests that the antiapoptotic function of Bcl-2 is not necessary for the process of tumorigenesis and the resistance of these lymphomas to Ca++-mediated apoptosis. On the other hand we show that all thymic lymphomas overexpressed Ras/Raf and L-myc proteins. Stimulation of the Ras/Raf pathway was reported to be required to maintain cell viability by preventing programmed cell death in thymic tumors derived from lck transgenic mice. Similarly, in TCR transgenic lymphomas overexpression of Ras, Raf and L-myc but not Bcl-2 family proteins may be responsible for the resistance of these lymphomas to TCR-mediated apoptosis but not affect p53-mediated apoptosis. PMID: 10634643 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 516: Clin Cancer Res. 1999 Dec;5(12):4111-8. Immunohistochemical expression of fatty acid synthase, apoptotic-regulating genes, proliferating factors, and ras protein product in colorectal adenomas, carcinomas, and adjacent nonneoplastic mucosa. Visca P, Alo PL, Del Nonno F, Botti C, Trombetta G, Marandino F, Filippi S, Di Tondo U, Donnorso RP. Department of Cytopathology, Regina Elena National Cancer Institute of Rome, Italy. The normal mucosa-adenoma-carcinoma sequence in colon pathology provides an attractive model of tumor progression. The role of tumor suppressor genes, oncogenes, and proliferative markers in tumorogenesis has evolved considerably in the last decade. By immunohistochemistry means, we have studied p53, bcl-2, c-myc, p21-ras, ki67, and fatty acid synthase (a fatty-acid-synthesizing enzyme) in normal, dysplastic, and neoplastic mucosa. The results were correlated with clinicopathological features and overall survival (OS). Formalin-fixed, paraffin-embedded archival material from 100 nonconsecutive adenomas and 100 adenocarcinomas (ADCs), including adjacent-to-tumor nonneoplastic mucosa (ANNM), from patients with a 5-year follow-up period were studied. Negative controls were obtained from colon resections for nonneoplastic disease. Fatty acid synthase was associated with ADC (P = 0.0001). p53 protein was associated with high-grade dysplasia adenoma (AHGD), ADC (P = 0.0001), and pT stage (P = 0.003). bcl-2 was associated with adenomas with low-grade dysplasia (P = 0.009); c-myc was associated with ANNM (P = 0.005) and pT stage (P = 0.006). p21-ras was associated with AHGD (P = 0.0001) and ANNM (P = 0.01). Ki67 was associated with AHGD (P = 0.02) and ADC (P = 0.0001). Univariate analysis on neoplastic tissue revealed histological grade, pT stage, pN stage, p21-ras, and p53 to be significant markers of OS; p21-ras, p53, and c-myc were reliable markers when evaluated on ANNM. Multivariate analysis revealed pT stage, pN stage, and p21-ras to be independent prognosticators of OS on ADC; p21-ras and c-myc staining in the ANNM were correlated with worse survival (OS). We suggest that the evaluation in concert of clinicopathological data and immunohistochemical markers on both normal and abnormal colon tissue provides an attractive model of tumor progression; moreover, it may give important messages about the prediction of survival. PMID: 10632348 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 517: Mol Cell Biochem. 1999 Nov;201(1-2):25-32. Diminished energy metabolism and enhanced apoptosis in livers of B6C3F1 mice treated with the antihepatocarcinogen rotenone. Wang C, Youssef J, Saran B, Rothberg PG, Cunningham ML, Molteni A, Badr M. University of Missouri-Kansas City, 64108-2792, USA. Rotenone decreases the incidence of hepatocellular carcinoma and lowers rates of hepatocellular proliferation. In an effort to delineate mechanisms involved, the in vivo effect of rotenone on liver mitochondrial metabolism, apoptotic machinery as well as elements of the hepatic signal transduction pathways were investigated. Mitochondria from livers of male B6C3F1 mice fed a standard diet containing 600 ppm rotenone for 7 days were uncoupled or inhibited when succinate or glutamate plus malate were used as the substrate, respectively. These livers also showed a significant increase in apoptosis compared with control livers. Furthermore, rotenone increased the expression of c-myc mRNA to 5-fold of control values within 3 days, an effect which was still observed (3-fold) after 7 days. Levels of p53 mRNA were also increased 3-fold after 1 day, but declined to control levels by 7 days. Rotenone also caused a transient, yet marked increase in liver particulate glyceraldehyde phosphate dehydrogenase (GAPDH) protein expression, while it did not alter the expression of the cytosolic form of the enzyme. Conversely, mRNA of the proto-oncogene H-ras showed a decline of 35% after 3 days of rotenone treatment, and remained diminished for the duration of the experiment. These data suggest that rotenone may act as an anticancer agent by diminishing mitochondrial bioenergetics which prevents basal hepatocyte proliferation and lowers the threshold for liver cells with DNA damage to undergo apoptosis. PMID: 10630619 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 518: Gynecol Obstet Invest. 2000;49(1):47-51. Overexpression of p53 and HER-2/neu and c-myc in primary fallopian tube carcinoma. Chung TK, Cheung TH, To KF, Wong YF. Department of Obstetrics and Gynaecology, Chinese University of Hong Kong, Prince of Wales Hospital, Sha Tin, N.T., Hong Kong. tonychung@cuhk.edu.hk Primary fallopian tube carcinoma is a rare form of female cancer and the genetic basis of its carcinogenesis remains unclear. Eighteen cases of primary fallopian tube adenocarcinoma were studied. Immunohistochemical staining for p53, HER-2/neu and c-myc genes were performed. Overexpression of p53 was detected in 12 cases (67%), HER-2/neu in 16 cases (89%), and c-myc in 11 cases (61%). The potential relevance of overexpression of the three genes with clinicopathological features was examined, but no significant correlation was found. The high incidence of p53, HER-2/neu and c-myc overexpression in fallopian tube adenocarcinoma suggests these genes may play a role in its tumorigenesis. Copyright 2000 S. Karger AG, Basel PMID: 10629373 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 519: J Steroid Biochem Mol Biol. 1999 Nov;71(1-2):49-61. Gender- and androgen-related influence on the expression of proto-oncogene and apoptotic factor mRNAs in lacrimal glands of autoimmune and non-autoimmune mice. Toda I, Sullivan BD, Wickham LA, Sullivan DA. Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA. Our previous studies have shown that the mRNA levels of c-myb, c-myc, bcl-2 and p53 are higher, and partial Fas antigen (i.e. exons 1-2) lower, in lacrimal tissues of female, as compared to male, MRL/lpr mice, which are a model of Sjogren's syndrome. We have also found that this gender-related difference in bcl-2 and c-myb expression appears to be due to the influence of androgens. To extend these findings, we sought to determine: first, whether these gender- and/or hormone-associated variations in mRNA content are unique to MRL/lpr mice, or are also present in lacrimal glands of other murine strains, including autoimmune NZB/NZW F1 (F1) and non-obese diabetic (NOD), as well as non-autoimmune C3H/HeJ (C3H) and BALB/c, mice; and second, whether the levels of these apoptotic factor mRNAs are altered in lacrimal tissues of mice (i.e. testicular feminized (Tfm) with dysfunctional androgen receptors, as compared to glandular amounts in their 'normal' controls (i.e. Tabby). Lacrimal tissues were obtained from adult mice, which were either untreated or treated with placebo or testosterone for 21 days. Glands were processed for the analysis of proto-oncogene mRNAs by RT-PCR (at exponential phase of amplification) and data were standardized to the corresponding levels of beta-actin mRNA. Our results demonstrate that Fas antigen, Fas ligand, c-myb, c-myc, bcl-2, Bax and p53 mRNAs are present in lacrimal tissues of F1, NOD, C3H, BALB/c, Tabby and Tfm mice. The relative levels of Fas antigen mRNA are consistently higher in glands of males, whereas amounts of bcl-2 mRNA are greater in tissues of F1, C3H and BALB/c females. Testosterone administration induced a significant increase in the lacrimal gland content of Bax mRNA, but a striking decrease in the lacrimal tissue level of bcl-2 mRNA in F1 and C3H mice. Lacrimal glands of Tfm mice contained elevated amounts of bcl-2 mRNA, as compared to values in tissues of their Tabby controls. In summary, our findings show that fundamental gender-related differences exist in the expression of genes associated with programmed cell death in lacrimal glands of autoimmune and normal mice. In addition, some of these differences may be due, at least in part, to the effect of androgens. PMID: 10619357 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 520: Exp Mol Pathol. 1999 Dec;67(3):135-43. Comment in: Exp Mol Pathol. 1999 Dec;67(3):131-4. Fluorescence in situ hybridization analysis of HER-2/neu, c-myc, and p53 in endometrial cancer. Williams JA Jr, Wang ZR, Parrish RS, Hazlett LJ, Smith ST, Young SR. Department of Obstetrics and Gynecology, University of South Carolina School of Medicine, Columbia 29203, USA. Our objective was to evaluate the association between HER-2/neu, c-myc, p53, and clinicopathologic variables in endometrial cancer using fluorescence in situ hybridization (FISH) cytogenetic analysis. FISH analysis for HER-2/neu, c-myc, and p53 was performed on 47 endometrial cancer specimens. Amplification of HER-2/neu was seen in 4/47 (8.5%) cases and amplification of c-myc was seen in 7 of 47 (15%) cases; neither was associated with adverse clinicopathologic variables or survival. Deletion of p53 was seen in 31/47 (66%) cases and was associated with poor histologic grade (P = 0.008). There was no impact of genetic alterations on overall survival or disease-free interval. Grade 3 tumor was associated with poor overall survival (P = 0.032). This study found that p53 deletion is a common genetic alteration in endometrial cancer and is associated with poor-grade tumors. Copyright 1999 Academic Press. PMID: 10600396 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 521: Pathol Res Pract. 1999;195(11):765-72. Hepatic angiomyolipoma in a 26-year-old Caucasian woman with a history of tibial osteosarcoma. Rocken C, Schneider-Stock R, Buhtz P, Manger T, Roessner A. Institute of Pathology, Otto-von-Guericke-University, Magdeburg, Germany. christoph.roecken@medizin.uni-magdeburg.de We report on a 26-year-old Caucasian woman who was referred to the Department of Surgery complaining of general malaise, feeling of fullness with occasional vomiting and intermittent jaundice. The patient had previously suffered from tibial osteosarcoma of the left leg which was resected 13 years ago and subsequently treated with radiation and chemotherapy. During clinical investigations a 12 x 12 x 6.5 cm large mass was found in the left lobe of the liver. This was resected, and subsequently shown to be a sporadic hepatic angiomyolipoma. In order to investigate a possible link between the two tumours, we investigated mutations in the p53-gene, loss of heterozygosity (LOH) at p53, Rb and p16, c-Myc expression, and the telomerase activity of the angiomyolipoma and the osteosarcoma. Whilst the tibial osteosarcoma showed LOH at p16, no genetic alterations or increased telomerase activity were found in the angiomyolipoma. The occurrence of both these tumours in this patient is therefore probably a coincidence. Publication Types: Case Reports PMID: 10605697 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 522: Biochem Biophys Res Commun. 1999 Dec 20;266(2):472-80. Identification and characterization of genes whose expressions are altered in rat 6 fibroblasts transformed by mutant p53(val135). Yam JW, Zheng JY, Hsiao WL. Department of Biology and Department of Biochemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, People's Republic of China. The wild-type tumor suppressor gene p53 is known as a transcription factor in activating or suppressing target genes that encode proteins in regulating genome stability, DNA damage, cell arrest, and apoptosis. However, the role of mutant p53 in the process of cell transformation is still unclear. Our recent work indicated that overexpression of mutant p53(val135) induced high incidence of spontaneous transformation in prolonged cultures of Rat 6 fibroblasts. In order to identify genes related to neoplastic transformation induced by the mutant p53, the p53(val135)-overexpressor R6#13-8 and its derived spontaneously transformed cell line T2 were analyzed by mRNA differential display. In a systematic screening with 80 primer sets of RT-PCR reactions, three genes were found to be differentially expressed between R6#13-8 and T2 cells. Two genes, identified as homologues of the growth factor inducible immediate-early gene Cyr61 and the human nonmuscle myosin heavy chain-B, were down-regulated in T2 cells. Interestingly, both genes were also suppressed in Rat 6 cells transformed by c-H-ras and v-myc, but not by v-src genes. The third gene is a homologue of the frizzled related protein, a gene family that acts, in some cases, as an antagonist to the Wnt signaling pathway. It is intriguing that the rat homologue of the frizzled related protein was only expressed in p53(val135)-overexpressing cells, but not in the parental Rat 6 cells. However, the same gene was also highly expressed in ras-transformed Rat 6 cells, and moderately expressed in v-src-transformed Rat 6 cells. This is the first study in which the association of mutant p53 to these three genes is revealed. Our current report may provide new clues to the role of mutant p53 in the process of cell transformation. Copyright 1999 Academic Press. PMID: 10600527 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 523: Oncogene. 1999 Nov 25;18(50):7016-25. Induction of apoptosis in U937 human leukemia cells by suberoylanilide hydroxamic acid (SAHA) proceeds through pathways that are regulated by Bcl-2/Bcl-XL, c-Jun, and p21CIP1, but independent of p53. Vrana JA, Decker RH, Johnson CR, Wang Z, Jarvis WD, Richon VM, Ehinger M, Fisher PB, Grant S. Department of Medicine, Medical College of Virginia, Richmond 23298, USA. Determinants of differentiation and apoptosis in myelomonocytic leukemia cells (U937) exposed to the novel hybrid polar compound SAHA (suberoylanilide hydroxamic acid) have been examined. In contrast to hexamethylenbisacetamide (HMBA), SAHA-related maturation was limited and accompanied by marked cytoxicity. SAHA-mediated apoptosis occurred within the G0G1 and S phase populations, and was associated with decreased mitochondrial membrane potential, caspase-3 activation, PARP degradation, hypophosphorylation/cleavage of pRB, and down-regulation of c-Myc, c-Myb, and B-Myb. Enforced expression of Bcl-2 or Bcl-XL inhibited SAHA-induced apoptosis, but only modestly potentiated differentiation. While SAHA induced the cyclin-dependent kinase inhibitor p21CIP1, antisense ablation of this CDKI increased, rather than decreased, SAHA-related lethality. In contrast, conditional expression of wild-type p53 failed to modify SAHA actions, but markedly potentiated HMBA-induced apoptosis. Finally, SAHA modestly increased expression/activation of the stress-activated protein kinase (SAPK/JNK); moreover, SAHA-related lethality was partially attenuated by a dominant-negative c-Jun mutant protein (TAM67). SAHA did not stimulate mitogen-activated protein kinase (MAPK), nor was lethality diminished by the specific MEK/MAPK inhibitor PD98059. These findings indicate that SAHA potently induces apoptosis in human leukemia cells via a pathway that is p53-independent but at least partially regulated by Bcl-2/Bcl-XL, p21CIP1, and the c-Jun/AP-1 signaling cascade. PMID: 10597302 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 524: Cytometry. 1999 Feb 1;35(2):97-116. Cell cycle models for molecular biology and molecular oncology: exploring new dimensions. Shackney SE, Shankey TV. Department of Human Oncology and Human Genetics, Allegheny University of the Health Sciences, Pittsburgh, Pennsylvania 15212, USA. shackney@pgh.auhs.edu Some cell cycle models assume that cells are normally in a quiescent state until they are stimulated to enter the cell cycle and proceed through an S phase of fixed duration. Other models assume that cells normally cycle rapidly until they undergo growth retardation, proceed through an S phase of longer duration, and then undergo apoptosis or cell differentiation preferentially. These seemingly contradictory model types can be reconciled by restricting the latter type to the transition from log phase to plateau phase growth, and the former type to the recruitment of slowly proliferating cells into rapid cycle. Both proliferative states can be unified in a single cell cycle model that recognizes differences in the behavior of rapidly dividing and slowly dividing cells in the same population. Rb appears to play a major role in protecting slowly proliferating cells from apoptosis, permitting them to differentiate or persist as reserve cells that can be recruited into rapid cycle under appropriate circumstances. We examine the mechanistic basis for the recruitment phenomenon in some detail. The mitogenic signaling pathway is divided into a proximal segment, which consists of growth factor-induced membrane signaling, commonly through ras, raf, and cyclin D/cdk Rb kinase activation, and is subject to checks and balances that are designed to limit the propagation of the mitogenic signal. ras and raf compete with wild-type p53 both with respect to mitogenic signal propagation at the Rb node, and, separately, with respect to apoptosis/anti-apoptosis. The distal segment of the mitogenic signaling pathway, which consists of Rb phosphorylation, the release of E2F, the induction of c-myc, cyclins E and A, and DNA synthesis, is distinguished by a multiplicity of nested positive feedback loops; these would be expected to drive a mitogenic signal that entered the distal segment through at least one round of DNA synthesis. Using this model, we can identify two separate mechanistic strategies for neoplastic transformation. Chronic mitogenic stimulation of slowly proliferating cells would appear to be a common feature of Rb +/+ tumors. Rb -/- tumors dispense with the early segment of the mitogenic signaling pathway and its anti-apoptotic features, and maintain rapid cell cycling to compensate for high apoptotic rates. Publication Types: Review PMID: 10554165 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 525: Cancer Res. 1999 Nov 1;59(21):5586-95. The apoptotic effects and synergistic interaction of sodium butyrate and MG132 in human retinoblastoma Y79 cells. Giuliano M, Lauricella M, Calvaruso G, Carabillo M, Emanuele S, Vento R, Tesoriere G. Institute of Biological Chemistry, University of Palermo, Italy. This study deals with the apoptotic effect exerted on human retinoblastoma Y79 cells by both sodium butyrate and an inhibitor of 26S proteasome [z-Leu-Leu-Leu-CHO (MG132)] and their synergistic effect. Exposure to sodium butyrate (1-4 mM) induced an accumulation of cells in the G2-M phase that was already visible after 24 h of treatment, when morphological and biochemical signs of apoptosis appeared only in a small number of cells (5-10%). Thereafter, the apoptotic effects increased progressively with slow kinetics, reaching a maximum after 72 h of exposure, when they concerned a large fraction of cells (>75% with 4 mM sodium butyrate). Sodium butyrate stimulated the conversion of procaspase-3 into caspase-3 and also induced the cleavage of poly-(ADP-ribose) polymerase and lamin B, two hallmarks of apoptosis. All of the apoptotic signals were suppressed by benzyloxy carbonyl-Val-Ala-Asp-fluoromethylketone (a general inhibitor of caspase activities), whereas acetyl-Asp-Glu-Val-Asp aldehyde, a specific inhibitor of caspase-3 activity, only induced a partial reversion of the apoptotic effects. Sodium butyrate also decreased the Bcl-2 level, whereas it increased the Bax level and stimulated the release of cytochrome c from the mitochondria, an event that was most likely responsible for the activation of caspase-3. Finally, sodium butyrate activated 26S proteasome, the major extralysosomal degradative machinery, which is responsible for the degradation of short-lived proteins. Consequently, the levels of p53, N-myc, and IkappaBalpha (factors that play regulatory roles in apoptosis) diminished, whereas the nuclear level of nuclear factor kappaB concomitantly increased. Treatment of Y79 cells with MG132 induced apoptosis with more rapid kinetics than with sodium butyrate. The effects appeared after 8 h of incubation, reaching a maximum at 24 h, and they were accompanied by increased levels of N-myc, p53, and IkappaBalpha. MG132 also favored the release of cytochrome c from the mitochondria and increased the activity of caspase-3. When Y79 cells were exposed to combinations of sodium butyrate and MG132, the latter compound suppressed the decreasing effect induced by sodium butyrate on the levels of p53, N-myc, and IkappaBalpha and the increasing effect on the nuclear level of nuclear factor kappaB. Moreover, an increase in the level of Bax and an enhancement in the release of cytochrome c from the mitochondria were observed. Clear synergistic effects concerning the activation of both caspase-3 and apoptosis were induced by a combination of suboptimal doses of sodium butyrate and MG132. The results support the conclusion that MG132 potentiates the apoptotic effect of sodium butyrate by suppressing its stimulatory effect on 26S proteasome activity. Synergistic interactions between butyrate and inhibitors of proteasome could represent a new important tool in tumor therapy and, in particular, the treatment of retinoblastoma. PMID: 10554039 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 526: Jpn J Cancer Res. 1999 Oct;90(10):1109-16. Morphology, proliferation and apoptosis of mouse liver epithelial cells cultured as spheroids. Lee GH, Osanai M, Tokusashi Y. Department of Pathology, Asahikawa Medical College, Nishikagura. lee@host.or.jp The MLEC10 is an epithelial cell line derived from an untreated, normal C3H/HeN mouse liver. We previously demonstrated that tumorigenic variants from this cell line produced moderately differentiated hepatocellular carcinomas in nude mice. However, it has remained unclear whether the parental MLEC10 cells represent immortalized hepatocytes or so-called oval cells, both of which may serve as precursors for hepatocellular neoplasms. In this study, we performed 3-dimensional, spheroid culture of the MLEC100 cells in order to facilitate histological assessment of their lineage. Spheroidal aggregates were formalin-fixed and embedded in paraffin for routine light-microscopic observation of hematoxylin and eosin-stained sections. Histopathologically, the MLEC10 cells were indistinguishable from immature hepatocytes and distinct from oval cells. At the electron-microscopic level, their hepatocytic nature was evidenced by bile canaliculus structures and glycogen storage. Intriguingly, the spheroids contained fragmentary material reminiscent of Councilman bodies, implying apoptosis of the hepatocytes. Although the cells significantly proliferated during the first three days of culture, apoptotic death then resulted in a 75 % decrease in viable cell number. Thereafter, both apoptosis and cell division appeared silent, the numbers being unchanged. Expression of the p53 tumor suppressor gene became gradually elevated, correlating positively with growth arrest, but negatively with apoptosis, suggesting that the cell death occurred independently of p53. Our results indicate that at least some liver epithelial cell lines derived from untreated murine livers exhibit a hepatocytic morphology in spheroid culture. Also, the present culture system provides a useful tool for investigating biological phenomena, e.g. apoptosis, specifically involving liver cells, under 3-dimensional conditions. PMID: 10595740 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 527: J Immunol. 1999 Dec 15;163(12):6530-5. Increased p27Kip1 cyclin-dependent kinase inhibitor gene expression following anti-IgM treatment promotes apoptosis of WEHI 231 B cells. Wu M, Bellas RE, Shen J, Yang W, Sonenshein GE. Department of Biochemistry, Boston University Medical School, MA 02118, USA. Engagement of the B cell receptor of WEHI 231 immature B cells leads sequentially to a drop in c-Myc, to induction of the cyclin-dependent kinase inhibitor p27Kip1, and finally to apoptosis. Recently we demonstrated that the drop in c-Myc expression promotes cell death, whereas the induction of p27 has been shown to lead to growth arrest. In this paper, we demonstrate that increased p27 expression also promotes apoptosis of WEHI 231 B cells. The rescue of WEHI 231 cells by CD40 ligand engagement of its receptor prevented the increase in p27 induction. Inhibition of p27-ablated apoptosis induced upon expression of antisense c-myc RNA. Furthermore, specific induction of p27 gene expression resulted in apoptosis of WEHI 231 cells. Lastly, inhibition of expression of c-Myc, upon induction of an antisense c-myc RNA vector, was sufficient to induce increased p27 levels and apoptosis. Thus, these findings define a signaling pathway during B cell receptor engagement in which the drop in c-Myc levels leads to an increase in p27 levels that promotes apoptosis. PMID: 10586045 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 528: Int J Radiat Biol. 1999 Sep;75(9):1149-60. No association between radiosensitivity and TP53 status, G1 arrest or protein levels of p53, myc, ras or raf in human melanoma lines. Danielsen T, Smith-Sorensen B, Gronlund HA, Hvidsten M, Borresen-Dale AL, Rofstad EK. Department of Biophysics, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, Oslo. turidan@labmed.uio.no PURPOSE: First, to investigate whether TP53 status and/or radiation-induced G1 arrest are associated with radiosensitivity, and, second, to detect possible associations between protein levels of p53, myc, ras or raf and radiosensitivity and to investigate whether hypoxia-induced changes in the levels of these proteins are related to hypoxia-induced changes in radiosensitivity in human melanoma lines. MATERIALS AND METHODS: Radiosensitivity was assessed by clonogenic assays. TP53 status was investigated at the genomic level by constant denaturant gel electrophoresis and at the cDNA level by sequencing. G1 arrest was investigated by flow cytometric analysis of DNA. Protein expression of hypoxia-treated and untreated cells was assessed by flow cytometric measurements and Western blotting. RESULTS: Considerable differences in radiosensitivity were detected among melanoma lines with wild-type TP53. Only a fraction of the melanoma cells, differing between the lines, was arrested in G1. No association between the fraction of arrested cells and radiosensitivity was detected. Protein levels of p53, myc, ras or raf were not associated with radiosensitivity. Hypoxia-induced changes in p53, ras and raf levels were detected in all cell lines. Changes in the level of myc protein were detected for two of the four cell lines, while hypoxia-induced changes in radiosensitivity were observed only for one. CONCLUSIONS: Differences in radiosensitivity among melanoma lines cannot be elucidated by TP53 status, differences in G1 arrest or different levels of p53, myc, ras or raf proteins. Hypoxia-induced changes in p53, myc, ras or raf levels do not seem to be related to hypoxia-induced changes in radiosensitivity. PMID: 10528923 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 529: Leuk Res. 1999 Oct;23(10):939-46. Mutational analysis of transgenic mouse B cell lymphomas: indication of a Trp53-independent pathway in tumor progression. Samant SA, Sheppard RD. Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA. Deregulated myc, bcl-2 and/or TP53 gene expression is associated with non-Hodgkin's B cell lymphomas (B-NHLs). Emu-N-myc transgenic mice that misexpress N-myc protein and carry a non-disrupted bcl-2 gene develop indolent B cell lymphomas reminiscent of the B-NHL, follicular lymphoma. Tumors from mice with end-stage disease exhibited discrete, nodular lesions as well as areas of diffuse tumor likely due to coalescence of enlarged follicles. Tumor DNAs were screened for mutations in the Trp53 gene, the murine homologue of the TP53 gene, which participates in B cell differentiation and survival. By PCR-based sequence analyses, we determined there were no mutations in exons 5-8, the common sites of TP53 mutation in B-NHLs. These findings suggested that disease progression in our novel murine lymphoma model may proceed via a Trp53-independent pathogenetic pathway. PMID: 10573140 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 530: Int J Cancer. 1999 Dec 22;84(6):562-7. c-myc, p53 and bcl-2, apoptosis-related genes in infiltrating breast carcinomas: evidence of a link between bcl-2 protein over-expression and a lower risk of metastasis and death in operable patients. Le MG, Mathieu MC, Douc-Rasy S, Le Bihan ML, Adb El All H, Spielmann M, Riou G. Institut National de la Sante et de la Recherche Medicale (INSERM-U521), Institut Gustave Roussy, Villejuif, France. Apoptosis is an important physiological process controlled by multiple genes, including c-myc, p53 and bcl-2, and its inhibition may lead to the development of human cancers. In this study, we analyzed expression of the c-myc gene using Northern blot and of the p53 and bcl-2 proteins by immuno-histochemistry in 175 breast tumor specimens obtained from patients with operable breast cancer. We evaluated the relation between expression of these 3 genes and (i) the main usual prognostic factors (tumor size, histo-prognostic grade, hormone receptors and number of positive nodes); (ii) the risk of death and relapse, taking into account these 4 factors, after a mean period of follow-up of 9.5 years (SD 2 years). Over-expression of c-myc, p53 and bcl-2 was observed in 35%, 23% and 63% of tumors, respectively. Over-expression of c-myc was strongly linked to the number of positive nodes (p = 0.0005). p53 protein expression was associated with both high-grade (p = 0.0001) and hormone receptor-negative (p = 0.0001) tumors. In contrast, bcl-2 protein over-expression was associated with the main favorable prognostic factors and, more particularly, with hormone receptor-positive tumors (p = 0.0001). Multivariate analysis, using the Cox model, showed that only 2 factors were independently linked to the risk of death: number of positive nodes, which increased the risk (p = 0.0001), and bcl-2 protein over-expression, which decreased the risk (p = 0.008). When bcl-2 over-expression was studied in relation to nodal status, hormone receptor status and chemo- and hormone therapy, no significant difference was observed between different subgroups of patients. bcl-2 expression was also associated with a significantly lower risk of distant metastasis (p = 0.04). In conclusion, bcl-2 expression characterizes a particular phenotype of breast cancer with a favorable prognosis, and it may therefore be used as a marker of long-term survival. Int. J. Cancer (Pred. Oncol.) 84:562-567, 1999. Copyright 1999 Wiley-Liss, Inc. PMID: 10567899 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 531: Nat Cell Biol. 1999 May;1(1):20-6. Nucleolar Arf sequesters Mdm2 and activates p53. Weber JD, Taylor LJ, Roussel MF, Sherr CJ, Bar-Sagi D. Howard Hughes Medical Institute, St Jude's Children's Research Hospital, Memphis, Tennessee 38105, USA. The Ink4/Arf locus encodes two tumour-suppressor proteins, p16Ink4a and p19Arf, that govern the antiproliferative functions of the retinoblastoma and p53 proteins, respectively. Here we show that Arf binds to the product of the Mdm2 gene and sequesters it into the nucleolus, thereby preventing negative-feedback regulation of p53 by Mdm2 and leading to the activation of p53 in the nucleoplasm. Arf and Mdm2 co-localize in the nucleolus in response to activation of the oncoprotein Myc and as mouse fibroblasts undergo replicative senescence. These topological interactions of Arf and Mdm2 point towards a new mechanism for p53 activation. PMID: 10559859 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 532: Neuroreport. 1999 Sep 29;10(14):3087-91. Roles of p53, c-Myc, Bcl-2, Bax and caspases in serum deprivation-induced neuronal apoptosis: a possible neuroprotective mechanism of basic fibroblast growth factor. Liu X, Zhu XZ. Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai. Using flow cytometric analysis, we examined the temporal changes of p53, c-Myc, Bcl-2, Bax expression in rat primary cortex neurons after serum deprivation. Activities of caspase-1 and caspase-3 were also measured. Serum deprivation induced apoptosis accompanied by a rapid down-regulation of p53, Bcl-2 and an up-regulation of c-Myc, Bax and caspase-3 activity. Pretreatment with basic fibroblast growth factor prevented the apoptosis with an attenuation of the changes of p53, Bcl-2, Bax levels and caspase-3 activity but had no effect on the change of c-Myc level. These results suggest that serum deprivation induces apoptosis through a signaling pathway involving p53, Bcl-2, Bax, c-Myc and caspase-3. The effect of the basic fibroblast growth factor against apoptosis may result from its capability of blocking the apoptosis cascade. PMID: 10549828 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 533: Genes Dev. 1999 Oct 15;13(20):2670-7. INK4a/ARF mutations accelerate lymphomagenesis and promote chemoresistance by disabling p53. Schmitt CA, McCurrach ME, de Stanchina E, Wallace-Brodeur RR, Lowe SW. Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA. The INK4a/ARF locus encodes upstream regulators of the retinoblastoma and p53 tumor suppressor gene products. To compare the impact of these loci on tumor development and treatment response, the Emu-myc transgenic lymphoma model was used to generate genetically defined tumors with mutations in the INK4a/ARF, Rb, or p53 genes. Like p53 null lymphomas, INK4a/ARF null lymphomas formed rapidly, were highly invasive, displayed apoptotic defects, and were markedly resistant to chemotherapy in vitro and in vivo. Furthermore, INK4a/ARF(-/-) lymphomas displayed reduced p53 activity despite the presence of wild-type p53 genes. Consequently, INK4a/ARF and p53 mutations lead to aggressive tumors by disrupting overlapping tumor suppressor functions. These data have important implications for understanding the clinical behavior of human tumors. PMID: 10541553 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 534: Genes Dev. 1999 Oct 15;13(20):2658-69. Disruption of the ARF-Mdm2-p53 tumor suppressor pathway in Myc-induced lymphomagenesis. Eischen CM, Weber JD, Roussel MF, Sherr CJ, Cleveland JL. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. Transgenic mice expressing the c-Myc oncogene driven by the immunoglobulin heavy chain enhancer (Emu) develop B-cell lymphoma and exhibit a mean survival time of approximately 6 months. The protracted latent period before the onset of frank disease likely reflects the ability of c-Myc to induce a p53-dependent apoptotic program that initially protects animals against tumor formation but is disabled when overtly malignant cells emerge. In cultured primary mouse embryo fibroblasts, c-Myc activates the p19(ARF)-Mdm2-p53 tumor suppressor pathway, enhancing p53-dependent apoptosis but ultimately selecting for surviving immortalized cells that have sustained either p53 mutation or biallelic ARF deletion. Here we report that p53 and ARF also potentiate Myc-induced apoptosis in primary pre-B-cell cultures, and that spontaneous inactivation of the ARF-Mdm2-p53 pathway occurs frequently in tumors arising in Emu-myc transgenic mice. Many Emu-myc lymphomas sustained either p53 (28%) or ARF (24%) loss of function, whereas Mdm2 levels were elevated in others. Its overexpression in some tumors lacking p53 function raises the possibility that Mdm2 can contribute to lymphomagenesis by interacting with other targets. Emu-myc transgenic mice hemizygous for ARF displayed accelerated disease (11-week mean survival), and 80% of these tumors lost the wild-type ARF allele. All ARF-null Emu-myc mice died of lymphoma within a few weeks of birth. About half of the tumors arising in ARF hemizygous or ARF nullizygous Emu-myc transgenic mice also overexpressed Mdm2. Therefore, Myc activation strongly selects for spontaneous inactivation of the ARF-Mdm2-p53 pathway in vivo, cancelling its protective checkpoint function and accelerating progression to malignancy. PMID: 10541552 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 535: Genes Chromosomes Cancer. 1999 Dec;26(4):329-35. Isolation and characterization of a novel TP53-inducible gene, TP53TG3. Ng CC, Koyama K, Okamura S, Kondoh H, Takei Y, Nakamura Y. Division of Clinical Genetics, Department of Medical Genetics, Biomedical Research Center, Osaka University Medical School, Osaka, Japan. We applied the differential mRNA display method to isolate genes regulated by wild-type TP53 in cells of a colon-cancer line (SW480) in which we had established an inducible TP53 expression system under the control of the lactose operon. Here we report isolation and characterization of a novel TP53-inducible gene, termed TP53TG3 (TP53 target gene 3). Its DNA sequence was identical to sequences present in two BAC clones that had been mapped to chromosome band 16p13. The gene expressed several transcripts by alternative splicing; the two major transcripts, TP53TG3a and TP53TG3b, encoded 124- and 132-amino-acid peptides that were expressed predominantly in testis. Immunohistochemical analysis using cancer cells (HeLa or H1299) that had been transfected with plasmid DNA designed to express the MYC-fused TP53TG3 proteins indicated that these products were present mainly in the cytoplasm 20 hr after transfection. However, 40 hr after transfection, the recombinant proteins had accumulated in the nuclei of some cells. Because no known nuclear localization domain was present in the amino acid sequence, we suspect that this protein plays an important role in the TP53-mediated signaling pathway, when it forms complexes with other protein(s) and is transferred by them into the nucleus. Genes Chromosomes Cancer 26:329-335, 1999. Copyright 1999 Wiley-Liss, Inc. PMID: 10534768 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 536: Clin Ter. 1999 May-Jun;150(3):197-202. [IL-6, p53 and proto-oncogene c-myc play different roles as biological markers of plasma cell dyscrasias] [Article in Italian] Alvino S, Marcucci M, Canzoniere D, Mosiello A, Del Monte G, Venturo I, Rinaldi M, Gandolfo GM, Lopez M, Greco C. Servizio di Patologia Clinica, Istituto Regina Elena per lo Studio e la Cura dei Tumori, Roma, Italia. PURPOSE: To determine the role of serum levels of IL-6 and p53 mutant protein as well as of c-myc proto-oncogene alterations: a) in discriminating between benign (MGUS) and malignant Plasma cell dyscrasias (Multiple and Microsecreting Myeloma, Plasmocytoma); b) in monitoring the clinical course of malignant forms of this disease. PATIENTS AND METHODS: Eighty-eight patients affected by Plasma cell dyscrasias (58 MGUS, 24 MM and 6 PLC) entered this study. Using commercially available ELISA kits, serum levels of IL-6 and p53 have been determined in all the patients. In addition, a selected group of patients (n = 30) was also analyzed for structural c-myc gene alterations by Southern blot technique. RESULTS: The results show that, conversely from p53 protein, IL-6 and c-myc gene may represent useful diagnostic markers for discriminating benign from malignant forms of Plasma cell dyscrasia. On the contrary, preliminary findings of the same work indicate a potential role for the mutant p53 protein in monitoring the response to chemotherapy of patients affected by MM or PLM. CONCLUSIONS: Overall, these data suggest that the combined use of IL-6, p53 and c-myc may provide a new approach for a more rational management of Plasma cell dyscrasia patients. PMID: 10528431 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 537: J Cell Physiol. 1999 Dec;181(3):385-92. Emerging roles of BRCA1 in transcriptional regulation and DNA repair. Chen Y, Lee WH, Chew HK. Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78284, USA. BRCA1 was the first breast cancer susceptibility gene to be identified and cloned. In individuals from high-risk families, mutations in BRCA1 increase the lifetime risk of developing breast cancer eight to tenfold, compared to the general population. How the BRCA1 protein product normally functions to suppress tumor formation and how defects in the gene can ultimately lead to breast cancer have been the focus of intense scrutiny by the scientific and medical communities. BRCA1 has intrinsic transactivation activity and is able to activate the p21 promoter. In addition, BRCA1 is linked to a number of genes involved in transcriptional regulation, including CtIP, c-Myc, the RNA holoenzyme complex, and the histone deacetylase complex. Moreover, BRCA1 is essential for cellular response to DNA damage repair. Inactivation of Brca1 in mouse embryonic stem and fibroblast cells results in increased cell sensitivity to DNA-damaging agents. In human cells, BRCA1 binds to both Rad50 and Rad51 and colocalizes with these proteins at repair foci. Part of BRCA1's response to DNA damage may in fact be corroborated through transcriptional regulation. The expression of GADD45, a DNA damage-responsive gene, is increased immediately after induction of BRCA1. Recently, BRCA1 was shown to repress estradiol (E2)-responsive ER-alpha-mediated transcriptional activity, potentially linking the multiple functions of BRCA1 to specific tissue targets. These recent developments in BRCA1 function are an encouraging step toward understanding the role of BRCA1 in breast cancer formation. Copyright 1999 Wiley-Liss, Inc. Publication Types: Review Review, Tutorial PMID: 10528224 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 538: Clin Immunol. 1999 Nov;93(2):152-61. Curcumin causes the growth arrest and apoptosis of B cell lymphoma by downregulation of egr-1, c-myc, bcl-XL, NF-kappa B, and p53. Han SS, Chung ST, Robertson DA, Ranjan D, Bondada S. Department of Microbiology and Immunology, Department of General Surgery, Lexington, Kentucky 40536, USA. It has been well known that curcumin is a powerful inhibitor of proliferation of several tumor cells. However, the molecular basis of the anti-proliferative effect of curcumin has not been investigated in detail. In this paper, we present evidence to show that curcumin inhibited proliferation of a variety of B lymphoma cells. At low concentrations curcumin inhibited the proliferation of BKS-2, an immature B cell lymphoma, more effectively than that of normal B lymphocytes and caused the apoptosis of BKS-2 cells in a dose- and time-dependent manner. Furthermore, curcumin downregulated the expression of survival genes egr-1, c-myc, and bcl-X(L) as well as the tumor suppressor gene p53 in B cells. In addition, NF-kappaB binding activity was also downregulated almost completely by curcumin. Stimulation with CpG oligonucleotides or anti-CD40 overcame growth inhibition induced by low concentrations of curcumin. Our results suggest that curcumin caused the growth arrest and apoptosis of BKS-2 immature B cell lymphoma by downregulation of growth and survival promoting genes. Copyright 1999 Academic Press. PMID: 10527691 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 539: Brain Res Mol Brain Res. 1999 Aug 25;71(2):210-6. Roles of p53, c-Myc, Bcl-2, Bax and caspases in glutamate-induced neuronal apoptosis and the possible neuroprotective mechanism of basic fibroblast growth factor. Liu X, Zhu XZ. Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. By using flow-cytometric analysis, we examined the involvement of p53, c-Myc, Bcl-2 and Bax in the glutamate-induced cell death in cultured cortical neurons. The activities of caspase-1-like and caspase-3-like proteases were also measured after the glutamate treatment. The apoptosis rate of the cells increased after 12 h and 24 h treatment with glutamate. The temporal profile of p53, c-Myc, Bcl-2, Bax expression and caspases activation after glutamate treatment suggest that Bcl-2, c-Myc and caspase-3 play important roles in the excitotoxic neuronal cell death. The down-regulation of Bcl-2 may be an important early stage event, which may cause the activation of caspase-3. c-Myc is also involved in the process of apoptosis though its precise role remains elusive. bFGF exhibited the capability to antagonize the neuronal apoptosis caused by glutamate. The antiapoptotic potential of bFGF may result from its attenuating effect on the down-regulation of Bcl-2 induced by glutamate and, subsequently, blockade of apoptosis cascade. This may provide a possible explanation for its neuroprotective effect against ischemic cell death. PMID: 10521575 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 540: Br J Haematol. 1999 Oct;107(1):106-13. Molecular features of primary mediastinal B-cell lymphoma: involvement of p16INK4A, p53 and c-myc. Scarpa A, Moore PS, Rigaud G, Inghirami G, Montresor M, Menegazzi M, Todeschini G, Menestrina F. Dipartimento di Patologia, Sezione Anatomia Patologica, Universita di Verona, Italy. scarpa@anpat.univr.it Primary mediastinal B-cell lymphoma (PMBL) shows chromosome 9p anomalies in 50% of cases. Based on reports that p16INK4A gene, located on this chromosomal arm, is frequently altered in aggressive lymphomas, we analysed for alterations of this gene in 27 cases of PMBL, which were part of a series of 32 PMBL cases that have been characterized for alterations in c-myc, p53, N-ras, bcl-1, bcl-2, bcl-6 and for Epstein-Barr virus (EBV) infection. Four cases showed p16INK4A gene anomalies, including three with promoter methylation and one homozygous deletion. Eight PMBLs showed c-myc rearrangements. Three additional cases showed sequence variations in the c-myc P2 promoter, two of which consisted of the same germline variation involving a novel polymorphic XhoI site. Four tumours contained p53 gene mutations and three had clonal EBV infection. One case had a bcl-6 rearrangement. In conclusion, our study shows that p16INK4, c-myc and p53 alterations occur in 15%, 25% and 13% of PMBLs, respectively. EBV monoclonality was found in 9% of cases, whereas no abnormality was detected in bcl-1, bcl-2 and N-ras. Thus, none of the common genetic aberrations seen in other types of non-Hodgkin's lymphomas appears to be stringently involved in the pathogenesis of this unique lymphoma type. PMID: 10520030 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 541: Cancer Res. 1999 Oct 1;59(19):5017-22. Paradoxical inhibition of c-myc-induced carcinogenesis by Bcl-2 in transgenic mice. de La Coste A, Mignon A, Fabre M, Gilbert E, Porteu A, Van Dyke T, Kahn A, Perret C. Institut National de la Sante et de la Recherche, U129, ICGM, Universite Paris V Rene Descartes, France. Here, we investigated changes in apoptosis during tumor progression by analyzing the effect of coexpressing various antiapoptotic genes on the multistage process of c-myc-induced hepatocarcinogenesis in transgenic mice. Whereas continuous c-myc gene overexpression in the liver led to cellular hepatocarcinoma, the coexpression of the bcl-2 gene inhibited the emergence of liver tumors, by inhibiting a pretumoral phase characterized by increased proliferation and apoptosis. This antioncogenic effect was specific to Bcl-2 and was not shared by other antiapoptotic genes such as bcl-xL and a dominant negative form of p53. Thus, we have shown that Bcl-2 can have a tumor suppressor effect in vivo on c-myc-induced hepatocarcinogenesis during the emergence of neoplastic foci. PMID: 10519417 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 542: Leukemia. 1999 Oct;13(10):1554-63. Apoptosis in patients with myelodysplastic syndromes: differential involvement of marrow cells in 'good' versus 'poor' prognosis patients and correlation with apoptosis-related genes. Tsoplou P, Kouraklis-Symeonidis A, Thanopoulou E, Zikos P, Orphanos V, Zoumbos NC. Hematology Division, Dept of Internal Medicine, Patras University, Medical School, Patras 261 10, Greece. Apoptosis has been implicated in the pathogenesis of marrow failure in MDS and the coexistence of marrow hypercellularity along with blood cytopenias was seen as evidence of extreme cell death of mainly mature cells in the marrow (ineffective hematopoiesis). We investigated apoptosis in 53 patients with MDS, by using single-step DNA extraction and gel electrophoresis and then by separating fresh marrow mononuclear cells in CD34+ and CD34- populations and in situ single cell evaluation of the process. We also studied the expression of apoptosis-related genes, in total and separated mononuclear marrow cells and correlated the findings with clinical and laboratory characteristics. Patients with apoptosis had increased marrow cellularity, longer overall survival and a longer period for transformation to AML. In 'good' prognosis MDS patients, total mononuclear marrow cells, as well as isolated populations of CD34+ and CD34- cells showed significant degrees of apoptosis; in 'poor' prognosis cases, however, apoptosis was evident only in a large percentage of CD34+ marrow cells and not in total or CD34- cells. Absence of expression of both c-myc and p53 in total marrow cells was associated with significant degrees of apoptosis and in isolated CD34+ and CD34- marrow cells the phenomenon was inversely correlated with the level of bcl-2 expression. In conclusion, marrow apoptosis is detected in both CD34+ and CD34- cells in early MDS and seems to be restricted to CD34+ cells in advanced MDS cases. PMID: 10516757 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 543: Pathol Int. 1999 Jul;49(7):648-52. Molecular cytogenetic identification of cyclin D1 gene amplification in a renal pelvic tumor attributed to phenacetin abuse. Lee CC, Wanibuchi H, Yamamoto S, Hirose M, Hayashi Y, Fukushima S. First Department of Pathology, Osaka City University Medical School, Nagoya, Japan. Despite extensive epidemiologic evidence of phenacetin abuse as a risk factor for renal pelvic carcinomas, genetic alterations in the resultant tumors remain largely unclear. In this report, a phenacetin-associated renal pelvic carcinoma (histologically a transitional-cell carcinoma) from an 80-year-old female patient was evaluated by molecular cytogenetic methods. Fluorescence in situ hybridization was used to identify chromosome gains or losses for the cyclin D1, p53, Rb and c-myc genes and the ploidy of their respective chromosomes. Cyclin D1 gene amplification, but normal copy numbers of p53, Rb and c-myc, and normal ploidy of chromosomes 8, 11, 13 and 17 were observed. Expression of cyclin D1 protein was confirmed by immunohistochemistry. In the absence of p53, Rb or c-myc abnormalities, the results suggested that cyclin D1 gene amplification and its protein overexpression may be involved in the genesis of renal pelvic carcinomas associated with phenacetin abuse. Publication Types: Case Reports PMID: 10504527 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 544: Int J Cancer. 1999 Oct 22;84(5):516-20. Genetic changes associated with telomerase activity in breast cancer. Loveday RL, Greenman J, Drew PJ, Monson JR, Kerin MJ. Academic Surgical Unit, Castle Hill Hospital, Hull, UK. Telomerase, the enzyme responsible for maintenance of the telomeres, is absent from the vast majority of somatic cells but is present in most tumours. Little is known about how telomerase is activated in cancer, although it is thought vital for immortalisation to occur. The aim of our study was to identify genetic changes associated with telomerase activity. Thirty-three breast carcinomas were assessed for telomerase activity using the PCR based TRAP assay, and genetic changes by comparative genomic hybridisation (CGH). Seventy-five percent of the tumours were telomerase positive, and these were further divided into low or high level telomerase activity groups. A large number of genetic aberrations were identified but 4 chromosomal regions were identified that correlated with the telomerase status of the tumour. Gain of 1q correlated with telomerase negative tumours, gain of 3q correlated with high level telomerase activity. Gain of 8q correlated with telomerase positive tumours and furthermore with high level telomerase activity; deletion of 17p also correlated with high level telomerase activity. CGH analysis of breast tumours in conjunction with telomerase status has supported early results suggesting the involvement of the telomerase hTR, c-myc and p53 genes in the control of telomerase activity. These genes are located on chromosomes 3q, 8q and 17p. Most importantly, our results have identified the involvement of gene(s) located on chromosome 1q in telomerase expression. Copyright 1999 Wiley-Liss, Inc. PMID: 10502730 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 545: Oncogene. 1999 Sep 23;18(39):5464-72. Adenovirus-mediated transfer of wild-type p53 gene sensitizes TNF resistant MCF7 derivatives to the cytotoxic effect of this cytokine: relationship with c-myc and Rb. Ameyar M, Shatrov V, Bouquet C, Capoulade C, Cai Z, Stancou R, Badie C, Haddada H, Chouaib S. INSERM U487 'Cytokines et Immunologie des Tumeurs Humaines', Institut Gustave Roussy, 94805 Villejuif, France. Tumor suppressor p53 is a nuclear transcription factor that blocks cell cycle progression and induces apoptosis. We have previously shown that the MCF7 resistance to the cytotoxic action of TNF correlates with p53 mutations. In the present study, we used a recombinant adenovirus carrying a wild-type p53 gene (Adwtp53) in order to investigate the effect of wt p53 transfer on modulation of cell resistance to the cytotoxic action of TNF. Our data indicate that infection of TNF resistant MCF7 cells (1001 and MCF7/Adr) with Adwtp53 resulted in the restoration of wt p53 expression and function as respectively revealed by the yeast assay and the induction of p53 inducible genes MDM2 and p21. Furthermore, the restoration of p53 function significantly sensitized TNF resistant cells to TNF cytotoxic action. This correlated with a significant down-regulation of c-myc in both TNF-resistant cell lines and a decrease of Retinoblastoma protein (Rb) in 1001 clone. In contrast, the effect of p53 seems to be independent from Bcl-2 and Bax protein level regulation. The present study suggests that the combination of TNF and Adwtp53 may be a potential strategy to sensitize mutant p53 TNF-resistant tumors to the cytotoxic action of this cytokine. PMID: 10498900 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 546: Genes Dev. 1999 Sep 1;13(17):2207-17. Twist is a potential oncogene that inhibits apoptosis. Maestro R, Dei Tos AP, Hamamori Y, Krasnokutsky S, Sartorelli V, Kedes L, Doglioni C, Beach DH, Hannon GJ. Experimental Oncology 1, Centro di Riferimento Oncologico, 33081 Aviano, Italy. Oncogene activation increases susceptibility to apoptosis. Thus, tumorigenesis must depend, in part, on compensating mutations that protect from programmed cell death. A functional screen for cDNAs that could counteract the proapoptotic effects of the myc oncogene identified two related bHLH family members, Twist and Dermo1. Both of these proteins inhibited oncogene- and p53-dependent cell death. Twist expression bypassed p53-induced growth arrest. These effects correlated with an ability of Twist to interfere with activation of a p53-dependent reporter and to impair induction of p53 target genes in response to DNA damage. An underlying explanation for this observation may be provided by the ability of Twist to reduce expression of the ARF tumor suppressor. Thus, Twist may affect p53 indirectly through modulation of the ARF/MDM2/p53 pathway. Consistent with a role as a potential oncoprotein, Twist expression promoted colony formation of E1A/ras-transformed mouse embryo fibroblasts (MEFs) in soft agar. Furthermore, Twist was inappropriately expressed in 50% of rhabdomyosarcomas, a tumor that arises from skeletal muscle precursors that fail to differentiate. Twist is known to block myogenic differentiation. Thus, Twist may play multiple roles in the formation of rhabdomyosarcomas, halting terminal differentiation, inhibiting apoptosis, and interfering with the p53 tumor-suppressor pathway. PMID: 10485844 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 547: Clin Endocrinol (Oxf). 1999 Jul;51(1):1-9. Apoptosis in neuroendocrine tumours. Wang DG. Center for Molecular Medicine, School of Medicine, University of Connecticut Health Center, Farmington CT 06030-3101, USA. dwang@nso2.uchc.edu Acquired resistance to apoptosis in neuroendocrine tumours (NETs) may promote clonal expansion and enhance the likelihood that subsequent mutations lead to growth or persistence of the neoplastic clone. Recent studies have demonstrated that deregulation of programmed cell death may be a critical component in multistep tumourigenesis of NETs and that the frequent expression of the Bcl-2 oncoprotein in these tumours may contribute to their pathogenesis. The genetic complementation of simultaneously deregulated Bcl-2 and c-Myc may be implicated in the multistep tumourigenesis of human NETs. Furthermore, because the efficacy of cytotoxic chemotherapy relies on its ability to induce programmed cell death, resistance to apoptosis typically correlates with chemoresistance, a phenomenon that is typical in NETs. Consideration of how oncogenes affect rates of cell death, in addition to augmenting growth, has already provided valuable insights into the biology of cancer. Understanding the molecular and cellular features of this process may enable the development and application of more effective and potentially curative treatment strategies in which the induction of programmed cell death is an integral component. Publication Types: Review PMID: 10468958 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 548: Immunology. 1999 Sep;98(1):47-54. Activation sensitizes human memory B cells to B-cell receptor-induced apoptosis. Berard M, Casamayor-Palleja M, Billian G, Bella C, Mondiere P, Defrance T. INSERM U 404 'Immunite et Vaccination', Avenue Tony Garnier, Lyon, France. The outcome of antigen receptor (B-cell receptor; BCR) ligation on B-cell survival can be influenced by multiple parameters. They are linked to the physical properties of the antigen itself, the maturational stage of the cells and the costimuli provided by different components of the innate and acquired immunity. Here we report that apoptosis prevails over stimulation when a BCR agonist is applied to human memory B cells which have been preactivated by CD40 ligand or anti-immunoglobulin antibodies. The susceptibility of activated memory B cells to BCR-induced killing is correlated with their enhanced expression of the transcripts encoding the pro-apoptotic molecules Bax, c-Myc and p53. The BCR-mediated apoptosis of activated memory B cells does not require extensive cross-linking of the antigen receptors and relies neither on engagement of the FcgammaRII nor on the Fas/Fas ligand (Fas-L) system. Our findings suggest that activation stimuli open the BCR-induced apoptotic pathway in memory B cells. Therefore we propose that the concept of activation-induced cell death (AICD), originally described for T cells, also applies to mature B lymphocytes. The functions fulfilled by the AICD of mature B cells in the regulation of B-cell responses are discussed. PMID: 10469233 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 549: Oncology. 1999;57(2):157-63. Amplification of c-myc in hepatocellular carcinoma: correlation with clinicopathologic features, proliferative activity and p53 overexpression. Kawate S, Fukusato T, Ohwada S, Watanuki A, Morishita Y. Second Department of Surgery, Gunma University School of Medicine, Gunma, Japan. Expression of the proto-oncogene c-myc has been implicated in liver regeneration and hepatocarcinogenesis. The biologic significance of c-myc gene amplification in human hepatocellular carcinoma, however, is unconfirmed. We correlated c-myc gene amplification with clinicopathologic features, proliferative activity, and p53 expression in 42 resected tumors. c-myc amplification in tumor tissue was determined using a differential polymerase chain reaction, a useful procedure for the evaluation of gene amplification in archival formalin-fixed paraffin-embedded tissues, in comparison with a dopamine D2 receptor gene. Proliferative activity was estimated by numbers of argyrophilic nucleolar organizer regions and immunohistochemical nuclear labeling rates using a monoclonal antibody against Ki-67. The c-myc gene was amplified in 14 of 42 tumors (33.3%). Amplification of c-myc was more frequent in younger patients and in larger tumors, and less differentiated tumors. No correlation was noted with alpha-fetoprotein level or viral hepatitis state. The amplification showed positive correlation with both proliferative activity and p53 overexpression. Disease-free survival in patients showing c-myc amplification was significantly shorter than in those without amplification. These results suggest that c-myc amplification is an indicator of malignant potential and poor prognosis in hepatocellular carcinoma. c-myc amplification and p53 alteration may be coparticipating events in the progression of these tumors. PMID: 10461064 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 550: Infect Immun. 1999 Sep;67(9):4794-800. Porin from Pseudomonas aeruginosa induces apoptosis in an epithelial cell line derived from rat seminal vesicles. Buommino E, Morelli F, Metafora S, Rossano F, Perfetto B, Baroni A, Tufano MA. CNR International Institute of Genetics and Biophysics, Area di Ricerca del C.N.R., Medical School, 2nd University of Naples, Italy. Micromolar concentrations of porin, purified from the outer membranes of Pseudomonas aeruginosa, induced in vitro the classic morphological and biochemical signs of apoptosis in an epithelial cell line (SVC1) derived from the rat seminal vesicle secretory epithelium. The programmed cell death (PCD) was p53 independent and associated with significant decrease of bcl-2 expression, a marked increase of c-myc transcriptional activity, and an absence of the mRNA coding for tissue transglutaminase. The Ca(2+) influx, caused by the porin treatment of SVC1 cells, appears to play an important role in the triggering of apoptosis in our biological model. The possibility that the porin property of inducing PCD plays a role in the infertility of individuals chronically infected by gram-negative bacteria is discussed. PMID: 10456933 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 551: Braz J Med Biol Res. 1999 Jul;32(7):897-904. Genetic alterations in head and neck squamous cell carcinomas. Nagai MA. Departamento de Radiologia, Faculdade de Medicina, Universidade de Sao Paulo, Brasil. nagai@usp.br The genetic alterations observed in head and neck cancer are mainly due to oncogene activation (gain of function mutations) and tumor suppressor gene inactivation (loss of function mutations), leading to deregulation of cell proliferation and death. These genetic alterations include gene amplification and overexpression of oncogenes such as myc, erbB-2, EGFR and cyclinD1 and mutations, deletions and hypermethylation leading to p16 and TP53 tumor suppressor gene inactivation. In addition, loss of heterozygosity in several chromosomal regions is frequently observed, suggesting that other tumor suppressor genes not yet identified could be involved in the tumorigenic process of head and neck cancers. The exact temporal sequence of the genetic alterations during head and neck squamous cell carcinoma (HNSCC) development and progression has not yet been defined and their diagnostic or prognostic significance is controversial. Advances in the understanding of the molecular basis of head and neck cancer should help in the identification of new markers that could be used for the diagnosis, prognosis and treatment of the disease. Publication Types: Review Review, Tutorial PMID: 10454750 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 552: Mol Carcinog. 1999 Aug;25(4):273-84. Dysregulation of apoptosis by c-myc in transgenic hepatocytes and effects of growth factors and nongenotoxic carcinogens. Christensen JG, Goldsworthy TL, Cattley RC. Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709, USA. Regulation of apoptosis is an important component of multistage hepatocarcinogenesis. The proto-oncogene c-myc has been shown to be important in apoptosis regulation and to be amplified and overexpressed in human and rodent liver neoplasia. The objectives of the study reported here were to determine whether apoptosis regulation is altered in transgenic hepatocytes that overexpress c-myc and whether growth factors or nongenotoxic carcinogens alter apoptosis regulation in c-myc versus wild-type hepatocytes. Hepatocytes isolated from c-myc transgenic mice had four fold more c-myc RNA and protein (at 12-48 h) in addition to increased apoptosis levels compared with wild-type hepatocytes. The increased apoptosis in c-myc hepatocytes was accompanied by increased p53, bax, and bak and decreased bcl-2 protein levels. Hepatocytes overexpressing c-myc were more sensitive to apoptosis induced by bleomycin but less sensitive to apoptosis induced by transforming growth factor (TGF)-beta. Phenobarbital, a potent liver tumor promoter, inhibited apoptosis in c-myc hepatocytes but not in wild-type hepatocytes, decreased p53 and bax, and increased bcl-2 protein levels. Nafenopin inhibited apoptosis in both c-myc and wild-type hepatocytes, whereas 2,3,7,8-tetrachlorodibenzo-pdioxin did not inhibit apoptosis in either wild-type or c-myc hepatocytes. TGF-alpha inhibited apoptosis and increased bcl-X(L) and decreased bak protein levels in c-myc hepatocytes but not in wild-type hepatocytes. Insulin-like growth factor-II did not affect apoptosis in c-myc or wild-type hepatocytes. In this study, overexpression of c-myc altered the response to apoptotic stimuli in transgenic hepatocytes. Furthermore, phenobarbital and TGF-alpha inhibited c-myc-induced apoptosis, which may have resulted in a selective growth advantage for an initiated cell population and which may be a mechanism for tumor promotion. PMID: 10449034 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 553: Mol Carcinog. 1999 Aug;25(4):256-61. Correlation of poly(ADP-ribose)polymerase and p53 expression levels in high-grade lymphomas. Menegazzi M, Scarpa A, Carcereri de Prati A, Menestrina F, Suzuki H. Dipartimento di Scienze Neurologiche e della Visione--Sezione Chimica Biologica, Universita di Verona, Italy. The steady-state levels of mRNA for the poly(ADP-ribose)polymerase (PARP), c-myc, p53, and histone H3 genes were investigated in 31 high-grade B-cell lymphomas by northern blot analysis. The panel included 15 nodal large B-cell lymphomas, nine mediastinal large B-cell lymphomas, and seven sporadic Burkitt's lymphomas. The PARP mRNA level was significantly higher in lymphomas than in control tissues and corresponded with the amount of PARP protein, as assessed by immunoblot analysis in six samples. The level of PARP mRNA was positively correlated with that of p53 mRNA. No correlation was found between the mRNA expression levels of PARP and histone H3, suggesting that PARP expression levels are independent of the proliferation rate of neoplastic cells. In this setting, the strong correlation between PARP and p53 suggests that the high expression of PARP may be associated with ongoing DNA damage in high-grade lymphomas. PMID: 10449032 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 554: J Virol. 1999 Sep;73(9):7882-5. Middle T antigen activation of signal transduction pathways does not overcome p53-mediated growth arrest. Doherty J, Freund R. Molecular and Cell Biology Program, University of Maryland, Baltimore, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA. Polyomavirus middle T antigen does not overcome p53-mediated G(1) arrest in mouse embryo fibroblasts. Middle T antigen still associates with the signaling molecules phosphatidylinositol 3-kinase and SHC and activates the transcriptional activity of c-Myc and AP1 in p53-arrested cells. Examination of cell cycle regulatory proteins indicated that p53 does not interfere with these mitogenic signals but acts later in the G(1) phase of the cell cycle. PMID: 10438885 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 555: Oncogene. 1999 Jul 22;18(29):4171-81. Promoter specificity and stability control of the p53-related protein p73. Lee CW, La Thangue NB. Division of Biochemistry and Molecular Biology, University of Glasgow, UK. The p53 family of proteins play instrumental roles in mediating the cellular response to stress. The p53-related gene product, p73, occurs as two distinct protein isoforms, referred to as alpha and beta, which differ in the length of the C-terminal region and arise through alternative splicing of the p73 RNA. Here, we describe an analysis of the transcription properties of p73 and show that although there are certain similarities between transcriptional activation mediated by p73 and p53, such as in their sensitivity to adenovirus E1A and the requirement for p300/CBP co-activator proteins, significant differences are apparent in the response mechanisms. Thus, we find that p73 shows a degree of specificity for the promoters of target genes that is quantitatively distinct from the response mediated by p53. For example, p73 activates the GADD45 gene more efficiently than p53, whereas the reverse situation was apparent for the p21 gene. These effects are, in part, due to the influence of a regulatory domain present in the extended C-terminal of the alpha isoform. Moreover, we provide evidence that this domain regulates protein abundance by influencing the proteasome-dependent degradation of p73. These data define a novel level of isoform-specific control in regulating p73 activity, and thereby highlight a significant difference between the mechanisms that govern the transcriptional activity of p53 and p73. PMID: 10435630 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 556: Oncogene. 1999 Jul 15;18(28):4091-8. Signaling through the antigen receptor of B lymphocytes activates a p53-independent pathway of c-Myc-induced apoptosis. Hagiyama H, Adachi T, Yoshida T, Nomura T, Miyasaka N, Honjo T, Tsubata T. Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Japan. Deregulated expression of c-Myc has been shown to induce or enhance apoptosis in various different cell types. c-Myc requires p53 for apoptosis in some but not all the cell types, indicating heterogeneous mechanisms for c-Myc-induced apoptosis. In B lymphoma line WEHI-231, stable expression of c-Myc has been demonstrated to protect cells from BCR-mediated apoptosis. However, stable expression of c-Myc carrying pro-apoptotic functions may generate variant cells resistant to apoptosis. By utilizing an inducible system for c-Myc, we demonstrated here that deregulated expression of c-Myc induced apoptosis of WEHI-231 by itself, indicating that c-Myc induces apoptosis in WEHI-231 as is the case for other cell types. When transactivation of p53 was inactivated, WEHI-231 cells overexpressing c-Myc no longer underwent apoptosis in the absence of other stimuli, but showed markedly enhanced apoptosis in the presence of BCR ligation. These results indicate that deregulated c-Myc expression enhances apoptosis by a p53-independent pathway in the presence of BCR signaling but requires p53 for apoptosis in the absence of BCR crosslinking in WEHI-231. BCR ligation may thus activate a p53-independent pathway of c-Myc-induced apoptosis. PMID: 10435590 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 557: J Oral Pathol Med. 1999 Jul;28(6):252-8. Potentially malignant and malignant lesions of the lip. Role of silver staining nucleolar organizer regions, proliferating cell nuclear antigen, p53, and c-myc in differentiation and prognosis. de Rosa I, Staibano S, Lo Muzio L, Delfino M, Lucariello A, Coppola A, De Rosa G, Scully C. Department of Biomorphological and Functional Sciences, University Federico II, Naples, Italy. The cellular changes leading to carcinoma of the lip are still not completely understood. This study was carried out on 44 malignant and potentially malignant lesions of the lower lip [30 squamous cell carcinomas (SCC), 7 actinic cheilitis, 3 leukoplakias, and 4 nodal metastases from lower lip SCC]. Silver-stained nucleolar organizer regions (AgNORs) and the immunohistochemical expression of proliferating cell nuclear antigen (PCNA), p53, and c-myc were evaluated on formalin-fixed, paraffin-embedded sections. The results indicate that the size and numbers of AgNORs and the percentage of PCNA-positive cells are sensitive parameters for discriminating between potentially malignant lesions and SCC, and for the prognostic sub-typing of lower lip SCC. Furthermore, while p53 positivity was found more frequently in high-grade carcinomas, p53-positive cellular clones were also found in some potentially malignant lesions, a finding probably related to ultraviolet-related cellular damage. These p53-positive lesions could be considered at higher risk of progression to malignancy than the p53-negative ones, although there is no evidence for this as yet. c-myc positivity was found only in some high-grade carcinomas and metastases, and appeared correlated with the later phases of lip carcinogenesis. The combined evaluation of the proliferation status, together with the changes in p53 and c-myc oncoproteins, might constitute useful markers for the prognostic evaluation of potentially malignant, as well as malignant, lesions of the lip. PMID: 10426197 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 558: J Biochem (Tokyo). 1999 Aug;126(2):340-6. Phorbol ester facilitates apoptosis in murine fibroblasts pretreated by mild ultraviolet radiation. Kimura H, Minakami H, Sekiguchi I, Otsuki K, Shoji A. Department of Biological Sciences, Faculty of Engineering, Gunma University, Kiryu, Gunma, 376-8515, Japan. Although phorbol 12-myristate 13-acetate (PMA) inhibits apoptosis and promotes the growth of some types of cells, it induces apoptosis in other cells. We evaluated the apoptotic effects of PMA on murine fibroblasts (L-929) that had been exposed to ultraviolet-B (UV-B) radiation at 312 nm, which promotes tumor cell growth. Exposure to PMA alone did not induce Fas, Fas-L, or apoptosis. Cells exposed to mild UV-B irradiation (80 J/m(2)) alone exhibited a slight expression of Fas and Fas-L 36 to 48 h after the exposure, and exhibited apoptosis as evidenced by DNA fragmentation 72 h after exposure. The addition of PMA (0.8 x 10(-5) to 3.2 x 10(-5) M) to the medium 24 h after the UV-B exposure markedly and dose-dependently enhanced these cell responses. Confluent untreated cells, cells cocultured with PMA, and cells cocultured with PMA for 24 h after the UV-B exposure consistently expressed mRNAs for wild-type p53, bcl-2, and ICE. Expression of c-myc mRNA was initially observed, but became undetectable in the cells cocultured for 24 h with a high concentration of PMA (3.2 x 10(-5) M) following UV-B exposure. Such cells subsequently exhibited the maximal apoptotic response. We conclude that mild exposure to UV-B altered murine fibroblast cells in such a way as to facilitate their death by apoptosis upon addition of PMA. PMID: 10423527 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 559: Mol Hum Reprod. 1999 Aug;5(8):737-41. Oncogenes and tumour suppressor genes in first trimester human fetal gonadal development. Quenby SM, Gazvani MR, Brazeau C, Neilson J, Lewis-Jones DI, Vince G. Division of Obstetrics and Gynaecology, City Hospital, Hucknall Road, Nottingham, NG5 1PB, UK. Tumour suppressor genes and oncogenes that control proliferation and apoptosis are known to play an important role in embryogenesis, second trimester fetal oocyte loss, adult ovulation, and in adult male testicular degeneration. We have examined tumour suppressor genes, oncogenes and oestrogen receptors during first trimester human gonadal differentiation to investigate their role at this crucial phase in development. Immunohistochemistry was used to localize the gene products of Bcl-2, c-erB-2, c-myc, p53, nm23 and oestrogen receptor. As gonadal development occurred at 6-12 weeks gestation, a changing pattern of expression was observed that varied in different cell types. The oestrogen receptor was not present in oogonia, spermatogonia and supporting cells during the first trimester. This study highlights the importance of oncogenes and tumour suppressor genes in first trimester gonadal development. PMID: 10421801 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 560: Mol Cell Biol. 1999 Aug;19(8):5339-51. c-Myc overexpression uncouples DNA replication from mitosis. Li Q, Dang CV. Program in Cellular and Molecular Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. c-myc has been shown to regulate G(1)/S transition, but a role for c-myc in other phases of the cell cycle has not been identified. Exposure of cells to colcemid activates the mitotic spindle checkpoint and arrests cells transiently in metaphase. After prolonged colcemid exposure, the cells withdraw from mitosis and enter a G(1)-like state. In contrast to cells in G(1), colcemid-arrested cells have decreased G(1) cyclin-dependent kinase activity and show hypophosphorylation of the retinoblastoma protein. We have found that overexpression of c-myc causes colcemid-treated human and rodent cells to become either apoptotic or polyploid by replicating DNA without chromosomal segregation. Although c-myc-induced polyploidy is not inhibited by wild-type p53 in immortalized murine fibroblasts, overexpression of c-myc in primary fibroblasts resulted in massive apoptosis of colcemid-treated cells. We surmise that additional genes are altered in immortalized cells to suppress the apoptotic pathway and allow c-myc-overexpressing cells to progress forward in the presence of colcemid. Our results also suggest that c-myc induces DNA rereplication in this G(1)-like state by activating CDK2 activity. These observations indicate that activation of c-myc may contribute to the genomic instability commonly found in human cancers. PMID: 10409725 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 561: Biochem Pharmacol. 1999 Jul 1;58(1):193-200. Differential apoptosis by indomethacin in gastric epithelial cells through the constitutive expression of wild-type p53 and/or up-regulation of c-myc. Zhu GH, Wong BC, Ching CK, Lai KC, Lam SK. Department of Medicine, Queen Mary Hospital, The University of Hong Kong, PR, China. Nonsteroidal anti-inflammatory drug (NSAID)-induced apoptosis is considered to be an important mechanism in the antineoplastic effects and damage produced by the drugs in the gastrointestinal tract. In this study, two different gastric cancer cell lines, MKN28 (mutant-type p53) and AGS (wild-type p53), were compared as to growth inhibition, apoptosis, and cell cycle and apoptosis-related gene expression in response to indomethacin treatment. Cell growth was measured by MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Apoptosis was characterized by acridine orange staining and DNA fragmentation, and cell cycle kinetics by flow cytometry. The mRNA and protein levels of p53, p21waf1/cip1, and c-myc were determined by Northern and Western blotting. The results showed that indomethacin initiated growth inhibition and apoptosis in both cell lines without cell cycle shifting. AGS cells were more sensitive to growth inhibitory activity and apoptosis of indomethacin than MKN28 cells. In MKN28 cells, the levels of p53, p21waf1/cip1, and c-myc mRNA remained unchanged over the 24-hr treatment with indomethacin, but the p53 protein level was elevated after 4 hr. There was no change in the p21waf1/cip1 and c-myc protein levels in the MKN28 cells. In AGS cells, a progressive increase in c-myc mRNA and protein levels was noted, while p53 and p21waf1/cip1 remained unchanged. It can be concluded that wild-type p53 and/or up-regulation of c-myc is associated with indomethacin-mediated differential apoptosis in gastric epithelial cells. PMID: 10403534 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 562: Oncogene. 1999 Jun 17;18(24):3564-73. Bin1 functionally interacts with Myc and inhibits cell proliferation via multiple mechanisms. Elliott K, Sakamuro D, Basu A, Du W, Wunner W, Staller P, Gaubatz S, Zhang H, Prochownik E, Eilers M, Prendergast GC. The Wistar Institute, Philadelphia, Pennsylvania 19104, USA. The tumor suppressor Bin1 was identified through its interaction with the N-terminal region of Myc which harbors its transcriptional activation domain. Here we show that Bin1 and Myc physically and functionally associate in cells and that Bin1 inhibits cell proliferation through both Myc-dependent and Myc-independent mechanisms. Bin1 specifically inhibited transactivation by Myc as assayed from artificial promoters or from the Myc target genes ornithine decarboxylase (ODC) and alpha prothymosin (pT). Inhibition of ODC but not pT required the presence of the Myc binding domain (MBD) of Bin1 suggesting two mechanisms of action. Consistent with this possibility, a non-MBD region of Bin1 was sufficient to recruit a repression function to DNA that was unrelated to histone deacetylase. Regions outside the MBD required for growth inhibition were mapped in Ras cotransformation or HepG2 hepatoma cell growth assays. Bin1 required the N-terminal BAR domain to suppress focus formation by Myc whereas the C-terminal U1 and SH3 domains were required to inhibit adenovirus E1A or mutant p53, respectively. All three domains contributed to Bin1 suppression of tumor cell growth but BAR-C was most crucial. These findings supported functional interaction between Myc and Bin1 in cells and indicated that Bin1 could inhibit malignant cell growth through multiple mechanisms. PMID: 10380878 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 563: Cancer. 1999 Jun 15;85(12):2668-9. Comment on: Cancer. 1998 Oct 1;83(7):1401-8. Expression of ras, c-myc, and p53 proteins in cervical intraepithelial neoplasia. Marangoz S, Gullu IH. Publication Types: Comment Letter PMID: 10375117 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 564: Zhonghua Bing Li Xue Za Zhi. 1997 Dec;26(6):343-5. [Expression of p53, c-erbB1, c-myc and p16 gene proteins in human glioma] [Article in Chinese] Zhu R, Kang S, Wu D. Department of Pathology, First Hospital Affiliated to Suzhou Medical College. OBJECTIVE: To realize the significance of c-erbB1 and c-myc protooncogenes, p53 and p16 tumor suppressor genes in the development and pathologic diagnosis of human glioma. METHODS: The expression of p53, c-erbB1, c-myc and p16 gene proteins was detected immunohistochemically in 65 cases of glioma. The relationship between these results and the pathological grades was determined. RESULTS: The overexpression of mutant p53, c-erbB1 and c-myc was in accordance with the increasing grade of glioma malignancy, showing significant difference (P < 0.05) between the benign group and highly malignant group in p53 and c-erbB1, while the deletion of p16 protein was more frequent in the highly malignant group than in any other group. These 4 genes showed co-expression in some of the gliomas. CONCLUSIONS: The 4 genes, especially p53 and c-erbB1, play an important role in the development of glioma; the detection of these gene proteins has a positive significance on malignancy determination for glioma. PMID: 10374323 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 565: Anticancer Res. 1999 Mar-Apr;19(2A):1181-5. Different H2 haplotypes have a strong influence on oncogene action. Ember I, Kiss I, Nowrasteh G. Department of Preventive Medicine, University Medical School of Pecs, Hungary. ember@pubhealth.pote.hu The H2 complex has an important role in determining susceptibility to viral and chemical leukemogenesis in inbred mice. This also applies to transplantable leukemias, within the syngeneic system. In this respect H2K is sensitive, H2d is relatively sensitive, and H2b is absolutely resistant to leukemia induction and transplantation. In our present study we investigated the effect of Cyclophosphamide, (a known chemical leukemogen) on onco/suppressor gene expression in CBA/Ca mice, very shortly after treatment with chemical carcinogen without any manifestation of tumour/leukemia symptoms. Here we describe, in a "short-term" experiment, the gene expression of Ha-ras, c-myc and p53 which was similar to the leukemia induction in a "long-term" experiment. H2K showed marked elevation in terms of onco/suppressor gene expression. H2b expression was modest and H2d turned out to be more or less silent. The results obtained from a short term gene expression investigation shows similarity to those obtained earlier from long term leukemia inducing experiments. PMID: 10368672 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 566: Oncogene. 1999 May 6;18(18):2892-900. Association with Cdc2 and inhibition of Cdc2/Cyclin B1 kinase activity by the p53-regulated protein Gadd45. Zhan Q, Antinore MJ, Wang XW, Carrier F, Smith ML, Harris CC, Fornace AJ Jr. Laboratory of Biological Chemistry, Division of Basic Science, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. Recently Gadd45, a p53-regulated stress protein, has been implicated in the activation of a G2/M checkpoint after damage by UV radiation and alkylating agents. While inhibitory phosphorylation of Cdc2 and suppression of cyclin B1 levels are known to be involved in G2 delays after genotoxic stress, Gadd45 has now been found to directly inhibit the activity of Cdc2/Cyclin B1 complex, while it had no appreciable effect on Cdk2/ Cyclin E activity even at very high levels of Gadd45. In contrast, p21CiP1/Waf1 is an universal cdk/cyclin inhibitor and inhibited both of the cyclin complexes tested here. Gadd45 was also able to physically interact with Cdc2, but not Cyclin B1. Addition of Gadd45 to immunoprecipitated Cdc2/Cyclin B1 in vitro led to a dissociation of this complex, and thus may represent a new checkpoint mechanism whereby Cdc2/Cyclin B1 can be inhibited. With the use of an antisense approach, reduced Gadd45 expression attenuated the suppression of Cdc2/Cyclin B1 activity in UV-irradiated human cells. Taken together, these results implicate Gadd45 in the control of G2/M cell cycle progression after certain stresses. PMID: 10362260 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 567: Genes Dev. 1999 Jun 1;13(11):1367-81. c-Myc-induced sensitization to apoptosis is mediated through cytochrome c release. Juin P, Hueber AO, Littlewood T, Evan G. Imperial Cancer Research Fund, London WC2A 3PX, UK. Expression of c-Myc sensitizes cells to a wide range of pro-apoptotic stimuli. We here show that this pro-apoptotic effect is mediated through release of mitochondrial holocytochrome c into the cytosol. First, activation of c-Myc triggers release of cytochrome c from mitochondria. This release is caspase-independent and blocked by the survival factor IGF-1. Second, c-Myc-induced apoptosis is blocked by microinjection of anticytochrome c antibody. In addition, we show that microinjection of holocytochrome c mimics the effect of c-Myc activation, sensitizing cells to DNA damage and to the CD95 pathway. Both p53 and CD95/Fas signaling have been implicated in c-Myc-induced apoptosis but neither was required for c-Myc-induced cytochrome c release. Nonetheless, inhibition of CD95 signaling in fibroblasts did prevent c-Myc-induced apoptosis, apparently by obstructing the ability of cytosolic cytochrome c to activate caspases. We conclude that c-Myc promotes apoptosis by causing the release of cytochrome c, but the ability of cytochrome c to activate apoptosis is critically dependent upon other signals. PMID: 10364155 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 568: Leukemia. 1999 Jun;13(6):873-6. B cell prolymphocytic leukaemia (B-PLL) with complex karyotype and concurrent abnormalities of the p53 and c-MYC gene. Lens D, Coignet LJ, Brito-Babapulle V, Lima CS, Matutes E, Dyer MJ, Catovsky D. Academic Department of Haematology and Cytogenetics, Royal Marsden Hospital/Institute of Cancer Research, Sutton, UK. We report the cytogenetic, molecular and biological characterization of a case of B-PLL with a complex karyotype and concurrent abnormalities on the p53 and c-MYC genes. Conventional cytogenetics suggested that both 17q arms were translocated to chromosomes 1q and 14p, respectively, whereas both 17p arms were not identified. In addition, a Burkitt's-like variant translocation t(2;8) was found. Study of loss of heterozygosity at 17p13 and p53 direct sequencing demonstrated the presence of only one copy of the p53 gene. A 27 bp deletion in exon 8 that resulted in the expression of a p53 protein lacking nine amino acids from the DNA binding region was also found. To confirm the presence of one copy of the p53 gene and localize it, fluorescent in situ hybridization (FISH) studies using a p53 gene probe was performed. Only one signal of p53 was visualized. Moreover, the DAPI profile of the chromosome containing the hybridization spot for the p53 probe did correspond to the cytogenetic marker identified as der(14)t(14;17). Whole chromosome 14 paint, centromere-specific for chromosome 17 and p53 gene probes were cohybridized to the preparations. This demonstrated that the der(14) contained the 17 centromere and distally the p53 gene suggesting that the der(14) contained the short arm of chromosome 17 with the breakpoint occurring in the long arm. FISH studies confirmed the involvement of c-MYC and KAPPA in the t(2;8) translocation. To our knowledge, this is the first case of B-PLL with inactivation of the p53 gene by mutation together with a Burkitt's-like t(2;8) translocation involving the c-MYC gene. The cooperation of these genes may have conferred a growth advantage which was critical in the development of this aggressive form of B-PLL. Publication Types: Case Reports PMID: 10360375 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 569: Oncogene. 1999 May 27;18(21):3213-25. Repression of NF-kappaB impairs HeLa cell proliferation by functional interference with cell cycle checkpoint regulators. Kaltschmidt B, Kaltschmidt C, Hehner SP, Droge W, Schmitz ML. Molecular Neurobiology Laboratory, Institute of Anatomy, Albert-Ludwigs-University, Freiburg, Germany. NF-kappaB is an inducible transcription factor, which is regulated by interaction with inhibitory IkappaB proteins. Previous studies linked the activity of NF-kappaB to the proliferative state of the cell. Here we have analysed the function of NF-kappaB in the cell cycle. Inhibition of NF-kappaB in HeLa cells by stable overexpression of a transdominant negative IkappaB-alpha protein reduced cell growth. A kinetic analysis of the cell cycle revealed a retarded G1/S transition. The IkappaB-alpha overexpressing cell clones showed a decreased percentage of cells in the S phase and an impaired incorporation of bromodeoxyuridine (BrdU). The amounts of cyclins A, B1, D1, D3, and E were unchanged, but the G1-specific proteins cyclin D2 and cdk2 were strongly elevated in the IkappaB-alpha overexpressing cell clones. These cell clones also displayed an increase in cyclin D1-dependent kinase activity, pointing to a cell cycle arrest at the late G1 phase. IkappaB-alpha overexpression crosstalked to cell cycle checkpoints via a reduction of transcription factor p53 and elevation of p21WAF. Surprisingly, the IkappaB-alpha overexpressing cells showed an enrichment of c-Myc in the nucleoli, although the total amount of c-Myc protein was unchanged. These experiments identify an important contribution of the NF-kappaB/IkappaB system for the growth of HeLa cells. PMID: 10359527 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 570: Cell Growth Differ. 1999 May;10(5):287-94. Nuclear factor kappaB cooperates with c-Myc in promoting murine hepatocyte survival in a manner independent of p53 tumor suppressor function. Bellas RE, Sonenshein GE. Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA. The nuclear factor-kappaB (NF-kappaB)/Rel family of transcription factors has been implicated in promoting hepatocyte survival during development and liver regeneration following partial hepatectomy. Inhibition of NF-kappaB/Rel activity by microinjection of the specific inhibitor IkappaB-alpha induces apoptosis in a nontransformed normal murine hepatocyte (NMH) cell line. Here, we demonstrate that apoptosis resulting from such inhibition requires down-regulation of the c-Myc proto-oncoprotein and occurs independently of p53 tumor suppressor function. NMH cells plated at low density displayed low sensitivity to IkappaB-alpha-induced apoptosis and high levels of c-Myc protein expression. Comicroinjection of IkappaB-alpha with the c-Myc antagonist Mad1-glutathione S-transferase fusion protein greatly enhanced cell death. In addition, transient cotransfection of low-density NMH and AML12 hepatocytes with vectors expressing IkappaB-alpha and antisense c-myc transcripts promoted cell death. Conversely, ectopic c-myc expression significantly decreased the extent of cell death in NMH cells plated at saturating density, which were characterized by very low levels of c-Myc and high susceptibility to NF-kappaB inhibition-induced cell death. Finally, IkappaB-alpha-induced apoptosis was unaffected in NMH cells expressing a dominant negative p53 protein. Thus, NF-kappaB cooperates with c-Myc in promoting murine hepatocyte survival in a manner independent of p53 tumor suppressor activity. PMID: 10359010 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 571: Oncogene. 1999 Apr 29;18(17):2728-38. Expression of human p53 requires synergistic activation of transcription from the p53 promoter by AP-1, NF-kappaB and Myc/Max. Kirch HC, Flaswinkel S, Rumpf H, Brockmann D, Esche H. Institute of Molecular Biology (Cancer Research), University of Essen, Medical School, Germany. Transcriptional control of p53 expression participates in the generation of appropriate levels of active p53 in response to mitogenic stimulation. This prompted us to study the role of a putative AP-1 and a NF-kappaB motif in the human p53 promoter for transcriptional regulation. We show that mutation of the AP-1 or the NF-kappaB motif abolishes transcription from the human p53 promoter in HeLa, HepG2 and adenovirus type 5 E1-transformed 293 cells. In comparison, mutation of the previously characterized Myc/Max/USF binding site in the human p53 promoter reduces the transcription rate fivefold. The AP-1 motif in the human p53 promoter binds c-Fos and c-Jun and the NF-kappaB motif binds p50(NF-kappaB) and p65RelA. The cooperative nature of transcriptional activation by these factors was documented by repression of c-fos or NF-kappaB1 translation: Pretreatment of the cells with a c-fos or p50(NF-kappaB1) antisense oligonucleotide suppresses transcription from the human p53 promoter completely. In addition, we show that (a) the level of endogenous p53 mRNA and (b) transcription from the strictly p53-dependent human mdm2 promoter are reduced in the presence of c-fos, c-jun, p50(NF-kappaB1), p65RelA or c-myc antisense oligonucleotides, underscoring the importance of these transcription factors for the expression of functional p53. PMID: 10348347 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 572: Cancer Res. 1999 May 15;59(10):2464-9. Loss of the ARF tumor suppressor reverses premature replicative arrest but not radiation hypersensitivity arising from disabled atm function. Kamijo T, van de Kamp E, Chong MJ, Zindy F, Diehl JA, Sherr CJ, McKinnon PJ. Howard Hughes Medical Institute, and Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. The alternative reading frame product (p19ARF) of the mouse INK4a/ARF locus is induced by oncoproteins such as Myc and E1A as part of a checkpoint response that limits cell cycle progression in response to hyperproliferative signals. ARF binds directly to Mdm2 to prevent down-regulation of p53 and thereby promotes p53-dependent transcription and cell cycle arrest. However, ARF is not required for p53 induction in response to ionizing radiation or other forms of DNA damage. Animals lacking a functional ataxia telangiectasia (Atm) gene are exquisitely sensitive to ionizing radiation; Atm-null mouse embryo fibroblasts (MEFs) undergo premature replicative arrest, which is relieved by the loss of p53. Here we show that the loss of ARF expands the life expectancy of Atm-null MEFs, but alters neither the sensitivity of Atm-null mice to ionizing radiation nor their propensity to develop lymphomas early in life. Therefore, whereas ARF and Atm signal to p53 through distinct pathways, the loss of ARF can modify p53-dependent features of the Atm-null phenotype. PMID: 10344759 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 573: Int J Mol Med. 1999 Jun;3(6):585-9. Variable expression and absence of mutations in p73 in primary neuroblastoma tumors argues against a role in neuroblastoma development. Ejeskar K, Sjoberg RM, Kogner P, Martinsson T. Department of Clinical Genetics, University of Gothenburg, Sahlgrenska University Hospital/East, S-416 85 Gothenburg, Sweden. In neuroblastoma, a childhood tumor of neural crest, a tumor suppressor gene located at 1p36 has been implicated to play a major role in tumor aggressiveness and clinical prognosis. We have examined 30 different staged primary neuroblastoma tumors using RT-PCR, for expression of the p73 gene located at 1p36.3, and its correlation to other clinical and biological features of these tumors. No correlation between expression of p73 and MYCN-amplification or 1p-deletion could be found, five of ten 1p-deleted tumors showed detectable levels of p73, and no mutations could be detected, neither in the retained alleles nor in any other parts of the material. In five 1p-deleted cases the origin of deletion were determined, two were of maternal and three of paternal origin. Both tumors with maternal 1p-loss showed detectable levels of p73, whereas the three with paternal loss did not. This suggests that p73 is expressed from the paternal allele only in advanced staged neuroblastoma tumors. Furthermore, it suggests absence of correlation between p73-expression and stage in these tumors. In conclusion, we could find no evidence for p73 being the neuroblastoma tumor suppressor gene in 1p36. PMID: 10341287 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 574: Mol Carcinog. 1999 May;25(1):30-41. Analysis of oncogene, tumor suppressor gene, and chromosomal alterations in HeLa x osteosarcoma somatic cell hybrids. Isfort RJ, Cody DB, Lovell GJ, Gioeli D, Weissman BE, Doersen CJ. Human Safety Department, The Proctor & Gamble Company, Miami Valley Laboratories, Cincinnati, Ohio, USA. Using a series of tumorigenic and non-tumorigenic somatic cell hybrids that resulted from the fusion of the human osteosarcoma cell line OHS50-P16T (P16T) with the HeLa cell line D98OR, we investigated the role that genetic mutations, including alterations of oncogenes, tumor suppressor genes, and chromosomes, play in P16T tumorigenicity. Analysis of a previously identified oncogene mutation, c-myc amplification, in the P16T cell line demonstrated that both the tumorigenic and non-tumorigenic hybrids contained the amplified c-myc gene. Analysis of previously identified P16T tumor suppressor gene alterations, p53 mutation, and loss of RB1 expression demonstrated that the mutated p53 gene was selectively maintained in both the non-tumorigenic and tumorigenic hybrids, whereas loss of RB1 expression was not maintained in either the non-tumorigenic or tumorigenic hybrids. Chromosomes 11, 13, 17, and 22 were analyzed for loss of heterozygosity (LOH) to characterize the status of these previously described chromosomal alterations in the tumorigenic and non-tumorigenic hybrids. Loss of HeLa D98OR chromosome 22, with maintenance of P16T chromosome 22, was observed in the tumorigenic hybrids, a result confirmed by LOH analysis, which demonstrated the specific loss of HeLa chromosome 22 genetic material in the tumorigenic segregants. Together, these results demonstrated that amplified c-myc, mutant p53, and RB1 genes seem to be important in osteosarcoma tumorigenicity and that an additional altered gene or genes on chromosome 22 may play a key role in osteosarcoma tumorigenicity. PMID: 10331742 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 575: Oncogene. 1999 Apr 1;18(13):2181-8. c-Myc and E1A induced cellular sensitivity to activated NK cells involves cytotoxic granules as death effectors. Klefstrom J, Kovanen PE, Somersalo K, Hueber AO, Littlewood T, Evan GI, Greenberg AH, Saksela E, Timonen T, Alitalo K. Biochemistry of the Cell Nucleus Laboratory, Imperial Cancer Research Fund, London, UK. The contact of natural killer (NK) cells with foreign cells and with certain virus-infected or tumor cells triggers the cytolytic machinery of NK cells. This triggering leads to exocytosis of the cytotoxic NK cell granules. The oncoproteins c-Myc and E1A render cells vulnerable to NK cell mediated cytolysis yet the mechanisms of sensitization are not well understood. In a model where foreign cells (rat fibroblasts) were cocultured with human IL-2 activated NK cells, we observed that NK cells were capable of efficiently killing their targets only if the cells overexpressed the oncogene c-Myc or E1A. Both the parental and the oncogene expressing fibroblasts similarly triggered phosphoinositide hydrolysis in the bound NK cells, demonstrating that NK cells were cytolytically activated in contact with both resistant parental and oncogene expressing sensitive target fibroblasts. The cell death was independent of wild-type p53 and was not inhibited by an anti-apoptotic protein EIB19K. These results provided evidence that c-Myc and E1A activated the NK cell induced cytolysis at a post-triggering stage of NK cell-target cell interaction. In consistence, the c-Myc and E1A overexpressing fibroblasts were more sensitive to the cytolytic effects of isolated NK cell-derived granules than parental cells. The data indicate that oncogenes activate the cytotoxicity of NK cell granules. This mechanism can have a role in directing the cytolytic action of NK cells towards the virus-infected and cancer cells. PMID: 10327064 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 576: Gut. 1999 Jun;44(6):789-99. Erratum in: Gut 2000 Apr;46(4):584. Effect of Helicobacter pylori infection and its eradication on cell proliferation, DNA status, and oncogene expression in patients with chronic gastritis. Nardone G, Staibano S, Rocco A, Mezza E, D'armiento FP, Insabato L, Coppola A, Salvatore G, Lucariello A, Figura N, De Rosa G, Budillon G. Dipartimento di Patologia Sistematica, Cattedra di Gastroenterologia, Universita degli Studi "Federico II", via Pansini 5, 80131 Naples, Italy. BACKGROUND: Helicobacter pylori, the main cause of chronic gastritis, is a class I gastric carcinogen. Chronic gastritis progresses to cancer through atrophy, metaplasia, and dysplasia. Precancerous phenotypic expression is generally associated with acquired genomic instability. AIM: To evaluate the effect of H pylori infection and its eradication on gastric histology, cell proliferation, DNA status, and oncogene expression. METHODS/SUBJECTS: Morphometric and immunohistochemical techniques were used to examine gastric mucosal biopsy specimens from eight controls, 10 patients with H pylori negative chronic gastritis, 53 with H pylori positive chronic gastritis, and 11 with gastric cancer. RESULTS: All patients with chronic gastritis were in a hyperproliferative state related to mucosal inflammation, regardless of H pylori infection. Atrophy was present in three of 10 patients with H pylori negative chronic gastritis and in 26 of 53 with H pylori positive chronic gastritis, associated in 18 with intestinal metaplasia. DNA content was abnormal in only 11 patients with atrophy and H pylori infection; eight of these also had c-Myc expression, associated in six cases with p53 expression. Fifty three patients with H pylori positive chronic gastritis were monitored for 12 months after antibiotic treatment: three dropped out; infection was eradicated in 45, in whom cell proliferation decreased in parallel with the reduction in gastritis activity; atrophy previously detected in 21/45 disappeared in five, regressed from moderate to mild in nine, and remained unchanged in seven; complete metaplasia disappeared in 4/14, and markers of genomic instability disappeared where previously present. In the five patients in whom H pylori persisted, atrophy, metaplasia, dysplasia, and markers of genomic instability remained unchanged. CONCLUSIONS: Chronic H pylori infection seems to be responsible for genomic instability in a subset of cases of H pylori positive chronic atrophic gastritis; eradication of H pylori infection can reverse inflammation and the related atrophy, metaplasia, and genomic instability. PMID: 10323879 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 577: Cytometry. 1999 Apr 15;38(2):53-60. c-MYC, RB-1, TP53, and centromere 8 and 17 copy number in B-cell non-Hodgkin's lymphomas assessed by dual-color fluorescence in situ hybridization. Galteland E, Holte H, Stokke T. Department of Biophysics, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway. Dual-color interphase FISH was performed to B-cell Non-Hodgkin's lymphomas to detect numerical genetic alterations in c-MYC, RB-1, TP53 and centromere 8 and 17. The probe combinations c-MYC/centromere 8, RB-1/centromere 8 and TP53/centromere 17 were applied, and the hybridization signals scored in a correlated fashion. Copy number aberrations was found in 24 of 45 lymphomas examined (53%). Nine tumors (20%) had increased c-MYC gene copy number (three to 8 copies). Seven of these nine had increase in c-MYC copies relative to centromere 8 copy number. Allelic loss of RB-1 was found in 9 tumors (20%), one tumor lacked both alleles. Nine cases (20%) showed hemizygous TP53 deletion. TP53 deletion was significantly associated with high-grade histology (P = 0.02). Numerical alterations in c-MYC and RB-1 were not associated with prognosis. Patients with hemizygous TP53 deletion had shorter survival (relative risk = 6.1, P<0.001) than the ones with two or more alleles. PMID: 10323217 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 578: Cell Res. 1999 Mar;9(1):51-9. Mad-overexpression down regulates the malignant growth and p53 mediated apoptosis in human hepatocellular carcinoma BEL-7404 cells. Zhao H, Xu YH. Shanghai Institute of Cell Biology, Chinese Academy of Sciences. Mad protein has been shown as an antagonist of c-Myc protein in some cell lines. The effect of Mad protein to the malignant phenotype of human hepatoma BEL-7404 cell line was investigated experimentally. An eukarryotic vector pCDNA III containing full ORF fragment of mad cDNA was transfected into targeted cells. Under G418 selection, stable Mad-overexpressed cells were cloned. Studies on the effect of Mad over-expression in cell proliferation and cell cycle revealed that cell morphology of the Mad-overexpressed BEL-7404-M1 cells was significantly different from the parent and control vector transfected cells. DNA synthesis, cell proliferation and anchorage-independent growth in soft-agar of the mad-transfected cells were partially inhibited in comparison to control cells. Flow Cytometry analysis indicated that mad over-expression might block more transfectant cells at G0/G1 phase, resulting in the retardation of cell proliferation. RT-PCR detected a marked inhibition of the expression of cdc25A, an important regulator gene of G0/G1 to S phase in cell cycle. It was also found that Mad protein overexpression could greatly suppress p53-mediated apoptosis in BEL-7404-M1 cells in the absence of serume. Thus, Mad proteins may function as a negative regulator antagonizing c-Myc activity in the control of cell growth and apoptosis in human hepatocellular carcinoma BEL-7404 cells. PMID: 10321688 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 579: J Neurosci. 1999 May 15;19(10):4023-33. Nuclear factor kappaB nuclear translocation upregulates c-Myc and p53 expression during NMDA receptor-mediated apoptosis in rat striatum. Qin ZH, Chen RW, Wang Y, Nakai M, Chuang DM, Chase TN. Experimental Therapeutics Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA. Nuclear factor kappaB (NF-kappaB) appears to participate in the excitotoxin-induced apoptosis of striatal medium spiny neurons. To elucidate molecular mechanisms by which this transcription factor contributes to NMDA receptor-triggered apoptotic cascades in vivo, rats were given the NMDA receptor agonist quinolinic acid (QA) by intrastriatal infusion, and the role of NF-kappaB in the induction of apoptosis-related genes and gene products was evaluated. QA administration induced time-dependent NF-kappaB nuclear translocation. The nuclear NF-kappaB protein after QA treatment was comprised mainly of p65 and c-Rel subunits as detected by gel supershift assay. Levels of c-Myc and p53 mRNA and protein were markedly increased at the time of QA-induced NF-kappaB nuclear translocation. Immunohistochemical analysis showed that c-Myc and p53 induction occurred in the excitotoxin-sensitive medium-sized striatal neurons. NF-kappaB nuclear translocation was blocked in a dose-dependent manner by the cell-permeable recombinant peptide NF-kappaB SN50, but not by the NF-kappaB SN50 control peptide. NF-kappaB SN50 significantly inhibited the QA-induced elevation in levels of c-Myc and p53 mRNA and protein. Pretreatment or posttreatment with NF-kappaB SN50, but not the control peptide, also substantially reduced the intensity of QA-induced internucleosomal DNA fragmentation. The results suggest that NF-kappaB may promote an apoptotic response in striatal medium-sized neurons to excitotoxic insult through upregulation of c-Myc and p53. This study also provides evidence indicating an unique signaling pathway from the cytoplasm to the nucleus, which regulates p53 and c-Myc levels in these neurons during apoptosis. PMID: 10234031 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 580: Leukemia. 1999 Apr;13 Suppl 1:S83-6. Identification of murine CBF alpha1, a runt domain transcription factor, as a putative Myc collaborator in T cell lymphoma. Neil J, Stewart M, Terry A, O'Hara M, Hu M, Blyth K, Baxter E, Onions D, Cameron E. Molecular Oncology Laboratory, University of Glasgow Veterinary School, Bearsden, UK. PMID: 10232373 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 581: Oncol Res. 1998;10(9):455-64. Effect of ionizing radiation on wild-type and mutant mouse leukemia L1210 cells. He AW, Cory JG. Department of Biochemistry, East Carolina University, School of Medicine, Greenville, NC 27858, USA. Wild-type (WT) mouse leukemia L1210 cells express steady-state levels of p53 mRNA and protein. However, the p53 expressed by the wild-type L1210 cells was found to be a mutant form of p53 (relative to normal mouse fibroblast p53 sequence) having a point mutation in the DNA binding domain of p53. A deoxyadenosine-resistant L1210 cell line (Y8) derived from the parental WT cells had previously been shown to lack the expression of p53 but to respond to cycloheximide (CHX) treatment by superinduction of p53 mRNA. The mRNA for p53 induced by CHX had the same sequence as the p53 from normal mouse fibroblasts. Although the Y8 cells had no constitutive levels of p53 mRNA or protein, the Y8 cells expressed constitutive levels of WAF1 mRNA and protein. Gadd45 mRNA was also present in the Y8 cells. Subjecting the WT or Y8 cells to ionizing radiation did not result in a G0/G1 cell cycle block; the cells blocked in G2/M. The Y8 cells were much more sensitive to the irradiation treatment than the WT cells, resulting in marked increases in apoptosis in the Y8 cells. Although radiation treatment induced p53 mRNA, but no p53 protein, in the Y8 cells, WAF1 mRNA was induced in the Y8 cells. These data indicate that there are p53-independent pathway(s) that may still involve WAF1 and Gadd45 with respect to cell cycle control and apoptosis. PMID: 10223621 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 582: J Neurosurg. 1999 May;90(5):918-27. Effects of clotrimazole on the growth, morphological characteristics, and cisplatin sensitivity of human glioblastoma cells in vitro. Khalid MH, Shibata S, Hiura T. Department of Neurosurgery, Nagasaki University School of Medicine, Japan. humayun@net.nagasaki-u.ac.jp OBJECT: Clotrimazole, an antimycotic drug, inhibits proliferation of normal and cancer cells by downregulating the movement of intracellular Ca++ and K+. The authors examined the effect of clotrimazole on the growth and sensitivity to cisplatin of two human glioblastoma cell lines--A172, which has the wild-type p53 gene, and T98G, which has the mutant p53 gene in vitro. METHODS: The A172 and T98G glioblastoma cells were exposed to clotrimazole and cell growth was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium chloride colorimetric assay. Clotrimazole produced a dose-dependent inhibition of cell proliferation and caused changes in cellular structure toward a well-differentiated form. The growth inhibitory effect of clotrimazole was reversible. Western immunoblot analysis revealed a marked increase in cellular glial fibrillary acidic protein and wild-type p53 and a decrease in c-myc and c-fos oncoproteins in both cell lines treated with clotrimazole. Flow cytometric analysis revealed that clotrimazole-treated cells accumulated in the G0/G1 phase with a marked decrease in cells in the S phase; when clotrimazole was washed out from the culture medium, cells again started to proliferate, with a marked decrease in cells in the G0/G1 phase and an increase in cells in the S phase. The growth inhibitory effect of clotrimazole could not be overcome by exogenous stimulation with either epidermal growth factor or c-myc peptide. A combined treatment with clotrimazole and cisplatin significantly enhanced cell cytotoxicity compared with treatment using either drug alone. A DNA fragmentation assay showed that both clotrimazole and cisplatin induced apoptosis, which was increased in cells treated by both drugs. CONCLUSIONS: The present study indicates that clotrimazole inhibits cell proliferation accompanied by morphological changes toward differentiation of glioblastoma cells and that this drug synergistically enhances the antitumor effect of cisplatin by inducing wild-type p53-mediated apoptosis. PMID: 10223459 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 583: Genes Chromosomes Cancer. 1999 May;25(1):53-9. Molecular cytogenetic analysis of the bladder carcinoma cell line BK-10 by spectral karyotyping. Padilla-Nash HM, Nash WG, Padilla GM, Roberson KM, Robertson CN, Macville M, Schrock E, Ried T. Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. hnash@nhgri.nih.gov The bladder cancer cell line BK-10 was established from a grade III-IV transitional cell carcinoma (TCC). BK-10 is near-tetraploid (+/-4n) and consists of two subclones with 20-25 structural aberrations. Here we report the cytogenetic analysis of BK-10 by G-banding, spectral karyotyping (SKY), and FISH. SKY refers to the hybridization of 24 differentially labeled chromosome painting probes and the simultaneous visualization of all human chromosomes using spectral imaging. SKY enabled us to confirm 12 markers in BK-10 previously described by G-banding, redefine 11 aberrations, and detect 4 hidden chromosomal rearrangements, 2 of which had been identified as normal or deleted copies of chromosome 20 and 1 as a normal chromosome 3. Twenty out of 21 translocations identified were unbalanced. FISH analysis of BK-10 using chromosome arm-specific paints, centromere probes, and oncogene/tumor suppressor gene-specific probes revealed a deletion of CDKN2A (p16) in all copies of chromosome 9, a low-level amplification of MYC (five copies), and loss of one copy of TP53; detected the presence of the Y chromosome in a hidden translocation; and detected four copies of ERBB-2. A probe set for BCR and ABL verified breakpoints for all translocations involving chromosomes 9 and 22. A new karyotype presentation, "SKY-gram," is introduced by combining data from G-banding, SKY, and FISH analysis. This study demonstrates the approach of combining molecular cytogenetic techniques to characterize fully the multiple complex chromosomal rearrangements found in the bladder cancer cell line BK-10, and to refine the chromosomal breakpoints for all translocations. PMID: 10221340 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 584: Asian Pac J Allergy Immunol. 1998 Dec;16(4):167-76. Study on the metastatic mechanisms of human giant-cell lung carcinoma comparison between the strains C and D. Mei L, Lezhen C, Po Z, Zheng G, Yali L, Nan L. Department of Pathology, Chinese PLA General Hospital, Beijing. The biologic characteristics of the two human giant-cell lung carcinoma strains with high (strain D) and low metastatic potential (strain C) were studied, including karyotype of chromosome, intracellular free calcium ([Ca2+]i), morphologic changes of cell surface and the expression of nm23-H1, p53, ras, c-myc, c-erbB2, bcl-2 genes and PCNA. The correlation between different biologic features and the metastatic potential of the two strains was analyzed. We found: 1) Both strains had the karyotypic abnormality of -13, -14, -15, +20, +21 with seven same marker chromosomes. Only strain D had the karyotypic abnormality of +7, -17, -18, +X, 7p+; 2) [Ca2+]i of the strain C (984.7 +/- 573.8) and D (517.6 +/- 216.6) was significantly different (p < 0.05). The amplitude of intracellular calcium oscillations of strain C was lower than the one of strain D; 3) strain C had more villous-like protrusions on the cell surface, whereas strain D had more bubble-like protrusions; 4) The expression of nm23-H1 and p53 protein of strain C was all higher than that of strain D. The expression of PCNA of strain C was lower than strain D; 5) nm23-H1 mRNA levels of strain C was lower than that of strain D. We consider that the karyotype of chromosomes, intracellular free calcium, the structure of cell membrane and the expression of nm23-H1 gene, p53 gene, PCNA could be closely related to the metastatic potential of human giant-cell lung carcinoma. They could be used as the sign for judging whether the tumor will metastasize in clinical practice as well as in judging the prognoses of patients. PMID: 10219898 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 585: Lung Cancer. 1999 Feb;23(2):143-52. Study of prognostic predictors for non-small cell lung cancer. Fu XL, Zhu XZ, Shi DR, Xiu LZ, Wang LJ, Zhao S, Qian H, Lu HF, Xiang YB, Jiang GL. Lung Cancer Service, Cancer Hospital, Shanghai Medical University, China. BACKGROUND: The outcome of treatment in non-small cell lung cancer (NSCLC) remains poor. One of the reasons is that in many patients its biological behavior does not follow a definite pattern, and can not be accurately predicted prior to treatment. In the present study we have examined the significant prognostic predictors. METHODS: One hundred and fifty-eight patients with NSCLC entered this study. They received surgery alone (95 cases) or combined therapy with postoperative irradiation (63 cases). Three types of data have been collected: (1) clinical characteristics: age, sex, Karnofsky performance status, weight loss, T stage, and N stage; (2) histopathology studies: histological types, tumor differentiation, status of vascular and lymphatic vessel invasions; (3) laboratory measurements by immunohistochemistry assay: oncoprotein overexpression, including pan-ras, c-myc, neu, epidermal growth factor receptor (EGFR) and p53, and tumor cell proliferation by proliferating cell nuclear antigen (PCNA). RESULTS: For the entire group, 5-year actuarial survival, local control and distant metastasis rates were 44, 63 and 40%, respectively. In the univariate analyses, T stage, N stage and lymphatic vessel invasion correlated to survival; T stage and N stage to local control; N stage, lymphatic vessel invasion and pan-ras protein positive stain to distant metastasis. When the index of oncoprotein positive stains was used, the higher index was associated with a higher distant metastasis rate. In the multivariate analyses, T stage, N stage and lymphatic vessel invasion could be independent predictors for survival; T stage for local control; N stage, lymphatic vessel invasion and index of positive oncoprotein stains for distant metastasis. CONCLUSIONS: Late T and N stages, lymphatic vessel invasion and multi-oncoprotein positive stains would predict poor prognoses for NSCLC. PMID: 10217618 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 586: Br J Ophthalmol. 1999 Jan;83(1):110-4. c-myc, p53, and Bcl-2 expression and clinical outcome in uveal melanoma. Chana JS, Wilson GD, Cree IA, Alexander RA, Myatt N, Neale M, Foss AJ, Hungerford JL. Gray Laboratory, Mount Vernon Hospital, Northwood, Middlesex. AIMS: Overexpression of c-myc protein has independent prognostic significance in a variety of primary and metastatic cutaneous melanomas which suggests a possible role for this gene in melanomagenesis. We have therefore examined the importance of this oncogene in uveal melanoma and studied the coexpression of two other gene products, Bcl-2 and p53, which might contribute to its effect. METHODS: The percentage of cells positive for nuclear c-myc expression was estimated by flow cytometric analysis of nuclei extracted from paraffin blocks. The expression of Bcl-2 and p53 protein was assessed by immunohistochemistry. A total of 71 tumours were studied and the results compared with survival with a mean follow up period of 6 years. RESULTS: c-myc was expressed in > 50% of the cells by 70% of the tumours, and was independently associated with improved survival in a Cox multiple regression-model. Although Bcl-2 was expressed by the majority of the cells in 67% tumours, it was without effect on prognosis. None of the cases studied showed convincing positivity for p53. Analysis of coexpression showed that the best survival was seen in c-myc+/Bcl-2+ tumours and the worst in c-myc-/Bcl-2-tumours. CONCLUSION: The finding of improved rather than reduced survival in c-myc positive tumours is at variance with skin melanoma. There was no evidence to suggest that c-myc was modulated by upregulation of Bcl-2 or p53 inactivation/mutation. Although Bcl-2 is unlikely to have any effect on tumour growth or metastasis, it could contribute to the general lack of susceptibility to apoptosis in these tumours. PMID: 10209447 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 587: Cell Death Differ. 1998 Feb;5(2):141-7. Comment in: Cell Death Differ. 1998 Feb;5(2):129-31. p53 mediates apoptosis induced by c-Myc activation in hypoxic or gamma irradiated fibroblasts. Rupnow BA, Alarcon RM, Giaccia AJ, Knox SJ. Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305-5302, USA. Deregulated c-Myc expression leads to a cellular state where proliferation and apoptosis are equally favored depending on the cellular microenvironment. Since the apoptotic sensitivity of many cells is influenced by the status of the p53 tumor suppressor gene, we investigated whether the induction of apoptosis by DNA damage or non-genotoxic stress are also influenced by the p53 status of cells with altered c-Myc activity. Rat-1 fibroblasts expressing a conditional c-Myc allele (c-MycER), were transfected to express an antisense RNA complimentary to p53 mRNA. Expression of antisense p53 RNA decreased p53 protein levels and delayed p53 accumulation following c-Myc activation. Under hypoxic or low serum conditions, cells expressing antisense p53 were substantially more resistant to c-Myc-induced apoptosis than were control cells. c-Myc activation also sensitized Rat-1 cells to radiation-induced apoptosis. Rat-1 cells expressing antisense p53 RNA were more resistant to apoptosis induced by the combined effects of c-Myc activation and gamma irradiation. In a similar manner, apoptosis induced by c-Myc in serum starved, hypoxic or gamma irradiated fibroblasts was also inhibited by Bcl-2. These data indicate that p53 is involved in c-Myc-mediated apoptosis under a variety of stresses which may influence tumor growth, evolution and response to therapy. PMID: 10200458 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 588: Science. 1999 Apr 2;284(5411):156-9. Apaf-1 and caspase-9 in p53-dependent apoptosis and tumor inhibition. Soengas MS, Alarcon RM, Yoshida H, Giaccia AJ, Hakem R, Mak TW, Lowe SW. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA. The ability of p53 to promote apoptosis in response to mitogenic oncogenes appears to be critical for its tumor suppressor function. Caspase-9 and its cofactor Apaf-1 were found to be essential downstream components of p53 in Myc-induced apoptosis. Like p53 null cells, mouse embryo fibroblast cells deficient in Apaf-1 and caspase-9, and expressing c-Myc, were resistant to apoptotic stimuli that mimic conditions in developing tumors. Inactivation of Apaf-1 or caspase-9 substituted for p53 loss in promoting the oncogenic transformation of Myc-expressing cells. These results imply a role for Apaf-1 and caspase-9 in controlling tumor development. PMID: 10102818 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 589: Mod Pathol. 1999 Mar;12(3):279-86. Comparison of DNA ploidy, histologic, and immunohistochemical findings with clinical outcome in inflammatory myofibroblastic tumors. Hussong JW, Brown M, Perkins SL, Dehner LP, Coffin CM. Department of Pathology, University of Utah Health Sciences Center and Primary Children's Medical Center, Salt Lake City 84113-1100, USA. Inflammatory myofibroblastic tumors (IMTs) are uncommon spindle cell proliferations that occur in the viscera and soft tissue of children and young adults. Their biologic potential is indeterminate: 25% of IMTs recur, and rare examples undergo malignant transformation (MT). This study investigates histologic features, DNA ploidy, and expression of apoptotic regulatory and oncogenic proteins in IMTs in an attempt to identify those deviances that might correlate with aggressive behavior or MT. Twenty-four formalin-fixed, paraffin-embedded IMTs for which clinical outcome was known were evaluated for cellularity, cytologic atypia, mitoses, ganglion-like cells, inflammatory infiltrate, DNA ploidy by flow cytometric examination, and bax, bcl-2, p53, and c-myc expression by immunohistochemical analysis. Sixteen (67%) of the IMTs did not recur, 6 (25%) recurred, and 2 (8%) underwent MT. Cellular atypia was observed in 69% of the cases without recurrence, 100% with recurrence, and 100% with MT. Ganglion-like cells were present in 56, 100, and 100% of the IMTs without recurrence, with recurrence, and with MT, respectively. There was no difference in the degree of cellularity, mitoses, or inflammatory infiltrate among the outcome groups. All of the tumors expressed bax, and none expressed c-myc. Two (8%) were immunoreactive for p53, one of which recurred and one of which underwent MT. bcl-2 expression was observed in 9 (37%) of the IMTs, with no difference among the three groups. Two IMTs were aneuploid, one of which underwent MT. Neither morphologic evaluation for cellularity, mitosis, or inflammatory infiltrate nor expression of bax or c-myc were useful for prediction of clinical outcome. The combination of atypia, ganglion-like cells, p53 expression and DNA ploidy analysis, however, might be useful to identify IMTs that might undergo MT or pursue a more aggressive clinical course with recurrences. PMID: 10102613 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 590: Clin Cancer Res. 1999 Mar;5(3):577-86. Oncogene alterations in carcinomas of the uterine cervix: overexpression of the epidermal growth factor receptor is associated with poor prognosis. Kersemaekers AM, Fleuren GJ, Kenter GG, Van den Broek LJ, Uljee SM, Hermans J, Van de Vijver MJ. Department of Pathology, Leiden University Medical Center, The Netherlands. The involvement of human papillomavirus (HPV) in the development of carcinomas of the uterine cervix has been firmly established. However, other genetic alterations also play an important role in the pathogenesis of cervical cancer. Therefore, we have investigated the role of several (onco)genes in cervical carcinoma. In tumors from 136 patients with stage I and II cancer of the uterine cervix, the expression of epidermal growth factor receptor (EGFR), c-erbB-2/neu, p53, and murine double minute 2 (MDM-2) was studied using immunohistochemistry. In 32 cases, amplification of EGFR, c-erbB-2/neu, MDM-2, and c-myc was studied by Southern blot hybridization. The expression levels of these proteins were correlated with HPV positivity, International Federation of Gynecologists and Obstetricians stage, lymph node metastases, tumor diameter, vessel invasion, and disease-free and overall survival. Moderate/strong expression of EGFR was observed in 54% of tumors. c-erbB-2/neu was focally positive in 12 cases. p53 showed moderate/strong expression in 32% of the tumors. Thirteen % of tumors showed a moderate/strong expression of MDM-2, and this expression was correlated to p53 expression (P<0.001). Only moderate/strong expression of EGFR was associated with reduced disease-free (P = 0.002) and overall survival (P = 0.003). In multivariate analysis, the association of EGFR overexpression with poor prognosis was independent from lymph node status. Gene amplification was found for EGFR (four cases), c-erbB-2/ neu (two cases), and c-myc (six cases). In two tumors, rearrangement of c-myc was found, probably due to the integration of HPV. In conclusion, overexpression of the EGFR is an independent predictor for prognosis in earlier stages (stage I and II) of cervical cancer. p53 and MDM-2 expression are correlated to each other and may play a role in the interaction with HPV. The importance of c-erbB-2/neu and c-myc amplification is relatively small in stage I and II cervical cancer. PMID: 10100709 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 591: Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3993-8. Induction of ARF tumor suppressor gene expression and cell cycle arrest by transcription factor DMP1. Inoue K, Roussel MF, Sherr CJ. Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. Expression of the DMP1 transcription factor, a cyclin D-binding Myb-like protein, induces growth arrest in mouse embryo fibroblast strains but is devoid of antiproliferative activity in primary diploid fibroblasts that lack the ARF tumor suppressor gene. DMP1 binds to a single canonical recognition site in the ARF promoter to activate gene expression, and in turn, p19(ARF) synthesis causes p53-dependent cell cycle arrest. Unlike genes such as Myc, adenovirus E1A, and E2F-1, which, when overexpressed, activate the ARF-p53 pathway and trigger apoptosis, DMP1, like ARF itself, does not induce programmed cell death. Therefore, apart from its recently recognized role in protecting cells from potentially oncogenic signals, ARF can be induced in response to antiproliferative stimuli that do not obligatorily lead to apoptosis. PMID: 10097151 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 592: J Toxicol Environ Health A. 1999 Mar 26;56(6):397-404. Genetic alterations of cancer-related genes in glass fiber-induced transformed cells. Whong WZ, Gao HG, Zhou G, Ong T. Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia 26505-2888, USA. Our previous studies have shown that glass fibers induced morphological transformation in BALB/c-3T3 cells and that transformed cells possessed preneoplastic properties and transforming genes. In the current study, possible molecular mechanisms of glass fiber-induced cell transformation related to the activation and/or inactivation of cancer-related genes resulting from gene amplification and/or point mutations were investigated. Gene amplification was determined by Southern blot analysis of K-ras, H-ras, c-myc, and c-fos proto-oncogenes. Mutational spectra of the p53 tumor suppressor gene and the K-ras proto-oncogene were characterized by single-stranded conformation polymorphism and DNA sequencing. Southern blot analysis showed that gene amplification was found in 56% (K-ras and c-myc), 67% (c-fos), and 100% (H-ras) of glass fiber-transformed cell lines. DNA sequencing analysis revealed that both transition and transversion mutations occurred and were concentrated in exon 2 of K-ras and exon 4 of p53. In addition, multiple mutations in different codons were found in K-ras and p53 These results suggest that (1) glass fiber-induced cell transformation could be attributed to the activation of the H-ras, K-ras, c-myc, and c-fos proto-oncogenes and/or the inactivation of the p53 tumor suppressor gene by gene amplification and/or point mutations and (2) multiple mutations might be due to genomic instability resulting from chromosomal alterations induced by glass fibers. PMID: 10096362 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 593: Verh Dtsch Ges Pathol. 1998;82:133-43. [Genetic instability in osteoblastic tumors of the skeletal system] [Article in German] Roessner A, Radig K, Schneider-Stock R, Mittler U, Neumann HW. Institut fur Pathologie, Otto-von-Guericke-Universitat, Magdeburg. In the histological differential diagnosis of osteoblastic bone tumors, several problems could not have been solved by conventional histological methods including immunohistology. Some well-known examples are the differential diagnosis between aneurysmal bone cyst and telangiectatic osteosarcoma and giant cell tumor versus giant cell-containing highly malignant osteosarcoma. As a new approach to these diagnostic problems, we analyzed the genetic instability in a larger number of bone-forming tumor-like lesions, benign and malignant osteoblastic tumors. Analysis focused on genetic alterations in cell cycle regulator genes: Mutations in the p53 gene and ras gene, loss of heterozygosity at the p53, p16 and Rb-locus, and amplification of the mdm2 gene and the c-myc-gene. In addition to cell cycle regulators, the telomerase activity has also been analyzed. The results show that the number of genetic alterations increases with the malignancy of the tumors. The highest number of genetic alterations could thus be found in conventional intraosseous osteosarcoma. In tumor-like lesions, genetic alterations have rarely been observed. The results of this study show that the analysis of genetic instability will probably contribute to an improved differential diagnosis of osteoblastic tumors. Publication Types: Review Review, Tutorial PMID: 10095425 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 594: Ital J Gastroenterol Hepatol. 1999 Jan-Feb;31(1):73-7. Liver and apoptosis. Valente M, Calabrese F. Department of Pathology, University of Padua Medical School, Italy. mvalente@uxl.unipd.it Apoptosis is an energy-requiring mechanism of cell death which is a physiological event in organ morphogenesis, clone selection of lymphoid cells and cell turnover, but also occurs in many pathological conditions. It is under genetic control, bcl-2 being the major apoptosis suppressing gene, while p53 and c-myc are apoptosis promoting genes. Other factors, such as the Fas/Fas1 system, the caspases cascade, cytokines and enzymes also play a role in determining apoptosis. The term apoptosis was introduced by Kerr to describe this type of death in ischaemic rat liver, and the same Councilman bodies are now considered an example of apoptotic death. Virus-infected hepatocytes bear Fas receptors and apoptosis is induced by binding to the Fas ligand which is expressed by activated T cells; this action is probably mediated by enzymes of the caspase family and/or by granzyme B. The Fas/Fas1 system is also involved in apoptosis occurring in chronic non suppurative destructive cholangitis, in transplant rejection and in other liver diseases, including neoplasms; in the latter Bcl-2 protein and mutations of p53 also seem to play an important role. Cytokines are also frequently involved. Toxins like alcohol probably induce apoptosis by producing active oxidants. Whether aging enhances apopstosis in liver is still controversial. Although many molecular mechanisms have been suggested to be involved the switch on/off of apoptosis is still poorly understood and will be a matter of further investigations. Publication Types: Review Review, Tutorial PMID: 10091108 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 595: Pancreas. 1999 Mar;18(2):111-6. Utility of fluorescence in situ hybridization in pancreatic ductal adenocarcinoma. Adsay NV, Dergham ST, Koppitch FC, Dugan MC, Mohamed AN, Vaitkevicius VK, Sarkar FH. Department of Pathology, Wayne State University School of Medicine, Harper Hospital, and Karmanos Cancer Institute, Detroit, Michigan 48201, USA. Often the diagnosis of pancreas cancer needs to be established from limited cytology specimens or small biopsies. Most ductal adenocarcinomas are histologically well to moderately differentiated and mimicked closely by pancreatitis, and therefore the microscopic diagnosis can be difficult. In addition, there appears to be significant heterogeneity in the outcome of the patients with pancreatic cancer, which cannot be predicted accurately by current prognosticators such as the grade and stage of the tumor. Therefore, there is need for methods that can be used as adjuncts to routine diagnostic and prognostic parameters. This study was designed to test the utility of the fluorescent in situ hybridization (FISH) method in identifying the molecular alterations, particularly the ones that have been detected with relatively high frequency in pancreas cancer. Formalin-fixed and paraffin-embedded tissues of 10 cases were enumerated for chromosome 7, 8, 17, 18, and 20 copy numbers by using alpha-satellite probes, and for c-myc by using a gene-specific probe. The number of signals per nucleus (reflecting chromosomal copy number and status of c-myc amplification) were counted in more than two areas containing 50-500 cells. Because of tumor heterogeneity, monosomy (loss of one chromosome copy) was defined arbitrarily as one signal in >25% of nuclei. C-myc amplification was defined as more than two gene copies in >20% of the cells. The most frequent signal losses were found in chromosomes 8 (four of 10 cases) and chromosome 17 (four of 10), followed by 20 (three of 10) and 18 (two of 10). No loss of chromosome 7 was detected. In contrast, gains in chromosome copy number were identified in only one of 10 tumors, which showed gain of both chromosome 7 and 18. Amplification of c-myc gene was detected in two of 10 cases, but neither of the two had aneuploidy for chromosome 8, where the c-myc gene is located. In addition, loss in c-myc signal was observed in one case that also showed loss of chromosome 8 copy number. FISH can be used to detect chromosomal changes in pancreatic cancer; abundance of lytic enzymes in this organ is not an impediment for the applicability of this technique. Therefore it can potentially be used in the future as an adjunct to the conventional diagnostic and prognostic markers. This study confirms that loss of chromosomes, particularly chromosomes 17 and 18, which carry the p53 and DCC genes, are common in pancreas cancer. Chromosome 20 is also frequently lost. In addition, in this study, alterations of chromosome 8, which is seen commonly in prostatic adenocarcinoma but has not been previously documented in pancreatic cancer, also was detected in five of 10 tumors. Furthermore, amplification of the c-myc gene, which is located in chromosome 8, was found in the two of the remaining five cases. Further studies are needed to confirm this high incidence of chromosome 8 and c-myc alterations and their possible role in the pathogenesis of pancreatic adenocarcinoma. PMID: 10090407 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 596: J Comp Pathol. 1999 Feb;120(2):169-75. Immunohistochemical detection of p53 and c-myc proteins in canine mammary tumours. Inoue M, Shiramizu K. Department of Veterinary Pathology, Faculty of Agriculture, Yamaguchi University, Japan. The objectives of this study were to detect by immunohistochemical means, nuclear accumulations of p53 and c-myc proteins in mammary tumours of dogs. Moderate or intense p53 protein nuclear labelling was shown by each of five osteosarcomas. In contrast, focal immunoreactivity was shown by three of five adenocarcinomas and two of three malignant myoepitheliomas. Six benign mixed tumours and three myoepitheliomas showed no detectable immunoreactivity. On the other hand, three patterns of c-myc protein nuclear reactivity were observed in these tumours. Osteosarcomas, adenocarcinomas, malignant myoepitheliomas and myoepitheliomas showed intense or moderate reactivity. In benign mixed tumours, the epithelial component showed moderate or intense reactivity, and the myoepithelial component showed focal or moderate reactivity. These results demonstrated that p53 protein was expressed only in the osteosarcomas, but that c-myc expression was detectable in both the epithelial and myoepithelial components. PMID: 10087490 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 597: Jpn J Cancer Res. 1999 Jan;90(1):40-7. Analysis of the c-myc, K-ras and p53 genes in methylcholanthrene-induced mouse sarcomas. Watanabe H, Shimokado K, Asahara T, Dohi K, Niwa O. Second Department of Surgery, Hiroshima University School of Medicine. nabe3@hiroshima-cdas.or.jp We have examined 63 methylcholanthrene (MCA)-induced mouse sarcomas for possible correlations of mutations involving the c-myc, ras and p53 genes. The c-myc gene was found to be amplified in 18 of these sarcomas (29%). Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and subsequent direct sequencing identified 18 cases carrying K-ras mutation at codons 12, 13 and 61 (29%). No mutation was detected in the H-ras and N-ras genes. Mutations of the p53 gene in exons 5 to 8 were found in 45 cases (71%). Comparison of these mutations revealed that out of 18 cases with c-myc gene amplifications, 10 carried K-ras mutations (56%) and 14 carried p53 mutations (78%). In contrast, among 45 cases of sarcomas without c-myc gene amplification, 8 were found to have K-ras mutations (18%). The same 45 cases were found to have 31 p53 mutations (69%). The present study suggests a strong correlation between c-myc gene amplification and K-ras gene mutation (P < 0.01). p53 gene mutation was frequently found among MCA-induced mouse sarcomas, indicating the importance of this mutation in the etiology of these tumors. However, p53 mutations were present in sarcomas regardless of the state of c-myc amplification and K-ras mutation. Therefore, a defect in the p53 gene is independent of amplification of the c-myc gene or point mutation of the K-ras gene. PMID: 10076563 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 598: Mol Pharmacol. 1999 Mar;55(3):403-10. Induction of apoptosis by N-(4-hydroxyphenyl)retinamide and its association with reactive oxygen species, nuclear retinoic acid receptors, and apoptosis-related genes in human prostate carcinoma cells. Sun SY, Yue P, Lotan R. Department of Thoracic/Head and Neck Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston 77030, USA. ssun@notes.mdacc.tmx.edu The synthetic retinoid N-(4-hydroxyphenyl)retinamide (4HPR) has been shown to induce apoptosis in various malignant cells including human prostate carcinoma cells (HPC). We examined several possible mechanisms by which 4HPR could induce apoptosis in HPC cells. 4HPR exhibited concentration- and time-dependent decrease in cell number both in androgen-dependent (LNCaP) and -independent (DU145 and PC-3) cells. The 4HPR concentrations causing 50% decrease in cell number in LNCaP, DU145, and PC-3 cultures were 0.9 +/- 0.16, 4.4 +/- 0.45, and 3.0 +/- 1.0 microM, respectively, indicating that LNCaP cells were more sensitive to 4HPR than the other cells. 4HPR-induced apoptosis in all three cell lines was evidenced by increased enzymatic labeling of DNA breaks and formation of a DNA ladder. 4HPR increased the level of reactive oxygen species, especially in LNCaP cells. 4HPR-induced apoptosis could be suppressed in LNCaP cells by antioxidant and in DU145 cells by a nuclear retinoic acid receptor-specific antagonist, suggesting the involvement of reactive oxygen species or retinoic acid receptors in mediating apoptosis induced by 4HPR in the different HPC cells. Furthermore, 4HPR modulated the expression levels of some apoptosis-related gene (p21, c-myc, and c-jun), which may also contribute to the induction of apoptosis by 4HPR in HPC cells. PMID: 10051523 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 599: Oncogene. 1999 Feb 18;18(7):1479-86. MycN sensitizes neuroblastoma cells for drug-induced apoptosis. Fulda S, Lutz W, Schwab M, Debatin KM. University Children's Hospital, Ulm, Germany. Amplification of the MYCN gene is found in a large proportion of neuroblastoma and considered as an adverse prognostic factor. To investigate the effect of ectopic MycN expression on the susceptibility of neuroblastoma cells to cytotoxic drugs we used a human neuroblastoma cell line harboring tetracycline-controlled expression of MycN. Neither conditional expression of MycN alone nor low drug concentrations triggered apoptosis. However, when acting in concert, MycN and cytotoxic drugs efficiently induced cell death. Apoptosis depended on mitochondrial permeability transition and activation of caspases, since the mitochondrion-specific inhibitor bongkrekic acid and the caspase inhibitor zVAD-fmk almost completely abrogated apoptosis. Loss of mitochondrial transmembrane potential and release of cytochrome c from mitochondria preceded activation of caspase-8 and caspase-3 and cleavage of PARP. CD95 expression was upregulated by treatment with cytotoxic drugs, while MycN cooperated with cytotoxic drugs to increase sensitivity to CD95-induced apoptosis and enhancing CD95-L expression. MycN overexpression and cytotoxic drugs also synergized to induce p53 and Bax protein expression, while Bcl-2 and Bcl-X(L) protein levels remained unchanged. Since amplification of MYCN is usually associated with a poor prognosis, these findings suggest that dysfunctions in apoptosis pathways may be a mechanism by which MycN-induced apoptosis of neuroblastoma cells is inhibited. PMID: 10050884 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 600: Biochem Biophys Res Commun. 1999 Feb 24;255(3):722-30. Effects of wild-type and mutated p53 and Id proteins on the induction of apoptosis by adenovirus E1A, c-Myc, Bax, and Nip3 in p53 null mouse cerebellum cells. Tsunoda H, Terasawa T, Yageta M, Nakajima T, Tomooka Y, Tsuchida N, Oda K. Department of Biological Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda, 278, Japan. The sensitivities of apoptosis induced by E1A, c-Myc, Bax, and Nip3 to wild-type (wt) and mutated p53 and Id proteins were analyzed by transient transfection followed by flow cytometry with p53 null mouse cerebellum cell lines W7 and M13 that express wt and mutated p53 in response to dexamethasone, respectively. Apoptosis induced by c-Myc was stimulated weakly by wt p53, strongly by Ids, but suppressed completely by mutated p53 irrespective of coexpression with Ids, while apoptosis induced by E1A was suppressed by mutated p53 but stimulated when coexpressed with Ids. Apoptosis induced by Bax was little affected by wt and mutated p53, but inhibited by Ids, while apoptosis induced by Nip3 was inhibited by both wt and mutated p53 and inhibition was stimulated by Ids. Caspase-1 was activated only by Bax significantly when coexpressed with mutated p53 but not with wt p53. These results indicate that the apoptotic processes elicited by these inducers are different and differently affected by wt and mutated p53 and by Ids. Copyright 1999 Academic Press. PMID: 10049778 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 601: Clin Cancer Res. 1999 Feb;5(2):361-9. Expression of apoptosis-related genes in human head and neck squamous cell carcinomas undergoing p53-mediated programmed cell death. Frederick MJ, Holton PR, Hudson M, Wang M, Clayman GL. Department of Head and Neck Surgery, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA. Human head and neck squamous cell carcinoma (HNSCC) lines infected with a replication-defective Ad5CMV-p53 vector bearing a wild-type human p53 gene were used to examine alterations in the production of proteins implicated in regulating apoptosis. Because HNSCC lines express abundant levels of c-myc, and simultaneous expression of c-myc and p53 is known to trigger apoptosis in other cells, cooperation between these two genes was examined. Surprisingly, levels of c-myc mRNA and protein were rapidly and profoundly suppressed after infection with wild-type p53. Suppression of c-myc using antisense oligodeoxynucleotides (in the absence of p53) was sufficient to trigger apoptosis in Tu-138 cells, raising the possibility that the reduction of c-myc may be involved in at least one of the cell death pathways mediated by p53. Expression of a panel of Bcl-2 homology proteins was also examined in HNSCC lines undergoing p53-mediated apoptosis. No changes in Bcl-2, Bak, or Bcl-xS were found after p53 expression. Increased levels of the apoptosis-accelerating protein Bax were found in HNSCC lines after infection with Ad5CMV-p53. Induction of the apoptosis-inhibiting protein Bcl-xL was observed in Tu-167 cells and may account for the delayed onset of apoptosis in these cells. These studies suggest that multiple pathways may regulate apoptosis after transient overexpression of p53. PMID: 10037186 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 602: Rapid Commun Mass Spectrom. 1998;12(24):1986-93. Protein profiles and identification of high performance liquid chromatography isolated proteins of cancer cell lines using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Chong BE, Lubman DM, Rosenspire A, Miller F. Department of Chemistry, University of Michigan, Ann Arbor 48109-1055, USA. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has been used to rapidly profile the protein content of human cell lysates from MCF-10 cell and variant lines. The method was used to study the protein profiles of these cells as they progressed from normal breast epithelium to fully malignant cells. Distinct differences in the protein profiles were observed with progression, and specific proteins associated with carcinogenesis (p53, c-myc, and c-erbB-2) were heavily expressed in these cells as detected by MALDI-TOFMS. These proteins were also isolated using non-porous reversed-phase high performance liquid chromatography (NP-RP-HPLC) and mass analyzed by MALDI-TOFMS to provide molecular weight information without interference from other proteins in the whole cell lysates, and to avoid suppression effects in mixtures of proteins detected by MALDI-TOFMS. In order to confirm the identity of these oncoproteins, the cell lysates were subjected to one-dimensional (1-D) gel separation and subsequently electroblotted onto a poly(vinylidene difluoride) (PVDF) membrane for further analysis. Trypsin and cyanogen bromide digestions were performed on these proteins eluted from excised PVDF bands which were then analyzed by MALDI-TOFMS. The identity of these proteins was confirmed by database matching procedures. PMID: 10036781 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 603: Oncogene. 1998 Dec 31;17(26):3507-12. Mutant p53 can provoke apoptosis in p53-deficient Hep3B cells with delayed kinetics relative to wild-type p53. Stahler F, Roemer K. Department of Virology, University of Saarland Medical School, Homburg/Saar, Germany. Wild-type (wt) p53 frequently induces apoptosis when expressed in tumor cells whereas mutant p53 acts as an oncoprotein and consequently, stimulates cell proliferation. We report here exceptions to that rule. p53 conformational mutant 175H and DNA contact mutant 273H provoke apoptosis in human p53-deficient Hep3B hepatoma cells with delayed kinetics relative to wt p53. Similarly, c-Myc strongly stimulates apoptosis in these cells. In contrast, viral oncoproteins E1A and E7, and the cellular oncoprotein MDM-2, fail to elicit cytocidal responses. Efficient apoptotic cell death by mutant p53 requires oligomerization as 175H and 273H with deletions between amino acid residues 326 and 347 of the oligomerization domain are nontoxic. Apoptosis by mutant or wt p53 was significantly inhibited by the serine protease inhibitor AEBSF but not by the inactive analog AEBSA. Together, these results suggest that a wt p53-independent control mechanism is operational in Hep3B cells that eliminates cells upon sensing illegitimate proliferation signals originating from certain oncoproteins, including mutant p53 and Myc. We suggest that some tumor cell types lack p53 altogether because they tolerate neither wild-type nor mutant forms of the protein. PMID: 10030675 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 604: Bull Cancer. 1999 Jan;86(1):9-14. [Bright note on the molecular mechanisms of oncogenic transformation] [Article in French] Blanchard JM. Institut de genetique moleculaire, CNRS, UMR 5535, 1919, route de Mende, 34293 Montpellier Cedex 5. Publication Types: Review PMID: 10029698 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 605: Br J Cancer. 1999 Feb;79(3-4):393-400. Non-steroidal anti-inflammatory drug-induced apoptosis in gastric cancer cells is blocked by protein kinase C activation through inhibition of c-myc. Zhu GH, Wong BC, Eggo MC, Ching CK, Yuen ST, Chan EY, Lai KC, Lam SK. Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong. Apoptosis plays a major role in gastrointestinal epithelial cell turnover, ulcerogenesis and tumorigenesis. We have examined apoptosis induction by non-steroidal anti-inflammatory drugs (NSAIDs) in human gastric (AGS) cancer cells and the role of protein kinase C (PKC) and apoptosis-related oncogenes. After treatment with aspirin or indomethacin, cell growth was quantified by MTT assay, and apoptosis was determined by acridine orange staining, DNA fragmentation and flow cytometry. The mRNA and protein of p53, p21waf1/cip1 and c-myc was detected by Northern and Western blotting respectively. The influence of PKC on indomethacin-induced apoptosis was determined by co-incubation of 12-O-tetradecanoylphorbol 13-acetate (TPA). The role of c-myc was determined using its antisense oligonucleotides. The results showed that both aspirin and indomethacin inhibited cell growth and induced apoptosis of AGS cells in a dose- and time-dependent manner, without altering the cell cycle. Indomethacin increased c-myc mRNA and protein, whereas p53 and p21wafl/cip1 were unchanged. Down-regulation of c-myc by its antisense oligonucleotides reduced apoptosis induction by indomethacin. TPA could inhibit indomethacin-induced apoptosis and accumulate cells in G2/M. Overexpression of c-myc was inhibited by TPA and p21waf1/cip1 mRNA increased. In conclusion, NSAIDs induce apoptosis in gastric cancer cells which may be mediated by up-regulation of c-myc proto-oncogene. PKC activation can abrogate the effects of NSAIDs by decreasing c-myc expression. PMID: 10027304 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 606: Oncogene. 1999 Jan 28;18(4):1067-72. Estrogen-dependent and independent activation of the P1 promoter of the p53 gene in transiently transfected breast cancer cells. Hurd C, Dinda S, Khattree N, Moudgil VK. Department of Biological Sciences, Center for Biomedical Research, Oakland University, Rochester, Michigan 48309-4476, USA. Loss of p53 function by mutational inactivation is the most common marker of the cancerous phenotype. Previous studies from our laboratory have demonstrated 17 beta estradiol (E2) induction of p53 protein expression in breast cancer cells. Although direct effects of E2 on the expression of p53 gene are not known, the steroid is a potent regulator of c-Myc transcription. In the present studies, we have examined the ability of E2 and antiestrogens to regulate the P1 promoter of the p53 gene which contains a c-Myc responsive element. Estrogen receptor (ER)-positive T47D and MCF-7 cells were transiently transfected with the P1CAT reporter plasmid and levels of CAT activity in response to serum, E2 and antiestrogens were monitored. Factors in serum were noted to be the dominant inducers of chloramphenicol acetyltransferase (CAT) expression in MCF-7 cells. The levels of CAT were drastically reduced when cells were maintained in serum free medium (SFM). However, a subtle ER-mediated induction of CAT expression was detectable when MCF-7 cells, cultured in SFM, were treated with E2. In serum-stimulated T47D cells, the CAT expression was minimal. The full ER antagonist, ICI 182 780 (ICI) had no effect. Treatment with E2 or 4-hydroxy tamoxifen (OHT) resulted in P1CAT induction; OHT was more effective than E2. Consistent with c-Myc regulation of the P1 promoter, E2 stimulated endogenous c-Myc in both cell lines. Two forms of c-Myc were expressed independent of E2 stimuli. The expression of a third more rapidly migrating form was E2-dependent and ER-mediated since it was blocked by the full ER antagonist, ICI, but not by the ER agonist/antagonist OHT. These data demonstrate both ER-mediated and ER-independent regulation of c-Myc and the P1 promoter of the p53 gene, and show differential effects of the two classes of antiestrogens in their ability to induce the P1 promoter of the p53 gene in breast cancer cells. PMID: 10023683 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 607: Oncogene. 1999 Jan 28;18(4):1061-6. p73 at chromosome 1p36.3 is lost in advanced stage neuroblastoma but its mutation is infrequent. Ichimiya S, Nimura Y, Kageyama H, Takada N, Sunahara M, Shishikura T, Nakamura Y, Sakiyama S, Seki N, Ohira M, Kaneko Y, McKeon F, Caput D, Nakagawara A. Division of Biochemistry, Chiba Cancer Center Research Institute, Japan. p73, a novel p53 family member, is a recently identified candidate neuroblastoma (NBL) suppressor gene mapped at chromosome 1p36.33 and was found to inhibit growth and induce apoptosis in cell lines. To test the hypothesis that p73 is a NBL suppressor gene, we analysed the p73 gene in primary human NBLs. Loss of heterozygosity (LOH) for p73 was observed in 19% (28/151) of informative cases which included 92 mass-screening (MS) tumors. The high frequency of p73 LOH was significantly associated with sporadic NBLs (9% vs 34%, P<0.001), N-myc amplification (10% vs 71%, P<0.001), and advanced stage (14% vs 28%, P<0.05). Both p73alpha and p73beta transcripts were detectable in only 46 of 134 (34%) NBLs at low levels by RT-PCR methods, while they were easily detectable in most breast cancers and colorectal cancers under the same conditions. They found no correlation between p73 LOH and its expression levels (P>0.1). We found two mutations out of 140 NBLs, one somatic and one germline, which result in amino acid substitutions in the C-terminal region of p73 which may affect transactivation functions, though, in the same tumor samples, no mutation of the p53 gene was observed as reported previously. These results suggest that allelic loss of the p73 gene may be a later event in NBL tumorigenesis. However, p73 is infrequently mutated in primary NBLs and may hardly function as a tumor suppressor in a classic Knudson's manner. PMID: 10023682 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 608: Oncogene. 1999 Feb 4;18(5):1177-84. C-myc overexpression and p53 loss cooperate to promote genomic instability. Yin XY, Grove L, Datta NS, Long MW, Prochownik EV. Department of Pediatrics, Children's Hospital of Pittsburgh Pennsylvania, USA. p53 monitors genomic integrity at the G1 and G2/M cell cycle checkpoints. Cells lacking p53 may show gene amplification as well as the polyploidy or aneuploidy typical of many tumors. The pathways through which this develops, however, are not well defined. We demonstrate here that the combination of p53 inactivation and c-myc overexpression in diploid cells markedly accelerates the spontaneous development of tetraploidy. This is not seen with either N-myc or L-myc. Tetraploidy is accompanied by significantly higher levels of cyclin B and its associated cdc2 kinase activity. Mitotic spindle poisons accelerate the appearance of tetraploidy in cells either lacking functional p53 or overexpressing c-myc whereas the combination is additive. Restoration of p53 function in cells overexpressing c-myc causing rapid apoptosis, indicating that cells yet to become tetraploid have nonetheless suffered irreversible genomic and/or mitotic spindle damage. In the face of normal p53 function, such damage would either be repaired or trigger apoptotis. We propose that loss of p53 and overexpression of c-myc permits the emergence and survival of cells with increasingly severe damage and the eventual development of tetraploidy. PMID: 10022123 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 609: Postepy Biochem. 1998;44(3):228-36. [Regulation of thymidylate synthase gene expression] [Article in Polish] Dabrowska M. Zaklad Biochemii Komorki, Instytut Biologii Doswiadczalnej im. M. Nenckiego PAN, Warszawa. Publication Types: Review PMID: 10022042 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 610: Cancer Res. 1999 Feb 1;59(3):758-65. Focal adhesion kinase-dependent apoptosis of melanoma induced by tyrosine and phenylalanine deficiency. Fu YM, Yu ZX, Pelayo BA, Ferrans VJ, Meadows GG. Department of Pharmaceutical Sciences, College of Pharmacy, and the Cancer Prevention and Research Center, Washington State University, Pullman 99164-6510, USA. We found previously that restriction of tyrosine (Tyr) and phenylalanine (Phe) inhibited growth and metastasis of B16BL6 murine melanoma and arrested these cells in the G0-G1 phase of the cell cycle. Here, we report that deprivation of these two amino acids in vitro induces apoptosis in B16BL6 and in human A375 melanoma cells but not in nontransformed, neonatal murine epidermal cells or human infant foreskin fibroblasts. Four days after deprivation of Tyr and Phe in vitro, 37% of B16BL6 and 51% of A375 melanoma cells were undergoing apoptosis. Apoptosis was not associated with elevation in intracellular calcium or alteration in p53 or c-myc protein expression. Expression and Tyr phosphorylation of focal adhesion kinase (FAK) were inhibited in both melanoma cell lines by deprivation of Tyr and Phe but not by deprivation of glutamine or serum. Tyr phosphorylation of FAK in Tyr- and Phe-deprived melanoma cells was enhanced within 30 min of refeeding with complete DMEM. FAK protein expression recovered within 60 min, and cell viability recovered within 24 h. Genistein, a tyrosine kinase inhibitor that specifically inhibits Tyr phosphorylation of FAK, did not induce apoptosis in A375 melanoma cells at a concentration of 50 microM. Genistein prevented the recovery of cell viability upon refeeding with Tyr and Phe to previously deprived A375 melanoma cells. These data collectively indicate that apoptosis induced by Tyr and Phe deprivation is FAK-dependent. PMID: 9973229 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 611: Invest Clin. 1998 Dec;39(4):323-58. [Molecular bases of the programmed cell death process: implications of tumor suppressor protein p53 and other proteins in the control of cell cycle. Mechanisms of apoptotic action. Review] [Article in Spanish] Merino JJ, Cordero-Campana MI. Departamento de Psicobiologia, Universidad Nacional de Educacion a Distancia, Madrid, Espana. Apoptosis is a mechanism of cell death that occurs in normal development and on the regulation of vertebrate tissues and organ cellularity. Neurons undergo p53-dependent and p53-independent apoptosis, depending upon the stimulus that triggers DNA fragmentation. Many neurons in the developing nervous system suffer apoptosis, with the cyclin D1 being an essential mediator of neuronal cell death. Other characteristics of apoptosis are: condensation of the nucleus, fragmentation of chromatin at nucleosome linkage sites, membrane blebbing, and the formation of apoptotic bodies. Among the possible molecular mechanisms are: (a) activation of proteases, as ICE (Il-1 beta converting enzyme); (b) calpain is activated in several cells, with PARP (Poly-ADP-ribose polymerase) and a small U1 Ribonucleoprotein, being substrates for ICE and its homologs such as ICH and others proteins. The p53 gene encodes a transcription factor that contributes to several different cellular activities, including apoptosis, the cellular response to radiation, and the activation of proteins such as GADD, Bcl-2 (represses to apoptosis) and Bax. P53 exerts a role as inductor of apoptosis by transactivating expression of the Bax gene. The p53 gene tumor suppressor limits cellular proliferation by including either the arrest of cell cycle in G1, or apoptosis, depending on the cellular context. The p21 is an inhibitor of cyclin-dependent kinase, which is transactivated by p53. During apoptosis, there is an activation of both, c-myc, and the transcription factor NF-kB, which is a important regulator of apoptosis. As an example of signalization of apoptosis we have selected to illustrate the problem related to the system Fas/APO in thymocytes. Publication Types: Review Review, Tutorial PMID: 9927805 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 612: Oncogene. 1999 Jan 14;18(2):439-48. Apoptosis-prone phenotype of human colon carcinoma cells with a high level amplification of the c-myc gene. Donzelli M, Bernardi R, Negri C, Prosperi E, Padovan L, Lavialle C, Brison O, Scovassi AI. Istituto di Genetica Biochimica ed Evoluzionistica CNR, Pavia, Italy. Although apoptosis can be induced by the enforced expression of exogenously introduced c-myc genes, it is not clear whether overexpression resulting from the amplification of the resident c-myc gene in tumor cells is sufficient to induce apoptosis. We have investigated the relationship between c-myc gene amplification and the propensity of tumor cells to undergo apoptosis, using the SW613-12A1 and SW613-B3 cell lines, which are representatives, respectively, of tumorigenic and non-tumorigenic clones isolated from the SW613-S human colon carcinoma cell line. Tumorigenic clones are characterized by a high level of amplification and expression of the c-myc gene, whereas cells of non-tumorigenic clones have a small number of copies and a lower level of expression of this gene. Analysis of c-myc mRNA level in cells cultured under low serum conditions indicated that the expression of the gene is tightly regulated by serum growth factors in non-tumorigenic B3 cells, whereas it is poorly regulated in tumorigenic 12A1 cells, the level of mRNAs remaining relatively high in serum-starved 12A1 cells. Under these conditions, 12A1 cells showed clear evidence of apoptosis, whereas B3 cells were completely refractory to the induction of apoptosis. Moreover, the study of cell lines derived from non-tumorigenic apoptosis-resistant clones following the introduction by transfection of exogenous c-myc gene copies showed that they have acquired an apoptosisprone phenotype. Altogether, our results strongly suggest that deregulated c-myc expression due to high-level amplification confers an apoptosis-prone phenotype to tumor cells. The possible consequences of these observations for cancer therapy are discussed. PMID: 9927200 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 613: J Pathol. 1998 Oct;186(2):209-14. Tumours derived from HTLV-I tax transgenic mice are characterized by enhanced levels of apoptosis and oncogene expression. Hall AP, Irvine J, Blyth K, Cameron ER, Onions DE, Campbell ME. Department of Veterinary Pathology, Glasgow University Veterinary School, U.K. In order to investigate the role that the human T-lymphotropic virus type I (HTLV-I) tax oncogene plays in apoptosis and transformation in vivo, four lines of HTLV-I tax transgenic mice were generated under the regulatory control of the CD3-epsilon promoter-enhancer sequence. These mice develop a variety of phenotypes including mesenchymal tumours, which develop at wound sites, and salivary and mammary adenomas. In situ DNA fragment labelling and immunocytochemical analysis of these tumours reveals that they display enhanced levels of apoptosis, which is associated with elevated levels of Myc, Fos, Jun, and p53 protein expression. Furthermore, double immunofluorescent staining shows that Tax expression and apoptosis co-localize, indicating that Tax expression is closely associated with apoptosis in vivo. PMID: 9924438 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 614: Anticancer Res. 1998 Nov-Dec;18(6A):4003-10. Growth inhibition and activation of apoptotic gene expression by human chorionic gonadotropin in human breast epithelial cells. Srivastava P, Russo J, Mgbonyebi OP, Russo IH. Breast Cancer Research Laboratory, Fox Chase Cancer Center Philadelphia, PA 19111, USA. The glycoprotein hormone, human chorionic gonadotropin (hCG) inhibits mammary tumorigenesis through induction of differentiation, and inhibits the proliferation of human breast epithelial cells (HBEC) in vitro. The present study was designed to determine whether the inhibitory effects of hCG was associated with the modulation of apoptotic gene expression. MCF-10F, a normal immortalized HBEC, BP1-E, a benzo(a)pyrene (BP) transformed cell line, and the urothelial cell line T24, were treated with 100 IU/ml of a commercially available preparation of hCG. Cell growth analysis and RNA extraction for determination of apoptotic gene expression were performed at 24 and 120 hrs of hCG treatment. Both hCG-treated and control cells grew at similar rates for the first 24 hours. A significant reduction in the number of viable MCF-10F and BP1-E cells occurred by 120 hours of treatment, whereas the number of both hCG treated and control T24 cells were similar. Northern blot analysis revealed that the 24 hour-hCG treatment induced an elevation in the expression of the apoptotic genes TRPM2, ICE, TGF-beta, p53, bax, and p21WAF1/CIP1 in MCF-10F cells. By 120 hours of treatment MCF-10F cells maintained the same level of gene expression observed at 24 hours, except for a reduction in c-myc and bax. Control cells exhibited an elevation in the expression of TRPM2, TGF-beta, p53, bax, and p21WAF1/CIP1, whose levels became similar to those observed in hCG-treated cells. The 24 hour-treated BP1-E cells showed activation of ICE, bax and p21WAF1/CIP1. However, TRPM2 expression was moderately activated. By 120 hours TRPM2, ICE, TGF-beta, c-myc and p21WAF1/CIP1 were elevated in both treated and control cells except bax which was slightly down-regulated. The levels of bc12 were significantly decreased by hCG treatment. Gene expression was not modified by hCG treatment in T24 cells. Our findings suggest that hCG induced an acceleration in the expression of apoptotic genes, which became evident before detection of cell growth inhibition. Gene activation differed among immortalized, and chemically transformed cells, suggesting that hCG might utilize both p53 dependent and p53 independent pathways for inhibiting cell cycle progression. The importance of these findings lies in the potential use of agents like hCG for the chemoprevention and chemotherapy of breast cancer. PMID: 9891438 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 615: Brain Res Mol Brain Res. 1999 Jan 22;64(1):59-68. Free radical scavenger OPC-14117 attenuates quinolinic acid-induced NF-kappaB activation and apoptosis in rat striatum. Nakai M, Qin ZH, Wang Y, Chase TN. Experimental Therapeutics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bldg 10, Rm. 5C103, 10 Center Drive, MSC 1406, Bethesda, MD 20892-1406, USA. Oxidative stress has long been implicated in the pathogenesis of both the acute and chronic neurotoxic effects of glutamate acting through ionotrophic receptors of the N-methyl-d-aspartate (NMDA) subtype. To evaluate the contribution of oxidative stress to the NMDA receptor-mediated apoptotic death of rat striatal neurons in vivo, the effects of a novel, orally administered free radical scavenger, OPC-14117, was studied following intrastriatal infusion of the NMDA receptor agonist quinolinic acid (QA). Receptor autoradiography and in situ hybridization histochemistry showed that pretreatment with OPC-14117 (600 mg/kg) reduced the QA (120 nmol)-induced loss of striatal D1 dopamine receptors by about 20% (p<0.01) and NMDA receptors by 15% (p<0.01) as well as 67 kDa glutamic acid decarboxylase mRNA (34%; p<0.01) and proenkephalin mRNA (36%; p<0.01). OPC-14117 also decreased the apomorphine-induced ipsilateral rotational response in unilaterally QA-lesioned animals by about 70% (p<0.05). In addition, OPC-14117 pretreatment inhibited QA-induced internucleosomal DNA fragmentation. Western blot analysis and electrophoresis mobility shift assay further revealed that the free radical scavenger (300 and 600 mg/kg) blunted the QA-induced degradation of IkappaBalpha (increased IkappaBalpha levels from about 15% to 33 and 62% of control, respectively; p<0.01) as well as the ensuing activation of NF-kappaB by 25 to 34%, respectively (p<0. 01) and the augmentation in c-Myc (35 to 70%, respectively) and p53 expression by 50-80%, respectively (both p<0.01). In contrast, OPC-14117 had no significant effect on the QA-induced increase in AP-1 binding activity. These results suggest that the NMDA receptor-mediated generation of reactive oxygen species contributes to the QA-induced activation of NF-kappaB and further that orally administered OPC-14117 partially protects against excitotoxin-induced apoptosis of striatal neurons through inhibition of the NF-kappaB apoptotic cascade. Copyright 1999 Elsevier Science B.V. PMID: 9889320 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 616: Mod Pathol. 1998 Dec;11(12):1228-37. Establishment and molecular characterization of five cell lines derived from renal and extrarenal malignant rhabdoid tumors. Rosson GB, Hazen-Martin DJ, Biegel JA, Willingham MC, Garvin AJ, Oswald BW, Wainwright L, Brownlee NA, Wright CF. Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston 29425, USA. Malignant rhabdoid tumor (MRT) is a rare, enigmatic childhood cancer characterized by extreme aggressiveness and resistance to chemotherapy. To understand better the origin of the tumor and the mechanisms by which it develops and resists treatment, five cell lines were established from patients presenting with MRT (two renal and three extrarenal tumors). All of the cell lines display the light microscopic and ultrastructural features, as well as the variable immunohistochemical profile, characteristic of MRT. All are capable of forming tumors in nude mice. Three of the cell lines have detectable abnormalities of chromosome 22: one a t(22, 22) unbalanced translocation and two others a loss of heterozygosity of polymerase chain reaction-based microsatellite markers. Northern blot analysis showed that overexpression of the c-myc message was a consistent characteristic of the five MRTs evaluated. Although mutations of the p53 gene were not detectable by sequence analysis, all of the cell lines showed nuclear accumulation of the p53 protein by an immunocytochemical analysis in a minority of the cells. This result suggests that dysfunction in a p53-dependent apoptotic pathway might play a role in the multiple drug resistance phenotype of these tumors. Publication Types: Case Reports PMID: 9872656 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 617: Genes Dev. 1998 Dec 15;12(24):3803-8. Transactivation-defective c-MycS retains the ability to regulate proliferation and apoptosis. Xiao Q, Claassen G, Shi J, Adachi S, Sedivy J, Hann SR. Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2175 USA. Transcriptional activation by c-Myc through specific E box elements is thought to be essential for its biological role. However, c-MycS is unable to activate transcription through these elements and yet retains the ability to stimulate proliferation, induce anchorage-independent growth, and induce apoptosis. In addition, c-MycS retains the ability to repress transcription of several specific promoters. Furthermore, c-MycS can rescue the c-myc null phenotype in fibroblasts with homozygous deletion of c-myc. Taken together, our data argue against the paradigm that all of the biological functions of c-Myc are mediated by transcriptional activation of specific target genes through E box elements. PMID: 9869633 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 618: Genes Dev. 1998 Dec 15;12(24):3797-802. c-myc null cells misregulate cad and gadd45 but not other proposed c-Myc targets. Bush A, Mateyak M, Dugan K, Obaya A, Adachi S, Sedivy J, Cole M. Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544 USA. We report here that the expression of virtually all proposed c-Myc target genes is unchanged in cells containing a homozygous null deletion of c-myc. Two noteworthy exceptions are the gene cad, which has reduced log phase expression and serum induction in c-myc null cells, and the growth arrest gene gadd45, which is derepressed by c-myc knockout. Thus, cad and gadd45 are the only proposed targets of c-Myc that may contribute to the dramatic slow growth phenotype of c-myc null cells. Our results demonstrate that a loss-of-function approach is critical for the evaluation of potential c-Myc target genes. PMID: 9869632 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 619: Lung Cancer. 1998 Oct;22(1):1-13. Higher spontaneous apoptotic index in small cell compared with non-small cell lung carcinoma cell lines; lack of correlation with Bcl-2/Bax. Sirzen F, Zhivotovsky B, Nilsson A, Bergh J, Lewensohn R. Department of Oncology, Radiumhemmet, Karolinska Hospital, Stockholm, Sweden. Spontaneous apoptosis was assessed in ten small-cell (SCLC) and five non-small cell (NSCLC) lung carcinoma cell lines by the TUNEL assay and chromatin cleavage. TUNEL staining showed significantly higher apoptotic index (AI) in SCLC (2-20%) compared with NSCLC lines (0.2-1%) in untreated exponentially growing cells. Six out of ten SCLC and none of the NSCLC showed DNA fragmentation when analysed by agarose gel electrophoresis. Field inversion pulse gel electrophoresis was used in a subset of cell lines and showed the presence of high molecular weight fragments in untreated SCLC lines U-1285 and U-1906 cells, but not in the NSCLC line U-1810. Important molecular determinants of apoptosis were studied by Western blot. Bcl-2 was detected at highest level in SCLC. There was no correlation between the ratio Bcl-2/Bax and AI in all tested cell lines. Neither p53 nor c-Myc protein status correlated to AI. Pro-caspase-3 was expressed in all cell lines without correlation to AI and no difference between the SCLC and NSCLC groups was found. In conclusion, this study shows a high degree of spontaneous apoptosis in SCLC lines compared to NSCLC lines unrelated to Bcl-2/Bax ratio. PMID: 9869102 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 620: Eur J Histochem. 1997;41 Suppl 2:19-20. Monoclonal gammopathies with a high MC elicit altered phenotypic and genotypic features. Greco C, Alvino S, Mosiello A, Avilii G, Mattei F, Francavilla V, Valente F, Del Monte G, Cianciulli AM, Gandolfo GM. Dipt. Patalogia Clinica, Istituto Nazionale dei Tumori, Roma, Italy. PMID: 9859764 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 621: Int J Mol Med. 1998 Jun;1(6):953-9. Molecular correlates of bcl-2-enhanced growth following androgen-ablation in prostate carcinoma cells in vivo. Beham AW, Sarkiss M, Brisbay S, Tu SM, von Eschenbach AC, McDonnell TJ. Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA. Androgen-independent growth of prostate cancer is correlated with expression of bcl-2. The impact of bcl-2 expression on the growth of prostate cancer cells following androgen ablation, was examined in the androgen-sensitive prostatic carcinoma cell line, LNCaP. Vector control and bcl-2 expressing LNCaP cells were grown subcutaneously in male nude mice. Tumor volume, apoptosis, and proliferation were assessed following castration. The levels of c-myc, p53, p21, bax, and bcl-2 protein were assessed by Western blotting. Bcl-2 expressing tumors exhibited a significant augmentation in growth compared to controls (p 0.01). No difference in the spontaneous rate of proliferation was observed between bcl-2 and control tumors, however, bcl-2 expressing tumors exhibited lower rates of apoptosis. Following orchiectomy the apoptotic index remained significantly lower in bcl-2 expressing tumors (p 0.002 at day 3). The proliferative index was maintained in bcl-2 expressing, but not control tumors following castration. This resulted in a significant growth advantage in bcl-2 tumors subsequent to androgen ablation (p 0.001). These changes were accompanied by alterations in the levels of gene products known to regulate the cell cycle and/or apoptosis. These results emphasize the significance of bcl-2 expression during prostate cancer progression and suggest possible mechanisms for the acquisition of androgen-independent tumor growth. PMID: 9852630 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 622: Eur J Cancer. 1998 Jul;34(8):1268-73. bcl-2 expression is reciprocal to p53 and c-myc expression in metastatic human colorectal cancer. Popescu RA, Lohri A, de Kant E, Thiede C, Reuter J, Herrmann R, Rochlitz CF. Division of Oncology, Kantonsspital Basle, Switzerland. Apoptosis (programmed cell death) inhibition may be an important mechanism by which gastrointestinal mucosal cells containing damaged DNA evade normal clearance mechanisms and grow to become invasive tumours. Since bcl-2 is an apoptosis inhibitor, bcl-2 mRNA expression was measured in 21 metastases of colorectal cancer using reverse transcription-polymerase chain reaction analysis. The mean bcl-2 mRNA expression (0.45 U, P < 0.0001) was lower than that of normal mucosal controls (= 1 U). p53 expression was inversely correlated with bcl-2 expression (P = 0.021) in 19 evaluable samples, and in tumours where p53 expression was over twice that of normal colonic mucosal values, bcl-2 mRNA was significantly decreased (mean 0.30, P = 0.0052). c-myc was also inversely correlated with bcl-2 expression (P = 0.025). Decreased bcl-2 expression in metastatic colorectal cancer may be partly due to allelic loss, given the proximity of bcl-2 to the frequently deleted DCC gene on chromosome 18q. However, the inverse correlation to p53/c-myc suggests an active downregulation of bcl-2, possibly following delegation of its apoptosis inhibiting role to other genes. PMID: 9849490 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 623: Cancer Genet Cytogenet. 1998 Dec;107(2):137-43. 5' region and exon 7 mutations of the TP53 gene in two cases of B-cell prolymphocytic leukemia. De Angeli C, Cuneo A, Aguiari G, Roberti MG, Piva N, Moretti S, Cavazzini P, Castoldi G, del Senno L. Centro Interdipartimentale di Biotecnologie-Sezione di Studi Biochimici delle Patologie del Genoma Umano, Universita degli Studi, Ferrara, Italy. We previously found that cases of typical B-chronic lymphocytic leukemia (CLL), atypical B-CLL with t(11;14) and mantle cell lymphomas characterized by rapid progression of the disease and resistance to therapy, had mutations of the TP53 gene. In this paper, abnormalities of the TP53 gene were investigated in two cases of prolymphocytic leukemia, one with t(11;14)(q13;q32), evolving from atypical CLL (patient 1), and one presenting as a de novo condition (patient 2). TP53 DNA was investigated by Southern blot and PCR-SSCP analysis, and TP53 expression was investigated by Northern blot analysis and immunocytochemistry. C-MYC and BCL-1/PRAD1 gene expression were also investigated. Restriction enzyme analysis of TP53 DNA in patient 1 showed alteration of fragments including exon I and intron I, and, in both patients, a specific loss of TP53 DNA. In patient 2, PCR direct sequencing showed in exon VII a 9 bp deletion including codons 252-254. In patient 1, TP53 RNA and protein were not found, indicating that the unusual 5' rearrangement has affected TP53 gene expression. By contrast, patient 2 exhibited detectable TP53 RNA and protein. Detectable but weak BCL-1/PRAD1 RNA was present in both patients, whereas C-MYC RNA expression was clearly present only in case 1. The presence of TP53 hemizygous mutations in both patients suggests that TP53 abnormalities may be important in the pathogenesis of prolymphocytic leukemia (PLL), and may possibly account for the frequent resistance to therapy observed in this disease. Publication Types: Case Reports PMID: 9844609 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 624: Mol Immunol. 1998 Sep;35(13):829-35. Repression of the minimal HLA-B promoter by c-myc and p53 occurs through independent mechanisms. Griffioen M, Steegenga WT, Ouwerkerk IJ, Peltenburg LT, Jochemsen AG, Schrier PI. Department of Clinical Oncology, Leiden University Medical Center, The Netherlands. Major Histocompatibility Complex (MHC, HLA in humans) class I antigens play an important role in cellular immunology by presenting antigens to T cells. Downregulation of MHC class I expression is thought to be a mechanism by which tumor cells escape from T cell-mediated lysis. In primary human melanomas and melanoma cell lines, HLA-B expression is frequently downmodulated, correlating with elevated expression of the c-myc oncogene. Transfection experiments have shown that c-myc induces HLA-B downregulation through a -68 to +13 base pairs (bp) core promoter fragment, containing CCAAT and TATA-like (TCTA) boxes. Since (i) c-myc has been reported to activate the human p53 promoter and (ii) p53 is capable of repressing a large array of basal promoters, we investigated whether c-myc-induced HLA-B abrogation is mediated by p53. In this article, it is shown that the HLA-B core promoter is indeed repressed by wild-type p53, making p53 a candidate for mediating c-myc-induced HLA-B downregulation. However, transfection of c-myc into p53-null cell lines still resulted in suppression of the basal HLA-B promoter, demonstrating that c-myc and p53 repress the minimal HLA-B promoter through independent mechanisms. PMID: 9839551 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 625: Jpn J Clin Oncol. 1998 Oct;28(10):631-7. Astrocytoma and B-cell lymphoma development in a man with a p53 germline mutation. Murakawa Y, Yokoyama A, Kato S, Yoshioka T, Ichinohasama R, Kumabe T, Yoshimoto T, Ishioka C, Kanamaru R. Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan. We report a case with a germline mutation of the p53 gene develpoing both a non-Hodgkin's lymphoma and an astrocytoma. The astrocytoma could be cured by two operations and combined chemotherapy but 33 months after the onset of the disease, he suffered from a diffuse, large cell centroblastic malignant lymphoma of B-cell lineage. In spite of clear rearranged fragments observed with IgH and c-MYC gene probes, we could not diagnose a Burkitt's lymphoma morphologically. The malignant lymphoma was chemoresistant and the patient died of multi-organ failure. He was confirmed to have a germline mutation of the p53 gene by analysis of c-DNA from peripheral lymphocytes and loss of heterozygosity (LOH) of p53 was evident in the lymphoma. The results were suggestive of the Li-Fraumeni syndrome (LFS), a rare autosomal dominantly inherited syndrome with a germline mutation of p53 gene and diverse malignancies, but this could not be confirmed in the present case. Alternatively, a de novo mutation could have been involved. Publication Types: Case Reports PMID: 9839505 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 626: In Vivo. 1998 Sep-Oct;12(5):489-94. In vivo effects of CHOP protocol on onco and suppressor gene expression: follow-up study. Ember I, Kiss I, Raposa T, Nowrasteh G, Matolcsy A. Department of Preventive Medicine, University Medical School of Pecs, Hungary. In vivo investigation of onco/suppressor gene effects may provide new findings concerning chemical carcinogenesis. In earlier studies we pointed out the carcinogenic potential of COPP and ABVD chemotherapeutical protocols in "long-term" experiments. In another follow up study we proved the connection between the early gene expression changes and the late consequences of COPP and ABVD treatment during, a one year latency period. CHOP protocol is containing both proved carcinogenic cyclophosphamide and highly mutagenic doxorubicyn. CHOP protocol in "short-term" experiments shows strong effect on Ha-ras oncogene expression. PMID: 9827356 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 627: Scand J Immunol. 1998 Nov;48(5):551-6. Differential oncogene and TNF-alpha mRNA expression in bone marrow cells from systemic lupus erythematosus patients. Alvarado-de la Barrera C, Alcocer-Varela J, Richaud-Patin Y, Alarcon-Segovia D, Llorente L. Department of Immunology and Rheumatology, Instituto Nacional de la Nutricion Salvador Zubiran, Tlalpan, Mexico. The aim of the study was to investigate the bone marrow expression of genes involved in cell growth and apoptosis in patients with systemic lupus erythematosus (SLE). Spontaneous expression of bcl-2, bax, c-myc. c-fos, c-jun, p53, Fas and tumour necrosis factor (TNF)-alpha by bone marrow cells was measured using either semiquantitative or quantitative reverse transcription polymerase chain reaction in SLE patients (n = 8) and in eight normal control subjects. The expression of bcl-2 was found to be higher in SLE patients than in controls. Bone marrow cells from SLE patients showed significant down-regulation of bax, c-myc, c-fos and p53 (P < or = 0.05), as compared to normal controls. In both SLE patients and controls the expression of c-jun and Fas was very low or undetectable. Finally, TNF-alpha gene expression was higher in bone marrow samples from SLE patients than in those of controls (P= 0.01). The abnormal expression of genes regulating cell growth and apoptosis in bone marrow cells from SLE patients may help explain the presence of autoreactive cells in secondary lymphoid organs and peripheral blood of SLE patients. PMID: 9822266 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 628: Biol Chem. 1998 Oct;379(10):1253-61. Potentiation of 2-chlorodeoxyadenosine activity by bryostatin 1 in the resistant chronic lymphocytic leukemia cell line (WSU-CLL): association with increased ratios of dCK/5'-NT and Bax/Bcl-2. Mohammad RM, Beck FW, Katato K, Hamdy N, Wall N, Al-Katib A. Department of Medicine, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA. The activities of 2-chlorodeoxyadenosine (2-CdA) metabolizing enzymes, deoxycytidine kinase (dCK) and cytosolic 5'-nucleotidase (5'-NT) were measured in control and bryostatin 1 treated CLL cells using an EBV-negative WSU-CLL cell line. This cell line was established from a patient with CLL resistant to fludarabine. The results revealed a significant increase in dCK activity in bryostatin 1 treated cells at 48 and 72 h compared with the control. 5'-NT activity decreased significantly at 48 h. The ratio of dCK to 5'-NT activity was significantly increased in bryostatin 1 treated WSU-CLL cells after 48 h. WSU-CLL cells treated with bryostatin 1 exhibited an increase in the percentage of apoptotic and dead cells from control levels of 16% to 40%. This percentage was further increased to 67% following the addition of 11.2 microM 2-CdA to WSU-CLL cells pretreated with bryostatin 1. Results from Western blot analysis indicate that WSU-CLL cells express high levels of Bcl-2, Bcl-xL and c-myc, and a low level of Bax. p53 in untreated WSU-CLL cells is undetectable. WSU-CLL cells treated with bryostatin 1 showed a significant increase in the ratio of Bax to Bcl-2. To demonstrate that the bryostatin 1 mediated enhancement of 2-CdA efficacy was not restricted to in vitro cell culture, we have studied the tumor growth delay of WSU-CLL xenografts treated with placebo, bryostatin 1, 2-CdA, and bryostatin 1 followed by 2-CdA. SCID mice given bryostatin 1 at 75 microg x kg(-1) x d(-1) for 5 days followed by 30 mg x kg(-1) x d(-1) 2-CdA for 5 days in two cycles, had significantly improved tumor growth delay (P = 0.05). We conclude that bryostatin 1 is not only capable of inducing apoptosis by itself, but also sensitizes de novo resistant WSU-CLL cells to the chemo-therapeutic effects of 2-CdA. The bryostatin 1-induced increased ratio of dCK/5'-NT activity and an increased ratio of Bax/Bcl-2 are at least two mechanisms through which this natural compound is able to potentiate the anti-tumor activity of 2-CdA in otherwise resistant CLL cells. PMID: 9820586 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 629: Clin Cancer Res. 1996 Jun;2(6):1049-53. Overexpression of the c-myc proto-oncogene in colorectal carcinoma is associated with a reduced mortality that is abrogated by point mutation of the p53 tumor suppressor gene. Smith DR, Goh HS. Colorectal Cancer Research Laboratory, Department of Colorectal Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Republic of Singapore. The survival of 119 colorectal cancer patients was analyzed in the light of the overexpression status of the c-myc proto-oncogene mRNA and the point mutation status of the p53 tumor suppressor gene in the primary adenocarcinoma. The presence of >3 fold overexpression of c-myc mRNA in the primary tumor was found to be associated with a better prognosis than patients who evinced no overexpression (P = 0.02, log rank analysis). Point mutation of the p53 tumor suppressor gene was found to be associated with a poorer patient prognosis (P = 0.007, log rank analysis). Endogenous levels of c-myc and point mutation of p53 both contributed independently toward a poorer patient prognosis in Cox regression modeling. The better prognosis seen in patients who overexpress c-myc was offset when c-myc overexpression was coupled with a point mutated p53 gene. These results suggest that in colorectal adenocarcinoma c-myc deregulation leads to increased apoptotic death, but that this response may be modulated by a more downstream event such as point mutation of the p53 gene. PMID: 9816266 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 630: Virchows Arch. 1998 Oct;433(4):315-21. No correlation of c-myc overexpression and p53 mutations in liposarcomas. Schneider-Stock R, Walter H, Rys J, Radig K, Hoang-Vu C, Roessner A. Department of Pathology, Otto-von-Guericke University, Magdeburg, Germany. Regine.Schneider-Stock@medizin.uni-magdeburg.de Although it is well known that oncogenesis is a multistep process involving the activation of normal cellular genes to become oncogenes and/or the inactivation of tumor suppressor genes, this process has seldom been investigated in soft tissue tumours. We screened a group of 36 liposarcomas for genetic abnormalities in the p53 tumour suppressor gene and c-myc oncogene. Altered c-myc gene expression was examined by differential RT-PCR assay. p53 Gene mutations in exons 4-8 were analysed by using PCR-SSCP analysis and direct sequencing. Elevated c-myc expression was found in 6 of 31 liposarcomas (19.4%). p53 Gene mutations were observed in 5 of 36 liposarcomas (13.9%). Both genetic alterations were associated with the histological subtype of liposarcomas. Whereas c-myc gene expression was a characteristic of myxoid/round cell liposarcomas, p53 gene mutations were found more frequently in pleomorphic variants. Liposarcomas of the well-differentiated subtype showed neither p53 gene mutations nor altered c-myc gene expression. Our results indicate that the c-myc oncogene and the p53 tumor suppressor gene do not seem to cooperate in the oncogenesis of liposarcomas. PMID: 9808433 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 631: Oncogene. 1998 Oct 22;17(16):2115-23. p53-independent apoptotic effects of the hepatitis B virus HBx protein in vivo and in vitro. Terradillos O, Pollicino T, Lecoeur H, Tripodi M, Gougeon ML, Tiollais P, Buendia MA. Unite de Recombinaison et Expression Genetique (INSERM U163), Paris, France. The hepatitis B virus protein HBx is a promiscuous transactivator implicated in both cell growth and death and in the development of hepatocellular carcinoma. We recently reported that HBx can potentiate c-myc-induced liver oncogenesis in a transgenic model where low level expression of HBx induces no pathology. To assess if HBx could affect the hepatocyte turnover, we investigated the HBx-elicited apoptotic responses in transgenic livers and in primary hepatocyte cultures. Here we show that transgenic expression of HBx is associated with a twofold increase of spontaneous cell death in the mouse liver. The finding that apoptosis was enhanced to similar extents in HBx mice carrying homozygous p53 null mutations implied that functionally intact p53 was not required to transduce the death signal. A direct, dose-dependent apoptotic function of HBx was demonstrated in transient transfections of liver-derived cell lines. We further show that stable expression of HBx at low, presumably physiological levels in primary hepatocytes, induced cellular susceptibility to diverse apoptotic insults, including growth factor deprivation, treatment with anti-Fas antibodies or doxorubicine and oxidative stress. HBx expression, but not p53 status profoundly affected the commitment of cells to die upon apoptotic stimuli. These data strengthen the notion that HBX may contribute to HBV pathogenesis by enhancing apoptotic death in the chronically infected liver. PMID: 9798683 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 632: Oncogene. 1998 Sep 24;17(12):1577-85. Expression of T:G mismatch-specific thymidine-DNA glycosylase and DNA methyl transferase genes during development and tumorigenesis. Niederreither K, Harbers M, Chambon P, Dolle P. Institut de Genetique et de Biologie Moleculaire et Cellulaire, CNRS/INSERM/ULP/College de France, Illkirch, C.U. de Strasbourg. In situ hybridization was used to characterize the expression pattern of the T:G mismatch-specific thymidine-DNA glycosylase (TDG) gene, encoding a DNA repair enzyme which corrects G:T mismatches that result from the hydrolytic deamination of 5-methyl cytosines. TDG transcripts were uniformly and ubiquitously expressed from 7.5-13.5 days post-coitum, but were then markedly enriched in specific tissues of the developing fetus. At 14.5 gestational days, TDG was strongly expressed in the developing nervous system, thymus, lung, liver, kidney and intestine. At later stages, high levels of expression were detected in the thymus, brain, nasal epithelium and within proliferating regions of the intestine, skin, kidney, teeth and bone. This pattern of expression strongly correlated with those of the methyl transferase (MTase) gene, coding for the enzyme which specifically methylates CpG dinucleotides, and the p53 tumour suppressor gene. However, TDG and MTase were differentially expressed during maturation of the male and female germline. We also report that tumors occuring in mice which overexpress MMTV-v-Ha-ras or MMTV-c-myc transgenes or mice heterozygous for p53 gene disruption, all show elevated TDG and MTase expression specific to the transformed tissue. PMID: 9794235 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 633: Biochem Biophys Res Commun. 1998 Oct 20;251(2):488-93. Contrasting patterns of regulation of the antioxidant selenoproteins, thioredoxin reductase, and glutathione peroxidase, in cancer cells. Gladyshev VN, Factor VM, Housseau F, Hatfield DL. Department of Biochemistry, University of Nebraska, Lincoln, Nebraska, 68588, USA. vng@unlinfo2.unl.edu There is strong evidence that selenium protects against certain human cancers, but the underlying mechanism is unknown. Glutathione peroxidase (GPX1) and thioredoxin reductase (TR), the most abundant antioxidant selenium-containing proteins in mammals, have been implicated in this protection. We analyzed the expression of TR and GPX1 in the following model cancer systems: (1) liver tumors in TGFalpha/c-myc transgenic mice; (2) human prostate cell lines from normal and cancer tissues; and (3) p53-induced apoptosis in a human colon cancer cell line. TR was induced while GPX1 was repressed in malignancies relative to controls in transgenic mice and prostate cell lines. In the colon cell line, p53 expression resulted in elevated GPX1, but repressed TR. The data indicate that TR and GPX1 are regulated in a contrasting manner in the cancer systems tested and reveal the p53-dependent regulation of selenoprotein expression. The data suggest that additional studies on selenoprotein regulation in different cancers are required to evaluate future implementation of selenium as a dietary supplement in individuals at risk for developing certain cancers. Copyright 1998 Academic Press. PMID: 9792801 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 634: Eur J Oral Sci. 1998 Oct;106(5):907-13. Co-overexpression of p53 and c-myc proteins linked with advanced stages of betel- and tobacco-related oral squamous cell carcinomas from eastern India. Baral R, Patnaik S, Das BR. Molecular Biology Division, Institute of Life Sciences, Sahid Nagar, Bhubaneswar, India. Epidemiological evidence suggests that heavy consumption of betel quid and tobacco with areca nuts is the cause of high incidence of oral cancer in eastern part of Indian population, which is distinctly different from the etiology of oral squamous cell carcinomas (SCCs) in western countries. Here, expression of p53 and c-myc protein was studied in oral SCCs from this etiologically distinct population by immunohistochemistry. Out of 48 specimens of oral SCCs, 22 (45.8%) exhibited p53 positivity and 27 (56.3%) showed immunoreactivity with c-myc antibody. Considering the p53/c-myc expression pattern, either alone or in combination, the population was divided into four groups, i.e., both p53 and c-myc positive; p53 positive-c-myc negative; c-myc positive - p53 negative; and both p53 and c-myc negative. Tumours with both p53 and c-myc positivity were in advanced stages of the disease (poorly differentiated, tumour stage 3, nuclear grade III), whereas earliest stage of oral SCCs was detected in tumours with neither p53 nor c-myc immunoreactivity. Tumours of remaining two groups were generally restricted to early to moderate stages. These observations suggest that rapid progression of the betel- and tobacco-related oral SCCs may be associated with a simultaneous involvement of these two oncoproteins. The study also attempted to find out the relationship of p53/c-myc expression with spontaneous apoptosis. More apoptotic cells were found in c-myc positive but p53 negative tumours. This preliminary observation requires further molecular investigation of the role of p53 and c-myc genes for the progression of this epidemiologically distinct oral carcinogenesis. PMID: 9786319 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 635: Eur J Hum Genet. 1998 Jul-Aug;6(4):359-64. Asynchronous replication of allelic loci in Down syndrome. Amiel A, Avivi L, Gaber E, Fejgin MD. Genetic Institute, Meir Hospital, Kfar-Saba, Israel. We have used FISH to determine the level of synchronisation in replication timing of four pairs of alleles, unrelated to chromosome 21 (p53, HER2, RB1, and c-myc), in foetal (amniotic fluid) cell samples of Down syndrome and in normal foetuses. All samples derived from the Down syndrome subjects showed large temporal differences in replication timing, in contrast to the high level of synchrony shown in all samples of normal individuals. Thus, as judged by four independent loci which are not associated with chromosome 21, the additional chromosome in the Down syndrome genome induces changes in the replication pattern of an allelic pair: from a synchronous pattern characteristic to concomitantly expressed alleles to an unsynchronised one shown by alleles displaying an allele-specific mode of expression. PMID: 9781044 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 636: J Gastroenterol. 1998 Oct;33(5):782-3. Comment on: J Gastroenterol. 1998 Oct;33(5):710-5. Molecular and cytogenetic diagnosis of lymphoproliferative disorders of the gastrointestinal tract. Sugano K. Publication Types: Comment Editorial PMID: 9773953 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 637: Cancer Genet Cytogenet. 1998 Oct 1;106(1):11-7. Interphase cytogenetics of esophageal adenocarcinoma and precursor lesions. Persons DL, Croughan WS, Borelli KA, Cherian R. Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City 66160-7232, USA. Limited information is currently available on chromosomal abnormalities in esophageal adenocarcinoma and associated premalignant lesions. In this study, numeric changes affecting chromosomes 4, 6, 7, 8, 9, 10, 11, 12, 17, 18, X, and Y were analyzed by using fluorescence in situ hybridization (FISH) with chromosome-specific centromere DNA probes in 12 esophageal adenocarcinomas. In addition, TP53 overexpression, measured by immunohistochemistry, and amplification of HER-2/neu and C-MYC, detected by FISH, were analyzed within the same tumors. The most common numeric abnormalities detected were gains of chromosomes 12 (8 cases), 6 (7 cases), 7 (7 cases), and 11 (6 cases). The total number of abnormal chromosomes varied from 0 to 10, with an average of 4.6 per case. Overexpression of TP53 was present in 9 of 12 cases. No correlation was noted between the degree of aneusomy and TP53 overexpression. In contrast, HER-2/neu amplification was present in two cases, both with large numbers of aneusomic chromosomes. Amplification of C-MYC was detected in only one case that had a moderate number of numeric abnormalities. In a subset of cases in which premalignant lesions were examined, aneusomy was found to be an early change, frequently present in both Barrett's esophagus and dysplastic regions. In contrast, gene amplification and TP53 overexpression were restricted to more advanced areas of dysplasia and malignancy. Screening larger cohorts of patients with Barrett's esophagus or dysplasia for numeric abnormalities of chromosomes 6, 7, 11, and 12 may determine whether any of these abnormalities are predictive markers of progression to malignancy. PMID: 9772903 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 638: Int J Oncol. 1998 Nov;13(5):1017-22. Low MIB-1 labeling index in anti-HCV positive hepatocellular carcinoma. Watanuki A, Ohwada S, Fukusato T, Kawate S, Makita F, Morishita Y. Second Department of Surgery, Gunma University School of Medicine, Gunma 371-8511, Japan. It has been reported that hepatitis C virus-related hepatocellular carcinoma (HCC) patients survive longer than hepatitis B virus-related patients. In this study, since HCC patients positive for anti-HCV antibody had significantly longer disease-free survival (p<0.05), we evaluated the proliferative activity of 58 resected HCCs and the status of their viral infections. Ki-67 (MIB-1) immunostaining, argyrophilic nucleolar organizer regions and c-myc gene amplification were examined as parameters of proliferation, and p53 overexpression was examined in relation to clinicopathologic features and prognosis. Thirty-nine patients with HCC (67%) were positive for anti-HCV antibody alone, five (9%) were negative for both anti-HCV and HBV antibodies, two (3%) were positive for both anti-HCV and HBV antibodies, and 12 (21%) had HBsAg alone. HCC patients with anti-HCV antibody had a lower MIB-1 labeling index (LI) than HCC patients negative for the antibody (p<0.05), irrespective of the serum HBsAg status. However, there was no significant correlation between anti-HCV antibody and other proliferative parameters. MIB-1 could simply be related to cellular proliferation. On the other hand, the other parameters may be related to tumor progression as well as proliferation. HCV-related HCC does have lower proliferative activity and a better prognosis. PMID: 9772294 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 639: Pathol Biol (Paris). 1997 Dec;45(10):852-63. p53 and lung cancer. Brambilla E, Brambilla C. Lung Cancer Research Group, Institut Albert Bonniot, Faculte de Medecine, La Tronche, France. The malignant transformation of pulmonary epithelial cells is the result of multistep accumulation of genetic and molecular alterations highly related to tobacco carcinogens, involving key mechanisms of proliferation and apoptosis. Clonal expansion is the net result of acceleration of cell division and inhibition of active cell death (apoptosis). Oncogene activation in lung cancer (ras, myc, autocrine growth factor loops) results in acceleration of cell division. More importantly, tumor suppressor genes inactivation (p53, Rb, cyclin-dependent-kinase-Inhibitor p16) at genetic, epigenetic, or post-translational level removes important constraints on cell division at G1-check-point increasing cell proliferation. p 53 inactivation, through loss of transcription function may abrogate both G1-arrest control and apoptosis, thus accelerating clonal expansion. It is the most frequent alteration in lung cancer (70% of genetic alterations) with some differentiation dependent differences. p53 missense mutation is highly concordant with p53 stabilization and immunoreactivity. However, 20% of mutations with null phenotype (no p53 protein) provides 20% of false negative using immunohistochemistry for evaluation of p53 mutations in lung cancer. Rare situations are described with wild type p53 stabilization. p53 mutational spectrum in lung cancer reveals some specificities: 3 hot spot codons (codon 157, 248, 273) are the main target of selective adduct formation from a defined chemical carcinogen of cigarette smoke (BP). p53 stabilized mutants proteins are the targets for immune recognition in patients, leading to secretion of p53 auto-antibodies, and can also elicit T-cell specific cytotoxicity in vitro. p53 was not proven to be of prognostical importance once the tumor has developed. However, p53 stabilization is one of the best predictor of progression and irreversitiblity of preneoplastic bronchial lesion overwhelming morphological changes such as severe dysplasia. Restoration of wild type p53 function through p53 gene therapy, immunotherapy or modification of carboxy terminal end enable new therapeutic intervention. Finally, target genes and proteins situated on the downstream pathway of p53 transcription appears to be the most important factors of growth acceleration or even cell dissemination in lung cancer (Rb and its phosphorylation pathway, Bax-Bc12 balance and matrix degrading enzymes UPA and inhibitor PAI). Their constitutive deregulation could by-pass wild type p53 functions. p53 pathway offers several targets for future gene therapy or modulation in the future in lung cancer. Publication Types: Review PMID: 9769949 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 640: Cancer. 1998 Oct 1;83(7):1401-8. Comment in: Cancer. 1999 Jun 15;85(12):2668-9. Expression of ras, c-myc, and p53 proteins in cervical intraepithelial neoplasia. Slagle BL, Kaufman RH, Reeves WC, Icenogle JP. Division of Molecular Virology, Baylor College of Medicine, Houston, Texas 77030, USA. BACKGROUND: The development of cervical carcinoma is influenced by multiple factors, including the presence of certain high risk types of human papillomavirus. The purpose of the current study was to investigate possible cooperating genetic changes by examining the expression of p53, p62 myc, and p21 ras in cervical biopsy specimens. METHODS: Three hundred and ninety-five cervical biopsy specimens representing normal through high grade cervical intraepithelial neoplasia (CIN) were screened by immunohistochemistry for expression of p53, p62myc, and p21ras. RESULTS: Neither the proportion of tissues staining positive for a given protein nor the staining patterns within the epithelial layers differed significantly among normal or CIN biopsy samples. However, grade specific nuclear staining of p21ras was found in the cells of 10 lesions that were classified as CIN I by histology. CONCLUSIONS: These results established the normal distribution and expression patterns of p53, p62myc, and p21ras within 395 cervical biopsy samples representing normal through CIN III histology. The expression of these proteins (e.g., staining intensity and layer of epithelium staining positive) is similar in normal tissues and those demonstrating all grades of CIN. PMID: 9762942 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 641: Gastroenterol Clin Biol. 1998 Apr;22(4):381-93. [Apoptosis in normal and diseased liver] [Article in French] Guettier C, Ziol M. Service d'Anatomie et Cytologie Pathologiques, Hopital Jean Verdier, Bondy. Publication Types: Review Review, Tutorial PMID: 9762267 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 642: Cancer Lett. 1998 Aug 14;130(1-2):103-13. p53-independent dephosphorylation and cleavage of retinoblastoma protein during tamoxifen-induced apoptosis in human breast carcinoma cells. Fattman CL, An B, Sussman L, Dou QP. Department of Pharmacology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute, PA 15213-2582, USA. We have investigated several molecular events that occur during the process of tamoxifen-induced apoptosis in human breast carcinoma cells. We show that the treatment of either MCF-7 (containing wild-type p53) or MDA-MB-231 cells (containing mutant p53) with tamoxifen resulted in apoptotic nuclear changes and an increase in the pre-G1 apoptotic population. This was accompanied by activation of the caspase enzymes, as evidenced by specific cleavage of poly(ADP-ribose) polymerase and retinoblastoma (RB) protein. The RB protein was cleaved at both an interior and carboxyl terminus cleavage site. In addition, dephosphorylation of RB was found at an early stage of tamoxifen-induced apoptosis in both cell lines. However, neither induction of p53 in MCF-7 cells nor induction of p21 in either cell line was detected, suggesting that tamoxifen-induced RB dephosphorylation and apoptosis are independent of the p53/p21 pathway. We also observed an increase in levels of the pro-apoptotic Bax protein, the inhibitory cytokine TGF-beta1 and the transcription factor c-Myc in tamoxifen-treated MDA-MB-231 cells, suggesting the possible involvement of these proteins during apoptosis in this system. PMID: 9751262 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 643: Carcinogenesis. 1998 Aug;19(8):1481-6. HPV-16 E7 protein bypasses keratinocyte growth inhibition by serum and calcium. Pei XF, Sherman L, Sun YH, Schlegel R. Department of Pathology, Georgetown University Medical School, Washington, DC 20007, USA. The E6 and E7 genes of HPV-16 or HPV-18 both are necessary for effective immortalization of primary human genital keratinocytes. To analyse the individual role of E6 and E7 genes in dysregulating cell growth, we cloned the HPV-16 E6, E7 and E6/E7 genes into retroviruses. Primary human keratinocytes (PHK) were then infected with these retroviruses and selected in differentiation-inducing medium (high calcium and serum). The E6/E7 retroviruses were the most effective at inducing differentiation-resistant colonies. Intermediate numbers of colonies were induced by E6 and low numbers by E7. Interestingly, only cultures infected with E7 and E6/E7 retroviruses showed a significant proportion of cells progressing into the S phase, consistent with our earlier studies showing that E7 is required for the efficient immortalization of genital keratinocytes. Accompanying this entry into S phase, the E7 or E6/E7 transduced cells expressed high levels of cyclins A, B and E, but lower levels of cyclin D. In addition, cdc-2, cdk-2 and cdk-4 were also increased. No significant differences were detected in the expression of c-myc and c-fos between the vector and any of the transduced cells. Keratinocytes infected with the E7 retrovirus exhibited decreased levels of Rb protein and increased levels of p53, whereas cells infected with E6-expressing retroviruses displayed normal levels of Rb protein and decreased levels of p53. Finally, E7 induced a three-fold increase in bcl-2 expression. Our results indicate that the HPV-16 E7 gene alone is sufficient to bypass keratinoctye growth arrest induced by serum and calcium exposure and that the discordant expression of several cell regulatory proteins accompanies this unregulated proliferation. PMID: 9744546 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 644: Antisense Nucleic Acid Drug Dev. 1998 Aug;8(4):281-93. The influence of target protein half-life on the effectiveness of antisense oligonucleotide analog-mediated biologic responses. Spiller DG, Giles RV, Broughton CM, Grzybowski J, Ruddell CJ, Tidd DM, Clark RE. Department of Haematology, University of Liverpool, UK. During the course of a study aimed at improving antisense oligodeoxynucleotide-mediated ex vivo bone marrow purging of patients suffering from chronic myeloid leukemia (CML), the properties of a number of antisense structures intended to reduce the expression of c-myc, mutant p53, and bcr-abl mRNAs and proteins were examined. The majority of the antisense oligodeoxynucleotides were designed to be capable of directing ribonuclease H (RNase H) cleavage of their target mRNAs. Streptolysin O (SLO) reversible permeabilization was used to deliver the oligodeoxynucleotides into the CML line KYO-1. We found that the efficiency and specificity of antisense oligonucleotide-induced reductions of target protein expression depended on target protein half-life, the oligonucleotide structure, and the specific sequence within the target mRNA. Transient reductions of c-myc mRNA and protein were achieved with a chimeric methylphosphonate-phosphodiester oligodeoxynucleotide antisense to the initiation codon, but cell proliferation was unaffected. In contrast, a chimeric oligodeoxynucleotide of similar structure targeted to an alternative site in the coding region of c-myc mRNA reduced target mRNA and protein levels for over 24 hours and halted cell proliferation. Chimeric methylphosphonate-phosphodiester oligodeoxynucleotide antisense to a point mutation in KYO-1 p53 mRNA efficiently reduced target mRNA expression, but only small, transient reductions in p53 protein expression were observed. However, a chimeric methylphosphonate-phosphorothioate oligodeoxynucleotide targeted to the same site reduced p53 protein to 30% of control levels over a 48-hour period. BCR-ABL protein expression was unaffected by chimeric oligodeoxynucleotides targeted to the breakpoint in bcr-abl mRNA, even when mRNA levels at early times were substantially reduced. PMID: 9743466 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 645: Int J Oncol. 1998 Oct;13(4):807-18. Death activation does not stop tumor growth: quantitative evidence for concomitant activation of apoptosis in tumor growth in vitro. Watanabe H, Shinozaki T, Shiba S, Suzuki H, Takagishi K. Department of Orthopedic Surgery, Gunma University Faculty of Medicine, Maebashi, Gunma 371, Japan. A protein-independent fibrosarcoma, Gc-4 PF, grows exponentially in a protein-free medium. The doubling time (approximately 26 h) was similar to that of the serum-dependent parental clone, Gc-4 SD cultivated in the presence of fetal calf serum (FCS). We demonstrated here that the protein-free cultivation of Gc-4 PF cells concomitantly activates apoptotic phenotypes (one third of total cell population), including typical morphology, high uptake of Hoechst 33342 dye, and cleavage of DNA to large fragments, as observed in protein-deprived Gc-4 SD cell previously. Gc-4 SD cells arrested in the G0/G1-phase in response to the protein-free condition. In contrast, Gc-4 PF cells did not reach G0/G1 arrest in the protein-free condition; instead the durations of both G0/G1 and G2-phases were markedly reduced. The estimation of one cell cycle duration revealed that the cell division cycle was accelerated to 1.7 (27 h/15.4 h)-fold. Then the growth kinetics was able to be verified quantitatively by both the cell division rate and apoptotic cell loss. Protein-free cultivation resulted in slight down-regulation of c-myc protein in both cell types, while the down-regulation of p34cdc2, shown clearly in Gc-4 SD cells, was avoided in Gc-4 PF cells. Interestingly, while the expression of p53 was not affected in Gc-4 SD cells in response to the protein-free condition, the suppressor gene product expression was suppressed markedly in Gc-4 PF cells. These results suggest that Gc-4 PF cells may have acquired an ability to accelerate cell division by shortening the cell cycle duration to maintain a proper growth rate in response to intrinsic apoptosis activation with, at least in part, a suppression of p53 expression as well as an escape of down-regulation of p34cdc2. PMID: 9735412 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 646: Hepatology. 1998 Sep;28(3):727-37. Retinoic acid treatment induces apoptosis or expression of a more differentiated phenotype on different fractions of cultured fetal rat hepatocytes. Falasca L, Favale A, Gualandi G, Maietta G, Conti Devirgiliis L. Dept. Cell. Dev. Biology, University La Sapienza, Rome, Italy. The present study reports the effects of retinoic acid (RA) on cultured fetal rat hepatocytes. We show that RA treatment induces both differentiation and apoptosis. Hepatocytes cultured for 48 hours in the presence of 5 microl/L RA form junctional complexes in the areas of contact between neighboring cells and develop bile canaliculi, typical features of mature and well-differentiated cells. At the same time, about 20% of cells are induced to die by apoptosis, and the percentage of apoptotic cells increases according to the concentration of RA used and the duration of treatment. The induction of apoptosis, studied at the morphological and biochemical levels, revealed that, in our system, the classical compaction of chromatin occurs only during the final stages of the process; instead of the common marker of apoptosis, i.e., the "DNA ladder" pattern of fragmentation, megabase-sized fragments were found. These observations provide further evidence of the existence of fundamental differences in the mechanisms of apoptosis among cell types. To investigate the molecular mechanism of the effects of RA, we evaluated the expression of two proteins, c-myc and p53, which are known to be involved in both cell differentiation and apoptosis. The data obtained show that the amount of p53 remained unchanged after RA treatment. On the contrary, a dose-dependent reduction in c-myc levels was found, suggesting that RA action may be mediated by modulation of this oncogene. Our findings regarding the apoptosis-inducing effect of RA, which was not found in adult hepatocytes, suggest a possible relationship between this phenomenon and the proliferative capacity and/or differentiation state of hepatocytes. PMID: 9731565 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 647: Cancer Detect Prev. 1998;22(5):422-9. Predictive value of molecular alterations for the prognosis of urothelial carcinoma. Schulz WA, Jankevicius F, Gerharz CD, Kushima M, van Roeyen C, Bultel H, Gobell P, Schmitz-Drager BJ. Department of Urology, Heinrich-Heine University Dusseldorf, Germany. Accumulation of p53 and C-Myc overexpression are frequently found in advanced urothelial carcinomas. The prevalence and predictive value of both molecular alterations was investigated in 61 patients with superficial urothelial tumors. Distinct patterns of p53 accumulation and C-Myc overexpression were observed in superficial urothelial carcinoma of different stages. For instance, 67% of carcinomata in situ displayed accumulation of p53, but only 44% showed C-Myc overexpression, whereas in pT1 tumors the corresponding percentages were 25 and 75%. Similarly, while p53 accumulation was significantly (p = 0.02) associated with tumor grade, C-Myc overexpression did not correlate with grade. In multivariate analysis, p53 accumulation was found to be an independent predictor of tumor progression (p = 0.0096), whereas C-Myc overexpression did not correlate with the course of disease. Alterations in both markers together predicted neither tumor recurrence nor tumor progression better than p53 accumulation on its own. Sufficient expression of C-Myc may be a general requirement for proliferative competence in urothelial tumors, barring its use as a predictive marker. The predictive value of p53 accumulation for tumor progression was further underlined by the finding that in a distinct group of 52 patients with progressive urothelial carcinoma 73% of the recurrent tumors displayed p53 accumulation. PMID: 9727623 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 648: Cancer Detect Prev. 1998;22(5):405-15. Expression of lymphomagenic oncogenes in T-cell lymphomas of HPV 16 transgenic mice. Yang JT, Liu CZ, Domer P, Iannaccone P. Department of Pediatrics and the Children's Memorial Institute for Education and Research, Northwestern University Medical School, Chicago, IL 60614, USA. We have previously established that a dimer repeat of the complete HPV 16 genome is sufficient to cause multiple organ malignancies, either carcinomas or T-cell lymphomas, in transgenic mice. Here, we report the expression of oncogenes supporting the notion that these tumors arose via multiple oncogenic pathways. In these mice, the transgenic HPV 16 genome cosegregated with the tumor phenotype. E6/E7 expression was observed in both carcinomas and T-cell lymphomas, while E2 expression was observed only in T-cell lymphomas. Some of the T-cell lymphomas revealed E2 expression alone, implying that oncogenic pathways of HPV other than the one involving E6/E7 existed in these transgenic mice. To establish that this is the case, expression of genes downstream from E6/E7 and oncogenes involved in T-cell lymphoma formation were analyzed. p53 mutations were observed in two of five tumors that lacked E6 expression. High levels of c-myc gene expression were observed in five of six tumors with E7 expression, suggesting that a pathway involving E7, inactivation of Rb, and activation of c-myc is important in tumorigenesis of HPV 16 in these transgenic animals. High levels of expression of the c-Pim gene were also noted in two of three c-myc-expressing T-cell lymphomas, suggesting cooperation between these two proto-oncogenes. Activation of Hox-11, Tal2/SCL-2, and Rbtn1/Ttg1 expression, which are highly associated with human T-cell acute lymphoblastic leukemia (T-ALL), was observed in three of three T-cell lymphomas with E2 expression but not E6/E7 expression, showing that pathways to tumor formation not involving E6/E7 exist in these transgenic animals. At least two oncogenic pathways to tumors in HPV 16 transgenic mice exist, one involving E6/E7 and c-myc and the other involving E2 and lymphomagenic oncogenes. PMID: 9727621 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 649: Cancer Detect Prev. 1998;22(5):383-95. Genetic abnormalities and microsatellite instability in colorectal cancer. Iniesta P, de Juan C, Caldes T, Vega FJ, Massa MJ, Cerdan FJ, Lopez JA, Fernandez C, Sanchez A, Torres AJ, Balibrea JL, Benito M. Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Spain. Our purpose was to investigate different genetic abnormalities, such as K-ras mutations, p53 alterations, and c-myc RNA overexpression, as well as microsatellite instability in 63 colorectal tumors obtained from patients that had undergone surgery. K-ras point mutations were analyzed by PCR-RFLP technique, followed by sequencing; p53 protein accumulation by immunohistochemistry; p53 gene mutations in exons 5-9 were studied by the SSCP and sequencing techniques, and c-myc overexpression by Northern blot. Microsatellite instability was performed at chromosomes 2p, 3p, and 11p by a PCR-based technique. Our data indicate a trend toward a poorer prognosis in patients who had K-ras transversions; besides, we have obtained a prevalence of c-myc RNA overexpression and p53 exon 7 mutations in the latest stages of tumor progression. In conclusion, our findings suggest that the recognition of molecular abnormalities might be used in colorectal cancer as a prognostic indicator or to determine the metastatic potential of colorectal adenocarcinomas. PMID: 9727619 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 650: Histopathology. 1998 Jul;33(1):64-70. Apoptosis is associated with atypical or malignant change in meningiomas. An in situ labelling and immunohistochemical study. Ng HK, Chen L. Department of Anatomical & Cellular Pathology, Chinese University of Hong Kong. AIMS: Although necrosis is an important phenomenon with implications for grading and prognostication in meningiomas, the alternate form of cell death, apoptosis, has not been extensively studied. In this series, we aimed to determine whether apoptosis in meningiomas correlated with histological types and grading. We also looked for a relationship between expression of apoptosis-related genes bcl-2, p53, c-myc and apoptosis meningiomas. METHODS AND RESULTS: Fifty-one meningiomas of diverse histological subtypes and grades were investigated with in situ end-labelling of DNA fragments as well as immunohistochemical analysis of three apoptosis-related genes: p53, bcl-2 and c-myc. Our results showed that the apoptosis index was significantly higher in high-grade meningiomas (0.12%, n = 12) in than the benign meningiomas (0.023%, n = 39) P = 0.001) but there was no difference among the different histological subtypes of the benign meningiomas (P = 0.125). There is no obvious relationship between p53, bcl-2 and c-myc staining and apoptosis index in this group of meningiomas. CONCLUSION: We conclude that apoptosis is an important phenomenon in meningiomas and that it is associated with atypical or malignant changes in meningiomas. Apoptosis in meningiomas has no clearcut relationship with expression of p53, bcl-2 and c-myc. PMID: 9726051 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 651: Br J Pharmacol. 1998 Jul;124(6):1029-40. Effect of curcumin on cell cycle progression and apoptosis in vascular smooth muscle cells. Chen HW, Huang HC. Department of Pharmacology, College of Medicine, National Taiwan University, Taipei. 1. The possible mechanisms of the antiproliferative and apoptotic effects of curcumin (diferuloylmethane), a polyphenol in the spice turmeric, on vascular smooth muscle cells were studied in rat aortic smooth muscle cell line (A7r5). 2. The proliferative response was determined from the uptake of [3H]-thymidine. Curcumin (10(-6)-10(-4) M) inhibited serum-stimulated [3H]-thymidine incorporation of both A7r5 cells and rabbit cultured vascular smooth muscle cells in a concentration-dependent manner. Cell viability, as determined by the trypan blue dye exclusion method, was unaffected by curcumin at the concentration range 10(-6) to 10(-5) M in A7r5 cells. However, the number of viable cells after 10(-4) M curcumin treatment was less than the basal value (2 x 10(5) cells). 3. To analyse the various stages of the cell cycle, [3H]-thymidine incorporation into DNA was determined every 3 h. After stimulation with foetal calf serum, quiescent A7r5 cells started DNA synthesis in 9 to 12 h (G1/S phase), then reached a maximum at 15 to 18 h (S phase). Curcumin (10(-6)-10(-4) M) added during either the G1/S phase or S phase significantly inhibited [3H]-thymidine incorporation. 4. Following curcumin (10(-6)-10(-4) M) treatment, cell cycle analysis utilizing flow cytometry of propidium iodide stained cells revealed a G0/G1 arrest and a reduction in the percentage of cells in S phase. Curcumin at 10(-4) M also induced cell apoptosis. It is suggested that curcumin arrested cell proliferation and induced cell apoptosis, and hence reduced the [3H]-thymidine incorporation. 5. The apoptotic effect of 10(-4) M curcumin was also demonstrated by haematoxylin-eosin staining, TdT-mediated dUTP nick end labelling (TUNEL), and DNA laddering. Curcumin (10(-4) M) induced cell shrinkage, chromatin condensation, and DNA fragmentation. 6. The membranous protein tyrosine kinase activity stimulated by serum in A7r5 cells was significantly reduced by curcumin at the concentration range 10(-5) to 10(-4) M. On the other hand, the cytosolic protein kinase C activity stimulated by phorbol ester was reduced by 10(-4) M curcumin, but unaffected by lower concentrations (10(-6)-10(-5) M). 7. The levels of c-myc, p53 and bcl-2 mRNA were analysed using a reverse transcription-polymerase chain reaction (RT-PCR) technique. The level of c-myc mRNA was significantly reduced by curcumin (10(-5)-10(-4) M) treatment. And, the level of bcl-2 mRNA was significantly reduced by 10(-4) M curcumin. However, the alteration of the p53 mRNA level by curcumin (10(-5)-10(-4) M) treatment did not achieve significance. The effects of curcumin on the levels of c-myc and bcl-2 mRNA were then confirmed by Northern blotting. 8. Our results demonstrate that curcumin inhibited cell proliferation, arrested the cell cycle progression and induced cell apoptosis in vascular smooth muscle cells. Curcumin may be useful as a template for the development of drugs to prevent the pathological changes of atherosclerosis and post-angioplasty restenosis. Our results suggest that the antiproliferative effect of curcumin may partly be mediated through inhibition of protein tyrosine kinase activity and c-myc mRNA expression. And, the apoptotic effect may partly be mediated through inhibition of protein tyrosine kinase activity, protein kinase C activity, c-myc mRNA expression and bcl-2 mRNA expression. PMID: 9720770 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 652: Leuk Lymphoma. 1998 Sep;31(1-2):1-19. Cytogenetic changes in the progression of lymphoma. Knutsen T. Cytogenetics Laboratory, Experimental Therapeutics Section Medicine Branch, NCI National Institutes of Health, Bethesda, MD, USA. turidk@Box-t.nih.gov The study of chromosomal changes related to tumor progression in NHL is complicated by the various histologic classification systems and the lack of large serial studies comparing abnormalities at different disease stages. The T-cell lymphomas frequently involve rearrangements of the T-cell receptors and tumor progression is marked by a change from single cell aberrations and polyclonality in low grade disease to monoclonal formation, complex clones, polyploidy, and abnormalities of 1p, 6q, 7, and 13 in high grade T-NHL. In B-cell NHL, specific translocations and oncogene rearrangements are associated with specific NHL subtypes de novo; many of these translocations involve immunoglobulin genes, such as t(14;18) in follicular lymphoma, t(11;14) in MCL, t(3;14) in DLLC, and t(8;14) in Burkitt's lymphoma. Tumor progression is associated with secondary abnormalities which are generally not confined to a particular NHL subtype. Some abnormalities, such as those involving chromosomes 1, 6, and 17, >4-6 clonal markers/cell, and rearrangements of c-MYC and TP53, have prognostic significance while others, such as trisomies 7, 12, 18, and X, are associated with tumor progression but their influence on overall survival is uncertain. Publication Types: Review PMID: 9720711 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 653: Cancer Lett. 1998 Jul 17;129(2):165-71. p53 may mediate the mdr-1 expression via the WT1 gene in human vincristine-resistant leukemia/lymphoma cell lines. Hirose M, Kuroda Y. Division of Transfusion Medicine, School of Medicine, The University of Tokushima, Tokushima City, Japan. hirose@clin.med.tokushima-u.ac.jp To investigate the regulatory mechanism of the expression of the multidrug resistance gene (mdr-1) and the multidrug resistance-associated protein gene (mrp), we investigated if p53, WT1, RB, C-myc, N-myc, cyclin D1, p16INK4 (p16) are involved in the acquirement of multidrug resistance phenotype (MDR) in human vincristine (VCR)-resistant cells of leukemia/lymphoma cell lines. By using RT-PCR, we observed that MDR in VCR-resistant cell lines was mediated by either mdr-1 or mrp genes. In cells that acquired the overexpression of mdr-1, downregulation of p53 and upregulation of WT-1 were observed. In contrast, no constant change of genes was observed in cells that overexpressed mrp. Although the change in the expression level of cyclin D1 and p-16 accompanied the development of VCR resistance, the mRNA of RB, C-myc and N-myc showed no correlation with the degree of VCR resistance or the level of mdr-1 expression. These results may provide a plausible diagnostic marker for determination of drug sensitivity in cancer patients and suggest that p53 may mediate directly or indirectly the expression of mdr-1 via WT1 in VCR-resistant hematologic cell lines. PMID: 9719458 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 654: Arkh Patol. 1998 May-Jun;60(3):5-10. [Morphologic and molecular-genetic characteristics of carcinoma, adenoma and surrounding tissue of the thyroid gland] [Article in Russian] Pal'tsev MA, Kogan EA, Tuntsova OI, Severin ES, Silaeva SA, Golenchenko VA. I. M. Sechenov Moscow Medical Academy. The majority of thyroid tumors are not homogeneous histologically, this creating difficulties in interpretation of different carcinoma variants. The aim of the study was a complex comparative study of morphogenetic changes in carcinoma, adenoma and surrounding thyroid tissue. Surgical material from 48 patients operated because of nodular (multinodular) euthyroid goiter in Moscow Medical Academy in 1990-1997 was used. It was established that all the observations of early thyroid carcinoma diagnosed clinically as a nodular (multinodular) euthyroid goiter were represented by differentiated forms of thyroid carcinoma. Thyroid carcinoma was characterized by higher values of biomolecular markers as compared to adenomas and surrounding tissue. High values of c-myc expression in adenomas and surrounding tissue may indicate possible genetic rearrangements. A peculiar feature of carcinomas was the fact that deletions and replication errors in malignant tumors in this study were found simultaneously in the three genes investigated. As to different histological types of carcinoma, the most frequent deletions of the genes studied were observed in medullary and papillary-follicular carcinoma. High values of heterozygosity loss were found already in adenomas and surrounding tissues, this indicating the presence of the genetic changes already in the benign tumors and surrounding tissue. Publication Types: Clinical Trial Controlled Clinical Trial PMID: 9702292 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 655: Endocr J. 1998 Apr;45(2):247-53. Serum deprivation-induced apoptosis in cultured porcine granulosa cells is characterized by increased expression of p53 protein, Fas antigen and Fas ligand and by decreased expression of PCNA. Peng X, Maruo T, Matsuo H, Takekida S, Deguchi J. Department of Obstetrics and Gynecology, Kobe University School of Medicine, Japan. Although serum deprivation induces apoptosis in several cell lines, biochemical characterization of the apoptosis in primary granulosa cells (GCs) induced by serum deprivation has rarely been reported. In the present study, GCs from small follicles of porcine ovaries were precultured under a serum-containing condition for seven days, then stepped down to a serum-free condition and cultured for the subsequent two days. GCs were subjected to DNA fragmentation and immunoblot analyses. Data indicated that serum deprivation induced GC apoptosis characterized by DNA laddering, which was associated with decreased expression of proliferating cell nuclear antigen (PCNA) and increased expression of p53 protein, Fas antigen and Fas ligand. Serum deprivation also resulted in an increase in a 115 kDa protein expression despite no detectable expression of a 66 kDa c-myc protein. This suggests that serum removal from primary GCs may activate multiple apoptotic pathways such as a p53-associated pathway and a Fas-Fas ligand pathway. PMID: 9700479 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 656: Cancer Res. 1998 Aug 1;58(15):3193-6. Molecular genetic characterization of BRCA1- and BRCA2-linked hereditary ovarian cancers. Rhei E, Bogomolniy F, Federici MG, Maresco DL, Offit K, Robson ME, Saigo PE, Boyd J. Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. Hereditary ovarian cancers associated with germline mutations in either BRCA1 or BRCA2 were studied to determine whether somatic mutation of the P53 gene is required for BRCA-linked ovarian tumorigenesis and further, whether the spectrum of additional somatic molecular genetic alterations present in these tumors differs from that known to exist in sporadic ovarian cancers. Forty tumors, 29 linked to BRCA1 and 11 linked to BRCA2, were examined for mutational alterations in P53, K-RAS, ERBB-2, C-MYC, and AKT2. The presence of a P53 mutation in 80% of these cancers indicates that P53 mutation is common but not required for BRCA-linked ovarian tumorigenesis; notably, a significantly higher proportion of the P53 mutations in BRCA2-linked cancers were deletions or insertions compared with the more typical spectrum of missense mutations seen in BRCA1-linked cancers. Additionally, BRCA-linked ovarian carcinomas seem to develop through a unique pathway of tumorigenesis that does not involve mutation of K-RAS or amplification of ERBB-2, C-MYC, or AKT2. PMID: 9699640 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 657: J Cutan Pathol. 1998 May;25(5):244-51. Different patterns of cell proliferation and death and oncogene expression in cutaneous malignant melanoma. Miracco C, Santopietro R, Biagioli M, Lazzi S, Nyongo A, Vatti R, Luzi P. Institute of Pathological Anatomy and Histology, University of Siena, Italy. hpv@unisi.it Ninety-six cutaneous melanomas (CMs) were investigated aiming at finding differences, if any, among the main four clinicopathological types, for Bcl-2, c-myc and p53 protein expression, and for tumor cell proliferation and death indices. Proliferation was assessed by calculating the mitotic index (MI, number of mitoses) and the MIB1 labelling index (M-LI, number of MIB1+ nuclei), and tumor cell death by calculating the apoptotic index (AI, number of apoptoses) among 1000 tumor cells. CMs were subdivided into thin (<1 mm) and intermediate thickness (1-4 mm) tumors. Bcl-2 expression did not significantly change among different types. c-myc Expression decreased especially in thicker superficial spreading (SSM) and lentigo maligna melanoma (LMM) types. p53 Expression was higher in nodular melanoma (NM) and in acral lentiginous melanoma(ALM), which also showed the highest degrees of proliferation. AI was significantly higher in thin rather than in intermediate thickness SSMs, LMMs and ALMs (8.4 vs. 2; 6.1 vs. 2.3, and 5.8 vs. 3.6, respectively). AI was low in thin (1.7) and intermediate thickness (1.9) NMs, which also showed high MI (3.9 and 4.5, respectively), and M-LI (16.7 and 2.9, respectively). Thin and intermediate thickness ALMs also showed high MI and M-LI (4.1 vs. 5.2 and 11.3 vs. 14.6, respectively). Bcl-2 is among genes which inhibit apoptotic death, whereas c-myc and p-53 genes promote this process. In CMs, no relation was found between Bcl-2 expression, MI, PI, and AI. All SSMs, LMMs, and ALMs with a high AI showed a high c-myc expression and were negative for p53. c-myc, Although highly expressed, did not promote a significant apoptotic death in NM type. Bc12, c-myc, and p53 were not equally expressed nor equally related to tumor cell turnover in all CMs, suggesting their different influence on the various types and stages, and the role of other factors in CM growth control. PMID: 9696289 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 658: Genes Dev. 1998 Aug 1;12(15):2424-33. Myc signaling via the ARF tumor suppressor regulates p53-dependent apoptosis and immortalization. Zindy F, Eischen CM, Randle DH, Kamijo T, Cleveland JL, Sherr CJ, Roussel MF. Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis Tennessee 38105 USA. Establishment of primary mouse embryo fibroblasts (MEFs) as continuously growing cell lines is normally accompanied by loss of the p53 or p19(ARF) tumor suppressors, which act in a common biochemical pathway. myc rapidly activates ARF and p53 gene expression in primary MEFs and triggers replicative crisis by inducing apoptosis. MEFs that survive myc overexpression sustain p53 mutation or ARF loss during the process of establishment and become immortal. MEFs lacking ARF or p53 exhibit an attenuated apoptotic response to myc ab initio and rapidly give rise to cell lines that proliferate in chemically defined medium lacking serum. Therefore, ARF regulates a p53-dependent checkpoint that safeguards cells against hyperproliferative, oncogenic signals. PMID: 9694806 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 659: Anticancer Res. 1998 May-Jun;18(3B):1907-14. Bcl2 and p53 protein expression in metastatic carcinoma of unknown primary origin: biological and clinical implications. A Hellenic Co-operative Oncology Group study. Briasoulis E, Tsokos M, Fountzilas G, Bafaloukos D, Kosmidis P, Samantas E, Skarlos D, Nicolaides C, Pavlidis N. Department of Medicine, Medical School, Ioannina University, Greece. We have previously shown that metastatic carcinomas of unknown primary site overexpress several tumor markers as well as the products of the oncogenes c-myc, ras and c-erbB2. We analyzed the tissue expression of the protein products of the apoptosis modulation genes p53 and bcl-2 in 47 CUP cases. Formalin-fixed, paraffin embedded tumor specimens were stained with commercially available antibodies to p53 (DO7) and bcl-2 after antigen retrieval by the microwave method. Staining was evaluated by intensity (1+ to 3+), percentage of positive cells (1-100%), and the 'intensity times percentage' product defined as the immunoreactivity index with values ranging from 0 to 300. Immunoreactivity index values higher than 150 were considered to characterize protein over-expression. Expression of p53 was identified in 70.2% of tumors while 53% of them showed a high immunoreactivity index. Bcl-2 expression was detected in 65% of tumors and overexpressed in 40%. Overexpression of both proteins was detected in 20% of tumors. The detection of either protein was not associated with any of the major clinicopathological variables studied. Nevertheless, a trend towards a more favourable response to platin based chemotherapy was seen in the cases that showed a strong expression of both proteins, when analysed by immunoreactivity index and percentage of positive cells. We conclude that CUP overexpress at a high percentage the p53 and the bcl2 proteins. The observed weak association of strong expression of these proteins with response to platin-based chemotherapy deserves further evaluation in the CUP setting. PMID: 9677443 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 660: Br J Cancer. 1998 Jun;77(11):1971-7. Prognostic value of genomic damage in non-small-cell lung cancer. de Juan C, Iniesta P, Vega FJ, Peinado MA, Fernandez C, Caldes T, Massa MJ, Lopez JA, Sanchez A, Torres AJ, Balibrea JL, Benito M. Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad Complutense, Madrid, Spain. Genomic alterations have been analysed in 65 non-small-cell lung cancer (NSCLC) tissue samples by using the arbitrarily primed polymerase chain reaction (AP-PCR), which is a PCR-based genomic fingerprinting. We have shown that AP-PCR may be applied as a useful and feasible practical method for detection of the genomic alterations that accompany malignancy in NSCLC. Genomic changes detected by us consisted of: allelic losses or gains in anonymous DNA sequences, homozygously deleted DNA sequences and polymorphic DNA sequences. According to these genomic changes, lung tumours evaluated in the present study have been scored into three groups: low, moderate and high genomic damage tumours. The aim of this study was to investigate the effect of genomic damage on patient survival. Survival analysis was carried out in 51 NSCLC patients. Our results revealed that high genomic damage patients showed a poorer prognosis than those with low or moderate genomic damage (P = 0.038). Multivariate Cox regression analysis showed that patients with higher genomic alterations displayed an adjusted-by-stage risk ratio 4.26 times higher than the remaining patients (95% CI = 1.03-17.54). We can conclude that genomic damage has an independent prognostic value of poor clinical evolution in NSCLC. PMID: 9667677 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 661: Mol Hum Reprod. 1998 May;4(5):477-81. Oncogene and tumour suppressor gene products during trophoblast differentiation in the first trimester. Quenby S, Brazeau C, Drakeley A, Lewis-Jones DI, Vince G. Department of Obstetrics and Gynaecology, University of Liverpool, UK. Tumour suppressor genes may have a role in the control of trophoblast cell population expansion as trophoblast invasion occurs. To investigate this hypothesis, the location of tumour suppressor gene and proto-oncogene products were studied at various stages of trophoblast differentiation and invasion. Trophoblast and decidua were obtained from eight women having a therapeutic termination of pregnancy. Immunohistochemistry was used to localize the products of c-myc, c-erB-2, RB, BCL-2, P21, and P53 genes and anti-cytokeratin was used to identify fetal cells amongst the maternal decidual cells. The most differentiated and furthest invading trophoblast cell type, the multinucleated trophoblast, expressed a combination of genes which may indicate a high apoptotic rate. The other fully differentiated trophoblast, the syncytiotrophoblast, expressed BCL-2 suggesting protection from apoptosis. The co-occurrence of proto-oncogenes and the products of tumour suppressor genes in first trimester trophoblast suggests an important role not only in negative regulation of cellular invasion but also in population expansion through the presence of oncogenes and anti-apoptotic proteins. PMID: 9665634 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 662: Nat Med. 1998 Jul;4(7):844-7. Comment in: Nat Med. 1998 Jul;4(7):767-8. Tissue microarrays for high-throughput molecular profiling of tumor specimens. Kononen J, Bubendorf L, Kallioniemi A, Barlund M, Schraml P, Leighton S, Torhorst J, Mihatsch MJ, Sauter G, Kallioniemi OP. Laboratory of Cancer Genetics, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-4470, USA. Many genes and signalling pathways controlling cell proliferation, death and differentiation, as well as genomic integrity, are involved in cancer development. New techniques, such as serial analysis of gene expression and cDNA microarrays, have enabled measurement of the expression of thousands of genes in a single experiment, revealing many new, potentially important cancer genes. These genome screening tools can comprehensively survey one tumor at a time; however, analysis of hundreds of specimens from patients in different stages of disease is needed to establish the diagnostic, prognostic and therapeutic importance of each of the emerging cancer gene candidates. Here we have developed an array-based high-throughput technique that facilitates gene expression and copy number surveys of very large numbers of tumors. As many as 1000 cylindrical tissue biopsies from individual tumors can be distributed in a single tumor tissue microarray. Sections of the microarray provide targets for parallel in situ detection of DNA, RNA and protein targets in each specimen on the array, and consecutive sections allow the rapid analysis of hundreds of molecular markers in the same set of specimens. Our detection of six gene amplifications as well as p53 and estrogen receptor expression in breast cancer demonstrates the power of this technique for defining new subgroups of tumors. PMID: 9662379 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 663: Oncogene. 1998 Jun 11;16(23):2965-74. p53 deficiency and misexpression of protein kinase CK2alpha collaborate in the development of thymic lymphomas in mice. Landesman-Bollag E, Channavajhala PL, Cardiff RD, Seldin DC. Department of Medicine, Boston University Medical Center, Massachusetts 02118, USA. Protein kinase CK2 (casein kinase II) is a serine-threonine protein kinase with many substrates, some of which are involved in cell cycle regulation. CK2 activity is elevated in human solid tumors and leukemia, and dysregulated expression of CK2 induces lymphoma in transgenic mice. Mice that are deficient in p53 also develop lymphomas, and p53 activity may be regulated by CK2 phosphorylation. Here we demonstrate that CK2alpha transgenic mice partially or completely deficient in p53 develop thymic lymphomas at a markedly accelerated rate when compared to p53-deficient mice lacking the transgene. Lymphomas originating from CK2alpha transgenic mice that are heterozygous for p53 generally lose the wild type p53 allele, indicating that loss of p53 is an important step in tumor progression. Moreover, though lymphomas occur as early as 3 weeks of age in the transgenic mice that are nullizygous for p53, they are still monoclonal, indicating that additional stochastic mutations are required for their development. These lymphomas express high levels of myc mRNA and frequently ectopically express Lmo-2, a transcription factor involved in human T cell acute lymphocytic leukemia. The p53-null CK2alpha transgenic lymphomas grow rapidly but are highly prone to apoptosis, suggesting that transformation occurs through synergistic dysregulation of cell cycle control induced by misexpression of CK2 and loss of function of p53. PMID: 9662328 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 664: Oncogene. 1998 May 28;16(21):2755-66. Myc/p53 interactions in transgenic mouse mammary development, tumorigenesis and chromosomal instability. McCormack SJ, Weaver Z, Deming S, Natarajan G, Torri J, Johnson MD, Liyanage M, Ried T, Dickson RB. The Lombardi Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA. We have examined defects in mammary development and tumorigenesis in a transgenic model expressing the c-myc gene under the MMTV-LTR promoter. The stochastic tumors which arise from hyperplastic ductal and lobular lesions in this model are characterized by high rates both of apoptosis and of chromosomal instability. Since the p53 gene product is thought to be central in the maintenance of genomic integrity, in part due to its ability to induce apoptosis in cells harboring DNA damage, we examined its expression and possible mutation. Initially, we observed that unmutated p53 is strongly expressed in premalignant mammary glands and in mammary tumors derived from the MMTV-c-myc strain. We then mated the MMTV-myc strain to a p53-deficient strain as a means of examining the effect of this lesion on mammary development and tumorigenesis in the context of c-myc overexpression. A lack of both p53 alleles in the presence of c-myc overexpression resulted in a dramatic hyerplastic alteration in mammary gland development. Specifically, in female bitransgenic MMTV-c-myc/p53 null mice (MMTV-myc/p53(-/-)), lobular hyperplasias were observed at almost every ductal end bud as early as 32 days of age. In contrast, only mild ductal and lobular hyperplasias were seen in MMTV-myc mice that contained both p53 alleles (MMTV-myc/p53(+/+)); an intermediate phenotype occurred in mice with a single intact (MMTV-myc/p53(+/-)) p53 allele. Mammary carcinomas arose with a high frequency in MMTV-myc/p53(+/-) mice; the tumors were comparable in frequency, histology and apoptotic index to the tumors in MMTV-myc/p53(+/+) mice. Also, as previously observed (Elson et al., 1995), lymphomas arose with extremely short latency in MMTV-myc/p53(-/-) mice, precluding study of the fate of their hyperplastic mammary lesions in situ. The frequency of p53 mutations in MMTV-myc/p53(+/+) and MMTV-myc/p53(+/-) mammary tumors and in cell lines derived from these tumors was examined by direct sequencing. No point mutations or deletions in p53 were observed in mammary tumors or cell lines from either genotype. Finally, a detailed chromosomal analysis using multicolor spectral karyotyping (SKY) revealed that there were multiple chromosomal alterations in the c-myc-overexpressing cells that contained either one or two unmutated p53 alleles. Variable ploidy changes, a common translocation of chromosome 11, and other chromosomal aberrations were observed. Our data thus support an interaction between c-Myc and p53 in mammary development, but suggest that loss of p53 is required neither for c-myc-dependent tumorigenesis nor for c-myc-dependent chromosomal instability. PMID: 9652742 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 665: Br J Cancer. 1998 Jun;77(12):2349-56. Moderate amplifications of the c-myc gene correlate with molecular and clinicopathological parameters in colorectal cancer. Masramon L, Arribas R, Tortola S, Perucho M, Peinado MA. Institut de Recerca Oncologica (Department of Cancer and Metastasis), Hospital Duran i Reynals, Barcelona, Spain. C-myc gene activation is a common event in multiple types of neoplasia and has been associated with different cellular processes relevant to the malignant transformation of cancer cells. C-myc gene amplification has been analysed in colorectal carcinomas by means of an innovative DNA fingerprinting method based on the arbitrarily primed PCR. This method requires a low amount of DNA, uses multiple internal controls and appears sensitive and reproducible. Clinicopathological and molecular correlates have been investigated in a series of 70 colorectal carcinomas. The incidence of c-myc amplification was 26%, ranging from two- to fivefold increase in copy number. C-myc amplification occurrence was more frequent in more advanced stages of tumour invasion (P < 0.001) and was associated with mutations in the p53 tumour-suppressor gene (P = 0.048). The presence of c-myc amplification was indicative of a shorter disease-free survival period but, because of its strong association with Dukes' stage, its prognostic value is questionable. PMID: 9649157 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 666: Mol Cell Biol. 1998 Jul;18(7):3735-43. Activation of c-myc gene expression by tumor-derived p53 mutants requires a discrete C-terminal domain. Frazier MW, He X, Wang J, Gu Z, Cleveland JL, Zambetti GP. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. Mutation of the p53 tumor suppressor gene is the most common genetic alteration in human cancer, and tumors that express mutant p53 may be more aggressive and have a worse prognosis than p53-null cancers. Mutant p53 enhances tumorigenicity in the absence of a transdominant negative mechanism, and this tumor-promoting activity correlates with its ability to transactivate reporter genes in transient transfection assays. However, the mechanism by which mutant p53 functions in transactivation and its endogenous cellular targets that promote tumorigenicity are unknown. Here we report that (i) mutant p53 can regulate the expression of the endogenous c-myc gene and is a potent activator of the c-myc promoter; (ii) the region of mutant p53 responsiveness in the c-myc gene has been mapped to the 3' end of exon 1; (iii) the mutant p53 response region is position and orientation dependent and therefore does not function as an enhancer; and (iv) transactivation by mutant p53 requires the C terminus, which is not essential for wild-type p53 transactivation. These data suggest that it may be possible to selectively inhibit mutant p53 gain of function and consequently reduce the tumorigenic potential of cancer cells. A possible mechanism for transactivation of the c-myc gene by mutant p53 is proposed. PMID: 9632756 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 667: In Vivo. 1998 Mar-Apr;12(2):201-7. Early effect of cyclophosphamide on oncogene expression in vivo. Ember I, Kiss I, Vermes E. Department of Preventive Medicine, University Medical School of Pecs, Hungary. Cyclophosphamide (CP) is a widely used chemotherapeutic drug, with proven carcinogenic effects. Secondary tumours induced by CP are kidney tumours in humans and haemopoietic malignancies in rodents. Previous experiments have shown its effect on H-ras, c-myc and p53 gene expression in long term in vivo experiments. Our model was developed to analyse the events in the first 24 hours after the administration of CP in short term experiments. The expression of Ha -ras, c-myc and p53 was investigated in the target organs during and up to 24 hours after the administration, at 0.25, 0.5, 1, 6, 12 and 24 h. Since the majority of CP-induced tumours are leukemias and lymphomas in the CBA/Ca mouse model, RNA was obtained from the thymus and the spleen. The results show that p53 is strongly expressed in the thymus during the focused period. On the other hand, the samples were subjected to in situ hybridisation and compared with the results of in situ hybridisation of lung and liver samples. Comparing the results of total RNA and in situ hybridisation should prove useful if the total RNA signal is too weak or not detectable at all. The in situ hybridisation picture showed many positive cells without high expression of oncogenes. Further flow-cytometric studies are necessary to provide a full explanation of the mechanism of CP induced changes. PMID: 9627803 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 668: Am J Pathol. 1998 Jun;152(6):1407-13. Bcl-2 and c-Myc, but not bax and p53, are expressed during human medullary thyroid tumorigenesis. Wang DG, Liu WH, Johnston CF, Sloan JM, Buchanan KD. Department of Medicine, School of Clinical Medicine, Queen's University of Belfast, United Kingdom. Medullary thyroid carcinoma (MTC) is a tumor of parafollicular cells of the thyroid gland. It has served as a useful experimental model for the study of tumor proliferation and differentiation. Although recent studies have identified the gene involved in familial forms of MTC, little is known about the molecular pathogenesis of the sporadic variants of this tumor. It has become increasingly clear that deregulation of programmed cell death is a critical component in multistep tumorigenesis. The present investigation was undertaken to determine whether similar molecular events occur in human MTC. Eighteen MTCs from 18 patients (including 12 sporadic and six familial cases and one metastatic lymph gland) and a MTC cell line (TT cells) were used in this study for detecting the expression of apoptosis-regulatory genes bcl-2, bax, c-myc, and p53. Immunohistochemical results showed that all MTC tumor samples displayed Bcl-2 and c-Myc immunoreactivity, whereas only 4 and 2 tumors showed a minority of cells positive for Bax and p53, respectively. Western and Northern blotting showed high levels of 26-kd Bcl-2 protein and bcl-2 transcript. The co-expression of Bcl-2 and c-Myc was also detected in the TT cells by indirect fluorescence immunohistochemistry and Western blotting. Moreover, Bcl-2 immunoreactivity was also found in C-cell hyperplasia from familial patients indicating that expression of this oncogene may represent an early event in the pathogenesis of MTC. The present study suggests that deregulation of programmed cell death may be a critical component in multistep tumorigenesis of MTC and that the frequent expression of the Bcl-2 oncoprotein in these tumors may contribute to their pathogenesis. The genetic complementation of simultaneously deregulated bcl-2 and c-myc may be implicated in the multistep tumorigenesis of human MTC. PMID: 9626044 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 669: Genes Chromosomes Cancer. 1998 Jul;22(3):225-31. Temporal differences in replication timing of homologous loci in malignant cells derived from CML and lymphoma patients. Amiel A, Litmanovitch T, Lishner M, Mor A, Gaber E, Tangi I, Fejgin M, Avivi L. Genetic Institute, Meir Hospital, Kfar Saba, Israel. A close association usually exists between replication timing of a given locus and its transcriptional activity: expressed loci replicate early whereas silent ones replicate late. Accordingly, alleles that show concomitant expression replicate synchronously, while those displaying an allele-specific mode of expression show temporal differences in their replication timing, i.e., they replicate asynchronously. We aimed in our study to see whether the cancer phenotype is accompanied by a relaxation in the temporal control of allelic replication. Fluorescence in situ hybridization (FISH) was used to determine the level of synchronization in replication timing of four pairs of homologous loci in samples of malignant cells derived from patients with chronic myeloid leukemia (CML) and lymphoma and in samples from healthy individuals. Four loci, HER2 mapped to 17q11.2-q12, a locus at 21q22, TP53 mapped to 17q13.1, and MYC mapped to 8q24 were studied. In each sample we analyzed two chromosomal regions, either 17q11.2-q12 and 21q22 or 17p13.1 and 8q24. The results showed distinct differences between healthy individuals and CML/lymphoma patients: all samples derived from noncancerous subjects showed high levels of synchrony in replication timing of alleles, whereas those of cancer patients displayed a large temporal difference in replication timing, indicating early and late replicating alleles. Thus, as judged by four unrelated loci, malignancy is associated with changes in the replication pattern of homologous loci. PMID: 9624534 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 670: J Pathol. 1998 Mar;184(3):247-51. Expression of Bcl-2 in lung neuroendocrine tumours: comparison with p53. Wang DG, Johnston CF, Sloan JM, Buchanan KD. Division of Medicine, School of Clinical Medicine, Queen's University of Belfast, U.K. Several genetic aberrations have been implicated in the carcinogenesis of small cell lung carcinomas (SCLCs), including tumour suppressor gene p53 deletion and mutation and amplification of the myc family proto-oncogenes. However, their exact ontogeny and carcinogenesis remain unknown. There are no proven aetiological factors for lung carcinoid tumours. Recent evidence suggests that the genetic regulation of apoptosis is of critical importance during tumourigenesis and that oncogene and tumour suppressor genes can regulate the rate, or susceptibility, of cells to undergo apoptosis. In this study, the expression of Bcl-2 protein has been investigated in 77 primary lung neuroendocrine tumours, including 55 SCLCs and 22 carcinoid tumours, and compared with p53 expression. Of the 77 tumours studied, Bcl-2 immunoreactivity was present in 80 per cent of SCLCs, 43 per cent of typical, and 67 per cent of atypical carcinoid tumours with more than 10 per cent tumour cell positivity. Western and Northern blot analysis revealed that carcinoid tumours expressed the 26 kD protein and bcl-2 transcripts. Whereas 42 per cent of the SCLCs studied displayed p53 protein immunoreactivity in more than 10 per cent of tumour cells, p53 positivity was not found in lung carcinoid tumours. There are statistical differences in Bcl-2 and p53 expression between SCLCs and lung carcinoid tumours. These results suggest that disregulation of the genetic mechanisms controlling apoptosis is a critical step in the progression of SCLC, and the expression of Bcl-2 is involved in the pathogenesis of SCLC and lung carcinoid tumours. The genetic complementation of simultaneously deregulated Bcl-2 and p53 may be implicated in the multistep tumourigenesis of small cell lung cancer. PMID: 9614375 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 671: Anticancer Res. 1998 Mar-Apr;18(2A):1149-52. Effect of ABVD therapeutic protocol on oncogene and tumor suppressor gene expression in CBA/Ca mice. Ember I, Kiss I, Ghodratollah N, Raposa T. Department of Preventive Medicine, University Medical School of Pecs, Hungary. The in vivo investigation of onco/suppressor gene effects may provide new information on chemical-environmental carcinogenesis. We previously described the elevation of onco/suppressor gene expression due to CHOP and COPP chemotherapeutical protocols in a CBA/Ca mouse model. Below we describe the results of the onco/suppressor gene expression studies after treatment with ABVD, a non-cyclophosphamide containing protocol. Expression of c-myc, Ha-ras, and p53 genes was investigated 1/2, 1, 3, 6, 12, 24 hours, 2 6 30 days, 6, and 12 months after treatment with a single dose of ABVD protocol. RNA was isolated from the thymus, spleen, liver, bone marrow, kidneys, and hybridzed with chemiluminescently labelled probes of Ha-ras, c-myc, and p53 genes. Significant changes of gene expression was found in the spleen and thymus, even after 30 minutes. The female spleen seemed to be more sensitive than the male one, but no sex difference was observed in the thymus. No significant alteration was detected in the other investigated organs. PMID: 9615780 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 672: Anticancer Res. 1998 Mar-Apr;18(2A):695-9. Spontaneous and radiation-induced apoptosis in lung carcinoma cells with different intrinsic radiosensitivities. Sirzen F, Zhivotovsky B, Nilsson A, Bergh J, Lewensohn R. Department of Oncology, Radiumhemmet, Karolinska Hospital, Stockholm, Sweden. Spontaneous and radiation-induced apoptosis in three lung carcinoma cell lines (U-1285, U-1906 and U-1810) with previously characterised intrinsic radiosensitivities (RS) was assessed by TUNEL-staining, detection of DNA laddering and cleavage of poly-(ADP-ribose) polymerase (PARP). Spontaneous apoptosis was detected at a high level in the radiosensitive U-1285, at an intermediate level in U-1906 and not detected in the radioresistant U-1810 cell line. Radiation-induced apoptosis, assessed by TUNEL assay, was present in U-1285 and U-1906 cells but not in U-1810 cells. To explain these findings, expression of Bcl-2, Bax, c-Myc and RB protein and mutations of the p53 gene were analysed. The ratio Bcl-2/Bax was higher in U-1810 cells compared with U-1285 and U-1906 cells. Overexpression of c-Myc and loss of RB was found in U-1285 cells whereas both U-1906 and U-1810 cells expressed RB and showed lower c-Myc expression. Analysis with sequencing of all p53 exons disclosed mutations in all three cell lines. Thus, apoptosis was a p53 independent process in U-1285 and U-1906 cells. RB loss and overexpression of c-Myc may enhance apoptosis in U-1285 cells. Our data suggest that spontaneous apoptosis may correlate with RS in SCLC. PMID: 9615707 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 673: Int J Cancer. 1998 May 29;76(5):639-46. Selective down-regulation of human papillomavirus transcription by 2-deoxyglucose. Maehama T, Patzelt A, Lengert M, Hutter KJ, Kanazawa K, Hausen H, Rosl F. Department of Obstetrics and Gynecology, School of Medicine, University of the Ryukyus, Japan. The glycolytic pathway inhibitor 2-deoxyglucose (2-DG) is capable of suppressing the transcription of the human pathogenic papillomavirus type 18 (HPV 18) in cervical carcinoma cells and derived non-tumorigenic somatic cell hybrids at the level of transcription initiation. HPV down-regulation is selective, since other reference genes are not affected or even up-regulated under the same experimental conditions. Moreover, 2-DG appears to restore the normal half-life of the tumor suppressor gene product p53, because the protein is strongly up-regulated after HPV 18 E6/E7 suppression. The observed 2-DG-effect is not cytotoxic and is reversible after refeeding with fresh medium. HPV 18 suppression by 2-DG can be completely abrogated by simultaneous treatment with the intracellular Ca2+ antagonist TMB-8, indicating that Ca2+, a known intracellular "second messenger", is involved in this process. Elevated c-myc and p53 expression appears to be responsible for the time-dependent accumulation of apoptotic cells after prolonged 2-DG treatment. The finding that 2-DG acts selectively against the expression of a human pathogenic papillomavirus strongly suggests that an appropriate level of glycolysis is not only a peculiarity of growing tumors, but even may be an essential prerequisite for the maintenance of virus-specific E6/E7 gene expression. Our results may have substantial implications for the potential therapeutic application of 2-DG or other glucose derivatives in the treatment of precancerous and malignant HPV-associated lesions. PMID: 9610719 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 674: Br J Haematol. 1998 May;101(2):311-7. Functional analysis of the p53 protein in AIDS-related non-Hodgkin's lymphomas and polymorphic lymphoproliferations. Martin A, Flaman JM, Frebourg T, Davi F, El Mansouri S, Amouroux J, Raphael M. Service d'Anatomie et Cytologie Pathologiques, Hopital Avicenne, Bobigny, France. Alteration of the tumour suppressor gene p53 is frequent in AIDS-related non-Hodgkin's lymphomas (AIDS-NHL), particularly in Burkitt's or Burkitt's-like lymphomas (BL/BLL). Since mechanisms of inactivation other than mutations have been advanced, the transcriptional activity of the p53 protein was studied in a functional assay in yeast in a series of AIDS-NHL lesions and compared with their morphology, immunohistochemistry (IHC) and single-strand conformation polymorphism (SSCP) analysis detection of other p53 abnormalities, Epstein-Barr virus (EBV) status, MDM-2 oncoprotein expression and c-MYC rearrangement. Polymorphic lymphoproliferations (PL), identified as precursors of NHL in HIV-patients, were also analysed in attempt to detect p53 modifications related to clonal progression. The functional assay detected p53 mutants in 40% (12/ 30) of the tumours: 50% (6/12) of BL/BLL, 40% (4/10) of diffuse large cell lymphomas (DLCL) and 25% (2/8) of PL. An oligoclonal or monoclonal population was identified in the two PL cases with mutant p53. An accumulation of the p53 protein was detected by IHC in 26% (8/30) of the tumours (five BL/BLL and three DLCL) and was associated with positive functional assay. In the 20 lesions tested by both of the screening methods for mutations, a p53 mutant pattern was detected in 55% of cases (11/20) and in 25% of cases (5/ 20) respectively with the functional assay and SSCP analysis of exons 5-8. There was no inverse correlation between the detection of EBV genome and the presence of p53 mutations and no overexpression of MDM-2 protein for the whole series. In conclusion, the functional assay was more sensitive than IHC and SSCP for the detection of p53 mutations in tumour samples. The mutations identified in AIDS-NHL lesions inactivate the p53 protein and in PL they could represent a selection of an aggressive clone. PMID: 9609527 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 675: Brain Res Mol Brain Res. 1998 May;56(1-2):133-45. Hippocampal Myc and p53 expression following transient global ischemia. McGahan L, Hakim AM, Robertson GS. Department of Pharmacology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada. The proto-oncogene c-myc, and the tumor suppressor gene p53, encode proteins which function as transcriptional regulating factors governing cell proliferation, differentiation, and apoptosis. Recent evidence suggests that the delayed neuronal death which follows an episode of transient forebrain ischemia may involve apoptotic processes. We have therefore utilized immunohistochemistry to investigate the effects of transient global ischemia on neuronal expression of p53- and Myc-like immunoreactivities in the rodent forebrain 2, 12, 24, 48, and 72 h following reperfusion. Transient global ischemia (20 min), produced by four vessel occlusion (4-VO), initially elevated p53-like immunoreactivity in both CA1 and CA3 hippocampal subfields at 24 h of recirculation. However, distinct patterns of gene expression became evident in these regions at later time points. A pivotal difference was the persistence of ischemia-induced increases of p53- and Myc-like immunoreactivity in the CA1 region of the hippocampus. Unlike CA3 neurons where p53-like immunoreactivity subsided to basal levels by 48 h of survival, CA1 neurons continued to display increased p53-immunoreactivity 48 h post-ischemia, while Myc-like immunoreactivity was selectively elevated in CA1 neurons at this time point. Ischemia-induced increases in p53-like immunoreactivity were also detected in vulnerable regions of the amygdala, thalamus, and cortex 12 to 48 h after recirculation. Given that both p53 and Myc have been implicated in gene signalling pathways which mediate programmed cell death, our findings which demonstrate that 4-VO produces persistent elevations of p53- and Myc-like immunoreactivities in vulnerable neurons suggest that these proteins may also contribute to delayed neuronal death following an episode of transient forebrain ischemia. Copyright 1998 Elsevier Science B.V. PMID: 9602097 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 676: Zhonghua Yi Xue Za Zhi. 1997 Mar;77(3):197-200. [Expression of apoptosis regulating proteins P 53, c-myc and bcl-2 on CD34+ hematopoietic cells isolated from human bone marrow] [Article in Chinese] Xi Y, Zhang S, Hao X. Department of Immunology, 307 Hospital, Academy of Military Medical Sciences, Beijing. OBJECTIVE: To show the coexpression levels of P 53, c-myc or bcl-2, three key apoptosis-regulating proteins on CD34+HC and bone marrow mononuclear cells (BMMNC). METHODS: IsolexTM50 or CIMS-100 systems of immunomagnetic bead separation and two-dimensional flow cytometric analysis of the immunofluorescence double staining were used. RESULTS: With 90%-95% purity of CD34+HC measured by FACS, we found that expression levels of P53, c-myc, and bcl-2 on both CD34+HC and BMMNC were as follows: CD34+/P53 + 0.1-00.8% versus BMMNC 0.1-0.6%; CD34+/c-myc+2.4%-11. 3% versus BMMNC 0.1-0.4%; CD34+/bcl-2+0.5-1.6% versus BMMNC 0.1-0.8%. Coexpression of c-myc and bcl-2 on CD34+HC was significantly higher than those observed on BMMNC respectively. CONCLUSION: It could be speculated that apoptosis-regulating proteins P53, c-myc and bcl-2 play a key role in the control of the survival, proliferation, differentiation, maturation and death in hematopoietic cells of physiological state, suggesting that these proteins balance the production numbers and quality of hematopoietic cells. PMID: 9596959 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 677: Chin Med J (Engl). 1997 Apr;110(4):250-4. Relationship of p53 alteration and myc family gene overexpression with the clinical characteristics of lung cancer. Bai L, Sun Y, Li S. Chinese Academy of Medical Science, Cancer Institute and Hospital, Beijing, China. OBJECTIVE: To evaluate the relationship of p53 alteration and myc family gene overexpression with the clinical characteristics of lung cancer. METHODS: A series of 59 resected primary lung cancer specimens was analyzed for p53 gene by DNA/PCR sequencing and immunohistochemistry technique, and for myc family genes by RT-PCR methods. RESULTS: Thirty-seven of 57 tumors were found to have p53 mutations or/and p53 protein accumulation. The presence of p53 alteration was not related to tumor size, lymph node metastasis, stage and relapse. Forty-seven cases were analyzed for myc family genes. The results showed that there was a positive correlation between unregulative expression of myc genes and the above mentioned clinical parameters. Our finding also showed that 19 of 30 cases (63%) with p53 alteration had myc gene overexpression which occurred in 63% and 76% cases with stage III and relapse, respectively, which was higher than 27% and 22% with p53 alteration but no myc gene overexpression and 50% and 71% with p53 negative but myc gene overexpression. CONCLUSIONS: p53 alteration is a vital genetic event in the earlier stage of lung carcinogenesis, but not a prognostic marker. myc family genes overexpression may be regarded as one of the independent prognostic determinants in lung cancer. The cooperation between p53 alteration and myc gene overexpression may occur during progression of lung cancer, but prognostic determinant is myc gene overexpression. PMID: 9594222 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 678: Gan To Kagaku Ryoho. 1998 Apr;25 Suppl 3:415-21. [Correlation between apoptotic index, bcl-2 protein expression and progression and prognosis in breast carcinoma] [Article in Japanese] Zhang GJ, Kimijima I, Watanabe T, Kanno M, Sagara H, Furukawa Y, Tsuchiya A, Abe R. Dept. of Surgery 2, Fukushima Medical College. Apoptosis is considered to play a critical role in tumorigenesis. It has been shown that apoptosis is controlled by both pro-oncogenes bcl-2, c-myc and tumor-suppressor genes p53. We determined the apoptotic index (AI) on light microscopy and detected immunohistochemically the expression of bcl-2 and p53 in patients with breast cancer. The correlations between AI and clinicopathological factors, bcl-2 and p53 were also analyzed. Our results showed that bcl-2 expression was down-regulated in the process from normal breast epithelial cells to intraductal carcinoma and from intraductal carcinoma to invasive carcinoma. We failed to detect p53 protein in normal breast epithelial cells, and p53 positivity was 24% and 30% in intraductal and invasive cancer tissues, respectively. Moreover, AI was significantly associated with histological grade, mitotic index, and bcl-2 and p53 expression. In univariate analyses, lower AI and bcl-2 expression was significantly predictive of a better prognosis for both disease-free survival and overall survival. These results suggest that apoptosis and apoptosis-related gene (bcl-2, p53) are related to progression and prognosis in breast cancer. PMID: 9589045 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 679: Pharmacol Ther. 1998 Feb;77(2):135-48. Molecular markers of carcinogenesis. Brandt-Rauf PW, Pincus MR. Division of Environmental Health Sciences, School of Public Health, Columbia University, New York, NY 10032, USA. The protein products of oncogenes and tumor suppressor genes play critical roles in the development of many cancers. The expression of a number of these proteins can be detected in extracellular fluids such as blood. This article reviews the literature on the application of methods for the detection of the proteins of oncogenes and tumor suppressor genes in the blood of humans with cancer or at risk for the development of cancer. The detection of these proteins in blood may be useful molecular markers of carcinogenesis that could play an important part in cancer diagnosis, prognosis, and prevention. Publication Types: Review Review, Tutorial PMID: 9578321 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 680: Haematologica. 1998 Mar;83(3):209-16. Detection of single and associated lesions of the Bcl-1, Bcl-2, Bcl-6, c-myc, p53 and p16 genes in B-cell non-Hodgkin's lymphomas: value of molecular analysis for a better assignment of the histologic subtype. Garcia-Sanz R, Vargas Montero M, Gonzalez Diaz M, del Carmen M, Santos C, Balanzategui Echevarria A, Flores Corral T, Hernandez Martin JM, Caballero Barrigon MD, San Miguel JF. Department of Hematology, Hospital Universitario De Salamanca, Spain. BACKGROUND AND OBJECTIVE: Molecular genetic abnormalities have been frequently described in non-Hodgkin's lymphomas (NHL). These lesions have been associated with specific entities, allowing a better categorization of NHL. However, these abnormalities are not as specific as initially described and their association is still unknown. DESIGN AND METHODS: By Southern blot and polymerase chain reaction, we have simultaneously analyzed the proto-oncogenes Bcl-1, Bcl-2, Bcl-6, c-myc and MLL and the tumor suppressor genes p53 and p16, in 100 unselected B-cell NHL patients at diagnosis, to establish its incidence throughout the different NHL subtypes, defined both by Working Formulation and REAL classifications, and to assess the frequency of co-existence of two or more genetic lesions within each individual patient. RESULTS: Fifty two cases displayed some genetic abnormality. Bcl-1, altered in 12 cases, was highly specific to mantle cell lymphomas (57% of them), but 6 cases had a different histologic subtype. Bcl-2 was rearranged in 26 cases: 70% in follicular lymphomas (FL) and 20% in diffuse large cell lymphomas; these abnormalities were also present in other subtypes, i.e. marginal lymphomas (30%). Bcl-6 abnormalities were mostly found in diffuse large cell lymphomas (29%) but also found in other subgroups, like FL (14%). C-myc rearrangements were specific to Burkitt's lymphoma. MLL gene was always germline. Deletions and/or rearrangements of p53 and p16 genes were rare (4% and 8% of all cases, respectively). Finally, association of genetic lesions was a relatively common finding (13% of cases), especially in cases with adverse prognostic morphologies according to the REAL. INTERPRETATION AND CONCLUSIONS: Molecular abnormalities are frequent in NHL at diagnosis, not only as unique lesions but also associated. A relative high specificity of some alterations was seen, thereby contributing to a better assessment of the histological subtype. Publication Types: Clinical Trial PMID: 9573674 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 681: Anticancer Res. 1998 Jan-Feb;18(1A):445-7. Effect of 7,12-dimethylbenz(a)anthracene on onco/suppressor gene action in vivo: a short-term experiment. Ember I, Kiss I, Pusztai Z. Department of Preventive Medicine, University Medical School of Pecs, Hungary. Dimethylbenz[a]anthracene is a pluripotent carcinogenic chemical, which acts as an initiator by causing point mutations in certain oncogenes and tumor suppressor genes. Changes in their expression may be another possible area of investigation the carcinogenic effect of DMBA. Elevated expression of oncogenes was previously has been shown after treatment with carcinogenic compounds. In the present study, expression of c-myc, c-Ha-ras and p53 24 hours after a single dose treatment of DMBA in the spleen and in the liver of Long-Evans rats was investigated. Control animals were injected with the solvent corn oil only. We could not find any significant change on the transcriptional level of the investigated oncogenes in the liver. In the spleen, the overexpression of Ha-ras was 2-fold and c-myc was 3-fold higher in the DMBA-treated rats than in the corresponding control group. Since DMBA is a typical environmental carcinogen, the results of animal experiments may serve as a basis for application of gene expression investigations as a screening method in humans. PMID: 9568117 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 682: Cancer Lett. 1998 Mar 13;125(1-2):17-23. Increased susceptibility of the c-Myc overexpressing cell line, SNU-16, to TNF-alpha. Park IC, Park MJ, Lee SH, Choe TB, Jang JJ, Hong SI. Laboratory of Cell Biology, Korea Cancer Center Hospital, Seoul, South Korea. Tumor necrosis factor-alpha (TNF-alpha) is a macrophage-derived multifunctional cytokine that acts as a cytostatic or cytotoxic agent in many tumor cells. However, the molecular mechanisms by which tumor cells become sensitive to the cytotoxic action of TNF-alpha are not clear. In this study we demonstrated that the cytotoxicity of TNF-alpha markedly increased in c-Myc overexpressing tumor cells. The stomach cancer cell line, SNU-16, in which c-Myc expression is high due to gene amplification, showed programmed cell death detected by DNA fragmentation and morphological changes. An antisense c-myc S-oligonucleotide specifically inhibited the TNF-alpha-induced apoptosis of SNU-16 cells, provided that the oligonucleotide was added 4 h prior to TNF-alpha treatment. Western immunoblot analysis of p53 and Bax showed that in this cell line, TNF-alpha increased the level of these proteins in a time-dependent manner and that this effect lasted for 12 h. Taken together these data indicate that the deregulation of c-Myc plays an important role in sensitizing tumor cells to TNF-alpha. Furthermore, TNF-alpha-induced apoptosis in the SNU-16 cell line showed increased expression of p53 and Bax protein levels following TNF-alpha treatment. Therefore, we suggest that TNF-alpha-induced apoptosis, which is cytotoxic to tumor cells, is coupled with a p53 and Bax apoptotic pathway. PMID: 9566690 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 683: Leukemia. 1998 Apr;12(4):542-53. V-myc in a simple, single gene retroviral vector causes rapid induction of leukemia and concomitant apoptosis following bone marrow transplantation. Dolnikov A, Shounan Y, Millington M, Mackenzie K, Symonds G. Department of Clinical Pharmacology and Toxicology, St Vincent's Hospital, Darlinghurst, Australia. We have previously developed an in vivo model of leukemogenesis utilizing mice reconstituted with genetically modified bone marrow cells. Based on those studies, a new single gene retroviral vector has been engineered which efficiently transfers v-myc into immature murine bone marrow cells. All reconstituted mice developed leukemia with a short latency period (5-11 weeks). In addition to hyperproliferation associated with elevated levels of PCNA, extensive apoptosis was also observed in all leukemic animals with p53 accumulating in the apoptotic cells. Whereas bax encoded protein, an effector of p53 apoptotic activity was detected in apoptotic cells, p21Waf1 protein, a potential mediator of p53 growth suppression was not detected in these cells suggesting that v-myc-induced apoptosis was independent of the ability of p53 to induce p21Waf1. These results indicate that apoptosis, a part of the cellular response to v-myc expression, does not prevent leukemia development and that hyperproliferation rather than abrogation of oncogene-induced apoptosis appears to be a critical event in v-myc-induced leukemia. PMID: 9557613 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 684: J Cell Biol. 1998 Mar 23;140(6):1307-20. Selective entrapment of extrachromosomally amplified DNA by nuclear budding and micronucleation during S phase. Shimizu N, Itoh N, Utiyama H, Wahl GM. Faculty of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 724, Japan. Acentric, autonomously replicating extrachromosomal structures called double-minute chromosomes (DMs) frequently mediate oncogene amplification in human tumors. We show that DMs can be removed from the nucleus by a novel micronucleation mechanism that is initiated by budding of the nuclear membrane during S phase. DMs containing c-myc oncogenes in a colon cancer cell line localized to and replicated at the nuclear periphery. Replication inhibitors increased micronucleation; cell synchronization and bromodeoxyuridine-pulse labeling demonstrated de novo formation of buds and micronuclei during S phase. The frequencies of S-phase nuclear budding and micronucleation were increased dramatically in normal human cells by inactivating p53, suggesting that an S-phase function of p53 minimizes the probability of producing the broken chromosome fragments that induce budding and micronucleation. These data have implications for understanding the behavior of acentric DNA in interphase nuclei and for developing chemotherapeutic strategies based on this new mechanism for DM elimination. PMID: 9508765 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 685: Cancer Surv. 1997;30:163-92. Cytogenetic mechanisms in the pathogenesis and progression of follicular lymphoma. Knutsen T. Cytogenetic Oncology Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. A summary of the clinically significant cytogenetic markers in follicular lymphoma is presented in Table 3. It is clear that the use of cytogenetic analysis to evaluate progression and transformation in follicular lymphoma is complicated by the variety and complexity of the chromosomal aberrations present in this disease. Cytogenetic and molecular studies have indicated that the t(14;18) translocation is the prerequisite of a multistep process in the lymphomagenesis of follicular lymphoma; it is usually followed by a long quiescent period during which the B cell population expands and additional oncogenic mutations occur leading to eventual progression and transformation to a highly malignant form. This process can be accomplished by a variety of pathways: Activation of other oncogenes by additional chromosomal rearrangements (e.g. MYC, LAZ3) Deletion and mutation of tumour suppressive genes (e.g. TP53, proposed genes on 6q) Gain of whole or parts of chromosomes, leading to increased expression of important regulating factors (e.g. MDR and T cell receptor genes on chromosome 7) More studies are required to determine which of these pathways, if any, is most important for neoplastic transformation. Publication Types: Review Review, Tutorial PMID: 9547992 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 686: Cancer Surv. 1997;30:21-44. Polymerase chain reaction in the assessment of lymphomas. Diss TC, Pan L. Department of Histopathology, UCL Medical School, London. The polymerase chain reaction (PCR) offers a practical means of studying the molecular genetic features of lymphomas. The method is rapid and, as formalin-fixed, paraffin processed samples can be used, does not require special tissue handling procedures. PCR amplified immunoglobulin and T cell receptor gene rearrangements can be exploited as markers of clonality and lineage and genetic abnormalities such as chromosome translocations and mutations of oncogenes and tumour suppressor genes can be used to identify specific lymphoma types. Polymorphic X linked loci may also be used as markers of clonality in females. Direct sequencing of PCR amplified IGH variable regions has provided insights into the developmental stages, susceptibility to antigen drive and dissemination patterns of lymphomas. The role of oncogenes and tumour suppressor genes such as MYC and TP53 in lymphomas can be studied by PCR amplification of mutation hotspots and direct sequencing of products. Known viral and bacterial DNA can readily be identified using PCR and unknown organisms sought using conserved primers to amplify polymorphic sequences. PCR analysis of the lymphomas and related disorders has accelerated our understanding of their molecular biology and provides a practical tool with diagnostic and prognostic applications. Future development of in situ PCR methods will provide cellular localization of genetic defects and infectious agents. Publication Types: Review Review, Tutorial PMID: 9547984 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 687: Brain Pathol. 1998 Apr;8(2):263-76. Frequent inactivation of CDKN2A and rare mutation of TP53 in PCNSL. Cobbers JM, Wolter M, Reifenberger J, Ring GU, Jessen F, An HX, Niederacher D, Schmidt EE, Ichimura K, Floeth F, Kirsch L, Borchard F, Louis DN, Collins VP, Reifenberger G. Department of Neuropathology, Heinrich-Heine-Universitat, Dusseldorf, Germany. Twenty primary central nervous system lymphomas (PCNSL) from immunocompetent patients (nineteen B-cell lymphomas and one T-cell lymphoma) were investigated for genetic alterations and/or expression of the genes BCL2, CCND1, CDK4, CDKN1A, CDKN2A, MDM2, MYC, RB1, REL, and TP53. The gene found to be altered most frequently was CDKN2A. Eight tumors (40%) showed homozygous and two tumors (10%) hemizygous CDKN2A deletions. Furthermore, methylation analysis of six PCNSL without homozygous CDKN2A loss revealed methylation of the CpG island within exon 1 of CDKN2A in three instances. Reverse transcription PCR analysis of CDKN2A mRNA expression was performed for 11 tumors and showed either no or weak signals. Similarly, immunocytochemistry for the CDKN2A gene product (p16) remained either completely negative or showed expression restricted to single tumor cells. None of the PCNSL showed amplification of CDK4. Similarly, investigation of CCND1 revealed no amplification, rearrangement or overexpression. The retinoblastoma protein was strongly expressed in all tumors. Only one PCNSL showed a mutation of the TP53 gene, i.e., a missense mutation at codon 248 (CGG to TGG:Arg to Trp). No evidence of BCL2 gene rearrangement was found in 11 tumors investigated. The bcl-2 protein, however, was strongly expressed in most tumors. None of the 20 PCNSL demonstrated gene amplification of MDM2, MYC or REL. In summary, inactivation of CDKN2A by either homozygous deletion or DNA methylation represents an important molecular mechanism in PCNSL. Mutation of the TP53 gene and alterations of the other genes investigated appear to be of minor significance in these tumors. PMID: 9546285 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 688: Oncol Rep. 1998 Jan-Feb;5(1):49-52. c-myc, c-erb-B2, nm23 and p53 expression in human endometriosis. Schneider J, Jimenez E, Rodriguez F, del Tanago JG. Hospital de Cruces, Departamento de Ginecologia, Baracaldo, Spain. We studied the expression of oncogenes and tumor-suppressor genes in human endometriosis in a retrospective pilot study. Sixteen patients with histologically verified pelvic endometriosis at the university-based tertiary care referral center were studied. Immunohistochemical determination of c-myc, c-erb-B2, nm23 and p53 expression in archival, paraffin-embedded pathological samples were used from patients operated upon for pelvic endometriosis. c-myc was expressed in 8/15 cases (53.3%). nm23 was expressed in 7/16 cases (43.7%). c-erb-B2 and p53 reactivity was undetectable in the samples studied. The c-myc oncogene and nm23 are overexpressed in many cases of endometriosis, and may play a still undefined role in its pathogenesis. Immuno-histochemistry is a useful tool for the study of oncogenic activation in this disease. PMID: 9458291 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 689: J Biol Chem. 1998 Feb 13;273(7):4197-205. Fibroblast variants nonresponsive to fibroblast growth factor 1 are defective in its nuclear translocation. Mehta VB, Connors L, Wang HC, Chiu IM. Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA. Fibroblast growth factors (FGF) elicit biological effects by binding to high affinity cell-surface receptors and activation of receptor tyrosine kinase. We previously reported that two NIH/3T3 derivatives, NR31 and NR33 (NR cells), express high levels of full-length FGF-1 and exhibit a complete spectrum of transformed phenotype. In the present study, we report that NR cells respond to the mitogenic stimulation of truncated FGF-1 but not to the full-length FGF-1. Incubation of the NR cells with either form of FGF-1 resulted in its binding to cell-surface FGF receptors, activation of mitogen-activated protein (MAP) kinase, and induction of c-fos and c-myc. These data demonstrate that the FGF receptor-mediated, MAP kinase-dependent signaling pathway is not defective in the NR cells. Our data further suggest that the activation of MAP kinase in response to full-length FGF-1 is not sufficient for mitogenesis. Subcellular distribution of exogenously added FGF-1 demonstrated that full-length FGF-1 fails to translocate to the nuclei of NR31 cells. Although the full-length FGF-1 was detected in the nuclear fractions of both NIH/3T3 and NR33 cells, its half-life is much shortened in NR33 than in NIH/3T3 cells. These observations suggest that non-responsiveness of the two NR cell lines may be due to defectiveness at different steps of nuclear translocation mechanism of FGF-1. PMID: 9461616 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 690: Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1511-6. A unique glucose-dependent apoptotic pathway induced by c-Myc. Shim H, Chun YS, Lewis BC, Dang CV. Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. The lactate dehydrogenase A (LDH-A) gene, whose product participates in normal anaerobic glycolysis and is frequently increased in human cancers, has been identified as a c-Myc-responsive gene. It was of interest, therefore, to compare the effect of glucose deprivation in c-Myc-transformed and nontransformed cells. We observed that glucose deprivation or treatment with the glucose antimetabolite 2-deoxyglucose caused nontransformed cells to arrest in the G0/G1 phase of the cell cycle. In contrast, c-Myc-transformed fibroblasts, lymphoblastoid, or lung carcinoma cells underwent extensive apoptosis. Ectopic expression of LDH-A alone in Rat1a fibroblasts was sufficient to induce apoptosis with glucose deprivation but not with serum withdrawal, suggesting that LDH-A mediates the unique apoptotic effect of c-Myc when glycolysis is blocked. The apoptosis caused by glucose deprivation was blocked by Bcl-2 expression but appeared to be independent of wild-type p53 activity. These studies provide insights on the coupling of glucose metabolism and the cell cycle in c-Myc-transformed cells and may in the future be exploited for cancer therapeutics. PMID: 9465046 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 691: Mol Carcinog. 1998 Feb;21(2):100-10. Carcinogenic alterations in murine liver, lung, and uterine tumors induced by in utero exposure to ionizing radiation. Lumniczky K, Antal S, Unger E, Wunderlich L, Hidvegi EJ, Safrany G. Department of Molecular Radiobiology, National Research Institute for Radiobiology and Radiohygiene, Budapest, Hungary. The atomic bombing of Hiroshima and Nagasaki and the nuclear accident at Chernobyl raised the question of prenatal sensitivity to ionizing radiation-induced cancer. In this study, mice were exposed to single doses of gamma-radiation (0.2-2.0 Gy) at different embryonic stages. The tumor incidence increased with dose from 15% in control mice to 35% in mice irradiated with 2.0 Gy on 18 d of prenatal life. Various oncogenic events were investigated in lymphoid, liver, lung, and uterine tumors. We observed threefold to fivefold increases in myc expression in 25% of the lymphomas, and the expression of Ha-ras and p53 genes decreased in 40% and 60% of the lung tumors by twofold to fivefold. Point mutations were tissue specific: Ha-ras codon 61 mutations were found in about 40% of the liver adenocarcinomas, Ki-ras codon 12 mutations in about 17% of lung tumors, and p53 mutations in about 15% of the lymphomas. Amplification and rearrangement of the p53, myc, and Ha-, Ki- and N-ras genes were not detected. Loss of heterozygosity on chromosome 4 at the multiple tumor suppressor 1 and 2 genes was observed in all types of malignancies. Allelic losses on chromosome 11 at the p53 locus were found in lymphoid, liver, and lung tumors, but they were absent from uterine tumors. Multiple oncogenic changes were often detected. The frequency of carcinogenic alterations was similar in spontaneous and radiation-induced lymphoid, liver, and uterine tumors. In radiation-induced lung adenocarcinomas, however, the incidences of many oncogenic changes were different from those found in their spontaneous counterparts. This suggests that different oncogenic pathways are activated during spontaneous and in utero gamma-radiation-induced murine lung carcinogenesis. PMID: 9496910 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 692: Cell Growth Differ. 1998 Feb;9(2):165-76. Cell cycle gene regulation in reversibly differentiated new human hepatoma cell lines. Glaise D, Ilyin GP, Loyer P, Cariou S, Bilodeau M, Lucas J, Puisieux A, Ozturk M, Guguen-Guillouzo C. INSERM U49, Hopital Pontchaillou, Rennes, France. Several novel differentiated cell lines have been derived from a human hepatocarcinoma named HBG. Analysis of their functional properties evidenced a gradual differentiation process as they became confluent and a remarkable stability of the whole quiescent population for at least 6 weeks. However, when replated at low density after several weeks of quiescence, the differentiated cells were able to rapidly reverse to active proliferation, accompanied by transient dedifferentiation. Demonstration that the differentiated hepatic cells were growth-arrested in G1 phase was provided by the increased number of cells with 2C DNA content and decreased expression of S-phase markers. Characteristic features of oncogenes and cell cycle genes were defined during the differentiation process: (a) a biphasic expression of c-myc, with the latter wave covering the quiescence period; (b) opposite kinetics of c-Ki-ras and of N-ras expression with a pattern of changes paralleling that of c-myc; and (c) a decrease of cyclin D1 protein expression and of the cyclin D1-associated kinase activity. The mechanisms by which quiescent differentiated cells might reinitiate active proliferation were analyzed by studying several genes involved in cell growth and death regulation. We found: (a) a point mutation and loss of the specific activity of the tumor suppressor gene p53 without alteration of the apoptotic response to transforming growth factor beta1; (b) a gradual decrease of retinoblastoma protein, which was constantly present, mainly in a hyperphosphorylated form; and (c) an increase of cyclin-dependent kinase inhibitor p27 expression in confluent differentiating cells, as expected, whereas, surprisingly, a disappearance of the p21 protein was observed in parallel. These data may reflect specific mechanisms of cell cycle regulation in liver parenchymal cells through which these cells can proceed to control their reversible differentiation program. PMID: 9486853 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 693: Arkh Patol. 1997 Nov-Dec;59(6):18-23. [Immunohistochemistry of biomolecular markers of early thyroid cancer] [Article in Russian] Paltsev MA, Kogan EA, Tuntsova OI. I.M. Sechenov Moscow Medical Academy. Surgery material from 28 cases was studied. Thyroid adenoma differs from thyroid carcinoma by a lower level of expression of Ki-67 and bcl-2, while the mutated p53 expression is lacking. These indices may be used for early and differential diagnosis of thyroid carcinoma. Medullary carcinoma is a tumor with the highest malignant potential and p53 and bcl-2 may serve as markers of a higher degree of malignancy. Ki-67 may serve a marker of proliferative activity of tumors belonging to the same histological type. Thus, its high expression in follicular carcinoma is an index of a high proliferative activity of its cells, correlates with its rapid growth and should be taken into consideration in therapy and prognosis. Expression of bcl-2 clearly correlates with neuroendocrine differentiation of carcinoma and its highest expression was found in the medullary carcinoma as well as in the chromogranin positive cells of the papillary thyroid carcinoma. APUD amyloid deposits in medullary carcinoma and high levels of c-myc in adenomas indicate some genetic restructurizations in malignant and benign thyroid tumors. PMID: 9483213 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 694: Int J Urol. 1997 Nov;4(6):552-6. Prognostic markers of intravesical bacillus Calmette-Guerin therapy for multiple, high-grade, stage T1 bladder cancers. Lee E, Park I, Lee C. Department of Urology, Seoul National University College of Medicine, Korea. BACKGROUND: Prediction of a response to intravesical bacillus Calmette-Guerin (BCG) therapy for bladder cancer is clinically important. We determined whether several molecular markers have prognostic value in intravesical BCG therapy for multiple, high-grade, stage T1 bladder cancers. METHODS: The expressions of p53 (clone D07), bcl-2 (100-D5), cathepsin-D (C5), c-myc(9E11), c-erbB-2 (CB11) and Ki-67 (MM1) were determined by immunohistochemistry in paraffin-embedded tissues from 32 multiple, T1, grade II-III bladder cancer patients (15 BCG responders, 17 nonresponders) who had undergone a single course of BCG therapy (Pasteur strain, 5 x 10(8) CFU weekly for 6 weeks) after complete removal of the tumors. The association between the expression of these markers and the response to BCG was assessed by univariate and multivariate analyses. RESULTS: There was no difference in patient and tumor characteristics between the 2 groups. Using multivariate analysis, the only useful marker was p53, with the overexpression of the p53 protein inversely related to the response to BCG therapy (P = 0.0182). CONCLUSION: Our results suggest that the status of p53 expression offers significant clinical information and may be a useful tool in the selection of suitable candidates for BCG therapy in multiple, high-grade stage T1 bladder cancer patients. PMID: 9477182 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 695: Heart Vessels. 1997;Suppl 12:76-80. Regulation of programmed cell death or apoptosis in atherosclerosis. Geng YJ. Cardiovascular and Pulmonary Research Institute, Allegheny University of the Health Sciences, Pittsburgh, PA 15212, USA. Intimal thickening caused by accumulation of cells, lipids, and connective tissue characterizes atherosclerosis, an arterial disease that leads to cardiac and cerebral infarction. Apoptosis, or genetically programmed cell death, is important for the development and morphogenesis of organs and tissues. As in other tissues, cells of cardiovascular tissues can undergo apoptosis. Increased apoptosis has been found in both human and animal atherosclerotic lesions, mediating tissue turnover and lesion development. In addition to vascular cells, many activated immune cells, mainly macrophages and T cells, are present in atherosclerotic lesions, where these cells produce biologically active substances such as the proinflammatory cytokines tumor necrosis factor, interleukin-1 (IL-1), and interferon-gamma. Simultaneous exposure to these cytokines may trigger apoptosis of vascular smooth muscle cells. The products of death-regulating genes including Fas/Fas ligand, members of IL-1 beta cysteinyl protease (caspase) family, the tumor suppressive gene p53, and the protooncogene c-myc have been found in vascular cells and may participate in the regulation of vascular apoptosis during the development of atherosclerosis. Abnormal occurrence of apoptosis may take place in atherosclerotic lesions, including attenuation or acceleration of the apoptotic death process. The former may cause an increase in the cellularity of the lesions, and the latter can reduce cellular components important for maintaining the integrity and stability of the plaques. Clarification of the molecular mechanism that regulates apoptosis may help design a new strategy for treatment of patients with atherosclerosis and its major complications, heart attack and stroke. Publication Types: Review Review, Tutorial PMID: 9476549 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 696: EMBO J. 1997 Dec 15;16(24):7382-92. Induction of TNF-sensitive cellular phenotype by c-Myc involves p53 and impaired NF-kappaB activation. Klefstrom J, Arighi E, Littlewood T, Jaattela M, Saksela E, Evan GI, Alitalo K. Molecular/Cancer Biology Laboratory, Haartman Institute, PO Box 21, 00014 University of Helsinki, Finland. Normal fibroblasts are resistant to the cytotoxic action of tumor necrosis factor (TNF), but are rendered TNF-sensitive upon deregulation of c-Myc. To assess if oncoproteins induce the cytotoxic TNF activity by modulating TNF signaling, we investigated the TNF-elicited signaling responses in fibroblasts containing a conditionally active c-Myc protein. In association with cell death, c-Myc impaired TNF-induced activation of phospholipase A2, JNK protein kinase and cell survival-signaling-associated NF-kappaB transcription factor complex. The TNF-induced death of mouse primary fibroblasts expressing deregulated c-Myc was inhibited by transient overexpression of the p65 subunit of NF-kappaB, which increased NF-kappaB activity in the cells. Unlike other TNF-induced signals, TNF-induced accumulation of the wild-type p53 mRNA and protein was not inhibited by c-Myc. TNF, with c-Myc, induced apoptosis in mouse primary fibroblasts but only weakly in p53-deficient primary fibroblasts. The C-terminal domain of p53, which is a transacting dominant inhibitor of wild-type p53, failed to inhibit apoptosis by c-Myc and TNF, suggesting that the cell death was not dependent on the transcription-activating function of p53. Taken together, the present findings show that the cytotoxic activity of TNF towards oncoprotein-expressing cells involves p53 and an impaired signaling for survival in such cells. PMID: 9405367 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 697: Oncogene. 1998 Jan 22;16(3):387-98. Involvement of CPP32/Caspase-3 in c-Myc-induced apoptosis. Kangas A, Nicholson DW, Holtta E. Haartman Institute, Department of Pathology, University of Helsinki, Finland. c-Myc is a transcriptional activator implicated in the control of cell proliferation, differentiation and transformation, but is also involved in the regulation of programmed cell death, apoptosis. Despite intensive research, the molecular mechanisms by which c-Myc triggers and executes cell death remain still elusive. Here, we made use of Rat 1A MycER cells expressing a conditionally active c-Myc protein and tested first the hypothesis that ornithine decarboxylase (ODC), which is a transcriptional target of c-Myc, were a mediator of c-Myc-induced apoptosis. However, our results show that the activity of ODC is not required for the c-Myc-mediated apoptosis to occur in these cells. We also found that the expression of p53, p21waf1/cip1, Bcl-2, Bax, Bcl-xL, Bad and cyclins D1, E, A and B did not show any significant changes following c-Myc induction. But, our studies revealed that the c-Myc induced apoptosis is associated with a specific cleavage of poly(ADPribose) polymerase (PARP), suggesting that a cysteine protease of the ICE/CED-3 family is involved. Moreover, we found that the cysteine protease CPP32/Caspase-3, which is known to cleave PARP, is processed from its inactive form to an active protease composed of 17 and 12 kDa subunits; whilst Ich-1/Caspase-2 belonging to another subset of this protease family was not processed/ activated following c-Myc activation. The activation of CPP32 and apoptotic cell death were inhibited by addition of Z-VAD-fmk, a universal inhibitor of ICE-like proteases. Further, a selective inhibitor of CPP32-like proteases (Z-DEVD-fmk) partly inhibited apoptosis. These results provide evidence that the ICE/CED3-family proteases, CPP32 and likely others, play a critical role in the execution of a nuclear proto-oncogene, c-Myc-induced apoptosis. PMID: 9467964 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 698: Arch Esp Urol. 1997 Oct;50(8):855-66. [The molecular biology of bladder carcinoma] [Article in Spanish] Moreno Sierra J, Maestro de las Casas ML, Chicharro Almarza J, Ortega Heredia MD, Lopez Garcia-Asenjo J, Merino Sanchez C, Blanco Jimenez E, Silmi Moyano A, Rsesel Estevez L. Catedra de Urologia, Hospital Clinico San Carlos, Madrid, Espana. OBJECTIVE: The clinical course of transitional cell carcinoma of the bladder can be difficult to predict due to its potential to invade the muscle layer and/or develop to a high grade lesion. Bladder carcinoma can arise from genetic changes that may activate the oncogenes (-c-erbB2, c-erbB1, c-myc, ras, etc.) and/or inactivate the suppressor genes (p53, Rb). The aim of the present study is to continue a study protocol on the molecular biology of bladder tumors. METHODS/RESULTS: From January, 1993 to January, 1995, 85 patients were studied. These patients were divided into two groups: the first group comprised 14 controls of urothelial tissue and the second comprised 65 cases of transitional cell carcinoma of the bladder. p53 expression was determined by an immunohistochemical method (NCL-p53-DO7 monoclonal antibody). Quantification of the p8 oncoprotein in cytosol and EGFR (epidermal growth factor receptor) in membrane was performed by ELISA (Oncogene Science) and RIA (Vienna Lab), respectively. A statistically significant relationship between the expression of p53 and EGFR with tumor stage and grade was found. Quantification of p185 and EGFR showed higher values in the tumor tissue than in the control samples, but a worse survival could not be determined. CONCLUSIONS: The present study shows that p53 expression can be considered to be a prognostic factor. It provides useful information on the aggressive behaviour of the tumor and has a direct relation with the survival rates. PMID: 9463283 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 699: Kidney Int. 1998 Feb;53(2):350-7. Morphine modulates proliferation of kidney fibroblasts. Singhal PC, Sharma P, Sanwal V, Prasad A, Kapasi A, Ranjan R, Franki N, Reddy K, Gibbons N. Department of Medicine, Long Island Jewish Medical Center, New Hyde Park, New York 11040, USA. Renal interstitial scarring is an important component of heroin-associated nephropathy. Kidney fibroblasts have been demonstrated to play a role in the development of renal scarring in a variety of renal diseases. We studied the effect of morphine, an active metabolite of heroin, on the proliferation of kidney fibroblasts. Morphine at a concentration of 10(-12) M enhanced (P < 0.001) the proliferation of kidney fibroblasts (control, 67.5 +/- 2.0 vs. morphine, 112.2 +/- 10.1 x 10(4) cells/well). [3H]thymidine incorporation studies further confirmed these results. Morphine at concentrations of 10(-12) M to 10(-10) M also modulated mRNA expression of early growth related genes (c-fos, c-jun and c-myc). Morphine at concentrations of 10(-8) to 10(-4) M promoted apoptosis of kidney fibroblasts and also enhanced the synthesis of p53 by kidney fibroblasts. We speculate that morphine-induced kidney fibroblast proliferation may be mediated through the activation of early growth related genes, whereas morphine induced kidney fibroblast apoptosis may be mediated through the generation of p53. The present in vitro study provides a hypothetical basis for the role of morphine in the development of renal interstitial scarring in patients with heroin-associated nephropathy. PMID: 9461094 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 700: Cancer Lett. 1997 Dec 9;120(2):235-41. Capsaicin can alter the expression of tumor forming-related genes which might be followed by induction of apoptosis of a Korean stomach cancer cell line, SNU-1. Kim JD, Kim JM, Pyo JO, Kim SY, Kim BS, Yu R, Han IS. Department of Biology, University of Ulsan, South Korea. Capsaicin (CAP) has been known to inhibit some tumor development in vivo (J.J. Jang, S.H. Kim, T.K. Yun, Inhibitory effect of capsaicin on mouse lung tumor development, in vivo, J. Korean Med. Sci. 3 (1989) 49-53; J.J. Jang, K.J. Cho, Y.S. Lee, J.H. Bae, Different modifying responses of capsaicin in a wide-spectrum initiation model of F344 rat, J. Korean Med. 6 (1991) 31-36) [1,2] even though its mechanism of action is not well understood. The objectives of this study were to examine the effect of CAP on expression of tumor forming-related genes in a Korean stomach tumor cell, SNU-1. We used slot blot hybridization to investigate its effect on a wide spectrum of proto-oncogenes. It was found that CAP enhanced the transcripts of two proto-oncogenes (c-myc and c-Ha-ras) and tumor suppressor gene p53. While a low concentration of CAP (0.01 microM) did not significantly increase the level of p53 transcript in SNU-1, it did increase it by a factor of 3.5 at a 10 microM dose of CAP. Consequently, SNU-1 cells are sensitive to CAP in the overexpression of tumor suppressor gene, p53 and proto-oncogenes, c-myc and c-Ha-ras, but not those of c-erbB-2, c-jun and bcl-2 genes. Both cell death and DNA fragmentation were shown in SNU-1 cells with treatment of CAP. Our results suggest that CAP induces apoptotic cell death in human gastric cancer cells (SNU-1) in vitro which may be possibly mediated by the overexpression of p53 and/or c-myc genes. Because cell suicide is arguably the most potent natural defense against cancer, the correlation between the induction of apoptosis and the change of tumor forming-related gene expression after CAP treatment should be further studied in detail. PMID: 9461043 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 701: Int J Oncol. 1998 Feb;12(2):299-304. Role of p53 and apoptosis in sensitization of cis-diamminedichloroplatinum antitumor activity by interleukin-1 in ovarian carcinoma cells. Song K, Fukushima P, Seth P, Sinha BK. Developmental Therapeutics Department, Medicine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. We have previously reported that interleukin-1 (IL-1 ) sensitized cisplatin cytotoxicity against human ovarian NIH:OVCAR-3 tumor cells. We have further examined inter-actions of IL-1 with cisplatin in these ovarian cells. Treatment of cells with either IL-1 or CDDP or combinations resulted in a significant accumulation of cells in G1 phase and a concomitant decrease in the S phase of the cell cycle. IL-1 and CDDP treatment induced p53 protein in NIH:OVCAR-3 tumor cells. CDDP and IL-1 treatment decreased the steady-state expression of c-myc RNA and induced significant degradation of the genomic DNA into internucleosomal sized DNA fragments which was further increased in the presence of both agents in these cells. Taken together, these studies suggest that IL-1 may kill ovarian NIH:OVCAR-3 tumor cells by inducing a blockade at G1/S of the cell cycle, down-regulating c-myc gene and inducing p53-dependent apoptosis. The synergistic interactions of IL-1 with CDDP may involve the enhancement of p53-dependent apoptosis. PMID: 9458352 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 702: J Biol Chem. 1998 Jan 2;273(1):381-5. X-gene product of hepatitis B virus induces apoptosis in liver cells. Kim H, Lee H, Yun Y. Signal Transduction Laboratory, Mogam Biotechnology Research Institute, 341 Pojungri, Koosungmyon, Yonginsi, Kyunggido 449-910, Korea. Hepatitis B virus is a causative agent of hepatocellular carcinoma, and in the course of tumorigenesis, the X-gene product (HBx) is known to play important roles. Here, we investigated the transforming potential of HBx by conventional focus formation assay in NIH3T3 cells. Cells were cotransfected with the HBx expression plasmid along with other oncogenes including Ha-ras, v-src, v-myc, v-fos, and E1a. Unexpectedly, the introduction of HBx completely abrogated the focus-forming ability of all five tested oncogenes. In addition, the cotransfection of Bcl-2, an apoptosis inhibitor, reversed the HBx-mediated inhibition of focus formation, suggesting that the observed repression of focus formation by HBx is through the induction of apoptosis. Next, to test unequivocally whether HBx induces apoptosis in liver cells, we established stable Chang liver cell lines expressing HBx under the control of a tetracycline-inducible promoter. Induction of HBx in these cells in the presence of 1% calf serum resulted in typical apoptosis phenomena such as DNA fragmentation, nuclear condensation, and fragmentation. Based on these results, we propose that HBx sensitizes liver cells to apoptosis upon hepatitis B virus infection, contributing to the development of hepatitis and the subsequent generation of hepatocellular carcinoma. PMID: 9417092 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 703: J Cell Biochem. 1998 Feb 1;68(2):139-50. Disruption of a putative SH3 domain and the proline-rich motifs in the 53-kDa substrate of the insulin receptor kinase does not alter its subcellular localization or ability to serve as a substrate. Yeh TC, Li W, Keller GA, Roth RA. Department of Molecular Pharmacology, Stanford University School of Medicine, California 94305, USA. The recently identified 53-kDa substrate of the insulin receptor family was further characterized in several retroviral-generated stable cell lines overexpressing the wild type and various mutant forms of the protein. To facilitate the study of its subcellular localization in NIH3T3 cells overexpressing insulin receptor, a myc epitope-tag was added to the carboxy terminus of the 53-kDa protein. Like the endogenous protein in Chinese hamster ovary cells, the expressed myc-tagged 53-kDa protein was found partially in the particulate fraction and was tyrosine phosphorylated in insulin-stimulated cells. Immunofluorescence studies showed for the first time that a fraction of the 53-kDa protein was localized to the plasma membrane. Confocal microscopy of cells double-labeled with antibodies to the insulin receptor and the myc epitope showed the two proteins co-localize at the plasma membrane at the level of light microscopy. Further analyses of the protein sequence of the 53-kDa substrate revealed the presence of a putative SH3 domain and two proline-rich regions, putative binding sites for SH3 and WW domains. Disruption of these three motifs by the introduction of previously characterized point mutations did not affect the membrane localization of the 53-kDa protein, its ability to serve as substrate of the insulin receptor, or its colocalization with the insulin receptor, suggesting these domains are not important in the subcellular targeting of the protein and instead may function in the interaction with subsequent signaling proteins. PMID: 9443070 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 704: Clin Immunol Immunopathol. 1998 Jan;86(1):59-71. Gender and androgen treatment influence the expression of proto-oncogenes and apoptotic factors in lacrimal and salivary tissues of MRL/lpr mice. Toda I, Wickham LA, Sullivan DA. Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114, USA. The objectives of this study were to (1) determine whether Fas antigen, Fas ligand, p53, and proto-oncogene mRNAs may be detected in lacrimal and submandibular glands of the MRL/lpr mouse model of Sjogren's syndrome, and (2) examine whether gender and androgen or cyclophosphamide therapy influence the mRNA expression of these apoptotic factors. Tissues were obtained from treated or untreated MRL/lpr mice after the onset of disease and processed for the analysis of mRNAs by RT-PCR and Southern blot hybridization. Our results demonstrated that (1) Fas antigen (exons 1-->2 or 3-->7+), Fas ligand, c-myb, c-myc, bcl-2, Bax, p53, and androgen receptor (AR) mRNAs are present in exocrine tissues of MRL/lpr mice; (2) the amounts of c-myb, c-myc, bcl-2, p53, and AR mRNA are higher (P < 0.05) and the level of Fas antigen (exons 1-->2) mRNA is lower (P < 0.05) in lacrimal glands of female compared to male mice. In contrast, the content of c-myb and p53 mRNA is greater (P < 0.05) in submandibular tissues of female relative to those of male mice; and (3) testosterone or cyclophosphamide treatment led to a significant (P < 0.05) decline in the mRNA levels of c-myb, bcl-2, and/or AR, but an increase (P < 0.05) in the mRNA amount of Bax, in lacrimal, but not in salivary, glands of female mice. These findings demonstrate that gender-associated differences exist in the expression of apoptotic factor mRNAs in exocrine tissues of autoimmune mice and that some of these differences appear to be due to the influence of androgens. PMID: 9434797 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 705: In Vivo. 1997 Sep-Oct;11(5):399-402. In vivo effects of COPP protocol on onco- and suppressor gene expression in a 'follow up study'. Ember I, Kiss I, Raposa T. Department of Preventive Medicine, University Medical School of Pecs, Hungary. In vivo investigation of onco or suppressor genes may provide new information concerning chemical carcinogenesis. In earlier studies we illustrated the carcinogenic potential of COPP chemotherapeutical protocol in "long term" experiments. Elevated expression of oncogenes was shown as soon as 24 hours after treatment in CBA/Ca inbred mice, in "short term" experiments. Now we present the results of the follow-up study dealing with the carcinogenic effect of COPP. The genes most frequently involved were N-ras and p53, with the thymus being the target organ of COPP. PMID: 9427043 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 706: Mol Cell Biol. 1998 Jan;18(1):536-45. MYC abrogates p53-mediated cell cycle arrest in N-(phosphonacetyl)-L-aspartate-treated cells, permitting CAD gene amplification. Chernova OB, Chernov MV, Ishizaka Y, Agarwal ML, Stark GR. Department of Molecular Biology, Research Institute, The Cleveland Clinic Foundation, Ohio 44195, USA. Genomic instability, including the ability to undergo gene amplification, is a hallmark of neoplastic cells. Similar to normal cells, "nonpermissive" REF52 cells do not develop resistance to N-(phosphonacetyl)-L-aspartate (PALA), an inhibitor of the synthesis of pyrimidine nucleotides, through amplification of cad, the target gene, but instead undergo protective, long-term, p53-dependent cell cycle arrest. Expression of exogenous MYC prevents this arrest and allows REF52 cells to proceed to mitosis when pyrimidine nucleotides are limiting. This results in DNA breaks, leading to cell death and, rarely, to cad gene amplification and PALA resistance. Pretreatment of REF52 cells with a low concentration of PALA, which slows DNA replication but does not trigger cell cycle arrest, followed by exposure to a high, selective concentration of PALA, promotes the formation of PALA-resistant cells in which the physically linked cad and endogenous N-myc genes are coamplified. The activated expression of endogenous N-myc in these pretreated PALA-resistant cells allows them to bypass the p53-mediated arrest that is characteristic of untreated REF52 cells. Our data demonstrate that two distinct events are required to form PALA-resistant REF52 cells: amplification of cad, whose product overcomes the action of the drug, and increased expression of N-myc, whose product overcomes the PALA-induced cell cycle block. These paired events occur at a detectable frequency only when the genes are physically linked, as cad and N-myc are. In untreated REF52 cells overexpressing N-MYC, the level of p53 is significantly elevated but there is no induction of p21waf1 expression or growth arrest. However, after DNA is damaged, the activated p53 executes rapid apoptosis in these REF52/N-myc cells instead of the long-term protective arrest seen in REF52 cells. The predominantly cytoplasmic localization of stabilized p53 in REF52/N-myc cells suggests that cytoplasmic retention may help to inactivate the growth-suppressing function of p53. PMID: 9418900 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 707: Arch Ital Urol Androl. 1997 Sep;69(4):271-7. [Molecular biology in bladder carcinoma: contributions of immunohistochemistry] [Article in Italian] Ferrari P, Trentini GP, De Gaetani C, Caragnani L, Righi E, Ferrari G. Dipartimento di Scienze Morfologiche e Medico-Legali dell'Universita di Modena. Despite the insights genetics and molecular biology have given to a better understanding of the mechanisms which lead to the onset and development of bladder carcinoma, the factors that influence its unpredictable and, at times, particularly aggressive outcome are still largely unknown. Also in bladder carcinoma the study of cellular differentiation markers has been replaced by that of genotypic alterations, and, mainly with the help of immunohistochemistry, of the expression of genes involved in cell proliferation and death, such as MTS1, TP53, Rb, c-myc, Bcl-2, c-erb-B2. So far, anyway, no independent and reliable indicator able to predict the outcome of the single tumour has been identified, and this issue seems to be best addressed by studies of the altered expression of more than one oncoprotein simultaneously. Fairly identical is the question arised by TP53 mutations, which, while worsening the evolution of advanced muscle-infiltrating tumours, hold a still unclear and debated meaning in superficial tumours. It is anyway clear that molecular analysis only may enable to reliably detect the presence of any TP53 mutations. As a matter of fact, the multiplicity of genetic mutations, the frequent transcript variations and the intrinsic limits of immunohistochemistry may explain the discrepancy between immunohistochemical and molecular analysis results, with specificity and sensitivity levels clinically not acceptable. To date, anyway, the biological and clinical meaning of this discrepancy has still to be clarified, as well as the clinical meaning, if any, of p53 overexpression in the absence of gene mutations. PMID: 9417298 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 708: J Exp Med. 1997 Dec 1;186(11):1873-84. C-myc-induced apoptosis in polycystic kidney disease is Bcl-2 and p53 independent. Trudel M, Lanoix J, Barisoni L, Blouin MJ, Desforges M, L'Italien C, D'Agati V. Institut de Recherches Cliniques de Montreal, Faculte de Medecine de l'Universite de Montreal, Montreal, Quebec, Canada H2W 1R7. The SBM mouse is a unique transgenic model of polycystic kidney disease (PKD) induced by the dysregulated expression of c-myc in renal tissue. In situ hybridization analysis demonstrated intense signal for the c-myc transgene overlying tubular cystic epithelium in SBM mice. Renal proliferation index in SBM kidneys was 10-fold increased over nontransgenic controls correlating with the presence of epithelial hyperplasia. The specificity of c-myc for the proliferative potential of epithelial cells was demonstrated by substitution of c-myc with the proto-oncogene c-fos or the transforming growth factor (TGF)-alpha within the same construct. No renal abnormalities were detected in 13 transgenic lines established, indicating that the PKD phenotype is dependent on functions specific to c-myc. We also investigated another well characterized function of c-myc, the regulation of apoptosis through pathways involving p53 and members of the bcl-2 family, which induce and inhibit apoptosis, respectively. The SBM kidney tissues, which overexpress c-myc, displayed a markedly elevated (10-100-fold) apoptotic index. However, no significant difference in bcl-2, bax, or p53 expression was observed in SBM kidney compared with controls. Direct proof that the heightened renal cellular apoptosis in PKD is not occurring through p53 was obtained by successive matings between SBM and p53(-/-) mice. All SBM offspring, irrespective of their p53 genotype, developed PKD with increased renal epithelial apoptotic index. In addition, overexpression of both bcl-2 and c-myc in double transgenic mice (SBB+/SBM+) also produced a similar PKD phenotype with a high apoptotic rate, showing that c-myc can bypass bcl-2 in vivo. Thus, the in vivo c-myc apoptotic pathway in SBM mice occurs through a p53- and bcl-2-independent mechanism. We conclude that the pathogenesis of PKD is c-myc specific and involves a critical imbalance between the opposing processes of cell proliferation and apoptosis. PMID: 9382886 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 709: Science. 1997 Dec 5;278(5344):1812-5. Requirement of NF-kappaB activation to suppress p53-independent apoptosis induced by oncogenic Ras. Mayo MW, Wang CY, Cogswell PC, Rogers-Graham KS, Lowe SW, Der CJ, Baldwin AS Jr. Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA. The ras proto-oncogene is frequently mutated in human tumors and functions to chronically stimulate signal transduction cascades resulting in the synthesis or activation of specific transcription factors, including Ets, c-Myc, c-Jun, and nuclear factor kappa B (NF-kappaB). These Ras-responsive transcription factors are required for transformation, but the mechanisms by which these proteins facilitate oncogenesis have not been fully established. Oncogenic Ras was shown to initiate a p53-independent apoptotic response that was suppressed through the activation of NF-kappaB. These results provide an explanation for the requirement of NF-kappaB for Ras-mediated oncogenesis and provide evidence that Ras-transformed cells are susceptible to apoptosis even if they do not express the p53 tumor-suppressor gene product. PMID: 9388187 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 710: Anticancer Res. 1997 Sep-Oct;17(5A):3593-7. In vivo effects of cyclophosphamide on oncogene and suppressor gene expression in a "follow up" study. Ember I, Kiss I. Department of Preventive Medicine, University Medical School of Pecs, Hungary. Cyclophosphamide is a chemotherapeutical drug, with proved carcinogenic side effects. Our previous experiments showed its effect on the expression of certain oncogenes and tumor suppressor genes. In order to further explore the effects of cyclophosphamide at the gene level an in vivo mouse model was developed. We compared the effects of cyclophosphamide with that of cyclosporine, which is a non genotoxic human carcinogenic chemical. After different time periods of intraperitoneal cyclophosphamide or cyclosporine injection, RNA was isolated from whole organs of experimental animals, and expression of onco/suppressor genes was determined by slot blot hybridisation. In our model we have proved that gene expression changes caused by cyclophosphamide can be detected even six months after treatment without tumor development. Our results support the hypothesis that gene expression investigations could be useful biomarkers in monitoring the effects of environmental carcinogenic compounds. PMID: 9413208 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 711: Science. 1997 Nov 14;278(5341):1246-7. Comment on: Science. 1997 Nov 14;278(5341):1305-9. A Myc-induced apoptosis pathway surfaces. Green DR. Division of Cellular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA. dgreen5240@aol.com Publication Types: Comment PMID: 9411752 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 712: Biochim Biophys Acta. 1997 Nov 27;1359(2):143-52. Reduced glutathione prevents nitric oxide-induced apoptosis in vascular smooth muscle cells. Zhao Z, Francis CE, Welch G, Loscalzo J, Ravid K. Department of Biochemistry, Boston University School of Medicine, MA 02118, USA. The control of medial and neointimal growth, in which vascular smooth muscle (VSM) plays a central role, is most important to the development of hypertension and atherosclerosis, respectively. Growth of vascular smooth muscle cells is regulated by a number of factors, including the vasodilator nitric oxide (NO). In addition, NO modulates intracellular thiol redox states and the thiol redox state of the cell influences NO production. We, therefore, examined the nature of the effect of NO on growth of VSM cells and its modulation by cellular glutathione content. Here, we report that NO, either generated by NO donors or synthesized by iNOS in VSM cells, inhibited DNA synthesis and induced apoptosis in this cell type. NO-induced apoptosis was associated with a significant decrease in the intracellular concentration of reduced glutathione and with an increase in the level of the tumor suppressor gene p53 mRNA. Moreover, addition of glutathione monoethylester to the culture restored the level of reduced glutathione in VSM cells, and prevented the NO-induced increase in p53 expression and programmed cell death. Our findings suggest a role for reduced glutathione in protecting VSM cells exposed to NO from apoptosis. PMID: 9409811 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 713: Cytokines Mol Ther. 1995 Mar;1(1):29-38. Expression of c-fos correlates with IFN-alpha responsiveness in Philadelphia chromosome positive chronic myelogenous leukemia. Eibl B, Greiter E, Grunewald K, Gastl G, Weyrer K, Thaler J, Aulitzky W, Herrmann F, Rapp U, Huber C. Department of Internal Medicine, University Hospital Innsbruck, Austria. This study evaluates (i) constitutive levels of oncogene and p53 transcripts in chronic phase CML patients and (ii) their modulations subsequent to in vivo therapy with rIFN-alpha 2c. Peripheral blood mononuclear cells (pbmc) and bone marrow cells of 26 patients were examined for c-fos, c-myc, p53 and the hybrid bcr/abl mRNA levels. Results indicated that (i) constitutive c-fos transcript levels are significantly higher in patients subsequently responding to IFN-alpha therapy (p < 0.01) and positively correlated with the proportion of lymphocytes (r = 0.6895, p < 0.01) and negatively with the proportion of immature cells (r = -0.568, p < 0.01) contained in the pbmc preparations tested, (ii) constitutive mRNA levels of the hybrid bcr/abl, c-myc and p53 are positively correlated with each other, but failed to relate to disease parameters, and (iii) acute and chronic in vivo exposure to IFN-alpha is accompanied by upregulation of c-fos and downregulation of c-myc mRNA levels in responder patients. Publication Types: Clinical Trial Clinical Trial, Phase II PMID: 9384661 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 714: Mol Cell Biol. 1997 Dec;17(12):7306-16. Transformed cells require continuous activity of RNA polymerase II to resist oncogene-induced apoptosis. Koumenis C, Giaccia A. Department of Radiation Oncology, Stanford University School of Medicine, California 94305, USA. Studies have indicated that deregulated oncogene expression can result in either programmed cell death or proliferation, depending on the cellular microenvironment. However, little is known about whether oncogenic signals in themselves are able to activate a cellular apoptotic program. We have tested the hypothesis that oncogenic signals in the absence of gene expression are sufficient to induce cell death, which would indicate that constitutive expression of antiapoptotic genes is necessary for maintenance of the transformed state. Using two highly specific RNA polymerase (RNAP) II inhibitors, 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) and alpha-amanitin, which inhibit RNAP II function by two distinct mechanisms, we found that inhibition of gene expression substantially increased apoptosis in a time- and dose-dependent manner in p53+/+- and p53(-/-)-transformed mouse embryonic fibroblasts and in HeLa cells, demonstrating that this type of apoptosis does not require wild-type p53. Engineered expression of an alpha-amanitin resistance RNAP II gene rendered cells resistant to induction of apoptosis by alpha-amanitin without affecting their sensitivity to DRB, indicating that alpha-amanitin induces apoptosis solely by inhibiting RNAP II function and not by a nonspecific mechanism. DRB-induced apoptosis was independent of the cell cycle or ongoing DNA replication, since DRB induced similar levels of apoptosis in asynchronous cells and cells synchronized by collection at mitosis. Inhibition of RNAP II in untransformed cells like Rat-1 or human AG1522 fibroblasts resulted not in apoptosis but in growth arrest. In contrast, deregulated expression of c-Myc in Rat-1 cells dramatically increased their sensitivity to DRB, directly demonstrating that apoptosis following inhibition of RNAP II function is greatly enhanced by oncogenic expression. The requirement for RNAP II function to prevent oncogene-induced apoptosis implies the need for the constitutive expression of an antiapoptotic gene(s) to maintain the transformed state. The differential sensitivities of untransformed and transformed cells to induction of apoptosis by transcriptional inhibition, coupled with the finding that this type of apoptosis is independent of p53 status, suggest that inhibition of RNAP II may be exploited therapeutically for the design of successful antitumor agents. PMID: 9372962 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 715: Ann Oncol. 1997 Oct;8(10):987-94. Intraclonal molecular heterogeneity suggests a hierarchy of pathogenetic events in Burkitt's lymphoma. Gutierrez MI, Bhatia K, Cherney B, Capello D, Gaidano G, Magrath I. Pediatric Branch, National Cancer Institute, NIH, Bethesda, MD 20892-1928, USA. BACKGROUND: Burkitt's lymphoma is a B-cell neoplasm characterized by a chromosomal translocation involving the c-myc gene. BL may carry, besides the c-myc translocation, several other lesions including a) mutations in c-myc, b) mutations in bcl-6, c) mutations in p53 and d) EBV genomes. In this report we describe a unique study of the timing of these genetic lesions during the evolution and progression of Burkitt's lymphoma. MATERIALS AND METHODS: From each of two patients with Burkitt's lymphoma, we established three different cell lines from different sites or at different times in the clinical course of the disease (diagnosis and relapse). Chromosomal aberrations were analyzed by karyotyping and the presence of molecular lesions determined by Southern blot, PCR, SSCP and sequence analyses. RESULTS: In each patient all the clones carry identical c-myc translocations, identical bcl-6 status (wild type or mutant) and the same productive VDJ rearrangement. However, within each individual patient, we could demonstrate the presence of intraclonal variation with respect to EBV, p53 mutations and c-myc mutations. CONCLUSIONS: c-myc translocation and bcl-6 mutations appear to be early events, mutations in the coding region of c-myc occur early but are an ongoing event, while mutations in the p53 gene seem to occur later. Discrete clonal bands reflecting independent EBV infection were observed in the cell lines from one HIV-associated Burkitt's lymphoma, suggesting the possibility that EBV infection may occur as a late event, at least in some HIV associated lymphomas. PMID: 9402172 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 716: Br J Cancer. 1997;76(11):1448-54. Similarity of apoptosis induction by 2-chlorodeoxyadenosine and cisplatin in human mononuclear blood cells. Borner MM, Joncourt F, Hotz MA. Institute of Medical Oncology, University of Bern, Inselspital, Switzerland. The purine analogue 2-chlorodeoxyadenosine (CdA) is unique compared with traditional antimetabolite drugs, as it has shown equal activity in dividing and resting lymphocytes. Poly(ADP-ribose)polymerase (PARP) activation and consecutive NAD+ consumption have been associated with the induction of apoptosis in resting cells. The potential of CdA to induce the p53-dependent DNA damage response was assessed in resting and phytohaemagglutinine (PHA)-activated peripheral blood mononuclear cells (PBMCs) and compared with cisplatin (DDP), a cell cycle-dependent and DNA-damaging agent that is mainly used in the treatment of solid tumours. Both drugs induced transactivation of the p53 target genes waf1 and mdm2, NAD+ consumption and apoptotic death. The expression pattern of p53 and waf1 suggests a partly p53-independent induction of waf1. The expression of c-myc and PARP, which both have a dual role in proliferation and apoptosis, was selectively induced by CdA. Cell cycle stimulation increased the cytotoxic activity of both drugs. These data show that DDP is also a potent inducer of apoptosis in resting and proliferating peripheral blood mononuclear cells. Activation of the p53-dependent DNA damage response seems to be an important component of the toxic effect of CdA. PMID: 9400941 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 717: Int J Cancer. 1997 Dec 10;73(6):816-21. Heterogeneous p53 mutations in a Burkitt lymphoma from an AIDS patient with monoclonal c-myc and VDJ rearrangements. Campomenosi P, Fronza G, Ottaggio L, Roncella S, Inga A, Bogliolo M, Monti P, Assereto P, Moro F, Cutrona G, Bozzo S, Chiorazzi N, Abbondandolo A, Ferrarini M. CSTA-Mutagenesis Laboratory, National Institute for Cancer Research (IST), Genoa, Italy. This study investigates the timing of p53 mutations detected in the malignant cells of a Burkitt's lymphoma cell line (BRG-P) with respect to other maturation or transforming events. The BRG-P cell line, derived from an AIDS patient, was of special value since it displayed subclones that had undergone an isotype switch from IgM to IgA1 (BRG-M and BRG-A cells). BRG-M and BRG-A cells were characterized by the same monoclonal c-myc and VDJ rearrangements and by the expression of Ig receptors with specificity for a 45 kDa protein of human breast cells. Analysis of p53 mutations in the different BRG subclones showed that 1) BRG-M cells displayed 2 different p53 mutations in trans; since the original BL cells also showed the same mutations, this finding indicated that both occurred in vivo; 2) one of the p53 alleles of BRG-A cells was lost, while the other showed a mutation different from those seen in BRG-M cells; and 3) all 3 mutations observed in BRG-M or BRG-A cells resulted in the functional inactivation of the transcriptional activation function of p53. Together, our data demonstrate that p53 mutations were relatively late events during lymphomagenesis. Moreover, in view of the role of p53 in cell apoptosis, it is conceivable that BRG cells were subjected to a strong selective pressure that favored p53 inactivation. Such inactivation was possibly required to counterbalance other potentially apoptotic events, including the presence of a deregulated c-myc oncogene and signals delivered by the host environment in situ. PMID: 9399658 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 718: Arch Ital Urol Androl. 1997 Sep;69(4):265-9. Molecular genetics of renal cell carcinoma. Vignoli GC, Martorana G. Clinica Urologica, Universita di Bologna. Significant research progress over the last few years has identified several major genetics contributors to RCC. A new classification of RCC validated by cytogenetic and molecular studies has been proposed including nonpapillary, papillary, chromophobe and oncocytic tumors. The cytogenetic analysis of patients with familial RCC, VHL disease and sporadic RCC have shown that WHL gene located on chromosome 3P 25 is a tumor suppressor gene. Other genes may be involved in the development of RCC, however with a less important incidence than VHL gene. Mutations of Rb and P53 genes can be associated with metastatic disease, mutations of the ras gene is rare whereas elevated level of myc oncogene are frequent but of little prognostic value. Controversial the role of ploidy and proliferation markers as independent prognostic factors. PMID: 9396188 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 719: Am J Hematol. 1997 Dec;56(4):206-13. Detection of BCL-6 rearrangements and p53 mutations in Malt-lymphomas. Gaidano G, Volpe G, Pastore C, Chiarle R, Capello D, Gloghini A, Perissinotto E, Savinelli F, Bosco M, Mazza U, Pileri S, Palestro G, Carbone A, Saglio G. Dipartimento di Scienze Mediche, Universita di Torino, Novara, Italy. gaidano@med.no.unipmn.it Twenty-seven lymphomas of mucosa-associated lymphoid tissue (MALT) derived from distinct anatomical sites were tested for the presence of genetic lesions commonly involved in B-cell lymphomagenesis, including activation of proto-oncogenes (BCL-1, BCL-2, BCL-6, and c-MYC), disruption of tumor suppressor loci (p53, 6q), and infection by viruses [Epstein-Barr virus (EBV), and Kaposi's sarcoma-herpesvirus/human herpesvirus-8 (KSHV/HHV-8)]. Sixteen low-grade and 11 high-grade MALT-lymphomas were included in the study. The presence of genetic lesions was tested by a combination of molecular approaches, including Southern blot hybridization, polymerase chain reaction (PCR), and PCR-single strand conformation polymorphism followed by DNA direct sequencing. Alterations of BCL-1, BCL-2, or c-MYC, as well as infection by KSHV/HHV-8, scored negative in all MALT-lymphomas analysed. Conversely, rearrangements of BCL-6 and mutations of p53 clustered with a fraction of high-grade MALT-lymphomas. Deletions of 6q occurred in selected cases of both low- and high-grade MALT-lymphomas, whereas a monoclonal infection by EBV was restricted to one single patient. These data corroborate the notion that the molecular pathogenesis of MALT-lymphomas differs substantially from that of nodal B-cell lymphomas. Occasionally, however, a proportion of high-grade MALT-lymphomas may harbor selected genetic lesions among the ones commonly involved in nodal B-cell lymphomagenesis. PMID: 9395180 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 720: Zhongguo Zhong Xi Yi Jie He Za Zhi. 1996 Aug;16(8):486-8. [Experimental study on inhibitory effect of yifei kangliu decoction on cell proliferation in lung cancer] [Article in Chinese] Xu L, Liu JX. Department of Traditional Chinese Medicine, Changzheng Hospital, Shanghai. In this study, the inhibitory effect of Yifei Kangliu Yin (YFKL) was observed on growth of LAX-83 human lung adenocarcinoma in naked mice. It was found that the YFKL could suppress the tumor growth significantly with a suppression rate of 45.59%. It was also found that positive expression of Ki-67 and cell proliferation significantly decreased, c-myc changed from positive to weak positive and P53 from positive to negative in the YFKL treated group. It suggested that the inhibitory effect of YFKL on proliferation of cancer cells might be realized by way of changing the oncogenetic expression of cancer, so as to influence the cell proliferation directly. PMID: 9387751 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 721: Int J Radiat Biol. 1997 Nov;72(5):547-59. Influence of ionizing radiation on proliferation, c-myc expression and the induction of apoptotic cell death in two breast tumour cell lines differing in p53 status. Watson NC, Di YM, Orr MS, Fornari FA Jr, Randolph JK, Magnet KJ, Jain PT, Gewirtz DA. Department of Medicine and Pharmacology/Toxicology, Virginia Commonwealth University, Medical College of Virginia, Richmond 23298, USA. PURPOSE: To determine the capacity of ionizing radiation to inhibit proliferation, to suppress c-myc expression and to induce apoptotic cell death in the p53 wild-type MCF-7 cell line and the p53 mutated MDA-MB231 cell line. MATERIALS AND METHODS: Growth inhibition and cell killing were determined by cell number and trypan blue exclusion. Apoptosis was assessed through cell morphology and fluorescent end-labelling. c-myc expression was monitored by Northern blotting. RESULTS: Inhibition of cell proliferation by ionizing radiation was similar in both cell lines. MDA-MB231 cells accumulated in G2 while MCF-7 cells accumulated in both the G1 and G2 phases of the cell cycle after irradiation. There was no evidence of apoptosis in either cell line. In MCF-7 cells, growth inhibition correlated closely with an early dose-dependent suppression of c-myc expression; in MDA-MB231 cells, there was no correspondence between growth inhibition and a transient, dose-independent reduction in c-myc message. CONCLUSIONS: These findings suggest that in the absence of classical apoptotic cell death, radiosensitivity is not predictably related to the p53 status of the cell. While both p53 and c-myc may be linked to the DNA damage response pathway, neither p53 nor c-myc are essential for growth arrest in response to ionizing radiation. PMID: 9374435 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 722: Br Med Bull. 1997;53(3):554-69. Apoptosis and carcinogenesis. Lyons SK, Clarke AR. Department of Pathology, University of Edinburgh, UK. Many tumours are characterised by increased levels of apoptosis. This observation establishes significance for this process in tumour development, but it does little to elucidate the nature of this role, nor does it yield information relevant to the early stages of carcinogenesis. To gain a better understanding of the importance of apoptosis, it has been necessary to create a number of transgenic model systems wherein the apoptotic response has been modified. Using this strategy, a number of genetic lesions have been identified which affect both the apoptotic pathway and predisposition to malignancy. These lesions can operate either directly, by blocking the induction of apoptosis; or indirectly, by increasing the selective pressure for further genetic change. The consequent deregulation of growth control and increase in mutation burden represent two key steps in carcinogenesis, underlining the pivotal role played in tumour suppression by the normal induction of apoptosis. Publication Types: Review PMID: 9374037 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 723: Gan To Kagaku Ryoho. 1997 Oct;24 Suppl 3:345-52. [Genetic alteration of lung cancer as a prognostic marker and its therapeutic implications] [Article in Japanese] Mitsudomi T, Takahashi T. Dept. of Thoracic Surgery, Aichi Cancer Center Hospital. Many genetic lesions found in non-small cell lung cancer (NSCLC) have been reported to be associated with a poor prognostic outcome of this disease. Such alterations include mutations of ras genes, overexpression of myc or erbB2 genes and inactivation of RB genes. Among them, the prognostic implications of the p53 gene have been most extensively studied; over 20 reports have been published. However, the significance of the p53 gene abnormality also still remains unclear. Therefore, we re-evaluated our 562 patients with NSCLC retrospectively to see if the p53 gene abnormality really had an effect on patients' survival in this large cohort. There was no effect of p53 gene abnormality on all patients with NSCLC or on those with squamous cell carcinoma, but p53 abnormality was a significant, independent prognostic marker in adenocarcinoma subset. We should plan a clinical trial of postoperative adjuvant therapy for patient with pulmonary adenocarcinoma incorporating information on the p53 gene status to possibly translate these findings into clinical practice. Publication Types: Review Review, Tutorial PMID: 9369906 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 724: FEBS Lett. 1997 Oct 13;416(1):113-6. Mechanisms of cycloheximide-induced apoptosis in liver cells. Alessenko AV, Boikov PYa, Filippova GN, Khrenov AV, Loginov AS, Makarieva ED. Institute of Biochemical Physics RAS, Moscow, Russia. aless@center.chph.ras.ru Cycloheximide in sublethal doses caused apoptosis in liver cells in vivo, inducing c-myc, c-fos, c-jun and p53 genes and accumulation of sphingosine, a toxic product of the sphingomyelin cycle. These data support the hypothesis that continuous synthesis of labile protective proteins is required to restrain apoptosis in liver; sphingosine might be important in mediating cycloheximide-induced apoptosis as an endogenous modulator of protein kinase C activity. PMID: 9369245 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 725: Biochim Biophys Acta. 1997 Oct 11;1358(3):314-20. Type of inducing signal regulates transactivation by p53. Borner MM, Joncourt F, Hotz MA. Institute of Medical Oncology, University of Bern, Inselspital, Switzerland. mborner@insel.unibe.ch The tumor suppressor gene p53 is expressed in the contrasting cell fates apoptosis and proliferation. We examined whether the transactivation of the p53 target genes, waf1 and mdm2, is dependent on the cause of p53 induction in human peripheral blood mononuclear cells (PBMC). Both apoptosis triggered by the purine analog 2-chlorodeoxyadenosine (CdA) and growth stimulation by the mitogen phytohemagglutinin (PHA) induced a comparable level and time course of p53 mRNA expression. Both stimuli led also to an increase of p53 protein levels. The cytotoxic agent, but not the mitogen, led to transactivation of waf1 and mdm2 within 18 h. Transactivation was followed by apoptosis of 89% of the PBMC within 48 h. The c-myc oncogene and poly(ADP-ribose)polymerase (PARP), which also have a dual function in proliferation and apoptosis, showed an early induction by both CdA and PHA. These results add further evidence that growth stimulation and DNA damage-induced apoptosis share early gene activation pathways in normal cells. However, since p53 does selectively translate into transactivation of target genes depending on the cause of induction, this function of p53 seems to be regulated by additional factors, which are closely related to the ultimate fate of the cell. PMID: 9366263 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 726: J Pathol. 1997 Aug;182(4):392-7. Apoptosis in colorectal carcinoma occurring in patients aged 45 years and under: relationship to prognosis, mitosis, and immunohistochemical demonstration of p53, c-myc and bcl-2 protein products. Langlois NE, Lamb J, Eremin O, Heys SD. Department of Pathology, University of Aberdeen, Medical School, Foresterhill, U.K. The aim of this study was to ascertain whether apoptotic counts have prognostic significance in colorectal cancer and if such counts are related to the expression of proteins implicated in cell cycle regulation. Material from a cohort of patients aged 45 years or less with colorectal carcinoma was re-examined to determine apoptotic and mitotic counts by light microscopy, in addition to assessing p53, c-myc, and bcl-2 protein status by immunohistochemistry. The apoptotic index in the 74 patients who were alive or who had died of colorectal carcinoma ranged from 1.2 per cent to 12.3 per cent and exhibited independent prognostic significance, with high counts predicting better survival (P = 0.02). Mitotic counts were not related to survival, despite a close correlation with apoptosis (r = 0.85). Tumours regarded as not staining with the CM1 antibody for p53 protein demonstrated higher apoptotic counts, compared with those that stained (medians 5.2 and 4.0 per cent, respectively; P = 0.03), but p53 expression was found not to be related to survival. The 68 tumours which stained for c-myc appeared to exhibit higher mitotic counts than those that did not. bcl-2 was detected in only four tumours. The latter two proteins exhibited no apparent relationship to the apoptotic index or survival. Although these results indicate a potential role for apoptotic counting in prognostic prediction in colorectal tumours, this is an uncommon group of patients who exhibited some atypical features. The likelihood of a proportion of cases arising within hereditary non-polyposis colorectal cancer syndrome may limit the application of the findings to a more general population with cancer of the colon and rectum. Further work is required, including critical measurement of reproducibility and assessment of the relative impact of this parameter compared with 'traditional' prognostic markers. PMID: 9306959 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 727: Oncogene. 1997 Sep 18;15(12):1395-406. Butyrate modulates DNA-damage-induced p53 response by induction of p53-independent differentiation and apoptosis. Janson W, Brandner G, Siegel J. Department of Virology, Institute of Medical Microbiology and Hygiene, Albert-Ludwig-University, Freiburg, Germany. Butyrate, a physiologically occurring agent, has been reported to decrease constitutively high expressed p53 levels in transformed cells. To elucidate whether butyrate also inhibits DNA-damage-induced p53 response we investigated the effects of butyrate and the anticancer drug mitomycin C in normal C3H10T1/2 cells harbouring wild-type p53. In comparison with p53-deficient fibroblasts we examined p53 protein level, cell cycle arrest, differentiation, and apoptosis. Butyrate induced G1 phase arrest, differentiation, and p53-independent increase in p21(waf1/cip1) protein. Moreover, butyrate induced p53-independent apoptosis, which was, as well as p53-mediated apoptosis, associated with a dose-dependent increase in Bax and c-Myc protein. Pretreatment with butyrate repressed dose-dependently mitomycin-C-induced p53 accumulation and interfered with p53-dependent cell cycle arrest. Butyrate further partially inhibited p53-mediated apoptosis, but low doses of butyrate were more effective than higher concentrations. This was reflected in an enhanced decrease in c-Myc and Bax protein in response to mitomycin C with low concentrations of butyrate. Our data indicate that the differentiation stimulus of butyrate, in association with p21(waf1/cip1) induction, and apoptosis, may explain antineoplastic effects of butyrate. Co-carcinogenic features of butyrate may result from inhibition of p53-mediated DNA damage response. PMID: 9333015 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 728: Leuk Lymphoma. 1997 Jul;26(3-4):369-76. Resistance to apoptosis induced by serum depletion and all-trans retinoic acid in drug-resistant leukemic cell lines. Kakihara T, Fukuda T, Kamishima T, Naito M, Tanaka A, Uchiyama M, Kishi K. Department of Pediatrics, Niigata University School of Medicine, Japan. The relation between resistance to anticancer drugs and resistance to apoptosis has been investigated in the human leukemic cell line(KY-821) and its drug-resistant sublines. Under serum depletion conditions, drug-resistant cell lines showed apoptotic resistance when compared with the parental cell line. Drug resistant cell lines also showed resistance to apoptosis when treated with all-trans retinoic acid. DNA fragmentation was low in drug resistant cell lines under both stimulations. Flowcytometry analysis did not show any alterations of the Fas antigen, p53, bcl-2 and c-myc protein expression toward inhibition of apoptotic response in drug-resistant sublines. These results indicate that drug-resistant leukemic cells still show resistance to apoptosis-inducing stimulation such as poor nutrition and differentiation-inducing agents. PMID: 9322900 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 729: Oncogene. 1997 Sep;15(11):1295-302. Genomic instability and apoptosis are frequent in p53 deficient young mice. Fukasawa K, Wiener F, Vande Woude GF, Mai S. ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Maryland 21702-1201, USA. The loss of p53 tumor suppressor functions results in genetic instability, characteristically associated with changes in chromosome ploidy and gene amplification. In vivo, we find that cells from various organs of 4 to 6-week old p53-nullizygous (p53-/-) mice display aneuploidy and frequent gene amplification as well as evidence for apoptosis. Regardless of tissue types, many p53-/- cells contain multiple centrosomes and abnormally formed mitotic spindles. Thus, chromosome instability in vivo may be associated with abnormal centrosome amplification. Moreover, we observed a significant increase in the number of cells overexpressing c-Myc in p53-/- mice. Consistent with previous studies showing that c-Myc overexpression is associated with gene amplification in vitro, many of the p53-/- cells exhibited, in the same cell, c-Myc overexpression and amplified c-myc, dihydrofolate reductase (DHFR), and carbamoyl-phosphate synthetase-aspartate transcarbamoyl-dihydroorotase (CAD) genes. Furthermore, apoptosis was frequently observed in cells isolated from p53-/- mice. The apoptotic cells contained abnormally amplified centrosomes, displayed aneuploidy, high levels of c-Myc expression, as well as gene amplification. These results indicate that a high number of aberrant cells is eliminated by p53-independent pathways in vivo. PMID: 9315097 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 730: Eur J Haematol. 1997 Sep;59(3):148-54. Cell proliferation, bcl-2, c-myc, p53 and apoptosis as indicators of different aggressiveness in small lymphocytic lymphoma (SLL). Palestro G, Ponti R, Chiusa L, Chiarle R, Geuna M, Novero D, Freilone R, Pich A. Department of Biomedical Sciences and Human Oncology, University of Torino Medical School, Italy. Cell proliferation activity, by MIB1 mAb, expression of bcl-2, c-myc and p53 gene proteins and apoptotic index (AI) were assessed in 54 cases of SLL and compared to the morphological subtypes of this disorder, defined by Lennert on the basis of amount and distribution of small and larger activated lymphocytes as diffuse, tumor-forming and pseudofollicular subtypes (DS, TFS, PFS). MIB1 scores showed significant differences between DS, PFS and TFS (5.5%, 16.61% and 24.14%, respectively; p < 0.0001). Worth noting, the MIB1 score did not differ significantly when comparing DS with the diffuse areas of PFS, or TFS with the pseudofollicles of PFS. The mean bcl-2 gene protein score was displayed to a high extent in all subtypes, but less extensively by larger activated lymphocytes that, conversely, expressed c-myc. MIB1 score correlated negatively with bcl-2 and positively with c-myc protein scores. These findings suggest that lymphocytes protected from apoptosis by bcl-2 would be exponed to cell activation and growth acceleration provided by c-myc. This condition would account for a different aggressiveness of morphologically activated subtypes, such as TFS and PFS with larger pseudofollicles. The survival analysis, performed in 23 cases, showed a trend of association of cell proliferation and c-myc expression with a more aggressive progression of the disease. Overexpression of p53 and apoptosis were found only in a minority of cases, unrelated to the subtypes. In conclusion, cell growth fraction, bcl-2 and c-myc assessment may be of help in predicting the aggressiveness of different subtypes of SLL. This approach should be most conveniently applied to PFS, which represents a continuum between DS and TFS, in order to distinguish, in this heterogeneous subtype, more indolent from more aggressive disorders. PMID: 9310122 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 731: Shock. 1997 Sep;8(3):186-92. Calcium blockade reduces renal apoptosis during ischemia reperfusion. Raafat AM, Murray MT, McGuire T, DeFrain M, Franko AP, Zafar RS, Palmer K, Diebel L, Dulchavsky SA. Department of Surgery, Wayne State University School of Medicine, Detroit, Michigan 48201, USA. Apoptosis is well described in invertebrates and recently documented in mammals. The prevalence and pathophysiology of mammalian apoptosis is unknown and may have clinical ramifications. The aim of this study is to investigate the apoptotic response during kidney ischemia-reperfusion (I/R) injury. Kidney I/R was initiated in anesthetized rats by occlusion of the renal pedicle for 45 min with or without pretreatment with .2 mg/kg verapamil: control animals received sham exposure. Flow was re-established after ischemia and the animals were allowed to recover for 24 h. Bilateral kidneys were harvested for DNA electrophoresis, Western analysis for p53, Northern analysis for c-myc expression, and light and electron microscopic analysis. Kidney I/R caused characteristic DNA laddering in the clamped kidney, and less extensive laddering was seen in the contralateral kidney. Light and electron microscopic analysis confirmed apoptotic morphology in the reperfused tissues. Verapamil pretreatment completely abolished DNA laddering and attenuated the microscopic evidence of apoptosis. p53 levels were increased by I/R in the ischemic kidney and moderately increased in the contralateral organ. c-myc mRNA levels were increased by the I/R insult. Kidney I/R injury may induce global apoptosis, which seems to be associated with an alteration in calcium homeostasis. The increase in p53 and c-myc mRNA levels seen with I/R may facilitate apoptosis. Calcium modulation seems to reduce apoptosis during I/R and may have therapeutic implications. PMID: 9377165 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 732: Radiat Oncol Investig. 1997;5(3):158-62. Oncogenic changes in murine lymphoid tumors induced by in utero exposure to ionizing radiation. Lumniczky K, Antal S, Unger E, Hidvegi EJ, Safrany G. Department of Molecular Radiobiology, National Research Institute for Radiobiology and Radiobygiene, Budapest, Hungary. We have investigated the oncogenic alterations in murine lymphomas induced by in utero exposure to gamma-radiation. The expression of the myc oncogene increased in 23% of the tumors. Alterations in the expression of the ras oncogenes and in the p53 tumor suppressor gene were not characteristic. The p53 gene was mutated in a low percentage of the tumors (12%). Ras mutations were not detected. Loss of heterozygosity (LOH) at the p53 locus was found in 30% of the tumors, and LOH at the mts tumor suppressor gene was detected in 23% of lymphomas. Multiple oncogenic changes were infrequent in the investigated tumors. There were no essential differences in the frequency of carcinogenic alterations in spontaneous and gamma-radiation-induced lymphomas. PMID: 9303076 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 733: Radiat Oncol Investig. 1997;5(3):150-3. Apoptosis and other effects of radiation in normal human urothelial cells. Mothersill C, O'Malley K, Murphy D, Seymour CB. Radiation Science Centre, Dublin Institute of Technology, Ireland. cmothersill@rsc.iol.ie In this paper, an attempt is made to identify endpoints that might be of potential use in the quantification of radiation effects in human tissues. Irradiated cultures of cells that are not selected for clonogenic survival but are left in situ to grow after irradiation show a wide variety of morphological and biochemical abnormalities. These include nuclear fragmentation and other evidence of programmed cell death, but they also include a considerable amount of lysis, necrosis, and persistent abnormal growth and function, which are expressed in the progeny of irradiated cells. Induction of proteins associated with stress or shock responses, growth and cell cycle control, and control of apoptosis are also seen and may persist. The dose dependence of these various responses is documented, because it probably determines to a large extent the outcome of radiation exposure in terms of whether a cell dies, divides normally, or develops genomic instability, mutation, and ultimate carcinogenic progression of the progeny. Clearly, a cell that dies presents no further threat to the organism, nor does a fully repaired cell. Therefore, a major challenge facing radiation protection research is to define the population at risk of surviving with damage. The results show that there is a variation in response to radiation between different patient cultures that is detectable in an explant culture system of primary normal human urothelium. The growth pattern and protein expression postirradiation is consistent with apoptosis being a major determinant of low dose response to radiation. This form of death appears to be suppressed at higher doses and, in the majority of subjects, results in the presence of a highly abnormal population of cells, even though the population size is the same whether their progenitors were irradiated or not. PMID: 9303074 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 734: Cell Growth Differ. 1997 Sep;8(9):951-61. p53-independent induction of p21WAF1/CIP1 expression in pericentral hepatocytes following carbon tetrachloride intoxication. Serfas MS, Goufman E, Feuerman MH, Gartel AL, Tyner AL. Department of Genetics, University of Illinois at Chicago 60607, USA. The cyclin-dependent kinase, proliferating cell nuclear antigen, and stress-activated protein kinase/c-jun NH2 terminal kinase inhibitor p21WAF1/CIP1 can induce G1 arrest, and its expression coincides with the cessation of replication in many systems. We examined expression of p21 during the early stages of carbon tetrachloride intoxication in the mouse liver and observed a dramatic increase in p21 RNA levels between 4 and 8 h after administration. p21 expression, visualized by in situ hybridization, is induced in pericentral hepatocytes before carbon tetrachloride-induced necrosis. Examination of c-fos and c-myc expression patterns confirm that these immediate-early genes are induced in similar regions of the mouse liver. p21 induction is not dependent on p53; we observed similar levels and localization of p21 in wild-type and p53 null animals. Immunohistochemical localization of p21 and CCAAT/enhancer-binding protein expression shows that p21 protein accumulation is limited to a subset of CCAAT/enhancer-binding protein-positive hepatocytes. A second peak of periportal and intermediate zone-specific p21 gene expression, appearing 1-2 days after injection, is also p53 independent and may represent cell cycle checkpoints or postmitotic growth arrest. Sporadic p21 expression was also detected in pairs of hepatocytes distributed throughout the liver acini in healthy animals. Together, these data suggest several roles for p21 in the liver in response to toxicity, regeneration, and growth inhibition. PMID: 9300178 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 735: Cytometry. 1997 Sep 1;29(1):1-27. Common patterns of genetic evolution in human solid tumors. Shackney SE, Shankey TV. Allegheny University of the Health Sciences, Department of Human Oncology, Allegheny Campus, Pittsburgh, Pennsylvania 15212, USA. shackney@pgh.AUHS.edu Human solid tumors develop multiple genetic evolutionary abnormalities as they evolve. Studies that have focused primarily on early colorectal cancer have suggested that genetic instability is a prominent feature of preinvasive disease. At least two separate mechanisms for the generation of genetic instability have been identified. The first, which involves widespread microsatellite instability in near-diploid cells, affects less than one-fifth of colon cancers. The second form of genetic instability is characterized by the development of p53 gene abnormalities that result in gross aneuploidy and multiple structural chromosomal changes. p53/aneuploidy affects most colon cancers, breast cancers, and many other solid tumors. This genetic evolutionary change commonly occurs at the interface between severe dysplasia and invasive disease. Specific post-aneuploid sequences of genetic changes that are relevant to tumor progression often involve the accumulation of multiple gain-of-function abnormalities in individual cells. The co-occurrence of Her-2/neu overexpression and EGF receptor overexpression in the same aneuploid cells defines an adeno/squamous genetic evolutionary sequence that is common to ductal breast cancers, non-small cell lung cancers, and other solid tumors. Later steps in this sequence include ras and c-myc overexpression. The neuroendocrine genetic evolutionary sequence is a separate branch of the p53/aneuploidy sequence with distinctive features that include loss of Rb and raf1 overexpression. Her-2/neu overexpression is not characteristic of this sequence; c-myc amplification/overexpression is common to both p53-associated sequences. The neuroendocrine sequence is found in small cell carcinoma of the lung and in minor proportions of other solid tumors, including breast cancer. Multiparameter cell-based methods are especially well suited for elucidation in human solid tumors of the genetic evolutionary sequences that could provide a rational scientific basis for determining prognosis and for optimizing therapy in individual cancer patients. Publication Types: Review PMID: 9298807 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 736: Exp Hematol. 1997 Sep;25(10):1042-50. Differential regulation by hematopoietic growth factors of apoptosis and mitosis in acute myeloblastic leukemia cells. Murohashi I, Yoshida K, Handa A, Murayoshi M, Yoshida S, Jinnai I, Bessho M, Hirashima K. First Department of Internal Medicine, Saitama Medical School, Japan. We evaluated the effects of various hematopoietic growth factors (HGFs) on the prevention of apoptosis in blasts from 19 patients with acute myeloblastic leukemia (AML) by assessing DNA ladder formation. After incubation without HGF, apoptosis was noted in all but two patients. HGFs prevented, did not affect, or enhanced apoptosis in 39 (60%), 14 (22%), or 12 (18%) of 65 suspension cultures, respectively. HGFs that prevented apoptosis also stimulated and/or synergized blast colony formation in 35 of 39 corresponding methylcellulose cultures. HGFs that alone stimulated colony formation also prevented apoptosis in all but two of 28 corresponding suspension cultures. In contrast, HGFs that did not prevent apoptosis also failed to stimulate growth in 17 of 26 corresponding methylcellulose cultures. HGFs that enhanced apoptosis alone never stimulated colony formation. After incubation, we noted enhanced c-fos and cjun genes as well as induction of p21 protein. An appropriate dose of HGF elevated c-fos, reduced c-jun and p21, induced G1/S transition, and inhibited apoptosis. In two patients, apoptosis was not induced after incubation. Cells not treated with HGF expressed no c-fos, c-jun, or c-myc, and remained in G0/G1. Taken together, our results support the conclusion that not only c-fos, cjun, and c-myc, but also p53 and p21 are required for blast apoptosis. HGF differentially prevents apoptosis and induces mitosis, and both events seem to be integral to the self-renewal of AML clonogenic cells. PMID: 9293901 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 737: Virchows Arch. 1997 Aug;431(2):111-7. Proliferation and apoptosis in proliferative lesions of the colon and rectum. Kikuchi Y, Dinjens WN, Bosman FT. Institute of Pathology, Erasmus University, Rotterdam, The Netherlands. Classically, neoplasia has been considered to be primarily a disturbance in the regulation of proliferation, but it is now clear that programmed cell death is dysregulated as well as proliferation. The genes that are implicated in the regulation of these processes, such as p53, c-myc and bcl-2, are often also altered in neoplasms. We have studied proliferation and programmed cell death in hyperplastic polyps, adenomas, carcinomas in adenomas and adenocarcinomas of the colorectum, using the MIB-1 antibody which recognizes the Ki-67 proliferation related antigen, and an in situ nick-end labelling procedure for histochemical labelling of proliferating and apoptotic cells. In addition, immunohistochemistry was used to study the expression of the p53, c-myc and bcl-2 proteins. The material studied consisted of 12 samples of normal mucosa, 8 hyperplastic polyps, 39 adenomas with different degrees of dysplasia and including 3 that carried a carcinoma, and 10 adenocarcinomas, all formalin fixed and paraffin embedded. The Ki-67 index indicated that proliferation increased progressively in hyperplasia, through different degrees of dysplasia in adenoma, to reach the highest level (Ki-67 index of 50%) in adenocarcinoma. Apoptosis also increased in hyperplastic polyps and in adenomas, but decreased significantly in adenocarcinomas. p53 Labelling was seen in 77% of the carcinomas but in only 3% of the adenomas. Expression of c-myc increased in adenomas and carcinomas. Furthermore, a shift from predominantly nuclear to predominantly cytoplasmic expression was seen in progressive neoplasms. Expression of bcl-2 was increased in an occasional hyperplastic polyp, but was increased markedly in almost all adenomas. Strikingly, in the adenomas with a carcinoma, the carcinoma showed weaker bcl-2 expression than the adenoma. In 20% of the carcinomas some bcl-2 staining was seen but this was less extensive than in the adenomas. Our findings indicate that in the progression from adenoma to carcinoma both increased proliferation and decreased apoptosis occur. This is paralleled by an increased expression of p53 and an increased and predominantly cytoplasmic expression of c-myc, but a decreased expression of bcl-2. This decreased bcl-2 expression does not lead to an increase in apoptotic activity. PMID: 9293892 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 738: Oncology. 1997 Sep-Oct;54(5):429-37. Comparison of cytogenetics, cytokine secretion, and oncogene expression in primary cultures of renal carcinoma cells. Lahn M, Kunzmann R, Kohler G, Ikle DN, Hentrich I, Jesuiter H, Kulmburg P, Veelken H, Mackensen A, Rosenthal F, Lindemann A. Abteilung Innere Medizin I, Hamatologie-Onkologie, Klinikum der Albert-Ludwigs-Universitat Freiburg, Germany. MichaLahn@aol.com We compared the cytogenetic pattern of 20 different primary tumor cell cultures (PTCC) of renal cell carcinoma (RCC) to their cytokine secretion and oncogene expression. High secretion of IL-6 (gene locus on chromosome 7p21-p14) was correlated with the gain of an additional chromosome 7. Structural changes involving chromosome 5q22, the site of the GM-CSF gene, were matched with the high secretion of GM-CSF in PTCC. No such association was found for beta 2-microglobulin, TGF-beta 1, TNF-alpha, IL-8, and oncogenes, such as c-fos, c-myc, and pan-ras. Our approach may be useful in simultaneously analyzing several factors contributing to tumor progression and may contribute to understanding the multistep development of RCC. PMID: 9260606 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 739: J Cell Biochem. 1997 Sep 1;66(3):309-21. Expression of cellular genes in HPV16-immortalized and cigarette smoke condensate-transformed human endocervical cells. Yang X, Nakao Y, Pater MM, Tang SC, Pater A. Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Canada. We studied the molecular mechanism of successive multistep cervical carcinogenic progression with our previously established in vitro model system. This system was composed of primary human endocervical cells (HEN), two lines of HEN immortalized by HPV16 and their counterparts subsequently malignantly transformed by cigarette smoke condensate (CSC). The expression was examined of diverse cellular genes associated with oncogenesis and senescence, especially for cervical cancer. Consistent results were seen for the pairs of immortalized and malignantly transformed lines. Immortalization of HEN by HPV16 resulted in enhanced expression of H-ras, c-myc, B-myb, p53, p16INK4 and PCNA mRNA; enhanced expression of p16 and PCNA proteins; decreased expression of WAF1/p21/Cip1/Sid1 and fibronectin mRNA; and decreased p53 protein. On the other hand, the CSC-transformed counterparts of HPV16-immortalized cells had up-regulated levels of B-myb, p53 and WAF1 mRNA and p53 protein. Our results indicate that the differential activation or inactivation of multiple cellular genes is important for the immortalization, as well as the transformation, of human cervical cells. Further, we suggest that our in vitro model system is useful for investigating the molecular mechanism of multistep cervical carcinogenesis. PMID: 9257188 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 740: Med Pediatr Oncol. 1997 Sep;29(3):206-7. Concomitant p53 mutation and MYCN amplification in neuroblastoma. Manhani R, Cristofani LM, Odone Filho V, Bendit I. Research and Molecular Biology Division, Pro-Sangue Hemocentro de Sao Paulo Foundation, Brazil. The MYCN oncogene is amplified in 20% of childhood neuroblastoma and is associated independently with poor prognosis. Alteration of the p53 tumor supressor gene, in contrast, occurs infrequently in these tumors. In this report, we described a 3-year-old girl with stage IV neuroblastoma. Molecular analysis revealed, both MYCN gene amplification and a point mutation of the p53 tumor supressor gene. To our knowledge, this is the first reported case of neuroblastoma with genetic alterations of both these genes. Publication Types: Case Reports PMID: 9212845 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 741: J Cell Biol. 1997 Aug 25;138(4):901-11. Loss of matrix adhesion triggers rapid transformation-selective apoptosis in fibroblasts. McGill G, Shimamura A, Bates RC, Savage RE, Fisher DE. Division of Pediatric Hematology/Oncology, Dana Farber Cancer Institute, Children's Hospital, Boston, Massachusetts 02115, USA. Cell-matrix and cell-cell adhesion are recognized physiological determinants of cell growth and survival. In epithelial and endothelial cell systems, oncogenic transformation has in several cases been shown to confer resistance to apoptosis upon depriving cells of substrate adhesion. We examined the effects of oncogenic transformation in adherent versus adhesion- deprived primary embryonic fibroblasts. Whereas untransformed early passage fibroblasts undergo cell cycle arrest, their Myc/Ras- or E1A/Ras-transformed counterparts rapidly enter apoptosis when placed into suspension. This phenomenon also occurs upon incubation with a soluble, RGD-containing integrin ligand and is blocked by a peptide antagonist to ICE family proteases or by aggregation of cells plated at high density. Loss of wild-type p53 modulates the kinetics but does not abrogate this death pathway. Transformation with activated Src rather than Ras rendered fibroblasts selectively resistant to adhesion-dependent apoptosis, an effect likely related to Src's role in integrin signaling, while simultaneously sensitizing the cells to radiation-induced apoptosis. Thus cell adhesion events regulate transformation-selective apoptosis in fibroblasts and provide potentially important targets for understanding and interfering with tumor cell viability. PMID: 9265655 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 742: Int J Cancer. 1997 Aug 7;72(4):599-603. Loss of heterozygosity at the TP53 gene: independent occurrence from genetic instability events in node-negative breast cancer. Lizard-Nacol S, Riedinger JM, Lizard G, Glasser AL, Coudray N, Chaplain G, Guerrin J. Laboratory of Molecular Genetics, Centre G.F. Leclerc, Dijon, France. TP53 abnormalities have been reported as an early event in the process of cellular transformation of human breast cancers, and involved in mammary-tumor evolution, from in situ to invasive disease. In this study, node-negative (N-) tumors were examined for TP53 allelic loss in relation to different genetic instability events, including allelic loss at chromosome 17p13.3 and c-H-ras-1 loci, as well as alteration of the c-myc and c-erbB-2/neu oncogenes. TP53 allelic loss was analyzed to determine whether such an abnormality was the more important, among other genetic events, in the N- tumors, whether it appeared independently of these genetic events, and whether accumulation of genetic events arises in this group of breast tumors. Clinicopathological parameters were also examined. Loss of heterozygosity (LOH) at the TP53 gene appears the most frequent alteration detected (26% vs. 13%, 8%, 9% and 3% for LOH at D17S30 and c-H-ras-1 loci, and amplification of c-myc and c-erbB-2/neu respectively). There was no association between LOH at the TP53 locus and other genetic events. Among clinicopathological parameters, significant associations were observed only with estrogen-receptor-negative tumors (p = 0.05). Our results demonstrate that LOH at TP53 arises more frequently in the N- breast cancer, thus supporting earlier findings suggesting that TP53 abnormality has a role early in the pathogenesis of breast lesions. Moreover, the data indicate that accumulation of many genetic events occurs at a low level in N- breast tumors, and that TP53 abnormality occurs independently of these genetic events. PMID: 9259397 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 743: Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):8162-7. The hepatitis B virus X gene induces p53-mediated programmed cell death. Chirillo P, Pagano S, Natoli G, Puri PL, Burgio VL, Balsano C, Levrero M. Fondazione Andrea Cesalpino, Policlinico Umberto I, Universita degli Studi di Roma La Sapienza, 00161 Rome, Italy. The human hepatitis B virus (HBV) protein pX is a multifunctional regulatory protein that is known to affect both transcription and cell growth. Here we describe induction of apoptosis in NIH 3T3 polyclonal cell lines upon stimulation of pX expression from a dexamethasone inducible mouse mammary tumor virus (MMTV)-X expression vector. The effect of long-term pX expression on the cell survival of mouse fibroblasts was confirmed in colony generation assays. This effect is not shared either by the other HBV products and it is c-myc mediated, as shown by the use of a dominant negative deletion mutant of c-myc. pX also sensitize cells to programmed cell death after exposure to DNA damaging agents. Taking advantage of stable transfectants carrying the p53val135 temperature-sensitive allele, we directly demonstrate that induction of apoptosis by pX requires p53. In p53 null mouse embryo fibroblasts pX activates transcription and confers an evident growth advantage without loss of cell viability. Although pX protein was not detectable in the experimental conditions we used, our results indicate that its expression affects both cell growth and cell death control. PMID: 9223332 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 744: Biochem Biophys Res Commun. 1997 Jul 18;236(2):396-401. Growth inhibition and induction of apoptosis by HGF in transformed rat liver epithelial cells. Conner EA, Wirth PJ, Kiss A, Santoni-Rugiu E, Thorgeirsson SS. Division of Basic Sciences, National Cancer Institute, Bethesda, Maryland 20892-4255, USA. Recently we demonstrated in a transgenic mouse model that hepatocyte growth factor (HGF) inhibits c-myc dependent hepatocarcinogenesis. The inhibitory effects of HGF in carcinogenesis were further characterized using a series of rat liver epithelial (RLE) cell lines which were transformed in vitro with either aflatoxin or oncogenes, or spontaneously. HGF caused a cytostatic effect and enhanced cell motility in spontaneously and aflatoxin-transformed cells. In normal RLE cells HGF was slightly stimulatory and did not induce scattering. The HGF receptor was tyrosine phosphorylated in all cell lines, indicating that it is functionally active and capable of signaling events. In the aflatoxin transformed cells HGF also induced apoptosis, associated with constitutive c-myc expression and 1 Kb bax-alpha transcripts. These findings indicate that transformed RLE cell lines may provide a useful model to further examine the mechanism(s) by which HGF and its receptor modulate neoplastic development. PMID: 9240448 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 745: Cancer Res. 1997 Jul 15;57(14):3016-25. Human ornithine decarboxylase-overproducing NIH3T3 cells induce rapidly growing, highly vascularized tumors in nude mice. Auvinen M, Laine A, Paasinen-Sohns A, Kangas A, Kangas L, Saksela O, Andersson LC, Holtta E. Department of Pathology, University of Helsinki, Finland. Overexpression of human ornithine decarboxylase (ODC) under the control of strong promoters induces morphological transformation of immortalized NIH3T3 and Rat-1 fibroblasts [M. Auvinen et al., Nature (Lond.), 360: 355-358, 1992]. We demonstrate here that ODC-overproducing NIH3T3 cells are tumorigenic in nude mice, giving rise to rapidly growing, large fibrosarcomas at the site of inoculation. The tumors are capable of invading host fat and muscle tissues and are vascularized abundantly. To disclose the molecular mechanism(s) driving the tumorigenic, invasive, and angiogenic phenotype of the tumors, the ODC-overproducing cell lines and tumor tissues were analyzed for the expression of various potential regulators and mediators of cell proliferation, matrix degradation, and angiogenesis. The tumorigenicity of ODC transformants was associated with elevated polyamine levels and down-regulated growth factor receptors. The invasiveness of the ODC-induced tumors could not be attributed to overexpression of various known extracellular matrix-degrading proteases or matrix metalloproteinases. The induction of the tumor neovascularization proved not to be elicited by vascular endothelial growth factor or basic fibroblast growth factor. Instead, the ODC-overexpressing cells appeared to secrete a novel angiogenic factor(s) that was able to promote migration of bovine capillary endothelial cells in collagen gels and increase the proliferation of human endothelial cells in vitro. In parallel, ODC-transformed cells displayed down-regulation of thrombospondin-1 and -2, the negative regulators of angiogenesis. Thus, the induction of the angiogenic phenotype of the ODC transformants is likely due both to increased expression and secretion of the new angiogenesis-stimulating factor(s) and decreased production and release of the antiangiogenic thrombospondins. PMID: 9230217 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 746: Cancer Res. 1997 Jul 15;57(14):2896-903. Phenobarbital causes apoptosis in conditionally immortalized mouse hepatocytes depending on deregulated c-myc expression: characterization of an unexpected effect. Osanai M, Ogawa K, Lee GH. Department of Pathology, Asahikawa Medical College, Nishikagura, Japan. The CHST8 mouse hepatocyte cell line, conditionally immortalized with the temperature-sensitive SV40 large T antigen gene, rapidly proliferates at 33 degrees C with active expression of the c-myc proto-oncogene but, due to the heat-labile nature of the mutant T antigens, becomes growth arrested and morphologically senescent at 39 degrees C; this is accompanied by the disappearance of c-myc transcripts. In a previous study, we transfected the CHST8 cells at 33 degrees C with an activated c-H-ras or a c-myc, both of which are frequently involved in mouse hepatocarcinogenesis in vivo. When the temperature was shifted to 39 degrees C, cells with only one of the exogenous oncogenes did not escape from the senescence, but those containing both exhibited an immortal phenotype. In the present study, using this in vitro model of hepatocarcinogenesis, we demonstrated that phenobarbital, a tumor promoter of rodent hepatocarcinogenesis, triggers remarkable apoptosis specifically in the c-myc-transfected CHST8 cells at 39 degrees C, which show abundant c-myc expression despite growth arrest. Dissociation of p53 proteins from degrading T antigens followed by a phenobarbital and c-myc-dependent, 15-fold induction of Bax protein, known to activate the apoptotic pathway downstream of p53, occurred in association with this phenomenon. The effects of phenobarbital and c-myc in increasing Bax on shifting the temperature from 33 degrees C to 39 degrees C were additive, with both having similar degrees of influence on the protein level. Interestingly, subsequent introduction of an activated c-H-ras oncogene into the c-myc-transfected CHST8 cells resulted not only in escape from the growth arrest at 39 degrees C but also in complete inhibition of the phenobarbital-inducible apoptosis along with de novo induction of the Bax antagonist, Bcl-2. These findings strongly suggest that the phenobarbital-inducible apoptosis is mediated by Bax. Although it is a common notion that phenobarbital promotes liver tumor development through suppression of apoptosis, our results, together with the known fact that phenobarbital occasionally inhibits hepatocarcinogenesis in mice, indicate a problematic complexity in its biological activities. PMID: 9230198 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 747: Int J Radiat Biol. 1997 Jul;72(1):21-31. Induction of multiple PCR-SSCPE mobility shifts in p53 exons in cultures of normal human urothelium exposed to low-dose gamma-radiation. Colucci S, Mothersill C, Harney J, Gamble SC, Seymour C, Arrand JE. Radiation Science Centre, Dublin Institute of Technology, Ireland. We have previously shown that primary explant cultures of human urothelium exposed to low doses of gamma-radiation subsequently accumulate a high level of stable p53 but it was not clear from those studies whether this protein stabilization occurred through an event in another gene involved in p53 protein control or possibly an epigenetic event. In these experiments, primary urothelial cultures from five different patients were exposed to either 0.5 or 5 Gy gamma-radiation from a 60 Cobalt source and allowed to grow for 7-10 division cycles to allow development of any radiation-induced, non-lethal changes in the cells. C-myc, Bcl-2 and stable p53 proteins were found to be elevated in cultures following both radiation doses. PCR-SSCPE analysis of the p53 gene was performed on cultures in order to determine whether genetic mutations could be the underlying basis for persistent increased stable p53 expression. Following 0.5 Gy exposure, the cultures also developed multiple distinct 'foci' of rapidly dividing cells which strongly overexpressed p53. These grew on a background of morphologically normal cells. When such foci were selectively analysed for their p53 mutation status by PCR-SSCPE, there was evidence that they contained cells which had developed changes to the p53 gene post-irradiation. These changes appeared to occur more frequently in focal cells than in cells of normal morphological appearance in the same culture. These results may have mechanistic importance given the controversy regarding low-dose radiation effects and p53-related genomic instability. PMID: 9246191 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 748: Dis Colon Rectum. 1997 Jul;40(7):785-90. Coexpression of Bcl-2, c-Myc, and p53 oncoproteins as prognostic discriminants in patients with colorectal carcinoma. Bhatavdekar JM, Patel DD, Ghosh N, Chikhlikar PR, Trivedi TI, Suthar TP, Doctor SS, Shah NG, Balar DB. The Gujarat Cancer Society, Asarwa, Ahmedabad, India. PURPOSE: This study was undertaken to evaluate the clinical use of Bcl-2, c-Myc, and p53 oncoproteins, either singly or in combination, as prognostic discriminants relative to recurrence and overall survival in patients with Dukes B or C colorectal carcinoma. METHODS: Analyses were made on archival pathology tissues of 48 patients with colorectal cancer. The oncoproteins were localized using commercially available monoclonal antibodies: clone 124 for Bcl-2, 9E11 for c-Myc, and DO-7 for p53. The avidin-biotin peroxidase complex method was used. Patients were followed up for a period of 2 to 36 months. RESULTS: Expression of Bcl-2 and c-Myc was cytoplasmic, whereas nuclear p53 immunoreactivity was localized in the tumor cells. Sixty percent (29/48), 65 percent (31/48), and 37 percent (18/48) of the tumors showed overexpression of Bcl-2, c-Myc, and p53 oncoproteins, respectively. Fifty-four percent (18/33) and 100 percent (9/9) of moderately and poorly differentiated tumors, respectively, were positive for Bcl-2 (P < 0.01). No such correlation was noted for c-Myc and p53 oncoproteins. Univariate analysis showed that patients with Bcl-2 and c-Myc overexpression were associated with poorer overall survival than patients with Bcl-2-negative (P < 0.0124) and c-Myc-negative (P < 0.036) tumors. In addition, when patients were subgrouped according to Dukes stage, a statistically significant poorer overall survival was observed in Dukes C patients with Bcl-2-positive tumors (P < 0.017). Furthermore, multivariate analysis revealed that coexpression of three oncoproteins was predictive of a worse prognosis than for those individuals expressing none of the oncoproteins (P < 0.031) and only one positive oncoprotein (P < 0.014). CONCLUSION: These findings suggest that oncoprotein coexpression possesses significant prognostic and potential therapeutic value; incorporation of molecular markers into future prospective randomized trials is advisable. PMID: 9221853 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 749: Cell Growth Differ. 1997 Jul;8(7):731-42. Regulation of Myc-dependent apoptosis by p53, c-Jun N-terminal kinases/stress-activated protein kinases, and Mdm-2. Yu K, Ravera CP, Chen YN, McMahon G. Oncology Research Program, Preclinical Research, Sandoz Pharmaceuticals Corporation, East Hanover, New Jersey 07936, USA. Deregulated overexpression of c-Myc (Myc) confers susceptibility to apoptosis in several cell types, but the molecular regulation of these processes has not been well established. Here we have characterized several molecular changes that may modulate Myc-dependent apoptosis. Ectopic overexpression of Myc in both Rat1 fibroblasts and human osteosarcoma cells causes a dramatic increase of cellular p53 mRNA and protein, and this induction of p53 correlates with apoptosis triggered by withdrawal of serum. Stable transfection of a wild-type human p53 gene into Myc-transformed cells further potentiates apoptosis. Anticancer agents vinblastine and nocodazole also induce apoptosis in Myc-transformed Rat1 fibroblasts but are cytostatic to the same cells without Myc overexpression. We demonstrate that induction of Myc-dependent apoptosis in these cells is specifically associated with an activation of p46 c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) activity, whereas this JNK/SAPK activation is absent in stress-treated cells without Myc overexpression. Moreover, overexpression of the Mdm-2 gene in Rat1-myc cells significantly inhibits apoptosis induced by low serum but has little effect on apoptosis triggered by chemotherapeutic drugs. Interestingly, differential inhibition by Mdm-2 paralleled differential activation of p46 JNK/SAPK. Thus, our data support a functional involvement of p53 in Myc-dependent apoptosis and implicate potential regulatory roles for JNK/SAPK and Mdm-2 pathways in the regulation of apoptosis in Myc-transformed tumor cells. PMID: 9218867 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 750: Cancer Res. 1997 Jun 15;57(12):2508-15. Role of the p53 tumor suppressor gene in the tumorigenicity of Burkitt's lymphoma cells. Cherney BW, Bhatia KG, Sgadari C, Gutierrez MI, Mostowski H, Pike SE, Gupta G, Magrath IT, Tosato G. Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, MD 20852, USA. Burkitt's lymphoma (BL) cell lines carry a translocated c-myc gene and, in 60-80% of cases, exhibit mutations in the p53 tumor suppressor gene. We examined the potential role of the p53 gene in BL tumorigenicity using an in vitro assay that measures p53-dependent cell cycle arrest in the G1 phase of the cell cycle and an in vivo athymic murine model that detects differences in the tumorigenicity of BL cell lines. A highly significant inverse correlation was found between the ability of BL cells to arrest in G1 after irradiation and their tumorigenicity in athymic mice, consistent with the notion that loss of p53 function is associated with increased tumorigenicity. Inactivation of wild-type (wt) p53 function by expression of the human papillomavirus E6 protein in the AG876V BL cell line, which carries both wt and mutant p53 proteins, rendered the cell line significantly more tumorigenic in athymic mice. Transfection of the wt p53 gene into the p53 mutant and highly tumorigenic BL-41 cell line caused it to acquire wt p53 function and rendered it less tumorigenic in mice. In addition to confirming a role for the loss of p53 function in tumor progression, the data demonstrate that wt p53 protein can reduce BL tumorigenicity in vivo. PMID: 9192833 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 751: Oncogene. 1997 Jun 12;14(23):2825-34. Myc represses the growth arrest gene gadd45. Marhin WW, Chen S, Facchini LM, Fornace AJ Jr, Penn LZ. Department of Molecular and Medical Genetics, University of Toronto, Ontario Cancer Institute, Canada. The c-Myc protein strongly stimulates cellular proliferation, inducing cells to exit G0/G1 and enter the cell cycle. At a molecular level, Myc prevents growth arrest and drives cell cycle progression through the transcriptional regulation of Myc-target genes. Expression of the growth arrest and DNA damage inducible gene 45 (gadd45) is elevated in response to DNA damaging agents, such as ionizing radiation via a p53-dependent mechanism, upon nutrient deprivation, or during differentiation. Gadd45 holds a vital role in growth arrest as ectopic expression confers a strong block to proliferation. Exposure of quiescent cells to mitogen stimulates a rapid increase in c-Myc expression which is followed by the subsequent reduction in gadd45 expression. The kinetics of these two regulatory events suggest that Myc suppresses the expression of gadd45, contributing to G0/G1 phase exit of the cell cycle. Indeed, ectopic Myc expression in primary and immortalized fibroblasts results in the suppression of gadd45 mRNA levels, by a mechanism which is independent of cell cycle progression. Using an inducible MycER system, rapid suppression of gadd45 mRNA is first evident approximately 0.5 h following Myc activation. The reduction in gadd45 mRNA expression occurs at the transcriptional level and is mediated by a p53-independent pathway. Moreover, Myc suppression and p53 induction of gadd45 following exposure to ionizing radiation are non-competitive co-regulatory events. Myc suppression of gadd45 defines a novel pathway through which Myc promotes cell cycle entry and prevents growth arrest of transformed cells. PMID: 9190899 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 752: Biochem Biophys Res Commun. 1997 Jun 9;235(1):153-7. Transcriptional activation of the human c-myc gene by simian virus 40 large T antigen without binding to p53 and RB proteins in the transient expression system. Shimazu T, Takada S, Ishida S, Ueno Y, Koike K. Department of Gene Research, The Cancer Institute, JFCR, Toshima-ku, Tokyo, Japan. Transcriptional activation of the human c-myc gene by SV40 large T antigen was examined using HepG2 cells by co-transfecting a T antigen expression plasmid with a myc-CAT construct containing the 2.3-kb upstream region from the P1 promoter and the P2 promoter region fused to the CAT gene. T antigen increased the basal activity of the P2 promoter region containing the E2F binding site, but both the P2 promoter region and the upstream region from the P1 promoter were important for overall activation by T antigen. CAT assay using mutated T antigen lacking p53 or the RB binding site indicated that p53 or RB was not mainly involved in transcriptional activation of the c-myc gene. It appears that activation of the c-myc gene by T antigen is probably dependent upon E2F and a cellular factor through a mechanism which is independent of binding of T antigen to p53 and RB. PMID: 9196053 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 753: J Pathol. 1997 Jun;182(2):145-50. Cellular kinetic and phenotypic heterogeneity in and among Burkitt's and Burkitt-like lymphomas. Spina D, Leoncini L, Megha T, Gallorini M, Disanto A, Tosi P, Abinya O, Nyong'O A, Pileri S, Kraft R, Laissue JA, Cottier H. Institute of Pathologic Anatomy and Histology, University of Siena, Italy. This study asks whether the known genotypic heterogeneity within and between endemic or sporadic Burkitt's lymphomas (eBLs and sBLs, n = 10 each), and Burkitt-like lymphomas (BLLs, n-12), is reflected in divergent cytokinetics and related immunophenotypes. There was strong evidence that eBL and BLL grow markedly faster than sBL, as shown by differences in mitotic and apoptotic indices. Furthermore, in BLL, the median percentage of neoplastic cells immunoreactive for the bcl-2 protein was much higher than that observed in eBL and sBL. The reverse was true for the median fraction of cells containing c-myc protein. In eBL and sBL, the median fraction of bcl-6 protein-positive cells reached values above 50 per cent, while cells of 8/12 BLLs did not contain detectable amounts of this protein. This observation indicates that in this respect, eBL and sBL resemble normal germinal centres of lymphatic tissue much more than do BLL. Evidence for infection of neoplastic cells by the Epstein-Barr virus (EBV) was observed in 9/10 cases of eBL and in 3/10 of sBL, but not in BLL. EBV-positive lymphomas were associated with distinctly lower apoptotic indices and smaller median percentages of bcl-6-positive cells than EBV-negative tumours. PMID: 9274523 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 754: Pharm World Sci. 1997 Jun;19(3):119-25. Erratum in: Pharm World Sci 1997 Oct;19(5):253. Apoptosis: molecular mechanisms and implications for cancer chemotherapy. Guchelaar HJ, Vermes A, Vermes I, Haanen C. Department of Clinical Pharmacy, Academic Medical Center, University of Amsterdam, The Netherlands. Apoptosis, or programmed cell death, is an orderly and genetically controlled form of cell death. In a morphological sense, it differs from necrosis in that cellular shrinkage and chromatin condensation occurs, followed by fragmentation of nuclear components within membrane-bound vesicles which are cleared by phagocytosis without damage to adjacent tissue. The molecular pathway includes an initiating phase, which starts after signalling by external triggers, such as ligation to distinct receptors or by endogenous mechanisms related to aging or to exogenous irreversible cellular or nuclear damage. The initiation phase is followed by a decision phase. During this phase transduction occurs of the apoptotic signal to nuclear and cytoplasmatic target enzymes, which includes activation of endonucleases and enzymatic alterations of the cytoskeleton. There are numerous proteins and lipid-derived moieties which modulate the apoptotic mechanism in positive or negative direction. The execution phase is started when the cell has arrived at a stage of no return. The nuclear DNA is cleaved into multiples of 180-200 basepairs, the plasma membrane integrity and the mitochondria remain initially intact, the cell splits up into apoptotic bodies, small vesicles which enclose the nuclear and cellular remnants. Finally, the clearing phase is arrived, when the apoptotic bodies are phagocytosed by adjacent cells and macrophages. It is thought that the pharmacodynamics of anticancer drugs consists of two distinct steps. The first step includes the interaction with its cellular target; which is not lethal per se. The commitment of the cell to undergo apoptosis forms the second step. The efficacy of anticancer drugs is determined by the ability to selectively sensitize tumor cells to apoptosis, which depends to a large extent from the expression of various oncogenes, such as bcl-2, p53, bax, ras, c-myc and others, and from endogenous factors. It is a challenge in pharmacological research to explore apoptosis by modulating the extrinsic and intrinsic regulators in a positive or negative direction in order to improve the efficacy of anticancer treatment. Publication Types: Review Review, Tutorial PMID: 9259027 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 755: Mol Mar Biol Biotechnol. 1997 Jun;6(2):88-97. Zebrafish (Danio rerio) p53 tumor suppressor gene: cDNA sequence and expression during embryogenesis. Cheng R, Ford BL, O'Neal PE, Mathews CZ, Bradford CS, Thongtan T, Barnes DW, Hendricks JD, Bailey GS. Department of Food Science and Technology, Oregon State University, Corvallis 97331-6602, USA. Three methods were used in succession to screen a whole adult zebrafish cDNA library for expressed p53-like genes. The sequences of the resultant clones describe an open reading frame 1122 nucleotides in length, with another 43 and 940 bases of 5' and 3' untranslated sequence, respectively. The deduced amino acid sequence of the zebrafish p53 protein is 63% identical to that of trout and 48% identical to that of human p53. Two of the three zebrafish clones overlap to span the entire reported cDNA sequence and are identical in their deduced amino acid sequence over their coincident length. The third clone contains a conservative amino acid change, as well as an inserted amino acid subsequently found to be at the junction of exons 2 and 3, suggestive of alternative splicing in the p53 mRNA for this species. Northern analysis demonstrated a zebrafish p53-related transcript to be present and most abundant in zygotes and early-cleavage embryos less than 1 hour after fertilization, thereafter declining to barely detectable levels at 48 hours. A similar temporal expression was detected for the zebrafish L-myc, known to be present in maternally derived RNA, whereas zebrafish N-myc and the zebrafish homologue of the murine T gene were not detectable prior to the onset of zygotic transcription. PMID: 9200835 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 756: Cancer. 1997 May 15;79(10):1944-50. Progesterone induces apoptosis and up-regulation of p53 expression in human ovarian carcinoma cell lines. Bu SZ, Yin DL, Ren XH, Jiang LZ, Wu ZJ, Gao QR, Pei G. Shanghai Institute of Cell Biology, Chinese Academy of Sciences. BACKGROUND: Progesterone (PROG) has been shown to reduce the risk of developing ovarian carcinoma in postmenopausal women who have undergone estrogen and progestogen replacement therapy, and it has been clinically used to treat some types of ovarian tumors. It is not yet clear whether or not the antitumor activity of progestogen is due to its ability to induce apoptosis in precarcinomatous and carcinomatous ovarian cells. The apoptosis-related genes p53, bcl-2, and c-myc have important roles in the regulation of programmed cell death, and thus may be involved in the process of the suspected PROG-induced apoptosis. METHODS: Antiproliferation effects of PROG on 3AO and AO ovarian carcinoma cells were determined by 3H-thymidine incorporation. Apoptosis of the PROG-treated cells was determined by DNA laddering analysis and was quantitated by both nuclear condensation and flow cytometry after cells were stained with propidium iodide. Cell cycle analysis was also performed by flow cytometry. The expression of p53, bcl-2, and c-myc after 72 hours of PROG treatment was detected by Northern blot analysis. RESULTS: In both 3AO and AO cell lines, cells proliferation was maximally inhibited by PROG after 72 hours of treatment at 10 microM concentration. Under the same conditions, more than 50% of PROG-treated cells had undergone apoptosis, whereas less than 3% of the cells were apoptotic in untreated cell cultures. After exposure to PROG for 72 hours, cells were arrested in the G1 phase of the cell cycle, and the levels of p53 mRNA were remarkably increased in both cell lines. No changes in expression of bcl-2 or c-myc were detected. CONCLUSIONS: PROG significantly inhibited cell proliferation and induced apoptosis in both of the ovarian carcinoma cell lines tested in this study. PROG treatment markedly up-regulated p53 expression in these cells, indicating involvement of p53 in PROG-induced apoptosis. PMID: 9149021 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 757: Gan To Kagaku Ryoho. 1997 May;24 Suppl 1:102-14. Cancer therapy and apoptosis. Inoue S. Department of Environmental Medicine and Informatics, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Japan. Publication Types: Review Review, Tutorial PMID: 9210892 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 758: Photochem Photobiol. 1997 May;65(5):908-14. Gene expression in skin tumors induced in hairless mice by chronic exposure to ultraviolet B irradiation. Sato H, Suzuki JS, Tanaka M, Ogiso M, Tohyama C, Kobayashi S. Kyoritsu College of Pharmacy, Tokyo, Japan. We investigated the expressions of c-Ha-ras, c-jun, c-fos, c-myc genes and p53 protein in the development of skin tumors induced by chronic exposure to UVB without a photosensitizer using hairless mice. When mice were exposed to UVB at a dose of 2 kJ/m2 three times a week, increased c-Ha-ras and c-myc transcripts were detected after only 5 weeks of exposure, while no tumor appeared on the exposed skin. The increase in gene expression continued until 25 weeks, when tumors, identified pathologically as mainly squamous cell carcinomas (SCC), developed in the dorsal skin. In these SCC, overexpression of c-fos mRNA was also observed along with the increases in c-Ha-ras and c-myc. A single dose of UVB (2 kJ/m2) applied to the backs of hairless mice transiently induced overexpression of the early event genes c-fos, c-jun and c-myc, but not c-Ha-ras, in the exposed area of skin. Accumulation of p53 protein was determined by Western blotting analysis or immunohistochemistry using monoclonal antibodies PAb 240 or 246, which recognize mutant or wild type, respectively. In the SCC, a mutant p53 protein accumulated in the cytoplasm and nucleus. After single-dose irradiation, the increased wild-type p53 protein was observed in the nuclei of epidermal cells. The present results suggest that overexpression of the c-fos, c-myc and c-Ha-ras genes, and the mutational changes in p53 protein might be associated with skin photocarcinogenesis. Moreover, overexpression of the c-Ha-ras and c-myc genes might be an early event in the development of UVB-induced skin tumors in mice. PMID: 9155265 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 759: Cancer Genet Cytogenet. 1997 May;95(1):20-32. Advances in the analysis of chromosome alterations in human lung carcinomas. Testa JR, Liu Z, Feder M, Bell DW, Balsara B, Cheng JQ, Taguchi T. Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA. A review of chromosomal analyses of human lung carcinomas is presented. Karyotypic studies have revealed multiple cytogenetic changes in most small cell lung carcinomas (SCLCs) and non-small cell lung carcinomas (NSCLCs). In SCLCs, losses from 3p, 5q, 13q, and 17p predominate; double minutes associated with amplification of members of the MYC oncogene family may be common late in disease. In NSCLCs, deletions of 3p, 9p, and 17p, +7, i(5)(p10), and i(8)(q10) often are reported. The recurrent deletions encompass sites of tumor suppressor genes commonly inactivated in lung carcinomas, such as CDKN2 (9p21), RB1 (13q14), and TP53 (17p13). Despite technical advances in cell culture, the rate of successful karyotypic analysis of lung carcinomas has remained low. Alternative molecular cytogenetic methods to assess chromosome changes in lung cancer, particularly comparative genomic hybridization (CGH) analysis, are discussed. Initial CGH studies confirm the existence of many of the karyotypic imbalances identified earlier in lung cancer and have revealed several recurrent abnormalities, such as 10q- in SCLC, that had not been recognized previously. The further application of such molecular cytogenetic approaches should enable investigators to define more precisely the spectrum and clinical implications of chromosome alterations in lung cancer. Publication Types: Review Review, Tutorial PMID: 9140450 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 760: Cancer Res. 1997 May 1;57(9):1769-75. Low-level c-myc amplification in human colonic carcinoma cell lines and tumors: a frequent, p53-independent mutation associated with improved outcome in a randomized multi-institutional trial. Augenlicht LH, Wadler S, Corner G, Richards C, Ryan L, Multani AS, Pathak S, Benson A, Haller D, Heerdt BG. Department of Oncology, Albert Einstein Cancer Center, Bronx, New York 10467, USA. Human colonic cancer is associated with multiple genetic deletions, mutations, and alterations in gene expression; in contrast, gene amplification has not been recognized as a prominent characteristic of human colonic tumors. Although the c-myc gene is overexpressed in approximately 70% of human colonic cancers, previous studies have not detected frequent gene amplification or rearrangement of c-myc in these tumors, although such amplification has been reported in chemically induced rodent colon cancer and quantitative analysis of gene copy number has shown the gene to be amplified at a low level in mucinous and poorly differentiated human colon carcinomas. Using rigorously controlled blot methodology, we have established that the c-myc gene, located at 8q21, exhibited amplification of 87% to 35-fold in 7 of 10 human colonic carcinoma cell lines. This was highly significant even at a low level of amplification in HT29 cells (P < 0.0001). Cytogenetic analysis by G-banding did not detect aneuploidy involving chromsome 8q, suggesting that the amplification for the c-myc gene on 8q was relatively specific, and this was consistent with a lack of amplification detected for the c-mos gene on 8q24, which was assayed similarly. The same methodology then revealed amplification of c-myc from 1.5-fold to 5-fold in 32% of tumors from 149 patients entered into a multi-institutional Phase III study of adjuvant therapy for colon cancer. c-myc status was not related to time to recurrence or death, but low levels of c-myc amplification identified a subset of patients who showed a statistically significant increase in disease-free survival, and a corresponding trend to longer overall survival, in response to adjuvant therapy with 5-fluorouracil plus levamisole. Presence of c-myc amplification was not related to incidence of p53 mutations. Publication Types: Clinical Trial Multicenter Study Randomized Controlled Trial PMID: 9135021 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 761: J Virol. 1997 May;71(5):3940-52. Low-frequency loss of heterozygosity in Moloney murine leukemia virus-induced tumors in BRAKF1/J mice. Lander JK, Fan H. Department of Molecular Biology and Biochemistry, University of California, Irvine 92717, USA. To identify potential involvement of tumor suppressor gene inactivation during leukemogenesis by Moloney murine leukemia virus (M-MuLV), a genome-wide scan for loss of heterozygosity (LOH) in tumor DNAs was made. To assess LOH, it is best to study mice that are heterozygous at many loci across the genome. Accordingly, we generated a collection of 52 M-MULV-induced tumor DNAs from C57BR/cdJ x AKR/J F1 (BRAKF1) hybrid mice. By using direct hybridization with oligonucleotides specific for three different classes of endogenous MuLV-related proviruses, 48 markers on 16 of 19 autosomes were simultaneously examined for allelic loss. No allelic losses were detected, with the exception of a common loss of markers on chromosome 4 in two tumors. The three autosomes that lacked informative endogenous proviral markers were also analyzed for LOH by PCR with simple-sequence length polymorphisms (SSLPs); one additional tumor showed LOH on chromosome 15. Further screening with chromosome 4 SSLPs identified one additional tumor with LOH on chromosome 4. Therefore, in total, the average fractional allelic loss was quite low (0.002), but the LOH frequency of 6% on chromosome 4 was highly statistically significant (P < 0.0005). Detailed SSLP mapping of the three tumors with LOH on chromosome 4 localized the region of common LOH to the distal 45 centimorgans, a region syntenic with human chromosomes 1 and 9. Candidate tumor suppressor genes, Mts1 (p16INK4a) and Mts2 (p15INK4b), have been mapped to this region, but by Southern blot analysis, no homozygous deletions were detected in either gene. One of three tumors with LOH on chromosome 4 also showed a proviral insertion near the c-myc proto-oncogene. These results suggested that tumor suppressor inactivation is generally infrequent in M-MuLV-induced tumors but that a subset of these tumors may have lost a tumor suppressor gene on chromosome 4. PMID: 9094671 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 762: Biochem Biophys Res Commun. 1997 Apr 28;233(3):700-6. The expression of genes modulating programmed cell death in normal human polymorphonuclear neutrophils. Hsieh SC, Huang MH, Tsai CY, Tsai YY, Tsai ST, Sun KH, Yu HS, Han SH, Yu CL. Department of Medicine, Veterans General Hospital, Taipei, Taiwan, Republic of China. Normal human polymorphonuclear neutrophils (PMN) have a short life and die in progression via apoptosis. In order to understand the molecular basis of PMN apoptosis, the expression of apoptosis-related (Fas, Fas-ligand, p53, and c-myc) and survival-related (bcl-2) genes was detected by flow cytometry, Western blot and reverse transcription-assisted polymerase chain reaction (RT-PCR). We found that Fas and Fas-ligand (FasL) were expressed on the surface of most of the cells. However, the disappearance of FasL was much faster than Fas after 24 h incubation. p53 and bcl-2 were also expressed in the cytoplasm of most of the cells. In contrast, the expression of c-myc was negligible in PMN. The addition of monoclonal anti-human Fas antibody (25 micrograms/ml) to PMN suspension enhanced whereas anti-FasL antibody (25 micrograms/ml) suppressed PMN apoptosis in 48 h incubation. These results suggest that the activation of Fas pathway induced by Fas-FasL interaction among PMNs is one of the mechanisms for spontaneous PMN apoptosis. Lack of proto-oncoprotein c-myc expression in PMN is responsible for their non-proliferative property and may aggravate the spontaneous apoptosis of the cells. PMID: 9168918 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 763: J Biol Chem. 1997 Apr 25;272(17):10983-6. Transcriptional repression of p53 promoter by hepatitis C virus core protein. Ray RB, Steele R, Meyer K, Ray R. Division of Infectious Diseases and Immunology, Saint Louis University, St. Louis, Missouri 63110, USA. Our previous results have suggested that the putative core protein of hepatitis C virus (HCV) transcriptionally regulates cellular and viral genes, inhibits cisplatin and c-myc-mediated apoptotic cell death under certain conditions, and transforms primary rat embryo fibroblast cells with a cooperative oncogene. Because HCV appears to cause hepatocellular carcinoma, we evaluated the regulatory role of the HCV core protein on p53, a well known tumor suppressor gene, by an in vitro transfection assay. HCV core protein repressed transcriptional activity of the p53 promoter when tested separately in COS7 and HeLa cells. Deletion mutational analysis of the HCV core gene indicated that the regulatory domain involved in the repression of p53 transcriptional activity is located around amino acid residues 80-122 encompassing a putative DNA binding motif and two major phosphorylation sites. Results from this study suggest that the putative core protein may have an important biological role in the promotion of cell growth by repressing p53 transcription, and this appears to be consistent with certain earlier observations about HCV core moving into the nucleus. PMID: 9110985 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 764: FEBS Lett. 1997 Apr 7;406(1-2):17-22. On the involvement of calpains in the degradation of the tumor suppressor protein p53. Gonen H, Shkedy D, Barnoy S, Kosower NS, Ciechanover A. Department of Biochemistry, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa. A crude fraction that contains ubiquitin-protein ligases contains also a proteolytic activity of approximately 100 kDa that cleaves p53 to several fragments. The protease does not require ATP and is inhibited in the crude extract by an endogenous approximately 250 kDa inhibitor. The proteinase can be inhibited by chelating the Ca2+ ions, by specific cysteine proteinase inhibitors and by peptide aldehyde derivatives that inhibit calpains. Purified calpain demonstrates an identical activity that can be inhibited by calpastatin, the specific protein inhibitor of the enzyme. Thus, it appears that the activity we have identified in the extract is catalyzed by calpain. The calpain in the extract degrades also N-myc, c-Fos and c-Jun, but not lysozyme. In crude extract, the calpain activity can be demonstrated only when the molar ratio of the calpain exceeds that of its native inhibitor. Recent experimental evidence implicates both the ubiquitin proteasome pathway and calpain in the degradation of the tumor suppressor, and it was proposed that the two pathways may play a role in targeting the protein under various conditions. The potential role of the two systems in this important metabolic process is discussed. PMID: 9109377 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 765: Leukemia. 1997 Apr;11 Suppl 3:387-8. Granulocyte-colony stimulating factor induced apoptosis in radiation-induced murine leukemia cell line. Handa A, Kashimura T, Kawano N, Yamamoto A, Yoshida S, Jinnai I, Murohashi I, Bessho M, Hirashima K. Department of 1st Internal Medicine, Saitama Medical School, Japan. Cytokines regulate proliferation and differentiation of hematopoietic progenitor cells. Recently it has been clarified that physiological cell death, apoptosis plays important role of hematopoiesis. So we evaluated the effects of granulocyte-colony stimulating factor (G-CSF) on leukemic cells, especially focused on apoptosis. Intravenous inoculation of radiation-induced murine leukemia cell line, C2M-A5 into the parent C3H mice resulted in the development of myeloid leukemia. However, the leukemic death of the mice was completely suppressed by the daily subcutaneous injection of recombinant human (rh)G-CSF from the next day (Bessho M. et al., Leuk Res 1989:13:1001-1007). In the in vitro study using C2M-A5 cells, we found that apoptosis appears on the cells at 48 hours after addition of G-CSF in culture. The cells in this stage lost the leukemogenicity to C3H mice (Bessho M. et al., Leukemia 8:1185-1190:1994). To clarify the mechanism of the induction of apoptosis by G-CSF we studied cell cycle and molecular changes in C2M-A5 cells cultured in medium with or without rhG-CSF by means of using the flowcytometry and Northern and Western blot analyses. After addition of rh G-CSF to culture, C2M-A5 cells removed to S phase, next arrested at G0/G1 phase on and after 24 hours, and 48 hours later, apoptosis was observed. Overexpression of mRNAs for c-myc (3-24 hours later) and for p53 (6-24 hours later), were observed in the cell cultured in rhG-CSF administered medium with a concomitant down-expression of bcl-2 mRNA (from 6 hours later). Tyrosine-phosphorylated protein (17 kd) appeared at 48 hours after administration of rhG-CSF to cell culture. This protein was suggested for specific apoptosis induction by rhG-CSF. These results are summarized as follows. (1) rhG-CSF induced apoptosis to C2M-A5 and deprived its leukemogenicity to mice. (2) Induction of apoptosis was associated with cell cycle and correlated to the changes of the expression rates of c-myc,p53, and bcl-2. (3) Tyrosine kinase may play an important role in apoptosis induction to C2M-A5 by rhG-CSF. PMID: 9209400 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 766: Leukemia. 1997 Apr;11 Suppl 3:337-9. p53 mediated apoptosis in HeLa cells: transcription dependent and independent mechanisms. Haupt Y, Rowan S, Shaulian E, Kazaz A, Vousden K, Oren M. Weizmann Institute of Science, Rehovot, Israel. The most frequent target for genetic alterations in human cancers is the p53 tumor suppressor gene. Mutations in p53 abrogate its ability to inhibit cell growth and to suppress tumor progression. The anti-proliferative activity of p53 can be mediated by the induction of growth arrest and/or programmed cell death (apoptosis). Recent in vivo studies support the involvement of apoptosis in tumor suppression by p53. To gain further insight into the mechanisms by which p53 induces apoptosis, the activity of p53 was studied in HeLa cells using a transient transfection assay. To define the functional domains of p53 required for apoptosis a C-terminal deletion mutant of p53 was used. This mutant, p53d1214, lacks the oligomerization domain, the nuclear localization signal and a large part of the core DNA binding domain. This mutant was shown to be deficient in sequence specific transactivation activity. Overexpression of wt p53 induced an efficient apoptosis in transiently transfected HeLa cells. Surprisingly p53d1214, containing only the first 214 N-terminal residues induced extensive apoptosis. The induction of apoptosis by p53d1214 is slower than that induced by wt p53. Furthermore, p53d1214 suppressed the transformation of rat embryo fibroblasts by several oncogene combinations, such as myc plus ras. In view of the fact that p53d1214 lacks measurable transactivation potential, our findings suggest the existence of two p53 dependent-apoptotic pathways--one involves activation of specific target genes, and the other is independent of it. Transactivation independent apoptosis may play a central role in tumor suppression by p53. PMID: 9209383 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 767: Immunol Invest. 1997 Apr;26(3):351-70. An RGD containing peptide from HIV-1 Tat-(65-80) modulates protooncogene expression in human bronchoalveolar carcinoma cell line, A549. el-Solh A, Kumar NM, Nair MP, Schwartz SA, Lwebuga-Mukasa JS. Department of Internal Medicine, SUNY at Buffalo School of Medicine and Biomedical Sciences, Buffalo General Hospital 14203, USA. Tat (transactivator of transcription) is essential for HIV-1 replication in vivo and in vitro. Tat-(65-80), an RGD containing domain, has been shown to regulate proliferative function of a variety of cell lines, including a human adenocarcinoma cell line, A549. The exact cellular and molecular mechanisms by which these effects are mediated, remain unknown. To evaluate the hypothesis that Tat-(65-80) modulates the expression of immediate early genes (IEG) c-jun, c-myc, c-fos and the tumor suppressor gene p53, serum starved A549 cells were incubated with Tat-(65-80) or heat-inactivated Tat-(65-80) at 10 ng/ml. Total cellular RNA was isolated from the cells at various time points (0-24 hours). In each case, 5 micrograms of RNA was reverse transcribed in 20 microliters of reaction volume. Equal amounts of cDNA were subjected to polymerase chain reaction (PCR) and analyzed by electrophoresis. The photographic negatives of the ethidium bromide stained gels were quantitated by densitometric scanning and normalized to corresponding beta-actin PCR products. Treatment with Tat-(65-80) showed a twofold induction of c-jun at 0.5 h. Peak expression occurred at 60 minutes and remained above baseline at 24 hours (h). c-myc was increased at 0.5 h, reached a twofold increase at 2 h and remained above baseline at 24 h. c-fos increased seven fold at 0.5 h and declined subsequently to baseline at 8 h. p-53 gene was reduced fivefold at 0.5 h and remained downregulated thereafter. These results show that Tat-(65-80) can modulate growth related genes in human lung epithelial cells. PMID: 9129988 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 768: Proc Soc Exp Biol Med. 1997 Apr;214(4):359-66. High-level expression of H-ras and c-myc oncogenes in mycoplasma-mediated malignant cell transformation. Zhang B, Shih JW, Wear DJ, Tsai S, Lo SC. Department of Infectious and Parasitic Disease Pathology, Armed Forces Institute of Pathology, Washington, District of Columbia 20306-6000, USA. C3H mouse embryo cells, which normally have low inherent spontaneous transformation, underwent malignant transformation while chronically infected with Mycoplasma fermentans or Mycoplasma penetrans. This mycoplasma-mediated oncogenic process had long latency (more than 7 weeks of persistent mycoplasmal infection) and showed multistage progression characterized by reversibility and irreversibility of malignant properties upon removal of M. fermentans from culture. Marked expression of H-ras and c-myc mRNA, but not N-myc, src, N-ras, or p53 mRNA, was found in the mycoplasma-transformed C3H cells that exhibited characteristic malignant properties of morphological changes and uncontrolled cell growth. However, at least up to the eleventh week of persistent mycoplasma infection, the marked expression of H-ras or c-myc mRNA in C3H cells depended on continued presence of the mycoplasma in culture. H-ras or c-myc mRNA rapidly declined to the undetectable low levels of nontransformed parental C3H cells, and all malignant properties of the once-fully-transformed C3H cells quickly reversed, if M. fermentans was eradicated from culture. In comparison, infection with M. penetrans for 7 or 11 weeks also induced a high level of H-ras, but not c-myc, mRNA expression in C3H cells. Despite having prominent amount of steady-state H-ras mRNA, these M. penetrans-infected C3H cells did not show any sign of malignant transformation. Thus, marked expression of H-ras gene alone was not sufficient to effect transformation in C3H cells. Interestingly, after a further prolonged (18 weeks) infection with either M. fermentans or M. penetrans, C3H cells revealed prominent chromosomal changes, expressed constitutively (with or without the presence of the transforming mycoplasmas) at high levels of both H-ras and c-myc mRNA and became permanently transformed. These cells were able to form tumors in animals. PMID: 9111527 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 769: Hepatology. 1997 Apr;25(4):874-83. Hepatocarcinogenesis in woodchuck hepatitis virus/c-myc mice: sustained cell proliferation and biphasic activation of insulin-like growth factor II. Liu P, Terradillos O, Renard CA, Feldmann G, Buendia MA, Bernuau D. Laboratoire de Biologie Cellulaire, INSERM U 327, Faculte de Medecine X. Bichat, Paris, France. Transgenic mice carrying the c-myc oncogene under control of woodchuck hepatitis virus (WHV) DNA sequences invariably develop hepatocellular carcinoma (HCC), despite a temporally limited expression of the transgene in the neonatal liver. To better characterize the different steps of the tumorigenic process, we analyzed the liver expression of the c-myc transgene and several growth-related genes by in situ hybridization and Northern blotting. In parallel studies, proliferated changes were investigated by detection of bromodeoxy-uridine-positive S-phase nuclei and apoptosis was evaluated by in situ nick end-labeling of DNA. During the neonatal period, high levels of c-myc messenger RNAs (mRNAs) were detected in all hepatocytes, and the expression of insulin-like growth factor II (IGF II) was frequently enhanced, correlating with increased cell proliferation. Despite elevated expression of the p53 gene, no change in liver cell apoptosis was observed. After weaning, c-myc transgene expression decreased to undetectable levels in all hepatocytes, whereas proliferation decreased but remained notably higher than in age-matched controls. The expression of c-fos, c-jun, and c-H-ras was highly variable during the preneoplastic period and in the tumors, with no consistent increase compared with controls. Resurgence of c-myc transgene expression was evidenced in all cells from hyperplastic lesions and carcinomas, accompanied with frequent focal reactivation of IGF II. Thus the strong proliferative stimulus induced by the combined effects of c-myc and IGF II in the neonatal liver might initiate a process characterized by persistent, dysregulated hepatocyte proliferation, in turn greatly increasing the risk of hepatocellular transformation. PMID: 9096591 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 770: In Vivo. 1997 Mar-Apr;11(2):157-61. Interferons alpha, beta and gamma induce different patterns of gene expression in cultured human epidermal keratinocytes. Arany I, Arany M, Brysk H, Tyring SK, Brysk MM. Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555-1019, USA. Differences in the effects on confluent epidermal keratinocytes of treatment with interferons (IFNs) alpha, beta, and gamma were observed in their modulation of the mRNA levels of representative structural and functional cellular proteins. Comparisons of the responses in culture media with varying cellular maturation potential indicated the dependence of the modulation on the stage of differentiation. Differentiation was correlated with upregulation of all the genes by interferon gamma, but this effect was not seen with the other interferons. Even though IFNs alpha and beta share the same cell surface receptor, their effects on gene expression were clearly distinguishable and varied with the culture medium. These findings might have relevance in the treatment of skin lesions with varying degrees of differentiation. PMID: 9179609 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 771: Gynecol Oncol. 1997 Mar;64(3):526-32. Merkel cell carcinoma of the vulva. Gil-Moreno A, Garcia-Jimenez A, Gonzalez-Bosquet J, Esteller M, Castellvi-Vives J, Martinez Palones JM, Xercavins J. Department of Gynecologic Surgery/Gynecologic Oncology, Hospital Universitario Materno-Infantil Vall d'Hebron, Barcelona, Spain. Merkel cell carcinoma is a very rare tumor. This is why it is not known whether this neoplasm behaves differently in the vulvar location than at other sites. We present a patient with a Merkel cell carcinoma assessed with a light optical microscope, immunohistochemistry, and electron microscope. Only eight previous cases have been reported in the literature. We discuss pathologic findings, such as histologic trabecular pattern under the optical microscope and neurosecretory granules (similar to Merkel cell carcinoma of the skin) under the electron microscope. Also discussed are the results of immunohistochemistry for low-molecular-weight cytokeratin, neuron-specific enolase, chromogranin, and Leu 7, and molecular study of N-ras, K-ras, N-myc, and p53 genes. Little is known about Merkel cell carcinoma of the vulva, but it seems to have a more aggressive behavior and poorer prognosis than Merkel cell carcinoma at other sites. Publication Types: Case Reports Review Review of Reported Cases PMID: 9062165 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 772: Cell Growth Differ. 1997 Mar;8(3):343-52. Induction of apoptosis and inhibition of cell growth are independent responses to interferon-alpha in hematopoietic cell lines. Sangfelt O, Erickson S, Castro J, Heiden T, Einhorn S, Grander D. Department of Oncology/Pathology, Karolinska Hospital and Institute, Stockholm, Sweden. IFNs are capable of modulating a variety of cellular responses, including cell growth and apoptosis. The prospective connections between these two biological responses are not fully understood, and the molecular mechanisms underlying the effects of IFNs on these processes are not completely defined. We have investigated the relationship between IFN-alpha-induced apoptosis and cell cycle arrest in three hematopoietic cell lines, Daudi, U-266, and H9. It was found that IFN-alpha was a rapid and potent inducer of apoptosis in H9 and U-266 cells, whereas IFN-alpha-induced cell cycle arrest in Daudi cells is not associated with the onset of apoptosis. In H9 cells, apoptosis occurs without a preceding cell cycle block, whereas in U-266 cells, apoptosis occurs subsequent to G1 arrest. Cell cycle arrest per se, induced by serum starvation or treatment with aphidicolin, had only minor effects on the viability of these cell lines and did not abrogate the apoptosis-inducing capacity of IFN-alpha. Additionally, IFN-alpha-induced apoptosis occurred in cells from all cell cycle phases. Thus, we conclude that IFN-alpha-induced apoptosis seems to occur independent of cell growth inhibition. There were no changes in Bcl-2 or Bax protein levels that could account for the apoptosis-inducing effects of IFN-alpha in these cell lines. Moreover, examination of p53 status suggests that IFN-alpha-induced apoptosis in the U-266 and H9 cell lines occurs through a p53-independent pathway. PMID: 9056677 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 773: Hum Pathol. 1997 Mar;28(3):367-74. AIDS-related primary brain lymphomas: histopathologic and immunohistochemical study of 51 cases. The French Study Group for HIV-Associated Tumors. Camilleri-Broet S, Davi F, Feuillard J, Seilhean D, Michiels JF, Brousset P, Epardeau B, Navratil E, Mokhtari K, Bourgeois C, Marelle L, Raphael M, Hauw JJ. Departement de Neuropathologie, INSERM U360, CNRS URA 625, CHU Pitie-Salpetriere, Paris, France. Fifty-one cases of acquired immunodeficiency syndrome (AIDS)-related primary brain lymphomas (AR-PBL) were investigated for clinical characteristics; human immunodeficiency virus (HIV)-associated disorders; histopathologic features; immunophenotype; Epstein-Barr virus (EBV) infection; and, when frozen tissue was available, oncogene rearrangements. AR-PBL occurred late in the course of AIDS and were usually associated with other systemic or cerebral disorders and with a low level of CD4 lymphocytes. All cases were high grade lymphomas according to the Working Formulation or updated Kiel classification, and often displayed a multifocal pattern. Thirty cases were classified as immunoblastic with plasmacytic differentiation, 18 cases were large cell lymphomas with an immunoblastic component or centroblastic polymorphic lymphomas, and 2 were small noncleaved non-Burkitt lymphomas (Working Formulation). This latter category is classified as Burkitt's-like lymphoma in the REAL nomenclature. One case could not be classified because of necrosis. AR-PBL showed a high level expression of activation and adhesion molecules. The presence of EBV was detected in most cases, and, when PCR was used, this was a constant finding. bcl-2 oncoprotein and latent membrane protein-1 (LMP-1) were strongly expressed. None of the tested cases expressed p53, or were rearranged for bcl-2 or c-myc oncogenes. This study confirms the immunophenotypic specificity of AR-PBL, which may reflect the special immune status of the brain. PMID: 9042803 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 774: Cancer Res. 1997 Mar 1;57(5):900-6. Prostate cancer progression, metastasis, and gene expression in transgenic mice. Perez-Stable C, Altman NH, Mehta PP, Deftos LJ, Roos BA. Veterans Affairs Medical Center, and Department of Medicine, University of Miami School of Medicine, Florida 33101, USA. We previously reported that a transgenic mouse line containing the fetal globin promoter linked to the SV40 T antigen (T Ag) viral oncogene (Ggamma/T-15) resulted in prostate tumors. In this study, we further explored tumor origin, frequency, invasiveness, androgen sensitivity, and gene expression pattern. T Ag was detected in adult but not fetal and neonatal prostates, suggesting a role for androgens in tumor progression. However, castration shortly after prostate morphogenesis did not prevent tumor development, suggesting an androgen-independent phenotype. Tumors originated within ventral or dorsal prostate lobes and involved intraepithelial neoplasia, rapid growth in the pelvic region, and metastasis to lymph nodes and distant sites. In addition, the primary cancers could be propagated in nude mice or nontransgenic mice. Seventy-five percent of hemizygous and 100% of homozygous transgenic males developed prostate tumors, suggesting a T Ag dosage effect. Biochemical characterization of advanced tumors revealed markers of both neuroendocrine and epithelial phenotypes; markers of terminal differentiation are lost early in tumorigenesis. Tumor suppressor genes (p53 and Rb), normally bound to T Ag, were up-regulated; bcl-2 proto-oncogene, which prevents apoptosis, was slightly up-regulated. Myc, a stimulus to cell cycle progression, was unchanged. We propose the Ggamma/T-15 transgenic line as a model of highly aggressive androgen-independent metastatic prostate carcinoma with features similar to end-stage prostate cancer in humans. PMID: 9041192 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 775: Pathol Int. 1997 Feb-Mar;47(2-3):90-4. Apoptosis and proliferative activity of non-Hodgkin's lymphomas: comparison with expression of bcl-2, p53 and c-myc proteins. Takano Y, Saegusa M, Ikenaga M, Okayasu I. Department of Pathology, Kitasato University, School of Medicine, Sagamihara, Japan. In order to clarify the role of spontaneous apoptosis of non-Hodgkin's lymphomas in the growth regulation system, apoptotic indices (AI) assessed by DNA nick end-labeling and proliferative activity, estimated in terms of KI-67 labeling indices (KI) and mitotic indices (MI), were compared. In addition, expression of bcl-2, p53 and c-myc was also examined in relation to these indicators. For this study, 103 lymphoma cases were used, comprising 72 of B cell and 31 of T cell origin (42 nodal and 62 extranodal). AI, KI and MI were significantly increased in line with bcl-2 negativity and p53 positivity, and there was no relation to the T, B cell classification or expression of c-myc. These indicators positively correlated overall. Positive correlation was stricter in groups believed to represent a good prognostic predictive factor, such as B cell origin, bcl-2(+), p53(-) and c-myc(-). Significant cross-correlation was noted only between bcl-2 versus T, B cell classification. However, no inverse correlation between bcl-2 and p53 was evident. These results suggest, in non-Hodgkin's lymphomas, that apoptosis plays an important role together with proliferative activity in counter-balancing tumor volume, and is strictly linked to bcl-2 expression, less so to p53 expression, but independent of T, B cell classification and c-myc expression. Apoptotic indices may be a predictive indicator for prognosis similar to proliferative activity. PMID: 9088026 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 776: Biochem Mol Biol Int. 1997 Feb;41(2):279-84. Detection of apoptosis in the brain of the zitter rat with genetic spongiform encephalopathy. Ookohchi T, Ito H, Serikawa T, Sato K. Department of Molecular Biology, Faculty of Medicine, Tottori University, Yonago, Japan. Zitter rat develops genetic spongiform encephalopathy accompanied with whole-body tremors and flaccid paresis. To elucidate the mechanism of a neuronal cell death in the brain, we determined involvement of apoptosis in this rat. By Northern blot analysis, the elevation of mRNA levels were observed in c-jun, c-fos, c-myc and p53 genes which were induced by apoptotic signals: conversely, expression of bcl-2 was shown to be decreased in the zitter rat brain in contrast to the WTC control rat. Furthermore, TUNEL staining of fragmented DNA indicated apoptotic morphology in this brain. These results strongly suggested that the spongiform encephalopathy of the zitter rat was due to apoptosis in the brain cells. PMID: 9063567 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 777: Mol Carcinog. 1997 Feb;18(2):66-77. Upregulation of endogenous p53 and induction of in vivo apoptosis in B-lineage lymphomas of E(mu)-myc transgenic mice by deregulated c-myc transgene. Prasad VS, LaFond RE, Zhou M, Jacobsen KA, Osmond DG, Sidman CL. Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Ohio 45267, USA. E(mu)-myc transgenic mice carry a constitutively overexpressed c-myc oncogene and develop B-lineage lymphomas. Previous studies have shown that c-myc overexpression can lead to in vitro apoptosis. Here, we investigated the in vivo effects of altered c-myc expression on cell proliferation versus death in spontaneously arising E(mu)-myc tumors. E(mu)-myc tumors display extensive in vivo apoptosis confined to small clusters of cells with greatly increased expression of both the c-myc transgene and the endogenous p53 gene as compared with that in normal, pretumor, or surrounding tumor tissue. This restricted overexpression of both the c-myc transgene and the endogenous p53 gene in small clusters of apoptotic tumor cells indicates that overexpression of these genes and apoptosis are not obligatory or uniform during tumor development and suggests that further somatic mutations or microenvironmental influences may be responsible for these properties. Nevertheless, the clear ability of tumor cells to undergo apoptosis in vivo may be exploitable for therapeutic purposes. PMID: 9049182 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 778: Leukemia. 1997 Feb;11(2):253-7. Co-expression of several molecular mechanisms of multidrug resistance and their significance for paclitaxel cytotoxicity in human AML HL-60 cells. Huang Y, Ibrado AM, Reed JC, Bullock G, Ray S, Tang C, Bhalla K. Division of Hematology/Oncology, Department of Medicine and Winship Cancer Center, Emory University School of Medicine, Atlanta, GA 30322, USA. Overexpression of P-glycoprotein (PGP), MRP or LRP has been characterized as the 'proximal', while overexpression of the anti-apoptosis Bcl-2 or Bcl-xL relative to the pro-apoptosis Bax protein has been recognized as the 'distal' mechanism of multidrug resistance in human AML cells. In the present studies, we examined whether these mechanisms can co-exist in human AML HL-60 cells. We also determined how these mechanisms would affect the accumulation and cytotoxicity of a PGP substrate, such as Taxol (paclitaxel). For this, immunoblot analyses were performed to determine the expression of PGP, MRP, Myc, Bcl-2, Bcl-xL and Bax on either the multidrug-resistant HL-60 sublines created under the selection pressure of doxorubicin (HL-60/AR), paclitaxel (HL-60/TAX1000) or vincristine (HL-60/VCR), or sublines created by transfection and overexpression of the bcl-2 (HL-60/Bcl-2) or bcl-xL gene (HL-60/Bcl-xL). As compared to the control HL-60, HL-60/AR cells possess high MRP while HL-60/TAX1000 and HL-60/VCR cells express high levels of the mdr-1 encoded PGP. In addition, these multidrug-resistant cells possess 1.5- to 2.5-fold higher Bcl-2, while their Bax and Myc levels are similar to those in the control HL-60 cells. HL-60/TAX1000 and HL-60/VCR cells also express three- and 2.5-fold higher Bcl-xL levels. PGP, but not MRP, overexpression significantly impaired paclitaxel accumulation and paclitaxel-induced apoptosis, as well as reduced its cytotoxic effects as determined by the MTT assay. In contrast, enforced and much higher expression of Bcl-2 in HL-60/Bcl-2 (five-fold) or Bcl-xL in HL-60/Bcl-xL cells (10-fold) significantly reduced paclitaxel-induced apoptosis and the loss of cell viability, without affecting its intracellular accumulation. These results confirm the possibility of co-expression of multiple mechanisms of multidrug resistance in human leukemic cells which had been selected by exposure to a single drug. The results also indicate that MRP overexpression does not confer resistance against paclitaxel. In addition, these findings suggest that, for Bcl-2 and Bcl-xL, enforced overexpression to high levels is necessary to induce paclitaxel resistance in HL-60 cells. PMID: 9009089 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 779: Radiat Res. 1997 Feb;147(2):156-65. Further investigation of the response of human uroepithelium to low doses of cobalt-60 gamma radiation. Mothersill C, O'Malley K, Harney J, Lyng F, Murphy DM, Seymour CB. Department of Physics, Dublin Institute of Technology, Ireland. Explant cultures of normal human uroepithelium were established, exposed to a range of 60Co gamma-ray doses from 0.1-5 Gy and grown for 14 days. Expression of Myc, p53 and Bc12 proteins in the epithelial cells which grew from irradiated explants was measured in situ using immunocytochemistry. The results show that overexpression of Bc12 with low Myc expression correlated with resistance to radiation as shown by the extent of growth detected on day 14. Strong staining for Myc coupled with low or absent Bc12 expression generally correlated with radiosensitivity, although the level of p53 of the culture was critical in these cases. None of the proteins on their own correlated with radiation response. What appeared to be critical was the balance of cells expressing Bc12 and Myc proteins. Building on the results presented in a previous paper which showed a division of cultures from patients into those showing monotonic and nonmonotonic responses, this study presents results for explant cultures from a greater number of patients and attempts to characterize the profile of expression of the above proteins in the uroepithelium of these patients. It shows that high Bc12/Myc ratios were found in cultures which showed a non-monotonic and resistant dose response. Where Myc was the dominant protein in the culture postirradiation, a radiosensitive and monotonic response tended to occur. Since the proteins are being detected in the distant progeny of irradiated cells, it is likely that changes induced by radiation in the cell population are stable. The measurement of these two proteins can be made in cultured biopsy material and may therefore have predictive value in radiotherapy and radiation protection. Both normal and tumor biopsies from bladder mucosa showed similar correlations between Bc12/Myc ratios and growth postirradiation. PMID: 9008207 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 780: Cancer Lett. 1997 Jan 15;112(1):65-9. Selective hyperexpression of c-jun oncoprotein by glass fiber- and silica-transformed BALB/c-3T3 cells. Gao H, Brick J, Ong S, Miller M, Whong WZ, Ong T. West Virginia University, Morgantown 26506, USA. Mining and mineral processing are important industries in the United States. A large number of workers are potentially exposed to silica during mining and to glass fibers during manufacturing. There is a concern regarding lung cancer risk among workers exposed to silica and glass fibers. Our previous studies showed that both glass fibers and silica induced transformation of BALB/c-3T3 cells. In order to explore the relationship between silica and glass fiber-induced cell transformation and oncoprotein expression, the protein products of seven proto-oncogenes (c-K-ras, c-H-ras, c-sis, c-myc, c-myb, c-erb B1 and c-jun) and one tumor suppressor gene (p53) were examined in BALB/c-3T3 cells transformed by glass fibers or silica using immunoblotting with specific monoclonal or polyclonal antibodies. The results showed that all transformants, including eight induced by glass fibers and eight by silica (Min-U-Sil 5), were positive for c-jun protein expression; the level of c-jun protein was elevated 8-21-fold in these transformants. Other protooncogene proteins in transformed cells were either not detectable or not different from non-transformed cells. These results suggest that the overexpression of c-jun is common in BALB/c-3T3 transformed cells induced by glass fibers or silica. It seems, therefore, that the expression of c-jun may play an important role in the transformation process. PMID: 9029170 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 781: Cancer Lett. 1997 Jan 15;112(1):33-45. Highly metastatic hepatocellular carcinomas induced in male F344 rats treated with N-nitrosomorpholine in combination with other hepatocarcinogens show a high incidence of p53 gene mutations along with altered mRNA expression of tumor-related genes. Masui T, Nakanishi H, Inada K, Imai T, Mizoguchi Y, Yada H, Futakuchi M, Shirai T, Tatematsu M. Laboratory of Pathology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Japan. The carcinogenic and metastatic processes are thought to consist of a sequence of steps, and animal models featuring highly metastatic lesions are clearly necessary to allow analysis of the whole process of transformation from preneoplastic changes to high grade metastatic tumors, and to access effectiveness of therapeutic treatments of advanced cancers in vivo. The purpose of the present study was to establish a model and to screen for reported genetic alterations in induced lesions. In the present study, it was confirmed that lung metastasis of hepatocellular carcinomas (HCCs) induced in male F344 rats by N-nitrosomorpholine (NNM), given in the drinking water at a dose of 120 ppm for 24 weeks, was significantly enhanced by additional carcinogenic pretreatments and that a single i.p. injection of 100 mg/kg body weight N-diethylnitrosamine (DEN) alone was sufficient for that purpose. Molecular biological analyses of the induced lesions revealed point mutations in the p53 gene in 60.9% of HCCs, and elevated expression of mRNAs for p53, c-myc, c-fos, TGF-alpha, TGF-beta1, alpha-fetoprotein, GST-P, and GGT, and decreased mRNA expression of EGF and EGFR in HCCs when compared to controls. No obvious association of gene alterations with metastatic potential of primary tumors was found except for an increase in the incidence of p53 mutations. Since the process of metastasis is thought to be sequential and selective, further comparative analysis of metastatic and primary lesions should clarify the mechanisms involved in the multi-step process of metastasis. PMID: 9029167 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 782: Cancer Res. 1997 Jan 15;57(2):320-5. Defects in p21WAF1/CIP1, Rb, and c-myc signaling in phorbol ester-resistant cancer cells. Blagosklonny MV, Prabhu NS, El-Deiry WS. University of Pennsylvania Comprehensive Cancer Center, Howard Hughes Medical Institute, Department of Medicine and Genetics, University of Pennsylvania School of Medicine, Philadelphia 19104, USA. Growth arrest and differentiation of leukemic cells by phorbol 12-myristate 13-acetate (PMA) is accompanied by p53-independent activation of p21WAF1/CIP1 and c-myc down-regulation. We show that despite p21 induction in 7 of 12 human cancer cell lines treated with PMA, growth inhibition was observed only in two cell lines (SKBr3 breast and LNCaP prostate cancer cells). Treatment of SKBr3 and LNCaP cells with PMA was followed by Raf-1 hyperphosphorylation, p21 induction, Rb hypophosphorylation, c-myc down-regulation and growth inhibition. The 10 remaining PMA-resistant cell lines were comprised of 5 that failed to induce p21 and 5 that induced p21 but had defects in steps putatively downstream of this (Rb hypophosphorylation and c-myc down-regulation). Exogenous expression and subsequent failure to down-regulate c-myc protein expression in SKBr3 and LNCaP cells was correlated with acquisition of resistance to the growth inhibitory effect of PMA. Exogenous p21 expression down-regulated c-myc protein in PMA-sensitive cancer cells. Our findings suggest that induction of p21 and down-regulation of c-myc may be necessary steps in a PMA-induced growth-inhibitory pathway in cancer cells. PMID: 9000576 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 783: Cancer Treat Res. 1997;91:31-50. Molecular genetics of soft tissue sarcomas. Cooper CS, Cornes P. Molecular Carcinogenesis Section, Haddow Laboratories, Sutton, Surrey, United Kingdom. Publication Types: Review Review, Tutorial PMID: 9286487 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 784: Vitam Horm. 1997;53:1-25. Cell cycle checkpoints and apoptosis: potential for improving radiation therapy. Muschel RJ, McKenna WG, Bernhard EJ. Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia 19104, USA. Publication Types: Review PMID: 9197176 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 785: Adv Cancer Res. 1997;71:121-64. Functional aspects of apoptosis in hematopoiesis and consequences of failure. McKenna SL, Cotter TG. Department of Biochemistry, University College, Cork, Ireland. Apoptosis is an internally directed, physiological method of cell destruction. Cellular components are dismantled within the confines of an intact cell membrane, and rapid ingestion by phagocytic cells prevents local inflammation. A variety of genes have now been identified as positive or negative regulators of apoptosis. Transfection experiments and studies of gene cooperation in viral transformation suggest that full cellular transformation requires not only the deregulation of proliferation, but also the inhibition of concomitant apoptosis programs. The regulation of apoptosis is fundamental to hematopoietic homeostasis. Stem cell renewal is continuously counterbalanced by apoptosis in functionally inactive or terminally differentiated cells. Extensive cell death in developing lymphocyte populations ensures that only cells recognizing non-self antigens are released into the periphery, and the finite lifespan of terminally differentiated cells enables the extensive cell turnover demanded by functional aspects of the hematopoietic system. The requirement of each hematopoietic sub-population for a specific sub-set of survival factors, provides a flexible mechanism for dictating the cellular composition of the mature population and for controlling population size. Surplus cell production and apoptosis are therefore normal features of hematopoiesis. The consequences of deregulated apoptosis are severe. Excessive apoptosis in lymphocyte populations plays a major role in the pathogenesis of acquired immunodeficiency syndrome (AIDS), whereas ineffective apoptosis has been associated with the development of inflammation, autoimmunity and hematological malignancies. The identification of various genetic abnormalities which influence apoptosis in leukaemic cells (e.g., mutant p53, Bcr-Abl and over-expression of Bcl-2), suggests that the acquisition of an anti-apoptotic lesions is an important event in the multi-step evolution of hematological malignancies. In addition, the nature of some leukaemias particularly the chronic leukemias, in which the leukemic cells are nonproliferative and long lived, suggests that anti-apoptotic lesions are early events in the pathogenesis of these diseases. It is likely that the utilization of mechanisms to evade apoptosis would facilitate disease progression in all leukemias and contribute to the development of multi-drug resistance. A better understanding of apoptosis mechanisms in hematopoietic cells, and their exploitation by leukemic cells should be useful in the development of improved cytotoxic regimes. Publication Types: Review PMID: 9111865 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 786: Surg Today. 1997;27(3):226-33. Expression of wild-type p53 tumor suppressor gene and its possible involvement in the apoptosis of thyroid tumors. Kikuchi S, Hiraide H, Tamakuma S, Yamamoto M. First Department of Surgery, National Defense Medical College, Saitama, Japan. A good prognosis is often achieved in patients who have undergone treatment for human papillary carcinoma of the thyroid. On the assumption that this may be partly attributable to an apoptotic tendency of this special type of tumor, we measured DNA fragmentation, cell death by enzyme-linked immunosorbent assay (ELISA), and the expression of apoptosis-related genes. DNA fragmentation occurred more extensively in malignant tumor cells than in benign thyroid tumors or normal thyroid tissue, as examined by agarose gel electrophoresis and confirmed by the quantitative method using an ELISA kit. Although only expression of the tumor suppressor gene, p53, was increased in the tumor tissue, no expression of other genes, such as Fas, TNF, c-myc, c-fos or bcl-2, was observed in the normal, benign, or malignant tumor tissues, indicating that the roles of these gene functions, if any, were minimal in these tissues. Since p53 is closely related to cellular apoptosis and no point mutation was observed in the transcripts expressed by malignant cells, apoptosis and/or the production of an angiogenesis inhibitor induced by wild-type p53 molecules may be related to the favorable prognosis of patients treated for papillary carcinoma of the thyroid. PMID: 9068103 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 787: Cancer Res. 1997 Jan 1;57(1):176-82. p53 status affects the rate of the onset but not the overall extent of doxorubicin-induced cell death in rat-1 fibroblasts constitutively expressing c-Myc. Han JW, Dionne CA, Kedersha NL, Goldmacher VS. Apoptosis Technology, Inc., Cambridge, Massachusetts 02139-4239, USA. iia-wen-han@immunogen.ccmail.compuserve.com To better understand the effects of p53 on the process of DNA damage-induced cell death, we examined the influence of p53 status on the rate of the onset and the overall extent of cell death induced by doxorubicin. We performed this study with Rat-1 fibroblasts, with Rat-1/myc cells which constitutively express c-Myc, and with Rat-1/myc/p53His175 cells derived from Rat-1/myc cells, which, in addition, express the full-length dominant-negative p53His175 mutant gene. The p53His175 mutant suppresses the transactivation function of endogenous p53 in these cells. In contrast to the parental Rat-1 cells, which exhibited only low levels of apoptosis within the first 24 h of treatment with 0.1 to 1 microM doxorubicin, similarly treated Rat-1/myc cells underwent massive and rapid apoptosis. Introduction of p53His175 into Rat-1/myc cells reversed this effect, indicating that Myc-accelerated doxorubicin-induced apoptosis requires functional p53. However, when the overall extent of cell death was measured using clonogenic assays, we found that greater than 90% of cells did not survive upon a 24-h pretreatment with doxorubicin at a concentration as low as 0.1 microM. Moreover, the effect of doxorubicin on all three cell lines was similar, irrespective of their p53 or c-Myc status. Taken together, our experiments indicate that: (a) constitutive expression of c-Myc accelerates the onset of doxorubicin-induced apoptosis in Rat-1 fibroblasts; (b) wild-type p53 function is necessary for this acceleration; and (c) neither overexpression of c-Myc nor the p53 status influences the overall extent of doxorubicin-induced cell death. PMID: 8988061 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 788: Virology. 1996 Dec 15;226(2):176-82. Suppression of apoptotic cell death by hepatitis C virus core protein. Ray RB, Meyer K, Ray R. Division of Infectious Diseases and Immunology, Saint Louis University, Missouri 63110, USA. We have previously demonstrated the role of hepatitis C virus (HCV) core protein in the transcriptional regulation of cellular and unrelated viral promoters. Furthermore, the core protein in cooperation with H-ras oncogene transforms primary rat embryo fibroblast cells to the tumorigenic phenotype. In the present study, the functional role of HCV core protein was investigated to determine its potential to inhibit the onset of apoptotic cell death. Expression of HCV core protein inhibited cisplatin mediated apoptosis in human cervical epithelial cells, and apoptosis induced by the overexpression of c-myc in Chinese hamster ovarian cells. Results from these studies suggest that the core protein may have a biological implication in the pathogenesis of HCV infection. PMID: 8955036 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 789: Eur J Cancer Prev. 1996 Dec;5(6):497-503. Detection of sequential genetic alterations relevant for breast cancer development. Niederacher D, Schnurch HG, An HX, Ellenberger I, Dall P, van Roeyen CR, Kuppers V, Beckmann MW. Department of Gynaecology and Obstetrics, Heinrich-Heine-Universitat, Dusseldorf, Germany. Breast cancer emerges as a multistep process with transformation of normal cells via steps of hyperplasia, premalignant change and in situ carcinoma. Cytogenetic and molecular genetic analyses of breast cancer samples indicate that tumour development involves the accumulation of various genetic alterations, including amplification of oncogenes and mutation or loss of tumour suppressor genes. Microdissection of histological sections is needed to correlate the specific histological change and the genetic alteration. For detection of oncogene amplification quantitative differential polymerase chain reaction (PCR) can be used. For assessment of loss of heterozygosity PCR-based microsatellite polymorphisms detecting differences in short tandem repeat sequences are much more informative than standard two-allele restriction fragment length polymorphism markers. Still, the direct correlation of the genetic alterations to specific histological findings is the key to reveal insight into tumour biology and thereby gain prognostic information for the individual breast cancer patient. PMID: 9061283 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 790: Carcinogenesis. 1996 Dec;17(12):2711-7. Changes in methyl-sensitive restriction sites of liver DNA from hamsters chronically exposed to hydrazine sulfate. Zheng H, Shank RC. Department of Community and Environmental Medicine, University of California, Irvine 92697-1825, USA. Hydrazine sulfate is a genotoxic hepatocarcinogen for the hamster. A study was conducted to follow changes in DNA maintenance methylation in selected genes in liver DNA during the 21-month induction of liver adenomas and hepatocellular carcinomas by demonstrating changes in restriction fragment length polymorphism. Male Syrian golden hamsters were exposed to hydrazine sulfate in the drinking water at three concentrations (170, 340 and 510 mg/l) shown previously to result in a dose-dependent induction of liver tumors. Liver DNA from animals exposed to the high concentration for 6, 12, 16, 20 and 21 months and animals exposed to the low or mid concentration for 21 months was digested with EcoRI, MspI, HindIII or BamHI, or a combination of one of these endonucleases and a methyl-sensitive restriction enzyme, HpaII or HhaI. The DNA digests were subjected to Southern analysis using a c-DNA probe for one of the following genes: DNA methyltransferase (DMT), c-Ha-ras, c-jun, c-fos, and c-myc proto-oncogenes, p53 tumor suppressor gene or gamma-glutamyltranspeptidase. Alteration in DNA restriction by methyl-sensitive endonucleases was detected in four (DMT, c-Ha-ras, p53 and c-jun) of the seven genes examined and as early as 6 months in animals exposed to the highest concentration of hydrazine sulfate; alteration of recognition sites in c-Ha-ras was also detected in DNA from animals exposed for 21 months to the intermediate concentration of hydrazine sulfate. Early changes in recognition sites, presumed to indicate altered methylation status of DNA cytosine and/or guanine mutations, were seen using c-DNA probes for DMT, c-Ha-ras and c-jun; in the p53 tumor suppressor gene alteration of such sites was a late event relevant to appearance of liver adenomas and hepatocellular carcinomas. Evidence for hypomethylation in the p53 and c-jun genes and hypermethylation of the c-Ha-ras and DMT genes is provided. This study supports the induction of site-specific hypomethylation and hypermethylation during the course of hydrazine carcinogenesis. PMID: 9006110 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 791: Int J Hematol. 1996 Dec;65(1):41-8. p53-independent induction of p21 (WAF1/CIP1) during differentiation of HL-60 cells by tumor necrosis factor alpha. Yoshida K, Murohashi I, Hirashima K. First Department of Internal Medicine, Saitama Medical School, Japan. We demonstrated that tumor necrosis factor-alpha (TNF-alpha) rapidly and markedly enhances p21 gene and protein expression prior to monocytic differentiation and apoptosis in p53-null HL-60 cells. TNF-alpha induced early small and delayed large peaks of apoptosis at 6 and 48 h of incubation, respectively. At 24 h of incubation, apparent monocytic differentiation of the cells was noted. Down-regulation of c-myc and c-myb and G0/G1 arrest were observed at 6-12 and 36 h, respectively. Actinomycin D markedly inhibited TNF-alpha-induced p21 mRNA expression, suggesting that the p21 gene is induced at the transcriptional level. We confirmed that TNF-alpha induces p53-independent apoptosis in HL-60 cells, which accompanies monocytic differentiation. PMID: 8990624 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 792: Neurol Res. 1996 Dec;18(6):559-63. Up-regulation of c-myc gene expression following focal ischemia in the rat brain. Nakagomi T, Asai A, Kanemitsu H, Narita K, Kuchino Y, Tamura A, Kirino T. Department of Neurosurgery, Teikyo University School of Medicine, Tokyo, Japan. Changes in gene expression including that of c-fos occur following cerebral ischemia. Proto-oncogenes c-myc and s-myc and oncosuppressor gene p53 are known to induce apoptosis in some types of cells, whereas proto-oncogene bcl-2 inhibits apoptosis. Possible induction of mRNAs for c-myc, N-myc, s-myc, c-fos, p53 and bcl-2 was examined following focal ischemia in the rat anterior cortex, hippocampus, thalamus and cerebellum by Northern blot analysis. Animals were decapitated 1, 2, 6, 12, and 24 hours following the left middle cerebral artery (MCA) occlusion. In sham-operated control rats, the mRNAs for c-myc, N-myc, c-fos and p53 were present in the anterior cortex, hippocampus, thalamus on both sides, and in the cerebellum, whereas those for s-myc and bcl-2 were not. The c-myc gene expression was rapidly and markedly induced by the MCA occlusion in the ipsilateral anterior cortex, hippocampus and thalamus in a time-dependent manner. In these regions, the c-fos gene expression was also induced as early as 1 hour after the MCA occlusion. The p-53 mRNA was induced in the ipsilateral hippocampus at 24 hours after MCA occlusion. In contrast, mRNAs for N-myc, s-myc and bcl-2 were not induced following MCA occlusion. These results indicate a possibility that high-level expression of the c-myc gene may be involved in the ischemic cellular events including apoptosis. PMID: 8985958 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 793: Eur J Immunol. 1996 Dec;26(12):3119-26. Modulation of Apo-1/Fas (CD95)-induced programmed cell death in myeloma cells by interferon-alpha 2. Egle A, Villunger A, Kos M, Bock G, Gruber J, Auer B, Greil R. Laboratory of Molecular Cytology, Department of Internal Medicine, Innsbruck University Hospital, Austria. The Apo-1/Fas (CD95) antigen is known to be involved in the process of T cell-mediated target cell killing and has recently been shown to be expressed on myeloma cell lines and native malignant plasma cells. Several cytokines have been reported to interfere with spontaneous and even Apo-1/Fas-induced apoptosis, but no attempt has been made yet to investigate these interactions and the possible underlying mechanisms in myeloma cells. Since in myeloma patients Interferon (IFN)-alpha2 displays a profound therapeutic effect in vivo, which is usually attributed to its growth inhibitory and/or immunomodulatory capacity, we set out to study the potential interference of IFN-alpha2 with Apo-1/Fas-induced apoptosis. Contrary to expectations, IFN-alpha2 reduced the degree of apoptosis caused by the treatment of five Apo-1/Fas-sensitive myeloma cell lines with a Fas monoclonal antibody (mAb). Simultaneous application of IFN-alpha2 and Fas mAb was superior to the prolonged (i.e. >8 h) preincubation with the cytokine as far as inhibition of Apo-1/Fas-induced apoptosis was concerned. This effect of IFN-alpha2 was neither explained by a down-regulation of the Apo-1/Fas receptor nor caused by modulation of the expression levels of c-myc, bcl-2-, bcl-xL, bax- or p53 genes. IFN-alpha2 did not alter the Apo-1/Fas-induced activity of Mitogen-activated protein kinase (MAPK) 1 and did not inhibit the Apo-1/Fas-mediated proteolytic cleavage of ADP-ribosyltransferase, a substrate of Interleukin-beta1 converting enzyme (ICE) and homologues. However, activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) mimicked the effects of IFN-alpha2. Furthermore, the bis-indolylmaleimide GF 109203X, a specific inhibitor of PKC, inhibited the effect of PMA as well as that of IFN-alpha2 on Apo-1/Fas-induced apoptosis. These results point to a PKC-dependent mechanism of transient interaction between the intracellular signaling along the IFN-alpha2 and the Apo-1/Fas pathway (downstream of MAPK signaling as well as of ICE homologues), which becomes exhausted by prolonged stimulation with the cytokine. According to our data IFN-alpha2, applied continuously and in high doses resembling the therapeutic situation in vivo, inhibits myeloma growth. However, based on the observed inhibitory effect of IFN-alpha2 on Apo-1/Fas-induced apoptosis, a partial inhibition of the natural immune surveillance on myeloma cells by endogenous IFN-alpha2 present in the bone marrow microenvironment of this malignancy should be investigated. PMID: 8977313 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 794: Mol Endocrinol. 1996 Dec;10(12):1688-96. Subtype-selective induction of wild-type p53 and apoptosis, but not cell cycle arrest, by human somatostatin receptor 3. Sharma K, Patel YC, Srikant CB. Fraser Laboratories for Diabetes Research McGill University and Royal Victoria Hospital Montreal, Quebec, Canada. Somatostatin (SST) exerts direct antiproliferative effects in tumor cells, triggering either growth arrest or apoptosis. The cellular actions of SST are transduced through a family of five distinct somatostatin receptor subtypes (SSTR1-5). Whereas growth inhibition has been reported to follow stimulation of protein tyrosine phosphatase via SSTR2 or inhibition of Ca2+ channels via SSTR5 in heterologous expression systems, the subtype selectivity for signaling apoptosis has not been investigated. The tumor suppressor protein p53 and the protooncogene product c-Myc regulate cell cycle progression (growth factors present) or apoptosis (growth factors absent). The p53-induced G1 arrest requires induction of p21, an inhibitor of cyclin-dependent kinases, whereas apoptosis requires induction of Bax. c-Myc is capable of abrogating p53-induced G1 arrest by interfering with the inhibitory action of p21 on cyclin-dependent kinases. We have, therefore, investigated the regulation of p53, p21, c-Myc, and Bax and cellular apoptosis in relation to cell cycle progression in CHO-K1 cells stably expressing individual human SSTR1-5. We demonstrate that apoptosis is signaled uniquely through human SSTR3 and is associated with dephosphorylation-dependent conformational change in wild-type (wt) p53 as well as induction of Bax. The induction of wt p53 occurs rapidly and precedes the onset of apoptosis. We show that the increase in wt p53 is not associated with the induction of p21 or c-Myc when octreotide-induced apoptosis becomes evident, suggesting that such apoptosis does not require G1 arrest and is not c-Myc dependent. These findings provide the first evidence for hormonal induction of wt p53-associated apoptosis via G protein-coupled receptor in a subtype-selective manner. PMID: 8961277 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 795: J Neurosci Res. 1996 Dec 1;46(5):540-50. 1,25-Dihydroxyvitamin D3 induces programmed cell death in a rat glioma cell line. Baudet C, Chevalier G, Chassevent A, Canova C, Filmon R, Larra F, Brachet P, Wion D. INSERM U 298, Centre Hospitalier Universitaire, Angers, France. 1,25-Dihydroxyvitamin D3 (1,25(OH)2D3), a seco-steroid hormone with potential antitumoral activities, has been recently reported to exert cytotoxic effects on C6 glioma cells. However, the molecular mechanisms which trigger this cell death remain unknown. We show here that this 1,25(OH)2D3-induced cell death is dependent upon protein synthesis and is accompanied by the expression of c-myc, p53, and gadd45 genes. Two other genes, coding for interleukin-6 and vaso-endothelial growth factor, are also upregulated after addition of 1,25(OH)2D3. This programmed cell death can be suppressed when cells are treated with forskolin, a drug which increases intracellular cAMP concentration, or with genistein, an inhibitor of tyrosine protein kinases. However, in spite of the demonstration of fragmented DNA in 1,25(OH)2D3-treated cells, the C6.9 cells used in this study do not show the classical morphological features of apoptosis. These results provide the first evidence for the existence of a programmed cell death triggered by 1,25(OH)2D3 in glioma cells and may provide a basis for the development of new therapeutic strategies. In addition, these data also suggest that the treatment of C6.9 cells with 1,25(OH)2D3 may be a useful model to study the molecular mechanisms involved in the programmed cell death of a cell of glial origin. PMID: 8951666 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 796: Gynecol Oncol. 1996 Dec;63(3):337-44. A study of biomarkers in cervical carcinoma and clinical correlation of the novel biomarker MN. Brewer CA, Liao SY, Wilczynski SP, Pastorekova S, Pastorek J, Zavada J, Kurosaki T, Manetta A, Berman ML, DiSaia PJ, Stanbridge EJ. Department of Obstetrics and Gynecology, UCI Medical Center, University of California, Irvine, Orange 92613-14091, USA. The MN protein is a newly described biomarker found to be overexpressed in most cervical carcinomas. This study was an effort to evaluate the prognostic importance of tumor MN expression, HPV status, and the presence of other biomarkers in cervical cancers. Tumor DNA and protein for study were extracted from archived frozen tissue. Tumor tissues and controls were evaluated by Western blot analysis for MN, intestinal alkaline phosphatase (IAP), c-myc, and p53 protein overexpression. Immunohistochemistry was performed for MN quantification and the study of expression patterns in histologic subtypes of cervical cancer. HPV data were obtained by PCR amplification of extracted DNA using consensus and type-specific primers. Clinical data were obtained from the patients' records and from the cancer registry. Clinical and molecular data were correlated by chi2, Fisher's exact test, and logistic regression. The results demonstrate that IAP is not overexpressed in clinical specimens of cervical carcinoma, although in somatic cell hybrid experiments, overexpression of IAP correlates with the malignant state. None of 47 tumors, including those which were HPV negative, overexpressed p53. c-myc protein overexpression occurred in 11 of 52 tumors, most of which contained HPV 16, but this was not significantly different from the tumors as a whole. There was no apparent association between MN protein expression and the overexpression of c-myc protein. MN was overexpressed in all cancers and quantitatively varied with the histologic subtype. Specifically, lower expression of MN correlated with adenosquamous and less-differentiated histology (P < 0.01 for grade 3 tumors). Low expression of MN protein also correlated with HPV negativity (P < 0.05). In stage IB and IIA cancers, low expression of MN was associated with deeper cervical stromal invasion (P < 0.03). Further, low expression of MN correlated with lymph node metastases in small (<3.5 cm) IB and IIA cervical cancers (P < 0.04). These data suggest that MN is emerging as a potentially important new biomarker for cervical carcinoma. The overexpression commonly seen in cervical cancer is possibly associated with loss of a critical tumor suppressor gene located on chromosome 11. Low expression of MN antigen appears to correlate with several adverse prognostic features and further prospective study is warranted. PMID: 8946869 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 797: Int J Cancer. 1996 Nov 15;68(4):514-9. Establishment, characterization and drug sensitivity of four new human soft tissue sarcoma cell lines. Li WW, Cordon-Cardo C, Chen Q, Jhanwar SC, Bertino JR. Laboratory of Molecular Pharmacology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA. Four new cell lines were established from patients with soft tissue sarcomas. Drug sensitivity as well as genotypic characterization, which may be related to drug sensitivity in these cell lines, was determined. Karyotype, H-ras, c-myc and mutant p53 gene expression, Rb, G1- and S-phase cyclins, E2F and major cyclin/CDK inhibitors such as p16 and p21 and p-glycoprotein were analyzed using cytogenetic, Northern blot and immunological methods. Drug sensitivity was determined using growth inhibition tests. These cell lines differed in their morphology and growth rates, forming colonies in soft agar with a cloning efficiency of 4.3-13.4%, and 3 of the 4 cell lines grew in nude mice. Cytogenetic analysis of cell lines revealed highly aneuploid karyotypes. Deletion and/or translocation of chromosome 17 was seen in HS-16, HS-18 and HS-30 cells, and both copies of chromosome 13 were lost or re-arranged in the HS-18 cell line. Mutant p53 protein was present in all 4 cell lines. HS-18 cells showed no expression of the Rb protein and high levels of expression of E2F, cyclin A, cyclin E and CDK2. HS-16 expressed a higher level of cyclin D than the other 3 cell lines. p21WAF1 expression was seen in all cell lines, but p16ink4 was expressed only in HS-30 and HS-42 cell lines. These cell lines were sensitive to taxol and relatively resistant to methotrexate, vinblastine and 5-fluorouracil when compared with the fibrosarcoma cell line HT-1080. These new cell lines should provide a useful model for the study of soft tissue sarcomas and for evaluating new drugs or treatments. PMID: 8945624 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 798: Anticancer Res. 1996 Nov-Dec;16(6B):3705-8. 4,9-diazapyrenium dications induce apoptosis in human tumor cells. Steiner-Biocic I, Glavas-Obrovac L, Karner I, Piantanida I, Zinic M, Pavelic K, Pavelic J. Department of Biochemistry, Faculty of Food Technology, University of Osijek, Croatia. We investigated the antiproliferative effects of two planar 4,9-diazapyrenium hydrogenasulphates against human malignant MiaPaCa 2 (pancreatic carcinoma), Hep 2 (laryngeal carcinoma) and human normal fibroblasts (WI 38) cell lines. The tested compounds were very potent in inhibiting the growth of the treated cell lines. Treatment with molar concentrations of the substances (10(-4)-10(-7) M) caused growth inhibition by more than 50%. The morphological changes of treated cells were also observed. Cells became smaller, with condensed chromatin and fragmented nuclei, the characteristics of dying cells. The identification of DNA-fragmentation and the appearance of chromatin aggregation leads us to assume the tested substances induced apoptosis of the investigated tumor cell lines. PMID: 9042244 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 799: Anticancer Res. 1996 Nov-Dec;16(6B):3659-64. The effect of etoposide (VP-16) on mouse L fibroblasts: modulation of stress response, growth and apoptosis genes. Sacchi CM, Schiaffonati L. Dipartimento di Medicina ed Oncologia Sperimentale, Universita degli Studi, Torino, Italy. Molecular events were studied in mouse L cells treated with etoposide (VP-16) a drug widely used in cancer therapy. Modulation of the expression of stress response genes belonging to the hsp70 family (hsp70, hsc73, grp78), growth- and cycle-related genes (c-myc, c-fos, c-jun, histone H3) and apoptosis-related genes (p53, TRPM-2, tTG) was monitored at different time points in the cells that remained adherent to the substrate up to 96 hours after exposure to VP-16. The steady state level of mRNA was determined by Northern blot analysis and hybridization with specific probes, and the relative rate of gene transcription was monitored by run on transcription with isolated nuclei. Our results indicate that protracted VP-16 treatment of 1. cells induces, within 24 hours, the arrest of DNA synthesis, repression of growth-related genes and transient induction of the tTG gene. Altogether these molecular events may contribute to the cytotoxic effect of VP-16. However in cells surviving a longer exposure to the drug, the expression of growth-related genes resumes, even if a blockade in DNA replication persists, and expression of the grp78 gene significantly increases. These data suggest that under continuous treatment with VP-16 a fraction of L cells showing increased resistance to the drug may emerge. PMID: 9042238 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 800: Anticancer Res. 1996 Nov-Dec;16(6B):3537-41. Genomic effects of tamoxifen. Kellen JA. Sunnybrook Health Sciences Centre, Department of Clinical Biochemistry, University of Toronto, Ontario, Canada. Tamoxifen exerts a variety of genomic effects which explains, in part, its efficacy in both hormone-responsive and independent tumours. The above quotation expresses this in a timeless and elegant way: our understanding of antiestrogen action has been narrowly fettered by the simplistic interpretation of this drug as an antihormone. The regulatory and controlling influence of Tamoxifen on numerous genes involved in apoptosis (p53, Bcl 2, c-myc, erb-B2 and others) will be discussed in this review. Publication Types: Review Review, Tutorial PMID: 9042218 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 801: Anticancer Res. 1996 Nov-Dec;16(6B):3483-9. Deoxyadenosine-resistant mouse leukemia L1210 cell lines with alterations in early response genes and p53. Cory JG, He AW, Cory AH. Department of Biochemistry, East Carolina University School of Medicine, Greenville, NC 27858, USA. L1210 cell lines selected for resistance to deoxyadenosine exhibit altered steady-state levels of the mRNA for the early response genes and p53. In the deoxyadenosine-resistant cell lines (Y8 and ED2), the levels of the mRNAs for p53 and c-jun were markedly decreased while the steady-state levels for mRNAs for c-myc, c-fos and jun B were elevated in the Y-8 and ED2 cell lines. The levels of the mRNAs for PCNA and c-myb were the same in the wild type and mutant cell lines. The levels of the mRNAs for krox-24 were extremely low in the wild type and mutant cell lines. Cycloheximide (CHX) treatment of the cells resulted in the increase in the mRNA levels for c-jun, jun B, krox 24 and p53 in the Y-8 and ED2 cell lines. The time courses and the extents of the increases in the mRNA levels following CHX treatment were not the same for all of these mRNAs. The level of p53 RNA increased with no lag following CHX treatment while the levels of the mRNAs for c-myc, c-jun and krox-24 increased after a one-hour lag period. The level of the mRNA for p53 and c-myc increased 20- and 7-fold, respectively while the mRNA level for knox-24 increased 80-fold following CHX treatment. The Y8 and ED2 cell lines that lack steady-state levels of p53 show decreased sensitivity to cisplatin and increased frequency of gene amplification as measured by PALA resistance in a manner similar to other cell lines lacking p53. On the other hand, the ED2 and Y8 cell lines do not show a G1-block in response to PALA treatment. The cell lines appear to offer an experimental system in which to study the interactions between/among these early response genes and the p53-dependent and independent pathways. PMID: 9042210 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 802: Virchows Arch. 1996 Nov;429(4-5):221-7. DNA ploidy and MYC DNA amplification in ovarian carcinomas. Correlation with p53 and bcl-2 expression, proliferative activity and prognosis. Diebold J, Suchy B, Baretton GB, Blasenbreu S, Meier W, Schmidt M, Rabes H, Lohrs U. Pathological Institute, Ludwig Maximilians University, Munchen, Germany. There is increasing evidence that DNA ploidy is a prognostic factor in ovarian carcinomas, but it is uncertain whether MYC DNA amplification is an epiphenomenon of DNA nondiploidy or a distinct biological change with an impact on the clinical course of the disease. To clarify these issues we analysed DNA ploidy by flow and image cytometry and MYC copy number by polymerase chain reaction in archival material from ovarian carcinomas with known follow up. The results were compared with proliferative activity (Ki67 index) and p53 and bcl-2 expression. DNA cytometry revealed nondiploidy in 84 of 144 cases (58.3%). Nondiploidy was statistically significantly correlated with histological tumour type, histological grade, Ki67 index > 10%, FIGO stage, presence of residual tumour after debulking surgery and adverse postoperative outcome. Furthermore, DNA nondiploidy was associated with p53 accumulation. We found that 84.9% of the p53-positive cases were nondiploid. This points to the paramount importance of wild type p53 for the maintenance of genome integrity in this tumour type. MYC DNA amplification was seen in 33.8% (26/77 cases) of ovarian carcinoma. There was no correlation between MYC DNA amplification and histological tumour type, histological grade, FIGO stage, DNA ploidy, proliferative activity or prognosis. However, when p53 and bcl-2 expression was taken into account, a statistically significant correlation between gene alteration or expression patterns and histological tumour type was revealed. The group of mucinous carcinomas demonstrated both MYC DNA amplification and strong bcl-2 expression in 50% and contained the largest fraction of cases without aberration (37.5%). Endometrioid carcinomas were characterized by strong bcl-2 expression in 85%, whereas serous and undifferentiated carcinomas predominantly exhibited p53 alterations, frequently accompanied by bcl-2 overexpression or MYC DNA amplification. Thus, in interaction with other genes MYC DNA amplification may play a role in the determination of the varying differentiation patterns of ovarian carcinomas. PMID: 8972757 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 803: Ann Surg Oncol. 1996 Nov;3(6):574-9. Higher expression of oncoproteins c-myc, c-erb B-2/neu, PCNA, and p53 in metastasizing colorectal cancer than in nonmetastasizing tumors. Yang JL, Ow KT, Russell PJ, Ham JM, Crowe PJ. Department of Surgery, Prince of Wales Hospital, University of New South Wales, Sydney, Australia. BACKGROUND: Expression of individual oncogenes may predict outcome in patients with metastatic colorectal cancer (CRC). We studied the oncogene profile in the tumors of patients with CRC and assessed their value as predictors of liver metastases. METHODS: The oncoproteins c-myc, c-erbB-2/neu (c-neu), PCNA and p53, were measured by immunohistochemistry in sections of metastasizing human CRC (n = 34) and their liver secondaries as well as in sections of nonmetastasizing human CRC (n = 25). RESULTS: The metastasizing primary CRC expressed proliferating-cell nuclear antigen (PCNA), c-neu, and c-myc at significantly higher levels than the nonmetastasizing primary cancer, p53 was also overexpressed in the metastatic group compared with the nonmetastasizing CRC, but this difference was not significant. The frequency of expression of all these markers was similar in the metastasizing primary CRC and the liver secondaries from the same patients. There was no correlation between the expression of the individual markers and histological grade, DNA ploidy, and subsequent local recurrence and lung metastasis and survival. However, when both groups were assessed together, positive expression of c-myc was more likely to occur in poorly differentiated tumors, whereas PCNA expression increased with more advanced Dukes stages. CONCLUSION: These results suggest that the overexpression of c-myc, c-neu, PCNA, and p53 may occur in CRC that are likely to metastasis to the liver. PMID: 8915491 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 804: Pathol Int. 1996 Oct;46(10):764-70. Expression of apoptosis, proliferating cell nuclear antigen, and apoptosis-related antigens (bcl-2, c-myc, Fas, Lewis(y) and p53) in human cholangiocarcinomas and hepatocellular carcinomas. Terada T, Nakanuma Y. Second Department of Pathology, Kanazawa University School of Medicine, Japan. In situ expression of apoptosis and its related antigens has rarely been evaluated in human liver tumors. Therefore, investigation using in situ nick end-labeling and immunohistochemical methods of the in situ expression of apoptosis, proliferating cells, and apoptosis-related antigens in 7 normal livers, 20 cholangiocarcinomas (CC) and 17 hepatocellular carcinomas (HCC) was done. Apoptotic cells as determined by the nick end-labeling method and proliferating cell nuclear antigen-positive cells were present in all specimens, and the percentage of them was significantly higher in CC than in HCC. Bcl-2 protein was present only in one CC and one HCC, but was occasionally noted in bile ducts in non-cancerous livers. C-myc and Fas antigens were not found in any of the cases. Lewisy antigen was expressed in 8 CC, but was absent in the other cases although bile ducts in non-cancerous livers frequently expressed Lewisy. p53 protein was present in 8 CC, but was absent in the other cases. Serial section observations showed that apoptotic cancer cells were consistently negative for proliferating cell nuclear antigen; bcl-2-positive cells did not show apoptosis; p53-positive cancer cells showed apoptosis. Some Lewisy-positive cancer cells showed apoptosis, while others did not. These data suggest that apoptosis and cell proliferation are involved in CC and HCC, and their degree is more severe in CC than in HCC. p53 protein (stimulative) may regulate apoptosis in some cases, whereas c-myc, Fas and Lewisy are not related to apoptosis in CC and HCC in vivo. Many other factors may regulate apoptosis in CC and HCC in vivo. PMID: 8916146 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 805: Cancer Lett. 1996 Oct 1;107(1):19-28. Phenotypic and genotypic analysis of rat liver epithelial cells infected with retroviral shuttle vectors. Dees C, Travis C. Risk Analysis Section, Oak Ridge National Laboratory, TN 37831-6109, USA. Rat liver epithelial cells (RLE) are suspected to be pluripotent hepatic stem cells that give rise to a diverse variety of liver tumors. The molecular events responsible for transformation of these cells and the diversity of the tumor phenotypes remains to be fully elucidated. We examined the genotype and phenotype of RLE cells infected with retroviral shuttle vectors carrying a neomycin resistance (neor) Ha-ras or a lacZ gene. WBneoIII, WBrasIII and WBlacZ cell lines were examined for evidence of a transformed phenotype by comparing their behavior with the parental strain (WB-344) and with WBneo-C-II and WBrasII cells. Confluent cultures of WBneo-C-II and WBrasII cells were found to contain significantly higher numbers of total cells than the other cell lines. The growth rate of WBneo-C-II and WBrasII cells were faster than that of the parental cell line. Addition of epidermal growth factor (EGF) to the medium was found to stimulate the growth rate of WBneo-C-II cells and to induce anchorage independent growth (AIG). No cell line produced tumors in nude mice (nu/nu) except WBrasII cells. Radioimmunoprecipitation studies and sequencing of the p53 exons 5-8 indicate WBneo-C-II, and WBrasII cells produce a mutant p53. Northern blot analysis showed an increased expression of c-myc mRNA in WBneo-C-II and WBrasII cells. These results demonstrate that alterations in critical growth and differentiation controlling genes have occurred in WBrasII cells which may, independent of or in conjunction with ras insertion, cause the transformed phenotype. PMID: 8913262 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 806: J Cell Biochem. 1996 Oct;63(1):37-50. Oncogene alterations in primary, recurrent, and metastatic human bone tumors. Pompetti F, Rizzo P, Simon RM, Freidlin B, Mew DJ, Pass HI, Picci P, Levine AS, Carbone M. Department of Pathology, University of Chicago, Illinois 60637, USA. We investigated the structure and the expression of various oncogenes in three of the most common human bone tumors-osteosarcoma (36 samples from 34 patients), giant cell tumor (10 patients), and chondrosarcoma (18 patients)-in an attempt to identify the genetic alterations associated with these malignancies. Alterations of RB and p53 were detected only in osteosarcomas. Alterations of c-myc, N-myc, and c-fos were detected in osteosarcomas and giant cell tumors. Ras alterations (H-ras, Ki-ras, N-ras) were rare. Chondrosarcomas did not contain any detectable genetic alterations. Our results suggest that alterations of c-myc, N-myc, and c-fos oncogenes occur in osteosarcomas, in addition to those previously described for the tumor suppressor genes RB and p53. Moreover, statistical analyses indicate that c-fos alterations occur more frequently in osteosarcoma patients with recurrent or metastatic disease. Publication Types: Review Review, Tutorial PMID: 8891902 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 807: J Clin Endocrinol Metab. 1996 Oct;81(10):3547-52. Establishment of anaplastic thyroid carcinoma cell lines useful for analysis of chemosensitivity and carcinogenesis. Asakawa H, Kobayashi T, Komoike Y, Yanagawa T, Takahashi M, Wakasugi E, Maruyama H, Tamaki Y, Matsuzawa Y, Monden M. Second Department of Internal Medicine, Osaka University Medical School, Japan. Anaplastic thyroid carcinoma (ATC) is usually associated with a poor prognosis, with most patients dying within a few months. The mechanism of its carcinogenesis is unclear, and its rapid growth and spread often prevent effective surgical therapy. Thus, chemotherapy is necessary. However, ATC is often resistant to anticancer drugs. Therefore, prediction of chemosensitivity is important in selecting appropriate treatment. In this study, after the establishment of three cell lines (K119, KOA2, and IAA) from patients with ATC, we analyzed them for abnormalities in certain oncogenes (myc, ras, ret, and c-erbB2) and the p53 tumor suppressor gene. Only one of three cell lines (KOA2) had a N-ras mutation [codon 61 CAA(Gln)-->CGA(Arg)] and a p53 gene mutation [exon 6 codon 192 Caa(Gln)-->TAG(stop)]. We also investigated their in vitro drug sensitivity and compared it with clinical chemosensitivity, retrospectively. In vitro drug sensitivity was determined using an adhesive tumor cell culture system. Only the K119 cells were sensitive to adriamycin and cisplatin in vitro. The other two were resistant to them in vitro. These results paralleled the clinical responses. We also evaluated the in vitro drug sensitivity of a poorly differentiated thyroid carcinoma cell line (SMP) and papillary thyroid carcinoma cell lines (NPA). None of the five cell lines expressed the multidrug resistance gene (mdr-1). In conclusion, we established ATC cell lines that are suitable models for characterizing the nature of multidrug resistance and carcinogenesis. PMID: 8855799 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 808: Cancer Res. 1996 Oct 1;56(19):4366-9. Suppression of malignancy by the 3' untranslated regions of ribonucleotide reductase R1 and R2 messenger RNAs. Fan H, Villegas C, Huang A, Wright JA. Manitoba Institute of Cell Biology and The University of Manitoba, Winnipeg, Canada. Mammalian ribonucleotide reductase is rate limiting for the synthesis of DNA. The active enzyme is composed of two dissimilar components called R1 and R2, encoded by different genes. The 3' untranslated regions (3' UTRs) of R1 and R2 messages contain sequences that are important in regulating gene expression through changes in message stability. We have constructed expression plasmids containing the R1 or R2 mRNA 3' UTRs, and we show that transfection of these plasmids into highly malignant mouse 10 T1/2 cells significantly suppresses the tumorigenic properties of these cells in syngeneic mice when compared with cells transfected with the same plasmid lacking R1 or R2 3' UTR sequences or when compared with cells transfected with the same plasmid expressing a heterologous sequence as a control. Furthermore, cells expressing the R2 3' UTR exhibit significantly reduced potential to disseminate to the lungs of syngeneic animals in experimental metastasis assays. The tumor-suppressive effects of the mouse R1 and R2 3' UTRs were not confined to mouse cells, because human HeLa cells transfected with expression plasmids containing either RI or R2 3' UTRs were also significantly less tumorigenic in assays using BALB/c nu/nu mice. These studies demonstrate that the untranslated regions of ribonucleotide reductase mRNAs can function as modifiers of tumor cell development and for the more complex process of tumor dissemination. We propose that these malignancy-suppressive effects are mediated through RNA interactions with cellular components involved in growth regulation through mechanisms of posttranscriptional control of gene expression. In addition, these observations emphasize the enormous potential of untranslated RNA to act directly as modifiers of biological characteristics relevant to mechanisms of malignancy. PMID: 8813126 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 809: Oncogene. 1996 Sep 19;13(6):1153-60. Dysregulation of cellular proliferation and apoptosis mediates human autosomal dominant polycystic kidney disease (ADPKD). Lanoix J, D'Agati V, Szabolcs M, Trudel M. Institut de Recherches Cliniques de Montreal, Faculte de Medicine del'Universite de Montreal, Quebec, Canada. The proto-oncogene c-myc has been implicated in both cellular proliferation and apoptosis, and we have shown that overexpression of c-myc can induce polycystic kidney disease in transgenic mice. To elucidate the molecular and cellular defects underlying cystogenesis, we have investigated the potential roles of cell proliferation and apoptosis as they relate to c-myc and modulators of c-myc function in human autosomal dominant polycystic kidney disease (ADPKD). Renal c-myc expression was consistently elevated, up to 15-fold, in ADPKD. High levels of c-myc expression correlated with 10- to 100-fold increased proliferation index in cystic epithelium. Interestingly, steady-state levels of bcl-2 mRNA were also increased up to 20-fold and Bcl-2 protein was markedly elevated. In contrast, the expression of bax and p53 was virtually unchanged. However, apoptosis was consistently and significantly increased in ADPKD kidneys, unchecked by high levels of Bcl-2. Together with proliferation, apoptosis may thus represent a general mechanism for cyst growth and tissue remodeling. We conclude that both epithelial cell proliferation and apoptosis required for normal kidney homeostasis are deregulated in ADPKD, recapitulating the renal developmental program. Furthermore, abnormal expression of proto-oncogenes regulating these processes is an important mediator of cystogenesis in human ADPKD. PMID: 8808689 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 810: Blood. 1996 Sep 15;88(6):2172-82. Theophylline synergizes with chlorambucil in inducing apoptosis of B-chronic lymphocytic leukemia cells. Mentz F, Mossalayi MD, Ouaaz F, Baudet S, Issaly F, Ktorza S, Semichon M, Binet JL, Merle-Beral H. Department of Hematology, Unite Claude-Bernard C20, Pitie-Salpetriere Hospital, Paris, France. We tested the effects of theophylline, a phosphodiesterase inhibitor inducing intracellular accumulation of cyclic adenosine monophosphate (cAMP), on malignant B cells from 15 patients with B-chronic lymphocytic leukemia (B-CLL). We observed a large increase in apoptotic cell numbers (mean, 90% v 20% in medium alone) in the presence of theophylline (100 micrograms/mL) or chlorambucil (10 mumol/L) after 72 hours of incubation. Maximal apoptosis (90%) was reached after 36 hours when the two drugs were used together at fourfold lower concentrations, indicating a synergistic effect; no effect was observed with normal B cells, suggesting that the combination might have therapeutic interest. Chlorambucil induced intracellular Ca+2 influx, pointing to the involvement of two signaling pathways that might explain its synergy with theophylline through their effects on oncogenes. The expression of bcl-2 protein, a proto-oncogene inhibiting apoptosis, decreased after incubation with the drugs, while c-myc, recently described as having a potent role in apoptosis, was overexpressed. For p53 we observed an overexpression in the presence of chlorambucil or both theophylline-chlorambucil and a decrease after theophylline incubation. Chlorambucil- and theophylline-induced apoptosis was partially inhibited by interleukin-4 (IL-4), which also abrogated the effects on oncogene expression. These results provide insight into the mechanisms underlying B-CLL apoptosis and suggest that the theophylline-chlorambucil combination may be of therapeutic value in this setting. PMID: 8822937 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 811: Oncogene. 1996 Sep 5;13(5):955-61. Apoptosis of NIH3T3 cells overexpressing the Src homology 2 domain protein Shb. Karlsson T, Welsh M. Department of Medical Cell Biology, Uppsala University, Sweden. To understand the role of the Src homology 2 (SH2) domain protein Shb in the signal transduction of tyrosine kinase receptor, NIH3T3 cells were transfected with a DNA construct expressing the Shb cDNA (NIHSHB cells). The NIHSHB cells expressed elevated levels of proteins with the estimated molecular weights of 77, 66 and 55 kDa as determined by immunoblotting. In contrast to the control cells, the NIHSHB cells failed to increase in cell number in the presence of 1% serum. This effect was largely due to apoptosis, since staining of pyknotic nuclei was observed using the terminal transferase labeling method. The NIHSHB cells displayed similar levels of c-myc mRNA and decreased contents of the p53 protein after culture in 1% serum compared with control cells. The addition of platelet-derived growth factor (PDGF-BB) restored the growth of the NIHSHB cells, whereas insulin-like growth factor-1 (IGF-1) failed to affect the proliferation of Shb overexpressing cells in 1% serum. We conclude that Shb overexpression is associated with cell degeneration under certain conditions, and that Shb could transduce apoptotic signals from tyrosine kinase receptors. PMID: 8806685 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 812: Cancer Lett. 1996 Aug 23;106(1):43-9. Molecular analyses of liver tumors in c-myc transgenic mice and c-myc and TGF-alpha double transgenic mice. Ohgaki H, Sanderson ND, Ton P, Thorgeirsson SS. Laboratory of Experimental Carcinogenesis, National Cancer Institute, NIH, Bethesda, MD 20892, USA. It has been demonstrated that co-expression of c-myc and transforming growth factor alpha (TGF-alpha) as transgenes in the mouse liver results in a tremendous acceleration of neoplastic development in this organ as compared to expression of either transgene alone [Murakami, H., et al. (1993) Cancer Res., 53, 1719-1723]. In order to clarify the roles of transgenes and additional other genetic alterations during hepatocarcinogenesis, we analyzed liver tumors developed in albumin/c-myc transgenic mice and albumin/c-myc and MT-1/TGF-alpha double transgenic mice. High expression of TGF-alpha transgene was found in nine of 14 (64%) liver tumors in double transgenic mice, suggesting that TGF-alpha overexpression confers growth advantage during hepatocarcinogenesis. Only one of 14 (7%) liver tumors in double transgenic mice and none of 13 liver tumors in c-myc transgenic mice showed overexpression of insulin-like growth factor II (IGF-II). This result was in contrast to the report by Takagi et al. [Takagi, H., et al. (1992) Cancer Res., 52, 5171-5177] which showed overexpression of IGF-II in 75% of liver tumors in TGF-alpha transgenic mice and suggested that the presence of c-myc transgenes together with TGF-alpha from an early stage of hepatocarcinogenesis may lead to different carcinogenic pathways which are independent of IGF-II overexpression. Expression of c-myc transgene was found in most of the liver tumors, but at lower levels than non-tumorous parts of the liver in c-myc and double transgenic mice. These results suggest that c-myc transgene expression cooperates with TGF-alpha in the early stages of hepatocarcinogenesis but has growth disadvantage in later stages of hepatocarcinogenesis. There was no evidence of mutational activation of the H-ras gene or mutational inactivation of the p53 gene in any liver tumors developed in c-myc or double transgenic mice. PMID: 8827045 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 813: Oncogene. 1996 Aug 1;13(3):609-16. Differential regulation of p53, c-Myc, Bcl-2 and Bax protein expression during apoptosis induced by widely divergent stimuli in human hepatoblastoma cells. Jiang MC, Yang-Yen HF, Lin JK, Yen JJ. Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China. Apoptosis of HepG2 cells triggered by various agents is characterized in an attempt to delineate the common apoptosis signaling pathway in human hepatoma cells. Several hallmarks of apoptosis, including DNA laddering, chromatin condensation and fragmentation, and an apoptosis specific cleavage of 28S and 18S ribosomal RNA were observed after treatment with curcumin. Curcumin treatment however did not alter the expression levels of Bcl-2 and Bax proteins. p53 protein accumulated slowly and decreased abruptly after reaching the maximum. Conversely, c-Myc protein decreased initially and subsequently increased preceding the onset of apoptosis. The accumulation of p53 protein is not due to increased levels of p53 mRNA and does not result in growth arrest. Staurosporine, quinacrine, ultraviolet irradiation, hydrogen peroxide, and cyclohexamide are all capable of triggering apoptosis in HepG2 cells. While most of these agents affect the expression levels of p53 and c-Myc similarly, none of them altered the expression levels of the Bcl-2 and Bax proteins. In conclusion, these data suggest that p53 and c-Myc may play a more important role in the apoptosis signaling pathway in HepG2 cells, than the bcl-2 gene family. PMID: 8760302 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 814: FASEB J. 1996 Aug;10(10):1192-7. Involvement of interleukin-1 beta-converting enzyme in apoptosis of bFGF-deprived murine aortic endothelial cells. Kondo S, Kondo Y, Yin D, Barnett GH, Kaakaji R, Peterson JW, Morimura T, Kubo H, Takeuchi J, Barna BP. Department of Neurosurgery, Cleveland Clinic Foundation, Ohio 44195, USA. Apoptosis (programmed cell death) is an essential physiological process that is genetically regulated and contributes to the balance between cell growth, differentiation, and the maintenance of normal cells. Recent studies show that deprivation of growth factor induces apoptosis in endothelial cells. However, the molecular mechanisms regulating apoptosis remain unclear. In this study, we demonstrate that deprivation of basic fibroblast growth factor (bFGF) increased the expression of interleukin-1 beta-converting enzyme (ICE) protein, and subsequently induced apoptosis in murine aortic endothelial (MAE) cells. In contrast, the proteins of the tumor suppressor p53 and c-myc were undetected during apoptosis. This apoptosis was suppressed by the tetrapeptide ICE inhibitor, Ac-YVAD-CMK. Overexpression of murine ICE, in addition, induced apoptosis in MAE cells using gene transfer techniques. These results strongly suggest that ICE may mediate apoptosis in bFGF-deprived endothelial cells, and the suppression of ICE function could represent a novel approach for the protection of endothelial cells from damages.-Kondo, S., Kondo, Y., Yin, D., Barnett, G. H., Kaakaji, R., Peterson, J. W., Morimura, T., Kubo, H., Takeuchi, J., Barna, B. P. Involvement of interleukin-1 beta converting enzyme in apoptosis of bFGF-deprived murine aortic endothelial cells. PMID: 8751721 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 815: Int J Cancer. 1996 Jul 17;67(2):204-10. Molecular characterization of a novel cancer cell line established from human carcinoma in pleomorphic adenoma (CaPA-4). Fujioka M, Shimada K, Kitazawa S, Maeda S. Second Department of Pathology, Kobe University School of Medicine, Japan. A cultured cell line (CaPA-4), derived from an undifferentiated carcinoma in a pleomorphic adenoma of the submandibular gland, was established through xenografted tumors in nude mice. Geneticin treatment eliminated surrounding mouse fibroblasts and yielded enriched tumor cells at an early stage of cell passage. In vitro, the line grew in a cobblestone pattern, revealing its epithelial origin. Chromosomal analysis by Giemsabanding confirmed its human origin, while electron microscopic examination showed its squamous-cell characteristics. CaPA-4 cells stained positive for the c-myc and Ha-ras antibodies. Molecular analysis showed over-expression of both c-myc and Ha-ras mRNA, with point mutation of p53 at codon 248 and of Ha-ras at codon 61. Amplification and rearrangement of the Ha-ras gene were observed; however, no loss of heterozygosity (LOH) of the p53 gene was detected by Southern blotting. This sequence of cancer-related gene activation may represent the malignant transformation from benign pleomorphic adenoma. This report describes the establishment and molecular characterization of this novel cell line from carcinoma in pleomorphic adenoma exhibiting squamous-cell differentiation. This could represent a useful model for investigating the cause of malignant transformation from human salivary-gland mixed tumors. PMID: 8760589 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 816: Cancer Res. 1996 Jul 15;56(14):3359-65. Transforming growth factor beta1 stimulates contrasting responses in metastatic versus primary mouse prostate cancer-derived cell lines in vitro. Sehgal I, Baley PA, Thompson TC. Urology Research Laboratory, Veterans Affairs Medical Center, Baylor College of Medicine, Houston, Texas 77030, USA. Tumor progression to the stage of metastasis may result in part from the selection of certain primary tumor cell clones which are phenotypically competent for survival, invasion, and growth at secondary sites. Selection for traits such as loss of growth inhibitory responses, acquisition of increased adhesiveness, increased local immunosuppression, and enhanced motility and collagenase activities likely contribute to cancer progression and may be regulated through the action of growth factors. The transforming growth factors (TGF-beta) family of growth factors has often been associated with these traits and tumor progression; therefore, elimination or subversion of TGF-beta-responsive pathways should be considered as a mechanistic framework for metastatic events. In this report, we have compared growth and extracellular matrix responses to TGF-beta in six metastatic and six primary tumor-derived cell lines in a mouse model of prostate cancer. We have found that tumor cell lines derived from focal pulmonary metastasis secreted relatively greater quantities of total TGF-betas, lost most or all TGF-beta1 growth inhibition, but responded to TGF-beta1 through induction of the type IV collagenase matrix metalloproteinase-9, whereas cell lines derived from tumors which proliferated at the primary site retained the growth inhibition but lacked collagenase activity. Synthesis of another extracellular matrix protein, plasminogen activator inhibitor 1, was stimulated by TGF-beta1 in both primary as well as metastatic tumors. These results suggest that acquisition of differential responses to the TGF-beta family could result in phenotypic traits which facilitate tumor metastasis from certain primary site clones. PMID: 8764134 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 817: Int J Cancer. 1996 Jul 3;67(1):106-12. Wild-type p53-induced apoptosis in a Burkitt lymphoma cell line is inhibited by interferon gamma. Sangfelt O, Einhorn S, Bjorklund AC, Wiman KG, Okan I, Grander D. Department of Oncology-Pathology, Karolinska Hospital and Institute, Stockholm, Sweden. The tumor suppressor p53 plays a central role in negative growth control, including growth arrest and apoptosis. Interferons (IFNs) are capable of modulating a variety of cellular responses, including apoptosis. In this study, we have evaluated the influence of gamma- and alpha-interferon (IFN) on wild-type (wt) p53-induced apoptosis using a Burkitt lymphoma cell line, BL41, transfected with a temperature-sensitive p53 construct, gamma-IFN, but not alpha-IFN, was found to protect cells from wt p53-induced apoptosis. The gamma-IFN-dependent protection was due neither to down-regulation of p53, nor to the p53-induced genes, p21 (WAF-1) and bax, nor to up-regulation of bcl-2 or bcl-xL. Expression of the proto-oncogene c-myc, implicated in the control of both proliferation and apoptosis, was not affected by gamma-IFN. We conclude that gamma-IFN can suppress p53-induced apoptosis, and that the cytokine microenvironment may be decisive in the cellular response to wt p53 expression. PMID: 8690509 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 818: In Vivo. 1996 Jul-Aug;10(4):405-9. Response of cultured cells from the epidermis and the buccal mucosa to TGF-beta 1 and comparison to interferon-gamma. Arany I, Tyring SK, Hoskins SL, Brysk H, Chen SH, Selvanayagam P, Rajaraman S, Brysk MM. Department of Microbiology and Immunology, University of Texas Medical Branch, Galvesto 77555, USA. Normal human cells from epidermis and from buccal mucosa were cultured to confluence in three media with graded differentiation potential (at low Ca2+, high Ca2+, and supplemented with serum) and treated with transforming growth factor beta 1 (TGF-beta 1), as had been done previously with interferon-gamma (IFN-gamma). The response of the cells to TGF-beta 1 was monitored in terms of the expression of regulatory genes associated with proliferation and differentiation (cdc2, c-myc, p53) and of genes for structural proteins expressed at varying stages of maturation (keratins K5 and K10, involucrin, flaggrin). For both tissues, the results obtained with both agents were very similar for those genes expressed in the basal cells (cdc2, c-myc, p53, K5), regardless of their function, but diverged for the other genes, which are expressed in the suprabasal cells. Another related contrast is that, although IFN-gamma induced apoptosis in epidermal keratinocytes cultured in the serum containing medium, TGF-beta 1 did not. Thus, the two agents appear to affect the earlier stages of cell differentiation in the same way but to differ at the later stages, particularly in that IFN-gamma pushes maturation further than does TGF-beta 1). PMID: 8839786 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 819: Genes Chromosomes Cancer. 1996 Jul;16(3):170-9. TP53 and MYC gene alterations independently predict poor prognosis in breast cancer patients. Berns EM, Klijn JG, Smid M, van Staveren IL, Look MP, van Putten WL, Foekens JA. Department of Medical Oncology, Dr. Daniel den Hoed Cancer Center, Rotterdam, The Netherlands. Berns@bidh.azr.nl We intended to establish the frequency of exon-specific TP53 gene alterations and the relation to patient and tumor characteristics and clinical outcome of patients with breast cancer. By using polymerase chain reaction-single-strand conformation polymorphism analysis (PCR-SSCP) and sequencing techniques, TP53 gene alterations were found in 59 (32%) of the 187 samples studied. Most of the TP53 changes (37%) were observed in exon 7. In patients with known follow up (median, 107 months), there was no significant association of the frequency of TP53 mutation with menopausal or nodal status, tumor size, or progesterone receptor status. TP53 gene alterations were more frequently present in estrogen receptor (ER)-negative (ER-) tumors (P = 0.04) and in tumors with an amplified HER2/NEU oncogene (P = 0.03). Univariate analysis showed that patients with a mutated TP53 in their primary tumors had shorter relapse-free (P = 0.01) and overall (P = 0.03) survival. Patients with a TP53 gene mutation in exon 8 may be identified as having a particularly rapid rate of relapse. In Cox multivariate regression analysis, which included age, menopausal status, lymph node status, tumor size, steroid-hormone-receptor status, and oncogene amplifications, both TP53 gene alteration and MYC amplification independently predicted poor prognosis, with relative hazard rates for TP53 and MYC of 1.8 and 1.6, respectively, in analysis for relapse-free survival and of 1.7 and 1.6, respectively, in analysis for overall survival. PMID: 8814449 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 820: J Soc Gynecol Investig. 1996 Jul-Aug;3(4):216-22. Immunologic characterization of tumor markers in human ovarian cancer cell lines. Kutteh WH, Miller DS, Mathis JM. Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, USA. OBJECTIVE: The purpose of this study was to evaluate the expression of a novel autologous ovarian tumor-associated antigen in eight human ovarian tumor cell lines compared with other ovarian tumor markers and products of oncogenes. METHODS: Autologous antibodies were eluted from human ovarian tumor-membrane fragments purified in our laboratory. These antibodies react with autologous ovarian tumor-associated antigens (AOTA) and have a high degree of specificity for human ovarian tumors. They do not bind to normal ovarian or nonovarian tissues, or to nonovarian neoplastic tissues. We evaluated eight human ovarian adenocarcinoma cell lines (2008, 2774, Caov-3, OVCAR-3, PA-1, SW 626, UCI 101, and UCI 107) by indirect immunofluorescence to determine the expression of AOTA relative to the ovarian cancer tumor marker CA 125 and the products of selected oncogenes (p 53, c-neu, and c-myc). RESULTS: The patterns and intensities of immunofluorescence correlated most closely between AOTA and c-neu. For example, AOTA and c-neu were detected in all eight cell lines and displayed very strong cytoplasmic fluorescence on cell lines 2774, UCI 101, and UCI 107. CA 125 was present in the cytoplasm of four of eight cell lines. A tumor suppressor gene product, p53, exhibited a nuclear staining pattern in six of eight cell lines. CONCLUSIONS: These data suggest that AOTA and the products of the c-neu oncogene may share certain epitopes. Current studies are underway to increase our understanding of the humoral response to ovarian cancer and the possible relationship to the expression of tumor oncogene products. Further characterization of AOTA will be necessary before early diagnostic tests can be developed. PMID: 8796833 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 821: Ann Rheum Dis. 1996 Jul;55(7):442-9. Localisation of apoptosis and expression of apoptosis related proteins in the synovium of patients with rheumatoid arthritis. Sugiyama M, Tsukazaki T, Yonekura A, Matsuzaki S, Yamashita S, Iwasaki K. Department of Orthopaedic Surgery, Nagasaki University School of Medicine, Japan. OBJECTIVES: To investigate whether apoptosis occurs in the synovium of rheumatoid arthritis (RA), and the intermediate molecules operating in this process. METHODS: DNA fragmentation was detected by in situ nick end labelling (ISNEL) in the synovium of patients with RA (n = 11) and control patients with femoral neck fracture (n = 5). The expression of proteins p53, p21WAFI/CIPI, c-myc, proliferating cell nuclear antigen (PCNA), and Bcl-2 was also examined by immunohistochemistry. RESULTS: ISNEL positive synovial cells with apoptosis specific morphology were detected in extremely limited areas in only two RA synovial tissue specimens. Proteins p53, p21WAFI/CIPI, and c-myc, known inducers of apoptosis or cell cycle arrest or both, were expressed in the sublining cells independent of ISNEL positive cells. PCNA, a marker for cell proliferation, was observed in the synovial lining cells. Bcl-2, an inhibitor of apoptosis, was expressed mainly in infiltrated lymphocytes and in parts of the sublining layer cells of RA; it also did not correspond with ISNEL staining. CONCLUSIONS: Our findings indicate that RA synovial cells undergo apoptosis in addition to cell proliferation, but the frequency of apoptosis was very low. We suspect that the apoptotic process in the RA synovium may be suppressed by over-expression of Bcl-2. Although expressed proteins p53, p21WAFI/CIPI, and c-myc were present in the RA synovium, these protooncogenes are probably not implicated in the apoptotic process. PMID: 8774162 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 822: Anticancer Res. 1996 Jul-Aug;16(4A):1707-17. Molecular genetics of malignant insulinoma. Pavelic K, Hrascan R, Kapitanovic S, Vranes Z, Cabrijan T, Spaventi S, Korsic M, Krizanac S, Li YQ, Stambrook P, Gluckman JL, Pavelic ZP. Department of Molecular Medicine, Ruder Boskovic Institute, Zagreb, Croatia. Malignant insulinoma is an rare form of cancer with poor prognosis and a reported 5-year survival of 35%. Relatively little is known about the etiology of this disease or of the oncogenes and tumor suppressor genes that participate in its genesis and progression. To address this issue, several protooncogenes, including K-ras, N-ras, erbB-2, erbB-3,c-myc, c-fos, c-jun were examined. Also analyzed was the expression of the growth factors TGF-alpha, EGF, and insulin as well as the EGF receptor (EGF-R), p53 and the putative anti-metastasis gene nm23-H1. These were examined in malignant insulinomas, benign insulinomas, pancreatic B cell hyperplasias and in normal endocrine pancreas. Normal endocrine pancreas showed moderate immunoreaction for c-myc and a strong reaction for insulin. All other parameters were negative. Benign pancreatic B cell hyperplasias were slightly or moderately positive for N-ras and TGF-alpha, and were weakly positive for EGF-R. They were strongly positive for c-myc and insulin. In malignant insulinomas there was strong immunoreaction for c-myc, TGF-alpha, N-ras, K-ras and p53. Insulin reaction was moderate or strong. Molecular genetic studies have been performed for the presence of activating point mutations in codon 12 of the c-K-ras oncogene. Mutations were detected using primer-mediated, mutant-enriched, polymerase chain reaction-restriction fragment length polymorphism analysis and were further characterized by allele-specific oligonucleotide hybridization. Four out of six patients with malignant insulinoma and two out of eight patients with benign insulinoma harbored K-ras point mutations at codon 12. All patients with mutated K-ras oncogene also had elevated levels of p53 protein as well as c-myc and TGF-alpha. In one extremely malignant case we found concomitant mutation at codon 12 of K-ras and codon 61 of the N-ras gene. Our data are consistent with the idea that malignant progression is accompanied by the progressive accumulation of multiple genetic lesions and suggest that activation of myc, TGF-alpha and ras genes may be early events in the development of insulinoma. PMID: 8712689 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 823: Carcinogenesis. 1996 Jul;17(7):1395-401. The human papillomavirus E6/E7 genes induce discordant changes in the expression of cell growth regulatory proteins. Pei XF. Department of Pathology, Georgetown University Medical Center, Washington, DC 20007, USA. The E6/E7 oncoproteins of human papillomavirus (HPV) types 16 and 18 are responsible for the efficient immortalization of human genital keratinocytes and we have recently reported that such immortalized cells display alterations in the expression of cyclin A, cyclin B, and cdc-2. To determine whether these alterations were the consequence of E6/E7 protein expression or whether they resulted from the process of cellular immortalization, we multiply-infected primary genital keratinocytes with a retrovirus expressing the HPV-18 E6/E7 genes and examined the cells for acute, pre-immortalization changes in several critical cell growth regulatory proteins including cyclin A, cyclin B, cdc-2, p53 and c-myc. In addition, we simultaneously evaluated the expression of the E6/E7, bcl-2 and involucrin genes to determine whether there were accompanying alterations in the expression of viral genes or in cellular genes related to cell apoptosis and the state of keratinocyte differentiation. The cell cycle regulating proteins (cyclin A, cyclin B, cdc-2 and p53) change significantly within days after retroviral infection. Cyclin B and cdc-2 increase over 4-fold by three passages and remain relatively constant thereafter through passage 21, whereas the levels of p53 protein decrease 25% by passage three. Increases in the expression of cyclin A, cyclin B and cdc-2, and decreases in p53 are therefore among the earliest observable changes in cell regulatory proteins following E6/E7 gene expression and may be important contributors to the development of cell immortalization. The expressions of viral E6/E7 genes, c-myc, bcl-2 and involucrin exhibit progressive changes with increased passage numbers until passage 21, presumably reflecting the selective outgrowth of immortalized cells. PMID: 8706240 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 824: Gan To Kagaku Ryoho. 1996 Jul;23(8):990-6. [Genetic abnormalities in lung cancer and their prognostic implications] [Article in Japanese] Mitsudomi T, Takahashi T. Dept. of Thoracic Surgery, Aichi Cancer Center Hospital, Japan. Recent advances in molecular biology have revealed various genetic lesions in lung cancer. Mutations of the K-ras gene, amplification or overexpression of myc family genes, erbB2 gene, or bcl2 gene are frequent genetic changes of oncogenes in lung cancer. Inactivation of tumor suppressor genes such as Rb gene, p53 gene, or p16 gene are also seen rather frequently. Furthermore, loss of heterozygosity at certain chromosomal arms such as 3p, 5q, 18q and 22q suggesting inactivation of yet unidentified tumor suppressor genes, also occurs in a significant proportion of lung cancers. Most of these genetic lesions have been reported to be associated with a poor prognostic outcome of the patients. However, great controversy exists as to whether a certain genetic lesion is really a prognostic marker. For example, although about 20 studies have been published, the prognostic implications of the p53 gene for patients with lung cancer still remain unclear. Little is known about the mechanism through which a certain genetic change affects the patient's prognosis. To ultimately improve the prognosis of patients with this deadly disease, definitive studies on which subsequent clinical trials can rely are much awaited. Publication Types: Review Review, Tutorial PMID: 8687234 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 825: Gan To Kagaku Ryoho. 1996 Jul;23(8):1004-9. [Evaluation of prognostic factors in gynecological cancer examined by molecular biological study] [Article in Japanese] Nagai N. Dept. of obstetrics and Gynecology, Hiroshima University School of Medicine, Japan. The usefulness of prognostic factors in gynecological cancer was evaluated using the oncogenes, tumor suppressor genes and DNA viruses detected with the molecular biological technique. In uterine cervical cancer, HPV types 16 and 18 are considered to have a high oncogenic risk, and are commonly associated with high grade CIN and invasive cancer under persistent HPV infection. C-myc overexpression in advanced stage and p53 mutation in HPV negative case are associated with poor survival. In endometrial cancer, oncogene activation and expression are less frequent than in cervical and ovarian cancer. K-ras point mutation (codon 12) tumors are more aggressive and c-erbB-2 overexpression are associated with metastasis and poor survival. In ovarian cancer, there are numerous abnormalities of oncogenes and tumor suppressor genes. Especially, EGF-R and PDGF-R alpha expression are associated with decreased survival. p53 mutation also decreases survival and response to chemotherapy. Recently. MSH2 (Lynch II syndrome) and BRCA1 gene are known to relate with familial ovarian cancer. Publication Types: Review Review, Tutorial PMID: 8687214 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 826: Mol Cell Biol. 1996 Jul;16(7):3878-83. C/EBPalpha regulation of the growth-arrest-associated gene gadd45. Constance CM, Morgan JI 4th, Umek RM. Department of Biology, University of Virginia, Charlottesville, 22903, USA. CCAAT/enhancer-binding protein alpha (C/EBPalpha) is expressed in postmitotic, differentiated adipocytes and is required for adipose conversion of 3T3-L1 cells in culture. Temporal misexpression of C/EBPalpha in undifferentiated adipoblasts leads to mitotic growth arrest. We report here that growth arrest- and DNA damage-inducible gene 45 (gadd45) is preferentially expressed in differentiated 3T3-L1 adipocytes similar to phenotype-associated genes. Furthermore, C/EBPalpha transactivates a reporter plasmid containing 1.5 kb of the gadd45 promoter region. The proto-oncogene myc, which inhibits adipocyte differentiation, abrogates C/EBPalpha activation of gadd45. gadd45 is known to be a target of the tumor suppressor p53 in a G1 checkpoint activated by DNA damage. Immunoprecipitation of radiolabeled proteins with conformation-specific antibodies revealed that wild-type p53 is expressed throughout 3T3-L1 adipocyte development, including the postmitotic period characterized by the accumulation of gadd45 and C/EBPalpha. A stable 3T3-L1 subline was engineered to express a dominant negative p53, human p53(143ala). The p53(143ala) subline differentiated to adipocytes and showed appropriate developmental expression of gadd45. These findings suggest that postmitotic growth arrest is coupled to adipocyte differentiation via C/EBPalpha stimulation of growth arrest-associated and phenotype-associated genes. PMID: 8668205 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 827: Hiroshima J Med Sci. 1996 Jun;45(2):69-73. Histological progression of follicular lymphoma associated with p53 mutation and rearrangement of the C-MYC gene. Takimoto Y, Takafuta T, Imanaka F, Kuramoto A, Sasaki N, Nanba K. Department of Internal Medicine, Hiroshima University, Japan. Follicular lymphoma is a low grade malignant lymphoma. However, some follicular lymphomas undergo histological transformation into higher grade malignant lymphomas. We recently encountered a diffuse large cell lymphoma which seemed to have progressed from a follicular lymphoma and which finally transformed into a small non-cleaved lymphoma. Each stage of the histological transformation was accompanied by increasing clinical grades of malignancy. It was suspected that in our patient a follicular lymphoma initially developed due to rearrangement of the BCL2 gene, and then underwent histological transformation into a diffuse large cell lymphoma, which was associated with p53 mutation. Subsequent rearrangement of C-MYC promoted the histological transformation of this diffuse large cell lymphoma into a small non-cleaved lymphoma. Our findings indicate that p53 mutation and rearrangement of C-MYC are involved in the histological transformation of follicular lymphomas into more advanced lymphomas. Publication Types: Case Reports PMID: 8810134 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 828: Anal Quant Cytol Histol. 1996 Jun;18(3):233-40. Cell cycle expression of p53 protein, c-Myc gene product and tyrosine-phosphorylation level determined by image analysis in human breast cancer cells. Caldani C, Far DF, Birtwisle-Peyrottes I, Ettore F, Rostagno P. Laboratory Cytometry, Centre Antoine Lacassagne, Nice, France. OBJECTIVE: To investigate the cell cycle expression of p53 protein, c-myc gene product and tyrosine phosphorylation level in human breast cancer cells. STUDY DESIGN: Using a multifluorescence imaging procedure, the concentration per cell in different phases of the cell cycle can be evaluated by analyzing the bivariate contour plot of DNA content versus antigen concentration. RESULTS: Low fluorescence intensity was observed in the G0/G1 phase for the three markers. The analysis of individual cells demonstrated that approximately 10% of cells were negative. During the G1/S transition, the fluorescence intensity of the three antigens increased rapidly. However, after the mild S-phase, the increase of c-myc was more marked than the tyrosine phosphorylation level, whereas p53 protein remained stable, with a slight tendency to decrease. CONCLUSION: This study confirmed that the p53 protein and c-myc gene product could perform a regulatory function in G1/S transition and, consequently, may play an important role in malignant transformation. Like-wise, the variations of tyrosine kinase activity were linked to cellular progression throughout the cell cycle and could be a useful marker of alteration in the growth-factor signaling pathway. Thus, the multifluorescence imaging procedure may provide useful information on the mechanisms of the cell cycle and on malignant transformation. PMID: 8790838 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 829: Cell Growth Differ. 1996 Jun;7(6):797-809. Expression of memory, differentiation, and repression of c-myc and p53 genes in human RD/TE-671 cells induced by a ureido-derivative of pyridine (UDP-4). Pappas IS, Sophianos D, Tzartos S, Tsiftsoglou AS. Department of Pharmaceutical Sciences, School of Health Sciences, Aristotle University of Thessaloniki, Greece. Human TE-671 cells have been used to study several aspects of neuroectodermal tumors in culture. Since the human TE-671 cell lines has been re-identified as a rhabdomyosarcoma (RD) rather than a medulloblastoma due to the presence of muscle-type nicotinic acetylcholine receptors, we re-investigated the nature of RD/TE-671 cells and characterized their differentiation induced by 2-(3-ethylureido)-6-methylpyridine (UDP-4), a potent inducer of differentiation of neoplastic cells. RD cells were also used for comparative studies. RD/TE-671 cells exposed to UDP-4 were differentiated irreversibly into postmitotic cells expressing mainly neurofilaments and, to a lesser extent, myoid proteins. In contrast to RD cells that expressed preferentially myoid and not neurofilament proteins (NFPs) upon treatment with UDP-4, differentiated RD/TE-671 cells exhibited characteristic dendritic processes and expressed NFPs (NFP68, NFP160, and NFP200), parvalbumin (calcium-binding protein), and neuron-specific enolase, as well as a small amount of vimentin and desmin. In addition, differentiated RD/TE-671 cells expressed memory for differentiation and underwent an irreversible limitation of proliferation, loss of clonogenic potential, selective repression of c-myc and p53 proto-oncogenes, and changes in cell surface architecture. Treatment of RD/ TE-671 cells with nerve growth factor or epidermal growth factor in the presence of UDP-4 did not alter the phenotype of differentiated cells, whereas co-treatment with 12-O-tetradecanoylphorbol-13-acetate and UDP-4 enhanced morphological differentiation. Therefore, we conclude that: (a) RD/TE-671 cells challenged with UDP-4 express memory to differentiate in the absence of inducer; (b) in contrast to RD cells, RD/TE-671 cells appear to be multipotent cells of neuroectodermal origin capable of differentiation into cells expressing neuronal rather than myoid proteins upon treatment with UDP-4; and (c) differentiation of RD/TE-671 cells leads to selective cessation of cell proliferation and repression of c-myc and p53 proto-oncogenes. PMID: 8780893 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 830: Am J Pathol. 1996 Jun;148(6):2017-25. Molecular characterization of primary mediastinal B cell lymphoma. Tsang P, Cesarman E, Chadburn A, Liu YF, Knowles DM. Department of Patholoy, Columbia University College of Physicians and Surgeons, New York, USA. Primary mediastinal B cell lymphoma (PMBL) is a diffuse large B cell lymphoma (DLCL) postulated to arise from noncirculating thymic B lymphocytes. Because of its distinctive clinical and morphological features and putative unique cellular origin, PMBL is generally considered a distinct clinicopathological entity. Little is known, however, about the molecular characteristics of PMBL. Therefore, we analyzed 16 PMBLs for molecular alterations involving the bcl-1, bcl-2, bcl-6, c-myc, H-ras, K-ras, N-ras, and p53 genes and for Epstein-Barr virus infection, which are commonly involved in lymphoid neoplasia. Employing a combination of Southern blotting and/or polymerase chain reaction and single-strand conformation polymorphism assays, we detected genetic alterations in 7 of the 16 (44%) PMBLs. Whereas the bcl-6 gene is rearranged in up to 45% of DLCLs, rearrangement of the bcl-6 gene was detected in only 1 of these 16 (6%) PMBLS. Point mutations of the 5' noncoding region of the c-myc gene were demonstrated in 3 other cases (19%), although c-myc gene rearrangements were not seen by Southern blotting. Missense point mutations of the p53 gene were identified in 3 additional PMBLs (19%). Alterations of the bcl-1, bcl-2, or ras genes and evidence of Epstein-Barr virus infection were not observed. In conclusion, a variety of molecular lesions occur in PMBLs and may be involved in their pathogenesis. This molecular genetic pattern bears little resemblance to that known for other B cell malignancies, including DLCL. In particular, the infrequent occurrence of bcl-6 gene rearrangement in PMBLs distinguishes them from other DLCLs of B cell origin, suggesting that PMBLs do not represent a distinct subtype of DLCL. PMID: 8669486 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 831: Leukemia. 1996 Jun;10(6):925-31. Control of apoptosis in hematopoiesis and leukemia by cytokines, tumor suppressor and oncogenes. Lotem J, Sachs L. Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel. Hematopoietic cells require certain cytokines including colony-stimulating factors and interleukins to maintain viability. Without these cytokines the program of apoptotic cell death is activated. Cells from many myeloid leukemias require cytokines for viability, and apoptosis is also activated in these leukemic cells after cytokine withdrawal resulting in reduced leukemogenicity. The same cytokines protect normal and leukemic cells from induction of apoptosis by irradiation and cytotoxic chemotherapeutic compounds. This suggests that decreasing the levels of viability inducing cytokines may increase the effectiveness of cytotoxic anti-cancer therapy. The susceptibility of normal and cancer cells to induction of apoptosis is also regulated by the balance between apoptosis-inducing genes such as the tumor suppressor wild-type p53, and c-myc and bax, and apoptosis-suppressing genes such as the oncogene mutant p53, and bcl-2 and bcl-XL. Cell susceptibility to induction of apoptosis in leukemic cells could be enhanced by increased expression of apoptosis-inducing genes and/or decreased expression of apoptosis-suppressing genes. Modulation of expression of apoptosis-regulating genes should thus also be useful for improvement of anti-cancer therapy. Publication Types: Review Review, Tutorial PMID: 8667646 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 832: Cancer Res. 1996 Jun 1;56(11):2506-9. Deletion of a nonconserved region of Bcl-2 confers a novel gain of function: suppression of apoptosis with concomitant cell proliferation. Uhlmann EJ, D'Sa-Eipper C, Subramanian T, Wagner AJ, Hay N, Chinnadurai G. Institute for Molecular Virology, Saint Louis University Health Sciences Center, St. Louis, Missouri 63110, USA. The Bcl-2 protein coded by the proto-oncogene bcl-2 is expressed in a variety of embryonic and postnatal tissues and is overproduced in several types of tumours. Bcl-2 expression suppresses apoptosis induced by a multitude of stimuli in diverse cell types without exerting significant effects on cell proliferation, and is believed to contribute to oncogenesis by extending cell survival. In certain B-cell lymphomas, chromosomal translocations result in a gain of function of Bcl-2 by overexpression. Here, we report that a deletion of a nonconserved region of human Bcl-2 (residues 51-85) confers a novel gain of function that not only suppresses apoptosis induced by the tumor suppressor protein p53 and the Myc oncoprotein but also permits continued cell proliferation. Our result raises the possibility that mutations within the bcl-2 gene may contribute to oncogenesis by both suppressing apoptosis and facilitating cell proliferation. PMID: 8653686 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 833: Radiat Res. 1996 Jun;145(6):714-21. Expression of lethal mutations is suppressed in neoplastically transformed cells and after treatment of normal cells with carcinogens. Mothersill C, Lyng F, O'Reilly S, Harney J, Seymour CB. Dublin Institute of Technology, Ireland. Recent evidence from our laboratory suggests that the fraction of cells with lethal mutations is lost from the population by apoptosis. The relationship of this process to genetic instability and carcinogenesis is unclear. To examine this, tumorigenic cell populations derived from spontaneously occurring, neoplastically transformed C3H 1OT1/2 foci and from radiation-induced foci were compared with wild-type C3H 10T1/2 cell populations to determine the frequency of induction of lethal mutations postirradiation. Lethal mutations did not occur in the progeny of cells from type 3 foci derived from cultures of spontaneously occurring or radiation-induced neoplastically transformed cells but were very frequent in the progeny of irradiated wild-type cells. Normal human cells (HPV-immortalized human keratinocytes and primary human normal uroepithelium) were then treated with carcinogens or transfected with the Ha-ras oncogene to see if these carcinogenic events affected the yield of lethal mutations postirradiation. In each case, cells which were exposed to a carcinogenic agent had reduced numbers of lethal mutations, elevated levels of stable p53 and Bcl-2 proteins and reduced evidence of apoptosis. It is suggested that lethal mutations may represent an active safety mechanism which may deal with radiation-induced genomic instability and which is disabled early in carcinogenesis. PMID: 8643831 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 834: Mol Cell Endocrinol. 1996 May 17;119(1):61-8. Molecular and cellular responses to DNA damage in a murine pituitary adenoma cell line. Woloschak M, Yu A, Xiao J. Department of Medicine, Mt. Sinai School of Medicine, New York, NY 10029, USA. Loss of cell cycle control and the inability of the cell to repair DNA at cell cycle checkpoints results in the propagation of genetic lesions which ultimately leads to cancer. To further our understanding of these pathways in pituitary tumorigenesis, we have investigated the effects of DNA damage by gamma radiation in a murine pituitary adenoma (AtT20) cell line with attention to cell cycle checkpoint responses, the induction of apoptosis, and the expression of known regulators of these processes. Irradiated cells exhibited characteristic morphologic changes of apoptosis beginning at 24 h, which included cell shrinkage, chromatin condensation, and cytoplasmic vacuolization, yet the ability to exclude trypan blue was retained for several days. DNA fragmentation could be demonstrated by ethidium bromide staining beginning at 24 h post-irradiation. By propidium iodide staining and flow cytometry, irradiated cells demonstrated G1 and G2 arrest at 24 h, followed at 48 h by a shift to a sub-G1 position of the apoptotic cell population. The G1 arrest coincided with an induction of p53 protein by Western blot analysis which peaked at 4 h post-radiation and persisted beyond 48 h. Expression of c-myc in irradiated cells was found to progressively decrease at 12, 24, and 48 h. Basal expression of the bcl-2 gene in AtT20 cells was found to be 15-fold higher than in normal mouse pituitary by RNase protection assay. Bcl-2 mRNA and protein levels, however, remained unchanged at 24 and 48 h following gamma-irradiation, suggesting that apoptosis occurs independently of bcl-2 gene expression in these cells following this stimulus, as reported in other cell types. We conclude that AtT20 cells undergo G1 and G2 arrest following DNA damage and that a significant proportion of cells then undergo apoptosis. The G1 arrest at 24 h is concurrent with a strong induction of p53 protein, while c-myc expression progressively diminishes. Bcl-2 is highly expressed in this cell line. The absence of variation in bcl-2 expression during apoptosis could be related to its high basal level in these cells. PMID: 8793854 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 835: Oncogene. 1996 May 2;12(9):1847-54. Induction of c-myc mediated apoptosis in SV40-transformed rat fibroblasts. Lenahan MK, Ozer HL. Department of Microbiology and Molecualr Genetics, UMDNJ-New Jersey Medical School, Newark, 07103-2714, USA. The ability of SV40 T antigen to block apoptosis was investigated in Rat1-A fibroblasts expressing an estrogen-dependent c-myc construct, mycER (Eilers et al., 1989). These RatmycER cells undergo apoptosis upon activation of c-myc by estradiol under conditions of serum deprivation. Under such conditions SV40-transfected derivatives of RatmycER undergo apoptosis as evidenced by rapid cell death, characteristic morphological changes and DNA fragmentation in a manner indistinguishable from the parental cell line, indicating that T antigen is not able to protect against myc-induced apoptosis. In as much as it had been reported that myc-mediated apoptosis involves wild-type p53 in other systems and T antigen is known to bind and inhibit p53 function, we examined these two polypeptides under different experimental conditions. In all cases, the great majority of the p53 in the SV40 transfectants was found to be in complexes with T antigen. Furthermore, the residual p53 in the uncomplexed state was not sufficient to transactivate an endogenous promoter, WAF1/p21. These data indicate that the failure of T antigen to block apoptosis cannot be attributed to defective function of T antigen and suggest that myc-mediated apoptosis may involve a p53-independent pathway in these cells. PMID: 8649844 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 836: J Cell Biochem. 1996 May;61(2):172-81. Normal and transforming Ras are differently regulated for posttranslational modifications. Yamada-Okabe T, Doi R, Yamada-Okabe H. Department of Hygiene, Yokohama City University, School of Medicine Japan. Point mutation of the c-H-ras gene significantly increases cellular transforming activities of Ras. Since posttranslational modification and subsequent membrane localization are essential for the biological activities of Ras, we examined whether or not the mutation also affects these two factors. The normal (Gly(12)) or the transforming (Val(12)) c-H-ras gene was expressed in NIH3T3 cells using a metallothionein promoter. Expression of either type of Ras was efficiently induced by the cadmium treatment of these cells, and immunoprecipitation of metabolically labeled cell extracts revealed that both normal and transforming Ras were expressed as four differently migrating forms on SDS-polyacrylamide gels, two of which were slower migrating cytosolic precursors and the other two were faster migrating membrane-bound forms. There was no significant difference in half lives between normal and transforming Ras; however, posttranslational modification was quite different between the two types of Ras. Transforming Ras was processed and became membrane-bound forms much more efficiently than normal Ras. Interestingly, posttranslational modification and membrane localization of Ras was significantly inhibited when the c-myc oncogene was co-expressed with Ras. In contrast to the c-myc oncogene, expression of either wild type or mutant p53 did not affect the posttranslational modification of Ras, suggesting that the c-myc oncogene specifically impairs the posttranslational modification of Ras. PMID: 9173082 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 837: Genes Chromosomes Cancer. 1996 May;16(1):21-30. Molecular heterogeneity of B-lineage diffuse large cell lymphoma. Volpe G, Vitolo U, Carbone A, Pastore C, Bertini M, Botto B, Audisio E, Freilone R, Novero D, Cappia S, De Giuli P, Mazza U, Resegotti L, Palestro G, Saglio G, Gaidano G. Laboratorio di Medicina, Universita di Torina, Italy. B-lineage diffuse large cell lymphoma (B-DLCL) arising de novo is characterized by a marked degree of clinical heterogeneity. To determine whether or not the clinical heterogeneity of de novo B-DLCL is reflected by heterogeneity in the molecular features of these tumors, we investigated the pattern of distribution of several genetic lesions in 70 cases of de novo B-DLCL at diagnosis. The panel of genetic lesions tested comprised the molecular alterations most frequently detected in B-DLCL, including rearrangements of BCL2, BCL6, and MYC as well as deletions of 6q and mutations of TP53. One or more genetic lesions were detected in 39/70 cases of B-DLCL. Isolated structural alterations of BCL2, BCL6, 6q or TPS3 were detected in 8/70, 10/70, 11/70, and 3/70 cases, respectively. No isolated MYC lesions were detected. Six cases carried different combinations of two genetic lesions, including lesions of BCL2 + BCL6 (1 case), BCL2 + MYC (1 case), BCL2 + 6q (2 cases), or BCL6 + 6q (2 cases). One case had accumulated three genetic lesions, namely a rearrangement of BCL2 and BCL6 and a mutation of TPS3. Overall, these data show that multiple distinct patterns of genetic lesions may associate with de novo B-DLCL, indicating that the molecular pathogenesis of this group of lymphomas is characterized by a high degree of molecular heterogeneity. PMID: 9162193 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 838: Nippon Geka Gakkai Zasshi. 1996 May;97(5):375-80. [Genetic alterations and DNA-based diagnosis in breast cancer] [Article in Japanese] Matsumoto S, Emi M, Kasumi F, Nakamura Y. Department of Molecular Biology, Nippon Medical School, Kawasaki, Japan. Human carcinomas are generally considered to develop through the accumulation of various genetic abnormalities. The major types of genetic alterations that are frequently observed in breast cancer are amplification of protooncogenes (MYC, ERBB2); mutation of TP53; and loss of heterozygosity on chromosomes 1, 3p, 8p, 11p, 13q, 17q, 17, and 22q. The latter may correspond to losses or inactivations of tumor suppressor genes. Recently, two major distinct breast susptibility genes were isolated, namely BRCA1 and BRCA2. We performed PCR-SSCP analysis to determine the role of the BRCA1 gene in Japanese breast cancer and investigated how multiple genetic alterations contribute to tumor development and/or progression in primary breast cancer, using a large number of tumor materials. Publication Types: Review Review, Tutorial PMID: 8709940 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 839: Anticancer Res. 1996 May-Jun;16(3A):1209-12. Terminal differentiation in a non-small-cell bronchopulmonary carcinoma correlates with increased expression of p53. Liscia E, Riou D, Slavoshian S, Boesch S, Lebert V, Tomasoni C, Dabouis G, Biard JF, Roussakis C. ISOMER (Institut Substances et Organismes de la MER), Faculte de Pharmacie, Nantes, France. We studied the pharmacomodulating effects of a marine substance, bistramide D, which is capable of inducing terminal differentiation on the expression of the c-erb-B1, ras, src, myc and p53 genes in the NSCLC-N6 cell line established from a non-small cell lung carcinoma. Analysis (subsequent to treatment) demonstrated that among the genes for which it was possible to detect expression, namely c-erb-B1, c-myc and p53, only the expression of the p53 gene varied significantly. The increase of the expression rate of the p53 gene underlines its prominent role in the control of cell proliferation and differentiation. PMID: 8702238 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 840: Acta Urol Belg. 1996 May;64(2):47-9. New generation of prognostic factors in muscle invasive bladder cancer. Abi-Aad AS. PMID: 8701811 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 841: Tumori. 1996 May-Jun;82(3):205-9. Role of three cancer "master genes" p53, bcl2 and c-myc on the apoptotic process. Chiarugi V, Ruggiero M. Laboratory of Molecular Biology, University of Florence, Italy. We review some of the most recent developments concerning three genes involved in human cancer: p53, bcl2 and c-myc. Recent data have demonstrated that the bcl2 gene protects tumor cells from apoptosis induced by a variety of agents, including ionizing radiation, and is thus related to resistance to DNA-damaging therapeutic agents. The p53 tumor suppressor gene, however, has been related with growth arrest, apoptosis and thus with selective sensitivity to the killing effects of ionizing radiation and DNA-damaging drugs. This functional antagonism between the two genes was recently substantiated in molecular terms by demonstration of reciprocal down-regulation due to the presence of a p53-dependent transcription silencer in the untranslated region of the bcl2 gene. Growth arrest in the G1 phase of the cell cycle and induction of apoptosis are two distinct and dissectable functions of p53: bcl2 is able to antagonize the induction of apoptosis by p53, but not the growth arrest in G1. However, coexpression of bcl2 and of the oncogene c-myc efficiently antagonizes effects of p53 on G1 arrest and apoptosis, thus suggesting a cooperation between the two oncogenes. In addition, c-myc disrupts other functions of genetic control in the early G1 phase of the cell cycle including the expression of D1 cyclin. We believe that knowledge of the functional/molecular interactions between these three genes involved in human cancer is a fundamental prerequisite to improve the knowledge on prognosis and to design innovative therapeutic approaches. Publication Types: Review Review, Tutorial PMID: 8693593 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 842: Br J Haematol. 1996 May;93(2):475-86. Large-cell variants of mantle cell lymphoma: cytologic characteristics and p53 anomalies may predict poor outcome. Zoldan MC, Inghirami G, Masuda Y, Vandekerckhove F, Raphael B, Amorosi E, Hymes K, Frizzera G. Department of Pathology, Division of Hematopathology/Molecular Pathology, New York University Medical Center, NY, USA. Large-cell variants are uncommon in mantle cell lymphoma (MCL). Here we describe the pathologic and clinical findings in five patients with large-cell lymphoma related to MCL (L-MCL), and compare them to a group of classic small-cell MCL (s-MCL) cases. Histologically, the MC origin of the large cells was evinced by their association with a small mantle cell component in the same tissue, or their distribution in a classic mantle zone pattern, or their development in a patient with previous s-MCL. The large cells were either pleomorphic mantle cells (case 1) or transformed blast-like cells (case 2-5). The median nuclear diameter, median nuclear area and proliferation index of L-MCLs and s-MCLs, were statistically different. Immunophenotypic characterization of four specimens of L-MCL and 10 of s-MCLs with a large panel of antibodies showed the classic findings of MCL, i.e. the IgM+ D+/-, CD5+, CD10-, CD23- phenotype in all cases except two (one CD5- and one CD23+), and the association with a loose follicular dendritic cell network. Two of four L-MCLs and 5/10 s-MCLs demonstrated rearrangements of the bcl-1 gene by Southern blot or by polymerase chain reaction (PCR); 2/4 L-MCLs and 1/9 s-MCLs had p53 mutations on single-strand conformation polymorphism analysis; none of the 14 specimens showed rearrangement of bcl-2 by PCR or bcl-6 and c-myc by Southern blot. All patients with 'transformed' histology (versus 37% of all others) died of lymphoma; their survival (15-18 months; median 17) was much shorter than that of all the others (28-117+ months; median 43) (P=0.0035). All three patients with p53 anomalies, two of whom had tumours with transformed histology, died of their disease in a short time (15, 18 and 28 months). In contrast, the presence of bcl-1 rearrangements did not have prognostic implications. This study documents the existence of large-cell variants of MCL and the poor prognosis associated with the 'transformed' cytologic type and/or p53 abnormalities. PMID: 8639452 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 843: Chest. 1996 May;109(5 Suppl):130S-134S. Oncogenes and antioncogenes in lung tumorigenesis. Giaccone G. Department of Oncology, Free University Hospital, Amsterdam, The Netherlands. The role of oncogenes and antioncogenes in lung tumorigenesis is discussed in this review, with particular emphasis on their prognostic significance. Mutations in the ras family of oncogenes, overexpression of the myc and neu families of oncogenes, and mutations of p53, the recessive tumor suppressor gene, occur with differing frequencies in small cell lung cancer and non-small cell lung cancer, and are usually associated with a poor prognosis. Loss of heterozygosity, notably on chromosomes 3p, 5q, 9p, 13q, and 17p, is a common feature in lung carcinomas and its importance is also discussed. Publication Types: Review Review, Tutorial PMID: 8635391 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 844: Gynecol Oncol. 1996 May;61(2):227-32. Mitotic count, nuclear atypia, and immunohistochemical determination of Ki-67, c-myc, p21-ras, c-erbB2, and p53 expression in granulosa cell tumors of the ovary: mitotic count and Ki-67 are indicators of poor prognosis. King LA, Okagaki T, Gallup DG, Twiggs LB, Messing MJ, Carson LF. Department of Obstetrics and Gynecology, Medical College of Georgia, Augusta, 30912, USA. In spite of extensive research, the behavior of granulosa cell ovarian tumors remains unpredictable and is complicated by the lack of prognostic factors in early-stage disease. Forty patients with granulosa cell tumors were identified from tumor registries and data were analyzed for patient outcome. Mitotic count and nuclear atypia were determined at time of histological review. Paraffin-embedded archival tumor tissues from 32 of 40 patients were available, and immunohistochemical testing for Ki-67, c-myc, p21-ras, c-erbB2, and p53 was performed on archival tissues. Results were correlated with patients' outcome. Mitotic count and Ki-67 were found to be negatively associated with survival in granulosa cell tumors. Nuclear atypia, c-myc, p21-ras, c-erbB2, and p53 were not found to be of prognostic significance. PMID: 8626138 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 845: Cancer Res. 1996 May 1;56(9):1991-6. Apoptotic response to oncogenic stimuli: cooperative and antagonistic interactions between c-myb and the growth suppressor p53. Sala A, Casella I, Grasso L, Bellon T, Reed JC, Miyashita T, Peschle C. Jefferson Cancer Institute, Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA. c-myb, a protooncogene prevalently expressed in the hematopoietic tissue, is a transcription factor that contains a DNA-binding domain and an acidic domain and is able to transactivate specific viral and cellular genes. In this report, we show that c-myb can stimulate apoptosis in both the murine promyelocytic 32D and the human osteosarcoma SAOS2 cell lines when coexpressed with p53. Apoptosis is accompanied by increased transactivation of the cell death-associated BAX gene. This effect is c-myb specific, because B-myb is not able to cooperate with p53 in the induction of BAX transcription and apoptosis. Immunoprecipitation studies and gel shift analysis indicate that c-myb does not directly interact with the BAX promoter or the p53 protein but, rather, cooperates through an indirect mechanism. Consistent with the existence of a functional link between c-myb and p53, we also observed that c-myb represses p53-induced activation of the WAF-1 promoter and induces proliferation of SAOS2 cells growth arrested by p53. These results might contribute to the elucidation of the mechanisms underlying p53-dependent pathways of oncogene-induced apoptosis and provide a further example of DNA-binding independent myb activity. PMID: 8616838 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 846: Cancer. 1996 Apr 15;77(8 Suppl):1711-6. Apoptotic cell death and its relationship to carcinogenesis in colorectal carcinoma. Tsujitani S, Shirai H, Tatebe S, Sugamura K, Ohfuji S, Gomyo Y, Maeta M, Ito H, Kaibara N. Department of Surgery I, Tottori University, Yonago, Japan. BACKGROUND. Apoptotic cell death plays an important role in the proliferation and turnover of cells in various tumors. The relationship between apoptosis and cell proliferation was studied to determine each of their roles in colorectal carcinogenesis. METHODS. Apoptotic cells were identified by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method. The occurrence of apoptosis was examined in colorectal cancer that had invaded the submucosa. Specimens were obtained from 38 cases of cancer with adenoma and 29 cases of cancer de novo. Apoptotic indices (AIs) as percentages of TUNEL-positive cells relative to the number of tumor cells and Ki-67 labeling indices (PI) were investigated. The relationship between the frequency of apoptosis and the expression of p53 and c-myc proteins was also investigated. RESULTS. In cancer with adenoma, the ratio of AI/PI in adenoma cells was significantly higher than that of cancer cells (P < 0.0001). Mean AIs of cancer with adenoma were significantly higher than those of cancer de novo particularly in the flat-type cancers (P < 0.05). Among p53 negative tumors, the ratio of AI/PI for cancer de novo was significantly lower than that for cancer with adenoma (P < 0.05). AI of cancer de novo was lower than that of cancer with adenoma in cases with overexpression of c-myc protein (P < 0.05), whereas there was no significant difference in the ratio of AI/PI between cancer de novo and cancer with adenoma. CONCLUSIONS. Colorectal carcinogenesis is related to the inhibition of apoptosis and to the augmentation of proliferative activity both in cancer with adenoma and in cancer do novo. A reduction of the rate of apoptosis as compared with that of cell proliferation might explain the rapid-growing nature of cancer de novo particularly in cases with the flat-type appearance. PMID: 8608567 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 847: Exp Cell Res. 1996 Apr 10;224(1):52-62. Characterization of c-myc-transformed rat fibroblasts resistant to apoptosis induced ny growth factor deprivation. Dhanaraj, SN, Marcus AM, Korah RM, Iwata K, Small MB. Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, 07103-2714, USA. Under appropriate conditions (e.g., growth factor withdrawal), the deregulated expression of c-myc in rodent fibroblasts leads to substantial cell death due to apoptosis. To better understand this process, we selected for c-myc-transformed Rat1A fibroblasts that were resistant to growth factor deprivation-induced cell death. One clonal isolate exhibited prolonged survival in serum-free medium and displayed reduced levels of apoptosis-related DNA fragmentation. These cells were also resistant to induction of apoptosis by the protein kinase inhibitor staurosporine. They retained a transformed cell phenotype and expressed the proviral human c-myc allele in an unaltered fashion, strongly indicating that the mutation of a cellular gene other than c-myc accounts for the apoptosis-resistant phenotype. The results of somatic cell hybrid analysis of this cell line are consistent with a recessive mutation. Our findings suggest a novel mechanism for abrogation of apoptosis in neoplastic cells and provide a model system for the study of its role in tumorigenesis and resistance to antineoplastic therapy. PMID: 8612691 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 848: Nippon Rinsho. 1996 Apr;54(4):1060-5. [Genetic events during development of esophageal squamous cell carcinoma] [Article in Japanese] Sasaki H, Watanabe H, Terada M. Genetics Division, National Cancer Center Research Institute. Various molecular genetic abnormalities have been reported in esophageal carcinoma. These include amplification of the chromosome 11q13 region containing cyclin D1, EXP1 and EMS1 genes, and the oncogenes, the epidermal growth factor receptor gene, EGFR/c-ERBB1, and c-myc. Loss of heterozygosity (LOH) at several chromosome loci and point mutation of the p53 and p16/CDKN2 tumor suppressor genes have also been described. Mutations of p53 gene and LOH at 3p and 9q loci were investigated in esophageal epithelial dysplasia. In contrast, amplification of cyclin D1, EGFR, c-myc and other genes was accumulated in advanced tumors with invasion. Cyclin D1 amplification is found more in metastatic lesions than in primary tumors. Publication Types: Review Review, Tutorial PMID: 8920674 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 849: J Virol. 1996 Apr;70(4):2095-100. Moloney murine leukemia virus-induced lymphomas in p53-deficient mice: overlapping pathways in tumor development? Baxter EW, Blyth K, Donehower LA, Cameron ER, Onions DE, Neil JC. Department of Veterinary Pathology, University of Glasgow, Bearsden, United Kingdom. The effect of Moloney murine leukemia virus (MoMLV) infection was examined in mice lacking a functional p53 gene. Virus-infected p53-/- mice developed tumors significantly faster than uninfected p53-/- or virus-infected p53+/+ littermates. However, the degree of synergy between MoMLV and the p53 null genotype was weaker than the synergy between either of these and c-myc transgenes. A similar range of T-cell tumor phenotypes was represented in all p53 genotype groups, including p53-/- mice, which developed thymic lymphomas as the most common of several neoplastic diseases. Lack of p53 was associated with higher rates of metastasis and the ready establishment of tumors in tissue culture. Loss of the wild-type allele was a common feature of tumors in p53+/- mice and was complete in tumor cells in vitro, but this appeared to occur by a mechanism other than proviral insertion at the wild-type allele. A lower average MoMLV proviral copy number was observed in tumors of the p53 null and heterozygote groups, suggesting that the absence of a functional p53 gene reduced the number of steps required to complete the malignant phenotype. Mink cell focus-forming virus-like proviruses were detected in tumors of all infected mice but were relatively rare in p53 null mice. Analysis of c-myc, pim-1, and pal-1 showed that these loci were occupied by proviruses in some cases but at similar frequencies in p53 wild-type and null mice. In conclusion, while inactivation of p53 in the germ line predisposes mice to tumors similar in phenotype to those induced by MoMLV, it appears that virus-induced tumors generally occur without p53 loss. We speculate that a bcl-2-like function carried or induced by MoMLV may underlie this p53-independent pathway. PMID: 8642629 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 850: Carcinogenesis. 1996 Apr;17(4):691-8. Faulty DNA polymerase delta/epsilon-mediated excision repair in response to gamma radiation or ultraviolet light in p53-deficient fibroblast strains from affected members of a cancer-prone family with Li-Fraumeni syndrome. Mirzayans R, Enns L, Dietrich K, Barley RD, Paterson MC. Molecular Oncology Program, Cross Cancer Institute, Edmonton, Alberta, Canada. Dermal fibroblast strains cultured from affected members of a cancer-prone family with Li-Fraumeni syndrome (LFS) harbor a point mutation in one allele of the p53 tumor suppressor gene, resulting in loss of normal p53 function. In this study we have examined the ability of these p53-deficient strains to carry out the long-patch mode of excision repair, mediated by DNA polymerases delta and epsilon, after exposure to 60Co gamma radiation or far ultraviolet (UV) (chiefly 254 nm) light. Repair was monitored by incubation of the irradiated cultures in the presence of aphidicolin (apc) or 1-beta-D-arabinofuranosylcytosine (araC), each a specific inhibitor of long-patch repair, followed by measurement of drug-induced DNA strand breaks (reflecting non-ligated strand incision events) by alkaline sucrose velocity sedimentation. The LFS strains displayed deficient repair capacity in response to both gamma rays and UV light. The repair anomaly in UV-irradiated LFS cultures was manifested not only in the overall genome, but also in the transcriptionally active, preferentially repaired c-myc gene. Using autoradiography we also assessed unscheduled DNA synthesis (UDS) after UV irradiation and found this conventional measure of repair replication to be deficient in LFS strains. Moreover, both apc and araC decreased the level of UV-induced UDS by approximately 75% in normal cells, but each had only a marginal effect on LFS cells. We further demonstrated that the LFS strains are impaired in the recovery of both RNA and replicative DNA syntheses after UV treatment, two molecular anomalies of the DNA repair deficiency disorders xeroderma pigmentosum and Cockayne's syndrome. Together these results imply a critical role for wild-type p53 protein in DNA polymerase delta/epsilon-mediated excision repair, both the mechanism operating on the entire genome and that acting on expressed genes. PMID: 8625479 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 851: J Pathol. 1996 Mar;178(3):343-51. Proto-oncogene expression in human glomerular diseases. Takemura T, Okada M, Akano N, Murakami K, Hino S, Yagi K, Takekoshi Y, Yoshioka K. Department of Pediatrics, Kinki University School of Medicine, Osaka, Japan. The expression of the protein products and mRNA of c-fos, c-myc, p53, and c-raf was examined in normal renal tissues and biopsy specimens from 73 patients with various glomerular diseases. Immunofluorescent staining showed that there were cell nuclei stained for c-Fos, c-Myc, and p53, and cytoplasm positive for c-Raf, in the glomeruli of patients with proliferative types of glomerulonephritis, including IgA nephritis and lupus nephritis, and in patients with focal glomerular sclerosis. Glomerular expression of c-fos and c-myc mRNA was detected by in situ hybridization. The number of proto-oncogene-positive glomerular cells was significantly higher in lupus nephritis, IgA nephritis, and focal segmental sclerosis, as compared with minimal change nephrotic syndrome and normal specimens. In IgA nephritis, the population of glomerular cells positive for c-Fos and c-Myc and the grade of c-Raf immunoreactivity were significantly correlated with the proportion of proliferating cell nuclear antigen (PCNA)-positive glomerular cells, with histological grading of mesangial hypercellularity and matrix increase, and with the magnitude of proteinuria. These data indicate that proto-oncogene expression is associated with mesangial proliferation and matrix expansion in proliferative types of glomerulonephritis and in focal glomerular sclerosis. PMID: 8778342 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 852: Leukemia. 1996 Mar;10(3):447-55. Resistance to apoptotic cell death in a drug resistant T cell leukaemia cell line. Geyp M, Ireland CM, Pittman SM. Children's Leukaemia and Cancer Research Centre, Prince of Wales Children's Hospital, Sydney, Australia. In this study, we investigated the responses of the T cell leukaemia cell line, CCRF-CEM, and a vincristine-resistant subline, CEM/VCR R, to the induction of cell death by serum withdrawal. This treatment was used to overcome any contribution of P-glycoprotein-mediated drug resistance to the responses of the CEM/VCR R cells. Following serum withdrawal both cell lines exhibited typical apoptotic responses including morphological changes and nucleosomal cleavage of the DNA. However, using several different assays for cell death the CEM/VCR R cell line was shown to undergo apoptosis at a slower rate than the parental CCRF-CEM cell line. Expression of c-Myc, Bcl-2 and p53 was found to be similar in both cell lines, discounting involvement of these proteins in the observed difference in apoptotic response. Given our previous finding that reorganisation of tubulin is involved in apoptosis, we examined the expression of alpha-, beta- and acetylated alpha-tubulin in the parental and resistant lines. The CEM/VCR R cell line had altered tubulin expression when compared to that of the CCRF/CEM line. Transnuclear microtubule networks were observed in log phase CEM/VCR R cells. In addition, increased expression of the acetylated form of the alpha-tubulin isotype suggested that a more stable microtubule network was present in the CEM/VCR R cells. These findings imply that the drug-resistance phenotype in the CEM/VCR R cells may involve the suppression of apoptosis, and that the development of an altered microtubule network may contribute to this suppression. PMID: 8642860 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 853: J Exp Med. 1996 Mar 1;183(3):971-7. Human germinal center B cells express the apoptosis-inducing genes Fas, c-myc, P53, and Bax but not the survival gene bcl-2. Martinez-Valdez H, Guret C, de Bouteiller O, Fugier I, Banchereau J, Liu YJ. Schering-Plough, Laboratory for Immunological Research, Dardilly, France. During T cell-dependent antibody responses, B cells within germinal centers (GC) alter the affinity of their antigen receptor by introducing somatic mutations into variable region of immunoglobulin (IgV) genes. During this process, GC B cells are destined to die unless positively selected by antigens and CD40-ligand. To understand survival/death control of germinal center B cell, the expression of four apoptosis-inducing genes, Fas, c-myc, Bax, and P53, together with the survival gene bcl-2, has been analyzed herein among purified tonsillar naive, GC, and memory B cells. IgD+CD38- naive B cells were separated into CD23- (mature B cell [Bm]1) subset and CD23+ (Bm2), IgD-CD38+ GC B cells were separated into subsets of CD77+ centroblasts (Bm3) and CD77- centrocytes (Bm4), whereas IgD-CD38- cells represented the Bm5 memory B cell subset. Sequence analysis of IgV region genes indicated that somatic hypermutation was triggered in the Bm3 centroblast subset. Here we show that bcl-2 is only detectable with naive (Bm1 and 2) and memory B cell (Bm5) subsets, whereas all four apoptosis-inducing genes were most significantly expressed within GC B cells. Fas was equally expressed in Bm3 centroblasts and Bm4 centrocytes, whereas Bax was most significantly expressed in Bm4 centrocytes. c-myc, a positive regulator of cell cycle, was most significantly expressed in proliferating Bm3 centroblasts, whereas P53, a negative regulator of cell cycle, was most signficantly expressed in nonproliferating Bm4 centrocytes. The present results indicate that the survival/death of GC B cells are regulated by the up- and downregulation of multiple genes, among which the expression of c-myc and P53 in the absence of bcl-2 may prime the proliferating Bm3 centroblasts and nonproliferating Bm4 centrocytes to apoptosis. PMID: 8642300 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 854: Cell Growth Differ. 1996 Feb;7(2):173-8. Epidermal growth factor-induced apoptosis in A431 cells can be reversed by reducing the tyrosine kinase activity. Gulli LF, Palmer KC, Chen YQ, Reddy KB. Department of Pathology, Wayne State University, Detroit, Michigan 48201, USA. A431 cells overexpress epidermal growth factor receptors (EGF-Rs) and are inhibited by EGF. We show that treatment of A431 cells with 10 nM EGF induced a 15-fold increase in EGF-R autophosphorylation, leading to inhibition of cell proliferation and morphological features of apoptosis. However, at a lower concentration of EGF (0.01 nM), there is a 2-fold increase in EGF-R autophosphorylation and increased cell proliferation when compared to untreated cells. EGF treatment is associated with increased expression of c-myc and decreased expression of mutant p53 and p21/WAF protein. When A431 cells were simultaneously treated with 10 nM EGF and EGF-R antibody, there was a significant reduction in EGF-R autophosphorylation that was associated with increased cell proliferation. Based on these results, we postulate that overexpression of EGF-R could allow for selective growth advantage for tumor cells in the presence of normal or decreased ligand availability. However, excessive ligand binding would result in deregulated growth signaling, leading to growth inhibition and programmed cell death. PMID: 8822200 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 855: Toxicol Appl Pharmacol. 1996 Feb;136(2):229-35. Metallothionein-I and -II knock-out mice are sensitive to cadmium-induced liver mRNA expression of c-jun and p53. Zheng H, Liu J, Choo KH, Michalska AE, Klaassen CD. Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City 66160-7417, USA. Zinc pretreatment has been shown in vitro (rat myoblasts) to induce metallothionein (MT) and inhibit cadmium (Cd)-induced protooncogenes c-myc and c-jun mRNA levels. therefore, the purpose of this study was to determine whether the mRNA expression of the protooncogene c-jun as well as the tumor suppressor gene p53 is increased by Cd in the intact animal and, more specifically, in the target organ for Cd toxicity, the liver. Additionally, modulation of the expression of these genes was investigated in the absence of MT. The effect of CdCl2 on the mRNA levels of c-jun and p53 was studied in livers of C57BL/6J (control) and MT-null mice by Northern- and slot-blot analyses. The mRNA for c-jun and p53 were increased by Cd in a dose-dependent fashion. In the control mice, Cd induced c-jun mRNA (5-fold) at 3 and 12 hr and p53 mRNA (1.8- to 2-fold) at 6 and 12 hr. Compared to controls, the MT-null mice were more sensitive to the Cd-induced gene expression. The magnitude of the inductions was more pronounced and the elevated mRNA levels of c-jun and p53 were seen at lower doses of Cd (10mumol/kg in MT-null mice vs 40 mmol/kg in control mice). In conclusion, these data demonstrate that Cd induces mRNA expression of the protooncogene c-jun and tumor suppressor gene p53 in liver, and that MT modulates this effect. PMID: 8619230 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 856: Br J Haematol. 1996 Feb;92(2):375-81. Richter's syndrome in a case of atypical chronic lymphocytic leukaemia with the t(11;14)(q13;q32): role for a p53 exon 7 gene mutation. Cuneo A, de Angeli C, Roberti MG, Piva N, Bigoni R, Gandini D, Rigolin GM, Moretti S, Cavazzini P, del Senno L, Castoldi G. Institute of Haematology, University of Ferrara, Italy. Clinicobiological, histological, cytogenetic and molecular genetic studies were performed in a case of atypical B-cell chronic lymphocytic leukaemia (B-CLL) with the t(11;14)(q13;q32) evolving into Richter's syndrome (RS) in order (a) to determine the clonal relationship between the cell of origin for B-CLL and RS, and (b) to analyse genetic events underlying the disease progression in this patient. After 4 years following diagnosis, a rapid deterioration of the clinical picture occurred, concomitant with the appearance of large lymphoid blasts in peripheral blood (PB), bone marrow (BM) and ascites samples. A diagnosis of RS was made and cytogenetic analysis revealed karyotype evolution with trisomy 7 and del(17p) in addition to t(11;14). Fluorescence in situ hybridization showed 78% lymphoid blast cells obtained from ascites sample to be trisomic using a chromosome-7-specific pericentromeric probe. Whereas no rearrangement of the c-myc proto-oncogene was detected at disease progression, direct sequencing of p53 gene exon 5-9 revealed an exon 7 missense point mutation. This abnormality was not present in the CLL phase. Immunological staining with the monoclonal antibody PAb-1801, detecting the p53 protein product, revealed a negative pattern in the CLL phase, whereas 24% positivity was documented in representative samples obtained at RS. It is concluded that RS was cytogenetically related with B-CLL in this patient, suggesting the occurrence of a bona fide transformation and that the mutation of p53 exon 7, in association with the development of 17p deletion, possibly played a role in the development of RS. Publication Types: Case Reports PMID: 8603003 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 857: Laryngoscope. 1996 Feb;106(2 Pt 1):190-5. Expression of growth factors, proto-oncogenes, and p53 in nasopharyngeal angiofibromas. Nagai MA, Butugan O, Logullo A, Brentani MM. Departmento de Radiologia, Faculdade de Medicina, Universidade de Sao Paulo, Brazil. Biopsies from 25 juvenile nasopharyngeal angiofibromas (JNAs) and respective normal inferior turbinates were examined and compared. The expression patterns of the messenger RNAs (mRNAs) for various growth factors possibly involved in the growth of mesenchymal cells, as well as angiogenesis and fibrosis, were also compared. These growth factors included insulin-like growth factor II (IGF-II), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), transforming growth factors-beta1 (TGF-beta1) and platelet-derived growth factors (PDGF-A and PDGF-B). Quantification of mRNA coding for proto-oncogenes and suppressor genes related to proliferation (i.e., c-myc, c-fos, p53) was also undertaken. Tumor and turbinates expressed similar levels of bFGF, VEGF, TGF-beta1, c-myc, c-fos, and PDGF-A mRNAs. The presence of TGF-beta1 protein was confirmed by immunohistochemistry in several structures that characterize the lesions of JNA, which suggests that TGF-beta1 may play a role in the development of the fibrous component of this tumor. PDGF-B and p53 were overexpressed (i.e., twice the mean level found in turbinates) in 50% and 32% of JNAs, respectively but there was no statistical significance when compared with controls. Statistically significant increased expression of IGF-II mRNA was observed in JNA (P = .04). IGF-II mRNA levels were correlated to p53 (P = .05) and PDGF-B (P = .034), indicating a possible synergistic action of such factors in JNA. The results of this study suggest that IGF-II might be a potential growth regulator of nasopharyngeal angiofibromas. PMID: 8583852 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 858: Exp Cell Res. 1996 Jan 10;222(1):95-102. Comparison of apoptosis signaling through T cell receptor, fas, and calcium ionophore. Maecker HT, Hedjbeli S, Alzona M, Le PT. Department of Medicine/Oncology, Stanford University Medical Center, California 94305, USA. The SUP-T13 cell line, a human T leukemia, is susceptible to apoptosis by various inducers, including anti-TCR mAb, calcium ionophores, and anti-fas mAb. Induction of apoptosis by these three agents was investigated, and several differences were found. All three agents induced DNA fragmentation with a similar time course, but the kinetics of cell death were different for the three agents. Anti-TCR mAb-induced apoptosis, but not A23187- or anti-fas-induced apoptosis, was rescued by anti-CD3 mAb treatment. In contrast, only anti-fas mAb-mediated apoptosis was rescued by PKC activators such as PMA. These differences suggest that each of these three agents mediate apoptosis by unique signaling pathways. Nevertheless, two variant subclones of SUP-T13 were found to be resistant to all three apoptosis-inducing agents, suggesting a point(s) of common regulation between the different pathways. To determine whether this regulation occurred through bcl-2, p53, or c-myc, their expression in the parental and variant cells was determined. The three clones expressed approximately equal amounts of these proteins, and their levels did not change significantly upon treatment with anti-TCR or anti-TCR plus anti-CD3 mAb. Thus, although the proximal signaling by various apoptosis inducers were quite different, a common mediator(s) (as yet unknown) may still regulate apoptosis induced by these multiple agents. PMID: 8549678 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 859: Nature. 1996 Jan 4;379(6560):88-91. Comment in: Nature. 1996 Jan 4;379(6560):19-20. Nature. 1996 Mar 14;380(6570):100. Hypoxia-mediated selection of cells with diminished apoptotic potential in solid tumours. Graeber TG, Osmanian C, Jacks T, Housman DE, Koch CJ, Lowe SW, Giaccia AJ. Department of Radiation Oncology, Stanford University School of Medicine, California 94305, USA. Apoptosis is a genetically encoded programme of cell death that can be activated under physiological conditions and may be an important safeguard against tumour development. Regions of low oxygen (hypoxia) and necrosis are common features of solid tumours. Here we report that hypoxia induces apoptosis in oncogenically transformed cells and that further genetic alterations, such as loss of the p53 tumour-suppressor gene or overexpression of the apoptosis-inhibitor protein Bcl-2, substantially reduce hypoxia-induced cell death. Hypoxia also selects for cells with defects in apoptosis, because small numbers of transformed cells lacking p53 overtake similar cells expressing wild-type p53 when treated with hypoxia. Furthermore, highly apoptotic regions strongly correlate with hypoxic regions in transplanted tumours expressing wild-type p53, whereas little apoptosis occurs in hypoxic regions of p53-deficient tumours. We propose that hypoxia provides a physiological selective pressure in tumours for the expansion of variants that have lost their apoptotic potential, and in particular for cells acquiring p53 mutations. PMID: 8538748 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 860: Curr Top Microbiol Immunol. 1996;213 ( Pt 2):197-213. Alterations in cell cycle control during tumor progression: effects on apoptosis and the response to therapeutic agents. Muschel RJ, McKenna WG. Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia 19104-6082, USA. Publication Types: Review PMID: 9053291 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 861: Eisei Shikenjo Hokoku. 1996;(114):1-12. [The use of biotechnological recombinant-mice in biological safety research] [Article in Japanese] Inoue T. Number of transgenic and knock-out mice increased rapidly during the last decade. This review article describes a potential usefulness of transgenic and knock-out mice for biological safety research with respect to each toxicological category for safety evaluations, such as studies for carcinogenicity, general toxicology, genotoxicologic testing, and immuno-toxicological evaluations. In the carcinogenicity, a possible model required for a short-term study in carcinogenicity was discussed. Further, a couple of future subjects were focused specifically on the biotechnology-derived pharmaceuticals and the biotechnical recombinant-mice as a second generation, i.e. experimental mice with double or multiple gene-recombination. Those usefulnesses were also introduced briefly. Establishing the biotechnical recombinant-mice for each safety testing contributes not only to simplify and qualify the on-going evaluation system, but also to the traditional animal studies to be re-evaluated, so that the solutions may lead them to a future in vitro-alternative system much smoothly. For general references, historical reviews on the biotechnical recombination in experimental animals were also briefly introduced to elucidate a new broad area in developmental biology. Publication Types: Review Review, Tutorial PMID: 9037857 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 862: Cancer Detect Prev. 1996;20(1):20-30. A possible role for human papillomaviruses and c-myc, c-Ha-ras, and p53 gene alterations in malignant cutaneous lesions from renal transplant recipients. Pelisson I, Soler C, Chardonnet Y, Euvrard S, Schmitt D. Edouard Herriot Hospital, Lyon, France. Several years after transplantation, renal transplant recipients develop numerous cutaneous squamous cell carcinomas (SCC), in which human papillomaviruses (HPV) may be detected. Alterations in c-myc, c-Ha-ras, and p53 genes were studied in 34 SCC, in correlation with the presence of HPV. In situ hybridization (ISH) and polymerase chain reaction (PCR) showed that many SCC contained several HPV types infecting different foci of epithelial cells. Using Southern blot and ISH, c-myc and/or c-Ha-ras gene amplification was detected in 7/13 SCC tested. With PCR and oligoprobe hybridization, a GGC -> GAC mutation was found at codon 12 of c-Ha-ras gene in 1/21 SCC tested, while no mutation was detected at codon 61. Using immunohistochemistry, p53 protein expression was detected either along the basal cell layer or spotted in foci of basal cells. Our results show an abnormal distribution of HPV types in SCC from renal transplant recipients, and alterations of c-myc, c-Ha-ras, and p53 genes without any direct link with the presence of any studied HPV type. Thus, viral infection and oncogene activation may represent factors involved in the etiology of skin SCC from transplant recipients. PMID: 8907200 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 863: Clin Oncol (R Coll Radiol). 1996;8(3):186-9. The interaction of oncogene and tumour suppressor gene defects with cytotoxic drugs: its role in the improvement of selective toxicity and the development of new drugs in clinical oncology. Petty RD. Ninewells Hospital and Medical School, Dundee, UK. Publication Types: Review Review, Tutorial PMID: 8814375 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 864: Brain Res Mol Brain Res. 1996 Jan;35(1-2):19-30. Gamma-radiation-induced cell death in the fetal rat brain possesses molecular characteristics of apoptosis and is associated with specific messenger RNA elevations. Borovitskaya AE, Evtushenko VI, Sabol SL. Laboratory of Biochemical Genetics, National Heart, Lung, and Blood Institute, Bethesda, MD 20892, USA. Low-dose ionizing irradiation of 16-18-day pregnant rats rapidly kills stem cells in the fetal forebrain. We have examined gamma-irradiated 17-day fetal rat brain tissue for molecular characteristics of apoptosis and changes in levels of mRNAs relevant to apoptosis. In many forebrain cells radiation elicits within 5 h nuclear condensation and fragmentation consistent with apoptosis. An electrophoretic DNA ladder indicative of internucleosomal chromatin cleavage was prominent within 3 h after irradiation. Pretreatment of pregnant rats with cycloheximide, or pretreatment of dissociated fetal brain cells in culture with actinomycin D, abolished the radiation-induced internucleosomal DNA fragmentation, demonstrating requirements for protein and RNA synthesis. Irradiation dramatically increased the level of the p53 transcription factor and the abundances of mRNAs coding for the cell-cycle inhibitor p21/Waf-1/Cip-1 and the AP-1-associated transcription factors Fos and JunB. Irradiation moderately increased the level of mRNA for the positive apoptosis regulator Bax. In contrast, irradiation reduced by 50-70% the abundances of most other mRNAs tested, including those for housekeeping proteins, p53, Jun, Myc, interleukin-1-beta-converting enzyme, and the negative apoptosis regulators Bcl-2 and Bcl-xL. These results indicate that radiation-elicited apoptosis of fetal brain cells is associated with activation of the p53 system, probable increases in AP-1 Fos/JunB heterodimers, and an increased ratio of Bax to Bcl-2 + Bcl-xL. PMID: 8717336 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 865: Oncogene. 1995 Dec 21;11(12):2609-18. Overexpression of human p21waf1/cip1 arrests the growth of chicken embryo fibroblasts transformed by individual oncogenes. Givol I, Givol D, Rulong S, Resau J, Tsarfaty I, Hughes SH. ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Maryland 21702-1201, USA. In normal cells, cell growth and division is controlled by the interplay between proto-oncogenes and tumor suppressor genes. Cancer cells usually have both activated an oncogene and have lost a functional tumor suppressor gene. High level expression of a tumor suppressor, p53, can block the growth of cancer cells. waf1/cip1 is transactivated by the tumor suppressor p53 and the p21waf1/cip1 protein is itself a suppressor of cell growth. To test the effect of growth suppression genes on the growth of cells transformed by individual oncogenes, we have used replication-competent retroviral vectors to induce high level expression of p53 and p21waf1/cip1. Overexpression of p21waf1/cip1 arrests the growth of chicken embryo fibroblasts (CEF) transformed by v-Src, tf-Ras, c-Mos and c-Myc. These data suggest that p21waf1/cip1 might be a useful tool in gene therapy for human cancer. PMID: 8545118 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 866: FEBS Lett. 1995 Dec 11;377(1):51-3. Fibroblasts transformed by combinations of ras, myc and mutant p53 exhibit increased phosphorylation of histone H1 that is independent of metastatic potential. Taylor WR, Chadee DN, Allis CD, Wright JA, Davie JR. Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Canada. H1 histones play an important role in regulating higher order structure of chromatin and are potential regulators of gene expression. H1s are phosphorylated, a modification which alters their interaction with DNA. We measured the abundance of three phosphorylated H1 subtypes in mouse fibroblasts transformed by combinations of ras, myc and mutant p53 which differ in metastatic potential. We found that there is an increase in phosphorylation of H1 subtypes in fibroblasts transformed with ras, myc and mutant p53. This increase was found to correlate with cellular transformation but not with induction of the metastatic phenotype. PMID: 8543017 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 867: Oncogene. 1995 Dec 7;11(11):2411-8. c-Myc induces apoptosis in epithelial cells by both p53-dependent and p53-independent mechanisms. Sakamuro D, Eviner V, Elliott KJ, Showe L, White E, Prendergast GC. Wistar Institute, Philadelphia, Pennsylvania 19104, USA. We tested the hypothesis that wild-type p53 activity is required for c-Myc-dependent apoptosis in epithelial cells. Primary baby rat kidney epithelial cell lines were generated by immortalization through the concerted action of c-Myc and a temperature-sensitive (ts) dominant inhibitory mutant allele of p53 (BRK myc/p53ts cells). When shifted to the permissive temperature for wild-type p53 activity, the BRK myc/p53ts cells underwent growth arrest and apoptosis. However, apoptosis also could be induced by serum deprivation at the nonpermissive temperature, when p53 was in the mutant state. Bcl-2 suppressed both modes of cell death. Apoptosis induced by wild-type p53 but not by serum deprivation was accompanied by G1 cell cycle arrest and increased expression of the Bcl-2 antagonist Bax. We concluded that c-Myc could induce apoptosis in epithelial cells by at least two mechanisms that could be distinguished by their p53 requirement. Our results support the possibility that c-Myc-dependent cell death might be exploited for therapeutic ends during carcinoma development, without regard to p53 status of the target cell. PMID: 8570193 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 868: Nihon Kyobu Shikkan Gakkai Zasshi. 1995 Dec;33(12):1348-54. [Positive expression of c-myc and p53 products in two cases of pulmonary sclerosing hemangioma] [Article in Japanese] Chiba W, Sawai S, Yasuda Y, Wazawa H, Matsubara Y, Ikeda S. Respiratory Disease Center, Kyoto Katsura Hospital, Japan. The c-myc and p53 genes are thought to be an oncogene and a tumor suppressor gene, respectively. These genes' products are characteristic of malignant tumors. We quantitatively analyzed the c-myc and p53 products by flow cytometry in two cases of pulmonary sclerosing hemangioma. In case 1, 32.3% of the tumor cells were found to have the c-myc product, and 8.9% were found to have the p53 product. In case 2, 6.7% of the tumor cells were found to have the c-myc product and 15.5% were found to have the p53 product. The percentages in both cases were twice as high as those in a negative control lymphocytes stained with c-myc and p53 products. Therefore, these two cases showed positive expression of the c-myc and p53 products. In addition DNA from six other patients with sclerosing hemangioma was analyzed with paraffin-embedded sections. All six had DNA diploidy, with DNA indexes ranging from 0.91 to 1.03 and coefficients of variation ranging from 3.0 to 5.5. We suggest that pulmonary sclerosing hemangioma is a very weakly malignant tumor. PMID: 8821986 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 869: Ann Thorac Surg. 1995 Dec;60(6):1583-91. c-myc antisense oligodeoxyribonucleotides inhibit proliferation of non-small cell lung cancer. Robinson LA, Smith LJ, Fontaine MP, Kay HD, Mountjoy CP, Pirruccello SJ. Division of Cardiovascular and Thoracic Surgery, University of South Florida, H. Lee Moffitt Cancer Center and Research Institute, Tampa 33612-9497, USA. BACKGROUND: Mutation or deregulation of certain cellular genes (protooncogenes) results in expression of proteins that appear to promote malignant transformation. Human non-small cell lung cancer has been documented to express many such oncogenes including c-myc, bcl-2, and mutant p53. Antisense oligodeoxyribonucleotides (ASODN) complementary to these oncogenes were tested on three non-small cell lung cancer cell lines for their efficacy in inhibiting cellular proliferation and oncoprotein expression. METHODS: Established non-small cell lung cancer cell lines A427, SKMES-1, and A549 were grown in the presence of ASODNs complementary to messenger RNA of c-myc, bcl-2, p53, or controls at 1 mumol/L or 10 mumol/L concentrations for 4 or 10 days. Cellular proliferation was measured by tritiated thymidine uptake. Flow cytometry was used to quantitate oncoprotein expression. Intranuclear ASODN uptake was documented by fluoresceine-tagged ASODNs. RESULTS: Fluoresceine-tagged ASODNs were readily taken up by all cell lines. c-myc, as well as bcl-2 and p53 ASODNs, were found to inhibit proliferation of all cell lines significantly compared with controls, most notably in line A549 (40.1% +/- 7.1% of control, p = 0.000 with c-myc ASODN). Antisense c-myc reduced c-myc protein by as much as 71.3% in A427, although protein levels were only minimally reduced in the viable cells of the other lines. CONCLUSIONS: c-myc ASODNs inhibit proliferation of non-small cell lung cancer cell lines as well as reduce c-myc protein expression. Antisense bcl-2 and p53 also cause similar growth inhibition. These results suggest a critical role for activation of these oncogenes in the growth of cultured lung cancer cells. Furthermore, the efficacy and rapid cellular uptake of ASODNs support the potential role of antisense targeting of oncogene expression for pharmacologic control of non-small cell lung cancer. PMID: 8787447 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 870: Ann Oncol. 1995 Dec;6(10):981-6. Evidence for a mutual regulation of p53 and c-myc expression in human colorectal cancer metastases. Rochlitz CF, Heide I, Thiede C, Herrmann R, de Kant E. Department Innere Medizin, Abteilung fur Onkologie, Kantonsspital Basel, Switzerland. BACKGROUND: Alterations of the c-myc and the p53 genes occur in a majority of human colorectal cancers, and functional interaction between these two genes has recently been suggested. PATIENTS AND METHODS: We analyzed p53 sequence and c-myc and p53 mRNA expression in 26 metastases and 4 advanced primaries of human colorectal cancer. RESULTS: Twenty-one of 30 tumors (=70%) carried mutations of the p53 gene. In these samples, c-myc and p53 were overexpressed in 70% (15/21) and 71% (14/20) of evaluable cases, respectively, while in tumors carrying only wild-type p53, overexpression of c-myc and p53 was observed in only 33% (3/9; p < 0.05) and 22% (2/9; p < 0.01), respectively. Expression of p53 and c-myc were positively correlated (p = 0.014; r = 0.563) in tumors carrying a p53 mutation, but not in those with only wild-type p53. CONCLUSION: We conclude that c-myc might induce p53 expression in human colorectal cancer and that wild-type but not mutant p53 might be involved in a negative feedback regulation of c-myc expression. The abrogation of this normal control mechanism seems to be an essential step during colorectal tumorigenesis and metastatic progression. PMID: 8750149 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 871: Ann Oncol. 1995 Dec;6(10):961-2. p53, myc, APC, hMSH2, ras, etc. in colorectal cancer - a never ending story! Fey MF. Publication Types: Editorial PMID: 8750144 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 872: Genes Chromosomes Cancer. 1995 Dec;14(4):227-51. Genetic alterations in breast cancer. Bieche I, Lidereau R. Laboratoire d'Oncogenetique, Centre Rene Huguenin, St.-Cloud, France. The etiology of breast cancer involves a complex interplay of various factors, including genetic alterations. Many studies have been devoted to the identification and characterization of mutations that occur frequently during breast tumorigenesis. The major types of genetic abnormalities that are frequently observed in breast tumors are amplification of protooncogenes (MYC, ERBB2) and DNA from chromosome band 11q13; mutation of TP53; and loss of heterozygosity from chromosomes and chromosome arms 1, 3p, 6q, 7q, 8p, 11, 13q, 16q, 17, 18q, and 22q. The latter may correspond to losses or inactivations of tumor suppressor genes. Recently, linkage analyses of large families with a predisposition to breast cancer have been performed in order to map breast cancer susceptibility genes (TP53, BRCA1, BRCA2). The findings have thrown light on the molecular mechanisms of breast cancer and have enabled various genetic markers to be used in clinical oncology. Publication Types: Review PMID: 8605112 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 873: J Pathol. 1995 Dec;177(4):395-400. Multiple genetic alterations in malignant metastatic insulinomas. Pavelic K, Hrascan R, Kapitanovic S, Karapandza N, Vranes Z, Belicza M, Kruslin B, Cabrijan T. Department of Molecular Medicine, Ruder Boskovic Institute, Zagreb, Croatia. Proto-oncogenes, growth factors/receptors, and tumour suppressor genes were analysed in malignant metastatic insulinomas. Normal pancreas showed only a moderate immunoreaction for c-myc proto-oncogene and a strong reaction for insulin. Benign insulinomas were slightly or moderately positive for transforming growth factor alpha (TGF alpha), weakly positive for epidermal growth factor receptor (EGF-R), and strongly positive for c-myc and insulin. In malignant insulinomas, besides a strong immunoreaction for c-myc and TGF alpha, activation of c-K-ras and overexpression of p53 protein were found. Insulin reaction was moderate or strong. Three out of six malignant insulinomas displayed a c-K-ras point mutation at codon 12. All mutations were guanine to cytosine transversion, resulting in amino acid substitution, glycine to arginine. Mutations were present in metastatic insulinomas only. Patients with mutated c-K-ras oncogene had overexpression of p53 protein as well as c-myc and TGF alpha overexpression. Our results support the view that malignant progression is a consequence of more than one genetic lesion and suggest that activation of myc, TGF alpha an ras genes plays a role in a multistep process of tumour progression, perhaps serving as an initiating event. PMID: 8568594 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 874: J Biol Chem. 1995 Dec 1;270(48):28503-6. Transcriptional repression of p53 by human T-cell leukemia virus type I Tax protein. Uittenbogaard MN, Giebler HA, Reisman D, Nyborg JK. Department of Microbiology, Colorado State University, Fort Collins 80523, USA. The human T-cell leukemia virus type I oncoprotein Tax transcriptionally deregulates a wide variety of viral and cellular genes. Tax deregulation of gene expression is mediated through interaction with a variety of structurally unrelated cellular transcription factors, as Tax does not bind DNA in a sequence-specific manner. Although most of these cellular transcription factors have been shown to mediate activation by Tax, we have recently demonstrated that members of the basic helix-loop-helix (bHLH) family of transcription factors, which play a critical role in progression through the cell cycle, mediate repression by Tax. In this report, we examined whether Tax might repress transcription of the tumor suppressor p53, as the p53 gene has recently been demonstrated to be regulated by the bHLH protein c-Myc. Furthermore, loss or inactivation of the p53 gene has been shown to be causally associated with oncogenic transformation. We show that Tax represses transcription of the p53 gene and that this repression is dependent upon the bHLH recognition element in the p53 promoter. Together, these results suggest that Tax may promote malignant transformation through repression of p53 transcription. PMID: 7499359 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 875: Cancer. 1995 Nov 15;76(10 Suppl):2034-40. Molecular basis of endometrial cancer. Berchuck A, Boyd J. Department of Obstetrics and Gynecology/Division of Gynecologic Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA. BACKGROUND. Most human cancers are thought to arise from alterations in oncogenes and tumor suppressor genes. METHODS. Molecular techniques have been used to identify specific genetic alterations in endometrial cancers. RESULTS. Overexpression of the HER-2/neu oncogene occurs in 10% of endometrial cancers and correlates with poor survival. Alterations in other receptor tyrosine kinases (c-fms and epidermal growth factor receptor) also occur in some cases. The c-myc oncogene, which encodes a nuclear transcription factor, also may be overexpressed in some invasive cancers. Mutations in the K-ras oncogene occur in 10% and in 20-30% of American and Japanese endometrial cancers, respectively. K-ras mutations also have been observed in endometrial hyperplasias, and this may represent an early event in the development of some cancers. Mutation of the p53 tumor suppressor gene, with resultant overexpression of mutant p53 protein, occurs in 20% of endometrial adenocarcinomas. Overexpression of p53 is associated with advanced stage and poor survival. Because p53 mutations do not occur frequently in endometrial hyperplasias, this may be a relatively late event in endometrial carcinogenesis. Recent studies have shown that mutations occur in microsatellite sequences in some endometrial cancers. Because microsatellite instability in hereditary nonpolyposis colon cancer has been found to be caused by mutations in DNA repair genes, similar mutations are being sought in endometrial cancers. CONCLUSIONS. Although several molecular alterations have been identified, the molecular pathogenesis of endometrial cancer remains poorly understood. Publication Types: Review Review, Tutorial PMID: 8634996 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 876: Cancer Res. 1995 Nov 15;55(22):5207-12. Radiation-induced apoptosis: effects of cell age and dose fractionation. Ling CC, Guo M, Chen CH, Deloherey T. Laboratory of Radiation Biophysics, Memorial Sloan Kettering Cancer Center, New York, New York 10021, USA. The cell cycle dependence of radiation-induced apoptosis was measured using mitotically synchronized REC:myc(ch1) and Rat1:mycb cells. Cells in S and G2 phases were more susceptible; the apoptotic fraction was about 0.7-0.8 as compared to about 0.4 for G1 cells at a dose of 10 Gy. Two-dimensional cytofluorimetric analysis of cells, pulsed-labeled with bromodeoxyuridine and then irradiated with 10 Gy, showed both G1 and G2 blocks (6-8 h) for REC:myc(ch1) cells but only G2 block for Rat1:mycb cells. Consistent with these results, wild-type p53 and WAF1 (or p21), known to play a role in G1 delay, was induced by radiation in REC:myc(ch1) but not in Rat1:mycb cells. The cell cycle dependence of radiation-induced apoptosis and the absence of a G1 block for Rat1:mycb cells led to the prediction and observation of the novel "inverse split-dose effect," i.e., a radiation dose given in two equal halves separated by a few hours yielded a higher level of apoptosis relative to that resulting from the same total dose given all at once. This effect is due to cell cycle progression from G1 to the more sensitive S-G2 phase during the interval between the split doses. In contrast, the inverse split-dose effect for apoptosis is absent for REC:myc(ch1), due presumably to the radiation-induced G1 delay. Parallel split-dose experiments, but using clonogenic survival as end points, show recovery for REC:myc(ch1) cells but not for Rat1:mycb cells, reflecting the influence of split-dose, radiation-induced apoptosis. PMID: 7585576 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 877: Cancer Lett. 1995 Nov 6;97(2):169-75. Modulation of expression of genes encoding nuclear proteins following exposure to JANUS neutrons or gamma-rays. Woloschak GE, Chang-Liu CM. Center for Mechanistic Biology and Biotechnology, Argonne National Laboratory, IL 60439-4833, USA. Previous work has shown that exposure of cells to ionizing radiations causes modulation of a variety of genes, including those encoding c-fos, interleukin-1, tumor necrosis factor, cytoskeletal elements, and many more. The experiments reported herein were designed to examine the effects of either JANUS neutron or gamma-ray exposure on expression of genes encoding nucleus-associated proteins (H4-histone, c-jun, c-myc, Rb, and p53). Cycling Syrian hamster embryo cells were irradiated with varying doses and dose rates of either JANUS fission-spectrum neutrons or gamma-rays; after incubation of the cell cultures for 1 h following radiation exposure, mRNA was harvested and analyzed by Northern blot. Results revealed induction of transcripts for c-jun, H4-histone, and (to a lesser extent) Rb following gamma-ray but not following neutron exposure. Interestingly, expression of c-myc was repressed following gamma-ray but not following neutron exposure. Radiations at different doses and dose rates were compared for each of the genes studied. PMID: 7497459 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 878: Eur J Cancer B Oral Oncol. 1995 Nov;31B(6):384-91. Differential c-myc, c-jun, c-raf and p53 expression in squamous cell carcinoma of the head and neck: implication in drug and radioresistance. Riva C, Lavieille JP, Reyt E, Brambilla E, Lunardi J, Brambilla C. Lung and Airways Cancer Research Group, Albert Bonniot Institute, La Tronche, France. The expression of oncogenes c-myc, c-jun and c-raf and tumour suppressor gene p53 was assessed by northern blot analysis of 42 tumours and p53 protein expression by immunohistochemistry on paraffin-embedded sections from 36 specimens of squamous cell carcinoma of the head and neck (SCCHN) obtained before therapy. Of the 42 tumours, 89, 100 and 100% expressed c-myc, c-jun and c-raf oncogenes, respectively. These oncogene expressions did not correlate with sex, age or clinical stage of the disease. However, an association was found between low c-myc expression (P = 0.0001) and high c-jun expression (P = 0.0001) and absence of tumoral response to neoadjuvant chemotherapy. On the other hand, c-raf overexpression was observed in patients resistant to radiation therapy (P = 0.0494). Forty-two per cent of the tumours showed p53 protein overexpression, which did not correlate with any clinical parameter. This p53 protein overexpression was associated with high p53 mRNA levels (REL) (P = 0.0223). A correlation was found between increased c-myc RNA expression and lack of p53 protein expression (P = 0.0407). In addition, a lack of p53 protein expression was indicative of tumour relapse (P = 0.05). None of these biological parameters were associated with disease-free survival (Cox-Mantel test). In conclusion, the overexpression of c-myc, c-jun and c-raf may be independently associated to tumoral response to chemotherapy or radiotherapy, or to tumour relapse, but fail to predict long-term survival. PMID: 8746269 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 879: Zhonghua Zhong Liu Za Zhi. 1995 Nov;17(6):432-4. [Expression of oncogene and anti-oncogene in mouse lung cancer induced by coal-burning smoke] [Article in Chinese] Lin C, Dai X, Sun X. Cancer Research Institute, Harbin Medical University. Previous epidemiology studies have shown association between coal burning and human lung cancer. To confirm relationship of coal burning to lung cancer formation and progression the expression of p53 and c-myc in 13 mouse lung cancer induced by coal-burning smoke and 5 mouse lung tissue control was studied by DNA-RNA in situ hybridization (ISH). Nine of 13 specimens showed c-myc overexpression but it occurred only 1 in 9 in the adjacent tissue. There was overexpression of p53 mRNA in all 13 lung cancer and 5 adjacent tissues. None in the controls was expression of p53 and c-myc detected. When compared to controls, there was significant higher expression of c-myc gene (P = 0.002) and p53 gene (P = 0.0001). The results confirm that overexpression of p53 and c-myc are common molecular events of lung cancer by coal-burning smoke and provide further evidence that smoke from coal burning is a causative agent of lung cancer. PMID: 8697995 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 880: Zhonghua Zhong Liu Za Zhi. 1995 Nov;17(6):415-7. [Overexpression of c-myc and p53 gene in human hepato-cellular carcinoma--a study with immunohistochemistry and in situ hybridization] [Article in Chinese] Yang S, Wang M, You W. PLA General Hospital, Beijing. Immunohistochemistry (ABC method) and in situ hybridization (DNA-RNA) were used to detect c-myc and p53 gene expression in tissues of human HCC and nearby non-tumorous liver (NT) from 23 patients. The results showed that the positive rates of P62c-myc were 87% (20/23) in HCC and 91% (21/23) in NT. The positive rates of P53 protein were 39% (9/23) in HCC as well as in NT. The positive rates of c-myc and p53 mRNA were 70% (16/23) and 56% (13/23) in HCC and NT respectively. The expression of c-myc and p53 at protein level was significantly correlated with that at mRNA level. These observations suggest a close association of c-myc and p53 gene overexpression with hepatocarcinogenesis. Immunohistochemistry (ABC method) on section of paraffin embedded tissue is a reliable method for detecting c-myc and p53 gene expression in HCC. PMID: 8697990 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 881: Zhonghua Yi Xue Za Zhi. 1995 Nov;75(11):676-8, 710. [Reversing effect of dimethyl-4,4'-dimethoxy-5,6,5'6'-dimethylenedioxybiphenyl-2,2'- dicarboxylate(DDB) on the phenotypes of human hepatocarcinoma cell line] [Article in Chinese] Liu Z, Liu G, Zhang S. Department II of Pharmacology, Chinese Academy of Medical Sciences, Beijing. When human Bel-7402 hepatocarcinoma cell line grew in a medium containing 10(-4)M DDB, the secretion of alpha-fetoprotein (AFP) and the activity of gamma-glutamyl-transpeptidase (gamma-GT) were significantly lower than the control cells, whereas the albumin (ALB) secretion and the activity of tyrosine-alpha-ketoglutarate transaminase (TAT) were markedly increased. DDB at the concentration of 10(-4)M could significantly increase the content of cAMP in Bel-7402 cells, and also suppressed the expressions of oncogene c-myc and hepatocarcinoma marker AFP gene and enhanced the anti-oncogene p53 expression. The results of this paper suggest that DDB has some reversing effects on the phenotypes of human Bel-7402 hepatocarcinoma cell line. PMID: 8697089 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 882: Biotechniques. 1995 Nov;19(5):706-8, 710. Validation of northern blot analysis for quantitating the expression of several genes in rat liver. Triest S, Maiter D, Ketelslegers JM. University of Louvain School of Medicine, Brussels, Belgium. PMID: 8588900 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 883: Blood. 1995 Oct 15;86(8):3160-72. Molecular analysis of cutaneous B- and T-cell lymphomas. Neri A, Fracchiolla NS, Roscetti E, Garatti S, Trecca D, Boletini A, Perletti L, Baldini L, Maiolo AT, Berti E. Laboratorio di Ematologia Sperimentale e Genetica Molecolare, Universita di Milano, Ospedale Maggiore, IRCCS, Italy. Among extranodal non-Hodgkin's lymphomas, primary cutaneous lymphomas (CLs) represent a consistent group of B- and T-cell malignancies. We investigated the arrangement of Ig and T-cell receptor (TCR) genes, together with the involvement of several oncogenes and the tumor-suppressor gene p53, in a panel of primary cutaneous B- and T-cell lymphomas (CBCLs and CTCLs). Southern blot analysis was performed to detect rearrangements of the Ig, c-myc, bcl-1, bcl-2, bcl-3, bcl-6, and the NFKB2/lyt-10 genes in 52 cases of CBCLs and of the TCR, bcl-3, and NFKB2/lyt-10 genes in 38 cases of CTCLs. tal-1 gene deletions were analyzed in CTCLs by means of polymerase chain reaction (PCR). p53 gene mutations were assayed using PCR, single-strand conformation polymorphism analysis, and direct DNA sequencing in CBCL and CTCL cases. Clonal rearrangements of Ig genes or oncogenes were found in 25 of the 52 CBCLs. In particular, we detected rearrangements of the bcl-1 locus (2 cases), the bcl-2 gene (2 cases), the NFKB2/lyt-10 gene (2 cases), and the bcl-6 gene (1 case); interestingly, 4 of these cases showed a germline arrangement of the Ig genes. Clonal rearrangements of TCR genes were detected in 37 of the 38 CTCLs. Rearrangements of the NFKB2/lyt-10 gene were present in 2 cases and tal-1 gene deletions in 3 CTCL cases; p53 gene mutations were detected in 1 CTCL case. Overall, our data indicate that (1) clonal rearrangement of Ig genes is frequently undetectable by means of Southern blot in CBCLs (60%); (2) genetic lesions are involved in a limited but significant fraction of primary CLs showing a molecular marker of clonality (13/62; 20%); and (3) rearrangements of the bcl-1, bcl-2, or bcl-6 loci, associated with specific subsets of nodal lymphoid neoplasias, are rarely observed in CBCLs. Moreover, our results suggest that tal-1 gene deletions may play a pathogenetic role in non-acute T-cell malignancies and that, in the context of lymphoid malignancies, CLs may represent a favorable target for the possible oncogenic potential of the NFKB2/lyt-10 gene. PMID: 7579411 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 884: Proc Natl Acad Sci U S A. 1995 Oct 10;92(21):9672-6. A mutant p53 antagonizes the deregulated c-myc-mediated enhancement of apoptosis and decrease in leukemogenicity. Lotem J, Sachs L. Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel. Myeloid leukemic M1 cells that do not express p53 and transfected M1 clones that constitutively express the [Val135]p53 mutant or deregulated c-myc or coexpressing both genes grew autonomously in culture with a similar growth rate and cloning efficiency. Expression of deregulated c-myc in M1 leukemic cells enhanced susceptibility to induction of apoptotic cell death and resulted in a reduced leukemogenicity when injected into isologous mice. Expression of the [Val135]p53 mutant did not change cell susceptibility to induction of apoptosis or leukemogenicity, but expression of this mutant p53 suppressed the effects of deregulated c-myc on these properties. The results indicate that the [Val135]p53 mutant can show a gain of function for susceptibility to apoptosis and leukemogenicity in leukemic cells with deregulated c-myc and, thus, enhance tumor development. PMID: 7568195 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 885: Oncogene. 1995 Oct 5;11(7):1409-15. Abrogation of p53-induced cell cycle arrest by c-Myc: evidence for an inhibitor of p21WAF1/CIP1/SDI1. Hermeking H, Funk JO, Reichert M, Ellwart JW, Eick D. Institut fur Klinische Molekularbiologie und Tumorgenetik, GSF-Forschungszentrum fur Umwelt und Gesundheit, Munchen, Germany. The tumor-suppressor p53 inhibits cell cycle progression by direct transactivation of the p21WAF1/CIP1/SDI1 gene, which encodes a universal inhibitor of cyclin dependent kinases (cdk). The proto-oncogene product c-Myc induces cell cycle progression and, in the absence of survival factors, apoptosis. However, a direct link between the cell cycle machinery and c-Myc has not yet been established. We show that c-Myc has not yet been established. We show that c-Myc abrogates a p53-induced G1-arrest without elevating the expression of cdks or cyclins involved in the G1/S-transition. Instead, the results suggest that c-Myc interferes with the inhibitory action of p21 on cdk/cyclin-complexes by inducing a heat-labile inhibitor of p21. The inactivation of p21 and related cdk-inhibitors may explain several of the oncogenic actions of c-Myc, including the induction of proliferation, immortalisation and the inhibition of differentiation. Modulation of cdk activity by the induction of an inhibitor of cdk-inhibitors represents a novel mechanism of cell cycle regulation in mammalian cells. PMID: 7478565 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 886: Rev Prat. 1995 Oct 1;45(15):1903-8. [Apoptosis and cancer] [Article in French] May P, May E, Schwartz L, Yonish-Rouach E. Laboratoire d'oncologie moleculaire, IRC-IFR du CNRS, Villejuif. Apoptosis is a mode of active cell death having distinct biochemical and morphological features including chromatin condensation, polynucleosomal DNA fragmentation, and disruption of cells into apoptotic bodies. The apoptotic process plays a major role both during development and in the functioning of the immune system. Apoptosis may in part be genetically regulated, and may also be linked to physiological and non physiological signals from the environment. Apoptosis may be a defense at the cellular level against cancer. Moreover, there is evidence that a number of pro-oncogenes and tumor suppressor genes are involved in regulating apoptosis. Further understanding of the molecular events underlying the apoptotic process should provide new insights into the mechanism of tumorigenesis and facilitate the development of new strategies for the treatment of cancer. PMID: 8525299 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 887: Cancer Res. 1995 Oct 1;55(19):4416-9. Benign breast disease: absence of genetic alterations at several loci implicated in breast cancer malignancy. Lizard-Nacol S, Lidereau R, Collin F, Arnal M, Hahnel L, Roignot P, Cuisenier J, Guerrin J. Laboratory of Molecular Genetics, Centre Georges Francois Leclerc, Dijon, France. Benign breast disease (BBD) is a heterogeneous group of benign breast problems that has been associated with breast cancer risk by several investigators. Genetic alterations have been described in breast carcinomas under the headings of loss of heterozygosity (1p, 3p, 7q, 11p, 17p, 17 and 18q), mutations (p53, c-H-ras-1), and/or gene amplifications (c-myc, int-2/FGF3, and c-erbB-2/neu). In an attempt to determine whether these genetic alterations might also be involved in the development of BBD, we have analyzed such alterations in 50 BBD lesions. The histological types of samples studied were: 37 fibroadenomas; 8 benign phyllode tumors; and 5 fibrocytic diseases. Cellular DNA was extracted from tissues and from corresponding blood leukocytes according to standard techniques, digested with appropriate restriction endonucleases, and analyzed by Southern blot. The following are informative cases found in a total number of patients analyzed for each locus: 13 of 26 for L-myc (1p); 9 of 23 for THRB (3p); 11 of 29 for met (7q); 27 of 50 for c-H-ras-1 (11p); 3 of 13 for TP53 (17p); 14 of 50 for D17S30 (17p); 20 of 33 for D17S4 (17q); and 13 of 33 for D18S5 (18q). No loss of heterozygosity was detected at any of the examined loci. Alternatively, none of the 50 BBD cases displayed an amplification of the three genes tested (c-myc, int-2/FGF3, and c-erbB-2/neu). Our results show that molecular alterations, which are more frequently involved in malignant breast carcinomas, do not occur in BBD lesions. These results indicate that these molecular alterations could constitute late events in the pathogenesis of breast carcinomas. PMID: 7671254 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 888: Gynecol Oncol. 1995 Oct;59(1):87-92. Combination anti-gene therapy targeting c-myc and p53 in ovarian cancer cell lines. Janicek MF, Sevin BU, Nguyen HN, Averette HE. Department of Gynecology and Obstetrics, University of Miami School of Medicine, Florida 33136, USA. Gene therapy clinical trials targeting p53 and other genes are underway in nongynecologic cancer systems. To explore the potential for antigene therapy in gynecologic oncology, we examined the in vitro effects of oligonucleotides targeting c-myc and p53 in the ovarian cancer cell lines CAOV-3, SKOV-3, and BG-1. The ATP cell viability assay was used to measure growth effects after 6-day treatments with 27-mer antisense phosphorothioate oligodeoxyribonucleotides (oligos) targeting the Puf/nm23 binding region of c-myc and promoter/ATG region of p53. A random sequence of the p53 27-mer was used as a control, and an untransformed fibroblast cell line was used for comparison. IC50 was defined as the oligo concentration required for 50% growth reduction compared to untreated controls. Synergistic vs antagonistic effects of oligo combinations were quantitated by combination indexes (CI) as calculated from median effect parameters by the methods of Chou and Talalay. Mean +/- SE IC50's of c-myc and p53 antisense oligos in CAOV-3 and SKOV-3 ranged from 1.0 +/- 0.2 to 9.7 +/- 1.3 microM. The IC50's of c-myc oligos were consistently lower than corresponding p53 oligos in all cell lines (P < 0.034, t test). The fibroblast cell line was sensitive to anti-c-myc and combination anti-c-myc/p53 oligos (IC50 = 1.5 +/- 0.6 and 1.4 +/- 0.2 microM, respectively), but not to anti-p53 oligos alone (IC50 > 16 microM). Nonspecific toxicity was observed at concentrations of 16 microM for all cell lines except in BG-1, where maximal growth stimulation occurred at this concentration with anti-p53 oligos. Growth stimulation was also observed in BG-1 with anti-c-myc and anti-c-myc/p53 combinations at intermediate doses, with inhibition at higher doses. While c-myc/p53 combinations in CAOV-3 were synergistic (CI < 0.8), they were antagonistic in SKOV-3 (CI > 3.2). Phosphorothioate oligos directed against c-myc and p53 in different cell lines were shown to have both antiproliferative and stimulatory activity, as single agents and in combination, at concentrations that are achievable in vivo. Because of the complex patterns of effects, further in vitro studies are warranted before considering clinical trials with these agents in gynecologic cancers. PMID: 7557622 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 889: Br J Cancer. 1995 Oct;72(4):922-7. Effects of transforming growth factor beta-1 on growth-regulatory genes in tumour-derived human oral keratinocytes. Paterson IC, Patel V, Sandy JR, Prime SS, Yeudall WA. Department of Oral and Dental Science, University of Bristol Dental Hospital and School, UK. This study examined the effect of transforming growth factor beta-1 (TGF-beta 1) on c-myc, RB1, junB and p53 expression together with pRb phosphorylation, in carcinoma-derived and normal human oral keratinocytes with a range of inhibitory responses to this ligand. Amplification of c-myc was observed in eight of eight tumour-derived cell lines and resulted in corresponding mRNA expression. The down-regulation of c-myc expression by TGF-beta 1 predominantly reflected growth inhibition by TGF-beta 1, but in two of eight tumour-derived cell lines which were partially responsive to TGF-beta 1 c-myc expression was unaltered by this ligand. While RB1 mRNA levels were unaltered by TGF-beta 1, the ligand caused the accumulation of the underphosphorylated form of the Rb protein in all cells irrespective of TGF-beta 1-induced growth arrest. junB expression was up-regulated by TGF-beta 1 in cells with a range of growth inhibitory responses. All cells contained mutant p53. TGF-beta 1 did not affect p53 mRNA expression in both tumour-derived and normal keratinocytes and there was no alteration in p53 protein levels in keratinocytes expressing stable p53 protein following TGF-beta 1 treatment. The data indicate that TGF-beta-induced growth control can exist independently of the presence of mutant p53 and the control of Rb phosphorylation and c-myc down-regulation. It may be that TGF-beta growth inhibition occurs via multiple mechanisms and that the loss of one pathway during tumour progression does not necessarily result in the abrogation of TGF-beta-induced growth control. PMID: 7547241 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 890: Oncogene. 1995 Sep 21;11(6):1013-8. Wild type p53 and c-myc co-operation in generating apoptosis of a rat hepatocellular carcinoma cell line (FAA-HTC1). Saito Y, Ogawa K. Department of Pathology, Asahikawa Medical College, Japan. p53 and c-myc are both known to be involved in apoptotic cell death as well as positive or negative regulation of cell proliferation, but it is not well established whether their functions are mechanistically correlated. We found that FAA-HTC1 cells, a rat hepatocellular carcinoma cell line, expressed c-myc independently of cell cycle and no detectable p53. To investigate possible co-operation between p53 and c-myc, the dexamethasone (Dex)-inducible wild type rat p53 was stably transfected into this cell line and c-myc expression was suppressed by treatment with c-myc antisense oligonucleotide (AS). p53 expression in the p53-introduced derivative resulted in apoptotic cell death, but it did not inhibit proliferative growth of the viable cells. On the other hand, when c-myc was suppressed in the p53-expressing cells, both apoptosis and cell growth were inhibited. These results indicate that p53 can act in the same cells either as a growth-inhibitor or apoptosis-inducer depending on the status of c-myc expression. PMID: 7566958 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 891: Arch Oral Biol. 1995 Sep;40(9):855-62. Gene expression of markers associated with proliferation and differentiation in human keratinocytes cultured from epidermis and from buccal mucosa. Brysk MM, Arany I, Brysk H, Chen SH, Calhoun KH, Tyring SK. Department of Dermatology, University of Texas Medical Branch, Galveston 77555, USA. Normal keratinocytes from epidermis and from buccal mucosa underwent dissimilar stages of differentiation in the same culture medium and responded differently to changes in the composition of the medium. Manifestations of these variations were examined in terms of the expression at the mRNA level (as measured by reverse transcriptase-polymerase chain reaction) of three regulatory genes (cdc2, c-myc, and p53) and five that encode structural proteins (keratins K5, K10 and K13, involucrin, and filaggrin), in three growth-medium formulations. The culture conditions enhanced or retarded maturation; the observed alterations in gene expression correlated with these changes. Except for the proliferation genes, the non-keratinizing buccal mucosa generally responded more weakly than the orthokeratotic epidermis to culture-medium supplementation favouring differentiation. Gene expression in cultured keratinocytes reflected their ability to differentiate in vivo; genes were expressed even when the corresponding protein was not seen in vitro. Although keratin K10 is not prevalent in the buccal mucosa nor keratin K13 in the epidermis, the genes for both were found to be expressed in both tissues. PMID: 8651890 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 892: Leuk Lymphoma. 1995 Sep;19(1-2):165-71. p53 mutations, c-myc and bcl-2 rearrangements in human non-Hodgkin's lymphoma cell lines. Chang H, Blondal JA, Benchimol S, Minden MD, Messner HA. Ontario Cancer Institute/Institute of Medical Science, University of Toronto, Canada. Fourteen Non-Hodgkin's lymphoma cell lines were generated and assessed for the presence of structural p53, c-myc and bcl-2 gene changes. Single or multiple changes were observed in 11 of the lines. Alterations of the p53 gene were most frequent and documented for 10 lines by immunoprecipitation using the antibodies PAb 240 and PAb 1801, sequencing studies and Southern blot analysis. A detailed study was performed in one of the cell lines (OCI-Ly 4) for which material of the original tumor sample was available. Two point mutations identified by sequencing cDNA derived from the cell line were also present in the original tumor specimen. In contrast, DNA prepared from fibroblasts of the same patient did not show the mutations. Six of the 14 lines demonstrated c-myc rearrangements, while bcl-2 changes were observed in 4. The presence of c-myc was associated with shorter survival of this group of patients with aggressive disease. None of the other changes present as single or composite alterations were correlated with clinical outcome measures. PMID: 8574164 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 893: Cancer Epidemiol Biomarkers Prev. 1995 Sep;4(6):617-25. Variation in the expression of p53, c-myc, and bcl-2 oncoproteins in individual patient cultures of normal urothelium exposed to cobalt 60 gamma-rays and N-nitrosodiethanolamine. Harney JV, Seymour CB, Murphy DM, Mothersill C. Department of Urology, Royal Liverpool University Hospital, United Kingdom. The controls determining the initial response of cells to DNA damage probably determine whether a cancer will ultimately occur. Efficient repair or apoptosis represents extremes of control mechanisms. Misrepair can lead to fixation of damage. The changes in oncoprotein expression of three genes involved in the regulation of repair of DNA damage and postdamage proliferation of cells were measured in cultures of normal urothelium from 55 patients without any malignancy. The aim was to obtain information on interperson variation in response to carcinogens in the human population. The group included 10 pediatric patients < 2 years old. Two different carcinogenic agents, ionizing radiation and N-nitrosodiethanolamine, which represent widely different DNA-damaging pathways, were used. Both of these cause bladder cancer in humans. Cells from explanted tissue were examined after carcinogen exposure for levels of p53, c-myc, and bcl-2 proteins. Both carcinogens led to increased levels of cytoplasmic p53 protein expression, although there was significant interpatient variation. bcl-2 showed a very significant increase in expression after radiation exposure. c-myc was high and variable pre- and postexposure. Individual patient culture changes in the expression of the three oncoproteins did not correlate significantly with each other or with cell growth, suggesting that the controls are complex. Pediatric samples had lower mean control values of p53 and bcl-2 than did adult samples. This was due to the absence in this group of high controls seen in some adult cultures. The result suggest that an early breakdown in control mechanisms of growth arrest and apoptosis may occur in urothelium after carcinogen exposure.(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 8547828 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 894: Cell Growth Differ. 1995 Sep;6(9):1071-5. bcl-2 inhibits wild-type p53-triggered apoptosis but not G1 cell cycle arrest and transactivation of WAF1 and bax. Wang Y, Okan I, Szekely L, Klein G, Wiman KG. Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden. We have earlier shown that wild-type (wt) p53 expressed from a temperature-sensitive construct (ts p53) triggers apoptosis in the v-myc retrovirus-induced, p53-negative T-cell lymphoma line J3D (Y. Wang et al., Cell Growth & Differ., 4: 467-473, 1993). We also found that constitutive bcl-2 expression inhibits wt p53-triggered apoptosis in these cells (Y. Wang et al., Oncogene, 8: 3427-3431, 1993). Here we demonstrate that more than 90% of the ts p53-transfected J3D cells were arrested in G1 at 18 h after induction of wt p53 expression by temperature shift to 32 degrees C. At this time, at least 80% of the cells remained viable. After 30 h at 32 degrees C, around 50% of the cells had died by apoptosis, while most of the remaining cells were still alive in G1, indicating that p53-induced apoptosis occurred following G1 arrest. The G1 cell cycle arrest at 18 h after temperature shift to 32 degrees C was reversible, as shown by the fact that the cells readily resumed exponential growth following temperature shift back to 37 degrees C, although viability dropped from around 80 to 65%. Expression of both WAF1 and bax mRNA was induced by wt p53 in both the ts p53 and ts p53/bcl-2 transfected cells. The kinetics of G1 cell cycle arrest at 32 degrees C was similar in both the ts p53 and the ts p53/bcl-2 double transfectants.(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 8519683 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 895: Genes Dev. 1995 Sep 1;9(17):2170-83. Induction of apoptosis in HeLa cells by trans-activation-deficient p53. Haupt Y, Rowan S, Shaulian E, Vousden KH, Oren M. Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel. The p53 tumor suppressor protein is a transcriptional activator, which can mediate apoptotic cell death in a variety of cell types. To determine whether sequence-specific trans-activation is a prerequisite for the induction of apoptosis by p53, the apoptotic effects of various p53 deletion mutants were monitored in an assay based on the transient transfection of HeLa cells. A truncated protein (p53dl214), containing only the first 214 amino-terminal residues of murine p53, induced extensive apoptosis, albeit at a slower rate than trans-activation-competent wild-type p53. p53dl214 also suppressed the transformation of rat fibroblasts by several oncogene combinations and particularly by myc plus ras and HPV E7 plus ras. p53dl214 lacks a major portion of the DNA-binding domain and cannot activate p53-responsive promoters. Moreover, a human p53 protein carrying mutations in residues 22 and 23 also triggered HeLa cell apoptosis, despite failing to induce significant activation of relevant p53 target promoters. These data suggest the existence of two p53-dependent apoptotic pathways--one requiring activation of specific target genes, and the other independent of sequence-specific trans-activation. The latter pathway may actually be totally uncoupled from the binding of p53 to its consensus DNA sites. The relative contribution of trans-activation-independent apoptosis to tumor suppression by p53 may be dictated by the specific genetic lesions present in the particular tumor. PMID: 7657168 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 896: No To Shinkei. 1995 Sep;47(9):829-34. [Therapy of malignant brain tumors by using apoptosis] [Article in Japanese] Kuchino Y. Biophysics Division, National Cancer Center Research Institute, Tokyo, Japan. Publication Types: Review Review, Tutorial PMID: 7546931 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 897: Clin Otolaryngol Allied Sci. 1995 Aug;20(4):291-8. Molecular alterations in head and neck squamous cell carcinoma. Bron L, Monnier P. Institut Universitaire de Pathologie, Lausanne, Switzerland. Publication Types: Review Review, Tutorial PMID: 8548956 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 898: Circ Res. 1995 Aug;77(2):266-73. Apoptosis of rat vascular smooth muscle cells is regulated by p53-dependent and -independent pathways. Bennett MR, Evan GI, Schwartz SM. Department of Pathology, University of Washington, Seattle, USA. Apoptosis of vascular smooth muscle cells has recently been described in culture and also in remodeling of the artery after birth. However, the genes that regulate apoptosis in smooth muscle cells are mostly unknown. We studied the regulation of apoptosis in rat smooth muscle cells stably infected with retrovirus constructs containing c-myc, adenovirus E1A, bcl-2, and a temperature-sensitive mutant of the tumor suppressor gene p53. Apoptosis was verified by electron microscopy and quantified by time-lapse videomicroscopy. Death was induced by c-myc and E1A when cells were deprived of serum survival factors, bcl-2 suppressed apoptosis of cells infected with c-myc and E1A and also normal smooth muscle cells. Overexpression of wild-type p53 induced apoptosis of cells infected with E1A and c-myc but not normal cells. In contrast, expression of mutant p53, which blocks wild-type p53 function, suppressed apoptosis of cells infected with E1A or c-myc but not normal cells. Both adenovirus E1A and c-myc increased the expression of endogenous p53 protein but not p53 mRNA. Although bcl-2 suppressed apoptosis induced by E1A and c-myc, upregulation of p53 protein induced by these agents was unaffected. We conclude that apoptosis of vascular smooth muscle cells is regulated by p53-dependent and -independent pathways. Death induced by c-myc and E1A is mediated by, and dependent on, p53. However, the suppression of apoptosis by bcl-2 is not mediated by changes in p53 expression, and the low level of apoptosis seen in normal VSMCs upon removal of survival factors is independent of p53. PMID: 7614713 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 899: Cancer Res. 1995 Aug 1;55(15):3310-7. Latent expression of p53 mutations and radiation-induced mammary cancer. Selvanayagam CS, Davis CM, Cornforth MN, Ullrich RL. Department of Radiation Therapy, University of Texas Medical Branch, Galveston 77555-0656, USA. EF42 is a clonally derived preneoplastic cell lineage from irradiated mouse mammary tissue, which becomes neoplastic with time in vitro or in vivo. We now report that multiple mutations in p53 occur before the acquisition of the neoplastic phenotype. The selective expansion of mutant cells is accompanied by loss of heterozygosity at the p53 locus and c-myc amplification. Although p53 mutations represent critical early events, our data argue these mutations were not directly induced by radiation but arose in the progeny of irradiated cells several cell generations later. The data are consistent with a multistep model of carcinogenesis that identifies genomic instability as the earliest step. PMID: 7614466 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 900: Cancer Lett. 1995 Jul 20;94(1):17-23. Cell death regulation during multistep lymphomagenesis. Hsu B, Marin MC, McDonnell TJ. Department of Molecular Pathology, University of Texas, M.D. Anderson Cancer Center, Houston 77030, USA. The three most common genetic abnormalities occurring in malignant lymphomas involve alterations resulting in the deregulated expression of the c-myc and bcl-2 oncogenes and the inactivation of the p53 tumor suppressor gene. Relevant strains of genetically engineered mice, including bcl-2-Ig and E mu-myc transgenic mice and p53 knockout mice, have been used to prospectively examine the regulation of apoptotic cell death by these genes, individually and in combination, and their contribution to in vivo lymphomagenesis. The potential importance of the therapeutic induction of apoptosis is discussed. PMID: 7621440 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 901: Cell. 1995 Jul 14;82(1):29-36. Absence of p53 allows direct immortalization of hematopoietic cells by the myc and raf oncogenes. Metz T, Harris AW, Adams JM. Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital Victoria, Australia. The p53 tumor suppressor is implicated here as a crucial barrier to unlimited cell proliferation. Its role in transformation of hematopoietic cells was studied by infecting fetal liver cells from wild-type or p53-/- mice with oncogenic retroviruses. Transformed colonies arose with a raf and a myc-raf virus. Absence of p53 did not affect their frequency but proved critical for their continued propagation. Colonies of p53-/- cells bearing both myc and raf readily yielded continuous cell lines without apparent requirement for genetic alteration. The lines, mainly of erythroid or myelomonocytic origin, were diploid but highly tumorigenic from their inception. These findings imply that p53 loss contributes directly to immortalization and tumorigenesis, probably by abrogating an intrinsic senescence program. PMID: 7606782 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 902: Oncogene. 1995 Jul 6;11(1):181-90. The MMTV/c-myc transgene and p53 null alleles collaborate to induce T-cell lymphomas, but not mammary carcinomas in transgenic mice. Elson A, Deng C, Campos-Torres J, Donehower LA, Leder P. Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, Massachusetts 02115, USA. A number of properties of the cancer-related genes c-myc and p53 suggest that they might collaborate to induce tumorigenesis. To test this notion, we produced doubly heterozygotic mice bearing disrupted p53 alleles and a fusion transgene consisting of the mouse mammary tumor virus (MMTV) LTR and the oncogene c-myc. Mice bearing both the MMT/c-myc transgene and a single p53- allele develop very aggressive pre-T- and T-cell lymphomas with a significantly shorter latency than mice carrying either the p53- allele or the c-myc transgene alone. Moreover, every lymphoma occurring in these animals has lost or suffers an inactivation of its wild type p53 allele indicating that loss of p53 activity is necessary for this c-myc-accelerated lymphomagenesis. Nonetheless, p53 inactivation and expression of the MMTV/c-myc transgene are not sufficient for lymphoid transformation. Tumors that arise in homozygous p53- mice carrying the c-myc transgene are monoclonal, suggesting that at least one additional event is necessary for their transformation. Moreover, since mice bearing only the MMTV/c-myc transgene predominantly develop mammary carcinomas, it was surprising that the p53- allele failed to accelerate the incidence of mammary carcinomas. Further, in contrast to the lymphomas, only one in four mammary tumors that arose in the double heterozygotic mice had lost its wild type p53 allele. Apparently cell context influences the ability of c-myc and p53- to cooperate in inducing oncogenesis. PMID: 7624126 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 903: Oncogene. 1995 Jul 6;11(1):175-9. Evidence that c-myc mediated apoptosis does not require wild-type p53 during lymphomagenesis. Hsu B, Marin MC, el-Naggar AK, Stephens LC, Brisbay S, McDonnell TJ. Department of Molecular Pathology, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA. Deregulation of c-myc, frequently implicated in oncogenesis, is associated with increased cell proliferation and also cell death. Similarly, the p53 tumor suppressor gene commonly mutated in human tumors, is known to induce apoptosis or cell cycle arrest in its wild-type conformation. Genetically altered mice simultaneously overexpressing c-myc and possessing a disrupted p53 gene were used to investigate whether c-myc mediated apoptosis requires wild-type p53. The accelerated development of malignant lymphomas in these mice was found to be a consequence of enhanced proliferation and not reduced apoptosis resulting from the synergistic effect of c-myc overexpression and p53 inactivation. PMID: 7624125 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 904: Oncogene. 1995 Jul 6;11(1):15-20. Differences in sensitivity to induction of apoptosis among rat fibroblast cells transformed by HTLV-I tax gene or cellular nuclear oncogenes. Fujita M, Shiku H. Department of Oncology, Nagasaki University School of Medicine, Japan. The tax gene of human T lymphotropic virus type I has been implicated in the genesis of adult T cell leukemia (ATL). It has been reported that expression of tax induces neoplastic transformation in the rat fibroblast cell line Rat-1, and that co-expression with the ras gene can transform rat embryo fibroblasts. Possible activation of cellular oncogenes including c-myc and c-fos by tax has been implicated in these tax functions. In this study, comparative analysis of biological properties of tax and cellular nuclear oncogenes c-myc and c-fos was performed in Rat-1 cells. While all three oncogenes could transform Rat-1 cells, significant differences in the sensitivity to induction of apoptosis were observed between cells transformed with each oncogene. Induction of apoptosis by serum starvation was observed in tax-transfected Rat-1 cells but to a lesser extent than that in those transfected with c-myc or c-fos. In contrast, exposure to a DNA-damaging agent, etoposide, resulted in enhanced apoptotic death only in c-myc-transfected Rat-1 cells. Our findings indicate that the pathways for apoptosis induction may not be identical among these three oncogenes, and that the relatively low apoptosis-inducing activity and sufficient transforming capacity of tax might be associated with transformation of T cells and the low susceptibility of the transformed T cells (ATL cells) to chemotherapeutic agents. PMID: 7624122 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 905: Genes Chromosomes Cancer. 1995 Jul;13(3):175-85. Identification of novel regions of altered DNA copy number in small cell lung tumors. Levin NA, Brzoska PM, Warnock ML, Gray JW, Christman MF. Department of Radiation Oncology, University of California, San Francisco 94143, USA. Identification of the genetic alterations that occur in tumors is an important approach to understanding tumorigenesis. We have used comparative genomic hybridization (CGH), a novel molecular cytogenetic method, to identify the gross DNA copy number changes that commonly occur in small cell lung cancer (SCLC). We analyzed ten SCLC tumors (seven primary tumors and three metastases) from eight patients. We found frequent increases in DNA copy number on chromosome arms 5p, 8q, 3q, and Xq and frequent decreases in copy number on chromosome arms 3p, 17p, 5q, 8p, 13q, and 4p. The increase in copy number at 8q24 (MYC) and decreases at 17p13 (TP53), 13q14 (RB), and 3p have previously been identified in SCLC with other methods. Many of the other regions in which we detected common copy number changes have not been reported to be regions of common alteration in SCLC tumors. Comparison of copy number changes between a primary tumor and a metastasis from the same patient showed that they were more closely related to each other than to any of the other tumors. The results of direct CGH analysis of SCLC tumors reported here confirm the existence of copy number changes that we identified previously by using cell lines. PMID: 7669737 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 906: Anticancer Res. 1995 Jul-Aug;15(4):1205-13. Cellular genes possibly involved in the transformation process of the human melanoma cell line XP44 RO (Mel). Lafarge-Frayssinet C, Daya-Grosjean L, Estrade S, Frezouls G, Sarasin A, Cassingena R. Laboratory of Molecular Genetics, UPR 42 CNRS, Institut de Recherches sur le Cancer, CNRS IFC 1, Villejuif, France. P44 Ro (Mel) is a human malignant melanoma cell line derived from a testicular metastasis in a DNA repair deficient, xeroderma pigmentosum patient. This line harbors a N-ras gene mutated in codon 61. To investigate other cellular genes possibly contributing to the expression of its transformed phenotype, four XP44 revertant cell lines were isolated by different selection procedures and the association of the level of expression of various oncogenes (including N-ras) and tumor suppressor genes with the selection for the revertant phenotype was determined. The revertants exhibited a significant but variable degree of phenotypic reversion, according to the selective pressure to which they were submitted, and a phenotypic stability dependent on their constant maintenance in selective medium. Back-revertant lines were isolated by culturing revertant lines in control medium for several weeks. The comparison between parental, revertant and back-revertant cells has revealed that, beyond the mutation in codon 61 of N-ras, two groups of genes appear to be also implicated in the transformation process of XP44 RO (Mel) cells: one group, comprising pim A, trk, Rb and p53, whose expression is independent of the cell selection conditions; the other group, comprising Ha-ras, N-ras, neu 1, fos and met H, whose expression is more or less dependent upon such conditions. The myc gene is apparently not involved in this phenomenon. These results, besides strengthening the concept that carcinogenesis is a multigenic process, suggest that diverse mechanisms can lead to the transformed phenotype, but that these mechanisms might have some pathway(s) in common. PMID: 7654000 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 907: Ann Surg. 1995 Jun;221(6):706-18; discussion 718-20. Comment in: Ann Surg. 1996 Nov;224(5):686-8. Oncogene protein co-expression. Value of Ha-ras, c-myc, c-fos, and p53 as prognostic discriminants for breast carcinoma. Bland KI, Konstadoulakis MM, Vezeridis MP, Wanebo HJ. Department of Surgery, Brown University School of Medicine, Providence, Rhode Island, USA. OBJECTIVE: A refinement of prognostic variables using traditional pathologic markers integrated with oncogene proteins, enzymes, and hormonal factors may enhance the ability to predict for recurrence or survival in patients with mammary carcinoma. Although various oncogenes and oncogene products have been identified in human breast carcinoma, their relationship to disease outcome remains controversial. METHODS: Using the monoclonal antibodies cS93.1, 9E1.0, F235-1.7.1, and PAb 1801 against each oncogene protein studied, the avidin-biotin complex immunoperoxidase method provided immunohistochemical staining of bound oncogene protein for c-fos, c-myc, Ha-ras, and p53, respectively. Analyses were made on archival pathology tissues of 85 breast cancer patients (stages I, IIA, and IIB). Forty patients (47%) had recurrence of disease; 45 remained free of local-regional or distant disease at mean follow-up of 48 months (range 6-180 months). Molecular biological data were merged with clinicopathologic demographics 1) to determine the frequency of single or co-expression of oncogenes in this patient population; 2) to evaluate the value of these molecular protein markers to predict probability of recurrence; and 3) to determine worth of the studied oncogenes to correlate with traditional clinical pathologic parameters and overall survival. RESULTS: In this study, oncogene expression had statistical correlation for recurrence with increasing co-expression: one oncogene 17.2%, two oncogenes 56.3%, three or four oncogenes, 100% (p = 0.001). Increasing oncogene or co-oncogene expression correlated with statistically significant reduction in disease-free and overall survival; with no expression of oncogenes, disease-free survival was 30 (SE +/- 5.7) months and overall survival was 56.4 (SE +/- 4.57) months. With expression of three oncogenes, disease-free survival was 12 (SE +/- 1.23) months (p = 0.0018) and overall survival was 23.4 (SE +/- 3.38) months (p = 0.0025). In univariate Wilcoxon analysis, oncogene expression was the most significant variable to determine survival (p = 0.035); in multivariate analysis, age and oncogene co-expression each emerged as the most significant variables for overall survival. For the proportional hazards regression model, oncogene co-expression was significant (p = 0.0104, risk-ratio 1.914) and correlated with age and tumor size as significant variables. Ha-ras and c-fos both emerged as important individual oncogene proteins to affect survival (p = 0.0925, risk-ratio 3.517 and p = 0.025, risk-ratio 4.214, respectively). The proto-oncogene c-myc and the antitumor suppressor gene p53 did not have significant effects as individual oncogenes to influence survival. CONCLUSIONS: Approximately one fifth of the breast cancer patients in this analysis (disease-free and recurrent) expressed only a single oncogene marker (c-fos, c-myc, Ha-ras, or p53); one quarter of patients with recurrent disease expressed only one oncogene protein. Single oncogene expression did not possess independent prognostic significance for prediction of recurrence. Further, p53 mutations did not function as independent correlates for prognosis. The co-expression of the studied proto-oncogenes (c-myc, Ha-ras) and the nuclear transcriptional protein (c-fos) functioned as a strong prognostic correlate for recurrence and survival; the effect of individual oncogenes to predict survival was greatest for Ha-ras and c-fos. Immediate or early co-expression of three oncogene proteins in neoplastic transformation endowed cells of invasive carcinoma with an aggressive phenotype. This aggressive phenotype was evident in a small percentage of the studied population (11%) and predicted adverse disease-free and overall survival. These findings suggest that oncogene co-expression possesses significant prognostic and potential therapeutic value; incorporation of this molecular technology into future prospective randomized trials is advisable. PMID: 7794075 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 908: Oncogene. 1995 Jun 1;10(11):2145-53. Combined oral carcinogenicity of HPV-16 and benzo(a)pyrene: an in vitro multistep carcinogenesis model. Park NH, Gujuluva CN, Baek JH, Cherrick HM, Shin KH, Min BM. Dental Research Institute, University of California, Los Angeles 90024, USA. We previously immortalized normal human oral keratinocytes by transfection with recombinant HPV-16 DNA and subsequently exposed the cells to benzo(a)pyrene for 7 days. The exposure to benzo(a)pyrene modified the immortalized cells: the modified cells (HOK-16B-BaP) proliferated in an ordinary culture medium containing physiological calcium level (1.5 mM), but demonstrated only enhanced proliferation capacity without tumor formation in nude mice and failed to show in vitro anchorage-independency. In this study, we further modified the HOK-16B-BaP cells by subculturing the cells in a medium containing benzo(a)pyrene for 6 months. The cells were further modified with a chronic benzo(a)pyrene exposure and were termed HOK-16B-BaP-T cells (1) demonstrated a malignant phenotype in organotypic 'raft' culture, (2) showed in vitro anchorage-independency, (3) developed tumors in nude mice when injected subcutaneously, (4) contained a significantly higher copy number of intact and integrated HPV-16 DNA; (5) contained higher level of HPV-16 E6/E7 messages and E7 protein, (6) were more resistant to transforming growth factor-beta 1 and (7) secreted higher level of vascular endothelial growth factor with molecular weight of 56 kd than parental HOK-16B-BaP cells. However, the levels of p53 and ras proteins and the levels of p53, c-myc and c-fos transcripts in the HOK-16B-BaP-T cells were not different from those in the HOK-16B-BaP cells. The highly conserved coding regions of the p53, c-Ha-ras1, and c-Ki-ras2 genes of the tumor cells were not mutated. These data indicate that the HPV-immortalized human oral keratinocytes can convert to tumorigenic cells by chronic exposure to benzo(a)pyrene. The tumorigenic conversion seems to be associated with (1) the overexpression of viral oncogenes such as E6 and E7 genes, (2) the higher resistance of cells to transforming growth factor-beta 1 and (3) the high secretion of 56 kd vascular endothelial growth factor from the cells. PMID: 7784058 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 909: Am J Pathol. 1995 Jun;146(6):1368-75. Castration therapy rapidly induces apoptosis in a minority and decreases cell proliferation in a majority of human prostatic tumors. Westin P, Stattin P, Damber JE, Bergh A. Department of Pathology, University of Umea, Sweden. Major differences in the long-term clinical response to castration therapy of prostatic carcinoma suggests intertumoral differences in cellular response and defines a need for identification of patients with an eventually positive outcome as well as those in need of additional treatment. Using morphometry, monoclonal antibodies against Bcl-2, c-myc, Ki-67, and p53 proteins, and an in situ method to visualize apoptotic cells, we examined the short-term response of prostatic tumors to castration in core biopsies from 18 prostatic cancer patients taken the day before and 7 days after castration. At the histological level, 3 tumors seemed practically unaffected by castration. In 15 tumors, castration induced vacuolization of tumor cell cytoplasm and decreases in nuclear area and Ki-67 index. In these 15 tumors, apoptotic index was significantly increased in 6, principally unaffected in 6, and decreased in 3. The 6 tumors responding with an increase in apoptotic index were WHO grade 1 or 2 and negative for p53, c-myc, and Bcl-2 or contained only few Bcl-2- or c-myc-positive tumor cells before therapy. The 12 tumors in which apoptotic index was unaffected or decreased were WHO grade 2 or 3 and immunopositive for one or more of p53, Bcl-2, and c-myc proteins before therapy. The Bcl-2 index was significantly increased in 10 patients. Prostatic tumors may respond in a variety of possibly predictable ways to castration therapy including a decrease in apoptotic index. The magnitude of these responses are not correlated in individual tumors, suggesting that the common classification of prostatic tumors as either androgen dependent (dying after castration) or independent (not responding at all to castration) may be an oversimplification. PMID: 7778676 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 910: Biochem Mol Biol Int. 1995 Jun;36(2):393-400. Expression of the protooncogene mdm2 markedly increases in response to carbon tetrachloride but not after partial hepatectomy in contrast to p53. Kubin T, Gohda E, Yamamoto I. Department of Immunochemistry, Faculty of Pharmaceutical Sciences, Okayama University, Japan. The p53 tumor-suppressor gene is the most commonly altered gene in human cancers. Here we demonstrate that transcripts of the mdm2 gene, which encodes a cellular p53 binding protein, markedly increased in the rat liver within 1 to 3 h, reached a peak at 12 h and returned to the basal level 48 h after the administration of carbon tetrachloride. However, the level of hepatic mdm2 mRNA did not significantly change after partial hepatectomy. This is in contrast to p53 gene expression which increased after either procedure. C-myc transcripts also rapidly increased after the injection of carbon tetrachloride, reaching a maximal level at 3 h. The activity of serum alanine aminotransferase was low within the first 12 h and was maximal 24 h after carbon tetrachloride. These results suggest that the transient hepatic expression of the mdm2 gene prior to the onset of cell death is more likely to reflect events associated with necrosis rather than with cell proliferation. PMID: 7663443 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 911: Radiat Environ Biophys. 1995 Jun;34(2):79-83. Effects of ionizing radiation on cell cycle progression. A review. Bernhard EJ, Maity A, Muschel RJ, McKenna WG. Department of Radiation Oncology, University of Pennsylvania School of Medicine, Philadelphia 19104, USA. Irradiation of normal eukaryotic cells results in delayed progression through the G1, S, and G2 phases of the cell cycle. The G1 arrest is regulated by the p53 tumor suppressor gene product. Irradiation results in increased expression of p53, which in turn induces a 21 kDa protein, WAF1/Cip 1, that inhibits cyclin CDK kinases. S-phase delay is observed after relatively high doses of radiation. This delay has both radiosensitive and radioresistant components, corresponding to inhibition of DNA replicon initiation and DNA chain elongation, respectively. The mechanism for this delay is as yet undefined, but the extent of the delay appears to be under genetic control and is sensitive to the kinase inhibitor staurosporine. A delay in G2 has been demonstrated in virtually all eukaryotic cells examined in response to irradiation. Our studies have focused on the mechanisms responsible for this delay. Cyclin B1 and p34cdc2 are cell cycle control proteins that together form a kinase complex required for passage through G2 and mitosis [22]. Control of radiation-induced G2 delay is likely therefore to involve modulation of cyclin B1/p34cdc2 activity. We have shown in HeLa cells that cyclin B1 expression is decreased in a dose-dependent manner following irradiation. This decrease is controlled at both the level of mRNA and protein accumulation. We have also shown that radiation-sensitive rat embryo fibroblast lines (REF) immortalized with v- or c-myc display a minimal G2 delay when compared to radiation resistant cells transformed with v-myc + H-ras. These REF lines respond to irradiation with a decrease in cyclin B mRNA, which parallels the extent of their respective G2 delays.(ABSTRACT TRUNCATED AT 250 WORDS) Publication Types: Review Review, Tutorial PMID: 7652155 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 912: Gan To Kagaku Ryoho. 1995 Jun;22 Suppl 2:158-63. [Detection of loss of heterozygosity by microsatellite probe and DNA content analysis] [Article in Japanese] Chiba W, Sawai S, Ikeda S, Kinoshita M, Hatama T, Shin S, Fujimoto T, Miyajima S, Wazawa H, Hanawa T, et al. Respiratory Disease Center, Kyoto Katsura Hospital. We examined replication error (RER) and loss of heterozygosity (LOH) in the region of microsatellites in 60 cases of resected lung cancer. We used microsatellite probes for the short arm of the 2nd chromosome (D2S123, D2S136), the short arm of the 3rd chromosome (D3S1067), and the short arm of the 17th chromosome (TP53). According to stage, the frequency of LOH was 25% in stage I, 33% in stage II, 44% in stage IIIA, 11% in stage III B, and 63% in stage IV. According to histological classification, the frequency of LOH was 41% for squamous cell carcinoma, 24% for adenocarcinoma, and 100% for small cell carcinoma. According to microsatellite probe results, the frequency of LOH was 6.7% for D2S123, 5.0% for D2S136, 16.7% for D3S1067, and 18.3% for TP53. Two of the 60 cases showed RER. One case was stage I squamous cell carcinoma, and the other was stage IV adenocarcinoma. Except for stage III B,LOH in the microsatellite region increases with the stage. LOH is often detected in the order of small cell carcinoma, squamous cell carcinoma, and adenocarcinoma. According to the chromosome number, LOH is detected more often in the 3rd and 17th chromosomes than in the 2nd chromosome. In 20 cases with LOH, only two showed DNA diploidy. Compared to LOH of the microsatellite region, DNA content analysis by flow cytometry has accuracy problems. PMID: 7611781 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 913: Leukemia. 1995 Jun;9(6):955-9. p53 gene inactivation in acute lymphoblastic leukemia of B cell lineage associates with chromosomal breakpoints at 11q23 and 8q24. Lanza C, Gaidano G, Cimino G, Lo Coco F, Basso G, Sainati L, Pastore C, Nomdedeu J, Volpe G, Parvis G, et al. Dipartimento di Scienze Biomediche e Oncologia Umana, Ospedale San Luigi Gonzaga, Torino, Italy. The clinical heterogeneity of acute lymphoblastic leukemia (ALL) of B cell lineage reflects the presence of distinct molecular pathways leading to well-defined ALL molecular subtypes. These molecular pathways include the formation of the fusion transcripts BCR/ABL and E2A/PBX1, due to t(9;22) and t(1;19), respectively, as well as rearrangements of the MLL gene at 11q23 and of c-MYC at 8q24. Hyperdiploid ALL in the absence of chromosomal structural abnormalities is an additional ALL molecular subtype. Mutations of the RAS family genes and of the p53 tumor suppressor gene represent additional genetic lesions detected in a fraction (10-20%) of ALL cases. RAS activation in ALL may be detected in all molecular subtypes of ALL and denotes poor prognosis. Conversely, little is known regarding the clinical and biological features of ALL cases carrying p53 mutations. In order to help clarify the role of p53 inactivation in ALL development, we have determined the frequency of p53 mutations throughout the molecular spectrum of B cell lineage ALL. We report that p53 inactivation in ALL of B cell lineage is restricted to cases carrying a rearrangement of MLL or c-MYC, whereas it is consistently negative in other molecular subgroups. These data underline the molecular heterogeneity of ALL of B cell lineage and indicate that at least some of the molecular pathways involved in ALL pathogenesis require more than one genetic lesion. PMID: 7596184 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 914: Blood. 1995 May 15;85(10):2691-8. Dissection of the genetic programs of p53-mediated G1 growth arrest and apoptosis: blocking p53-induced apoptosis unmasks G1 arrest. Guillouf C, Grana X, Selvakumaran M, De Luca A, Giordano A, Hoffman B, Liebermann DA. Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA. Employing the myeloblastic leukemia M1 cell line, which does not express endogenous p53, and genetically engineered variants, it was recently shown that activation of p53, using a p53 temperature-sensitive mutant transgene (p53ts), resulted in rapid apoptosis that was delayed by high level ectopic expression of bcl-2. In this report, advantage has been taken of these M1 variants to investigate the relationship between p53-mediated G1 arrest and apoptosis. Flow cytometric cell cycle analysis has provided evidence that activation of wild-type (wt) p53 function in M1 cells resulted in the induction of G1 growth arrest; this was clearly seen in the M1p53/bcl-2 cells because of the delay in apoptosis that unmasked p53-induced G1 growth arrest. This finding was further corroborated at the molecular level by analysis of the expression and function of key cell cycle regulatory genes in M1p53 versus M1p53/bcl-2 cells after the activation of wt p53 function; events that take place at early times during the p53-induced G1 arrest occur in both the M1p53 and the M1p53/bcl-2 cells, whereas later events occur only in the M1p53/bcl-2 cells, which undergo delayed apoptosis, thereby allowing the cells to complete G1 arrest. Finally, it was observed that a spectrum of p53 target genes implicated in p53-induced growth suppression and apoptosis were similarly regulated, either induced (gadd45, waf1, mdm2, and bax) or suppressed (c-myc and bcl-2), after activation of wt p53 function in M1p53 and M1p53/bcl-2 cells. Taken together, these findings show that wt p53 can simultaneously induce the genetic programs of both G1 growth arrest and apoptosis within the same cell type, in which the genetic program of cell death can proceed in either G1-arrested (M1p53/bcl-2) or cycling (M1p53) cells. These findings increase our understanding of the functions of p53 as a tumor suppressor and how alterations in these functions could contribute to malignancy. PMID: 7742528 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 915: Proc Natl Acad Sci U S A. 1995 May 9;92(10):4407-11. Wild-type p53 protein undergoes cytoplasmic sequestration in undifferentiated neuroblastomas but not in differentiated tumors. Moll UM, LaQuaglia M, Benard J, Riou G. Department of Pathology, State University of New York, Stony Brook 11794-8691, USA. Neuroblastoma (NB), a tumor arising from the sympathetic nervous system, is one of the most common malignancies in childhood. Several recent reports on the p53 genotype found virtually exclusive wild-type status in primary tumors, and it was postulated that p53 plays no role in the development of NB. Here, however, we report that the vast majority of undifferentiated NBs exhibit abnormal cytoplasmic sequestration of wild-type p53. This inability of p53 to translocate to the nucleus presumably prevents the protein from functioning as a suppressor. Thirty of 31 cases (96%) of undifferentiated NB showed elevated levels of wild-type p53 in the cytoplasm of all tumor cells concomittant with a lack of nuclear staining. p53 immunoprecipitation from tumor tissues showed a 4.5- to 8-fold increase over normal protein levels. All of 10 tumors analyzed harbored wild-type p53 by direct sequencing of full-length cDNA and Southern blot. In addition, no MDM-2 gene amplification was seen in all 11 tumors analyzed. In contrast, no p53 abnormality was detected in 14 differentiated ganglioneuroblastomas and 1 benign ganglioneuroma. We conclude that loss of p53 function seems to play a major role in the tumorigenesis of undifferentiated NB. This tumor might abrogate the transactivating function of p53 by inhibiting its access to the nucleus, rather than by gene mutation. Importantly, our results suggest that (i) this could be a general mechanism for p53 inactivation not limited to breast cancer (where we first described it) and that (ii) it is found in a tumor previously not thought to be affected by p53 alteration. PMID: 7753819 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 916: Oncogene. 1995 May 4;10(9):1717-23. Synergy between a human c-myc transgene and p53 null genotype in murine thymic lymphomas: contrasting effects of homozygous and heterozygous p53 loss. Blyth K, Terry A, O'Hara M, Baxter EW, Campbell M, Stewart M, Donehower LA, Onions DE, Neil JC, Cameron ER. Department of Veterinary Pathology, University of Glasgow Veterinary School, Bearsden, UK. Activation of the c-myc oncogene and functional loss of the p53 tumour suppressor gene are among the most frequently recorded genetic lesions in neoplasia but their combined effect has not previously been investigated. By breeding together mice transgenic for human c-myc (CD2-myc) and mice carrying an inactive p53 allele (p53-/-) we found that these genetic lesions act synergistically in vivo. Offspring carrying the CD2-myc transgene and the homozygous p53 null mutation (p53-/-/CD2-myc) were viable but developed thymic lymphomas with dramatically increased frequency and reduced latency compared to both parental groups. The tumour phenotype was similar to that previously recorded for CD2-myc mice (predominantly CD3+, CD4+8+) but tumour clonal complexity and metastasis was significantly greater in the p53-/-/CD2-myc mice. In contrast, no significant increase in tumour incidence was seen in p53+/-/CD2-myc vs p53+/+/CD2-myc mice over a 6 month observation period. However, the loss of wild type p53 in a proportion of tumour cells in p53+/-/CD2-myc lymphomas suggests that wild type allele loss can occur as a late progression step rather than an initiating step in these tumours. We suggest that p53 loss of function may collaborate with the CD2-myc transgene at more than one stage in thymic lymphoma development. PMID: 7753548 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 917: Am J Pathol. 1995 May;146(5):1131-9. c-myc copy number gains in bladder cancer detected by fluorescence in situ hybridization. Sauter G, Carroll P, Moch H, Kallioniemi A, Kerschmann R, Narayan P, Mihatsch MJ, Waldman FM. Department of Laboratory Medicine, University of California, San Francisco, USA. Amplification and overexpression of c-myc have been suggested as prognostic markers in human cancer. To assess the role of c-myc gene copy number alterations in bladder cancer, 87 bladder tumors were examined for c-myc aberrations by fluorescence in situ hybridization. Dual labeling hybridization with a repetitive pericentromeric probe specific for chromosome 8 and a probe for the c-myc locus (at 8q24) was performed to analyze c-myc copy number in relation to chromosome 8 copy number on a cell by cell basis. A clear-cut c-myc amplification (up to 40 to 150 copies per cell) was found in 3 tumors. There was a low level c-myc copy number increase in 32 of the remaining 84 tumors. There was no association of low level c-myc copy number increase with c-myc protein overexpression. This suggests that a c-myc gene copy number gain as detected by fluorescence in situ hybridization does not necessarily reflect a disturbed c-myc gene function but may indicate a structural chromosome 8 abnormality including gain of distal 8q. The strong association of low level c-myc (8q) gains with tumor grade (P < 0.0001), stage (P < 0.0001), chromosome polysomy (P < 0.0001), p53 protein expression (P = 0.0019), p53 deletion (P = 0.0403), and tumor cell proliferation (Ki67 labeling index; P = 0.0021) is consistent with a role of chromosome 8 alterations in bladder cancer progression. PMID: 7747807 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 918: Radiat Res. 1995 May;142(2):181-7. Primary explants of human uroepithelium show an unusual response to low-dose irradiation with cobalt-60 gamma rays. Mothersill C, Harney J, Lyng F, Cottell D, Parsons K, Murphy DM, Seymour CB. Department of Physics, Dublin Institute of Technology, Ireland. Recent results using very low doses of radiation have suggested that there is a hypersensitive region where cultures show an enhanced level of cell killing leading to a non-monotonic survival curve. This effect has been observed at doses below 2 Gy in mammalian systems and at much higher doses in insect cells. In this paper we report observation of the effect in primary human uroepithelial cell cultures. The effect was measured using a postirradiation proliferation assay where irradiated explants of standard size were allowed to proliferate for 14 days after exposure to 60Co gamma irradiation. By 14 days the majority of cultures derived from explants irradiated with 2-5 Gy showed little evidence of growth inhibition and cell numbers approached or even exceeded those obtained in the controls. There was, however, a significant reduction in cell number and growth rate in all cultures exposed to doses lower than 1 Gy. Oncoprotein (p53, c-myc, bcl-2, p21 ras) and EGFR expression were also measured in these cultures and were significantly increased. Morphological evidence of apoptosis was present in all irradiated cultures at 4 h after exposure, but this persisted for longer periods in cultures exposed to low doses. PMID: 7724733 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 919: Endocrinology. 1995 May;136(5):1898-906. Androgen ablation-induced programmed death of prostatic glandular cells does not involve recruitment into a defective cell cycle or p53 induction. Furuya Y, Lin XS, Walsh JC, Nelson WG, Isaacs JT. Johns Hopkins Oncology Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. Proliferating cells characteristically undergo programmed (i.e. apoptotic) death if their progression through the cell cycle is sufficiently perturbed. To determine whether androgen ablation-induced programmed death of prostatic glandular cells involves apoptosis triggered by recruitment of nonproliferating cells into a perturbed cell cycle, rat ventral prostates were assessed temporally after castration for several stereotypical molecular stigmata of entry into the proliferative cell cycle. Northern blot analysis was used to assess levels of transcripts from genes characteristically activated 1) during the transition from quiescence (G(0)) into G1 of the proliferative cell cycle (cyclin-D1 and cyclin-C), 2) during the transition from G1 to S (cyclin-E, cdk2, thymidine kinase, and H4-histone), and 3) during progression through S (cyclin-A). Although levels of each of these transcripts increased as expected in prostatic glandular epithelial cells stimulated to proliferate by the administration of exogenous androgen to previously castrated rats, levels of the same transcripts decreased in prostatic glandular cells induced to undergo apoptosis after androgen withdrawal. Northern and Western blot analyses also demonstrated that there was no increase in prostatic p53 messenger RNA or protein content per cell after androgen ablation. Likewise, after castration, there was no enhanced prostatic expression of the WAF1/CIP1 gene, a gene whose expression is known to be induced in both a p53-dependent and -independent manner during recruitment from G0 into G1. In addition, androgen ablation-induced apoptosis of prostatic glandular cells was not accompanied by retinoblastoma protein phosphorylation, which is characteristic of progression into late G1. Nuclear run-on assays demonstrated that there was no increase in the prostatic rate of transcription of the c-myc and c-fos genes after castration. These results demonstrate that prostatic glandular cells undergo programmed death in G(0) without recruitment into the G1 phase of a defective cell cycle, and that an increase in p53 protein or its function is not involved in this death process. PMID: 7720636 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 920: Int J Cancer. 1995 Apr 21;64(2):140-5. Association between RB-1 gene alterations and factors of favourable prognosis in human breast cancer, without effect on survival. Berns EM, de Klein A, van Putten WL, van Staveren IL, Bootsma A, Klijn JG, Foekens JA. Department of Medical Oncology, Dr. Daniel den Hoed Cancer Center, Rotterdam, The Netherlands. The retinoblastoma (RB) tumour suppressor gene has been associated not only with retinoblastoma but also with several other tumours like osteosarcoma, small cell lung carcinoma and prostate and breast cancer. We have studied the incidence of RB gene alterations in 96 primary breast tumours using Southern blotting techniques. The outcome has been related with patient and tumour characteristics, oncogene amplifications, p53 mutations and prognosis. RB gene alterations were found to occur more frequently in estrogen receptor (ER)-positive than in ER-negative tumours and less frequently in tumours with oncogene amplification than in tumours without oncogene amplification of HER2/neu, c-myc or 11q13. RB gene alteration was observed in tumours both with and without a p53 gene mutation. Data on 87 patients (mean age, 59.6 years; median follow-up, 108 months) and RB gene alterations revealed a significant association between the frequency of RB gene alterations and node-negative patients (p < 0.01) or smaller (< 2 cm) tumours (p < 0.01), but no relation with age, differentiation grade or (relapse-free) survival. Patients with and without RB gene alterations showed the same relapse-free and overall survival. PMID: 7615356 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 921: Eur J Cancer Prev. 1995 Apr;4(2):129-38. Clinical tumour markers in lung cancer. Niklinski J, Furman M. Department of Thoracic Surgery, Medical School, Bialystok, Poland. Within the past few years, the measurement of serum and tissue markers has had an increasing influence on clinical decisions about initial treatment and follow-up. Lung cancer illustrates the types and importance of these various markers. This review presents data concerning the most studied and interesting markers in non-small cell (NSCLC) and small cell lung cancer (SCLC). CEA, TPA, SCC-Ag, CYFRA 21-1, ferritin, CA19-9, CA50, CA242, H-K-N-ras mutations and p53 mutation seem to be the most prolific in NSCLC, while NSE, BN/GRP, CK-BB, NCAM, IL-2R, IGF-I, transferrin, ANP, mAb (cluster 5), Le-y and c-N-L-myc mutation are markers in SCLC patients. Some of these serum markers might be useful adjuncts for monitoring response to therapy, including early detection of tumour reactivation to allow curative therapy and rapid detection of treatment failure to allow change of the regimen. The study of these markers also may lead to a better understanding of the biological characteristics of lung cancer. The information derived from these biological studies represents the most promising avenue towards new treatment strategies, as well as attempts at secondary prevention. Publication Types: Review Review, Tutorial PMID: 7539317 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 922: Oncogene. 1995 Mar 16;10(6):1081-6. Non-syntenic amplification of MDM2 and MYCN in human neuroblastoma. Corvi R, Savelyeva L, Breit S, Wenzel A, Handgretinger R, Barak J, Oren M, Amler L, Schwab M. Division of Cytogenetics, German Cancer Research Center, Heidelberg. Amplification of the MYCN gene is a well documented genetic alteration of aggressively growing human neuroblastomas. Through cytogenetic studies we have identified neuroblastoma cell lines which, in addition to amplified MYCN, carry amplified DNA not harbouring MYCN. In situ hybridization of biotinylated total genomic DNA to metaphase chromosomes of normal human lymphocytes by reverse genomic hybridization revealed the amplified DNA to be derived from chromosome 12 band q13-14. Subsequent filter analyses showed a 20- to 40-fold amplification of the MDM2 gene, located at 12q13-14, both in three cell lines and in an original tumor, in addition to amplified MYCN. As the apparent consequence of amplification abundant MDM2 protein was present, a part of which was complexed with p53. PMID: 7700632 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 923: Cancer. 1995 Mar 15;75(6):1292-301. Multiple genetic lesions in laryngeal squamous cell carcinomas. Fracchiolla NS, Pignataro L, Capaccio P, Trecca D, Boletini A, Ottaviani A, Polli E, Maiolo AT, Neri A. Laboratorio di Ematologia Sperimentale e Genetica Molecolare, Universita di Milano, Ospedale, Maggiore, Milan, Italy. BACKGROUND. To understand the molecular pathogenesis of laryngeal squamous cell carcinomas (LSCCs), this study investigated the involvement of various protooncogene loci (bcl-1, int-2, c-erbB-1, c-myc, ras) and the p53 tumor suppressor gene in 18 patients with LSCC (15 at clinical presentation, 3 in clinical relapse). METHODS. For all patients, the mutations affecting the p53 and the H-, K-, and N-ras genes were evaluated by polymerase chain reaction (PCR), single-strand conformation polymorphism, and the direct sequencing of PCR-amplified fragments. The bcl-1, int-2, c-erbB-1, and c-myc loci of 15 patients were investigated using Southern blot analysis. RESULTS. A mutation of the p53 gene was detected in 5/18 patients (approximately 28%), bcl-1 locus amplification in 4/15 (approximately 26%), c-erbB-1 locus amplification in 2/15 (approximately 13%), and c-myc locus amplification in 1/15 (approximately 6%). The simultaneous presence of more than one genetic lesion was observed in four patients; two showed int-2/bcl-1 coamplification, and two int-2/c-erbB-1 coamplification, one of whom also showed a p53 gene mutation. A novel p53 mutation involving the splice acceptor site of exon 6 was detected in one patient. Two of the five patients positive for p53 mutations had clinical relapses of primary tumors. bcl-1 locus amplification only was observed in patients with lymph node metastases (4/6). All but one of the patients with molecular genetic lesions showed a peculiar infiltrating pattern. CONCLUSIONS. Overall, these results show that alterations of known protooncogenes and the p53 tumor suppressor gene are involved in a large proportion of LSCCs (11/18; approximately 60%) and may suggest that distinct molecular pathways occur in the pathogenesis of these tumors. PMID: 7882279 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 924: Oncogene. 1995 Mar 2;10(5):869-79. Loss of p53 function leads to metastasis in ras+myc-initiated mouse prostate cancer. Thompson TC, Park SH, Timme TL, Ren C, Eastham JA, Donehower LA, Bradley A, Kadmon D, Yang G. Department of Urology, Baylor College of Medicine, Houston, Texas. To study the interactions between dominantly acting oncogenes and tumor suppressor genes we used p53 'knockout' mouse urogenital sinus tissue for retroviral transduction of ras and myc in the mouse prostate reconstitution (MPR) model system. Epithelial hyperplasia was observed in all wild-type p53 MPRs with one small focal cancer and no evidence of metastasis. Prostatic cancer was found in 100% of the heterozygous and homozygous p53 mutant MPRs with metastatic deposits in 95% of the mice. The pattern of metastasis was remarkably similar to that in human prostate cancer with gross metastatic deposits in the lung, lymph nodes, bone and liver of many animals. Progression of carcinomas in the ras+myc-initiated heterozygous p53 mutant MPRs was invariably associated with either complete loss, partial deletion or loss of expression of the wild-type p53 allele. Southern blotting analysis of proviral-cellular DNA junction fragments in primary carcinomas and cell lines derived from metastatic deposits revealed that metastases do not necessarily seed out from the most abundant clone in the primary carcinoma. PMID: 7534899 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 925: Nippon Rinsho. 1995 Mar;53(3):564-7. [Molecular analysis of multiple myeloma cells] [Article in Japanese] Yasuga Y, Hirosawa S. First Department of Internal Medicine, Tokyo Medical and Dental University. Multiple myeloma (MM) is a malignant proliferation of bone marrow plasma cells. Molecular analyses of the involvement of oncogenes (c-myc, and N- and K-ras genes) and suppressor gene (p53) in pathogenesis of MM have been recently carried out. Relatively high incidence of elevated expression of c-myc mRNA have been found, although the gene rearrangements are very rare. Mutations of N- and K-ras genes have been found in about 1/3 of patients with MM. Point mutations of p53 gene were detected in about 10-20% of patients. The mutations were found in terminal or leukemic phase of the disease. These indicate that oncogenes and suppressor genes are involved in the development and progression of MM. Publication Types: Review Review, Tutorial PMID: 7699886 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 926: Oncogene. 1995 Feb 16;10(4):671-80. Transcriptional repression by the C-terminal domain of p53. Shaulian E, Haviv I, Shaul Y, Oren M. Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel. We have previously shown that monomeric p53 can transactivate target genes in vivo and that C-terminal fragments of p53 are oncogenic. To further elaborate these findings a series of C-terminal truncations of p53 was generated. The transactivation capacity and the ability of the truncated p53 to suppress oncogene-mediated transformation were studied. We found that p53 truncated at amino acid 303 (p53wtdl303) can still function in both assays, though less efficiently than full length wild type (wt) p53. Transforming C-terminal fragments inhibited transactivation induced by full length wt p53. Surprisingly, they also inhibited transactivation by wtdl303, with which they do not share any overlapping sequences. Furthermore, the C-terminal fragments repressed the transactivation domains of several viral and cellular transcriptional activators. These data raise the possibility that the C-terminal domain of p53 may compete with the p53 transactivation domain for a common basal transcription factor. PMID: 7862444 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 927: Int J Cancer. 1995 Jan 17;60(2):235-43. Modulation of cellular chemoresistance in keratinocytes by activation of different oncogenes. Sanchez-Prieto R, Vargas JA, Carnero A, Marchetti E, Romero J, Durantez A, Lacal JC, Ramon y Cajal S. Department of Pathology, Clinica Puerta de Hierro, Universidad Autonoma de Madrid, Spain. Response to chemotherapeutic agents in malignant tumors depends on many factors, most of which are as yet unknown. We investigated the correlation between the activation of different oncogenes and protein-kinase-C (PKC) modulation, and the cytotoxicity of some of the most widely used anti-cancer drugs. We transformed the murine keratinocyte cell line PAM 212, with different oncogenes (v-H-ras, v-myc and adenovirus E1a) and a mutant p53 suppressor gene (mp53). The cytotoxic effect of cisplatin (CDDP), doxorubicin (DOX) and vincristine (VCR), together with the concomitant action of modulators of PKC, TPA and staurosporine were evaluated by the crystal-violet method, thymidine incorporation and flow cytometry. We report that (a) the oncogene v-H-ras induces resistance to CDDP (> 50%), DOX (> 25%) and VCR (> 20%); (b) the E1a oncogene induces only resistance to VCR (> 40%) and marked sensitivity to CDDP and DOX; (c) the mp53 oncogene induces more resistance to VCR and insignificant resistance to the other drugs; and (d) activation of PKC by TPA increases the resistance to VCR and DOX in cells transformed by the v-H-ras, while it significantly increases the lethality with CDDP of the E1a-transformed cells. Staurosporine increases the cytoxicity of all the drugs, especially in the E1a-transformed keratinocytes. In the flow-cytometry analysis, the percentage of BUdR incorporation was related to sensitivity to anti-cancer drugs. PMID: 7829222 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 928: Blood. 1995 Jan 15;85(2):480-6. Lack of the expression of EBNA-2 and LMP-1 in T-cell neoplasms possessing Epstein-Barr virus. Suzushima H, Asou N, Fujimoto T, Nishimura S, Okubo T, Yamasaki H, Osato M, Matsuoka M, Tsukamoto A, Takai K, et al. Second Department of Internal Medicine, Kumamoto University School of Medicine, Japan. We investigated 34 cases of T-cell neoplasm [15 cases of T-cell granular lymphocytic leukemia (T-GLL), 10 cases of T-cell non-Hodgkin's lymphoma (T-NHL), six cases of T-cell chronic lymphocytic leukemia (T-CLL), and three cases of cutaneous T-cell lymphoma] to study their association with Epstein-Barr virus (EBV). In 4 (three T-NHL and one T-GLL) of 34 cases, EBV genome was detected in a single episomal form, while polyclonal EBV-DNA was detected in one (T-NHL) of the remaining cases. All three cases of T-NHL having monoclonal EBV episome showed histologically diffuse large-cell lymphoma and developed leukemic conversion. Phenotypic analysis showed that two of these four cases were CD4+, CD8-, and the remaining two cases were CD4-, CD8+. The cells from all four cases were confirmed to be in T-cell lineage by detecting the rearrangement of T-cell receptor (TCR) beta or gamma chain gene. By reverse transcription-polymerase chain reaction (RT-PCR), EBNA-1 was detected at low levels, and neither EBNA-2 nor LMP-1 were found in any of the three cases examined. Lack of the expression of EBNA-2 and LMP-1 was also confirmed by immunocytochemical staining. The cells of these four cases did not show rearrangement or overexpression of c-myc and bcl-2 genes by Southern and Northern blots, and the mutation of p53 gene was detected in only one patient. These results suggest that other latent gene products of EBV or other cellular oncogenes are involved in the development of Japanese T-cell neoplasm after EBV infection. PMID: 7812002 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 929: Blood. 1995 Jan 15;85(2):359-67. Regulation of apoptosis induced by the retinoid N-(4-hydroxyphenyl) retinamide and effect of deregulated bcl-2. Delia D, Aiello A, Formelli F, Fontanella E, Costa A, Miyashita T, Reed JC, Pierotti MA. Istituto Nazionale Tumori, European Institute of Oncology, Milan, Italy. The cancer chemopreventive retinoid N-(4-hydroxyphenyl)-all-trans retinamide (HPR) was recently shown by us to have antiproliferative and apoptotic effects on human leukemic cell lines, including those unresponsive to all-trans retinoic acid (ATRA). We have now characterized further the process of HPR-induced cell death. We report that inhibitors of RNA transcription and of protein synthesis, activators of protein kinase C (PKC), inhibitors of tyrosine kinases, Zn++, and the antioxidants acetylcysteine, ascorbic acid, alpha-tocopherol, and deferoxamine suppressed HPR-induced apoptosis. HL60 cells induced toward monocytic differentiation by 1,25 dihydroxyvitamin-D3 [1,25(OH)2D3], but not those induced toward the granulocytic differentiation by ATRA, showed reduced responses to HPR. The transport of HPR by cells with different sensitivity to the retinoid, however, was similar, even after treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), which induces unresponsiveness to HPR. The expression of the apoptosis-related genes bcl-2, p53, and c-myc was examined to determine their role in HPR-triggered cell death. The levels of bcl-2 mRNA were markedly diminished by 24 hours of HPR treatment in all cell lines except in the relatively HPR-insensitive line K422. However, probably because of its long half-life, bcl-2 protein levels were either unchanged or only slightly decreased. Downregulation of p53 mRNA was also observed within 24 hours of HPR exposure in NB4 but not K422 cells, but no changes in the amount of p53 protein were found. Suppression of c-myc transcription was observed in all cells except K422. The protective role of bcl-2 on cell death by HPR was investigated in HL60 as well as 697 pre-B leukemia and Jurkat T-acute lymphocytic leukemia (T-ALL) cells constitutively expressing high levels of bcl-2 proteins due to gene transfer manipulation. Compared with control cells, the onset of apoptosis in these cells with deregulated bcl-2 production was delayed by at least 24 hours. These findings establish that cell death by HPR requires RNA transcription and protein synthesis and is regulated by the activation of PKC. Although changes in bcl-2, p53, and c-myc expression are found in cells treated with HPR, the time-course of these events suggests that HPR-triggered apoptosis is not directly controlled by these genes. Finally, while ectopic overexpression of bcl-2 does not protect cells from death by HPR, it markedly delays its onset.(ABSTRACT TRUNCATED AT 400 WORDS) PMID: 7811993 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 930: Urol Res. 1995;23(5):293-300. Inactivation of tumor suppressor genes and deregulation of the c-myc gene in urothelial cancer cell lines. Grimm MO, Jurgens B, Schulz WA, Decken K, Makri D, Schmitz-Drager BJ. Department of Urology, Heinrich-Heine University, Dusseldorf, Germany. Recent investigations have demonstrated p53 and Rb alterations in a subset of transitional cell carcinoma (TCC). Further genetic changes during tumor progression include overexpression of the c-myc gene in a significant number of mainly invasive bladder tumors. To study the possible interactions between these genes in TCC, urothelial cancer cell lines were chosen as an in vitro model. Expression and mutation of p53 was studied in 15 bladder cancer cell lines by immunocytochemistry, Western blot, polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing of double stranded PCR products of exons 4, 5, 7 and 8 of genomic DNA. C-myc expression and gene structure were studied using Northern and Southern blot techniques Rb protein expression was analyzed by Western blot. Twelve of 15 cell lines showed either p53 mutations or abnormal protein expression. Consistent with previous studies, five cell lines did not express Rb protein. None of the cell lines studied retained both tumor suppressor genes in a functional form. The c-myc gene appeared to be intact in all cell lines and copy numbers were close to normal. Northern analysis demonstrated that all cell lines expressed c-myc mRNA but evidence for altered regulation was found in at least two cell lines. Our data suggest that amplification or translocation are not the underlying mechanism for c-myc overexpression in urothelial tumors. No correlation between loss of Rb protein and c-myc expression was observed. The results presented here for the cell lines match well those obtained in vivo. Thus, these cell lines may provide a suitable model for further analysis of molecular alterations in urothelial cancer. PMID: 8839385 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 931: Cancer Surv. 1995;25:315-34. Molecular genetics of sporadic and familial breast cancer. Jones KA, Brown MA, Solomon E. Somatic Cell Genetics Laboratory, Imperial Cancer Research Fund, London. Molecular genetic analysis of breast cancers indicates that the mechanisms underlying tumorigenesis are complicated. Many oncogenes and tumour suppressor genes have been implicated, encoding proteins that are important at many levels of cell regulation, from cell surface molecules responding to external signals (eg ERBB2) to nuclear factors controlling gene transcription (eg TP53, MYC). Several correlations have been found between certain genetic events and clinical outcome and have therefore proved useful prognostic indicators. The mapping and cloning of genes important in familial breast cancers (eg BRCA1) have provided the essential tools for pinpointing the genes that may be critical in early stage breast cancer as well as for developing genetic tests for predicting carrier status in breast cancer families. Clarification of the molecular consequences of mutation in breast cancer associated genes is beginning to address the factors that drive a normal breast cell to change into a breast cancer cell. However, these studies are still in their infancy, and considerable research will be required to complete the picture. Publication Types: Review PMID: 8718525 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 932: Cancer Surv. 1995;25:173-94. The genetics of programmed (apoptotic) cell death. Lin X, Denmeade SR, Isaacs JT. Johns Hopkins University School of Medicine, Johns Hopkins Oncology Center, Baltimore, MD 21231-1001, USA. The genetic pathway for the activation and completion of programmed death of cells is as complex and well regulated as the pathway for cell proliferation. The identification of both the genetic elements in the signal transduction pathway involved with the initiation of programmed cell death, as well as the cellular machinery involved with DNA and cellular fragmentation into apoptotic bodies, is developing rapidly. Attempts at understanding how these elements are co-ordinated into a temporally discrete series of metabolic steps is only just beginning. This research not only will be fruitful from a basic science standpoint, but should also identify new approaches for cancer chemoprevention and therapy. Publication Types: Review PMID: 8718518 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 933: Ann Oncol. 1995;6 Suppl 3:S3-8. Molecular genetic tumor markers in the early diagnosis and screening of non-small-cell lung cancer. Jacobson DR, Fishman CL, Mills NE. Department of Medicine, Kaplan Cancer Center, New York University Medical Center, New York, USA. BACKGROUND: Little progress has been made in decreasing lung cancer mortality by applying conventional methods to early diagnosis and screening. Recent advances in molecular oncology, however, have provided tools which may be of use in this area. Many genes involved in controlling cell growth and differentiation are abnormal in lung cancer cells. Such genes include K-ras, p53, rb, myc, her2/neu, and probably one or more tumor suppressor genes on chromosome 3p. The involvement of these genes in lung cancer is reviewed. The K-ras oncogene contains a mutation in codon 12 in many cases of non-small-cell lung cancer, particularly adenocarcinoma, and is thus a potentially useful lung cancer tumor marker. DESIGN; We have developed a highly sensitive, simple assay for ras mutations, and applied it to bronchoalveolar lavage fluid obtained from patients undergoing evaluation for suspected lung cancer. RESULTS: In many cases, the ras assay was more sensitive than routine cytology and histopathology, demonstrating that this is a potentially clinically useful assay. CONCLUSION: Molecular genetic tumor markers, including mutations in ras and other genes, and/or immunohistochemical tumor markers, may provide tools which can be applied to bronchoalveolar lavage fluid or sputum, for use in diagnostic tests and in screening programs. The use of such markers may lead to decreased lung cancer mortality. Publication Types: Case Reports Review Review, Tutorial PMID: 8616111 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 934: Cell Mol Biol Res. 1995;41(3):161-6. Dominant oncogenes, tumor suppressors, and radiosensitivity. Chiarugi V, Magnelli L, Cinelli M, Turchetti A, Ruggiero M. Laboratory of Molecular Biology, University of Firenze, Italy. A variety of conflicting results appeared in the literature concerning the effect of dominant oncogenes on the sensitivity to irradiation and to anticancer agents in a number of cell lines of human and animal origin. In this report we provide evidence supporting the hypothesis that the tumor suppressor gene p53 and the apoptosis suppressor gene bcl2 modulate the effect of dominant oncogenes and that the effect of dominant oncogenes on resistance or sensitivity is dependent on the balance between the expression of p53 and bcl2. Publication Types: Review Review, Tutorial PMID: 8589756 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 935: J Neurooncol. 1995;24(1):39-45. Prognostic implications of chromosome 17p deletions in human medulloblastomas. Batra SK, McLendon RE, Koo JS, Castelino-Prabhu S, Fuchs HE, Krischer JP, Friedman HS, Bigner DD, Bigner SH. Department of Pathology, Duke University Medical Center, Durham, North Carolina, USA. DNA derived from medulloblastoma biopsies was analyzed to determine if deletions of the 17p region, mutations of the TP53 gene, or amplification of the c-myc, N-myc, EGFR (epidermal growth factor receptor), or MDM2 (murine double-minute-2) genes was indicative of a poor prognosis. Loss of heterozygosity for 17p, observed in 8/28 (29%) paired samples, was associated with a shortened survival period (p = 0.045 by the logrank test). TP53 mutations occurred in 2/46 (4.3%) tumor samples. c-myc Amplification was seen in 3/43 (6.9%) cases, while none of the tumors contained amplified N-myc, EGFR, or MDM2 genes. These results demonstrate that, while only rare medulloblastomas contain TP53 gene mutations or amplification of the c-myc gene, loss of heterozygosity on chromosome 17p is indicative of a significantly worse prognosis among patients with these tumors. Further, these results provide a strong impetus for a prospective analysis of loss of heterozygosity in a cooperative group setting, which would include tumor staging, a selection of treatment modalities, and multivariate analyses. PMID: 8523074 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 936: J Cancer Res Clin Oncol. 1995;121(2):98-102. 6-Amino-6-deoxyascorbic acid induces apoptosis in human tumor cells. Grdisa M, Kralj M, Eckert-Maksic M, Maksic ZB, Pavelic K. Department of Molecular Medicine, Ruder Boskovic Institute, Zagreb, Croatia. 6-Amino-6-deoxyascorbic acid was found to inhibit human tumor cell growth. The antitumor effect depends on the tumor type and concentration of the acid. After cell treatment with 6-amino-6-deoxyascorbic acid, drastic morphological changes were found. Although image analysis did not show a difference in p53 and c-myc gene expression, the appearance of chromatin aggregation and DNA fragmentation points to apoptosis or programmed cell death. PMID: 7883782 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 937: No Shinkei Geka. 1995 Jan;23(1):7-15. [Gene therapy for brain tumors: induction of apoptosis and immunogenic modulation in glioma cells (series 5)] [Article in Japanese] Asai A. Department of Neurosurgery, Faculty of Medicine, University of Tokyo. Publication Types: Review Review, Tutorial PMID: 7845524 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 938: Cancer Treat Res. 1995;74:17-42. Molecular phenotyping of head and neck cancer. Shin DM, Tainsky MA. Department of Thoracic/Head and Neck Medical Oncology, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA. Publication Types: Review PMID: 7779615 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 939: Curr Top Microbiol Immunol. 1995;200:137-46. Death genes in T cells. Woronicz J, Calnan B, Winoto A. Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200, USA. Publication Types: Review Review, Tutorial PMID: 7634828 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 940: Recent Results Cancer Res. 1995;139:249-61. bcl-1, bcl-2, p53, c-myc, and lyt-10 analysis in cutaneous lymphomas. Garatti SA, Roscetti E, Trecca D, Fracchiolla NS, Neri A, Berti E. Laboratorio di Ematologia Sperimentale e Genetica molecolare, Istituto di Scienze Mediche, Milan, Italy. In the present study we investigated the pathogenetic role of c-myc, bcl-2, and lyt-10 oncogenes, bcl-1 locus, and p53 suppressor gene in a representative panel of cutaneous lymphomas, including 25 cases of cutaneous B cell lymphoma (CBCL) and 29 cases of cutaneous T cell lymphoma (CTCL). In our analysis four cases of CBCL were found rearranged for bcl-2 and two for the bcl-1 locus. Two cases of CTCL and one case of CBCL were found rearranged for lyt-10. No rearrangements of c-myc oncogene were found in CBCL. Analysis of p53 gene showed mutation only in one case of mycosis fungoides in tumoral stage, at codon 163 of p53 gene (TAC-->CAC; Tyr--> Asp). Our data suggest that in primary CBCL bcl-2 oncogenes and bcl-1 locus are rarely involved. Furthermore, in primary CTCL p53 gene is not affected at significant frequency. The occurrence of p53 mutation in a patient affected by mycosis fungoides in tumoral stage may represent an involvement of p53 gene in tumor progression of CTCL, a finding observed in several types of human cancer. PMID: 7597296 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 941: Eur J Cancer. 1995;31A(4):560-4. Genetic alterations associated with metastatic dissemination and chemoresistance in neuroblastoma. Benard J. Laboratory of Clinical & Molecular Pharmacology, Institut Gustave Roussy, Villejuif, France. Knowledge about genetic alterations specific to the metastatic process and chemoresistance in neuroblastoma is progressing steadily. Low or no CD44 expression, increased NM23 expression and specific mutations of the 5' coding regions of NM23 are distinct features of aggressive, metastatic neuroblastoma. MYCN down-regulates Class I HLA antigen expression in many neuroblastoma cell lines and, in turn, may be regulated by a suppressor gene. The MYCN amplified human neuroblastoma cell line, IGR-N-91, established in vitro, metastasises in the nude mouse and has exhibited co-activation of MYCN and PGY1, resulting from direct activation of the oncoprotein on the PGY1 promoter. In this model, the MYCN product activates angiogenesis, the dissemination process and chemoresistance via specific genes (PGY1 and GST3). MYCN, like the BCL-2 and TP53 products, may also play a key role in apoptosis. The implication of these genes in the potential for metastasis and chemoresistance in neuroblastoma is discussed. Publication Types: Review Review, Tutorial PMID: 7576968 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 942: Cancer Surv. 1995;24:19-42. Are CD44 variant isoforms involved in human tumour progression? Gunthert U, Stauder R, Mayer B, Terpe HJ, Finke L, Friedrichs K. Basel Institute for Immunology, Switzerland. The transmembrane glycoprotein CD44 exists in a variety of isoforms generated by alternative splicing of the pre-mRNA. In a rat metastasis model, certain variant isoforms (containing exon 6v) are causally involved in lung metastasis formation. We have summarized the data obtained to date on the expression of CD44 variant isoforms in human tumour progression. In non-Hodgkin lymphomas, expression of exon 6v containing isoforms is an independent prognostic factor indicating an adverse prognosis. Upregulation of exon 9v containing isoforms in gastric and renal cell carcinomas relates to a poor prognosis of patients. In colorectal carcinomas, CD44-9v isoforms are strongly expressed already in early adenomas; CD44-6v isoforms are upregulated in late adenomas along with ras and TP53 mutations. No expression of variant isoforms has been detectable in neuroblastomas, but significant downregulation of CD44s correlates inversely with tumour progression and N-myc amplification. Only in breast carcinoma has no correlation of CD44 expression with survival or any other prognostic marker been established. Evaluation of CD44 isoform expression by immunohistochemistry in cases of non-Hodgkin lymphoma, gastric, colon and renal cell carcinomas, as well as neuroblastomas, may be a useful diagnostic parameter indicating invasive processes. Publication Types: Review Review, Tutorial PMID: 7553660 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 943: Am J Pathol. 1995 Jan;146(1):67-74. Detection of apoptosis and expression of apoptosis-related proteins during human intrahepatic bile duct development. Terada T, Nakanuma Y. Second Department of Pathology, Kanazawa University School of Medicine, Japan. We investigated apoptosis by nick end labeling and the expression of apoptosis-related proteins by immunohistochemistry in fetal development of human intrahepatic bile ducts and hepatocytes. During intrahepatic bile duct development, apoptosis was present at all stages, and its positive ratio was high in the remodeling ductal plate, moderate in the ductal plate, and relatively low in remodeled ducts. The cell proliferative activity as determined by proliferating cell nuclear antigen was also high in the remodeling ductal plate, and relatively low in the ductal plate and remodeled ducts. fas antigen and c-myc protein were constantly positive in the ductal plate, remodeling ductal plate and remodeled ducts. Bcl-2 protein was negative or faintly positive in the ductal plate and remodeling ductal plate, but was apparently positive in remodeled ducts. Lewisy as detected by the BM-1 antibody was present in the ductal plate, remodeling ductal plate, and remodeled ducts. p53 protein was not found in any cell types in the liver development. During hepatocyte development, many apoptotic and proliferating cell nuclear antigen-positive hepatocytes were noted. The developing hepatocytes expressed c-myc protein and fas antigen. Bcl-2 protein and Lewisy antigen were also weakly positive in the developing hepatocytes. These findings showed that balanced cell proliferation and apoptosis are involved in the normal development of intrahepatic bile ducts and hepatocytes, and suggest that c-myc protein, fas antigen, Bcl-2 protein, and Lewisy antigen modulate apoptosis of fetal intrahepatic biliary cells and hepatocytes, probably by stimulative (c-myc protein and fas and Lewisy antigens) or inhibitory (Bcl-2 protein) effects. PMID: 7531950 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 944: Biochim Biophys Acta. 1994 Dec 30;1198(2-3):113-30. Somatic genetic changes in human breast cancer. Devilee P, Cornelisse CJ. Department of Pathology, University of Leiden, The Netherlands. Quantitative imbalance in chromosomal material relative to the normal diploid situation is the most conspicuous genetic change in breast tumors, affecting virtually all chromosomes in varying frequencies. This imbalance is reflected by deviant DNA stemlines observed in DNA flow cytometry analysis, by numerical chromosome abnormalities in karyotype analysis and by loss of heterozygosity in DNA polymorphism studies. Gene amplification might be caused by the same genetic mechanisms that cause these chromosomal abnormalities [134]. The number of known genes for which there is now good evidence for their role in the development of breast cancer is still limited, and basically restricted to TP53 and ERBB2. Clearly, the estrogen receptor, not discussed here, can be conjectured to be of importance in breast cancer development, yet the significance of the reported sequence variants [157] for hormone-independent growth is presently undetermined [158]. For many others, such as MYC, CCND1, EMS1, EGF, RB1, NME, DCC and prohibitin, the evidence is still largely circumstantial, or obtained only by in vitro studies on breast cancer cell lines. In many cases of chromosomal imbalance and certainly those affecting whole chromosomes or chromosome arms, it is unclear what their effect on tumor growth will be, because multiple potential candidate genes are located in the affected region. In addition, it is obvious that multiple chromosomes are affected simultaneously in a single tumor, but that the total set of chromosome changes varies in different tumors. This intra- and intertumor heterogeneity of chromosome involvement suggests that an unknown number of the observed abnormalities are not important for tumor development, but merely result from genetic instability. On the other hand, there is accumulating evidence, particularly from flow cytometry and allelotype studies reviewed here, to suggest that the genetic evolution associated with tumor development and progression does reach a stage of equilibrium despite the presence of extensive tumor heterogeneity. The number of genetic events found per tumor raises the question whether each event of heterozygosity loss represents the second step in the inactivation of a tumor suppressor gene. Also, LOH observed with polymorphic markers can sometimes be interpreted as allelic copy number gain instead of loss. Possibly, some of these allelic imbalances contribute to the tumorigenic process simply because they create a dosage effect in certain gene products [2]. This supposes that the sole presence of allelic imbalance at certain chromosomes is sufficient to provide selective growth advantage in certain cases.(ABSTRACT TRUNCATED AT 400 WORDS) Publication Types: Review PMID: 7819270 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 945: Proc Natl Acad Sci U S A. 1994 Dec 20;91(26):12967-71. A role for deregulated c-Myc expression in apoptosis of Epstein-Barr virus-immortalized B cells. Cherney BW, Bhatia K, Tosato G. Laboratory of Immunology, Food and Drug Administration, National Institutes of Health, Bethesda, MD 20892. When deprived of autocrine growth factors, Epstein-Barr virus (EBV)-immortalized B cells stop growing and die. In this study, we show that death of EBV-immortalized cells deprived of autocrine growth factors occurred by apoptosis. Cycloheximide, a protein synthesis inhibitor, inhibited apoptosis, suggesting that de novo protein synthesis is required. Because p53, Bcl-2, and c-Myc were previously implicated in the induction or prevention of apoptosis in other systems, we assessed their possible involvement here. Unlike normal cells that respond to growth factor deprivation by down-regulating c-Myc expression, EBV-immortalized cells continued to express c-Myc, p53, and Bcl-2 at levels comparable to those measured prior to starvation. Consistent with data demonstrating that c-Myc expression is sufficient to drive quiescent cells into the cell cycle, autocrine growth factor-deprived EBV-immortalized cells did not undergo growth arrest but rather continued to proliferate until death, which occurred randomly throughout the cell cycle. In contrast to EBV-immortalized B cells, normal peripheral blood B cells activated in vitro with anti-CD40 monoclonal antibody and interleukin 4 rapidly down-regulated c-Myc expression and underwent growth arrest in response to growth factors and serum deprivation. These findings demonstrated that c-Myc expression is deregulated in EBV-immortalized cells. Addition of antisense oligonucleotides to c-Myc specifically promoted the survival of starved EBV-immortalized cells and suppressed growth of nonstarved EBV-immortalized cells. Thus, deregulated expression of c-Myc in EBV-immortalized cells promotes proliferation and apoptosis following autocrine growth factor deprivation. PMID: 7809156 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 946: Ann N Y Acad Sci. 1994 Dec 15;747:172-82. Transcription factors as molecular mediators in cell death. Soares HD, Curran T, Morgan JI. Roche Institute of Molecular Biology, Roche Research Center, Nutley, New Jersey 07110. Publication Types: Review PMID: 7531406 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 947: Genes Dev. 1994 Dec 1;8(23):2817-30. Myc-mediated apoptosis requires wild-type p53 in a manner independent of cell cycle arrest and the ability of p53 to induce p21waf1/cip1. Wagner AJ, Kokontis JM, Hay N. Ben May Institute, University of Chicago, Illinois 60637. Deregulated expression of the c-myc proto-oncogene can lead to apoptosis under certain physiological conditions. By introducing a conditionally active Myc allele into primary embryo fibroblasts null for p53, and into fibroblasts without endogenous p53 expression but ectopically expressing a temperature-sensitive p53 allele, we show that expression of wild-type p53 is required for susceptibility to Myc-mediated apoptosis. Although ectopic expression of wild-type p53 blocked cells in the G1 phase of the cell cycle, G1 arrest by isoleucine starvation, in a manner independent of p53, did not confer susceptibility to apoptosis. Thus, growth arrest per se is not sufficient to induce Myc-mediated apoptosis; instead, a property intrinsic to p53 is specifically required. Moreover, apoptosis did not require induction of p53 target proteins, including the cyclin-dependent kinase inhibitor p21waf1/cip1. Therefore, the role of p53 in apoptosis may be distinct from its role in cell cycle arrest. PMID: 7995520 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 948: Mol Cell Biol. 1994 Dec;14(12):7805-15. Transactivation of the human p53 tumor suppressor gene by c-Myc/Max contributes to elevated mutant p53 expression in some tumors. Roy B, Beamon J, Balint E, Reisman D. Department of Biological Sciences, University of South Carolina, Columbia 29208. Elevated levels of mutant forms of the p53 tumor suppressor are a hallmark of many transformed cells. Multiple mechanisms such as increased stability of the protein and increased transcription of the gene can account for elevated p53 expression. Recent findings indicate that c-Myc/Max heterodimers can bind to an essential CA(C/T)GTG-containing site in the p53 promoter and elevate its expression. We have addressed the possibility that elevated mutant p53 expression is due to deregulated c-Myc expression. Here we demonstrate that the human p53 promoter is transactivated by high c-Myc expression and repressed by high Max expression. In examining the relative levels of c-Myc and p53 in human Burkitt's lymphomas and other B-lymphoid lines, we found that there is a correlation between the levels of c-Myc protein and p53 mRNA expression. In particular, cells that express very low levels of c-Myc protein also express low levels of p53 mRNA, while cells that express high levels of c-Myc tend to express high levels of p53 mRNA. To determine whether the p53 gene can be a target for c-Myc in vivo, we assayed the effects of antisense c-myc RNA on the levels of endogenous p53 mRNA. The results indicate that the presence of antisense c-myc RNA leads to a reduction in the levels of c-Myc protein, p53 mRNA, and expression from the p53 promoter. Taken together, our findings support a direct role for c-Myc in elevating expression of the mutant p53 gene in some tumors. PMID: 7969121 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 949: Nippon Rinsho. 1994 Dec;52(12):3319-29. [Tumor suppressor genes] [Article in Japanese] Kuchino Y. Cell fusion experiments performed by Harris et al. informed that tumor suppressor genes are inactivated in malignant cells. Inactivation of tumor suppressor genes induced by genetic alteration such as point mutation and deletion leads to disturbance in the control of cell proliferation resulting in deregulated growth of normal cells. Recently, many challenges of scientists including clinicians trying to direct the studies of tumor suppressors toward cancer therapy have been stimulated. For that purpose, it is important to understand the molecular mechanism in which change of normal phenotypes into tumor take place. In this review, recent topics on tumor suppressors such as Rb, p53, Wt1, APC, NF1, s-Myc and H19 are included to discuss their significance and function. Publication Types: Review Review, Tutorial PMID: 7853729 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 950: Bull Cancer. 1994 Dec;81 Suppl 2:105s-111s. [Drug resistance, oncogenes, and anti-oncogenes in epithelial tumors] [Article in French] Riva-Lavieille C. Institut Albert-Bonniot, Universite Joseph-Fourier, Grenoble, France. Twenty four squamous cell carcinomas of the head and neck (HNSCC) of stage II to IV were evaluated for the expression of potential markers such as oncogenes and tumor suppressor genes in drug-resistance behavior. We have analysed the c-myc, c-jun, c-raf and N-ras and p53 expression in total RNA preparation from tumor biopsies obtained before treatment. The patients underwent chemotherapy including 5-fluorouracil and cisplatinum. No significant differences in c-raf and N-ras expression were found in responding or resistant patients. However, resistance to chemotherapy was associated with low expression of c-myc (P < 0.025) or high expression of c-jun (P < 0.001). In addition, p53 mRNA pre-therapeutic level was increased in unresponsive patients to chemotherapy (P < 0.05). Therefore, analysis of the expression of c-myc, c-jun oncogenes and p53 tumor suppressor gene in tumor cells before initiation of therapy may define a subset of patients with potentially better prognosis. PMID: 7727855 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 951: Immunol Rev. 1994 Dec;142:127-39. Analysis of the role of bcl-2 in apoptosis. Hawkins CJ, Vaux DL. Walter & Eliza Hall Institute for Medical Research, Victoria, Australia. Cells undergo apoptosis in response to a wide range of stimuli, and this response may represent an ancient defence mechanism against pathogens. Bcl-2 is able to prevent apoptosis in many cases. Although blocking cell suicide is not directly oncogenic, enforced bcl-2 expression can lead to cancer by lengthening the life-span of cells, during which time secondary changes, such as activation of additional oncogenes like c-myc, can occur. Bcl-2 cannot block apoptosis of target cells by cytotoxic T lymphocytes. Thus cytotoxic T cells are able to fight viruses that carry anti-apoptosis genes that resemble bcl-2. Genes involved in the regulation of mammalian apoptosis are similar to those that mediate programmed cell death in C. elegans. By studying cell death genes in viruses and worms as well as mammals, we will learn more about this fascinating process. Publication Types: Review PMID: 7698791 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 952: Gan To Kagaku Ryoho. 1994 Nov;21(15):2549-54. [Advances in pathobiological research on lung carcinoma] [Article in Japanese] Noguchi M. Dept. of Pathology, National Cancer Center Research Institute. Histological examination revealed that many peripheral type papillary adenocarcinomas appear to develop from atypical adenomatous hyperplasia (AAH), which can be called adenoma or in situ adenocarcinoma, and progress stepwise. Molecular-biologically, loss of heterozygosities of 3, 11 and 17 chromosomes, point mutation of ras oncogene and p53 anti-oncogene, amplification of myc oncogene, and overexpression of erbB2 oncogene are related to lung cancer development. Especially, ras and p53 gene abnormalities are closely associated with poor prognosis of lung adenocarcinoma. Future molecular-biological examinations should focus on AAH and/or early stage adenocarcinoma of the lung, in order to clarify the gene abnormality at the early stage of lung carcinogenesis. Publication Types: Review Review, Tutorial PMID: 7979412 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 953: Cancer Res. 1994 Nov 1;54(21):5584-92. p53 gene dosage modifies growth and malignant progression of keratinocytes expressing the v-rasHa oncogene. Weinberg WC, Azzoli CG, Kadiwar N, Yuspa SH. Laboratory of Cellular Carcinogenesis, National Cancer Institute, Bethesda, Maryland 20892. Epidermal keratinocyte cultures were established from newborn mice expressing a null mutation in the p53 gene to explore the contribution of p53 to epidermal growth regulation and neoplasia. Keratinocytes were initiated by transduction with a replication-defective retrovirus encoding the v-rasHa oncogene and grafted onto nude mouse hosts. Tumors arising from keratinocytes heterozygous or null for functional p53 in the presence of v-rasHa have growth rates approximately 5-fold higher than those derived from p53(+/+) controls and rapidly form carcinomas, in contrast to the benign phenotype observed in p53(+/+)/v-rasHa grafts. In vitro, p53-deficient keratinocytes with and without v-rasHa expression display decreased responsiveness to the negative growth regulators transforming growth factors beta 1 and beta 2. In combination with v-rasHa, p53-deficient keratinocytes also exhibit decreased responsiveness to elevated Ca2+. These differences between genotypes cannot be attributed to changes in transforming growth factor beta receptor types present or altered levels of epidermal growth factor receptor and are independent of c-myc transcript levels. mRNA expression for the p-53 inducible protein WAF1 correlates with p53 gene dosage, but low levels are still detectable in p53(-/-) keratinocytes. The altered responsiveness of p53 deficient keratinocytes to negative growth regulators may provide a growth advantage to such cells in vivo and render them more susceptible to genetic alterations and malignant conversion. PMID: 7923201 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 954: Cytometry. 1994 Nov 1;17(3):237-45. Flow cytometric quantitation of C-myc and P53 proteins in bovine papillomavirus type 1-transformed primary mouse fibroblasts. Agrawal RS, Agrawal YP, Mantyjarvi RA. Department of Clinical Microbiology, University of Kuopio, Finland. Bovine papillomavirus type 1 (BPV-1)-transformed mouse fibroblast cell lines were analyzed via flow cytometry (FCM) for expression of p53 and c-myc proteins along with their DNA content. In comparison to the nontransformed control cell line, significantly elevated levels of both the p53 and the c-myc protein were present in some but not all of the transformed cell lines. Quantitation of p53 and c-myc proteins in cell lines containing BPV-1 DNA revealed that the tumorigenic cell lines expressed higher levels of both the p53 (P = 0.0034; Mann-Whitney U test) and the c-myc protein (P = 0.0039; Mann-Whitney U test) as compared to the nontumorigenic cell lines. On average, at least 9,000-10,000 p53 or c-myc protein molecules per cell were detected in the transformed tumorigenic cell lines. These results show that quantitative FCM can be reliably used to detect very low levels (3,000 molecules per cell) of specific protein, and FCM is a useful tool to study the virus-induced changes in the levels of nuclear proteins within a cell population and in tumorigenesis. PMID: 7851159 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 955: Cell Growth Differ. 1994 Nov;5(11):1153-8. Modulation of tumor immunogenicity of rat glioma cells by s-Myc expression: eradication of rat gliomas in vivo. Asai A, Miyagi Y, Hashimoto H, Lee SH, Mishima K, Sugiyama A, Tanaka H, Mochizuki T, Yasuda T, Kuchino Y. Biophysics Division, National Cancer Center Research Institute, Tokyo, Japan. The Myc family proteins represented by c-Myc are thought to play a crucial role in cellular proliferation, differentiation, transformation, and apoptosis. In this study, we demonstrated the novel role for a Myc family protein in elicitation of immunogenic phenotypes in tumor cells. Injection of rat 9L or C6 glioma cells, together with the s-myc gene linked to the cytomegalovirus promoter, completely prevented formation of both brain tumors and s.c. tumors derived from the parental glioma cells. However, introduction of the s-myc gene had no inhibitory effect on development of B104-derived neuroblastoma. In addition, unlike the s-myc gene, injection of the c-myc or wild type p53 (wt-p53) gene together with glioma cells did not modulate the tumor immunogenicity and resulted in formation of gliomas in the animals. These findings suggest that s-Myc expression may stimulate the presentation of a tumor antigen common to 9L and C6 cells to T lymphocytes and augment the activity of the host immune system, resulting in prevention of glioma formation in vivo. This success in tumor eradication indicates the possibility of application of the s-myc gene for gene therapy of human brain tumors. PMID: 7848917 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 956: Jpn J Cancer Res. 1994 Nov;85(11):1105-11. Characteristics of human hepatocellular carcinoma cell lines (Hep-KANO) derived from a non-hepatitic, non-cirrhotic hepatitis B virus carrier. Baba M, Hasegawa H, Nakayabu M, Tamaki S, Watanabe S, Shima T, Suzuki S, Kusano I, Kamada N. Third Department of Internal Medicine, Mie University School of Medicine, Tsu. We have established two cell lines of hepatocellular carcinoma [Hep-KANO, clone 1 (CL-1) and clone 2 (CL-2)] from tissue obtained at autopsy of a hepatitis B virus (HBV) carrier without histological signs of hepatitis or liver cirrhosis. These cell lines differed considerably from each other in morphology, proliferation pattern, alpha-fetoprotein secretion, albumin synthesis, cytokine secretion, modal chromosome number and transplantability to nude mice. Histologic examinations also revealed differences between them. Amplification of N-myc, L-myc, H-ras, K-ras, N-ras, c-erb-B and c-erb-B-2 and rearrangement of p53 were not found in either of the cell lines. However, CL-1 and CL-2 showed an identical HBV-DNA integration pattern. A 4-fold amplification of c-myc was observed in CL-1, but not in CL-2. Hep-KANO cell lines, CL-1 and CL-2 may be useful in clarifying the question of whether hepatocarcinogenesis is directly caused by HBV infection. PMID: 7829395 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 957: In Vivo. 1994 Nov-Dec;8(5):665-73. Relation of apoptosis to cancer therapy. Milas L, Stephens LC, Meyn RE. Department of Experimental Radiotherapy, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA. Apoptosis, or programmed cell death, is a mode of cell death characterized by distinctive biochemical and morphological features that include endonuclease activation, chromatin condensation and margination, and cellular shrinkage and fragmentation. Its role is homeostatic regulation essential in the maintenance of renewable tissues; the process is controlled by the interaction of genes and tissue-specific hormones or growth factors. A number of apoptosis-regulating genes have recently been discovered including bc1-2, c-myc, and p53. Recent experimental evidence suggests that apoptosis plays an important role in regulation of tumor growth and tumor response to various forms of cancer therapy, including radiotherapy and chemotherapy. Apoptosis develops rapidly, within hours, after cytotoxic treatments and is dose dependent. The apoptotic response correlates well with the antitumor efficacy of radiation and chemotherapy, which makes it a candidate predictor of tumor treatment response. Tumors vary in their apoptotic response to cytotoxic agents, with carcinomas being more responsive than sarcomas. In addition to this intertumor heterogeneity, there is also significant intratumor heterogeneity in apoptosis induction, consistent with the idea that the propensity for apoptosis is genetically regulated. Regulating apoptosis might be an effective way to improve tumor therapy; therapeutic gain would be achieved by increasing apoptotic response of tumors or by inhibiting apoptotic response of normal tissues. Publication Types: Review Review, Tutorial PMID: 7727712 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 958: Zhonghua Zhong Liu Za Zhi. 1994 Nov;16(6):407-10. [Alterations of oncogenes in human fetal esophageal epithelium induced by N-methylbenzylnitrosamine (NMBzA)] [Article in Chinese] Guo YJ, Lu SX, Liang YY. Cancer Institute, Chinese Academy of Medical Sciences Peking Union of Medical College, Beijing. Epidemiological investigation showed that N-methylbenzylnitrosamine (NMBzA) has been associated with increased incidence of esophageal cancer (EC) in Linxian county, a high incidence area. In present study, our results indicate that NMBzA can induce amplification and over-expression of EGFr gene in human fetal esophageal epithelium (HFE) treated with NMBzA for 24 hours as shown by southern blot assay and immunohistochemistry. The papillary hyperplasia was induced in HFEs that cultured with NMBzA for 1 to 3 weeks. Amplification of c-myc and int-2 gene in HFEs treated by NMBzA for 1 week and 3 weeks was found, respectively. Deletions of p53 and Rb gene were found in human fetal esophageal carcinomas induced by NMBzA. Overexpression of p53 protein in human fetal esophageal carcinomas detected by immunohistochemical methods indicates that p53 gene mutation(s) may be occured. The HFE explants treated in vitro with NMBzA for 3 weeks were inoculated subcutanously into balb/c nude mice. No tumor was found in 5 months after inoculation, suggesting that only changes of oncogene(s) are insufficient to induce full transformation. Other genetic alterations (such as functional inactivation of Rb or/and p53 tumor suppressor genes) may be necessary in the further progression of malignant lesions. PMID: 7720492 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 959: Pigment Cell Res. 1994 Oct;7(5):348-53. P53 mutation and c-fos overexpression are associated with detection of the antigen VLA-2 in human melanoma cell lines. Kroumpouzos G, Eberle J, Garbe C, Orfanos CE. Department of Dermatology, University Medical Center Steglitz, Free University of Berlin, Germany. In this study, we examined the expression of c-fos, c-myc, mutant c-Ha-ras and mutant p53 proteins in three normal human melanocyte cell lines and the following 12 melanoma cell lines: M5, Mewo, A375, Bro, Mel 2a, O-Mel II, IgR 39, SkMel-13, -19, -28 Mel-57 and NKI-4, using an immunohistochemical assay (APAAP). An effort was made to correlate oncogene expression with growth parameters, differentiation antigens (HMB-45, vla-2, k.1.2.58, HLA-DR, HLA-I), and pigmentation. All melanocyte cell lines were negative for the oncogenes examined, whereas six of the melanoma cell lines were found also positive (three for c-fos, two for c-myc, one for c-Ha-ras, and four for p53). Three melanoma cell lines expressed one oncogene and three the combination c-fos/p53. These three melanoma cell lines were positive for the "late" tumor progression marker A. 1.43 (vla-2 adhesion molecule) and negative for the differentiation marker k. 1. 2. 58. Positivity for A. 1. 43 combined with negative staining for k. 1. 2. 58 was found in six out of the 12 cell lines. The observed oncogene expression correlated neither with growth parameters nor melanin content. The present findings revealed a coexpression of mutant p53 and c-fos proteins being associated with a highly malignant phenotype in melanoma cell lines. Further studies are necessary to clarify the significance of the above findings. PMID: 7886007 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 960: Arthritis Rheum. 1994 Oct;37(10):1415-20. Autoimmune disease. A problem of defective apoptosis. Mountz JD, Wu J, Cheng J, Zhou T. Multipurpose Arthritis and Musculoskeletal Disease Center, University of Alabama at Birmingham. Human autoimmune diseases share the common feature of an imbalance between the production and destruction of various cell types including lymphocytes (SLE), synovial cells (RA), and fibroblasts (scleroderma). Patients with SLE have increased levels of soluble Fas that inhibit proper apoptosis of lymphocytes. In animal models of autoimmune diseases, mutations of genes involved in apoptosis including Fas, Fas ligand, and the hematopoietic cell phosphatase gene have been identified. Oncogenes, including bcl-2, p53, and myc, that regulate apoptosis are also expressed abnormally. Potent inducers of apoptosis including steroids, azathioprine, cyclophosphamide, and methotrexate are the most efficacious therapies for autoimmune disease currently known. Specific therapies that induce apoptosis without incurring side effects should improve treatment of autoimmune disease. Publication Types: Review Review, Tutorial PMID: 7524507 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 961: Science. 1994 Sep 30;265(5181):2091-3. Mediation of c-Myc-induced apoptosis by p53. Hermeking H, Eick D. Institut fur Klinische Molekularbiologie und Tumorgenetik Forschungszentrum fur Umwelt und Gesundheit, GSF, Munchen, Germany. The cellular proto-oncogene c-myc is involved in cell proliferation and transformation but is also implicated in the induction of programmed cell death (apoptosis). The same characteristics have been described for the tumor suppressor gene p53, the most commonly mutated gene in human cancer. In quiescent mouse fibroblasts expressing wild-type p53 protein, activation of c-Myc was found to induce apoptosis and cell cycle reentry, preceded by stabilization of p53. In contrast, in quiescent p53-null fibroblasts, activation of c-Myc induced cell cycle reentry but not apoptosis. These results suggest that p53 mediates apoptosis as a safeguard mechanism to prevent cell proliferation induced by oncogene activation. PMID: 8091232 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 962: Proc Natl Acad Sci U S A. 1994 Sep 13;91(19):9141-5. Protein farnesyltransferase inhibitors block the growth of ras-dependent tumors in nude mice. Kohl NE, Wilson FR, Mosser SD, Giuliani E, deSolms SJ, Conner MW, Anthony NJ, Holtz WJ, Gomez RP, Lee TJ, et al. Department of Cancer Research, Merck Research Laboratories, West Point, PA 19486. The posttranslational addition of a farnesyl moiety to the Ras oncoprotein is essential for its transforming activity. Cell-active inhibitors of the enzyme that catalyzes this reaction, protein farnesyltransferase, have been shown to selectively block ras-dependent transformation of cells in culture. Here we describe the protein farnesyltransferase inhibitor 2(S)-[2(S)-[2(R)-amino-3-mercapto]propylamino-3(S)-methyl] pentyloxy-3-phenylpropionylmethioninesulfone methyl ester (L-739,749), which suppressed the anchorage-independent growth of Rat1 cells transformed with viral H-ras and the human pancreatic adenocarcinoma cell line PSN-1, which harbors altered K-ras, myc, and p53 genes. This compound also suppressed the growth of tumors arising from ras-transformed Rat1 cells in nude mice by 66%. Under the same conditions, doxorubicin inhibited tumor growth by 33%. Control tumors formed by v-raf- or v-mos-transformed Rat1 cells were unaffected by L-739,749. Furthermore, mice treated with L-739,749 exhibited no evidence of systemic toxicity. This is a demonstration of antitumor activity in vivo using a synthetic small molecule inhibitor of protein farnesyltransferase. PMID: 8090782 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 963: J Natl Cancer Inst. 1994 Sep 7;86(17):1331-5. Comment in: J Natl Cancer Inst. 1994 Sep 7;86(17):1265-6. Oncogene amplification in urothelial cancers with p53 gene mutation or MDM2 amplification. Habuchi T, Kinoshita H, Yamada H, Kakehi Y, Ogawa O, Wu WJ, Takahashi R, Sugiyama T, Yoshida O. Department of Urology, Faculty of Medicine, Kyoto University, Japan. BACKGROUND: Previously, p53 (also known as TP53) gene mutations have been shown to be frequently detected in highly malignant urothelial cancers. Evidence has been accumulating that the disruption of the normal function of p53 may lead to genomic instability, including predisposition to gene amplification. Furthermore, the normal function of p53 may be abrogated by MDM2 (murine double minute-2) gene amplification in some human tumors. PURPOSE: Our purpose was to investigate the relationship between protooncogene amplification and p53 alteration in urothelial cancers by examining the existence of amplification of MDM2 and 14 other protooncogenes in 50 urothelial tumors in which p53 gene status was known. METHODS: We analyzed gene amplification by Southern-blot analysis in 50 urothelial cancer specimens. These tumors were previously examined for p53 mutations by polymerase chain reaction-single-strand conformation analysis, and 17 tumors contained p53 mutations. RESULTS: Two high-grade advanced tumors (4%) without p53 mutation harbored MDM2 amplification with concurrent int-2 gene amplification. As for other genes, amplification was detected for int-2 (also known as WNT2) (seven [14%] of 50), erbB-2 (also known as ERBB2) (three [6%] of 50), N-ras (also known as NRAS) (one [2%] of 50), L-myc (also known as MYCL1) (one [2%] of 50), and raf-1 (also known as RAF1) (one [2%] of 50). The amplification of at least one gene examined was observed in 11 (22%) of 50 tumors. The presence of p53 mutations was not significantly associated with the occurrence of gene amplification, since the amplification was detected in six (35%) of 17 tumors with p53 mutations and in five (15%) of 33 tumors without p53 mutations. However, eight (73%) of 11 tumors with proto-oncogene amplification harbored p53 mutations or MDM2 amplification. CONCLUSIONS AND IMPLICATIONS: A subset of advanced urothelial cancers without p53 mutations may harbor MDM2 amplification. This finding should be taken into account when adopting p53 alteration as a marker of aggressiveness in urothelial cancers. Although the abrogation of normal p53 function may be one of the key steps to protooncogene amplification, the data further indicate that the predisposition to gene amplification in urothelial cancers was not determined by the presence of p53 alteration alone. PMID: 8064891 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 964: J Neurosurg. 1994 Sep;81(3):427-36. Pathways leading to glioblastoma multiforme: a molecular analysis of genetic alterations in 65 astrocytic tumors. Lang FF, Miller DC, Koslow M, Newcomb EW. Department of Neurosurgery, New York University Medical Center, New York. To characterize some of the genetic events underlying the development of glioblastoma multiforme, the authors analyzed 65 astrocytic tumors (seven pilocytic astrocytomas, eight astrocytomas, 16 anaplastic astrocytomas, and 34 glioblastomas multiforme) for loss of heterozygosity for chromosome 17p, loss of heterozygosity for chromosomes 10p and 10q, amplification of the epidermal growth factor receptor (EGFR) gene, and amplification of the oncogenes N-myc, c-myc, and N-ras using Southern blot analysis. Alterations of the p53 gene (positive immunostaining for p53 protein in tumors with or without p53 gene mutations) in these 65 tumors were analyzed previously. None of the 65 tumors showed amplification or rearrangement of N-myc, c-myc, or N-ras oncogenes. The molecular analysis presented here demonstrates distinct variants of astrocytic tumors, with at least three genetic pathways leading to glioblastoma multiforme. One pathway was characterized by 43 astrocytomas with alterations in p53. Glioblastomas with p53 alterations may represent tumors that progress from lower-grade astrocytomas. This variant was more likely to show loss of chromosome 17p than tumors without p53 alterations (p < 0.04). Seventy-five percent of tumors with loss of one 17p allele demonstrated mutations in the p53 gene. Loss of chromosome 10 was associated with progression from anaplastic astrocytoma (13%) to glioblastoma (38%) (p < 0.04). Amplification of the EGFR gene was a rare (7%) but late event in tumor progression (p < 0.03). A second pathway was characterized by six astrocytomas without p53 alterations and may represent clinically de novo high-grade tumors. These tumors were more likely to show amplification of the EGFR gene (83%) than tumors with p53 alterations. Sixty percent of tumors with EGFR amplification also showed loss of chromosome 10; loss of chromosome 17p was infrequent in this variant. One or more alternative pathways were characterized by 16 astrocytomas without p53 alterations and with none of the genetic changes analyzed in this study. Glioblastomas are a heterogeneous group of tumors that may arise via multiple genetic pathways. PMID: 8057151 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 965: Carcinogenesis. 1994 Sep;15(9):1993-2002. Oncogene expression in hepatic and biliary neoplasms of the fish Rivulus ocellatus marmoratus: correlation with histologic changes. Goodwin AE, Grizzle JM. Department of Fisheries and Allied Aquacultures, Auburn University, AL 36849. One day old mangrove rivulus (Rivulus ocellatus marmoratus) were exposed to 9 mg/l diethylnitrosamine (DEN) for 6 weeks, kept in water without DEN for an additional 18-20 months, then necropsied. Oncogene expression was detected by immunohistochemical staining of freeze-dried cryofixed livers. Positive controls for immunohistochemistry included tumors grown by injecting athymic nude mice with cell lines having known oncogene expression. Livers from 15 DEN-exposed fish contained 178 altered foci and neoplasms; 48% of these lesions over-expressed Ras, Myc, Fos, p53 or epidermal growth factor receptor (EGFR). Raf overexpression was not detected. Myc overexpression was positively correlated (P < 0.05) with smaller hepatocyte size in both hepatocellular neoplasms and in altered foci. Increased EGFR expression occurred primarily in inflamed lesions. Increased Ras expression in hepatocellular neoplasms was correlated with anaplasia, gamma-glutamyltranspeptidase activity and lesions that contained mixed acinar and trabecular profiles. Accumulation of p53 occurred more often in neoplasms than in altered foci and correlated with unusual cytoplasmic vacuoles. In hepatocellular neoplasms, Fos overexpression was correlated with increased cell diameter, nuclear pleomorphism, and enlarged nucleoli. Only 1/14 biliary neoplasms overexpressed an oncoprotein (Myc). None of the changes in oncoprotein expression were correlated with cell proliferation (bromodeoxyuridine staining). Although several of the correlations found in mangrove rivulus also occur in mammals, the general relevance of some of our findings can be determined only after they are confirmed in other species. PMID: 7923595 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 966: Carcinogenesis. 1994 Sep;15(9):1985-92. Oncogene expression in hepatocytes of the fish Rivulus ocellatus marmoratus during the necrotic and regenerative phases of diethylnitrosamine toxicity. Goodwin AE, Grizzle JM. Department of Fisheries and Allied Aquacultures, Auburn University, AL 36849. Livers of mangrove rivulus (Rivulus ocellatus marmoratus) were examined after an acutely necrogenic dose of diethyl-nitrosamine (DEN). Immunohistochemical detection of oncoproteins and bromodeoxyuridine (BrdU), enzyme histochemical detection of gamma-glutamyltranspeptidase, and histological stains were used in an attempt to separate changes in protooncogene expression related to hepatic regeneration from those changes that were putatively preneoplastic. Perivenous hepatocytes were rounded and shrunken within 3 days of the beginning of DEN exposure, and widespread necrosis and hepatocyte proliferation occurred by 21 days (the last day of DEN exposure). Twenty-four days after the end of DEN exposure, livers were primarily composed of nodules of regenerated hepatocytes. Epidermal growth factor receptor expression in hepatocytes increased in inflamed areas and then returned to control levels as inflammation subsided. Increased expression of Fos, Ras and Myc occurred prior to necrosis in a zonal and chronological progression consistent with regeneration of hepatocytes. Fos, Ras, Myc and p53 expression persisted in scattered cells and foci for 24 days after the end of DEN exposure, and this expression was at levels higher than during normal cell-cycle progression. The spatial pattern and persistence of cells expressing Fos, Ras, Myc and p53 at high levels may have represented preneoplastic changes. PMID: 7923594 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 967: Pathol Res Pract. 1994 Sep;190(8):767-74. Mycosis fungoides: expression of C-myc p62 p53, bcl-2 and PCNA proteins and absence of association with Epstein-Barr virus. Kanavaros P, Ioannidou D, Tzardi M, Datseris G, Katsantonis J, Delidis G, Tosca A. Department of Pathology, University of Crete, Greece. The expression of C-myc p62, bcl-2, p53, PCNA and EBV-encoded LMP-1 proteins was studied by immunohistochemistry on paraffin-embedded skin specimens from 14 patients with early stage (premycotic erythema and second stage plaques) mycosis fungoides (MF), 21 patients with advanced stage MF (third stage plaques and tumors), 3 patients with Sezary's syndrome (SS) and 3 patients with pleomorphic medium and large cell cutaneous T-cell lymphomas (PML-CTCL). All 41 cases were also screened for the presence of EBV by using RNA in situ hybridization with EBER 1/2 oligonucleotides. Increased expression of C-myc p62, p53 and PCNA proteins was found in PML-CTCL and advanced stages of MF as compared to early stages of MF. These results suggest a relationship between levels of C-myc p62, p53 and PCNA proteins and aggressiveness of the cutaneous T-cell lymphomas. Furthermore, C-myc p62 and bcl-2 proteins were found to be frequently coexpressed in the present series. In view of the background information from in vitro findings and animal models that cooperation of C-myc and bcl-2 is important for lymphomagenesis, our results suggest that coexpression of these oncogenes may be implicated in the pathogenesis and/or the progression of cutaneous T-cell lymphomas. Neither LMP-1 expression nor EBV EBER l/2 transcripts were detected in our series suggesting that EBV is not involved in the pathogenesis of cutaneous T-cell lymphomas. PMID: 7831152 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 968: Cancer Genet Cytogenet. 1994 Aug;76(1):47-9. No association between c-myc amplification and TP53 mutation in sarcoma tumorigenesis. Castresana JS, Barrios C, Gomez L, Kreicbergs A. Department of Tumor Pathology, Karolinska Hospital, Stockholm, Sweden. Oncogenes and tumor suppressor genes coparticipate in sarcoma tumorigenesis. We tested 43 sarcomas for c-myc amplification by Southern blot and molecular hybridization techniques and TP53 mutations by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique and direct sequencing of the PCR products. We found eight tumors with c-myc amplification and five different tumors with TP53 mutations but no tumors harbor both c-myc and TP53 alterations. We suggest that c-myc amplification and TP53 mutations do not seem to coparticipate in the tumorigenesis of sarcomas. PMID: 8076351 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 969: Biochem Soc Trans. 1994 Aug;22(3):606-10. The regulation of apoptosis in thymocytes. McConkey DJ, Jondal M, Orrenius S. Department of Cell Biology, University of Texas, MD Anderson Cancer Center, Houston 77030. Publication Types: Review Review, Tutorial PMID: 7821647 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 970: Blood. 1994 Jul 15;84(2):397-402. Rearrangements of the BCL-6 gene in acquired immunodeficiency syndrome-associated non-Hodgkin's lymphoma: association with diffuse large-cell subtype. Gaidano G, Lo Coco F, Ye BH, Shibata D, Levine AM, Knowles DM, Dalla-Favera R. Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY 10032. Acquired immunodeficiency syndrome (AIDS)-associated non-Hodgkin's lymphomas (AIDS-NHL), a major source of morbidity and mortality among AIDS patients, are derived from B cells and can be classified into two main histologic categories, small noncleaved cell lymphoma (SNCCL) and diffuse large-cell lymphoma (DLCL). DLCL includes two histologic subsets, ie, large noncleaved cell lymphoma (LNCCL) and large cell-immunoblastic plasmacytoid lymphoma (LC-IBPL). Several studies have shown that AIDS-SNCCL is associated with the clonal accumulation of multiple genetic lesions, including Epstein-Barr virus (EBV) infection, activation of the c-MYC and RAS oncogenes, as well as inactivation of the p53 tumor suppressor gene at variable frequencies. On the contrary, the molecular pathogenesis of AIDS-DLCL is largely obscure, because no genetic lesion other than EBV infection has been specifically identified in this group. In this study, we have tested a panel of 40 AIDS-NHL for structural alterations of BCL-6, a putative proto-oncogene that is frequently altered in DLCL in the immunocompetent host. Our results show that rearrangements of BCL-6 are present in 20% of AIDS-DLCL (5 of 24), including 2 of 8 LNCCL and 3 of 16 LC-IBPL, but in no case of AIDS-SNCCL. BCL-6 rearrangements were detected both in the presence and in the absence of EBV infection of the tumor clone, but in no case were associated with activation of c-MYC or mutations of p53. These data identify a novel genetic lesion in AIDS-DLCL and corroborate the notion that lymphomagenesis in AIDS follows two distinct molecular pathways that are associated with the development of histologically distinct types of AIDS-NHL. PMID: 8025268 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 971: Oncogene. 1994 Jul;9(7):2009-17. Differential sensitivity of normal and Ha-ras-transformed C3H mouse embryo fibroblasts to tumor necrosis factor: induction of bcl-2, c-myc, and manganese superoxide dismutase in resistant cells. Fernandez A, Marin MC, McDonnell T, Ananthaswamy HN. Department of Immunology, University of Texas M.D. Anderson Cancer Center, Houston. In this study, we investigated the role of activated Ha-ras oncogene on the growth-regulatory properties of tumor necrosis factor (TNF) in C3H mouse embryo fibroblasts. TNF-resistant 10T1/2 cells transfected with an activated Ha-ras oncogene not only produced tumors in nude mice but also exhibited extreme sensitivity to cytolysis by TNF. TNF-induced cell death was mediated through apoptosis. The differential sensitivity of normal and Ha-ras transformed cells to TNF was not due to differences in the number of TNF receptors on their cell surface. However, TNF-resistant cells, but not sensitive cells, overexpressed bcl-2, c-myc, and manganese superoxide dismutase (MnSOD) mRNA following exposure to TNF. In addition, TNF treatment resulted in a marginal induction of p53 mRNA in both TNF-sensitive and resistant cells. These results suggest that TNF-induced cytotoxicity involves apoptosis and that TNF-induced over-expression of bcl-2, c-myc, and MnSOD genes is associated with TNF resistance in C3H mouse embryo fibroblasts. PMID: 8208546 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 972: Blood. 1994 Jul 1;84(1):270-8. Frequent p53 gene involvement in splenic B-cell leukemia/lymphomas of possible marginal zone origin. Baldini L, Fracchiolla NS, Cro LM, Trecca D, Romitti L, Polli E, Maiolo AT, Neri A. Servizio di Ematologia, Istituto di Scienze Mediche, Universita di Milano, Ospedale Maggiore, IRCCS, Italy. A phenotypic and molecular evaluation was made of 15 patients with mature B-cell leukemia/lymphoma showing exclusive spleen and bone marrow involvement. According to French-American-British criteria, these cases could not be classified as classical B-cell chronic lymphocytic leukemia, hairy cell leukemia and its variant forms, splenic lymphoma with villous lymphocytes, or leukemic phase non-Hodgkin's lymphoma (NHL; follicular or intermediate type). The immunophenotype pattern (high surface Ig and CD25 expression, and little or no reactivity with CD5, CD23, and CD11c) and cytomorphologic features of these neoplasms suggested an origin in the marginal zone of the spleen. Molecular analysis did not show any involvement of the dominantly acting oncogenes generally associated with lymphoid malignancies (c-myc, bcl-2, bcl-1, Ras), but mutations of the p53 tumor suppressor gene involving exons 5, 6, and 8 were found in 6 cases (6 of 15, 40%). In 4 cases, the p53 alterations consisted of a point mutation leading to amino acid substitution. In the remaining 2 cases, an insertion or deletion resulting in a frame-shift of the protein was observed. In all but 1 of the cases, the wild-type sequence at the mutation site was barely visible, implying the loss of the normal p53 allele in leukemic cells. All of the cases showed a clinical course compatible with that of low-grade NHL, regardless of the p53 loss/mutation. Overall, our data suggest the existence of a form of splenic B-cell leukemia/lymphoma of possible marginal zone origin in which p53 inactivation may play an important pathogenetic role. PMID: 8018922 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 973: Int J Cancer. 1994 Jul 1;58(1):24-32. p53 genetic abnormalities and myc activation in human lung carcinoma. Gazzeri S, Brambilla E, Caron de Fromentel C, Gouyer V, Moro D, Perron P, Berger F, Brambilla C. Service de Pneumologie, Universite Joseph Fourier, Centre Hospitalier Albert Michallon, Grenoble, France. p53 mutations and myc gene amplification and expression were studied in 119 lung carcinomas of all histological types. A mutant p53 immunophenotype was previously found in 47% of these tumors by immunohistochemical analysis. Seven cases exhibited p53 genomic rearrangements on Southern blots. Elevated levels of p53 transcript were found in 12 carcinomas (10%) and decreased levels in 27 carcinomas (23%) on Northern blots. In most of the cases, low levels of transcript were associated with negative immunostaining, whereas elevated levels of mRNA were related to positive immunostaining (mutant immunophenotype). p53 RT/PCR analysis in 10 tumors with absence of transcript on Northern blots revealed only weak or absent expression of normal and/or altered size transcripts. These abnormal transcripts showed deletions, insertions or splicing abnormalities. Taken together, p53 abnormalities were found in 66% of lung carcinomas [52% of neuroendocrine (NE) carcinomas and 75% of NSCLC]. c-myc was found to be activated in 24% (10/42) of these NE and in 48% (33/69) of these NSCLC carcinomas using Southern- and Northern-blot techniques. In addition, L- and N-myc genes were also activated in 26% (10/42) of NE carcinomas. No correlation was found between p53 mutations and myc activation in SCLC or in NSCLC, but their association was significantly more frequent in NSCLC than in SCLC. These results indicate that the p53-positive immunophenotype uncovers the occurrence of p53 point mutations in lung cancer and that p53 and c-myc gene alterations are important but represent independent occurrences in the development of lung tumors. PMID: 8014012 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 974: Mol Biol Cell. 1994 Jul;5(7):763-72. Loss of cell cycle controls in apoptotic lymphoblasts of the bursa of Fabricius. Neiman PE, Blish C, Heydt C, Loring G, Thomas SJ. Fred Hutchinson Cancer Research Center, Seattle, Washington. Lymphoblasts of the normal embryonic follicles of the chicken bursa of Fabricius undergo rapid apoptosis when exposed to gamma-radiation or when cell-cell contacts are disrupted by mechanical dispersion in short term culture. We have observed previously that overexpression of v-myc sensitizes preneoplastic bursal lymphoblasts to induction of cell death, whereas resistance to induced cell death is acquired during progression to neoplasia. In this study we observed extensive DNA degradation in the large majority of the lymphoblast population within the first hour after dispersion-induced apoptosis. Paradoxically these cells continued to progress into S-phase with the bulk of DNA cleavage and death occurring in S-phase cells (i.e., in cells with more than 2C and less than 4C DNA content). We confirmed the S phase status of apoptotic cells by determining that detection of nuclear cyclin A in individual cells also corresponded with detection of DNA breakage. Levels of cyclin E, cyclin E-dependent H1 histone kinase, and p53 proteins were maintained during dispersion-induced DNA cleavage. gamma-radiation failed either to inhibit cell cycle progression or to raise p53 levels in dispersed bursal lymphoblasts. In intact bursal follicles low doses of gamma-radiation induced p53 whereas higher, apoptosis-inducing doses failed to induce p53 or prevent G1 to S-phase progression. These results suggest that normal DNA damage-induced cell cycle checkpoint controls are lost or overridden when apoptosis is induced in bursal lymphoblasts. PMID: 7812045 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 975: Proc Natl Acad Sci U S A. 1994 Jun 21;91(13):5878-82. c-myc and bcl-2 modulate p53 function by altering p53 subcellular trafficking during the cell cycle. Ryan JJ, Prochownik E, Gottlieb CA, Apel IJ, Merino R, Nunez G, Clarke MF. Department of Medicine, University of Michigan Medical Center, Ann Arbor 48109. We have studied the ability of c-myc and bcl-2 oncogenes to modulate p53 function. Our studies show that coincident expression of human Bcl-2 protein with p53 prolongs survival of murine erythroleukemia cells. This effect was associated with a loss of the G1 specificity of p53-mediated cell cycle arrest. Furthermore, we found that the c-myc and bcl-2 genes cooperate to inhibit p53 functions. Coexpression of bcl-2 and c-myc can totally overcome p53-induced apoptosis and cell cycle arrest by altering the subcellular trafficking of p53 during the cell cycle: the p53 remains in the cytoplasm of the cotransfected cells during a critical period in G1. This finding suggests a mechanism by which normal hematopoietic progenitors can survive and proliferate despite p53 expression and by which the inappropriate expression of bcl-2 and c-myc can cooperate in transformation. PMID: 8016082 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 976: Blood. 1994 Jun 15;83(12):3581-90. Molecular characterization of CD30+ anaplastic large-cell lymphoma: high frequency of c-myc proto-oncogene activation. Inghirami G, Macri L, Cesarman E, Chadburn A, Zhong J, Knowles DM. Division of Surgical Pathology, College of Physicians and Surgeons of Columbia University, New York, NY. Anaplastic large-cell lymphoma (ALCL) represents a morphologically distinct type of non-Hodgkin's lymphoma (NHL) characterized phenotypically by the expression of the CD30 antigen, a new member of the nerve growth factor gene family. The lymphoid origin of ALCL has been documented using immunohistochemical and molecular genetic analyses. However, very little is known so far regarding the precise pathogenetic mechanisms involved in its development and progression. Therefore, we investigated bcl-2, p53, and retinoblastoma gene (Rb) expression immunohistochemically; the occurrence of bcl-2, c-myc, and Rb gene rearrangements using Southern blotting; and the presence of ras and p53 gene somatic mutations by single-strand conformation polymorphism assay in a panel of 18 well-characterized ALCLs. In addition, the presence of Epstein-Barr (EBV) and human T-cell lymphotropic virus type I (HTLV-I) genomes were investigated using polymerase chain reaction. We identified abnormal c-myc gene products in 6 of 18 cases (33%) of ALCL. On the other hand, the bcl-2 and Rb genes were not rearranged and K-, N-, and H-ras gene somatic mutations were not found. Significant levels of p53 protein expression were found in more than 60% of ALCLs, but only a single ALCL carried a p53 gene mutation (exon 5). Only 3 ALCL cases, all occurring in human immunodeficiency virus-infected patients, were positive for EBV genomes. On the other hand, contrary to previous findings, no HTLV-I products could be identified. Despite the fact that the c-myc proto-oncogene appears to be frequently altered in ALCL, no pathognomonic abnormality could be identified and therefore additional studies and new strategies should be designed to identify the pathogenetic mechanisms involved in the development of ALCL. PMID: 8204884 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 977: Cancer. 1994 Jun 15;73(12):3087-93. Low frequency of the p53 gene mutations in neuroblastoma. Hosoi G, Hara J, Okamura T, Osugi Y, Ishihara S, Fukuzawa M, Okada A, Okada S, Tawa A. Department of Pediatrics, Osaka University Hospital, Japan. BACKGROUND. The p53 gene frequently is affected by point mutations, rearrangements, or deletions that contribute to the genesis or progression of a wide variety of human adult solid tumors; however, to the authors' knowledge, this gene alteration has not been analyzed in neuroblastoma. METHODS. Genomic DNA samples from 20 children with neuroblastoma, including 16 patients with advanced disease, were screened for the presence of mutations in exons 5-9 of the p53 gene, where over 90% of mutations have been reported to be located in human cancer. The screening technique employed polymerase chain reaction/single-strand conformation polymorphism analysis followed by direct DNA sequencing. RESULTS. Heterozygous mutations were detected in 2 of the 20 cases. A silent mutation (T to G transversion) at codon 172 and a missense mutation (G to T transversion) at codon 259 were found in patients with Stage II and Stage IV disease, respectively. Thus, p53 mutations were found to occur in neuroblastoma, but at a low frequency (2 of 20). CONCLUSIONS. Our data suggest that in a minority of neuroblastomas, p53 gene mutations may play a contributing role in tumorigenesis, but other genes presumably play a major role in this tumor. PMID: 8200007 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 978: Trends Microbiol. 1994 Jun;2(6):185-7. Viruses and cancer. Chalcraft T. PMID: 8087449 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 979: Lab Invest. 1994 Jun;70(6):875-88. Modulation of oncogene and tumor suppressor gene expression in a hamster model of chronic lung injury with varying degrees of pulmonary neuroendocrine cell hyperplasia. Sunday ME, Willett CG, Patidar K, Graham SA. Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts. BACKGROUND: Intense pulmonary neuroendocrine cell (PNEC) hyperplasia occurs during preneoplastic lung injury in hamsters treated with diethylnitrosamine (DEN) plus hyperoxia. Alterations in oncogene and tumor suppressor gene expression during this process have not been explored. EXPERIMENTAL DESIGN: Our goals were: (a) to analyze expression of genes potentially involved in growth and differentiation of PNECs and/or nonneuroendocrine pulmonary epithelial cells (non-PNECs) in hamsters treated for up to 20 weeks with hyperoxia and DEN or the major tobacco-derived nitrosamine, 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK); and (b) as a corollary, to determine which cells were most mitotically active by immunostaining for c-myc and proliferating cell nuclear antigen. RESULTS: Immunohistochemical analyses demonstrated intense PNEC hyperplasia after treatment with either DEN/O2 or NNK/O2. Whereas DEN/O2-induced PNEC hyperplasia spontaneously regressed, NNK/O2-induced PNEC hyperplasia continued to increase up to 20 weeks. Rb transcripts were decreased similarly in lungs from all treatment groups (NNK/O2 = DEN/O2 = DEN alone) in spite of large differences in PNEC hyperplasia between these groups. c-myc was overexpressed in lungs from animals treated with NNK/O2, DEN/O2 and DEN alone, in which c-myc protein immunostaining occurred predominantly in non-PNECs. Proliferating cell nuclear antigen immunostaining confirmed that non-PNECs were most mitotically active. CONCLUSIONS: These data indicate that PNEC hyperplasia is primarily due to PNEC differentiation, suggesting that this model is ideal for studying mechanisms of neuroendocrine differentiation. Paracrine effects of PNEC-derived growth factors may then contribute to dysregulation of non-PNEC growth preceding the ultimate development of non-neuroendocrine lung tumors in nitrosamine-treated hamsters. PMID: 8015292 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 980: Placenta. 1994 Jun;15(4):399-409. C-myc and tumour suppressor gene product expression in developing and term human trophoblast. Roncalli M, Bulfamante G, Viale G, Springall DR, Alfano R, Comi A, Maggioni M, Polak JM, Coggi G. II Department of Pathology, University of Milan, School of Medicine, Italy. Proliferation and differentiation of villous trophoblast during placental development, from an early stage to full-term, were investigated in routinely fixed and processed tissues, by means of the immunocytochemical localization of the cell cycle-related proto-oncogene c-myc and the p53 and retinoblastoma susceptibility (Rb) tumour-suppressor gene products. The proliferative activity of the trophoblast was determined using an antibody against proliferating cell nuclear antigen (PCNA) which stains all proliferating cells in paraffin-embedded tissues. Diffuse nuclear immunoreactivity for PCNA, c-myc and Rb gene products was a consistent finding in early cytotrophoblast; c-myc product expression was also detectable in both layers of mid-gestation trophoblast. Only scattered cytotrophoblastic nuclei of early gestational placenta displayed immunostaining for p53 gene product. In full-term placenta c-myc expression was undetectable while Rb gene product and PCNA immunoreactivity declined markedly. These results indicate that the expression of the above genes is spatio-temporally regulated during placental development. A potential involvement of the oncosuppressor gene products p53 and Rb in the control of trophoblastic proliferation and of c-myc in the control of both the proliferative and differentiation pathways of trophoblastic cells is suggested. PMID: 7937596 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 981: Int J Radiat Biol. 1994 Jun;65(6):665-73. Alterations in oncogene expression and radiosensitivity in the most frequently used SV40-transformed human skin fibroblasts. Lucke-Huhle C. Kernforschungszentrum Karlsruhe, Institut fur Genetik, Germany. In comparison with primary cell cultures, SV40-transformed human skin fibroblasts, either from healthy donors or from patients suffering from ataxia-telangiectasia (AT) or xeroderma pigmentosum, are more resistant to the cytotoxic action of low LET 60cobalt gamma-rays as well as to high LET alpha-particles. Resistance factors calculated from D10's lie between 1.4 and 2.0. Northern blot analysis reveals spontaneous overexpression of the oncogenes c-myc, Ki-ras and c-raf and of the tumour suppressor gene p53 as a consequence of SV40 transformation. For c-myc, the increased expression is due to gene amplification and gene rearrangement. An even further increase in the expression of c-myc has been found for AT cells (AT5BI-VA) after moderate doses of 60cobalt gamma-irradiation. A possible correlation between SV40-induced changes in gene expression and cellular radioresistance is discussed. PMID: 7912716 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 982: Acad Med. 1994 Jun;69(6):441-4. You can't get there from here: the tortuous road to basic research. Weinberg RA. Whitehead Institute for Biomedical Research, Cambridge, MA 02142-1479. Basic researchers are on the defensive as pressures increase for them to translate their findings into palpable amelioration of the human condition. Yet recognition of the need and importance of practical applications hardly leads to a quick consensus about solutions; indeed, some proposed solutions appear to threaten the practice of basic science, especially those that favor focusing less on curiosity-driven research and more on application-oriented "quick-fix" research. Whatever solutions are developed, they must not weaken the basic science approach, which is essential. To illustrate this opinion, the author discusses one field of biomedical research, the various attempts to treat human cancers, specifically breast cancer. Such attempts have been launched in the face of an almost total ignorance of why cancer cells grow uncontrollably. For that reason, the author and many others believe that the best hope for breakthroughs in cancer treatment lies in greater understanding of the molecular and genetic mechanisms responsible for cell growth. The record shows that the knowledge only recently gained about these mechanisms came unexpectedly from several areas of curiosity-driven research having no apparent connection with the problem of human cancer. No one could have planned those investigations in a way that could anticipate, let alone guarantee, the important insights into cancer that resulted. Also, because these cell-growth mechanisms are used for other biological processes in the body, research on cancer cells often has yielded understanding about other non-malignant diseases (e.g., aspects of autoimmune disease, diabetes, hypertension, and nerve-cell dysfunction).(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 7911671 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 983: Semin Oncol. 1994 Jun;21(3):320-9. Molecular biology of head and neck cancer. Brachman DG. West Michigan Cancer Center, Kalamazoo, MI 49007. Publication Types: Review Review, Tutorial PMID: 7911603 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 984: Biochem Biophys Res Commun. 1994 May 30;201(1):266-83. Selective induction of apoptosis in myeloid leukemic cell lines by monoacetone glucose-3 butyrate. Calabresse C, Venturini L, Ronco G, Villa P, Degos L, Belpomme D, Chomienne C. Laboratoire Universite Paris 7 (Biologie Cellulaire Hematopoietique), Centre Hayem, Hopital Saint-Louis, France. Butyric acid is a potent cell growth inhibitor and differentiation inducer. Our previous studies have shown that MAG=3but, a monosaccharide ester of butyric acid, used at 1 mM, induces apoptosis in the HL-60 cell line. We report here that this drug can also induce apoptosis in the U-937 leukemic cell lines whereas the myeloblastic KG1 and the NB4 promyelocytic leukemic cell lines were refractory to induction of apoptosis. In order to determine what can trigger cells to undergo apoptosis, cell cycle analysis, induction of differentiation and p53, c-myc and Bcl-2 expression was studied. Apoptosis was correlated to an arrest of cell growth in the G1 phase of the cell cycle and to an induction of differentiation through the monocytic pathway in HL-60 and U-937 cells. Time course studies demonstrated DNA fragmentation after few hours incubation with the drug, while morphological signs appeared later (days 2 or 3). Northern blot analysis and flow cytometric studies have shown that cell death induced by MAG=3but was not associated to an overexpression of c-myc and p53. However, in the HL-60 cells, BCL-2 protein expression was decreased after MAG=3but treatment, corroborating the apoptosis observed. PMID: 8198584 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 985: Gan To Kagaku Ryoho. 1994 May;21 Suppl 1:108-16. [DNA content analysis and detection of c-myc and p53 products using flow cytometry in resected lung cancer cases] [Article in Japanese] Chiba W, Sawai S, Ikeda S, Morimoto K, Wazawa H, Hanawa T, Yamashita N, Matsui T, Hatakenaka R, Matsubara Y, et al. Respiratory Disease Center, Kyoto-Katsura Hospital. We quantitatively analyzed the c-myc and p53 products using flow cytometry in 28 cases of resected lung cancer and one case each of chorio-carcinoma, plasmacytoma, malignant mesothelioma and sclerosing hemangioma. In the lung cancer cases, c-myc and p53 products were detected in 10 cases (35%) and 7 cases (21%), respectively. These rates are higher than the DNA abnormal expression rates of the c-myc and p53 genes (15% and 12%, respectively) in our own data. In the adenocarcinoma of lung cancer cases, c-myc and p53 products were detected in 9 cases (53%) and 5 cases (29%), respectively. Among the squamous cell carcinoma cases, there were one case (11%) of c-myc expression and one case (11%) of p53 expression. DNA content analysis of the lung cancer patients revealed 7 cases of DNA diploidy and 21 cases of DNA aneuploidy. All 10 c-myc-positive cases showed DNA aneuploidy; thus the positive rate for c-myc products in the DNA aneuploidy cases was significantly different compared with the DNA diploidy cases (p < 0.05). In the sclerosing hemangioma case, we detected both c-myc and p53 products. Sclerosing hemangioma has been thought to be a benign tumor, but it may be a malignant tumor. PMID: 8203922 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 986: Mol Carcinog. 1994 May;10(1):8-14. A role for myn in Ha-ras transformation of mouse 10T1/2 fibroblasts. Taylor WR, Wright JA. Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Canada. The human max protein has been shown to form heterodimers with myc family proteins. The ability of myc+max heterodimers to act as sequence-specific transcriptional activators appears to be essential for the oncogenic activity of myc. max (also called myn in murine cells) can homodimerize to form a transcriptionally inactive complex. We previously showed that in mouse 10T1/2 cells, a combination of activated ras, c-myc, and a mutant form of p53 can cooperate in the induction of cellular transformation and metastasis. In the study presented here, we tested the hypothesis that expression of the myn gene may play a role in this cooperative process. Analysis of myn mRNA in these cell lines revealed the presence of a major 2.0-kb RNA species. This message and the 21- and 22-kDa myn polypeptides it encodes were significantly overexpressed in cells transformed by activated ras alone, by ras in combination with c-myc or mutant p53, or by ras plus myc plus mutant p53, in comparison with untransformed parental 10T1/2 cells. We also found that induction of ras expression in a cell line harboring an inducible ras gene was accompanied by an increase in myn mRNA expression. Interestingly, cotransfection of 10T1/2 cells with ras and myn inhibited cellular transformation in a focus-forming assay when compared with transfection with ras alone. These results suggest a role for ras in the regulation of myn gene expression and suggest a model of oncogene cooperativity in which the relative levels of myc and myn gene expression can influence ras transformation of mouse 10T1/2 cells. PMID: 8185831 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 987: Oncogene. 1994 May;9(5):1469-72. The mdm-2 oncogene is translocated and overexpressed in a murine plasmacytoma cell line expressing wild-type p53. Berberich S, Cole M. Department of Biochemistry and Molecular Biology, Wright State University, Dayton, Ohio. The cellular p53 protein has been demonstrated to possess growth-inhibitory activity. Recent work suggests that the murine double minute gene (mdm-2) encodes a protein that may function as a cellular regulator or mediator of p53 function. We were interested in determining if the mdm-2 gene was overexpressed in mouse tumor cells, in particular mouse plasmacytomas that harbor wild type-p53 protein. A novel chromosomal translocation of the mdm-2 gene was detected in the SP2 cell line, that is derived from plasmacytoma MOPC21. The translocation results in a head-to-head arrangement of the mdm-2 gene (chromosome 10) with the immunoglobulin C kappa gene (chromosome 6), analogous to the translocations that activate the c-myc gene in murine plasmacytomas. Based on Northern blot analysis, the translocation induces a 10-fold elevation of mdm-2 RNA. Primer extension assays demonstrate that the 5' end of the mdm-2 RNA from the translocated gene is colinear with the 5' mdm-2 mRNA from an unrearranged gene, suggesting that the mRNA and encoded protein are unaltered. This chromosomal translocation represents the first example in which mdm-2 overexpression is activated by a genetic alteration other than gene amplification. PMID: 8152809 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 988: Anticancer Res. 1994 May-Jun;14(3B):1357-60. Detection of the tumour suppressor gene p53 in nasopharyngeal carcinoma in Hong Kong Chinese. Porter MJ, Field JK, Lee JC, Leung SF, Lo D, Van Hasselt CA. Department of Surgery, Prince of Wales Hospital, Chinese University of Hong Kong. This study has investigated the expression of the p53 tumour suppressor gene in 41 cases of primary nasopharyngeal carcinomas (NPC) using the p53 monoclonal antibody BP53-12. Moderate p53 expression was found in 54% and strong expression in 12% of the specimens. There was no correlation between p53 expression and any of the clinicopathological parameters or survival. Surprisingly, three research groups have investigated p53 mutations in NPC and found no fresh tumour specimens to contain p53 mutations in exons 4-8 of the gene. It may be argued that as p53 overexpression has been demonstrated in 70% of the patients investigated in this study, that the mutations lie outside the 4-9 exon region. We are in the process of testing this hypothesis. PMID: 8067705 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 989: Rinsho Byori. 1994 Apr;42(4):355-8. [Molecular diagnosis of lung carcinoma] [Article in Japanese] Noguchi M. Pathology Division, National Cancer Center, Tokyo. For lung cancer diagnosis, the diagnostic significance of the ras, myc, erbB2 oncogenes, and the p53 anti-oncogene was reviewed. Point mutation of the ras oncogene, amplification of the myc oncogene, and overexpression of the erbB2 oncogene are associated with poor prognosis of lung carcinomas. Mutation of p53 anti-oncogene is a common event of lung carcinoma and the differences in its mutation pattern can be used for the molecular diagnosis of multicentric lung carcinomas. Publication Types: Review Review, Tutorial PMID: 8176843 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 990: Mayo Clin Proc. 1994 Apr;69(4):359-65. Aggressive medulloblastoma with high-level N-myc amplification. Tomlinson FH, Jenkins RB, Scheithauer BW, Keelan PA, Ritland S, Parisi JE, Cunningham J, Olsen KD. Department of Neurologic Surgery, Mayo Clinic Rochester, Minnesota 55905. A 27-year-old man was treated for an aggressive cerebellar medulloblastoma that, at operation, exhibited dural invasion. Six months after gross total resection and radiation therapy, a "surgical metastasis" developed in the lower portion of the surgical scar. The tumor grew rapidly down into the right side of his neck. Chemotherapy failed, and he subsequently died. Cytogenetic and molecular genetic studies revealed multiple numeric and structural chromosome abnormalities, including an abnormal chromosome 17p arm, more than 100-fold N-myc amplification, a rearranged c-myc gene, and a 16-base pair deletion involving exon 7 of the p53 gene. We postulate that these genetic features may have contributed to the aggressive behavior of the tumor. Publication Types: Case Reports PMID: 8170180 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 991: Gan To Kagaku Ryoho. 1994 Apr;21(5):596-601. [Cytotoxic action of alkylating agents in human tumor cells and its relationship to apoptosis] [Article in Japanese] Ikenaga M. Radiation Biology Center, Kyoto University, Japan. Various anticancer agents have been known to induce apoptosis in certain types of human tumor cells. The fact that a variety of agents, which attack different cellular targets, induce common apoptotic cell death suggests that the nature of initial damage is not directly involved in apoptosis. The mechanism by which a damage leads to apoptosis is not known. However, modulation of this process may affect the outcome of anticancer drug treatment. This article briefly reviewed the studies of endogenous as well as exogenous factors which modulate apoptosis, and then described the characteristics of cell death induced by alkylating agents. O6-Alkylguanine, a major cytotoxic DNA damage produced by simple alkylating agents, can be repaired by the cellular enzyme O6-methylguanine-DNA methyltransferase (MGMT). About one-fifth of human tumor cell strains lack the MGMT activity and termed as Mer- cells. Mer- cells are hypersensitive to alkylating agents like chloroethyl nitrosoureas (CNUs), compared with repair-proficient Mer+ cells. It is suggested that identification of a factor which suppresses the MGMT gene expression in CNU-resistant Mer+ cells, may enable us to convert these Mer+ cells to Mer- phenotype, thus resulting in much higher sensitivity of Mer+ cells to CNUs. Publication Types: Review Review, Tutorial PMID: 8154884 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 992: Gan To Kagaku Ryoho. 1994 Apr;21(5):591-5. [Molecular biology of cell death] [Article in Japanese] Tsujimoto Y. Dept. of Medical Genetics, Osaka University Medical School, Suita, Japan. Apoptosis is an active mechanism for cell death that is characterized by unique biochemical processes, including nuclear condensation, cytoplasmic compaction and breaking up of the cells into a number of membrane-bound fragments called apoptotic bodies. Many physiological cell death is known to proceed by apoptosis, and importance of cell death in a variety of biological phenomena is now well recognized. Eukaryotic molecular biology resulted in the identification of several genes with an ability to modulate apoptosis. Some genes induce and the others inhibit apoptotic cell death. These include oncogenes (bcl-2, myc etc), anti-oncogenes (p53) and cell surface antigen genes (Fas, TNF receptor etc). Genetical approach to dissect programmed cell death, majority of which proceed by apoptosis resulted in the identification of several crucial genes involved in cell death processes (ced 3, ced 4, ced 9 etc. in C. elegans). In this chapter, I will overview genes involved in cell death, and show where we are now standing toward complete understanding of apoptosis in biochemical terms. Publication Types: Review Review, Tutorial PMID: 8154883 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 993: Carcinogenesis. 1994 Apr;15(4):695-700. Permissivity for methotrexate-induced DHFR gene amplification correlates with the metastatic potential of rat adenocarcinoma cells. Lucke-Huhle C. Kernforschungszentrum Karlsruhe, Institut fur Genetik, Germany. During selection for methotrexate (MTX) resistance the metastatic subclone BSp73ASML of a spontaneous rat adenocarcinoma and a metastatic transfectant containing the metastogene META-1 underwent amplification of the dihydrofolate reductase (DHFR) gene at accelerated rates in contrast to non-metastatic but closely related BSp73AS cells. A four log increase in MTX resistance was associated with a 16-fold amplification and increased expression of the DHFR gene. The capacity for gene amplification in metastatic BSp73ASML cells was correlated with a deletion in the p53 gene and enhanced expression of the oncogene c-myc due to a 10-fold amplification of the myc gene. Increased expression of Ki-ras and c-raf in the non-metastatic BSp73AS cells seems to confer tumorigenicity but not permissivity for gene amplification. PMID: 8149482 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 994: Radiat Res. 1994 Apr;138(1):93-8. Induction of stable p53 oncoprotein and of c-myc overexpression in cultured normal human uroepithelium by radiation and N-nitrosodiethanolamine. Mothersill C, Harney J, Seymour CB. Radiation Science Centre, Dublin Institute of Technology, Ireland. Uroepithelium cultured from normal patients without cancer (60 individuals) was found to segregate into four subtypes based on the level of carcinogen treatment needed to induce abnormal p53 and c-myc. Twenty-two percent of patient cultures never showed abnormal p53 expression, even after chronic exposure to nitrosamines, in addition to irradiation. In these cultures, c-myc expression was confined to viable, normal-appearing cells at the growing edge of the culture and to apoptotic bodies. Twenty-eight percent of cultures were negative for abnormal p53 unless challenged with both radiation and chronic administration of nitrosamines, while a further 26% required only a single dose of radiation to induce the abnormal protein. The remaining patients had tissue which, while initially negative for stable p53, became positive when put into culture and stimulated to grow. The c-myc protein was overexpressed in all cultures with abnormal p53. It would appear that elevated expression of conformationally inactive p53 and of high levels of c-myc represents an early response of normal uroepithelial cells to carcinogen challenge. It also appears that a relatively high number of patients without cancer express these proteins when their cells are challenged to grow; a pre-exposure to environmental carcinogens such as nitrosamines in cigarette smoke is likely to be involved. PMID: 8146306 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 995: J Biol Chem. 1994 Apr 1;269(13):9582-9. Degradation of the tumor suppressor protein p53 by the ubiquitin-mediated proteolytic system requires a novel species of ubiquitin-carrier protein, E2. Ciechanover A, Shkedy D, Oren M, Bercovich B. Department of Biochemistry, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa. The tumor suppressor protein p53 is extremely unstable in most cell lines. In contrast, many mutant and oncogenic species of the protein are stable. The degradation of p53 in vivo requires metabolic energy; however, the proteolytic system(s) involved have not been identified. The ubiquitin system has been implicated in the degradation of p53 in vitro. The degradation is stimulated significantly by the human papillomavirus (HPV) oncoprotein E6 that associates with p53 and facilitates conjugate formation and subsequent degradation. Complex formation between E6 and p53 is promoted by a cellular protein designated E6-associated protein (E6-AP). Initial dissection of the conjugation process have demonstrated a role for the ubiquitin-activating enzyme, E1, but the ubiquitin-carrier protein (E2, UBC) and the ubiquitin protein ligase, E3, have not been identified. In this study, we report that a novel species of ubiquitin-carrier protein designated E2-F1 (Blumenfeld, N., Gonen, H., Mayer, A., Smith, C., Siegel, N.R., Schwartz, A.L., and Ciechanover, A. (1994) J. Biol. Chem. 269, 9574-9581) is involved in the conjugation and degradation of p53. This E2 enzyme recognizes non-"N-end rule" protein substrates and appears to mediate their conjugation via a novel species of E3. The process of recognition appears to be selective; E2-F1 is not required for the conjugation and degradation of human N-myc. The involvement of E2-F1 in the in vitro process appears to be physiologically meaningful and to reproduce the in vivo process; mutant species of p53 that do not interact with E6 and are stable in vivo are not recognized by the cell free system. PMID: 8144545 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 996: Zhonghua Bing Li Xue Za Zhi. 1994 Apr;23(2):100-3. [c-myc gene and p53 protein expression in human primary liver carcinoma] [Article in Chinese] Cai DW, Gao CZ, Wang NJ. Department of Pathology, Nantong Medical College. Photobiotin-labelled c-myc gene probe was used to study primary liver carcinoma (PHC) by in situ hybridization on the paraffin sections as well as immunohistochemistry staining for p53 protein expression in 42 cases from high liver cancer incidence regions. The results are as follows: c-myc gene and p53 protein expression were both located in the nuclei. The positive incidences of overexpression of both c-myc gene and p53 protein in PHC were 76% and 55% respectively. The distribution and strength of the overexpression of c-myc gene and p53 protein in PHC are related to the degree of cell differentiation and the overexpression in the liver tissue surrounding the carcinoma is lower than that detected in the PHC tissue. PMID: 8082236 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 997: Carcinogenesis. 1994 Apr;15(4):583-7. Determination of the allelic frequencies of an L-myc and a p53 polymorphism in human lung cancer. Weston A, Ling-Cawley HM, Caporaso NE, Bowman ED, Hoover RN, Trump BF, Harris CC. Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892. The L-myc and p53 genes have been implicated in lung cancer. Both of these genes have restriction fragment length polymorphisms (RFLPs) that could account for differential expression or activity of variant forms. An EcoRI restriction site in the L-myc gene was previously reported to be a predictor of poor prognosis in Japanese lung cancer patients. There are several RFLPs in the p53 gene. In exon 4 there is a polymorphism that codes for either an arginine or proline residue at codon 72. We previously reported the frequency of DNA-RFLPs at these gene loci revealed by EcoRI and AccII respectively. Here we report results from a study comparing lung cancer cases (n = 31) with chronic obstructive pulmonary disease controls (n = 49). No association was found between these RFLPs and disease status. Previous observations that the frequencies of these RFLPs varied by race were confirmed. The p53 arginine allele was found to be more common in Caucasians (0.71) than African-Americans (0.50). The EcoRI restriction site present allele in L-myc was more frequent in African-Americans (0.71) than Caucasians (0.49). Thus, the allelic frequency for L-myc was similar in African-Americans to that reported for Japanese, and the allelic frequency for p53 was similar in Caucasians to that reported for Japanese. PMID: 7908608 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 998: Nucleic Acids Res. 1994 Mar 25;22(6):1012-7. Introduction of wild-type p53 in a human ovarian cancer cell line not expressing endogenous p53. Vikhanskaya F, Erba E, D'Incalci M, Broggini M. Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. Utilizing a temperature sensitive p53 mutant (pLTRp53cGval135) which expresses mutant p53 at 37 degrees C and a wild-type like p53 at 32 degrees C, we transfected a human ovarian cancer cell line (SKOV3) which does not express endogenous p53. Among the different clones obtained, we selected three clones. Two were obtained from simultaneous transfection of p53 and neomycin resistance expression plasmids (SK23a and SK9), the other was obtained from transfection experiments utilizing the neomycin resistance gene only (SKN). Introduction of mutant p53 did not alter the morphology or growth characteristics of this ovarian cancer cell line. Upon shifting to the permissive temperature, a dramatic change in morphology and growth rate was observed in SK23a and SK9 cells that is associated with the presence of a wild-type like p53. SKN and SKOV3 cells maintained at 32 degrees C did not change morphology and only slightly reduced proliferation. Both SK23a and SK9 cells did not show evidence of apoptosis when measured up to 72 hours of maintenance at 32 degrees C. In contrast to what observed in other cell lines, SK23a and SK9 cells maintained at 32 degrees C were not blocked in G1, but they were accumulated in G2-M. This accumulation was transient and could be due either to a blockade or to a delay in the G2 progression. No down-regulation of c-myc was observed in p53 expressing clones when shifted to the permissive temperature. In these conditions gadd45 mRNA expression was highly stimulated in SK9 and SK23a cells but not in SKN cells. In both clones Gas1 mRNA was not detected either at 37 degrees C or 32 degrees C. This system represents a new and useful model for studying the effect of the absence of p53 (SKOV3 or SKN), presence of mutated p53 (SK23a and SK9 kept at 37 degrees C) or wild type p53 (SK23a and SK9 kept at 32 degrees C) on the mechanism of response of cancer cells to DNA damaging agents. PMID: 8152906 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 999: Radiat Res. 1994 Mar;137(3):317-22. High levels of stable p53 protein and the expression of c-myc in cultured human epithelial tissue after cobalt-60 irradiation. Mothersill C, Seymour CB, Harney J, Hennessy TP. Radiation Science Centre, Dublin Institute of Technology, Ireland. When explants of human uroepithelium or esophageal epithelium are exposed to acute doses of radiation (cobalt-60), the cells which grow out to form the primary cultures show a number of abnormal features. These include the development of characteristic nonsenescent foci. These foci have previously been shown to be c-myc positive and to have an abnormal, tumor-like ultrastructure. Expression of c-myc and the level of stable p53 proteins have now been examined in these cultures 2 weeks after irradiation. Both proteins occurred in dividing cells at the growing edge of the explant and in the foci. The expression of c-myc appeared to be correlated with growth. As expected, variation between individual cultures of normal human cells were noted in the expression of stable p53 protein. Most control uroepithelial cell cultures were negative, but a small cohort showed a wide range of values. The control cultures from the esophageal tissues had high expression of p53, and this decreased marginally after irradiation. Cells positive for p53 were always in cycle and were usually positive for c-myc as well. It would appear from these results that the expression of c-myc and the stable form of the p53 protein occur in irradiated primary cultures of normal human cells both in foci which also express a number of abnormalities and in "edge" cells which are dividing. Cultures of unirradiated cells from esophagus and a small number of uroepithelial samples had high levels of p53. Possible reasons for this are discussed. PMID: 8146274 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1000: Cancer Res. 1994 Mar 1;54(5):1324-30. Alterations of the TP53 gene in human gliomas. Rasheed BK, McLendon RE, Herndon JE, Friedman HS, Friedman AH, Bigner DD, Bigner SH. Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710. Glial tumors of all grades and histological types from 72 adults and 48 children were analyzed for mutations of the TP53 gene, loss of heterozygosity (LOH) for 17p, and accumulation of TP53 protein to determine whether the incidence and type of TP53 alterations differ among tumors of different histological type and between tumors from adults and children. These tumors were also evaluated for LOH for chromosome 10 and for amplification of the epidermal growth factor receptor, C-MYC, N-MYC, GLI, platelet-derived growth factor receptor-alpha, and murine double minute 2 genes to determine the patterns of molecular alterations involved in the progression of these neoplasms. Seventeen of the 120 tumors contained mutations of the TP53 gene. One of the tumors with TP53 gene mutation was from one of the 48 patients less than 18 years of age. Twelve of the 17 tumors with mutations occurred among the 27 patients in the 18-45-year age group, while 4 tumors with mutations were among the 45 patients more than 45 years old. There was also an increased incidence of TP53 mutation in patients with anaplastic astrocytoma histology. However, no significant association between presence of TP53 mutation and patient survival was observed. These studies demonstrate that TP53 gene mutations are a common mechanism for glial cell neoplasms in the 18-45-year age group but are unrelated to progression and advanced histological grade. LOH for chromosome 10 and gene amplification, however, occurring in 82 and 40%, respectively, of glioblastoma multiforme, whether seen alone or along with TP53 gene alterations, are related to advanced histological grade of the tumor. In childhood gliomas, in contrast, TP53 gene alterations, LOH for 17p and 10q, and gene amplification are uncommon in tumors of all grades, suggesting that presently unknown mechanisms are responsible for the genesis and progression of these tumors. PMID: 8118823 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1001: Zhonghua Zhong Liu Za Zhi. 1994 Mar;16(2):88-92. [Studies on the reduction of malignant phenotypes in a highly metastatic human lung carcinoma--correlated changes of intercellular communication, cytoskeletons, oncogenes and antioncogene] [Article in Chinese] Zhang ZQ, Lin ZX, Lu YY. Beijing Institute for Cancer Research. Human lung giant cell carcinoma cell line PG is characterized by its highly metastatic (100%) behavior in nude mice. When compared with cultured normal human fetal lung cells, PG cells were deficient in gap junctional intercellular communication (GJIC) function as detected by Scrape Loading and Dye Transfer method. Tubulin immunofluorescent and rhodamine-phalloidin staining revealed disorganization of microtubules and disruption of stress fibers with appearance of reorganized F-actin-bodies in PG cells. Northern or dot blot hybridization results showed that PG expressed high levels of c-myc and c-Ha-ras oncogenes and low level of antioncogene P53. Southern hybridization demonstrated that PG also exhibited c-myc gene amplification. When PG was treated with calmodulin antagonist calmidazolium (CDZ, 100-200nmol/L) or a Chinese medicinal mixture L2 (3-13mg/ml), cell proliferation was inhibited, GJIC function restored, and microtubule network recovered. But only L2 was efficient in (1) improving the stress fiber organization, (2) inhibiting the colony formation in soft agar, (3) reduction of c-myc amplification and expression, and (4) up-regulation of P53 mRNA level. The correlation between markers of malignant phenotypes and the reversion of PG cells is discussed. PMID: 7924870 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1002: Leuk Res. 1994 Mar;18(3):149-60; discussion 161. Regrowth resistance in leukemia and lymphoma: the need for a new system to classify treatment failure and for new approaches to treatment. Preisler HD, Gopal V. Division of Hematology/Oncology, Rush Cancer Institute, Chicago, IL 60612. Treatment failure in drug sensitive malignancies is a complex phenomenon resulting from both drug resistance and from the rapid regrowth of malignant cells ('regrowth resistance'). Attempts to overcome regrowth resistance during the treatment of the aggressive lymphomas by increasing the frequency of cytotoxic therapy appears to have failed. An alternative approach of significant potential would be to administer biologically active agents to directly slow the regrowth of neoplastic cells between courses of full dose cytotoxic therapy. To facilitate this approach a new system for classifying treatment failure in the leukemias and lymphomas is needed so that the extent of regrowth resistance and the effects of treatment on regrowth resistance can be directly assessed. Accordingly, a new classification system is proposed. Publication Types: Review Review, Tutorial PMID: 7511189 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1003: Cancer Res. 1994 Feb 15;54(4):950-6. Fluctuations and ultrastructural localization of oncoproteins and cell cycle regulatory proteins during growth and apoptosis of synchronized AGF cells. Gazitt Y, Erdos GW. Department of Medicine, University of Arkansas for Medical Sciences, Little Rock 72205-7199. AGF cells were synchronized by blocking the cell cycle at the G1/S boundary with high concentrations of thymidine (thymidine block) for 11 h. Prolongation of the thymidine block from 11 h to 20 h resulted in apoptosis. Early changes in cellular and nuclear morphology were monitored by confocal microscopy, transmission electron microscopy, and scanning electron microscopy. The fluctuations in the levels of the proliferation cell nuclear antigen (PCNA), cyclin A, CDC-2, c-myc, and p53 proteins were monitored in synchronized cultures and in cells undergoing apoptosis by immunofluorescence staining, flow cytometry, and Western immunoblotting. When assayed by immunofluorescence staining and flow cytometry, the levels of cyclin A and PCNA increased about 2-fold during the S phase, and the level of CDC-2 was fairly constant during S and slightly decreased during late S/G2. The level of c-myc also increased about 2-fold during the S phase, whereas the level of p53 increased only slightly during S. Most importantly, however, the level of staining for c-myc, p53, cyclin A, CDC-2, and PCNA increased 50%-150% during apoptosis compared to the levels observed in cells at G1/S. In contrast, the levels of actin and vimentin, although increased during S, were decreased during apoptosis compared to the levels observed at G1/S. Western blot analysis of the steady state levels of PCNA, cyclin A, and CDC-2 revealed an increase in the levels of all three proteins during S, with higher levels of these proteins observed in apoptotic cells compared to the levels observed in cells at G1/S. Similarly, the levels of p53 and c-myc proteins increased during S and were also high in apoptotic cells. Interestingly, high levels of these two proteins were observed also in cells arrested at G1/S. AGF cells undergoing apoptosis were immunostained for c-myc, p53, PCNA, cyclin A, and CDC-2 and were viewed by confocal microscopy. Apoptotic cells exhibited increased staining for c-myc and p53 in the blebbing nuclei. Furthermore, we observed for the first time that CDC-2, cyclin A, and PCNA proteins were associated mostly with the plasma membrane and the cytoplasm of log phase cells. However, in cells undergoing apoptosis, these proteins were found exclusively in the nuclei of apoptotic cells. These results suggest a possible active role for c-myc, p53, and the cell cycle regulatory proteins in the process of nuclear blebbing and apoptosis. PMID: 7906198 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1004: Int J Cancer. 1994 Feb 1;56(3):457-8. The MDM2 oncogene is rarely amplified in human lymphoid tumors and does not correlate with p53 gene expression. Cesarman E, Liu YF, Knowles DM. Publication Types: Letter PMID: 8314334 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1005: Curr Opin Genet Dev. 1994 Feb;4(1):120-9. Oncogenes and cell death. Harrington EA, Fanidi A, Evan GI. Biochemistry of the Cell Nucleus Laboratory, Imperial Cancer Research Fund, London, UK. Several recent studies have implicated oncogenes and tumour suppressor genes in the regulation of programmed cell death (apoptosis). Lesions in the cell death pathway appear to be important in both carcinogenesis and the evolution of drug resistance in tumours. They include deregulated expression of genes such as bcl-2, loss of p53, and autocrine activation of anti-apoptotic signal transduction pathways. Paradoxically, a number of dominant oncogenes appear to act as potent inducers of apoptosis. This suggests that the pathways of cell proliferation and cell death may be tightly coupled, an idea that may have dramatic implications for models of oncogene co-operation and carcinogenesis. Publication Types: Review PMID: 8193531 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1006: Mol Carcinog. 1994 Feb;9(2):76-86. Combined effects of human papillomavirus-18 and N-methyl-N'-nitro-N-nitrosoguanidine on the transformation of normal human oral keratinocytes. Shin KH, Min BM, Cherrick HM, Park NH. School of Dentistry, University of California, Los Angeles. We immortalized oral keratinocytes by transfecting them with recombinant human papillomavirus (HPV) type 18 DNA and established three cell lines. These lines were morphologically different from their normal counterpart, contained integrated entire HPV-18 DNA, and expressed the viral E6/E7 genes. The cells contained less p53 protein and more c-myc mRNA than normal cells. However, they proliferated only in keratinocyte growth medium (KGM) containing low calcium and were not tumorigenic in nude mice. To test the hypothesis that tumors result from the combined effect of a "high-risk" HPV and chemical carcinogens in the human oral cavity, we exposed the immortalized cells to the chemical carcinogen N-methyl-N'-nitro-N-nitrosoguanidine. Three chemically transformed cell colonies were isolated. These cells (a) proliferated well in both KGM and Dulbecco's modified minimum essential medium containing physiological levels of calcium; (b) were capable of proliferating in nude mice; (c) contained intact, integrated HPV-18 sequences; (d) transcribed substantially more HPV-18 E6/E7, transforming growth factor-alpha, and c-myc than the immortalized counterpart; and (e) contained, like the immortalized counterpart, less wild-type p53 protein and DCC message. These data indicate that human oral keratinocytes can be transformed by sequential exposure of normal keratinocytes to a "high-risk" HPV and chemical carcinogens. PMID: 8142012 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1007: Hematol Oncol Clin North Am. 1994 Feb;8(1):1-14. Clinical relevance of breast cancer biology. Oza AM, Tannock IF. Department of Medicine, Princess Margaret Hospital, Toronto, Canada. Biological properties of breast cancer are reviewed in relation to their ability to provide information about etiology, prognosis, or response to therapy. The authors suggest guidelines for the rigorous and systematic evaluation of biologic factors in relation to the prognosis and treatment of breast cancer. Publication Types: Review Review, Tutorial PMID: 7512087 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1008: Int J Cancer. 1994 Jan 15;56(2):301-8. Establishment of human oral-cancer cell lines (KOSC-2 and -3) carrying p53 and c-myc abnormalities by geneticin treatment. Inagaki T, Matsuwari S, Takahashi R, Shimada K, Fujie K, Maeda S. Second Department of Pathology, Kobe University School of Medicine, Japan. Two cultured cell lines derived from human squamous-cell carcinomas were established through xenografted tumors in nude mice by "Geneticin" treatment, which allows to eliminate contaminated mouse fibroblasts and obtain enriched tumor cells at the early stage of cultivation. Line KOSC-2 and KOSC-3 were each derived from a squamous-cell carcinoma of the oral floor and of the lower gingiva, respectively. Both lines grew in a cobblestone pattern, demonstrating their epithelial heritage. Giemsa-banding patterns by chromosome analysis confirmed that both lines are of human origin. Molecular analysis of cancer-related genes, including the Ha-ras, c-myc and p53 genes, was performed. KOSC-3 cells showed co-over-expression of p53 and c-myc mRNA, in addition to p53 point mutation at codon 248 with transition from CGG to TGG. However, loss of heterozygosity (LOH) on chromosome 17 was detected in both lines by Southern blotting. These cell lines provide a model for elucidating the mechanism involving p53 inactivation and c-myc-gene over-expression. PMID: 8314315 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1009: Blood. 1994 Jan 15;83(2):452-9. Alterations of p53 and c-myc in the clonal evolution of malignant lymphoma. Chang H, Benchimol S, Minden MD, Messner HA. Ontario Cancer Institute, University of Toronto, Ontario, Canada. We derived the lymphoma cell lines OCI-Ly 13.1 and OCI-Ly 13.2 from a patient with non-Hodgkin's lymphoma at the time of presentation and during chemotherapy-resistant relapse. These lines were of T-cell phenotype and contained the identical T-cell receptor beta-chain rearrangement, indicating that both lines were members of the same malignant clone. The lines differed in their growth characteristics; OCI-Ly 13.1 grew slowly and required growth factors for colony formation, whereas OCI-Ly 13.2 grew rapidly and formed colonies without addition of growth factors. To test whether or not these biologic differences were associated with specific genetic changes, we evaluated the status of the c-myc and p53 genes of both cell lines. The p53 and c-myc genes of OCI-Ly 13.1 were in germline configuration and produced normal-sized transcripts. The p53 protein expressed in OCI-Ly 13.1 was recognized by the anti-p53 monoclonal antibody, PAb240, indicating a conformation typical of p53 proteins expressed by p53 alleles containing a missense mutation. However, sequencing studies of the entire p53 coding region did not reveal any point mutations. In contrast, the cell line OCI-Ly 13.2 contained structural abnormalities of both the c-myc and p53 genes. In addition, one of the p53 alleles was lost as determined by a cDNA probe for the p53 gene (17p 13.1) and the YNZ22.1 probe (17p 13.3). These changes resulted in the absence of p53 protein and mRNA in OCI-Ly 13.2 as detected by immunoprecipitation and Northern blot analysis, respectively. They may be a reflection of disease progression and may be associated with the altered behavior of the malignant cell population within the patient and in vitro. PMID: 8286743 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1010: Blood. 1994 Jan 1;83(1):191-8. Alterations of the p53 tumor suppressor gene in diffuse large cell lymphomas with translocations of the c-MYC and BCL-2 proto-oncogenes. Farrugia MM, Duan LJ, Reis MD, Ngan BY, Berinstein NL. Department of Immunology, University of Toronto, Ontario, Canada. Diffuse large cell lymphomas are aggressive tumors of B-cell origin. In some cases they arise from low-grade follicular lymphomas carrying the t(14;18) translocation, an event that leads to the overexpression of the BCL-2 gene product. More frequently, however, they lack the t(14;18) translocation. Rearrangements of the c-MYC proto-oncogene and mutations of the p53 tumor suppressor gene have also been documented in these lymphomas. This study examines the extent to which alterations in the BCL-2, c-MYC, and p53 genes co-exist within individual lymphomas. Eight diffuse large cell lymphoma cell lines and 11 diffuse large cell lymphoma tumors were assessed for genetic alterations in these three genes. Our results indicate that there is a heterogeneity in the oncogene/suppressor gene profile among diffuse large cell lymphomas. Two cell lines and one tumor carried alterations in all three genes, one cell line carried alterations of c-MYC and p53, and one primary tumor and one cell line carried p53 mutations and the t(14;18). Single alterations of BCL-2 and p53 were also observed. Another cell line had no alterations in any of these genes. The heterogeneity indicates that varied mechanisms may be involved in the generation of diffuse large cell lymphomas. PMID: 8274734 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1011: J Cancer Res Clin Oncol. 1994;120(3):143-8. Gene analysis of K-, H-ras, p53, and retinoblastoma susceptibility genes in human lung cancer cell lines by the polymerase chain reaction/single-strand conformation polymorphism method. Kashii T, Mizushima Y, Monno S, Nakagawa K, Kobayashi M. First Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan. In order to know the involvement of multiple gene alterations in the pathogenesis of human lung cancer, we examined the genes of K-, H-ras (codons 12, 13, 61), p53(exons 5-9) and the retinoblastoma susceptibility gene (RB)(exons 20-22) using the polymerase chain reaction/single-strand conformation polymorphism method in 32 human lung cancer cell lines (5 squamous-cell carcinomas, 10 adenocarcinomas, 3 large-cell carcinomas, 14 small-cell carcinomas). In 18 non-small-cell lung cancer lines, gene alterations were found in 4 for K-ras (22%), none for H-ras (0%), 4 for p53 (22%) and none for the RB (0%) gene. In 14 small-cell lung cancer (SCLC) lines, no gene alterations were found in K-ras (0%), or H-ras (0%), but 6 were found for p53 (43%) and 3 for the RB (21%) gene. Coincident abnormalities of K-ras and p53, or K-ras and RB genes were not found in any cell lines, and those of the p53 and RB genes were found in only 2 SCLC lines. No association was observed between these three gene alterations and N-myc amplification. Although the above three genes may be involved to some extent in the pathogenesis of lung cancer, more factors are required for its development. PMID: 8263009 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1012: Bull Soc Sci Med Grand Duche Luxemb. 1994;131(1):39-48. [Apoptosis and cancer] [Article in French] Duhem C, Ries F, Dicato M. Departement d'hemato-oncologie, Centre Hospitalier de Luxembourg. Publication Types: Review Review, Tutorial PMID: 8050118 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1013: Prog Clin Biol Res. 1994;385:117-22. The expression and modulation of proteins associated with physiological cell death in neuroblastoma cells. Ikegaki N, Kastumata M, Tsujimoto Y. Department of Pediatrics, University of Pennsylvania, Philadelphia 19104. PMID: 7972203 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1014: J Clin Pathol. 1994 Jan;47(1):9-14. p53, c-myc p62 and proliferating cell nuclear antigen (PCNA) expression in non-Hodgkin's lymphomas. Korkolopoulou P, Oates J, Kittas C, Crocker J. Department of Histopathology, East Birmingham Hospital. AIMS--To investigate the immunohistochemical expression of p53 protein in non-Hodgkin's lymphomas (NHL) and its relation to that of c-myc p62 oncoprotein and proliferating cell nuclear antigen (PCNA). METHODS--Paraffin wax embedded tissue from 90 non-Hodgkin's lymphomas (72 B cell and 18 T cell) was stained immunohistochemically for p53 protein, c-myc p62 oncoprotein, and PCNA using the monoclonal antibodies DO7, c-myc 1-9 E10, and PC-10, respectively. RESULTS--Of the non-Hodgkin's lymphomas studied, 55 (61%) stained positively for p53 protein. The proportion of positive cases increased from low grade non-Hodgkin's lymphoma and was higher in tumours of T cell origin. The percentage of positive cells (labelling index or LI) was significantly lower in low grade non-Hodgkin's lymphoma, but no difference was established between intermediate and high grade non-Hodgkin's lymphoma. In a large proportion of low grade non-Hodgkin's lymphoma the LI was below 1%. c-myc p62 immunoreactivity was identified in all cases. A significant positive correlation was established between p53 LI and c-myc p62 LI (rs = 0.453) as well as between p53 LI and PCNA LI (rs = 0.338). CONCLUSIONS--p53 immunoreactivity was present in about half the cases of non-Hodgkin's lymphoma and was related to the grade of malignancy and possibly to the B or T cell origin of the tumour. It was also associated with the proliferation state as expressed by PCNA LI and c-myc p62 expression, indicating that the expression of these three cell cycle-related genes might be interrelated. PMID: 7907610 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1015: Folia Neuropathol. 1994;32(4):199-203. Molecular changes involved in the carcinogenesis of brain tumors. Debiec-Rychter M, Liberski PP. Electron Microscopic Laboratory, School of Medicine Lodz. Current basic research on tumorigenesis suggests that the accumulation of multiple genetic defects underlies the progression of initiated cells toward malignancy. Molecular abnormalities associated with primary brain tumors include a wide variety of changes in tumor-suppressor genes, proto-oncogenes and growth factors. A well-known tumor-suppressor gene, p53 gene, is located on the short arm (p) of chromosome 17 and consists of 11 exons transcribed into a 2.2-2.5 kb messenger (m) RNA that encode for a 53 kDa protein. Its alterations are associated with carcinogenesis of astrocytic tumors. Recent evidence suggests also that the p53 protein may function through promoting the expression of the recently discovered gene, WAF1/Cipl. Loss of chromosome 10 was frequently observed in glioblastoma. Southern blot analysis of glioblastomas revealed that 72% have the chromosome 10 loss and that 38% had amplification of the epidermal growth factor receptor (EGFR) gene. Autocrine stimulation of cell growth requires the presence of both growth factors and their receptors. Other genetic alterations in gliomas include elevated expression of the c-myc, Ha-ras, and c-fos oncogenes with a trend to increase in higher malignant grades. Publication Types: Review Review, Tutorial PMID: 7889330 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1016: Antibiot Chemother. 1994;46:117-24. Molecular pathogenesis of AIDS-related lymphomas. Gaidano G, Dalla-Favera R. Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, N.Y. Publication Types: Review Review, Tutorial PMID: 7826032 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1017: J Neurooncol. 1994;19(3):259-68. Negative effects of wild-type p53 and s-Myc on cellular growth and tumorigenicity of glioma cells. Implication of the tumor suppressor genes for gene therapy. Asai A, Miyagi Y, Sugiyama A, Gamanuma M, Hong SH, Takamoto S, Nomura K, Matsutani M, Takakura K, Kuchino Y. Biophysics Division, National Cancer Center Research Institute, Tokyo, Japan. Human (U251, U87, U343) and rat glioma cell lines (C6, 9L) were examined by the reverse transcriptase-polymerase chain reaction and subsequent nucleotide sequencing analysis to see whether they express wild type (wt)-p53 or mutated form (mut)-p53 messages. Results showed that U87, U343, and C6 cells expressed wt-p53 messages whereas U251 and 9L cells expressed mut-p53 messages. All these cell lines were transfected with wt-p53 cDNA or the s-myc gene linked to the mouse mammary tumor virus (MMTV) promoter. Of several G418-resistant clones obtained from each transfection, a few expressed the s-Myc or wt-p53 proteins. Independent of mutations in the intrinsic p53 gene, the cellular growth in vitro and tumorigenicity in nude mice of these clones were drastically suppressed, the extent of suppression being correlated with the expression level of the transfected gene. Flow-cytometric analysis demonstrated that both p53 and s-Myc arrested the cell cycle at the G1/S boundary. These data suggest that these genes having negative effects on tumor cell proliferation could be used in gene therapy of gliomas, which are caused by alteration of the p53 gene or by some other genetic change. PMID: 7807177 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1018: Cell Mol Biol Res. 1994;40(7-8):699-706. Position and orientation independent transactivation by c-Myc. Packham G, Bello-Fernandez C, Cleveland JL. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. The c-myc oncogene c-Myc is commonly activated in cancer and transactivates gene expression by binding to CACGTG DNA sequences as a heterodimeric complex with Max. The ornithine decarboxylase (ODC), p53, prothymosin alpha and ECA39 promoters are transactivated by c-Myc, and are considered direct targets, as activation is mediated by CACGTG sequences. Interestingly, the c-Myc-responsive CACGTG sequences in the p53, prothymosin alpha, ECA39 and murine ODC genes are all downstream of the RNA CAP site, suggesting that downstream sequences are preferred c-Myc targets. Using a series of heterologous reporter constructs, we have tested the effects of position and orientation of c-Myc-responsive CACGTG sequences on c-Myc's ability to activate transcription. A single binding site conferred c-Myc-responsiveness independent of position and orientation, and over distances of 1.7 kbp. The extent of transactivation was not significantly influenced by position of the responsive elements. By contrast, the extent of transactivation was dependent upon the number of c-Myc binding sites. The results demonstrate that c-Myc activates transcription independent of position and orientation and that considerable flexibility exists in the interaction of c-Myc transactivation domains with the general transcription machinery. PMID: 7787888 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1019: Cell Mol Biol Res. 1994;40(7-8):603-12. Apoptosis and the cell cycle. Chiarugi V, Magnelli L, Cinelli M, Basi G. Laboratory of Molecular Biology, University of Florence, Firenze, Italy. This brief review examines the strict relationships between cell apoptosis and G1 cyclins. It has been shown that the basic role of G1 cyclins is in regulating G1 progression and G1/S transition (the critical cycle point for cell program decisions, including apoptosis) a fatal program for cells unable to bypass G1/S checkpoint 1. Notably, both of the two giant regulators of checkpoint 1 (i.e., p105RB [retinoblastoma oncosuppressor-encoded protein] and p53 dependent WAF1/CIP1) are influenced by or influence G1 cyclins: cyclin E/cdk2 kinase complexes hyperphosphorylate p105RB, induce E2F release, and free G1 exit. On the other hand, p21-WAF1/CIP1 is an inhibitor of cyclin-dependent kinases blocking cells at G1/S. Thus, G1 cyclin activity appears as a conditio sine qua non for G1 exit and apoptosis escape. Publication Types: Review Review, Tutorial PMID: 7787878 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1020: Postepy Hig Med Dosw. 1994;48(6):663-75. Erratum in: Postepy Hig Med Dosw 1995;49(4):583. [Diversity of signal transduction pathways which induce apoptosis of thymocytes. Role of bcl-2, pim-1, c-myc and p53 genes in selection processes of thymocytes] [Article in Polish] Matuszyk J, Strzadala L. Laboratorium Immunologii Komorkowej Instytutu Immunologii i Terapii Doswiadczalnej PAN we Wroclawiu. There are independent signaling pathways which transmit apoptotic signals in thymocytes. c-Myc and p53 proteins participate in the apoptosis induction, whereas Bcl-2 and Pim-1 proteins inhibit complex apoptotic machinery. Publication Types: Review Review, Tutorial PMID: 7675728 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1021: Verh Dtsch Ges Pathol. 1994;78:36-7. [Proliferative activity and defective replication in breast cancer] [Article in German] Kreipe H, Zeidler R, Kneitz H, Feist H. Institut fur Pathologie, Universitat Wurzburg. The highly proliferating phenotype of mammary carcinoma is known to be associated with a particularly aggressive clinical course. We have been interested in the underlying molecular causes that give rise to the increased proliferative activity Proliferative activity was determined immunohistochemically by the detection of topoisomerase II-alpha (Ki-S1). The subgroup of highly proliferating tumors with a Ki-S1 index exceeding 30% was characterized by a high frequency of c-myc amplification and aberrant p53 expression, whereas tumors, with a low mitotic activity rarely exhibited gene amplification or an altered p53 expression. We conclude, that the highly proliferating phenotype is not capable of regular replication and tends to develop gene amplifications. One of the causes might be a defective cell cycle control by p53. Publication Types: Review Review, Tutorial PMID: 7534009 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1022: Virchows Arch. 1994;424(4):403-9. Cytomorphological, cytogenetic, and molecular biological characterization of four new human renal carcinoma cell lines of the clear cell type. Gerharz CD, Ramp U, Olert J, Moll R, Storkel S, Marx N, Gabbert HE. Department of Pathology, University Hospital of Dusseldorf, Germany. Four new permanent cell lines (RCC-A, -B, -C, and -D) derived from different human renal cell carcinomas of the clear cell type were established in tissue culture. The cell lines displayed characteristic differences in cell size and shape, which allowed individual identification by phase contrast microscopy. Ultrastructurally, the cell lines exhibited varying amounts of cytoplasmatic glycogen and lipid. Immunohistochemistry revealed co-expression of vimentin and cytokeratin in all cell lines. The mean population doubling time ranged from 27 h (RCC-A) to 104 h (RCC-D). RCC-B and -C cells produced slowly growing tumours after heterotransplantation into nude mice, whereas RCC-A and RCC-D cells were non-tumorigenic. The modal chromosome number was either near-diploid (RCC-A, -B, and -C) or near triploid (RCC-D). Clonal abnormalities affecting the short arm of chromosome 3 were seen in all cell lines. Northern blot analysis revealed no expression of the proto-oncogenes c-fos, c-ros, and c-mos, whereas c-Ki-ras expression was observed in all cell lines. Expression of c-myc was observed in RCC-A, RCC-B, and RCC-D cells, whereas c-raf expression could be detected in RCC-B and RCC-D. Tumour suppressor gene p53 mRNA was observed in the cell line RCC-D. PMID: 7515757 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1023: Cancer. 1993 Dec 15;72(12):3732-8. Infrequency of ras, p53, WT1, or RB gene alterations in Wilms tumors. Waber PG, Chen J, Nisen PD. Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235-9063. BACKGROUND. Alteration of the ras family of oncogenes and of the tumor suppressor genes p53 and RB are the most common genetic events in human tumors. Although there have been no reports of the prevalence of these alterations in Wilms tumors, overexpression of the N-myc and insulin-like growth factor-II (IGF-II) genes have been observed, and alteration of another tumor suppressor gene (WT1) has been demonstrated. METHODS. Forty-four Wilms tumor specimens were tested for the presence of N-, K-, and H-ras mutations in codons 12, 13, and 61 by single-strand conformation polymorphism (SSCP) analysis and direct DNA sequence analysis. Sixteen tumors were tested for abnormalities of WT1 by Southern and northern blot analysis and reverse transcriptase polymerase chain reaction (RT-PCR). N-myc, c-myc, WT1, and IGF-II mRNA expression was measured in 16 tumors by Northern blot analysis. Thirty-eight tumors were screened for p53 mutations by SSCP analysis and direct DNA sequence analysis. Nine tumors were analyzed for loss of heterozygosity (LOH) of RB. RESULTS. Although the authors confirmed that N-myc and IGF-II are overexpressed in Wilms tumors, no mutations of ras family, p53, or RB genes were identified, and no gross alterations of WT1 were detected by Southern or Northern blot analysis. CONCLUSIONS. These findings suggest that H-ras, K-ras, N-ras, p53, and RB are not involved in the pathogenesis of Wilms tumor. PMID: 8252491 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1024: Cell Mol Biol (Noisy-le-grand). 1993 Dec;39(8):855-62. Effects of DNA damaging agents on gene expression in two human cancer cell lines. Vikhanskaya F, D'Incalci M, Broggini M. Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. In two human cancer cell lines, the breast mcf-7 and the T-cell leukemia MOLT4, we investigated the cytotoxicity of four antineoplastic agents having different mechanisms of action. We selected doxorubicin as a DNA-topoisomerase II inhibitor, FCE24517 (a Distamycin A derivative) as a DNA minor groove binder with specificity for AT bases, melphalan as an alkylating agent and cis-platinum as an alkylating agent able to form DNA-intrastrand crosslinks. From the cytotoxicity experiments a moderately toxic (less than 10% of growth inhibition) and a highly toxic (about 75% growth inhibition) dose were selected to evaluate the expression of genes involved in cell proliferation and in cell response to extracellular insults. The expression was evaluated at early times (60 min.) and 24 hrs. after treatment. At the concentrations utilized in both cell lines we could not find any alteration in the expression of p53, gas-1 and heat shock 70. After melphalan treatment down regulation of c-myc and of the H2A histone was seen at high doses, while no significant alteration of their expression was seen with the other drugs. PMID: 8298434 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1025: Oncogene. 1993 Dec;8(12):3427-31. Wild-type p53-triggered apoptosis is inhibited by bcl-2 in a v-myc-induced T-cell lymphoma line. Wang Y, Szekely L, Okan I, Klein G, Wiman KG. Department of Tumor Biology, Karolinska Institute, Stockholm, Sweden. Using a temperature sensitive p53 construct (ts p53), we have earlier shown that expression of wild-type (wt) p53 triggers apoptosis in a v-myc-induced T-cell lymphoma line that lacks endogenous p53, and in a Burkitt lymphoma line that carries mutant p53. We have suggested that apoptosis is elicited by the contradictory signals emanating from the constitutively activated myc gene and the growth arresting signal of wt p53 (Ramqvist et al., 1993; Wang et al., 1993). Work in other laboratories has shown that constitutive c-myc expression can induce apoptosis when cell proliferation is inhibited due to the lack of growth stimulating factors. Expression of bcl-2 could inhibit apoptosis. In order to test whether p53-induced apoptosis can be prevented by bcl-2, we have introduced a retrovirally driven bcl-2 construct into our v-myc-induced murine T-cell lymphoma line, previously transfected with ts p53. About 90% of the parental ts p53 transfected cells died of apoptosis within 3 days after induction of wt p53 expression at 32 degrees C. Two clones of ts p53/bcl-2 double transfectants that expressed high levels of bcl-2 from the introduced construct were completely protected from apoptosis, following transfer of the cells to 32 degrees C. One clone that expressed the exogenous bcl-2 only at a low level was partially protected from wt p53-induced apoptosis. Clones of the parental ts p53 carrying cells transfected with the puromycin resistance gene vector, without the bcl-2 gene underwent 90% apoptosis. These results suggest that bcl-2 may prevent apoptosis in cells simultaneously exposed to the proliferation-stimulating effect of activated myc and the growth arresting signal of wt p53. PMID: 8247547 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1026: Mol Cell Biol. 1993 Dec;13(12):7942-52. Complementation by wild-type p53 of interleukin-6 effects on M1 cells: induction of cell cycle exit and cooperativity with c-myc suppression. Levy N, Yonish-Rouach E, Oren M, Kimchi A. Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel. Stable transfection of M1 myeloid leukemia cells with a temperature-sensitive mutant of p53 results in two phenomena that are manifested exclusively at the permissive temperature. On one hand, activation of wild-type p53 by the temperature shift induced an apoptotic type of cell death which could be inhibited by interleukin-6 (IL-6) (E. Yonish-Rouach, D. Resnitzky, J. Lotem, L. Sachs, A. Kimchi, and M. Oren, Nature 352:345-347, 1991). On the other hand, as reported in this work, activated p53 complemented the antiproliferative effects of IL-6 in M1 cells. A shift to the permissive temperature concomitant with or early after IL-6 treatment imposed a novel pattern of cell cycle arrest in which about 95% of the cells were retained within a G0-like quiescent state. This phase was characterized by 2N DNA content and low RNA and protein content. On the molecular level, activation of wild-type p53 transrepressed the c-myc gene but not the cyclin A, D1, or D2 gene, which are all independently suppressed by IL-6 in M1 cells. To further analyze whether c-myc inhibition mediates or complements p53 effects, the p53-transfected M1 cells were infected with a retroviral vector expressing deregulated c-myc, refractory to p53 or IL-6 action. It was found that the process of cell death was not interrupted at all in these M1 c-myc-p53 double transfectants, suggesting that the transrepression of c-myc is not a major obligatory event mediating p53-induced cell death. In addition, some of the antiproliferative effects of activated p53, manifested in the presence of IL-6, could still be transmitted in the background of constitutive c-myc. Yet the context of deregulated c-myc interfered with the final accumulation of cells within a G0-like phase, suggesting complementary interactions between the outcome of p53 activation and of c-myc suppression in the control of cell cycle arrest. PMID: 8247009 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1027: Clin Biochem. 1993 Dec;26(6):439-47. Cellular oncogenes and suppressor genes as prognostic markers in cancer. Duffy MJ. Nuclear Medicine Department, St. Vincent's Hospital, Dublin, Ireland. Activation of cellular or c-oncogenes and loss of function of suppressor genes appears to be the key event in the formation of most human cancers. Altered forms of these genes or their protein products have the potential to provide a new generation of cancer markers. As cancer markers, the most useful application of c-oncogenes and suppressor genes so far, has been in providing prognostic information. The correlation of N-myc gene amplification with poor prognosis in neuroblastoma was one of the first examples of prognostic data supplied by a c-oncogene. Most, but not all investigators, find that either amplification or increased expression of c-erbB-2 gene correlates with poor prognosis in breast cancer. Other potential prognostic markers in breast cancer include amplification of the c-myc gene, and increased expression of both EGFR and p53 protein. Although c-oncogenes and suppressor genes have the potential to supply prognostic information in a broad range of cancers, many of the results are still preliminary with conflicting conclusions. Publication Types: Review Review, Tutorial PMID: 8124858 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1028: Am J Vet Res. 1993 Dec;54(12):2010-4. Specific expression of cellular oncogenes c-myc and c-myb in T-cell lines established from three types of bovine lymphosarcomas. Ishiguro N, Matsui T, Shinagawa M. Department of Veterinary Public Health, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan. Expression of cellular oncogenes in 3 lymphoid cell lines, BTL-PC3 (BoCD2-, BoCD4-, BoCD8-, BoWC1+), BLS1 (BoCD2+, BoCD4-, BoCD8-, BoWC1+) and BLT2 (BoCD2-, BoCD4-, BoCD8-, BoWC1-), which have been established from calf, skin, and thymic types of lymphosarcomas, respectively, were analyzed by DNA-RNA (northern blot) hybridization. To determine specific expression of oncogenes involved in malignant transformation of the lymphoid cells, cellular RNA was isolated from bovine tumor cell lines, BTL-PC3, BLS1, and BLT2, and from Madin Darby bovine kidney cells used as a control for bovine cell lines. The RNA was hybridized against 5 viral oncogene probes (v-jun, v-myc, v-erbB, v-erbA and v-fes), 6 human cellular oncogene probes (N-ras, c-Blym-1 c-erbB-2, c-fos, c-myb and c-abl), human p53 tumor suppressor gene, and bovine LDH-A gene probes. Line BTL-PC3 expressed 2.4-kilobase (kb) c-myc and 4.0- and 3.6-kb c-myb transcripts, and line BLT2 expressed a 3.8-kb c-myb transcript, but line BLS1 expressed no message for the oncogenes tested. Specific transcripts of p53 were found in BTL-PC3 and BLT2 lines, but not in BLS1. Madin Darby bovine kidney cell line expressed multiple cellular oncogenes, c-jun, c-myc, and c-fos, and p53 genes. Southern blot hybridization did not reveal abnormal DNA rearrangements associated with the expressed oncogenes (c-myc and c-myb) in the 3 bovine tumor lines. (ABSTRACT TRUNCATED AT 250 WORDS) PMID: 8116930 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1029: Ann N Y Acad Sci. 1993 Nov 30;698:21-30. Frequent mutations in breast cancer. Callahan R, Gallahan D, Smith G, Cropp C, Merlo G, Diella F, Liscia D, Lidereau R. National Cancer Institute, Bethesda, Maryland 20892. Publication Types: Review Review, Tutorial PMID: 8279759 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1030: Cancer Res. 1993 Nov 1;53(21):5284-8. Mutations of the p53 gene are involved in Ewing's sarcomas but not in neuroblastomas. Komuro H, Hayashi Y, Kawamura M, Hayashi K, Kaneko Y, Kamoshita S, Hanada R, Yamamoto K, Hongo T, Yamada M, et al. Department of Pediatric Surgery, University of Tokyo, Japan. We have investigated the frequency of p53 gene mutations in Ewing's sarcoma (ES) and neuroblastoma (NB) by using polymerase chain reaction-single strand conformation polymorphism analysis for genomic DNA or complementary DNA generated from total RNA. Mutations of the p53 gene were found in six of seven ES cell lines: a missense mutation of TGC (Cys)-->TAC (Try) at codon 141 in one, a missense mutation of CGT (Arg)-->TGT (Cys) at codon 273 in one, a missense mutation of TGC (Cys)-->TTC (Phe) at codon 176 in three, and one base deletion of CGC-->CG at codon 283 in one. Further analysis of 14 ES and related primary tumors showed mutations of the p53 gene in only two: one base insertion of CCG-->CCCG at codon 152 in one and a missense mutation of GGC (Gly)-->GTC (Val) at codon 154 in the other. Both of the two tumors were obtained from patients with an advanced stage disease. Three of the eight ESs with mutations of the p53 gene showed the same missense mutation at codon 176, suggesting the mutational hot spot of the p53 gene in ESs. In contrast to ES, none of 6 NB cell lines or 48 NB tumors including advanced-stage ones with or without N-myc amplification showed any aberration of the p53 gene. Our findings suggest that mutations of the p53 gene in ES might represent late genetic events related to tumor progression, and that aberrations of the p53 gene might not be involved in the development or the progression of NB. PMID: 8221663 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1031: Zhonghua Zhong Liu Za Zhi. 1993 Nov;15(6):408-11. [Multiple gene alterations in human esophageal squamous cell carcinoma] [Article in Chinese] Liang YY. Cancer Institute, Chinese Academy of Medical Sciences, Beijing. In 45 human esophageal squamous cell carcinomas, 29 showed alterations of EGFr, c-myc, int-2, Rb and p53 gene by Southern blot hybridization, a frequency of 15.6%, 31.1%, 35.6%, 22.2%, 6.7%, respectively. Among these cases, 16 cases showed two or multiple gene changes, and most of them were of II-III stage. The results suggest that gene alterations may be related to pathological stages of the disease. The poorer the differentiation of the tumor, the more gene changes were accumulated. We did not find association between the presence of metastasis in lymph nodes and the gene alterations. PMID: 8200275 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1032: Jpn J Cancer Res. 1993 Nov;84(11):1159-64. Analysis of genetic alterations related to the development and progression of breast carcinoma. Nagayama K, Watatani M. First Department of Surgery, Kinki University School of Medicine, Osaka. To study genetic alterations related to the development and/or progression of breast carcinoma, we examined amplification of the ERBB2, INT2, and MYC genes, as well as loss of heterozygosity (LOH) at loci on 11p, 16q, 17p (D17S5 and TP53), 17q (D17S74 and NME1), and 18q by restriction fragment length polymorphism analysis. The subjects were 26 patients with small breast carcinomas (< or = 2 cm) and 88 patients with larger breast carcinomas (2 to < 5 cm). All patients were free of distant metastasis. As tumor diameter increased, the frequency of oncogene amplification and LOH at all loci except D17S5 increased. However, there was no relationship between tumor diameter and amplification of specific oncogenes or allelic loss at specific loci. LOH at D17S5 was detected in 40% of small breast carcinomas (< or = 2 cm) and 43% of larger breast carcinomas (2 to < 5 cm). There was a significant correlation of LOH at D17S5 with INT2 amplification or with LOH on 11p, 16q, and 18q. These findings suggest that LOH at D17S5 may be involved in the early stage of breast carcinoma development, while INT2 amplification and LOH at 11p, 16q, and 18q appear to be genetic alterations that occur with tumor progression. In addition, as lymph node metastases were significantly related to amplification of the ERBB2 and MYC genes, and LOH of the NME1 gene, these genetic alterations may play a role in the mechanism of lymph node metastases. PMID: 7903963 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1033: Cancer Res. 1993 Oct 15;53(20):4811-6. HPV-16, tobacco-specific N-nitrosamine, and N-methyl-N'-nitro-N-nitrosoguanidine in oral carcinogenesis. Kim MS, Shin KH, Baek JH, Cherrick HM, Park NH. School of Dentistry, University of California, Los Angeles. We previously immortalized human oral keratinocytes by transfection with recombinant human papillomavirus type 16 (HPV-16) DNA and established two cell lines. These transfected cells were morphologically different from the normal counterpart, contained intact HPV-16 DNA in an integrated form, and expressed numerous viral genes. These cells contained lower levels of wild-type p53 protein and higher levels of c-myc mRNAs compared to normal cells. However, they proliferated only in keratinocyte growth medium containing a low level of calcium and were not tumorigenic in nude mice. A HPV-16-immortalized cell line was exposed to either 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone or N-methyl-N'-nitro-N-nitrosoguanidine. Four chemically transformed cell colonies were isolated. These cells proliferated well in Dulbecco's minimum essential medium containing a physiological level of calcium. They contained, similar to the immortalized counterpart, integrated HPV-16 sequences and lower levels of both wild-type p53 protein and DCC messages compared to normal cells. Among the chemically transformed cells, two colonies obtained from 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone exposure demonstrated an enhanced proliferation capacity in nude mice and transcribed a substantially higher amount of HPV-16 E6/E7, epidermal growth factor receptors, and c-myc genes compared with the immortalized counterpart. These experiments indicate that malignant transformation of oral keratinocytes can be caused by a sequential combined effect of "high risk" HPV and tobacco-related carcinogens. PMID: 8402666 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1034: Blood. 1993 Oct 15;82(8):2289-95. p53 mutations are associated with histologic transformation of follicular lymphoma. Lo Coco F, Gaidano G, Louie DC, Offit K, Chaganti RS, Dalla-Favera R. Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY 10032. The majority of low-grade non-Hodgkin's lymphomas (NHL) undergo clinical progression toward intermediate- and high-grade lymphomas. This progression is often associated with histologic transformation from follicular to diffuse-type NHL. The pathogenetic mechanisms underlying this evolution are presently unknown. In this study, we have analyzed the role in NHL progression of relevant genetic lesions affecting proto-oncogenes and tumor suppressor genes. Sequential biopsies from 21 patients with clinical progression with (5 cases) or without (16 cases) evidence of histologic transformation were analyzed for karyotypic changes, c-myc rearrangements and deletions affecting 6q27 by Southern blot analysis, and p53 mutations by single-strand conformation polymorphism (SSCP) analysis coupled with direct sequencing of polymerase chain reaction-amplified products. No novel cytogenetic aberration was detected in association with progression, and all samples analyzed displayed a normal c-myc gene. Mutations of the p53 gene were detected in 4 of 5 cases displaying histologic transformation from follicular to diffuse-type NHL and in none of the 16 cases displaying clinical progression in the absence of histologic transformation. In 1 of these positive cases, the same mutation was also present in the pretransformation biopsy, correlating with the presence of diffuse-type areas within a predominant follicular pattern. In 1 of these cases, a deletion of 6q27 was also detected in the posttransformation biopsy along with a p53 mutation. These findings indicate that p53 mutations are associated with and may be responsible for histologic transformation of follicular lymphoma. PMID: 8400281 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1035: Cancer Res. 1993 Sep 1;53(17):4053-8. Mutation of the p53 gene in neuroblastoma and its relationship with N-myc amplification. Imamura J, Bartram CR, Berthold F, Harms D, Nakamura H, Koeffler HP. University of California, School of Medicine, Los Angeles 90024. Mutation of the p53 tumor suppressor gene frequently occurs in a variety of tumors including lung, breast, gastrointestinal, and brain, as well as lymphomas-leukemias. Neuroblastoma, one of the most common solid tumors in childhood, often has amplification of the N-myc gene. We examined for mutations of the p53 tumor suppressor gene by single-strand conformational polymorphism using polymerase chain reaction products and direct sequencing method in neuroblastoma; in addition, we assessed the relationship between p53 mutation and N-myc gene amplification in the disease. Of 86 DNA samples from patients with neuroblastoma, two mutations (2%) were found in the coding region of the p53 gene. Each mutation caused a substitution of amino acid residues. One mutation was located in exon 5, and another was in exon 6. N-myc gene was amplified in 26% of the samples. No p53 mutations were found in neuroblastoma samples with N-myc amplification. In the two individuals, p53 mutations appeared as their disease became more progressive. The neurofibromatosis 1 (NF1) gene is frequently abnormal in another neural disorder, neurofibromatosis type 1; in addition, a potential mutational hot spot of NF1 at lysine at codon 1423 has been identified in several types of tumors. Using single-strand conformational polymorphism, we were unable to detect an abnormality in this region of NF1 in 50 samples of neuroblastoma. The data suggest that p53 mutations occasionally are associated with progression of neuroblastomas, and tumorigenetic influences of mutant p53 may differ from those of N-myc. PMID: 8358734 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1036: J Virol. 1993 Sep;67(9):5226-34. Large E1B proteins of adenovirus types 5 and 12 have different effects on p53 and distinct roles in cell transformation. van den Heuvel SJ, van Laar T, The I, van der Eb AJ. Laboratory of Molecular Carcinogenesis, Sylvius Laboratory, University of Leiden, The Netherlands. The formation of complexes between oncoproteins of DNA tumor viruses and the cellular protein p53 is thought to result in inactivation of the growth suppressor function of p53. In cells transformed by nononcogenic human adenovirus type 5 (Ad5), the 55-kDa protein encoded by E1B forms a stable complex with p53 and sequesters it in the cytoplasm. However, the homologous 54-kDa protein of highly oncogenic Ad12 does not detectably associate with p53. Yet in Ad12-transformed cells, p53 is metabolically stable, is present at high levels in the nucleus, and contributes to the oncogenicity of the cells. Such properties have previously been described for mutant forms of p53. Here, we show that stable p53 in Ad12-transformed cells is wild type rather than mutant and that stabilization of p53 is a direct consequence of the expression of the Ad12 E1B protein. We also compared the effects of the E1B proteins on transformation of rodent cells by different combinations of oncogenes. A synergistic interaction was observed for the gene encoding the 54-kDa E1B protein of Ad12 with myc plus ras oncogenes, resembling the effect of mutant p53 on myc plus ras. In contrast, the Ad5 55-kDa E1B protein strongly inhibited transformation by myc plus ras but stimulated transformation by E1A plus ras. The data are explained in terms of different interactions of the two E1B proteins with endogenous p53. The results suggest that in cultured rat cells, endogenous wild-type p53 plays an essential role in cell proliferation, even in the presence of myc plus ras. The dependence on p53 is lost, however, when the adenovirus E1A oncogene is present. PMID: 8350396 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1037: Anticancer Res. 1993 Sep-Oct;13(5A):1341-56. Genomic abnormalities in hepatocarcinogenesis. Implications for a chemopreventive strategy. Pascale RM, Simile MM, Feo F. Istituto di Patologia Generale dell' Universita di Sassari, Italy. Carcinogenesis is a complex process characterized by the cumulative activation of various oncogenes and the inactivation of suppressor genes. Epigenetic mechanisms are also involved. Mutational activation of ras family genes occurs in most spontaneous or carcinogen-induced liver tumors, in susceptible mice, and less frequently in preneoplastic lesions. This suggests a pathogenetic role of these changes in hepatic carcinogenesis, in the mouse. Overexpression of various growth-related genes occurs in preneoplastic tissue during rat liver carcinogenesis, but mutational activation of protooncogenes, notably of ras family genes, seems to be a late and rare event, while c-myc amplification is a late but frequent event in both rodent and human carcinogenesis. However, mutation of the suppressor p53 gene has been found in relatively early preneoplastic lesions in rat liver, and it may be frequently seen in human hepatocellular carcinomas. The possibility that this mutation is involved in the initiation stage of liver carcinogenesis is an attractive hypothesis which needs further evaluation. DNA hypomethylation is involved in carcinogenesis, but the mechanisms underlying this effect are still elusive. Hypomethylation of growth-related genes is associated with their overexpression and this could favor overgrowth of preneoplastic liver tissue. Decrease in S-adenosyl methionine/S-adenosylhomocysteine (SAM/SAH) ratio occurs in the liver of rats fed a methyl deficient diet, which is a carcinogenic treatment, and in preneoplastic liver tissue, developing in initiated/promoted rats fed an adequate diet. The role of low SAM/SAH ratio in carcinogenesis is substantiated by the tumor chemopreventive effect of lipotropic compounds. Treatment with exogenous SAM prevents the development of preneoplastic and neoplastic lesions in rat liver. This is associated with recovery of SAM/SAH ratio, DNA methylation and inhibition of growth-related gene expression. SAM effect on prenoplastic cell growth is abolished by 5-azacytidine, a hypomethylating agent, indicating the involvement of DNA methylation. The possibility that in SAM-treated rats, methylation and inhibition of the expression of growth-related genes is implicated in growth restraint is attractive and should be further evaluated. Modulation of rat liver carcinogenesis by influencing gene expression through DNA methylation or other epigenetic mechanisms could be a new approach to chemoprevention of these tumors. Publication Types: Review Review, Tutorial PMID: 8239505 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1038: Tumori. 1993 Aug 31;79(4):235-43. Genetic events responsible for colorectal tumorigenesis: achievements and challenges. Kopnin B. Institute of Carcinogenesis, Cancer Research Center, Moscow. Colorectal carcinogenesis is a multistep process that is accompanied by accumulation of changes in proto-oncogenes and tumor-suppressor genes. APC/MCC, RAS, DCC, p53 mutations and/or allelic losses, hyperexpression of c-MYC and RB genes, as well as other genomic alterations appear at characteristic stages of tumor development and are observed in most neoplasms. However, consideration of each of these abnormalities leaves many unanswered questions. The striking data on recurrent amplification of the RB tumor-suppressor gene as well as suppressive activities of protein kinase C and activated RAS genes, at least in some colon carcinoma cell lines, suggest the unusual effects of some signalling pathways in colonic epithelial cells. The results obtained to date indicate that distinct sets of genetic changes may underlie the development of colorectal tumors. Publication Types: Review Review, Tutorial PMID: 8249174 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1039: J Urol. 1993 Aug;150(2 Pt 1):490-4. p53 and c-myc expression in stage A1 prostatic adenocarcinoma: useful prognostic determinants? Fox SB, Persad RA, Royds J, Kore RN, Silcocks PB, Collins CC. Department of Pathology, University of Sheffield Medical School, United Kingdom. Forty-five stage A1 prostatic adenocarcinomas from patients with a mean age of 65 years were examined for p53 and c-myc expression to determine whether the presence or absence of these proteins could predict tumor behavior. Thirteen (6 of 45) and seventy-three percent (33 of 45) of cases were respectively p53 and c-myc positive. p53 expression was confirmed to the tumor cells, whereas c-myc immunoreactivity was present in both malignant and surrounding hyperplastic prostate. Statistical analysis showed that although p53 and c-myc expression were positively correlated, expression of neither nuclear protein was associated with a significantly worse survival (p53: p = 0.0791 exact two-tailed; c-myc: p = 0.738 exact two-tailed). These results suggest that while both p53 and c-myc may play a role in prostatic carcinogenesis, neither appears to identify patients who may benefit from treatment in stage A disease. PMID: 8326591 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1040: Jpn J Cancer Res. 1993 Aug;84(8):871-8. Analysis of oncogenes and tumor suppressor genes in human breast cancer. Yamashita H, Kobayashi S, Iwase H, Itoh Y, Kuzushima T, Iwata H, Itoh K, Naito A, Yamashita T, Masaoka A, et al. Second Department of Surgery, Nagoya City University Medical School. Oncogenes (c-erbB-2, c-myc, and some genes linked to the 11q13 lesion), tumor suppressor genes (retinoblastoma gene, p53) and an antimetastatic gene (nm23/nucleoside diphosphate kinase) play important roles in breast cancer progression. Amplification of c-erbB-2, c-myc, and int-2, and expression of RB, p53(mutant), and NDP kinase were determined in 77 primary breast cancer specimens. nm23-H1 allelic loss was also studied. c-erbB-2 and c-myc amplification, loss of RB expression, p53(mutant) expression, and nm23-H1 allelic loss were also found in non-invasive carcinoma. int-2 amplification was significantly correlated with lymph node status (P = 0.02) and a significant association was found between p53(mutant) expression and tumor size (P = 0.04). c-erbB-2 amplification was strongly associated with disease-free and overall survival in multivariate analysis (P = 0.002). All of the c-erbB-2 amplified cases and all but one of the int-2 amplified cases in node-positive patients had relapsed within 2 years post resection. The cancer cells may acquire new proliferative pathways sequentially as a result of multiple genetic alterations which enable them to bypass the estrogen-dependent proliferation. PMID: 8104920 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1041: Acta Pathol Jpn. 1993 Jul-Aug;43(7-8):413-22. c-myc, ras p21 and p53 expression in pleomorphic adenoma and its malignant form of the human salivary glands. Deguchi H, Hamano H, Hayashi Y. Department of Oral Pathology, Tokushima University School of Dentistry, Japan. Using an immunohistochemical study and an immunoblot analysis, the expression of cellular oncogenes of the human salivary glands such as c-myc, ras p21, and p53 tumor-suppressor gene in pleomorphic adenomas and its malignant form, carcinoma in pleomorphic adenomas was examined to evaluate a differential biological significance, in comparison with that in normal salivary gland tissues. Immunohistochemically, the c-myc product was detected in 42% of the pleomorphic adenomas and in 56% of the carcinomas in pleomorphic adenoma. The ras p21 expression was observed in 24% of pleomorphic adenomas, and in 50% of carcinomas in pleomorphic adenoma. The p53 protein was detected in 18% of the pleomorphic adenomas and in 67% of the carcinomas in pleomorphic adenoma. Although there was no significant difference between the benign and malignant forms for the expression of c-myc, a statistical significance in ras p21 and p53 expression was found between the pleomorphic adenoma and its malignant form (P < 0.05) and P < 0.001, respectively). An immunoblotting assay clearly demonstrated the expression of c-myc and p53 gene products in both the benign and malignant forms of the pleomorphic adenoma, and that of ras p21 in the malignant form. These results indicate that activation of c-myc and ras p21 proto-oncogenes and the involvement of p53 mutation may play important roles in the malignant transformation of salivary gland pleomorphic adenoma. PMID: 8396843 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1042: Leukemia. 1993 Jul;7(7):954-62. Expression and DNA rearrangement of proto-oncogenes in Cas-Br-E-induced non-T-, non-B-cell leukemias. Bergeron D, Houde J, Poliquin L, Barbeau B, Rassart E. Department of Biological Sciences, University of Quebec, Montreal, Canada. The Cas-Br-E murine leukemia virus is a non-defective retrovirus that induces non-T-, non-B-cell leukemias in susceptible NIH/Swiss mice. A collection of tumors was examined for genomic DNA structure and RNA expression of known or putative proto-oncogenes and one tumor-suppressor gene, with the aim of identifying genes involved in Cas-Br-E-induced non-T-, non-B-cell leukemogenesis. Fli-1, p53, and Evi-1 were found to be rearranged in 72%, 23%, and 18% of the tumors, respectively, whereas no DNA alteration were detected for c-myc, c-myb, Pim-1, Evi-2, and EpoR genes. Evi-1 rearrangements are rarely associated with p53 or Fli-1 alterations. However, rearrangements of these last two genes are very often associated within the same tumor. Moreover, patterns of coordinated expression of critical cell growth-regulating genes are consistently associated with specific tumor types. These data suggest that Cas-Br-E can induce two types of hematopoietic neoplasias by different mechanisms. PMID: 8391616 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1043: Jpn J Cancer Res. 1993 Jul;84(7):818-20. Unusual interactions of adenovirus 5 and 12 E1B proteins with p53. van der Eb AJ. Publication Types: Letter PMID: 8370657 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1044: Blood. 1993 Jul 1;82(1):15-21. Control of programmed cell death in normal and leukemic cells: new implications for therapy. Sachs L, Lotem J. Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel. Programmed cell death (apoptosis) is a normal process by which cells are eliminated during normal embryonic development and in adult life. Disruption of this normal process resulting in illegitimate cell survival can cause developmental abnormalities and facilitate cancer development. Normal cells require certain viability factors and undergo programmed cell death when these factors are withdrawn. The viability factors are required throughout the differentiation process from immature to mature cells. Although many viability factors are also growth factors, viability and growth are separately regulated. Viability factors can have clinical value in decreasing the loss of normal cells including the loss that occurs after irradiation, exposure to other cytotoxic agents or virus infection including AIDS. There is no evidence that occurs after irradiation, exposure to other cytotoxic agents or virus infection including AIDS. There is no evidence that cancer cells are immortal. Programmed cell death can be induced in leukemic cells by removal of viability factors, by cytotoxic therapeutic agents, or by the tumor-suppressor gene wild-type p53. All these forms of induction of programmed cell death in leukemic cells can be suppressed by the same viability factors that suppress programmed cell death in normal cells. A tumor-promoting phorbol ester can also suppress this death program. The induction of programmed cell death can be enhanced by deregulated expression of the gene c-myc and suppressed by the gene bcl-2. Mutant p53 and bcl-2 suppress the enhancing effect on cell death of deregulated c-myc, and thus allow induction of cell proliferation and inhibition of differentiation which are other functions of deregulated c-myc. The suppression of cell death by mutant p53 and bcl-2 increases the probability of developing cancer. The suppression of programmed cell death in cancer cells by viability factors suggests that decreasing the level of these factors may increase the effectiveness of cytotoxic cancer therapy. Treatments that downregulate the expression or activity of mutant p53 and bcl-2 in cancer cells should also be useful for therapy. Publication Types: Review PMID: 8324219 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1045: Oncogene. 1993 Jun;8(6):1495-500. Wild-type p53 induces apoptosis in a Burkitt lymphoma (BL) line that carries mutant p53. Ramqvist T, Magnusson KP, Wang Y, Szekely L, Klein G, Wiman KG. Department of Tumor Biology, Karolinska Institute, Stockholm, Sweden. All Burkitt lymphoma (BL) biopsies and cell lines carry a c-myc/Ig translocation. The resulting constitutive activation of c-myc is regarded as an essential factor for the progressive growth of the tumor cells. At least 60% of BL cell lines carry a mutated p53 gene as well. It has been shown that the growth of mutant p53 carrying tumor cells could be inhibited by the introduction of wild-type p53. In order to examine whether this also applies to the presumably 'myc-driven' BL cell, we have transfected the Epstein-Barr virus (EBV) negative BL41 cell line with a temperature sensitive p53 mutant (p53-Val135) that expresses p53 with a largely mutant conformation at 37.5 degrees C and mostly wild-type conformation at 32 degrees C. At 37.5 degrees C, the p53-Val135 transfected cells behaved like the parental or neo transfected control cells. However, expression of exogenous wild-type p53 at 32 degrees C resulted in a rapid reduction of the number of viable cells while the parental and neo control cells remained unaffected. Cell death was due to apoptosis as shown by chromatin and nuclear condensation and specific DNA fragmentation. The first signs of apoptosis were evident after 10 h at 32 degrees C and after 3 days 90-100% of the cells had undergone apoptosis. These findings indicate an incompatibility between expression of wild-type p53 and progressive growth of BL cells if their neoplastic development has included a p53 mutation. The question whether apoptosis was induced in by the wild-type protein per se or by the contradictory signals of a constitutively activated c-myc and wild-type p53 needs further investigation. PMID: 8502475 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1046: J Gen Virol. 1993 Jun;74 ( Pt 6):955-63. Characterization of human keratinocytes transformed by high risk human papillomavirus types 16 or 18 and herpes simplex virus type 2. Dhanwada KR, Garrett L, Smith P, Thompson KD, Doster A, Jones C. Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, Illinois 60153. Recent reports implicate two DNA tumour viruses, herpes simplex virus type 2 (HSV-2) and human papillomavirus types 16 or 18 (HPV-16 and -18), in the pathogenesis of cervical cancer. Previous studies have indicated that primary human fibroblasts transfected with HPV-16 and HSV-2 morphological transforming region III (mtr III) are more aneuploid than fibroblasts immortalized with HPV-16 and that HSV-2 DNA sequences are retained in transformed cells. Since HSV-2 and HPV typically infect cells of epithelial origin, the interactions of these viruses with respect to morphological transformation were examined in human keratinocytes. HPV-16- or HPV-18-immortalized keratinocytes (FEPL and FEA cells, respectively) were transfected with fragments derived from HSV-2 mtr III. When compared to their normal counterparts, FEPL cells and FEA cells transfected with mtr III fragments grew to higher saturation densities and were morphologically transformed. FEPL cells transformed by HSV-2 were capable of growth in soft agar and, when injected into nu/nu mice, lesions developed at the site of injection. Histological examination of the lesions revealed a benign mass which was composed of squamous epithelial cells that were producing keratin. In contrast, immortalized keratinocytes (FEPL or FEA) or FEA cells transfected with HSV-2 did not produce these lesions. These observations suggest that sequences within mtr III can alter the growth properties of human keratinocytes immortalized by HPV-16 or HPV-18. PMID: 8389810 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1047: Cell Growth Differ. 1993 Jun;4(6):467-73. Reconstitution of wild-type p53 expression triggers apoptosis in a p53-negative v-myc retrovirus-induced T-cell lymphoma line. Wang Y, Ramqvist T, Szekely L, Axelson H, Klein G, Wiman KG. Department of Tumor Biology, Karolinska Institute, Stockholm, Sweden. Inactivation or mutation of the p53 tumor suppressor gene has been observed in a wide variety of human and murine tumors. We have found that a v-myc retrovirus (J3)-induced T-cell lymphoma line (J3D) has lost one of its p53 alleles, whereas the other has become inactivated due to the insertion of a Moloney murine leukemia provirus in intron 4 with an opposite transcriptional orientation. No p53 protein could be detected by immunoprecipitation with monoclonal anti-p53 antibodies. We have transfected this line with the temperature-sensitive murine Val135 construct that is expressed as mutant p53 at 37 degrees C and largely wild-type p53 at 32 degrees C. There was no difference in the number of viable cells among the p53 transfectants, the parental cells, and neomycin vector-transfected control cells at 37 degrees C. Following a temperature shift to 32 degrees C, the p53 transfectants rapidly lost viability, and 95-100% of the cells were dead by 3 days, whereas the control cells remained unaffected. Examination of DNA isolated from p53-transfected cells grown at 32 degrees C revealed nucleosomal fragmentation, indicating cell death by apoptosis. It is suggested that apoptosis is triggered by contradictory signaling. Constitutively expressed v-myc can stimulate cell proliferation, whereas expression of wild-type p53 in cells that have lost endogenous p53 expression in the course of their neoplastic development may suppress growth. PMID: 8373731 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1048: Cancer. 1993 May 15;71(10 Suppl):3320-4. Pediatric molecular oncology. Past as prologue to the future. Knudson AG Jr. Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111. The great successes in the treatment of childhood cancers have been followed in recent years with a new understanding of the molecular genetic abnormalities that underlie their origin. For some cancers these genetic changes are in oncogenes; in others, they are in antioncogenes, or tumor suppressor genes. Initiating aberrations in the former are associated characteristically with chromosomal translocations, the analysis of which should soon lead to the identification of oncogenes other than those in the myc family. Several tumor suppressor genes of importance in the childhood cancers have been cloned and others should soon follow. It is reasonable to expect that during the current decade molecular understanding of the genetic defects in the major pediatric cancers will be achieved. The knowledge gained through these studies, past and future, may provide new approaches to prevention and treatment and lead to additional progress. PMID: 8490875 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1049: Oncogene. 1993 May;8(5):1183-93. Wild-type but not mutant p53 can repress transcription initiation in vitro by interfering with the binding of basal transcription factors to the TATA motif. Ragimov N, Krauskopf A, Navot N, Rotter V, Oren M, Aloni Y. Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel. It has previously been shown that excess wild type (wt) p53 can repress the transcriptional activity of a variety of promoters in intact cells. To determine whether this transcriptional repression represented a direct effect of p53, wt and mutant p53 were prepared from E. coli-produced p53 and from insect cells infected with a recombinant baculovirus. When added into an in vitro transcription system, wt p53, but not mutant p53 reduced markedly transcription from the c-myc promoter, as well as from an array of other promoters, with the exception of an MHC class I gene promoter. The presence of wt p53 seemed to affect specifically the formation of the transcription preinitiation complex because preformed initiation complexes were completely refractory to wt p53, as was also the process of transcript elongation. Wild-type but not mutant p53 interfered with the stable binding of TBP and TFIIA to the TATA motif, although both wt and mutant p53 could associate in vitro with purified TBP. We propose that upon binding to TBP, wt but not mutant p53 specifically blocks the ability of TBP to engage in interactions required for efficient transcriptional initiation. This may account, at least in part, for the ability of excess wt p53 to inhibit cell proliferation and to interfere with neoplastic processes. PMID: 8479742 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1050: J Natl Cancer Inst. 1993 Apr 7;85(7):570-4. Heat shock protein hsp70 in patients with axillary lymph node-negative breast cancer: prognostic implications. Ciocca DR, Clark GM, Tandon AK, Fuqua SA, Welch WJ, McGuire WL. Department of Medicine, University of Texas Health Science Center, San Antonio 78284-7884. BACKGROUND: Cell synthesis of heat shock (stress-response) proteins is increased by a variety of environmental and pathophysiological stressful conditions. The 70-kd heat shock protein (hsp70) is thought to be involved in protein-protein interactions including those of the protein products of the human c-myc oncogene and the p53 (also known as TP53) tumor suppressor gene. PURPOSE: The purpose of this study was to investigate whether elevated hsp70 expression may be an indicator of biological stress experienced by a breast cancer and may, therefore, predict disease outcome. METHODS: Levels of hsp70 were determined by Western blot analysis in primary breast tumors from patients with negative axillary lymph nodes. We performed exploratory data analyses on a set of 162 primary breast cancers and constructed prognostic indexes of hsp70 expression levels. The optimal cutpoint for hsp70 expression was considered to be the value yielding the greatest separation for disease-free survival for the resulting two groups of patients. That cutpoint was then validated in a set of 345 tumors by univariate and multivariate analyses. Data were analyzed for overall survival, disease-free survival, tumor size, and patient age, as well as estrogen receptor and progesterone receptor status, ploidy (DNA content), and percentage of cells in S phase as determined by flow cytometry. RESULTS: Expression of hsp70 emerged as a useful prognostic factor, both in univariate and in multivariate analyses. Patients whose tumors had high expression of hsp70 had significantly shorter disease-free survival (P = .006). The other statistically significant factors were S-phase fraction (P = .008) and tumor size (P = .01). For patients who received adjuvant therapy, hsp70 was the only independent predictor of disease recurrence (P = .05). For those with tumors 1-3 cm in diameter, hsp70 (P = .008) and S-phase fraction (P = .02) were statistically significant predictors of recurrence. CONCLUSIONS: Measurement of hsp70 expression in primary tumors from patients with node-negative breast cancer may be useful in identifying patients at high risk for disease recurrence and thus may affect decisions regarding treatment after surgery. IMPLICATIONS: Future studies should be performed to determine if detection of hsp70 by immunohistochemistry can be used to predict clinical outcome and to better understand the relationships between hsp70 and the effects of various treatment modalities. PMID: 8455204 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1051: Virology. 1993 Apr;193(2):579-91. Overexpression of wild-type p53 and c-Myc in human fetal cells transformed with adenovirus early region 1. Grand RJ, Lecane PS, Roberts S, Grant ML, Lane DP, Young LS, Dawson CW, Gallimore PH. Department of Cancer Studies, Medical School, University of Birmingham, United Kingdom. The expression of p53 in a large panel of adenovirus (Ad) 2/5- and 12-transformed human, rat, and mouse cells has been examined. In all cases, in the absence of the larger Ad E1B protein, the level of p53 is very low. In human and rat cells when the Ad 12 E1B 54K polypeptide is expressed, p53 is much more abundant, although this is not the case in Ad 12 E1-transformed mouse cells. We conclude that expression of p53 is determined by virus serotype, host cell type, and viral proteins expressed. p53 in Ad 12 E1-transformed human cells is wild type but has an extended half-life. Stabilization is not through protein-protein interaction with the Ad E1B protein. The level of expression of c-Myc is also elevated in Ad-transformed human cells but this does not correlate with the presence of the E1B protein or with p53. However, Northern blot analysis indicates a direct correlation between mRNA and protein levels. We conclude that c-Myc is regulated at the transcriptional level, whereas p53 is regulated at the post-translational level in adenovirus transformants. PMID: 8460477 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1052: Eur J Cancer B Oral Oncol. 1993 Apr;29B(2):107-12. Molecular lesions in human oral cancer: the Indian scene. Saranath D, Bhoite LT, Deo MG. Cell and Developmental Pathology Division, Cancer Research Institute, Bombay, India. Carcinogenesis is a multi-step process including aberrant expression of two interacting classes of genes--oncogenes and tumour suppressor genes. With recent technological advances, it is feasible to identify the various molecular lesions underlying the different stages of neoplasia. Squamous cell carcinomas of the head and neck, although representing 2-4% of the malignancies in the West, comprise a large fraction (40%) of total cancers in India, posing a major health problem. Further, epidemiological and experimental evidence unequivocally confirms a causal association between tobacco chewing habit, highly prevalent in India, and oral cancers. Thus, the oral cancers offer an excellent in vivo system for the study of the environmental tobacco-carcinogen induced molecular alterations in the malignancy, and associated premalignant lesions such as leukoplakia. With a view to elucidating the molecular lesions involving oncogenes in oral carcinogenesis, we have investigated myc/ras/EGF-R activation by amplification, point mutation, gene rearrangement and allelic losses. Further, a functionally activated potent transforming gene was detected in a NIH3T3 transfection/tumorigenicity assay, unrelated to myc/ras/EGF-R. Studies on the involvement of p53 gene in oral cancer, indicates p53 allelic loss as an event observed in leukoplakia and tumour tissues. Advanced oral cancer stages demonstrate cumulative molecular aberrations, with greater than 95% samples showing oncogene involvement, thus indicating a multi-step process of oral carcinogenesis. The review presents a comparative picture of the oral malignancies seen in Western countries and India, significance of molecular lesions and future perspectives of oncogenes and tumour suppressor gene involvement in oral cancer. Publication Types: Review Review, Tutorial PMID: 7910088 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1053: Blood Rev. 1993 Mar;7(1):63-73. The role of apoptosis (programmed cell death) in haemopoiesis and the immune system. Allen PD, Bustin SA, Newland AC. Department of Haematology, Royal London Hospital, Whitechapel, UK. Apoptosis, or programmed cell death, is a series of controlled sequential events resulting in the demise of cells without invoking an inflammatory response. It is a naturally occurring process which maintains a cellular balance during both animal development and in the mature adult. Although first described 20 years ago, there is now renewed interest in this phenomenon, particularly in the light of our greater understanding of cellular signalling pathways and their genetic control. This is especially pertinent to haemopoiesis and the overall maintenance of a functional immune system. This review broadly covers the biochemical events of apoptosis and the recognition of apoptotic cells by phagocytes. Reference is made to the selective development of T- and B-cells and to the control of inflammation. Molecular events in apoptosis are also discussed with special reference to aberrant bcl-2 gene expression in follicular B-cell lymphoma and the role of other death genes in the control of apoptosis. PMID: 8467234 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1054: Carcinogenesis. 1993 Mar;14(3):503-10. p53 mutations in hepatocellular carcinomas induced by a choline-devoid diet in male Fischer 344 rats. Smith ML, Yeleswarapu L, Scalamogna P, Locker J, Lombardi B. Department of Pathology, School of Medicine, University of Pittsburgh, PA 15261. Analyses were performed on livers and hepatocellular carcinomas from male Fischer 344 rats fed a choline-devoid diet, to assess whether they carried alterations of the p53 tumor suppressor gene. The analyses consisted of immunoperoxidase staining of tissue sections with monoclonal antibodies to p53, Western blotting and cDNA sequencing. Immunostaining revealed the presence of mutant p53 proteins in 22/27 tumors analyzed and immunoblotting in 18/20. Immunochemical evidence was obtained that occurrence of the mutations precedes tumor development. cDNA sequencing was performed on 11 hepatocellular carcinomas that expressed mutant p53 gene proteins. Seven were found to contain point mutations within the 120-290 codon region of the gene, and one a microdeletion in the same region. No mutational hot spot was observed. It is concluded that mutations within the p53 gene, along with a c-myc gene amplification previously detected in these tumors, most likely contribute to the neoplastic transformation of liver cells in this nutritional model of hepatocarcinogenesis. The results are discussed also in view of recent literature on the presence of p53 mutations in human hepatocellular carcinomas. PMID: 8453727 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1055: Mol Cell Biol. 1993 Mar;13(3):1415-23. p53-mediated cell death: relationship to cell cycle control. Yonish-Rouach E, Grunwald D, Wilder S, Kimchi A, May E, Lawrence JJ, May P, Oren M. Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel. M1 clone S6 myeloid leukemic cells do not express detectable p53 protein. When stably transfected with a temperature-sensitive mutant of p53, these cells undergo rapid cell death upon induction of wild-type (wt) p53 activity at the permissive temperature. This process has features of apoptosis. In a number of other cell systems, wt p53 activation has been shown to induce a growth arrest. Yet, wt 53 fails to induce a measurable growth arrest in M1 cells, and cell cycle progression proceeds while viability is being lost. There exists, however, a relationship between the cell cycle and p53-mediated death, and cells in G1 appear to be preferentially susceptible to the death-inducing activity of wt p53. In addition, p53-mediated M1 cell death can be inhibited by interleukin-6. The effect of the cytokine is specific to p53-mediated death, since apoptosis elicited by serum deprivation is refractory to interleukin-6. Our data imply that p53-mediated cell death is not dependent on the induction of a growth arrest but rather may result from mutually incompatible growth-regulatory signals. PMID: 8441387 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1056: Anticancer Res. 1993 Mar-Apr;13(2):491-5. Polyamine content and oncogene expression in hepatoma cells in culture during methionine deprivation and refeeding. Lafarge-Frayssinet C, Cassingena R, Frayssinet C, Estrade S, Havouis R, Moulinoux JP. Laboratory of Molecular genetics, UPR 42 CNRS, Institut de Recherches Scientifiques sur le Cancer, Villejuif, France. From an hepatocarcinoma cell line (LFCL.2A), unable to grow in a culture medium in which methionine was replaced by L-homocysteine, we had previously isolated revertant clones presenting a low growth rate, a loss of tumorigenicity and an inhibition of transcription of three oncogenes: c-Ki-ras, c-Ha-ras and c-myc. Here we showed that long-term deprivation of methionine led to a depletion of spermine, while putrescine and spermidine contents remained unchanged. When the revertant cells were shifted in a medium containing methionine, the oncogene transcription (except the p53 gene) started very rapidly in parallel with an increase in the putrescine content. By contrast, spermidine and spermine contents decreased during the first hours but were not significantly different from control values after numerous subcultures in methionine-containing medium. PMID: 8390803 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1057: Int J Cancer. 1993 Feb 20;53(4):672-9. Molecular and cellular heterogeneity of Wilms' tumor. Velasco S, D'Amico D, Schneider NR, Timmons C, Chappell E, Lee D, Nisen PD. Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235-9063. We developed a Wilms' tumor-cell culture system to investigate the molecular basis of nephrogenesis and oncogenesis. Several distinct fractions of cells were isolated and characterized from the same tumor specimen. The cells exhibited striking differences in morphology, immunocytochemical staining profiles and cytogenetics. One fraction contained cells with features of epithelium; other cell fractions resembled partially differentiated mesenchyme (blastema or stroma). While the Wilms' tumor-suppressor gene WT1 was not altered, loss of heterozygosity (LOH) and an insertion in intron I of the p53 tumor-suppressor gene occurred in the tumor and the cultured cell types. LOH for RB was detected only in the cultured cells. These findings are consistent with a model of tumor initiation in a pluripotent cell that is able to undergo subsequent differentiation along multiple different lines and which mimics normal nephrogenesis. PMID: 8094715 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1058: Nippon Rinsho. 1993 Feb;51(2):386-93. [Recent progress in molecular biology of chemically-induced hepatic carcinogenesis] [Article in Japanese] Ogawa K. Department of Pathology, Asahikawa Medical College. Chemically-induced hepatic carcinogenesis is a suitable model to investigate multistep process of carcinogenesis, because preneoplastic and neoplastic lesions develop in a sequential manner. The process is initiated by emergency of "genetically altered cells" or "initiated cells" which have a potential to progress to hepatocellular carcinomas. The cells can clonally expand under the effect of tumor promoters or carcinogens. Clonal expansion will increase the probability that a cell undergoes further genetic changes. By this stepwise manner, a cell may acquire neoplastic properties such as independence to growth factors, invasive growth, loss of antigenicity, metastatic capacity, etc. The author reviewed the recent advance in studies on oncogenes, tumor suppressor genes and growth factor genes concerning to rodent hepatic carcinogenesis. Publication Types: Review PMID: 8464152 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1059: Nucleic Acids Res. 1993 Jan 25;21(2):345-50. The helix-loop-helix containing transcription factor USF binds to and transactivates the promoter of the p53 tumor suppressor gene. Reisman D, Rotter V. Department of Biological Sciences, University of South Carolina, Columbia 29208. Expression of the wild-type p53 tumor suppressor gene has been found to play an important role in the regulation of cellular proliferation and differentiation. In addition, in many transformed cells and primary tumors, the gene has undergone allelic deletions and mutant forms of the p53 gene are expressed at elevated levels. In defining transcriptional regulatory regions of the p53 gene, we have previously shown that both the human and murine p53 promoters contain a conserved consensus recognition sequence for the basic-helix-loop-helix (bHLH) containing family of DNA-binding proteins. In the murine p53 promoter this element is required for full promoter activity and contains the sequence CACGTG, a sequence identical to the recognition site for the bHLH containing transcription factors c-Myc, USF and TFE3. Here we examine the ability of one of these factors, USF, to bind to the p53 promoter. By assaying the binding activity of in vitro translated USF as well as factors present in nuclear extracts, we conclude that the transcription factor USF binds in a site-specific manner to a CACGTG motif within the murine p53 promoter and represents the major DNA-binding activity observed in nuclear extracts. Elevated levels of USF, generated upon transfection of a vector expressing USF, lead to enhanced activity of the p53 promoter. These findings indicate that USF may play a central role in regulating p53 expression. PMID: 8441640 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1060: Int J Cancer. 1993 Jan 2;53(1):11-6. Loss of heterozygosity at chromosome 17p is associated with HER-2 amplification and lack of nodal involvement in breast cancer. Knyazev PG, Imyanitov EN, Chernitsa OI, Nikiforova IF. Laboratory of Molecular Genetics, N.N. Petrov Research Institute of Oncology, St-Petersburg, Russia. Sixty DNA samples from breast carcinoma (BC) patients were analyzed by Southern blot to examine certain oncogene and anti-oncogene alterations. Amplification of the HER-2 oncogene was detected in 15 tumours (25%), c-myc in 2 (3%) only and HER-1 in none. Distribution of Hras-1 oncogene alleles in BC did not significantly differ from that seen in healthy donors. Not a single case of RB-1 anti-oncogene alteration and only one of p53 suppressor gene abnormality was found when appropriate cDNA copies were used as probes. With the use of DNA polymorphic markers, loss of heterozygosity (LOH) was revealed at chromosome 17p (probe YNZ-22) in 18 of 39 (46%) informative cases, at 17q (probe THH-59) in 10 of 34 (29%) and at 11p (probe Hras-1) in 8 of 30 (27%). The only significant correlation between these genetic alterations and the clinical characteristics of the tumours studied was the association of LOH at 17p with node-negative BC (p < 0.02). Also, the tendency for correlation (p < 0.2) between HER-2 amplification and loss of 17p sequences was revealed: 7 of 10 amplification-positive, but only 11 of 29 amplification-negative BC possessed LOH of YNZ-22 locus. PMID: 8416194 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1061: Fukuoka Igaku Zasshi. 1993 Jan;84(1):25-35. [Analysis of molecular mechanism in colorectal tumorigenesis] [Article in Japanese] Shirasawa S. Department of Genetics, Kyushu University, Fukuoka. Genetic alterations of Ki-ras gene, p53 gene, and DCC gene were analyzed in human colon cancer cell lines (HCCLs). On the basis of these analyses, a HCCL (HCT116)-human chromosome 18 hybrids, and targeted cell lines that were disrupted at the activated Ki-ras gene in HCCLs (HCT116 and DLD-1), were established. Tumorigenicity and expression of c-myc gene were investigated in these cell lines, respectively. 1. Point mutations of Ki-ras gene, p53 gene, and insertion mutations of DCC gene were detected in 10 out of 18 HCCLs, 8 out of 15 HCCLs, and 3 out of 16 HCCLs, respectively. 2. HCT116-chromosome 18 hybrids were morphologically similar to the parental line, and were not suppressed for tumorigenicity in vitro, but they produced slowly growing tumors in nude mice compared with the growth of the parental line. 3. The targeted cell lines that were disrupted at the activated Ki-ras gene were morphologically altered and lost neoplastic phenotypes, including tumorigenicity in nude mice and anchorage-independent growth. Furthermore, expression of c-myc gene in these clones was much reduced compared with findings in the parental line, regardless of their growth rates. PMID: 8458595 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1062: Cell Growth Differ. 1993 Jan;4(1):41-7. Regulation by bcl-2, c-myc, and p53 of susceptibility to induction of apoptosis by heat shock and cancer chemotherapy compounds in differentiation-competent and -defective myeloid leukemic cells. Lotem J, Sachs L. Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel. Myeloid leukemias that differ in their competence for induction of differentiation were analyzed for expression of bcl-2 and c-myc and for their sensitivity to induction of apoptosis by heat shock and cancer chemotherapy compounds. The M1 leukemia expressed a high level of bcl-2 and showed a much lower susceptibility to induction of apoptosis by heat shock, Adriamycin, 1-beta-D-arabinofuranosylcytosine, methotrexate, and cycloheximide, compared to five other leukemias which expressed a low level of bcl-2. There was no association between susceptibility to induction of apoptosis and competence for induction of differentiation. The difference in susceptibility to methotrexate, which is not regulated by the multidrug resistance (MDR) genes, and treatment with verapamil, which blocks MDR activity, have indicated that the higher resistance of the M1 leukemia to these agents was not due to MDR activity. The results indicate that the level of regulated bcl-2 expression in these myeloid leukemias was associated with cell susceptibility to induction of apoptosis by different apoptosis-inducing agents. Screening for expression of bcl-2 may thus be useful to characterize leukemias regarding susceptibility to induction of apoptosis by different agents. The level of regulated c-myc expressed in these leukemias was not associated with susceptibility to induction of apoptosis. Transfection with a deregulated mutant p53 into the M1 leukemia did not change susceptibility to apoptosis induction, but transfection with deregulated c-myc increased susceptibility to apoptosis.(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 8424905 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1063: Lab Invest. 1993 Jan;68(1):26-32. Squamous metaplasia expression of proto-oncogenes and P 53 in lung cancer patients. Klein N, Vignaud JM, Sadmi M, Plenat F, Borelly J, Duprez A, Martinet Y, Martinet N. INSERM U 14, Service d'Anatomo-pathologie A and Federation Medicale et Chirurgicale de Pneumologie du Centre Hospitalier Regional de Nancy, France. BACKGROUND: The question of whether bronchial squamous metaplasia is a true preneoplasia is important and demonstrated in animal for several carcinogens. We have now approached this problem in humans and in vivo. EXPERIMENTAL DESIGN: Squamous metaplasia in the close vicinity of surgically resected lung tumors were evaluated for their mitotic index and screened for proto-oncogenes and P 53 protein expression by immunohistochemistry and/or in situ hybridization. RESULTS: Among 16 patients, 4 had squamous metaplasia positive for either myc messages and/or for P 53 protein accumulation. In the same patients (3/4), the autologous bronchial tumors were also positive for the same markers. Squamous metaplasia positivity was observed essentially in patients with advanced diseases and only in squamous cell carcinomas. In addition, when evaluated with 5 iodo-2'-deoxyuridine systemic infusion, all patients presented hyperproliferative basal squamous metaplasic cells. CONCLUSIONS: These results are reminiscent of the typical preneoplastic changes observed in familial colic adenomatosis, where genetic changes accumulate in hyperproliferative cells. They also suggest that bronchial squamous metaplasia could be an authentic preneoplasia in, at least, squamous cell carcinomas. PMID: 8423673 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1064: Mol Cell Biol. 1993 Jan;13(1):301-6. The mdm-2 oncogene can overcome wild-type p53 suppression of transformed cell growth. Finlay CA. Department of Molecular Biology, Princeton University, New Jersey 08544-1014. Expression of a p53-associated protein, Mdm-2 (murine double minute-2), can inhibit p53-mediated transactivation. In this study, overexpression of the Mdm-2 protein was found to result in the immortalization of primary rat embryo fibroblasts (REFs) and, in conjunction with an activated ras gene, in the transformation of REFs. The effect of wild-type p53 on the transforming properties of mdm-2 was determined by transfecting REFs with ras, mdm-2, and normal p53 genes. Transfection with ras plus mdm-2 plus wild-type p53 resulted in a 50% reduction in the number of transformed foci (relative to the level for ras plus mdm-2); however, more than half (9 of 17) of the cell lines derived from these foci expressed low levels of a murine p53 protein with the characteristics of a wild-type p53. These results are in contrast to previous studies which demonstrated that even minimal levels of wild-type p53 are not tolerated in cells transformed by ras plus myc, E1A, or mutant p53. The mdm-2 oncogene can overcome the previously demonstrated growth-suppressive properties of p53. PMID: 8417333 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1065: Cancer Detect Prev. 1993;17(2):267-77. Molecular implications of recurrent cytogenetic alterations in human small cell lung cancer. Testa JR, Graziano SL. Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, PA. This article describes cytogenetic findings in human small cell lung cancer (SCLC). Included is a summary of analyses performed by the authors on 17 tumors, each of which displayed numerous chromosomal alterations. Many of the recurrent changes involve losses at the locations of tumor suppressor genes, whose loss and/or inactivation may play a crucial role in tumorigenesis. Deletions of the short arm of chromosome 3 (particularly 3p21-25) were found in every case, providing additional evidence in support of the notion that this region harbors a tumor suppressor gene(s) critical in the pathogenesis of SCLC. Cytogenetic losses of 5q21, 13q14, and 17p13 (sites of the APC, RB1, and TP53 suppressor loci, respectively) also are common in SCLC. Double minutes are found in a minority of these tumors and are associated with oncogene amplification. The genetic complexity in SCLC underscores the need for greater preventive measures and early detection. PMID: 8402711 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1066: Blood. 1993 Jan 1;81(1):166-76. Multiple genetic lesions in acquired immunodeficiency syndrome-related non-Hodgkin's lymphoma. Ballerini P, Gaidano G, Gong JZ, Tassi V, Saglio G, Knowles DM, Dalla-Favera R. Department of Pathology, College of Physicians & Surgeons, Columbia University, New York, NY 10032. Non-Hodgkin's lymphoma (NHL) develops in about 5% to 10% of acquired immunodeficiency syndrome (AIDS) patients. The vast majority of AIDS-NHL are clinically aggressive B-cell NHL that are histologically classified as small noncleaved cell lymphoma (SNCCL), large cell immunoblastic plasmacytoid lymphoma (LC-IBPL), and large noncleaved cell lymphoma (LNCCL). In an attempt to understand the molecular pathogenesis of these tumors, we have investigated the involvement of dominantly acting oncogenes (c-myc, N-, K-, H-Ras), tumor suppressor genes (p53, RB1), and Epstein-Barr virus (EBV) infection in 27 AIDS-NHL samples (16 SNCCL, 5 LC-IBP, and 6 LNCCL). The following lesions were detected in AIDS-NHL: EBV infection (10/24; 41.6%), c-myc rearrangement (19/24; 79.1%), Ras mutation (4/27; 14.8%), and p53 loss/mutation (10/27; 37.0%). These lesions are not uniformly distributed, but, rather, cluster with specific types of AIDS-NHL: EBV infection is preferentially associated with LC-IBPL (4/4; 100%), while it is present in only a fraction of SNCCL (5/16; 31.2%) and LNCCL (1/4; 25%); c-myc oncogene activation clusters with SNCCL (16/16; 100%), whereas it is less frequent in LC-IBPL (1/4; 25%) and LNCCL (2/4; 50%); p53 inactivation is restricted to SNCCL (10/16; 62.5%) and consistently associated with c-myc activation. These data show that AIDS-NHL are associated with multiple genetic lesions that involve both proto-oncogenes and tumor suppressor genes and may accumulate in the relatively short period of time (4 to 6 years) between human immunodeficiency virus infection and AIDS-NHL development. These genetic lesions differ in the various AIDS-NHL subtypes, suggesting the involvement of distinct molecular pathway. PMID: 8380252 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1067: Mol Carcinog. 1993;8(4):306-11. Correlation of p53 mutations with epidermal growth factor receptor overexpression and absence of mdm2 amplification in human esophageal carcinomas. Esteve A, Lehman T, Jiang W, Weinstein IB, Harris CC, Ruol A, Peracchia A, Montesano R, Hollstein M. International Agency for Research on Cancer, Lyon, France. Esophageal carcinomas from 24 patients, most of whom were smokers and consumed alcoholic beverages daily, were analyzed for mutations in exons 5-8 of the p53 tumor suppressor gene. Mutations were identified by polymerase chain reaction amplification and direct sequencing in 12 of 24 (50%) of the samples; almost half of the mutations were at A:T base pairs. Nuclear accumulation of p53 protein, determined by immunohistochemistry with the CM-1 polyclonal antibody, was observed in all cases in which a missense mutation in the p53 gene was detected. None of the 24 carcinomas had amplification of the mdm2 gene, an alternate pathway to p53 loss of function. Alterations involving three other cancer-related genes associated with human esophageal carcinogenesis, c-erbB-1/epidermal growth factor receptor (EGFR), c-myc, and retinoblastoma (Rb), were examined by Southern blot or immunohistochemical analysis in the same sample set to explore the possibility of a link between oncogene activation and loss of tumor suppressor function. While no associations were observed between amplification of the c-myc or EGFR genes and p53 abnormalities, a significant correlation (P < 0.01) was seen between the presence of p53 mutation and EGFR overexpression. Absence of Rb protein, measured immunohistochemically, was observed in four tumors, none of which had aberrations of the p53 gene. PMID: 8280379 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1068: Leuk Lymphoma. 1993;11 Suppl 1:47-50. CML: mechanisms of disease initiation and progression. Wetzler M, Talpaz M, Estrov Z, Kurzrock R. Department of Clinical Investigation, University of Texas, M.D. Anderson Cancer Center, Houston 77030. Chronic myelogenous leukemia (CML) is a hematological stem cell disorder characterized by excessive proliferation of the myeloid lineage. It has a progressive course typified by the transition from the chronic phase to the accelerated phase and on to blast crisis. The hallmark of CML is the translocation between chromosomes 9 and 22 that results in the chimeric BCR-ABL gene encoding p210BCR-ABL. The oncogenic potential of this protein has been validated, and it is believed that it contributes in a critical way to the initiation of CML. However, the secondary genetic forces responsible for the transition from the chronic state to the fully blastic stage are not clear. Evidence for chromosomal instability includes the clonal evolution which characterizes advanced CML. In regard to specific genetic aberrations, sporadic reports have shown alterations in H-RAS, c-MYC, retinoblastoma, and P53 genes, as well as production of p190BCR-ABL during the progression of CML. In addition, we have recently found evidence for excessive interleukin-1 beta production, acting in an autocrine and/or paracrine manner, in the more advanced stages of the disease. Taken together, current data suggest that multiple molecular pathways lead to disease progression, and that distinct subsets of genetic alterations exist in blast crisis patients. Publication Types: Review Review, Tutorial PMID: 8251916 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1069: Arch Dermatol Res. 1993;285(6):334-40. In situ hybridization analysis of cytokine, proto-oncogene and tumour suppressor gene expression in psoriasis. Schmid P, Cox D, McMaster GK, Itin P. CIBA-GEIGY Ltd., Pharma Division, Basel, Switzerland. The purpose of this study was to investigate and to compare, by in situ hybridization, gene expression of IL-1 beta, IL-8, TGF-beta 1, TGF-beta 2, TGF-beta 3, TGF-alpha, p53 and c-myc in lesions and in non-involved skin of patients with psoriasis. All lesional skin biopsies showed overexpression of IL-1 beta, IL-8 TGF-alpha mRNAs. IL-1 beta hybridization signals were strong in a small number of cells localized predominantly in the dermal papillae and in the suprapapillary epidermis. Overexpression of TGF-alpha was observed in all suprabasal keratinocytes, whereas strongly elevated IL-8 mRNA expression was found to be restricted to clusters of suprabasal keratinocytes. TGF-beta 3, p53 and c-myc transcripts were clearly detected in the epidermis of all biopsies, although expression levels were comparable in lesional and non-lesional skin. PMID: 8215583 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1070: J Cancer Res Clin Oncol. 1993;119(12):737-44. Comparative analysis of p53 and c-myc expression and cell proliferation in human hepatocellular carcinomas--an enhanced immunohistochemical approach. Saegusa M, Takano Y, Kishimoto H, Wakabayashi G, Nohga K, Okudaira M. Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan. Expression of p53 and c-myc was investigated and compared with cell proliferative activity in a series of 40 hepatocellular carcinomas (HCC), by means of enhanced immunohistochemistry. p53 expression was demonstrated in 5 out of 40 HCC (12.5%) with the incidence increasing in 5 out of 40 HCC (12.5%) with the incidence increasing in proportion to the histological grading of malignancy: thus, 0% of well-differentiated, 6.9% of moderately differentiated and 33.3% of poorly differentiated lesions were positive. The proliferating-cell nuclear antigen (PCNA) labeling index also showed a statistically significant increase with this grading. Distribution patterns of PCNA-positive cell were divided into four types: scatter, marginal, mosaic and diffuse. Four HCC cases, predominantly of the poorly differentiated type, exhibited the diffuse pattern. Generally, p53 overexpression corresponded well with PCNA positivity. In contrast, there was no correlation between c-myc overexpression, found in 19 out of 40 HCC (47.5%), and histological grading of HCC or PCNA labeling index. The distribution pattern of c-myc-positive HCC cells was also different from that of PCNA and p53. Our results suggest that p53 overexpression closely relates to proliferation of HCC cells. Furthermore, there may be a consistent difference in regulatory mechanisms between p53 and c-myc expression in multistep hepatocarcinogenesis. PMID: 8104947 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1071: Oncol Res. 1993;5(10-11):397-408. DNA damage, gene expression, growth arrest and cell death. Gewirtz DA. Department of Medicine, Medical College of Virginia, Richmond 23298. The sequence of biochemical and molecular events that mediate growth arrest and cell death in tumor cells exposed to agents that induce DNA damage is poorly defined. This commentary exploits the recent explosion of information regarding oncogenes, tumor suppressor genes, and cell-cycle regulatory genes to develop a model for growth arrest/cell death. The model focuses on changes in the expression of these genes, in the level and phosphorylation of their protein products, and in the interaction(s) between these proteins. It is recognized that such a model is, of necessity, incomplete, since new gene functions associated with the cellular response to DNA damage will continuously be uncovered; in addition, the proposed sequence of events will likely require modification as the relationships between the functions of the discrete gene products are clarified. Nevertheless, it is hoped that this commentary will provide a conceptual framework within which to fit currently available information as well as future findings relating to the expression and function of DNA-damage-responsive genes, and that the sections of the model that are incomplete will provide a springboard for the development of research approaches designed to answer specific questions regarding the nature of the cellular response to DNA damage. Publication Types: Review PMID: 8054700 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1072: Monogr Pathol. 1993;(36):134-44. Molecular pathology of lung cancer and its clinical relevance. Cagle PT. Department of Pathology, Baylor College of Medicine, Houston, Texas. Evidence indicates that several molecular genetic markers involved in the initiation and progression of lung cancer are useful in predicting prognosis in early stage lung cancer, thus allowing selection of subsets of patients for additional therapy and are likely to be useful in the diagnosis of malignancy in equivocal biopsies and cytology specimens. In the future, these markers may also prove to be useful in the early detection of lung cancer and in predicting response to specific therapies. Most of these markers can already be assessed by routine immunohistochemical techniques on paraffin-embedded tissue and development of antibodies to other markers is currently underway. The use of immunohistochemistry for evaluating these markers permits direct visualization of the tumor to avoid errors of sample size and contamination inherent in traditional molecular techniques and is a rapid, well-established technique familiar and available to surgical pathologists. Publication Types: Review Review, Tutorial PMID: 7906382 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1073: Nucleic Acids Res. 1992 Dec 25;20(24):6687-93. Plateau distributions of DNA fragment lengths produced by extended light exposure of extranuclear photosensitizers in human cells. Kvam E, Stokke T, Moan J, Steen HB. Department of Biophysics, Norwegian Radium Hospital, Montebello, Oslo. We have exploited properties of photosensitizers to study an aspect of the packing of chromatin in the cell nucleus. The fluorescent photosensitizers mesotetra(3-hydroxyphenyl) porphyrin and Photofrin II were both localized in the nuclear membrane and other membrane structures, but could not be found inside the nuclei. Light exposure of cells at 1 degrees C in the presence of the sensitizers induced DNA double-strand breaks. The length distributions of DNA fragments were determined by pulsed field gel electrophoresis. Because DNA damage is produced mainly via singlet oxygen diffusing less than 0.1 microns from the sensitizer, DNA double-strand breaks were supposedly produced within this distance of the nuclear membrane. Consistent with this, with prolonged illumination and with increasing concentrations of sensitizer the distribution of DNA fragment lengths reached a plateau level. In contrast, with the hydrophilic, intranuclear sensitizer meso-tetra(4-sulphonatophenyl)porphyrin, no such plateau level was found. The plateau distributions of DNA fragment lengths of different cell types had the same general shape with average fragment lengths ranging from 174 to 194 kilobasepairs. Particular genes, c-myc, fos and p53, were found on broad distributions of photocleaved fragment lengths. The results indicate that on each side of the genes the locus of the chromatin fibre situated close to the nuclear membrane, varied randomly. PMID: 1480490 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1074: Cancer. 1992 Dec 15;70(12):2772-7. Expression of p53 protein in invasive colorectal carcinomas of different histologic types. Hanski C, Bornhoeft G, Shimoda T, Hanski ML, Lane DP, Stein H, Riecken EO. Department of Gastroenterology, Klinikum Steglitz, Freien Universitat Berlin, Germany. BACKGROUND. This study was performed to determine whether morphologic differences of colonic cancer types can be related to different genotypes of these tumors. METHODS. Paraffin sections of 76 human invasive colorectal carcinomas were examined for the overexpression of p53 oncoprotein with the avidin-biotin complex-peroxidase staining procedure and CM-1 antiserum, which detects p53 protein in paraffin-embedded material. The tumors were categorized as mucinous (22 cases), most of which originated from adenomas, and nonmucinous, which were subdivided into carcinomas originating from adenoma-carcinoma sequence (ACS) (29 cases) and de novo (DN) carcinomas (25 cases). RESULTS. Nineteen DN carcinomas (76%), 21 ACS carcinomas (72%), and 8 mucinous carcinomas (36%) exhibited detectable amounts of p53 protein in the tumor cell nuclei. Strong overexpression of p53 protein coincided with a high percentage (> 40%) of stained nuclei in 40% of ACS and 48% of DN carcinomas versus 9% of mucinous tumors. The percentage of stained nuclei, intensity of staining, and distribution of the stained areas did not correlate with the grade of differentiation or the invasive edge of the tumors. Along with nuclear staining of the tumor area, a distinct perinuclear staining of normal epithelial cells adjacent to the tumor was observed in 48% of DN, 7% of ACS, and 9% of mucinous carcinomas. CONCLUSIONS. The current results, in combination with the recently published data on Ki-ras and c-myc alterations, indicate that mucinous carcinomas differ from nonmucinous colorectal carcinomas in their genetic lesions. PMID: 1451054 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1075: Blood. 1992 Dec 15;80(12):3205-16. Structural and functional analysis of oncogenes and tumor suppressor genes in adult T-cell leukemia/lymphoma shows frequent p53 mutations. Cesarman E, Chadburn A, Inghirami G, Gaidano G, Knowles DM. Department of Pathology, Columbia University, College of Physicians and Surgeons, New York, NY. The human T-cell lymphotropic virus type I (HTLV-I) is capable of inducing adult T-cell leukemia/lymphoma (ATLL). However, the long latency period between infection and development of ATLL, as well as the small fraction of the infected population that actually develops this disease, suggest that additional factors are involved in its pathogenesis. Therefore, we performed a molecular analysis of 10 cases of ATLL presenting in a nonendemic area that were shown to have HTLV-I sequences by polymerase chain reaction as well as clonal T-cell receptor beta gene rearrangements. We analyzed these cases for alterations in some of the oncogenes and tumor suppressor genes frequently involved in hematopoietic neoplasia. Specifically, we used a single-strand conformation polymorphism assay to determine the presence of mutations in the p53 tumor suppressor gene, as well as the K-RAS, N-RAS, H-RAS, and c-myc oncogenes. In addition, we studied the c-myc gene for rearrangements by Southern blotting and assessed expression of the retinoblastoma (Rb) and p53 genes by immunostaining. Analysis of the c-myc gene and the RAS family of oncogenes did not show any alterations. Also, the Rb gene was expressed in all cases analyzed. However, we found mutations of the p53 gene in 3 of the 10 cases and these results were confirmed by sequence analysis. In two of these cases, we showed by restriction fragment length polymorphism analysis of chromosome 17p sequences that the p53 mutations were accompanied by a loss of heterozygocity. Also, these mutations correlated with an altered pattern of p53 expression. Thus, mutations in the p53 locus may be a cofactor for the development of ATLL in some cases, whereas the c-myc, Rb, and RAS genes do not appear to be involved in these neoplasms. PMID: 1361372 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1076: Int J Cancer. 1992 Dec 2;52(6):851-5. Quantitation of biological tumor markers (p53, c-myc, Ki-67 and DNA ploidy) by multiparameter flow cytometry in non-small-cell lung cancer. Morkve O, Halvorsen OJ, Stangeland L, Gulsvik A, Laerum OD. Department of Thoracic Medicine, Gade Institute, Norway. Fifteen primary non-small-cell lung carcinomas (8 adenocarcinomas and 7 squamous-cell carcinomas) were analyzed by multiparameter flow cytometry for their expression of p53 and c-myc proteins. In addition, the fraction of cells staining with the proliferation-associated antibody Ki-67 and DNA ploidy was determined. These 4 biological markers were analyzed in parallel samples from a single-cell suspension made from fresh, frozen biopsies. Thus, the internal relationship between these markers within each tumor-cell population was established. Three different anti-p53 antibodies were used: PAb 421, PAb 1801 and PAb 240. All 15 tumors were p53-positive with the antibodies PAb 1801 and PAb 240, whereas only 9 were positive as judged by the antibody PAb 421. This indicates that the choice of p53 antibody is not irrelevant. Ten tumors were c-myc-positive; 7 of these were adenocarcinomas. The c-myc-positive tumors had a significantly higher level of p53 expression, judged by PAb 1801 and PAb 240, than c-myc-negative tumors. For PAb 421, there was no difference. We did not find any correlation between Ki-67 staining and expression of p53 and c-myc proteins, either with DNA ploidy, S-phase fraction or histological type. Our study indicates that there might be an association between accumulation of p53 protein and c-myc over-expression in non-small-cell lung cancer, and that this in particular might apply to adenocarcinomas. Furthermore, we show that multiparameter flow cytometry is a powerful tool in the study of the relationship between different markers in a cell population. PMID: 1334053 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1077: Oncogene. 1992 Dec;7(12):2455-60. c-myc and p53 gene expression in the differentiation of temperature-sensitive mutants of teratocarcinoma F9 cells. Kosaka M, Iwai SA, Nishina Y, Sumi T, Nishimune Y. Research Institute for Microbial Diseases, Dental Faculty, Osaka University, Japan. We have previously reported the isolation of several temperature-sensitive (ts) mutants of F9 cells. Further investigations showed that some mutants were induced to differentiate at non-permissive temperature of cell growth, accompanied by changes in the expression of various genes, whereas others were not. During the differentiation induced by shifting up to the non-permissive temperature, a rapid and transient decrease in both c-myc and p53 mRNA levels and rapid induction of c-jun mRNA were observed. These changes were specific in differentiation-inducible mutants and were not observed in a non-inducible mutant. In both types of mutants, the level of c-myc mRNA decreased in association with growth retardation at the non-permissive temperature. The p53 mRNA, however, showed specific increase in the differentiation-inducible ts mutants. These observations suggest distinct roles for p53 and c-myc from proliferation to differentiation in teratocarcinoma stem cells. PMID: 1461650 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1078: Nihon Kyobu Shikkan Gakkai Zasshi. 1992 Dec;30 Suppl:39-41. [Analysis of oncogenes and suppressor genes in lung cancer and bronchial lesions from high risk group] [Article in Japanese] Awaya Y, Hiyama K, Yamakido M. Department of Internal Medicine, Hiroshima University, School of Medicine, Japan. The authors investigated methods for analysis of oncogenes and tumor suppressor genes in lung cancers and bronchial lesions from high risk patients (retired poison gas factory workers). Amplifications of C-, L-, N-myc, length of terminal repeat array (TRA), mutations of p53 gene, p53 mRNA and K-ras genes were analysed in frozen specimens of surgically resected lung cancers. Various lesions including dysplasia, squamous metaplasia, goblet cell metaplasia, and basal cell hyperplasia were detected in the bronchial epithelium of biopsied specimens from retired poison gas factory workers. Analysis of p53 gene and k-ras gene mutations was performed on these formalin fixed, paraffin embedded samples, but no evidence of mutation has been found to date. PMID: 1306237 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1079: Cancer Res. 1992 Nov 15;52(22):6390-3. Mutations in the p53 gene in radiation-sensitive and -resistant human squamous carcinoma cells. Jung M, Notario V, Dritschilo A. Department of Radiation Medicine, Georgetown University School of Medicine, Washington, DC 20007. Five of six human squamous cell carcinoma (SCC) cell lines characterized as radiation sensitive (SQ-38, SCC-9, SQ-9G) or radiation resistant (SQ-20B, SCC-35, JSQ-3) exhibited alterations of the p53 gene. The point mutations and a deletion were detected by using single-stranded conformational polymorphism analysis and polymerase chain reaction-direct sequencing. Interestingly, three of three radiation-sensitive and two of three radiation-resistant cell lines revealed mutations in the p53 gene. Point mutations were located in exons 4, 6, and 8 (at codons 72 and 298 in JSQ-3; 273 in SCC-35; 196 in SQ-38), and deletions consisted of 32 base pairs between codons 274 and 285 in SCC-9 and 1 base pair at codon 271 in SQ-9G. Three mutations resulted in substitutions for an arginine residue. Immunocytochemical analysis confirmed p53 protein overexpression in SCC-35 cells which contained a missense mutation at codon 273. In contrast to previous studies which linked alterations in ras, myc, and raf expression with radiation resistance, this study indicates that mutations in the tumor suppressor gene, p53, do not directly correlate with such resistance. PMID: 1423286 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1080: Nature. 1992 Nov 12;360(6400):177-9. Erratum in: Nature 1992 Dec 3;360(6403):491. Abrogation by c-myc of G1 phase arrest induced by RB protein but not by p53. Goodrich DW, Lee WH. Center for Molecular Medicine, University of Texas Health Science Center, San Antonio 78245. Inactivating mutations of the retinoblastoma gene (RB) are found in a wide variety of tumour cells. Replacement of wild-type RB can suppress the tumorigenicity of some of these cells, suggesting that the RB protein (Rb) may negatively regulate cell growth. As activation of c-myc expression promotes cell proliferation and blocks differentiation, it may positively regulate cell growth. The c-myc protein is localized in the nucleus and can physically associate with RB protein in vitro, hence c-myc may functionally antagonize RB function. Microinjection of Rb in G1 phase reversibly arrests cell-cycle progression. Here we co-inject RB protein with c-myc, EJ-ras, c-fos or c-jun protein. Co-injection of c-myc, but not EJ-ras, c-fos or c-jun, inhibits the ability of Rb to arrest the cell cycle. The c-myc does not inhibit the activity of another tumour supressor, p53 (ref. 12). Thus, c-myc and RB specifically antagonize one another in the cell. PMID: 1436095 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1081: Environ Health Perspect. 1992 Nov;98:61-7. Relationship of H-ras-1, L-myc, and p53 polymorphisms with lung cancer risk and prognosis. Weston A, Caporaso NE, Perrin LS, Sugimura H, Tamai S, Krontiris TG, Trump BF, Hoover RN, Harris CC. Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, MD 20892. Proto-oncogenes (H-ras-1 and L-myc) and tumor-suppressor gene (p53) loci have been implicated in lung carcinogenesis. DNA restriction fragment length polymorphisms at these gene loci are being evaluated in a case-control study as markers predictive of risk for cancer or of prognosis when cancer is present. The cases and controls had a cigarette-smoking history of 40 or more pack years or other abnormalities in pulmonary function tests, their ages were closely matched (64 years for cases and 61 years for controls) and the ratio of Caucasians to African Americans was close to unity (cases, 0.95:1.00, controls, 1.00:0.88). The H-ras-1 gene contains an insertion deletion polymorphism. Inheritance of rare H-ras-1 alleles, defined by MspI digestion, confers a relative risk for lung cancer of 2.0 (95% confidence interval, 0.5-7.3) for Caucasians and 3.2 (0.9-11.6) for African Americans (74 cases, 67 controls). The L-myc gene sequence has a restriction site (EcoR1) polymorphism between the second and third exons. Inheritance of restriction site-present alleles was reported to confer poor prognosis (presence of lymph node metastases) in Japanese lung cancer patients. This hypothesis was tested in both case-control study subjects (56 cases, 55 controls) and additional surgical cases (40), but no evidence was found to support the hypothesis in the U.S. population. The p53 gene is a tumor-suppressor gene that can encode either a proline or an arginine in the 72nd residue. No associations was found between the minor allele (proline) and diagnosis of lung cancer (76 cases, 68 controls).(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 1486864 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1082: Cell Growth Differ. 1992 Nov;3(11):803-9. The gene for the rat heat-shock cognate, hsc70, can suppress oncogene-mediated transformation. Yehiely F, Oren M. Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel. In cells transformed by mutant mouse p53 plus ras, the former protein is found to be complexed with the heat-shock protein cognate hsc70. To determine whether hsc70 can directly affect neoplastic transformation, nonestablished rat embryo fibroblasts (REF) were transfected with rat genomic hsc70 DNA in conjunction with various oncogenes. We report here that the hsc70 gene could efficiently suppress focus induction by mutant p53 plus ras, as well as by myc plus ras. No inhibitory effect of hsc70 was detectable in assays monitoring the ability of REF to be immortalized by mutant p53, arguing against a nonspecific deleterious effect of the hsc70 genomic clone on REF survival and proliferation. Lines generated in the presence of the hsc70 plasmid produced augmented levels of hsc70. Plasmids encoding only short NH2-terminal fragments of hsc70 could also, in some cases, partially reduce oncogene-mediated focus formation. However, a maximal inhibitory effect required the production of a functional hsc70 protein. The data presented here raise the possibility that hsc70 may be directly involved in the modulation of oncogene-mediated transformation. PMID: 1467307 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1083: Biochem J. 1992 Oct 1;287 ( Pt 1):1-15. Nuclear protein phosphorylation and growth control. Meek DW, Street AJ. Department of Biochemistry, University of Dundee, Scotland, U.K. Publication Types: Review PMID: 1417761 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1084: Proc Natl Acad Sci U S A. 1992 Oct 1;89(19):9210-4. Growth arrest induced by wild-type p53 protein blocks cells prior to or near the restriction point in late G1 phase. Lin D, Shields MT, Ullrich SJ, Appella E, Mercer WE. Department of Microbiology and Immunology, Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107. Conditional expression of wild-type (wt) p53 protein in a glioblastoma tumor cell line has been shown to be growth inhibitory. We have now more precisely localized the position in the cell cycle where growth arrest occurs. We show that growth arrest occurs prior to or near the restriction point in late G1 phase of the cell cycle. The effect of wt p53 protein on the expression of four immediate-early genes (c-FOS, c-JUN, JUN-B, and c-MYC), one delayed-early gene (ornithine decarboxylase), and two late-G1/S-phase genes (B-MYB and DNA polymerase alpha) was also examined. Of this subset of growth response genes, only the expression of B-MYB and DNA polymerase alpha was significantly repressed. The possibility that decreased expression of B-MYB may be an important component of growth arrest mediated by wt p53 protein is discussed. PMID: 1409626 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1085: Leuk Lymphoma. 1992 Oct;8(3):167-88. The pathogenesis of AIDS lymphomas: a foundation for addressing the challenges of therapy and prevention. Karp JE, Broder S. Office of the Director, National Cancer Institute, Bethesda, Maryland 20892. The association between AIDS and a spectrum of malignancies relates to chronic, profound defects in both cellular and humoral mechanisms of immune surveillance. Ironically, as AIDS patients live longer in response to increasingly effective antiretroviral therapies, the incidence of AIDS-related malignancies will continue to rise. The emergence of non-Hodgkin's lymphomas (NHL) as a major sequela of HIV infection bears a striking relationship to depletion of CD4 lymphocytes, particularly below 50/mm3. The ability to interfere early in the course of active HIV infection with additional mechanisms that may promulgate transformed cell hyperproliferation and clonal expansion--growth factors, HIV itself or other viruses (Epstein-Barr, in particular), aberrant oncogene or tumor suppressor genes expression, factors that induce genetic instability or DNA damage or alter host or viral genome repair--might decrease the occurrence or prolong the time to development of AIDS-related malignancies. The development of antiretroviral strategies that confer long-term suppression of HIV activity and relative preservation of immune function are essential to the ultimate prevention of malignancies that arise as a consequence of HIV-induced immunosuppression. Publication Types: Review PMID: 1362682 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1086: Gan To Kagaku Ryoho. 1992 Oct;19(12):1971-6. [Genetic alterations in the genesis and development of ovarian cancer] [Article in Japanese] Okamoto A, Yokoyama S, Terashima Y. Dept. of Obstetrics and Gynecology, Jikei University School of Medicine, Tokyo, Japan. Genetic alterations of various cancers have been clarified by recent development of molecular biology. Multiple genetic alterations occur through the development of cancer. Both activation of proto-oncogenes and inactivation of tumor suppressor genes are important for the development of cancer. Alterations of oncogenes such as K-ras, c-erbB-2/HER-2/neu and c-myc, and those of tumor suppressor genes such as p53, RB and DCC have been reported in ovarian cancer. Allelic losses of the specific chromosomes, which suggest the existence of tumor suppressor genes on those chromosomes, also have been reported in ovarian cancer. Further studies on genetic alterations of ovarian cancer will clarify the mechanisms for the development of ovarian cancer and also will develop new methods for prevention, diagnosis and treatment in clinical. Publication Types: Review Review, Tutorial PMID: 1358031 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1087: Eur J Cancer B Oral Oncol. 1992 Oct;28B(2):145-52. In vitro and animal studies of the role of viruses in oral carcinogenesis. Park NH, Li SL, Xie JF, Cherrick HM. UCLA School of Dentistry, Los Angeles, California. The linkage of herpes simplex virus (HSV) and human papillomavirus (HPV) to the development of oral cancer has been studied. In spite of the presence of viral nucleic acids in some human oral cancer specimens, HSV alone is not carcinogenic in animals: repeated viral inoculation to mouse or hamster oral mucosa fails to produce tumours or histopathological evidence of malignancy. However, HSV demonstrates co-carcinogenicity in vivo: viral inoculation significantly enhances the oncogenic capacity of chemical carcinogens in the oral cavity of mice and hamsters. Though the detailed mechanisms of HSV cocarcinogenicity are unknown, HSV promotes the chemical carcinogen-induced activation of certain cellular proto-oncogenes and inactivation of p53 tumour suppressor gene. Human papillomaviruses type 16 (HPV-16) and 18 (HPV-18) demonstrate oncogenicity by transforming normal human oral keratinocytes in vitro. While normal cells exhibit a limited life-span, cells transformed by these viruses show immortality and altered morphology in comparison with their normal counterparts. The HPV-immortalised cells contain multiple copies of intact viral genome integrated into cellular chromosomes. These cells also express several viral-specific mRNAs including viral E6/E7 mRNAs. Notably, these cells contain low levels of p53 protein and overexpressed cellular myc proto-oncogene compared to their normal counterpart; however, the immortilised cell lines are non-tumorigenic in nude mice. PMID: 1339129 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1088: Tohoku J Exp Med. 1992 Oct;168(2):239-45. The molecular biology of lung cancer. Gazdar AF. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas. Lung cancer arises after a series of morphological changes, which take several years to progress from normal epithelium to invasive cancer. The morphological changes progress from hyperplasia, to metaplasia, to dysplasia, to carcinoma in situ, to invasive cancer and finally to metastatic cancer. Multiple molecular changes have been documented in lung cancers, both small cell (SCLC) and non-small cell (NSCLC) types. The number of changes has been estimated to be in double digits. These changes include activation of dominant oncogenes myc family, (K-ras and neu genes), as well as loss of recessive growth regulatory genes or anti-oncogenes (p53, and RB as well as unidentified gene or genes on chromosome 3). However, cytogenetic and molecular genetic studies indicate that multiple other specific sites of actual or potential DNA loss may be present in lung cancers. Other changes may include development of drug resistance, and production of growth factors and their receptors. It is tempting to associate specific molecular changes with specific morphological changes, as has been attempted in the colon. However, because of the difficulties in serially sampling the respiratory tract, such studies have not been performed to date. Documentation of molecular changes in premalignant lesions and prospective studies of their prognostic effects will be necessary for the design of rational chemoprevention trials. PMID: 1306309 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1089: Cancer Lett. 1992 Sep 30;66(2):155-64. Co-ordinate expression of c-fos, p53 and cytokeratin genes during the alteration of growth of human hepatoma cells. mRNA levels measured by reverse transcription and polymerase chain reaction. Kaneko Y, Tsukamoto A, Korokawa K. First Department of Medicine, University of Tokyo, Faculty of Medicine, Japan. Teleocidin, a tumor promoter, inhibited the proliferation, enhanced cytokeratin assembly and increased the type III procollagen production of PLC/PRF/5 hepatoma cells. Teleocidin transiently increased the levels of c-fos and p53 mRNAs measured by reverse transcription and polymerase chain reaction. This was followed by a reduction of c-myc mRNA and an increase of cytokeratin mRNA. The level of p120 mRNA was not remarkably altered. Sequential alterations of the expression of c-fos, p53, c-myc and cytokeratin genes induced by teleocidin may be responsible for the morphological and functional changes of hepatoma cells induced by this tumor promoter. PMID: 1382834 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1090: Exp Cell Res. 1992 Sep;202(1):161-6. An altered repertoire of fos/jun (AP-1) at the onset of replicative senescence. Irving J, Feng J, Wistrom C, Pikaart M, Villeponteau B. Department of Biological Chemistry, University of Michigan, Ann Arbor 48105-2007. With multiple divisions in culture, normal diploid cells suffer a loss of growth potential that leads to replicative senescence and a finite replicative capacity. Using quantitative RT-PCR, we have monitored mRNA expression levels of c-fos, c-jun, JunB, c-myc, p53, H-ras, and histone H4 during the replicative senescence of human fibroblasts. The earliest and the largest changes in gene expression occurred in c-fos and junB at mid-senescence prior to the first slowing in cell growth rates. The basal level of c-fos mRNA decreased to one-ninth that of the early-passage levels, while junB declined to one-third and c-jun expression remained constant. The decline in the basal c-fos mRNA level in mid-senescence should lead to an increase in Jun/Jun AP-1 homodimers at the expense of Fos/Jun heterodimers and may trigger a cascade of further changes in c-myc, p53, and H-ras expression in late-passage senescent fibroblasts. PMID: 1511730 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1091: Mol Biol (Mosk). 1992 Sep-Oct;26(5):1134-47. [Complex characteristics of the alterations of oncogenes HER-2/ERBB-2, HER-1/ERBB-1, HRAS-1, C-MYC and antioncogenes p53, RB1, as well as deletions of loci of chromosome 17 in colon carcinoma] [Article in Russian] Kniazev PG, Imianitov EN, Chernitsa OI, Nikiforova IF, Babenko VI, Bruderliain S, Plutalo OV, Kuz'min AI, Kaboev OK, Berlin IuA, et al. Abnormalities of some oncogenes, antioncogenes and losses of heterozygosity (LOH) of chromosome 11p, 17p, and 17q in colorectal carcinomas (CC) was studied. Amplification of ERBB-1/HER-1 oncogene was detected in 2 of 56 cases; ERBB-2/HER-2- in 4 of 62. There was a lack of evidence for C-MYC oncogene amplification (67 cases). LOH of chromosome 11p (HRAS-1 probe) was found in 2 of 37 informative (heterozygous) cases; such events were not accompanied by point mutations in "hot" codons (12th or 61st) in the remaining allele. Prevalence of A3 and A4 alleles of HRAS-1 oncogene (68 cases) as compared to healthy donors was noted. RB-1 (41 cases) and p53 (62 cases) suppressor genes did not show any alterations in Southern-blot analysis. LOH of chromosome 17p (YNZ-22 probe) was found in 15 of 26 heterozygous CC; 17q (THH-59 probe)--in 4 of 16. Analysis of 175th codon of p53 gene revealed only one case of mutation in 35 CC studied. Finally, we were able to detect genetic alterations in 23 of 40 (58%) CC, that were studied on each parameter using Southern-blot. We failed to find any correlation between various molecular abnormalities or clinical characteristics. The data obtained are in disagreement with the view concerning frequent involvement of p53 antioncogene in chromosome 17p deletions. PMID: 1470178 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1092: Cancer Res. 1992 Aug 15;52(16):4313-9. Hormone-regulated apoptosis results from reentry of differentiated prostate cells onto a defective cell cycle. Colombel M, Olsson CA, Ng PY, Buttyan R. Department of Urology, Columbia University, College of Physicians and Surgeons, New York, New York 10032. Castration initiates extensive apoptosis of the secretory epithelial cells lining the ducts of the rat ventral prostate, resulting in the striking regression of this male sexual accessory tissue. We had previously described the paradox of finding similar cascades of gene activity (c-fos greater than c-myc greater than hsp-70) induced during the early period of ventral prostate regression and during the regrowth of the ventral prostate gland initiated by testosterone replenishment. This common pattern of protooncogene expression during periods of predominant cellular apoptosis or proliferation caused us to examine further the possibility that the two cellular events occur through identical early molecular pathways. In the present study we demonstrate that apoptotic prostate epithelial cells incorporate bromodeoxyuridine into nuclear high-molecular-weight DNA prior to nuclear DNA fragmentation. The DNA synthetic activity occurs in coordination with a massive induction of proliferative cell nuclear antigen, a proliferation marker, in the nuclei of androgen-deprived prostatic epithelial cells. Moreover, this activity is also associated with the increased expression of mRNA encoding p53, a suppressor gene well known as a cell cycle-blocking agent. Our data indicate that quiescent (G0) prostate epithelial cells undergo apoptosis due to two sequential events initiated by testosterone depletion. The first event is the active reentry of these cells into the cell cycle. The second event is the apoptotic destruction resulting from the inability of the differentiated cells to successfully complete this cycle. PMID: 1353702 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1093: Oncogene. 1992 Aug;7(8):1661-5. Erratum in: Oncogene 1993 Jan;8(1):229. Modifications of cell cycle controlling nuclear proteins by transforming growth factor beta in the HaCaT keratinocyte cell line. Landesman Y, Pagano M, Draetta G, Rotter V, Fusenig NE, Kimchi A. Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel. PMID: 1385861 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1094: Oncogene. 1992 Aug;7(8):1541-7. Functional interaction of p53 with HPV18 E6, c-myc and H-ras in 3T3 cells. Chen TM, Defendi V. Department of Pathology, New York University Medical Center, New York 10016. Wild-type (wt) p53 has been suggested to be the product of a tumor-suppressor gene. Recently, it has been shown that the E6 oncoproteins of human papillomavirus (HPV) types 16 and 18, like the SV40 large T antigen, are physically associated with wt p53. We have investigated the functional interaction of wt p53 with the viral oncogene products of HPV16 and 18 and with cellular oncogenes by transfection of NIH3T3 cells with p53 wt alone or with several oncogene(s). We found that over-expression of HPV18 E6, c-myc or activated H-ras, like SV40 large T, can partially overcome the growth-inhibitory effect of wt p53 in NIH3T3 cells, while HPV16 E6 and E7, HPV18 E7, k-fgf, c-fos and mutant (mt) p53 do not. Further studies indicate that HPV18 E6 and c-myc can overcome the antiproliferative effect, but not the antitransforming effect, of wt p53, while activated H-ras can overcome both the antiproliferative and antitransforming effects of wt p53. These data show evidence of a functional interaction between HPV18 E6 and wt p53, and suggest that the cooperation of HPV E6 and cellular oncogenes c-myc and H-ras, which are activated in several cases of human cervical cancers, may be necessary to overcome completely the anti-oncogenic function of p53 in the development of these tumors. PMID: 1321402 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1095: Cancer Lett. 1992 Jul 31;65(1):61-71. Involvement of p53 mutation in the development of human salivary gland pleomorphic adenomas. Azuma M, Kasai Y, Tamatani T, Sato M. 2nd Department of Oral and Maxillofacial Surgery, Tokushima University School of Dentistry, Japan. We examined the status of the p53 mutation, a putative tumor suppressor gene, as well as the expressions of myc and mos oncogene products in human salivary gland pleomorphic adenoma cells in culture derived from four individuals using techniques which enabled selective and favourable growths of tumor cells. Culture techniques empolyed in this study consisted of type I collagen gel-coated dishes and serum-free medium as substrates and growth medium, respectively. Cells grown under above conditions were subjected to the analyses of p53, myc and mos expression. When analyzed by both immunocytochemical staining and immunoblot, mutant forms of p53 specifically detected by PAb240 were observed in three of 4 cases. However, none of the 4 cases expressed myc and mos oncogene products. These results may imply a role for p53 mutation in the development of human salivary gland pleomorphic adenomas. PMID: 1324786 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1096: Cell. 1992 Jul 10;70(1):153-61. Ras-induced hyperplasia occurs with mutation of p53, but activated ras and myc together can induce carcinoma without p53 mutation. Lu X, Park SH, Thompson TC, Lane DP. Department of Biochemistry, University of Dundee, Scotland. Using a reconstituted mouse prostate organ, the effects on endogenous p53 expression of the ras oncogene or of the ras + myc oncogenes were investigated. In this system the ras gene alone causes mild hyperplasia, but the combination of ras and myc leads to the formation of carcinomas. Surprisingly, while p53 mutations were found in cells derived from the reconstituted organs containing ras alone, no such mutations were found in the ras + myc-transformed cells. Their growth, unlike that of the cells containing ras alone, was not inhibited by transfection with plasmids encoding wild-type human p53. We suggest that expression of both activated ras and myc genes bypasses the need for p53 mutation by neutralizing the tumor suppressor activity of normal p53. PMID: 1623518 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1097: Oncogene. 1992 Jul;7(7):1383-90. Evidence for synergistic interactions between ras, myc and a mutant form of p53 in cellular transformation and tumor dissemination. Taylor WR, Egan SE, Mowat M, Greenberg AH, Wright JA. Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Canada. Mouse 10T1/2 cells were transfected with combinations of T24 H-ras, human c-myc and the proline 193 mutant form of p53. The three-gene ras/myc/p53 combination was significantly more efficient than single genes or double gene combinations in inducing transformed foci in vitro. An analysis of cell lines isolated after transfections with ras, ras/myc, ras/p53 and ras/myc/p53 indicated that the last combination contained significantly higher levels of ras protein than the other combinations, produced tumors in syngeneic mice with a shorter latency period, and exhibited an increased ability to form lung tumors in an in vivo experimental metastasis assay. Synergistic interactions between ras, myc and mutant p53 genes were observed in focus formation and metastasis assays, suggesting that the action of the three oncogenes in malignant transformation occurs along separate but interactive pathways. These results support a working model of oncogene cooperativity in which alterations in myc and p53 permit elevated expression of ras, which is important in a mechanism affecting both cellular transformation in vitro and tumor dissemination in vivo. PMID: 1620551 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1098: Eur J Cancer B Oral Oncol. 1992 Jul;28B(1):67-76. Oncogenes and tumour-suppressor genes in squamous cell carcinoma of the head and neck. Field JK. School of Dentistry, University of Liverpool. Cancer is now considered to be a multi-hit process which involves a number of aberrant genetic events culminating in malignant transformation. In squamous cell carcinoma (SCC) of the head and neck the action of both oncogenes and tumour-suppressor genes has been identified during the course of the disease. Cytogenetic analysis of these carcinomas has demonstrated chromosomal breakpoints, particularly in the regions of 1p22 and 11q13 together with frequent amplification of the proto-oncogenes in the 11q13 amplicon; int-2, hst-1 and bcl-1. Ras mutations have been infrequently identified in the Western World whereas ras over-expression has been a common finding and may be associated with the early development of head and neck cancer. C-myc over-expression appears to correlate with a poor prognosis for these patients. The tumour-suppressor gene p53 is also thought to be involved in the development of SCC in head and neck tumours and its aberrant expression is associated with a history of heavy smoking and heavy drinking. E-cadherin, a putative tumour-suppressor gene is down-regulated in poorly differentiated head and neck SCC and maybe important in nodal metastasis. A recent study has indicated that the Human Papilloma Virus (HPV 16 and 33) has a role in the aetiology of tonsillar carcinomas and HPV has been shown to produce transforming proteins which bind to and inactivate the p53 tumour suppressor gene. This evidence suggests that the possibility of a viral mechanism for the development of SCC in the head and neck should be considered. This paper proposes a series of genetic events to explain the development of SCC of the head and neck. Publication Types: Review Review, Tutorial PMID: 1330149 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1099: J Cell Biochem. 1992 Jun;49(2):208-15. Wild-type murine p53 represses transcription from the murine c-myc promoter in a human glial cell line. Moberg KH, Tyndall WA, Hall DJ. Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107. Here we analyzed the effect of the suppressor proto-oncogene p53 on transcription from the P2 promoter of the murine c-myc gene. c-myc promoter constructs were coupled to the chloramphenicol acetyl-transferase (CAT) gene and were transiently transfected into a human glial cell along with plasmids overexpressing wild-type or mutant p53. It was found that significant repression of c-myc transcription took place following cotransfection with wild-type but not mutant p53. However wild-type p53 did not suppress transcription from the SV40 early promoter or from the MHC promoter. Promoter-CAT constructs containing only the ME1a2 or E2F elements, from the P2 promoter, were repressed by p53, indicating that p53 may exert its effect at these two sites within the P2 promoter. Finally, when the SV40 T antigen and wild-type p53 were expressed together in glial cells the repressive effect of p53 was abolished. PMID: 1400626 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1100: Cancer Res. 1992 May 15;52(10):2823-9. Multiple oncogenes and tumor suppressor genes are structurally and functionally intact during hepatocarcinogenesis in hepatitis B virus transgenic mice. Pasquinelli C, Bhavani K, Chisari FV. Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California 92037. In the current study we sought to elucidate the molecular mechanisms which might contribute to hepatocarcinogenesis in a hepatitis B virus (HBV) envelope transgenic mouse model in which chronic hepatocellular injury and inflammation lead to regenerative hyperplasia and eventually to the development of chromosomal abnormalities and hepatocellular carcinoma (HCC), thereby reiterating many of the pathophysiological events that occur prior to the development of HCC in chronic HBV infection in humans. We have previously demonstrated that HBV envelope gene expression is decreased in regenerating hepatocytes and preneoplastic nodules early in the disease process and that expression of alpha-fetoprotein and the multidrug transporter gene mdr-III is activated in the tumors that develop in this model, but not prior to tumor development. In the current study, we examined the structure and expression of a large panel of dominant acting oncogenes and tumor suppressor genes in the liver at all stages of the disease process in order to determine the extent to which they contribute to hepatocarcinogenesis in these transgenic mice. To our surprise, no changes were observed in the structure or function of any of these genes, many of which are commonly activated in other rodent models of hepatocarcinogenesis but rarely activated in human HCC. These findings suggest that the HBV transgenic mouse model is different from most other rodent models of hepatocarcinogenesis and that it may relate more closely to the events involved in HBV-induced human hepatocarcinogenesis, where generalized chromosomal abnormalities are common, while structural and functional changes in most of the commonly studied positive-acting oncogenes examined herein are not. Since p53 and RB mutations have recently been reported to be late events in human hepatocarcinogenesis, the structural integrity of the RB locus and the absence of p53 mutations in the HBV transgenic mouse model suggest that they may represent a relatively early stage of hepatocellular tumorigenesis and that further manipulation of this model is warranted in order to more fully reproduce the molecular-genetic events that characterize HBV-induced HCC in humans. PMID: 1316229 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1101: Genes Dev. 1992 May;6(5):876-87. Immortalization of conditionally transformed chicken cells: loss of normal p53 expression is an early step that is independent of cell transformation. Ulrich E, Boehmelt G, Bird A, Beug H. Research Institute for Molecular Pathology, Vienna, Austria. Clones of mortal chicken fibroblasts and erythroblasts transformed by temperature-sensitive v-src and v-erb B oncoproteins have been developed into immortal cell lines that retain the conditional transformed phenotype. The expressions of two tumor suppressor genes, the retinoblastoma (Rb) gene and the p53 gene, were investigated during senescence, crisis, and cell line establishment. In temperature-sensitive (ts)-v-erb B erythroblasts and ts-v-src fibroblasts (as well as in v-myc macrophages), loss of p53 mRNA or expression of a mutated p53 gene invariably occurred in the early phase of immortalization. In contrast, expression of the Rb gene was unchanged at all stages of immortalization. Inactivation of the original temperature-sensitive oncogene led to loss of the transformed phenotype in fibroblasts and to differentiation in erythroblasts, even in lines that were immortal and lacked p53. The results demonstrate that the process of immortalization is distinct from cell transformation, probably requiring different mutational events. PMID: 1577279 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1102: Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi. 1992 May;25(2):59-68. Absence of genomes of DNA tumor viruses and expression of oncogenes and growth factors in two esophageal carcinoma cell lines of Chinese origin. Wong FH, Hu CP, Chen SC, Yu YT, Chang C. Graduate Institute of Microbiology and Immunology, National Yang-Ming Medical College, Taipei, Taiwan, Republic of China. To study the oncogenesis of human esophageal carcinoma, the presence of DNA sequences homologous to several DNA tumor viruses and the expression of oncogenes and growth factor genes were examined in two esophageal carcinoma cell lines of Chinese origin, CE48T/VGH and CE81T/VGH. Southern blot analyses failed to detect sequences homologous to hepatitis B virus (HBV), Epstein-Barr virus (EBV), herpes simplex virus type 2 (HSV-2), cytomegalovirus (CMV) or human papilloma virus (HPV) genomes. Northern blot analyses revealed that c-myc, c-src, c-H-ras, c-abl, c-sis, and p53 genes were expressed. In addition, transcripts of transforming growth factor alpha (TGF alpha), TGF beta, and platelet derived growth factor A (PDGF A) genes were detected. These studies suggest that DNA tumor viruses may not be involved in the carcinogenesis of esophageal carcinoma. However, cooperation among different oncogenes and the production of growth factors may play an important role in that carcinogenesis. PMID: 1473373 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1103: J Urol. 1992 Apr;147(4):1142-6. Loss of the 17p chromosomal region in a metastatic carcinoma of the prostate. Macoska JA, Powell IJ, Sakr W, Lane MA. Laboratory of Molecular Genetics, Michigan Cancer Foundation, Detroit. Genetic alterations of multiple loci that serve as markers for the induction and progression of disease have been identified in several adenocarcinomas, but not in adenocarcinoma of the prostate. To determine if similar genetic alterations occur in prostate carcinoma and could serve as markers for the extent of clinical disease, we have examined 23 predominantly moderately-differentiated, localized prostate carcinomas and one prostatic dysplasia for changes in the structure and copy number of ten selected genes. These genes include 1) those important to androgen metabolism in the prostate, the androgen receptor and steroid 5 alpha reductase genes; 2) those that map to the 10q (PLAU) and 7q (MET) chromosomal regions found deleted in some prostate carcinomas, and 3) proto-oncogenes (ERBB2, INT2, and MYC) and tumor suppressor gene loci (RB1, TP53 and D17S5) found altered in adenocarcinomas of the breast, colon and lung. Gene alterations were detected in one specimen, a lymph node metastasis from a poorly differentiated tumor. This specimen exhibited loss of heterozygosity for two loci putatively active in tumor suppression, TP53 and D17S5, on the short arm of chromosome 17. This study indicates that gross genetic alterations were not evident and could not be used as markers of tumor development in well- or moderately-differentiated, localized lesions, but that loss of the 17p region may be a useful marker for advanced carcinomas in the prostate. PMID: 1552612 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1104: Cancer Res. 1992 Apr 1;52(7):2000-3. Altered steady-state levels of the messenger RNAs for c-myc and p53 in L1210 cell lines resistant to deoxyadenosine. Cory JG, Cory AH, Long SD, Carter GL, Johnson CE. Department of Biochemistry, East Carolina University School of Medicine, Greenville, North Carolina 27858. L1210 cell lines, selected for resistance to deoxyadenosine due to the loss of allosteric inhibition of ribonucleotide reductase by dATP, had altered steady-state levels of the mRNAs for c-myc, fos, and p53. Wild-type L1210 cells had constitutive steady-state levels of c-myc and p53 with little or no fos mRNA. Two different deoxyadenosine-resistant cell lines (Y8 and ED2) had elevated steady-state levels of c-myc and fos but essentially no p53 mRNA. Hydroxyurea-resistant L1210 cells had the same levels of c-myc, fos, and p53 as the wild-type cells. There was no amplification of the gene for c-myc in the Y8 or ED2 cell lines. The half-life for c-myc mRNA was essentially the same in the wild-type and the Y8 and ED2 cells. Nuclear runoff experiments showed that the rates of transcription for c-myc in the Y8 and ED2 cells were elevated and could account for the increased steady-state levels of c-myc in these two cell lines. The transcription rate for p53 mRNA was not decreased in the Y8 and ED2 cells and therefore did not account for the loss of the steady-state levels of p53 in the cells. Cycloheximide treatment of the Y8 and ED2 cells resulted in a marked increase in the steady-state p53 mRNA level, indicating that a protein which was rapidly turned over was responsible for the extremely short half-life of p53 mRNA in these two cell lines. PMID: 1551129 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1105: Nippon Sanka Fujinka Gakkai Zasshi. 1992 Apr;44(4):391-6. [Immunohistochemical studies of recessive oncogene p53 and N-myc oncogene expression in 7, 12 dimethylbenz (a) anthracene-induced rat ovarian tumors] [Article in Japanese] Kataoka A, Nishida T, Sugiyama T, Hirakawa N, Maruuchi T, Imaishi K, Yakushiji M. Department of Obstetrics and Gynecology, Kurume University School of Medicine. In the present study, the expressions of p53 and N-myc gene were analyzed immunohistochemically in rat ovarian tumors induced by 7,12 dimethylbenz (a) anthracene (DMBA). 1) p53 could be seen in the nucleolei of tumor cells. The positive rates were: adenomas 17%, adenocarcinomas 37%, sarcomas 0%, mixed mullerian tumor 0% and epidermal cysts 100%. Neither the serial-allografted tumor nor DMBA-OC-1 was positive. 2) N-myc could be seen in the cytoplasm and perinuclear cytoplasm of tumor cells. The positive rates were: adenomas 33%, adenocarcinomas 77%, sarcomas 100%, mixed mullerian tumors 100% and epidermal cysts 100%. Both the serial-allografted tumor and DMBA-OC-1 were positive. 3) The positive rates in both p53 and p21 were: adenocarcinoma 20% and epidermal cysts 100%. The positive rates in both N-myc and p21 at the were: adenoma 17%, adenocarcinoma 50%, sarcoma 33%. Both the serial-allografted tumor and DMBA-OC-1 were positive. Only two cases were positive for p53, N-myc and p21. p53 was detected in most of the adenomas. 4) The positive rate for both N-myc and p21 was higher than that for both p53 and p21. This was similar to other reports. The results suggested that p53 plays a role in precancerous tumor as a recessive oncogene. It was supposed that tumors with N-myc gene expression were had malignant growth characteristics. PMID: 1318915 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1106: Cancer Res. 1992 Feb 15;52(4):1032-5. Infrequent p53 mutation in mouse tumors with deregulated myc. Gutierrez MI, Bhatia K, Siwarski D, Wolff L, Magrath IT, Mushinski JF, Huppi K. Pediatrics Branch, National Cancer Institute, NIH, Bethesda, Maryland 20892. An invariant genetic lesion in mouse plasmacytomas is deregulated expression of c-myc as a consequence of chromosomal translocation. However, retroviral and transgenic studies suggest that additional genetic lesions may contribute to the genesis of plasmacytomas. The p53 tumor suppressor gene is a likely contributor to this genetic lesion, since there is a high incidence of p53 mutation in Burkitt's lymphomas and B-ALL (L3), both of which contain translocations involving c-myc analogous to those in plasmacytomas. In addition, p53 has been shown to be a transcriptional modulator of c-myc expression. In a survey of 27 mouse plasmacytomas by single-strand conformation polymorphism, we identified a single mutation (3.7% incidence), suggesting that p53 lesions are not frequent contributors to plasmacytomagenesis. A similar study of macrophage-monocyte tumors generated by a c-myc-containing retrovirus also indicates a lack of p53 involvement in deregulated c-myc expression. These results suggest that the specific maturation stage of transformed B-lymphocytes, independent of c-myc deregulation, may be the critical factor which determines the involvement of mutant p53. PMID: 1737333 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1107: Br J Cancer. 1992 Feb;65(2):208-14. Inactivation of p53 gene in human and murine osteosarcoma cells. Chandar N, Billig B, McMaster J, Novak J. Orthopaedic Research Laboratory, Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania 15212. We examined structure and expression of the p53 and Rb genes in a C3HOS transplantable mouse model of osteosarcoma. The results were compared to analogous studies conducted with five human osteosarcoma cell lines. The p53 gene was found rearranged in the mouse tumour. The rearrangement mapped to the first intron region of the p53 gene and as a result, no p53 expression could be detected in C3HOS tumours. Using p53 genomic probes, we have detected the same rearrangement in the original radiation-induced tumour and the various clones that were isolated from it. Deletion and rearrangement of the p53 gene were also found in three out of five of the human osteosarcoma cell lines (MG-63, G-292, Saos-2). No p53 expression could be detected in these three cell lines. In the affected human osteosarcoma cell lines, the rearrangement involved the first intron region. In addition, the mouse tumor was analysed for structural and expression changes in the Rb and the c-myc genes. Normal expression of both genes were detected in the murine tumour. Only one (Saos-2) human osteosarcoma cell line exhibited gross structural alteration in the retinoblastoma gene. The results suggest that the inactivation of p53 may be an important step in the development of osteosarcomas, and that a rearrangement affecting the first intron is common in osteosarcomas. PMID: 1739619 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1108: Mol Carcinog. 1992;5(3):190-8. Association of induction of a fully tumorigenic phenotype in murine radiation-induced T-lymphoma cells with loss of differentiation antigens, gain of CD44, and alterations in p53 protein levels. Gjerset RA, Arya J, Volkman S, Haas M. UCSD Cancer Center, University of California, San Diego, La Jolla 92093-0063. We investigated the mechanism of radiation induction of murine thymic lymphomas by studying the characteristics of primary x-ray-induced thymic lymphoma (PXTL) cell lines and of their oncogene-induced, progressed progeny. It is widely thought that proto-oncogene alterations are associated with the induction of murine lymphomas; however, few, if any primary murine radiation-induced lymphomas possess (proto-)oncogene alterations. Independently derived cell lines grown directly (i.e., without in vivo transplantation) from thymic lymphomas of irradiated C57BL/6 mice possess the properties of immortalized pre-T cells and lack many of the characteristics of "tumor cells". PXTL cells are poorly tumorigenic upon transplantation, do not clone in methylcellulose cultures, are growth factor dependent and autocrine, and lack consistent chromosome and oncogene abnormalities. However, the thymic lymphomas are malignant and cause the death of each afflicted mouse. PXTL cells expressed two immunologically distinct forms of the tumor suppressor protein p53 that have moderately increased stability (t1/2 = 1 h) when compared with p53 of normal splenic T lymphocytes. Early PXTL cells could progress in vitro to a fully tumorigenic phenotype after infection with retroviruses encoding the c-myc and v-ras oncogenes. Progressed T-lymphoma cells acquired growth factor independence, a highly transplantable and tumorigenic phenotype, and the ability to quantitatively clone in methylcellulose cultures. Progressed lymphoma cells coordinately downregulated the expression of five T-cell differentiation markers, upregulated the expression of CD44 (Pgp-1), and harbored vastly elevated levels of two immunologically distinct forms of p53. Our results suggest that the early thymic lymphomas consist of differentiation-inhibited, immortal pre-T cells that are precursors to progressed, fully tumorigenic T-lymphoma cells. PMID: 1586448 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1109: Prog Clin Biol Res. 1992;376:321-30. Comparable oncogene and tumor suppressor gene alterations in rat and human osteosarcomas. Isfort RJ, Cody DB, Lovell G, Doersen CJ. Procter & Gamble Company, Miami Valley Laboratories, Cincinnati, Ohio 45239-8707. PMID: 1528926 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1110: Curr Top Microbiol Immunol. 1992;182:493-9. Loss of p53 expression in Myc-induced B lineage tumors. Scheuermann RH, Bauer SR. Department of Pathology, University of Texas Southwestern Medical Center, Dallas 75235-9072. Tumors are formed following the accumulation of several genetic changes in genes which normally function to regulate cell growth. As yet it is unclear why multiple mutations are required, which type of alterations can collaborate with each other, and if collaboration is cell-type specific. In our myc transgenic mouse model system both point mutations and loss of mRNA expression for the p53 tumor suppressor gene have been found in the myc-induced B-lineage tumors arising spontaneously in these mice. This demonstrates the collaboration between these two growth control genes in cellular transformation. The observation that alterations in the expression of p53 is a common phenomenon in tumors formed in myc transgenic mice as well as a variety of different types of human tumors suggests that inactivation of the p53 growth control pathway may be required for transformation, and that alterations in p53 itself might be the most efficient way to achieve this inactivation. An analysis of the molecular mechanism for p53 alterations has implications for what kind of factors, both environmental and physiological, can influence tumor formation. The identification of collaboration groups has implications for the process of tumor formation, growth regulation, and will some day be important for the diagnosis of cancer, the prognosis of the individual and the design of specific therapeutic agents for treatment. PMID: 1490390 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1111: Cancer Treat Res. 1992;61:45-57. Suppressor genes in breast cancer: an overview. Steeg PS. It is apparent that multiple genetic events occur in the development and progression of breast cancer. From the limited data available, no consistent temporal pattern of mutational events is required. This conclusion is consistent with data in colorectal carcinoma, where the number of mutational events, and not the order, appears to be relevant. Several authors have questioned whether the multiple mutational events occur independently or whether significant associations were evident. Cropp et al. postulated that two sets of mutational events occurred simultaneously in a higher degree of breast tumors than expected based on chance: Set 1 consisted of deletions on 11p, 17p, 18q, and int-2 and myc amplifications; set 2 consisted of 17q, 1p, and 3p deletions. Sato et al., analyzing another tumor cohort for simultaneous mutations, noted a correlation of 17p and 16q deletions, 13q and 17p deletions, and 17p deletion with erbB-2 amplification. Clearly, concordant data on this issue will require the use of large breast tumor cohorts for a comprehensive set of probes. The reasons why mutations to specific genes on different chromosomes tend to occur coordinately is unknown, but may involve common flanking and/or intron sequences at high risk for certain types of mutational events. Another interesting question is the degree to which alterations, but not homozygous inactivation, of suppressor genes occur and its phenotypic consequences. In this chapter, evidence was presented for the amplification of a DCC allele in breast cancer and for variable RB protein expression in breast tumors as a consequence of allelic deletion. For many of the metastasis suppressor genes, a simple reduction in their expression, or an alteration in their expression over the normal cellular regulatory controls, may be sufficient to fuel the metastatic process. The data suggest a more complex regulation of the cancer phenotype by suppressor genes than by recessive inactivation alone. Why do many sporadic cancers, including breast cancer, appear to require alterations to multiple suppressor genes, as compared to diseases such as retinoblastoma, where a single suppressor gene appears to control the cancer phenotype? The answer to this question is unknown, but most theories are based on the hypothesis that suppressor genes act to control cellular responses to either other cells or signals in the microenvironment. In retinoblastoma all cells can carry a germ-line mutation. Cells carrying the RB mutation can interact with both the embryonic and differentiated microenvironments; the specific interaction of mutated cells with the embryonic retinal microenvironment may trigger the onset of retinoblastoma.(ABSTRACT TRUNCATED AT 400 WORDS) Publication Types: Review Review, Tutorial PMID: 1360244 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1112: Anticancer Res. 1992 Jan-Feb;12(1):11-20. Oncoprotein (c-myc, c-erbB1, c-erbB2, c-fos) and suppressor gene product (p53) expression in squamous cell carcinomas of the lung. Clinical and biological correlations. Volm M, Efferth T, Mattern J. German Cancer Research Center, Heidelberg. The expression of the protooncogene encoded proteins (c-erbB1, c-erb B2, c-myc, c-fos) and the suppressor gene product p53 was analyzed in 81 human squamous cell carcinomas of the lung and correlated with clinical parameters of the patients (patient survival, presence of metastases and tumor stage) and with biological characteristics of the tumors (tumor growth in nude mice, DNA-ploidy, proliferative activity, drug-resistance and P-glycoprotein or gluathione S-transferase expression). By means of immunohistochemistry, expression of c-erbB1 oncoprotein (EGF-receptor) was detected in 79% of the tumors, c-erbB2 (c-neu) proteins in 35%, c-myc proteins in 48%, c-fos proteins in 41%, and p53 in 43% of the tumors. Patients with c-erbB1 positive tumors had a poor prognosis (p = 0.021). In addition, these tumors were more frequently drug resistant (p = 0.0067). A significant correlation between the growth of the squamous lung carcinomas in nude mice and c-fos oncoprotein expression was demonstrated (p = 0.017). Therefore, EGF-receptor and c-fos products may serve as prognostic factors for the aggressiveness of squamous cell carcinomas of the lung and for the response of these tumors to chemotherapy. No significant correlation was found between the expression of the c-erbB1 or c-fos gene products and stage, metastasis and DNA-ploidy. In contrast to these results, no relationship was found between c-neu or c-myc gene products expression and any of the clinical or biological parameters examined. Aneuploid squamous cell carcinomas of the lung expressed p53 more frequently than diploid tumors (p = 0.027). However, there was no significant difference between p53 expression and stage, survival of patients, metastasis, growth of the tumors in nude mice, proliferative activity and drug-resistance of the tumors. PMID: 1348920 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1113: Adv Intern Med. 1992;37:153-71. The molecular genetics of lung cancer. Carbone DP, Minna JD. University of Texas Southwestern Medical Center, Dallas. Publication Types: Review Review, Tutorial PMID: 1348393 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1114: Pathol Annu. 1992;27 Pt 1:321-42. Oncogenes and antioncogenes in human breast carcinoma. Leslie KO, Howard P. Publication Types: Review PMID: 1346552 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1115: Proc Natl Acad Sci U S A. 1991 Dec 1;88(23):10657-61. Mutations in p53 as potential molecular markers for human breast cancer. Runnebaum IB, Nagarajan M, Bowman M, Soto D, Sukumar S. Molecular Biology of Breast Cancer Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037. Based on the high incidence of loss of heterozygosity for loci on chromosome 17p in the vicinity of the p53 locus in human breast tumors, we investigated the frequency and effects of mutations in the p53 tumor suppressor gene in mammary neoplasia. We examined the p53 gene in 20 breast cancer cell lines and 59 primary breast tumors. Northern blot analysis, immunoprecipitation, and nucleotide sequencing analysis revealed aberrant mRNA expression, over-expression of protein, and point mutations in the p53 gene in 50% of the cell lines tested. A multiplex PCR assay was developed to search for deletions in the p53 genomic locus. Multiplex PCR of genomic DNA showed that up to 36% of primary tumors contained aberrations in the p53 locus. Mutations in exons 5-9 of the p53 gene were found in 10 out of 59 (17%) of the primary tumors studies by single-stranded conformation polymorphism analysis. We conclude that, compared to amplification of HER2/NEU, MYC, or INT2 oncogene loci, p53 gene mutations and deletions are the most frequently observed genetic change in breast cancer related to a single gene. Correlated to disease status, p53 gene mutations could prove to be a valuable marker for diagnosis and/or prognosis of breast neoplasia. PMID: 1961733 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1116: Nippon Rinsho. 1991 Dec;49(12):88-96. [Molecular pathology of oncogenes and anti-oncogenes in diagnosis of colonic polyps] [Article in Japanese] Monden T, Morimoto H, Nakanishi H, Fukunaga M, Shimano T, Mori T. Second Department of Surgery, Osaka University Medical School. PMID: 1787590 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1117: Nippon Naika Gakkai Zasshi. 1991 Oct 10;80(10):1687-93. [Molecular biology of liver neoplasms] [Article in Japanese] Toda G. PMID: 1663536 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1118: J Virol. 1991 Aug;65(8):4160-8. Simian virus 40 can overcome the antiproliferative effect of wild-type p53 in the absence of stable large T antigen-p53 binding. Michael-Michalovitz D, Yehiely F, Gottlieb E, Oren M. Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel. In simian virus 40 (SV40)-transformed cells, a tight complex is formed between the viral large T antigen (large T) and p53. It has been proposed that this complex interferes with the antiproliferative activity of p53. This notion was tested in primary rat fibroblasts by assessing the ability of SV40-mediated transformation to be spared from the inhibitory effect of wild-type (wt) p53. The data indicate that relative to transformation induced by myc plus ras, SV40-plus-ras-mediated focus formation was indeed much less suppressed by p53 plasmids. A majority of the resultant cell lines made a p53 protein with properties characteristic of a wt conformation. Furthermore, cell lines expressing stably both SV40 large T and a temperature-sensitive p53 mutant continued to proliferate at a temperature at which this p53 assumes wt-like properties and normally causes a growth arrest. Surprisingly, at least partial resistance to the growth-inhibitory effect of wt p53 was also evident when transformation was mediated by an SV40 deletion mutant, encoding a large T which does not bind p53 detectably. In addition to supporting the idea that SV40 can overcome the growth-restrictive activity of wt p53, these findings strongly suggest that at least part of this effect does not require a stable association between p53 and large T. PMID: 1649323 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1119: J Immunol. 1991 Jul 15;147(2):698-704. Differential regulation of the tumor suppressor molecules, retinoblastoma susceptibility gene product (Rb) and p53, during cell cycle progression of normal human T cells. Terada N, Lucas JJ, Gelfand EW. Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206. We have activated resting human T lymphocytes to study the roles of the putative cell cycle control gene products, retinoblastoma susceptibility gene product (Rb) and p53, in regulating cell proliferation. After stimulation with phorbol, 12,13, dibutyrate and the calcium ionophore, ionomycin, which triggers a rapid entry of cells into G1 phase, we demonstrated Rb phosphorylation 24 h later, well before the onset of DNA synthesis. This finding, in contrast to reports using proliferating cell lines, implies that Rb phosphorylation is not a proximal event regulating the G1 to S transition. The production of p53 became detectable 3 to 6 h after addition of phorbol, 12,13,-dibutyrate and ionomycin, and peaked at 30 to 42 h. To further delineate the relationship of the synthesis and metabolism of the proteins to cell cycle progression, we used three agents to arrest progression of activated T cells at various points in the cell cycle. Aphidicolin arrested the cells at the G1/S boundary, whereas deferoxamine, an iron chelator, arrested the cells at an earlier stage of the cell cycle. Cyclosporin A blocked T cell activation at the earliest point in the cell cycle. In the presence of aphidicolin, Rb phosphorylation and p53 production proceeded normally whereas cyclosporin A inhibited both events. Although deferoxamine completely prevented Rb phosphorylation, p53 production was unaffected, suggesting a differential regulation of the two molecules. Our results place Rb phosphorylation and p53 production in the hierarchy of genetic events that are thought to regulate T lymphocyte progression through the cell cycle. PMID: 1906503 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1120: Exp Cell Res. 1991 Jul;195(1):20-6. Erratum in: Exp Cell Res 1991 Oct;196(2):365. EGF-dependent growth inhibition in MDA-468 human breast cancer cells is characterized by late G1 arrest and altered gene expression. Prasad KA, Church JG. Terry Fox Cancer Research Labs, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Canada. The MDA-468 human breast cancer cell line displays the unusual phenomenon of growth inhibition in response to pharmacological concentrations of EGF. This study was initiated with the objective of elucidating the cellular mechanisms involved in EGF-induced growth inhibition. Following EGF treatment the percentage of MDA-468 cells in G1 phase increased, together with a concomitant depletion in S and G2/M phase populations, as revealed by flow cytometry of DNA content. The apparent G1 block in the cell cycle was confirmed by treating the cells with vinblastine. DNA synthesis was reduced to about 35% of that measured in control, untreated cells after 48 h of EGF treatment, as measured by the incorporation of [3H]thymidine. DNA synthesis returned to normal following the removal of EGF from the growth-arrested cells. In order to locate the EGF-induced event responsible for the G1 arrest more precisely, we examined the expression of certain cell cycle-dependent genes by Northern blot analysis. EGF treatment did not alter either the induction of the early G1 marker, c-myc, or the expression of the late G1 markers, proliferating cell nuclear antigen, and thymidine kinase. However, EGF-treated cells revealed down regulation of p53 and histone 3.2 expression, which are expressed at the G1/S boundary and in S phase, respectively. These results indicate that EGF-induced growth inhibition in MDA-468 human breast cancer cells is characterized by a reversible cell cycle block at the G1/S boundary. PMID: 1675999 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1121: Oncogene. 1991 Jul;6(7):1251-7. Status of c-myc, p53 and retinoblastoma genes in human papillomavirus positive and negative squamous cell carcinomas of the anus. Crook T, Wrede D, Tidy J, Scholefield J, Crawford L, Vousden KH. Ludwig Institute for Cancer Research, St. Mary's Hospital Medical School, London, UK. We have examined a series of squamous cell carcinomas (SCC) of the anus, anal intraepithelial neoplasia grade III (AINII) lesions and haemorrhoids for the presence of sequences from transforming human papillomavirus (HPV) types by polymerase chain reaction (PCR)/Southern blotting. In addition, the same DNAs have been analysed for abnormalities in the c-myc, p53 and retinoblastoma (Rb-1) gene loci by Southern blotting. HPV16 sequences were detected in a total of 38 of 50 (76%) and HPV18 sequences in 4 of the 50 cancers (8%). Of 12 haemorrhoids examined, none contained HPV16 or HPV18 sequences. Amplification of c-myc was demonstrated in 15 of the 50 cancers (30%), of which 13 were HPV16 positive, and one also positive for HPV18. Amplification of c-myc was not observed in the 5 AINIII or any of the 41 haemorrhoid DNAs analysed. Rearrangement of c-myc was not seen in any of the DNAs. Gross rearrangement, or loss of p53 or Rb-1 loci was not observed in any normal or tumor tissue. However, in preliminary analysis of p53 sequence, three tumours negative for HPV were heterozygous for p53 point mutation whereas six HPV positive tumours and two haemorrhoids were wild-type sequence throughout exons four to ten. PMID: 1650445 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1122: Proc Natl Acad Sci U S A. 1991 Jun 15;88(12):5413-7. p53 mutations in human lymphoid malignancies: association with Burkitt lymphoma and chronic lymphocytic leukemia. Gaidano G, Ballerini P, Gong JZ, Inghirami G, Neri A, Newcomb EW, Magrath IT, Knowles DM, Dalla-Favera R. Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY 10032. We have investigated the frequency of p53 mutations in B- and T-cell human lymphoid malignancies, including acute lymphoblastic leukemia, the major subtypes of non-Hodgkin lymphoma, and chronic lymphocytic leukemia. p53 exons 5-9 were studied by using genomic DNA from 197 primary tumors and 27 cell lines by single-strand conformation polymorphism analysis and by direct sequencing of PCR-amplified fragments. Mutations were found associated with (i) Burkitt lymphoma (9/27 biopsies; 17/27 cell lines) and its leukemic counterpart L3-type B-cell acute lymphoblastic leukemia (5/9), both of which also carry activated c-myc oncogenes, and (ii) B-cell chronic lymphocytic leukemia (6/40) and, in particular, its stage of progression known as Richter's transformation (3/7). Mutations were not found at any significant frequency in other types of non-Hodgkin lymphoma or acute lymphoblastic leukemia. In many cases, only the mutated allele was detectable, implying loss of the normal allele. These results suggest that (i) significant differences in the frequency of p53 mutations are present among subtypes of neoplasms derived from the same tissue; (ii) p53 may play a role in tumor progression in B-cell chronic lymphocytic leukemia; (iii) the presence of both p53 loss/inactivation and c-myc oncogene activation may be important in the pathogenesis of Burkitt lymphoma and its leukemic form L3-type B-cell acute lymphoblastic leukemia. PMID: 2052620 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1123: Biomed Environ Sci. 1991 Jun;4(1-2):73-92. Biochemical and molecular epidemiology of cancer. Sugimura H, Weston A, Caporaso NE, Shields PG, Bowman ED, Metcalf RA, Harris CC. Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Rockville, Maryland 20892. Examples of practical approaches to molecular epidemiology of human cancer are described. Biomarkers of carcinogen exposure or inherited host factors for cancer susceptibility are discussed. Major advances have been made in the detection of carcinogenmacromolecular adducts through the use of high performance liquid chromatography, immunoaffinity chromatography, the 32P-postlabeling assay, enzyme immunoassays, gas chromatography/mass spectroscopy and synchronous spectrophotofluorimetry. The polycyclic aromatic hydrocarbon-DNA adducts are the most extensively studied in this field and together with antibodies to these adducts found in human serum, they have become useful indicators of exposure to carcinogens. Assays for various kinds of alkyl-DNA adducts have also been developed and the presence of these adducts have been documented in human tissues. Carcinogen-protein adducts have proven to be useful molecular dosimeters of carcinogen exposure. For example, 4-aminobiphenyl hemoglobin adducts are highly correlated with exposure to tobacco smoke. The study of the molecular aspects of interindividual differences in the metabolism and activation of xenobiotics and other genetic markers [DNA-restriction fragment length polymorphisms (RFLPs), mutations, and functional loss of specific genes in carcinogenesis] is an emerging new field that is discussed in the context of genetic susceptibility to cancer. The cytochrome P450 phenotypes and acetylation phenotype are examples of genetic markers that indicate an individual's potential for metabolism of exogenous substances. Further, inherited genetic polymorphic markers, e.g., DNA-RFLPs at protooncogene loci (HRAS-1 and L-myc) have been examined in a case-control study of lung cancer. Data concerning mutations of protooncogenes (H-, K-, and N-RAS) and tumor suppressor genes (retinoblastoma and p53 genes) in various common cancers are providing evidence of multiple genetic lesions that occur during the multistage process of carcinogenesis. Publication Types: Review PMID: 1910603 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1124: Br J Cancer. 1991 Jun;63(6):851-8. Oncogenes in human testicular cancer: DNA and RNA studies. Peltomaki P, Alfthan O, de la Chapelle A. Department of Medical Genetics, University of Helsinki, Finland. Oncogene dosage and expression were studied in 16 testicular neoplasms, 14 of germ cell and two of non-germ cell origin. In comparison with normal DNA, tumour DNA of a total of eight patients (seven with germ cell neoplasm and one with testicular lymphoma) showed increased dosages of KRAS2, PDGFA, EGFR, MET and PDGFB. The most frequent (occurring in six tumours) and prominent (up to 3-4-fold) increases were detected in the dosages of KRAS2 (on chromosome 12p) and PDGFA (chromosome 7p), relative to a reference locus from chromosome 2. Importantly, there was a similar increase in 12p dosage in general in these tumours, suggesting the presence of the characteristic isochromosome 12p marker. On the contrary, possible 7p polysomy (assessed by molecular methods) did not explain the PDGFA (or EGFR) changes in all cases. NRAS, MYCN, CSFIR, MYB, MYC, ABL, HRASI, TP53, and ERBB2 did not reveal any consistent alterations in tumour DNA. In RNA dot blot assays the expression of KRAS2, PDGFA, EGFR, or MYC was generally not increased in the tumour samples when compared to that in normal testicular tissue of the same patients although there was interindividual variation in mRNA levels. It thus appears that while oncogene dosage changes occur in a proportion of testis cancers, they are often part of changes in large chromosomal regions or whole arms and are seldom accompanied by altered expression. PMID: 1829952 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1125: Environ Health Perspect. 1991 Jun;93:133-4. Oncogenes and tumor-suppressor genes. Lehman TA, Reddel R, Peiifer AM, Spillare E, Kaighn ME, Weston A, Gerwin BI, Harris CC. Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, MD 20892. The functional role of oncogenes in human lung carcinogenesis has been investigated by transfer of activated oncogenes into normal cells or an immortalized bronchial epithelial cell line, BEAS-2B. Transfection of v-Ha-ras, Ki-ras, or the combination of myc and raf into BEAS-2B cells produced tumorigenic cell lines, while transfection of raf or myc alone produced nontumorigenic cell lines. In addition to studying the pathogenic role of oncogenes, we are attempting to define negative growth-regulating genes that have tumor-suppressive effects for human lung carcinomas. Our strategy to identify tumor-suppressor genes involves loss of heterozygosity studies, monochromosome-cell fusion, and cell-cell fusion studies. Loss of heterozygosity studies have revealed consistent allelic DNA sequence deletions on chromosome 17p in squamous cell carcinomas, while large cell carcinomas and adenocarcinomas retained this locus. Mutations in p53, a tumor-suppressor gene located on chromosome 17p, have been observed. Cell-cell hybrid clones produced from fusion of nontumorigenic BEAS-2B cells with tumorigenic HuT292DM cells generally are nontumorigenic. The mechanistic role of the known tumor-suppressor genes Rb-1 and p53 in the development of human lung carcinomas is being investigated in this epithelial cell model of human bronchogenic carcinogenesis. Publication Types: Review Review, Tutorial PMID: 1685442 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1126: Proc Natl Acad Sci U S A. 1991 May 15;88(10):4128-32. Expression from the murine p53 promoter is mediated by factor binding to a downstream helix-loop-helix recognition motif. Ronen D, Rotter V, Reisman D. Department of Cell Biology, Weizmann Institute of Science, Rehovot, Israel. Expression of the p53 gene plays an important role in the regulation of cellular proliferation and malignant transformation. Overexpression of mutant forms of p53 is in fact a common feature of many transformed cells. Studies dealing with the transcriptional regulatory regions of the p53 gene indicate that, unlike most promoters transcribed by RNA polymerase II, the p53 promoter contains no TATA-like sequence upstream of the transcription start site. Here we demonstrate that the murine p53 promoter contains a cis-acting element that maps downstream to the transcription initiation site. The integrity of this element is required for high-level expression from the promoter in transformed cells. By DNase I protection and mobility-shift analysis, we show that a nuclear factor binds to this downstream element through the consensus recognition sequence for the helix-loop-helix (HLH)-containing proteins of the myc/MyoD family of transcriptional regulators. We propose that the activity of one or more members of this family of transcription factors is an important determinant in the expression of p53 and that at least one level of p53 overexpression in transformed cells may thus be due to aberrant expression of the relevant factor(s). Furthermore, the possibility that the regulation of expression of p53 occurs, in part, by means of a potential HLH-containing factor provides a possible mechanism for the suppression of proliferation by the MyoD family of transcriptional regulators. PMID: 1851994 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1127: Cancer Lett. 1991 Jan;56(1):45-51. Transcription of N-myc and proliferation-related genes is linked in human neuroblastoma. Raschella G, Negroni A, Giubilei C, Romeo A, Ferrari S, Castello MA, Dominici C. Division of Physics and Biomedical Sciences, CRE ENEA Casaccia, Rome, Italy. A definite association between the transcription of N-myc oncogene and proliferation-related genes, histone H3, c-myc and p53, was found in a set of 12 primary untreated neuroblastomas and a metastasis of one of these at relapse. Molecular analysis allowed us to discriminate between actually proliferating and non-proliferating tumors, and suggested a link between N-myc and proliferation. Flow cytometric analysis of DNA distribution was less reliable for assessing tumor proliferative activity. Our data also seem to indicate a down-regulation of c-myc by N-myc in human neuroblastoma. PMID: 2004353 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1128: Ontogenez. 1991 Jan-Feb;22(1):47-52. [The space-time distribution of the mRNA of the nuclear proteins c-myc and P-53 in the development of the clawed toad studied by hybridization in situ] [Article in Russian] Luk'ianov SA, Zaraiskii AG. We studied distribution of mRNA for nuclear protooncogene c-myc and nuclear protein P-53 in mature oocytes and embryos of Xenopus laevis from the stage of fertilization up to the stage of hatching by in situ hybridization with histological sections. mRNA for c-myc was present in all cells of the embryo at all studied developmental stages. Between the stage of fertilization and up to the late blastula, mRNA concentration for c-myc decreased progressively in all embryonic cells. During gastrulation a local increase in the concentration of this messenger was found in dorsal mesoderm and ectoderm. At the stage of neurula increased concentration of mRNA for c-myc was observed in all cells of the embryo but the hybridization signal increased particularly distinctly in cells of the neural tube. In studies of P-53 mRNA distribution hybridization signal was detected only in brain cells after stage 20 of development (after closure of the neural folds) and up to the stage of hatching. PMID: 1857586 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1129: Gan To Kagaku Ryoho. 1991 Jan;18(1):14-21. [Diagnosis of colorectal cancer from DNA level] [Article in Japanese] Shirasawa S, Yanagawa Y, Sasazuki T. Department of Genetics, Kyushu University, Fukuoka, Japan. The inherited cancer-inducing disease familial polyposis coli (FPC) provides an excellent model not only for studying tumor progression in colorectal cancer but also for elucidating molecular mechanisms in general oncogenesis. This paper reviewed recent remarkable progresses of molecular mechanisms in colorectal tumorigenesis. This is concerned with the various kinds of genetic alterations that accumulate in the development from normal mucosa to adenoma, and then to adenocarcinoma in comparison with FPC and sporadic cases. This review included also information on the localization of FPC major gene. These observations indicate that in cases of colorectal tumorigenesis several genetic alterations may be involved, including activation of K-ras gene, deregulated expression of c-myc gene or c-fos gene and inactivation of tumor suppressor genes such as p53 and DCC genes, as well as the loss of heterozygosity. The observation suggest that adenomas will have undergone several gene or chromosome mutations before reaching to the fully malignant state. Therefore, DNA diagnosis for colorectal tumors in the clinical level may contribute to more accurate prognosis and better results for further therapy. Publication Types: Review Review, Tutorial PMID: 1846282 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1130: Proc Natl Acad Sci U S A. 1991 Jan 1;88(1):139-43. Degradation of nuclear oncoproteins by the ubiquitin system in vitro. Ciechanover A, DiGiuseppe JA, Bercovich B, Orian A, Richter JD, Schwartz AL, Brodeur GM. Department of Biochemistry, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa. Nuclear oncoproteins are among the most rapidly degraded intracellular proteins. Previous work has implicated the ubiquitin-mediated proteolytic system in the turnover of short-lived intracellular proteins. In the present study, we have evaluated the potential role of the ubiquitin system in the degradation of the specific nuclear oncoproteins encoded by the N-myc, c-myc, c-fos, p53 and E1A genes. Each of these nuclear oncoproteins was synthesized in vitro by transcription of the appropriate cDNA and translation of the resulting mRNA in the presence of [35S]methionine. Degradation of labeled proteins was monitored in the ubiquitin cell-free system. ATP stimulated the degradation of all the proteins between 3- and 10-fold. The degradation was completely inhibited by neutralizing antibody directed against the ubiquitin-activating enzyme, E1, the first enzyme in the ubiquitin-mediated proteolytic cascade. Moreover, degradation in E1-depleted lysates could be restored in each case by the addition of affinity-purified E1. These data suggest that the ubiquitin system mediates the degradation of these oncoproteins in vitro. Degradation of other proteins, such as superoxide dismutase, cytochrome c, enolase, RNase A, and ornithine decarboxylase, is not mediated by the ubiquitin cell-free system. This suggests that the nuclear oncoproteins studied here possess specific signals that target them for rapid turnover by this proteolytic pathway. Furthermore, the relative sensitivity to degradation of various E1A mutants in vivo is also maintained in the cell-free system, suggesting that the ubiquitin pathway may play a role in the cellular degradation of these proteins as well. PMID: 1846034 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1131: Princess Takamatsu Symp. 1991;22:71-6. Tumor suppressor genes involved in metastasis of lung and colorectal carcinomas. Yokota J, Ookawa K, Nishikawa R, Sameshima Y. Section of Studies on Metastasis, National Cancer Center Research Institute, Tokyo, Japan. Inactivation of tumor suppressor genes is now believed to play an important role in various progression stages of human cancers. To clarify the possible involvement of tumor suppressor gene inactivation in the acquisition of metastatic potential in lung and colorectal carcinoma cells, we examined various genetic alterations in both primary tumors and metastases obtained from patients with lung and colorectal carcinomas. In lung carcinoma, loss of heterozygosity on chromosomes 3p, 13q, and 17p is a common genetic alteration, and both RB and p53 genes are inactivated as a result of chromosome 13q and 17p losses. In some cases, allelic loss on chromosome 11p and amplification of myc family oncogenes occur during tumor progression. In colorectal carcinoma, p53 and DCC alterations were detected in 100% of metastases, and sequential accumulation of allelic losses on chromosomes 13q, 14q, and 18q in the process of metastasis was observed. These results indicate that a subset of tumor suppressor genes is involved in metastasis of lung and colorectal carcinomas. Publication Types: Review Review, Tutorial PMID: 1844253 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1132: Dokl Akad Nauk SSSR. 1991;321(4):846-9. [Gene product p53 is involved in the regulation of activity of the c-fos proto-oncogene promotor] [Article in Russian] Vikhanskaia FL, Pospelova TV, Volkov IV, Kukushkin AN, Svetlikova SB, Poslepov VA. PMID: 1806357 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1133: Oncogene Res. 1991;6(1):1-12. Interleukin-3 and phorbol esters induce different patterns of immediate-early gene expression in an interleukin-3 dependent cell line. McCubrey JA, Steelman LS, McKearn JP. Department of Microbiology & Immunology, East Carolina University School of Medicine, Greenville, North Carolina 27858. The myeloid interleukin-3 (IL-3) dependent cell line, FDC-P1, enters the G0 stage of the cell cycle after IL-3 deprivation for 24 hr. The expression of 13 protooncogenes and immediate-early genes was compared with 4 "control" genes after the addition of either IL-3 or phorbol myristate acetate (PMA) to IL-3-deprived cells. mRNA transcripts encoding c-myc and the T-cell receptor c-gamma gene were induced to high levels only after IL-3 addition, whereas c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 were induced transiently only after PMA addition. The remaining genes (fra-1, p53, jun-D, c-Ha-ras, c-Ki-ras, c-raf, beta-actin, ornithine decarboxylase, and histone 2B) were detected after culture with either IL-3 or PMA. When cells were serum- and IL-3-deprived, c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 were detected after exposure to either serum or PMA. Moreover, culture with cycloheximide and PMA resulted in superinduction of these genes, whereas cycloheximide and IL-3 addition did not. mRNAs encoding these genes had half-lives of 10-20 min after PMA treatment, whereas that of beta-actin was longer (greater than 2 hr), suggesting that short mRNA half-lives contributed to the transient nature of these genes. Although c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 expression can be detected in IL-3-dependent cells after exposure to either PMA or serum, these genes were not detected after IL-3 addition, which allows cell-cycle progression. These results document the existence of IL-3 and PMA-responsive genes and demonstrate that IL-3 and protein kinase C agonists can induce distinct patterns of gene expression. PMID: 1705318 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1134: Oncogene. 1990 Dec;5(12):1769-74. Synergism between pairs of immortalizing genes in transformation assays of rat embryo fibroblasts. Peacock JW, Matlashewski GJ, Benchimol S. Ontario Cancer Institute, Toronto, Canada. A number of cellular and viral genes encode proteins that play a role in the establishment of normal cells in culture. In addition, these genes cooperate with activated ras genes to induce cellular transformation. We show that ras-dependent transformation of rat embryo fibroblasts is more efficient when two establishment genes are used together compared with one alone. Both quantitative and qualitative differences in the efficiency of transformation were detected. The number of transformed foci generated was greater than the sum of the foci obtained with ras and each of the establishment genes used separately. In addition, the foci had a distinct morphology. Synergism was seen between the HPV-16 E7 gene and certain mutant alleles of the cellular p53 gene as well as between E7 and c-myc. PMID: 2178238 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1135: Nippon Rinsho. 1990 Aug;48(8):176-86. [Studies of oncogene expression at the cellular level by in situ hybridization] [Article in Japanese] Morimoto H, Monden T, Miyoshi Y, Murotani M, Kawasaki Y, Shimano T, Mori T. Osaka University Medical School, Second Department of Surgery. PMID: 2255079 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1136: Leukemia. 1990 Aug;4(8):590-4. Rearrangements of the Pim-1, c-myc, and p53 genes in Friend helper virus-induced mouse erythroleukemias. Dreyfus F, Sola B, Fichelson S, Varlet P, Charon M, Tambourin P, Wendling F, Gisselbrecht S. INSERM U 152, Institut Cochin de Genetique Moleculaire, Paris, France. The Friend helper leukemia virus (F-MuLV) induces in mice leukemias of the erythroid, lymphoid, and myeloblastic lineages. Erythroleukemic cell DNAs were examined for genetic alterations at loci described as common proviral integration regions in MuLV-induced myeloid or lymphoid leukemias or in Friend complex-induced erythroleukemias. No alteration of the Fim-1, Fim-2, Fim-3, pvt-1, and Spi-1 loci were detected in 17 erythroleukemias, p53 gene rearrangement was observed in 6 (30%) erythroleukemias and was always associated with a loss of the germ line allele. Interestingly, genetic alterations were also detected at two loci, c-myc and Pim-1, previously described as common provirus integration regions in T lymphoid leukemias. Rearrangements of these two genes were often associated with p53 gene alteration within the same tumor. PMID: 2143796 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1137: Oncogene. 1990 Aug;5(8):1187-93. Gene expression in melanoma cell lines and cultured melanocytes: correlation between levels of c-src-1, c-myc and p53. Chenevix-Trench G, Martin NG, Ellem KA. Joint Oncology Program, Queensland Institute of Medical Research, Brisbane, Australia. The molecular genetics of melanoma is little understood and has concentrated largely on DNA analyses. We have examined mRNA levels of 21 different oncogenes, antioncogenes, growth factors and proteases in cultured melanocytes and 17 melanoma cell lines. C-mel, c-erb-B2, c-myc, c-src-1, p53, platelet derived growth factor A chain, gro, transforming growth factor alpha, epidermal growth factor receptor and tissue plasminogen activator were all expressed in at least some cell lines. Most striking was the finding that there are significant intercorrelations of c-myc, p53 and c-src-1 levels, and between p53 and c-erb-B2, which may be due to common regulatory control of these genes in cells of the melanocytic lineage. PMID: 1697409 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1138: Br J Cancer. 1990 Jul;62(1):78-84. Gene expression in oestrogen-dependent human breast cancer xenograft tumours. Thompson AM, Steel CM, Foster ME, Kerr D, Paterson D, Deane D, Hawkins RA, Carter DC, Evans HJ. Department of Surgery, Royal Infirmary of Edinburgh, UK. Xenograft tumours from an oestrogen-dependent human breast cancer cell line MCF-7 have been established and characterised in thymectomised, irradiated female CBA strain mice. There was evidence for selection in xenografts of a subpopulation of MCF-7 cells with an altered pattern of gene expression as measured by mRNA levels compared with the original cells in vitro. Tumorigenicity increased significantly on repeated animal passage but oestrogen dependence was retained. Following injection of the mice with oestrogen, mitosis was induced in the tumour cells with associated increases in thymidine uptake and percentage of cells in S-phase. In accord with these changes, c-myc and p53 expression were increased and TGF-beta was suppressed. Thereafter the expression of the c-myc and p53 genes fell whilst that of the TGF-beta gene was induced as the oestrogenic-stimulus declined. The oestrogen-regulated mRNA pS2 showed a biphasic response to oestrogen and levels declined as the serum oestrogen fell to undetectable levels. This xenograft system demonstrates that changes in transcription of oncogenes, growth factor and oestrogen-regulated genes can be detected in vivo in response to oestrogen. It thus provides an in vivo model for studies of the biochemical and molecular basis for therapeutic manipulation of hormone-sensitive human breast cancer. PMID: 2390487 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1139: Cancer Res. 1990 Jun 1;50(11):3193-8. Molecular analysis of early growth-associated events during the differentiation of F9 cells into embryoid bodies. Whitman MM, Shen YM, Soprano D, Soprano KJ. Department of Microbiology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140. Mouse F9 teratocarcinoma cell lines can be induced to differentiate into either parietal endoderm or embryoid bodies which contain visceral endoderm-like cells. The nature of the early molecular events involved in these two differentiation pathways has not yet been fully elucidated. Moreover, since the process of differentiation is often accompanied by changes in cell growth, it is often difficult to determine which of the events that do occur during the early stages of differentiation are a direct result of the process of differentiation and which events are indirect results that occur as a consequence of altered cell growth. In the experiments reported here we have attempted to distinguish between these two possibilities by examining the patterns of expression of a representative group of growth-associated genes (i.e., c-myc, p53, and histone H3) when F9 cell aggregates are induced to differentiate into embryoid bodies containing visceral endoderm. By analysis of the patterns of growth-associated gene expression in both retinoic acid treated and nontreated F9 cell aggregates, we were able to classify early events as differentiation-specific events (events which occurred only following retinoic acid treatment of aggregates) or nondifferentiation-specific events caused by reduction in cell growth (events which occurred even when aggregates were not treated with retinoic acid). Our results show that F9 cells differentiated into embryoid bodies containing visceral endoderm-like cell exhibit an early reduction in both growth and c-myc mRNAs which is neither retinoic acid-specific nor differentiation-specific. However, following this initial response to aggregation, constant levels of c-myc mRNA are maintained despite continued reduction in growth. Thus, it appears that alteration in c-myc expression is a differentiation-specific event along the pathway to formation of visceral endoderm. Interestingly, however, the nature and time course of this alteration in c-myc expression in F9 cells' differentiation into visceral endoderm is different from that observed in F9 cells differentiated into parietal endoderm. PMID: 2139801 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1140: Blood. 1990 Jan 1;75(1):180-9. Rearrangement and expression of p53 in the chronic phase and blast crisis of chronic myelogenous leukemia. Mashal R, Shtalrid M, Talpaz M, Kantarjian H, Smith L, Beran M, Cork A, Trujillo J, Gutterman J, Deisseroth A. Department of Hematology, University of Texas M.D. Anderson Cancer Center, Houston 77030. We tested a population of over 60 patients with chronic myelogenous leukemia (CML) for changes in the structure and expression of the p53 gene, which is located on chromosome 17. Six of 27 (22%) blast crisis samples and 3 of 5 (60%) accelerated phase samples had rearrangements of chromosome 17, whereas only 3 of 42 (7%) chronic phase patients had cytogenetic changes in chromosome 17. There was no loss of heterozygosity during the transition to blastic crisis among seven individuals who were informative for polymorphic probes for regions in or around the p53 gene on 17p. One patient in the chronic phase and one patient in the blastic phase of the 61 CML patients studied exhibited rearrangements of the p53 gene that were detectable by Southern analysis. One p53 allele was rearranged in the chronic phase patient and both p53 alleles were rearranged in the blastic phase patient. The p53 messenger RNA (mRNA) was of normal size (2.8 kb) in chronic phase and blast crisis, and the expression of the p53 gene was at least as high or higher in blast crisis as in the chronic phase of CML. The high incidence of abnormalities of chromosome 17 in blast-crisis CML found in our studies and the discovery of rearrangements of the p53 gene in two CML patients studied suggest that further study with probes for the p53 gene and anonymous polymorphic sites in chromosome 17 should be conducted in CML. PMID: 1967214 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1141: Exp Mol Pathol. 1989 Dec;51(3):264-74. Tissue-specific expression of c-Ha-ras in premalignant gastrointestinal mucosae. Meltzer SJ, Zhou D, Weinstein WM. Department of Medicine, University of Maryland, Baltimore. The molecular mechanisms underlying premalignant gastrointestinal diseases, such as ulcerative colitis and Barrett's esophagus, remain unknown. For this reason, the expression of the protooncogene c-Ha-ras was studied in ulcerative colitis and Barrett's esophagus. Total cellular RNA was extracted from different regions of the gastrointestinal tract in these two diseases. Expression of c-Ha-ras was greater in proximal than in distal colon and undetectable in Barrett's esophagus. These regional differences in expression were not seen with the control gene beta-actin or with the protooncogenes c-myc and p53. In order to evaluate structural factors contributing to expression, amplification and methylation of c-Ha-ras DNA were studied in these tissues by Southern and slot blotting. No amplification of c-Ha-ras or six other protooncogenes was detected. These data suggest tissue-specific regulation of c-Ha-ras expression in the gastrointestinal tract in certain premalignant disease states. PMID: 2557232 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1142: J Virol. 1989 Dec;63(12):5440-4. p53-plus-ras-transformed rat embryo fibroblasts express tumor-specific transplantation antigen activity which is shared by independently transformed cells. Frey AB, Levine AJ. Department of Biology, Princeton University, New Jersey 08544-1014. p53-plus-ras-transformed rat cell lines express a tumor-specific transplantation antigen that is common to a number (85%) of independently derived p53-plus-ras-transformed cell lines. This has been shown by immunizing rats with irradiated p53-plus-ras-transformed cells and demonstrating protection of these animals by subsequent live-cell tumor challenge. Several c-myc-plus-ras-transformed cell lines (54% of the lines tested) and one adenovirus E1a-plus-ras-transformed cell line (9% of those tested) were shown to share a common tumor-specific transplantation antigen by their ability to immunize a rat against a p53-plus-ras cell line challenge. Several experimental approaches have been used to fractionate and identify the antigen common to these cell lines. The experimental results reported here make it clear that the p53 protein common to most of these transformed cell lines is not likely to be the tumor-specific transplantation antigen. PMID: 2531235 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1143: Proc Natl Acad Sci U S A. 1989 Nov;86(22):8763-7. Wild-type p53 can inhibit oncogene-mediated focus formation. Eliyahu D, Michalovitz D, Eliyahu S, Pinhasi-Kimhi O, Oren M. Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel. Mutant forms of the p53 cellular tumor antigen elicit neoplastic transformation in vitro. Recent evidence indicated that loss of normal p53 expression is a frequent event in certain types of tumors, raising the possibility that such loss provides transformed cells with a selective growth advantage. Thus, it was conceivable that the mutants might contribute to transformation by abrogating normal p53 function. We therefore studied the effect of plasmids encoding wild-type (wt) p53 on the ability of primary rat embryo fibroblasts to be transformed by a combination of mutant p53 and ras. It was found that wt p53 plasmids indeed caused a marked reduction in the number of transformed foci. Furthermore, wt p53 plasmids also suppressed the induction of transformed foci by combinations of bona fide oncogenes, such as myc plus ras or adenovirus E1A plus ras. On the other hand, plasmids carrying mutations in the p53 coding region totally failed to inhibit oncogene-mediated focus induction and often even slightly stimulated it. Hence, such mutations completely abolished the activity of wt p53 that is responsible for the "suppressor" effect. The latter fact is of special interest, since similar mutations in p53 are often observed in human and rodent tumors. The inhibitory effect of p53 was most pronounced when early-passage cells were used as targets, whereas established cell lines were less sensitive. These data support the notions that wt p53 expression may be restrictive to neoplastic progression and that p53 inactivation may play a crucial role in tumorigenesis. PMID: 2530586 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1144: J Biol Chem. 1989 Oct 25;264(30):18019-23. Nuclear and nucleolar targeting sequences of c-erb-A, c-myb, N-myc, p53, HSP70, and HIV tat proteins. Dang CV, Lee WM. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205. Protein import into the cell nucleus requires specific binding of nuclear proteins to the nuclear pore complex. Based on amino acid sequence "motifs" of known nuclear targeting signals, we identified peptides within a number of nuclear proteins with likely nuclear targeting potential and tested their function by transfecting into cells fusion genes that produce the cytoplasmic "reporter" protein, pyruvate kinase (PK), joined to the test sequence. Sequences within c-myb (PLLKKIKQ), N-myc (PPQKKIKS), p53 (PQPKKKP), and c-erb-A (SKRVAKRKL) oncoproteins that direct PK hybrids into the nucleus were identified. A peptide (GRKKRRQRRRAP) of the human immunodeficiency virus (HIV) tat protein (Tat), which contains two short basic regions, targets fusion proteins to the nucleolus. The COOH-terminal basic Tat region (QRRRAP) does not target PK hybrid proteins into the nucleus, but mutation of two basic amino acids in this region decreases but does not abolish nucleolar accumulation mediated by the entire Tat nucleolar targeting sequence. Moreover, the c-Myc nuclear targeting sequence fused to the COOH-terminal basic Tat region (PAAKRVKLDQRRRAP) effectively localizes PK hybrids to the nucleus and nucleolus. A similar sequence (FKRKHKKDISQNKRAVRR) in the human heat-shock protein HSP70 also localizes PK to the nucleus and nucleolus. PMID: 2553699 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1145: Cancer Res. 1989 Mar 15;49(6):1554-61. Production of hepatocellular carcinoma by oval cells: cell cycle expression of c-myc and p53 at different stages of oval cell transformation. Braun L, Mikumo R, Fausto N. Department of Pathology, Brown University, Providence, Rhode Island 02912. In rats maintained on a carcinogenic diet (choline deficient containing 0.1% ethionine), the levels of c-myc and p53 mRNAs increased by 4 wk after animals were placed on the diet. Cell isolation studies showed that the change in c-myc takes place in oval cells, while p53 increases predominantly in oval cells but also in hepatocytes. To determine whether this increase is a consequence of cell proliferation or is associated with transformation, we have developed an in vitro model of hepatocarcinogenesis using epithelial cells isolated from the livers of rats fed the carcinogenic diet. When maintained in vitro with infrequent subculture, this cell line (LE/6) undergoes spontaneous transformation. Inoculation s.c. of the transformed cells into nude mice yields tumors histologically identified as hepatocellular carcinoma. We have used these cell lines to compare the cell cycle expression of c-myc and p53 mRNAs in untransformed, partially transformed, and tumorigenic LE/6 cells. We find that the expression of both genes is under cell cycle control in untransformed and partially transformed cells. However, complete transformation of this cell line is associated with constitutive expression of myc but not p53 transcripts. On the basis of this work we suggest that constitutive expression of c-myc may be a late event in hepatocarcinogenesis. PMID: 2647288 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1146: Oncogene. 1989 Feb;4(2):165-73. Modulation of the c-myb, c-myc and p53 mRNA and protein levels during induced murine erythroleukemia cell differentiation. Richon VM, Ramsay RG, Rifkind RA, Marks PA. The DeWitt Wallace Research Laboratory, Memorial Sloan-Kettering Cancer Center, Cornell University, New York, NY 10021. The induction of murine erythroleukemia cells (MELC) to terminal differentiation by hexamethylene bisacetamide (HMBA) is accompanied by changes in the levels of c-myb and c-myc mRNA, and in p53 protein levels. We simultaneously examined the effects of HMBA on modulation of c-myb, c-myc and p53 mRNA and protein levels, and examined the relationship between these changes and commitment to terminal cell division. In MELC cultured with HMBA, c-myb protein levels paralleled c-myb mRNA levels except at 24h, when the protein level was equivalent to the level in control cultures, whereas the mRNA had decreased. The c-myc protein paralleled c-myc mRNA throughout induction. The p53 mRNA and protein behaved in a discordant fashion. The p53 protein decreased to very low levels between 4 and 8 h and remained low, while the mRNA, which initially decreased, reaccumulated by 24 and 48 h. Transfer of MELC after 12 to 48 h of culture with HMBA to medium without inducer resulted in rapid (less than 3 h) reaccumulation of the c-myb mRNA, c-myb protein, and p53 protein, and cessation of recruitment of cells to commitment. Cells already induced to commit to terminal differentiation continued to express the differentiated phenotype. PMID: 2648254 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1147: Prog Clin Biol Res. 1989;316B:171-81. Induced differentiation of murine erythroleukemia cells (MELC) by polar compounds: marked increased sensitivity of vincristine resistant MELC. Marks PA, Michaeli J, Jackson J, Richon VM, Rifkind RA. DeWitt Wallace Research Laboratory, Memorial Sloan-Kettering Cancer Center, New York, New York. Hexamethylene bisacetamide (HMBA) is a most effective compound as an inducer of MELC differentiation. HMBA-mediated terminal differentiation of MELC is a multistep process. There is a latent period during which a number of changes occur including the appearance of Ca2+ and phospholipid independent PKC activity in the cytosol, and modulation in expression of several genes, including c-myc, c-myb, c-fos and the p53 genes. During this latent period there is neither detectable commitment to terminal differentiation (including terminal cell division) or increased transcription of the globin genes. HMBA-mediated commitment to terminal differentiation is first detected at about 12 hr and increases in a stochastic fashion, until over 95% of the population has been recruited to terminal differentiation by 48 to 60 hr. Commitment is associated with persistent HMBA-mediated suppression of c-myb gene expression. By 36 to 48 hr, transcription of the globin genes has increased by 10 to 30 fold, whereas transcription of rRNA genes is suppressed. The steroid, dexamethasone, and the tumor promotor, phorbol-12-myristate-13-acetate, suppress HMBA-induced MEL cell terminal differentiation. The evidence indicates that these agents act at a late step during the latent period. Recently, we showed that MELC variants selected for resistance to vincristine have a marked increased sensitivity to HMBA. Compared to the parental MELC strains, vincristine resistant MELC are: A) responsive to 1/5 to 1/10 the concentration of HMBA; B) induced to terminal differentiation without a latent period and C) resistant to inhibition of HMBA induced terminal differentiation by dexamethasone or tumor promotor. The vincristine resistant MELC have characteristics of the multidrug resistant phenotype. A number of independently derived vincristine resistant MELC lines show similar altered response to HMBA. These findings suggest that vincristine resistance leads to a constitutive expression of a factor or factors induced by HMBA in vincristine sensitive (wild type) MELC during the latent period and which are essential to the transition to terminal differentiation. PMID: 2616574 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1148: Princess Takamatsu Symp. 1989;20:3-13. The evidence for human tumor suppressor genes. Stanbridge EJ. Department of Microbiology and Molecular Genetics, University of California, Irvine 92717. The evidence for human tumor suppressor genes is reviewed. Initial evidence was provided by somatic cell hybridization, where somatic cell hybrids derived from the fusion of malignant and normal parental cells were found to be transformed but nontumorigenic. Tumorigenic segregants appeared at later intervals and were associated with the loss of specific normal chromosomes. Evidence for loss of tumor suppressor genes in many human malignancies was provided by a combination of cytogenetic and restriction fragment length polymorphism analyses. Functional analyses, using monochromosome transfer from normal cells into cancer cells, have confirmed the existence of suppressor genes and their critical role in control of tumor formation. Recently, the tumor suppressor gene Rb-1 has been cloned and also shown to have tumor-suppressing properties. Most recently, a candidate tumor suppressor gene on chromosome 17 (p53) has been implicated in colorectal carcinomas and other human malignancies. It is of interest to note that this gene was originally described as an oncogene. The biological mechanism of tumor suppression has been linked to the induction of differentiation in both somatic cell hybrids and osteosarcoma cells transfected with the normal Rb-1 gene. However, recent studies with monochromosome transfer into neuroblastoma cells indicates that differentiation may be dissociated from tumor suppression. Tumor suppressor genes do not act directly as negative regulators of conventional "dominantly-acting" oncogenes and therefore cannot be considered as anti-oncogenes in the sense of directly interacting with and regulating the expression of such oncogenes as ras and myc. However, it is speculated that they may negatively regulate an, as yet undiscovered, family of oncogenes which would not be dominantly expressed. Publication Types: Review Review, Tutorial PMID: 2577336 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1149: Acta Derm Venereol Suppl (Stockh). 1989;146:33-5. P53 and oncogenes expression in psoriasis. Tadini G, Cerri A, Crosti L, Cattoretti G, Berti E. 1st Department of Dermatology, University of Milan, Italy. Activity of p53, H-ras, c-myc and c-fos in psoriatic lesions was studied using monoclonal antibodies (MoAbs) performing a sensitive immunohistochemical method on frozen sections. Normal skin from surgery was used as control. Reactivity of p53, H-ras and c-myc is remarkable in psoriatic plaques but, in contrast, c-fos expression does not show differences compared to control skin. These findings led us to speculate about the importance of cellular oncogenes in the pathogenesis of psoriasis. PMID: 2532848 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1150: Oncogene. 1988 Nov;3(5):509-15. Cloning of the p53-dependent origin of cellular DNA replication. Iguchi-Ariga SM, Okazaki T, Itani T, Ariga H. Institute of Medical Science, University of Tokyo, Japan. We have recently reported that the c-myc protein may promote cellular DNA replication by binding to the origin of DNA replication (ori) and that an origin of human DNA replication which can autonomously replicate in human cells was cloned as a binding sequence of c-myc protein (Iguchi-Ariga et al., 1987). Here we report that cellular tumor antigen p53 may also participate in cellular DNA replication and another origin of DNA replication was cloned as a possible p53-binding sequence. The sequence could autonomously replicate in Raji cells which express p53 at a high level but not in HL-60 cells in which the coding gene for p53 is largely deleted. Little homology of the sequences was found between c-myc protein-binding ori and p53-binding ori. This suggests that c-myc protein and p53 may independently recognize different ori in chromosomal DNA. PMID: 2978868 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1151: Exp Cell Res. 1988 Oct;178(2):185-98. Transcriptional and post-transcriptional regulation of c-myc, c-myb, and p53 during proliferation and differentiation of murine erythroleukemia cells treated with DFMO and DMSO. Klinken SP, Holmes KL, Morse HC 3rd, Thorgeirsson SS. Laboratory of Immunopathology, NIH, Bethesda, Maryland 20892. The proto-oncogenes myc, myb, and p53 produce nuclear proteins which have been implicated in the regulation of proliferation or differentiation in a number of systems. The expression of these proto-oncogenes was studied in murine erythroleukemia (MEL) cells during (i) normal replication, (ii) DMSO-induced differentiation and (iii), alpha-difluoromethylornithine (DFMO)-restricted cell division and differentiation. The RNA levels of c-myc, c-myb, and p53 were all elevated during normal cellular proliferation; only c-myc expression declined when the cells stopped dividing although the rate of transcription for the gene was unaltered. In contrast, treatment of the cells with DFMO resulted in gradual cessation of cell replication and a decrease in transcription of c-myc, c-myb and p53. When the MEL cells were induced to differentiate with dimethyl sulfoxide (DMSO), a transient reduction in c-myc and c-myb RNA levels occurred immediately prior to the G1 arrest with a concomitant decrease in transcriptional activity, while p53 mRNA production was elevated without an increase in transcription. Similar changes of the proto-oncogene levels were observed when the MEL cells were incubated with DFMO and then later induced with DMSO, a protocol which restricts differentiation of the MEL cells. From these experiments we conclude that (i) c-myc, c-myb, and p53 are regulated independently at both the transcriptional and post-transcriptional levels, (ii) DFMO inhibits MEL cell proliferation and expression of several genes, including c-myc, c-myb and p53, and (iii) DFMO suppresses terminal differentiation but is unable to alter proto-oncogene changes associated with the early stages of differentiation. PMID: 2458948 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1152: Shi Yan Sheng Wu Xue Bao. 1988 Sep;21(3):311-9. [Relationship between expression of c-myc and P53 genes and terminal differentiation during induced differentiation in Friend erythroleukemia cells] [Article in Chinese] Liu HT, Zhang HQ, Xue SB, Du CY, You JS, Song PG, Wang XL, Chen RX. PMID: 3066081 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1153: Eur J Cancer Clin Oncol. 1988 Aug;24(8):1321-8. Nuclear oncogene amplification or rearrangement is not involved in human colorectal malignancies. Dolcetti R, De Re V, Viel A, Pistello M, Tavian M, Boiocchi M. Centro di Riferimento Oncologico, Aviano (Pordenone), Italy. We have examined 44 cases of human colonic and rectal carcinomas for structural rearrangement and amplification of c-myc, N-myc, L-myc, c-myb and p53 oncogenes. DNA hybridization showed evidence of c-myc amplification in only one of the samples tested. In addition, the same tumour also showed a rearrangement immediately 3' to the c-myc locus. No rearrangement could be found at the c-myc locus in the other 43 cases. Moreover, our molecular analysis of N-myc, L-myc, c-myb and p53 genes indicated no relevant alteration of the copy number and/or genomic structure of these nuclear oncogenes. Thus, at least in human colorectal malignancies, it is unlikely that nuclear oncogene structural alterations and/or amplification plays a major role in tumour induction or progression. PMID: 3181252 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1154: Int J Cell Cloning. 1988 Jul;6(4):230-40. Hexamethylene bisacetamide-induced differentiation of transformed cells: molecular and cellular effects and therapeutic application. Marks PA, Rifkind RA. DeWitt Wallace Research, Memorial Sloan-Kettering Cancer Center, New York, New York 10021. Hexamethylene bisacetamide (HMBA), a highly polar compound, induces murine erythroleukemia (MEL) cells to express the erythroid phenotype, including cessation of proliferation. Inducer-mediated differentiation of MEL (DS19) cells is a multistep process characterized by a latent period during which a number of changes occur including alterations in ion flux, an increase in membrane-bound protein kinase C (PKC) activity, the appearance of Ca2+ and phospholipid-independent PKC activity in the cytosol, and modulation in expression of a number of genes such as c-myc, c-myb, c-fos and the p53 genes. HMBA-mediated commitment to terminal differentiation is first detected at about 12 hours and increases in a stochastic fashion until over 95% of the population is recruited to terminal differentiation by 48 to 60 hours. Commitment is associated with persistent suppression of c-myb gene expression. By 36 to 48 hours, transcription of the globin genes has increased 10 to 30 fold, whereas transcription from rRNA genes is suppressed. The steroid, dexamethasone, or the tumor promoter, phorbol-12-myristate-13-acetate (TPA), suppress HMBA-induced MEL cell terminal differentiation. These agents appear to act at a late step during the latent period. MEL cell lines derived from DS19 by selection for resistance to vincristine are: 1) induced to commit without a detectable latent period, 2) markedly more sensitive to HMBA, and 3) resistant to dexamethasone or TPA inhibition of HMBA-induced commitment. The data suggests that vincristine-resistant MEL cells express a factor which circumvents essential HMBA-mediated early events. In vitro studies with HMBA provide a basis for the application of HMBA to clinical therapy of human cancers. Clinical trials with HMBA have been initiated. Publication Types: Review Review, Tutorial PMID: 3047266 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1155: Anticancer Res. 1988 Jan-Feb;8(1):1-7. Oncogene expression in adenocarcinomas of the colon and in colon tumor-derived cell lines. Untawale S, Blick M. Department of Genetics, University of Texas, M.D. Anderson Hospital and Tumor Institute, Houston 77030. Six colon cancer cell lines, 13 colon tumors and ten normal colon tissues were analyzed for RNA expression using probes for c-myc, c-k-ras, c-myb, and c-fos and for the p53, TGF-alpha, and EGF receptor genes. No aberrant transcripts were detected. Levels of expression in tumors ranged from two-fold below that of normal tissue when the v-fos probe was used to 10 fold above the normal level when the c-myc probe was used. Enhanced c-myc expression was also observed in the cell lines. Southern and DNA dot blot analyses revealed c-myc amplification in three of the six cell lines. PMID: 3282475 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1156: Oncogene Res. 1988;3(3):223-38. Molecular analysis of sodium butyrate-induced growth arrest. Toscani A, Soprano DR, Soprano KJ. Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140. Sodium butyrate has been shown to exert dramatic effects on the growth of cells in culture. It inhibits DNA synthesis, arrests actively proliferating cells in G1 and induces differentiation. The mechanism responsible for these various anti-proliferative effects is presently unknown. We wished to study the effects of sodium butyrate on cell growth at the molecular level, by analyzing the pattern of expression exhibited by several growth-associated genes (e.g., c-fos, c-myc, p53 and thymidine kinase) in Swiss 3T3 cells following treatment with sodium butyrate. Our results suggest that sodium butyrate-induced growth arrest of Swiss 3T3 cells (1) can be distinguished at a molecular level from the arrest brought about by other means of growth arrest; (2) does not result from a generalized mechanism which non-specifically shuts down the expression of growth-associated genes but rather occurs via a more specific mechanism which leads to the reduction in the expression of certain genes (e.g., c-myc, p53, thymidine kinase) while inducing the expression of others (e.g., c-fos, aP2); and (3) may involve one or more of the molecular events leading to adipocyte differentiation. PMID: 3144695 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1157: C R Acad Sci III. 1988;306(2):35-8. [Lack of expression of the protein p53 gene in a human T-cell leukemia line] [Article in French] Soudon J, Vilarem MJ, de Fromentel CC, Gras MP, Larsen CJ. I.N.S.E.R.M., Institut de Recherches sur les Maladies du sang, Hopital Saint-Louis, Paris. Expression of the gene encoding the nuclear phosphoprotein p53 (a proto-oncogene classified in the same functional family as c-myc and E1a adenovirus gene) was examined in a human T-cell leukemia (KE-37R cell line). No p53 (or a modified product) could be detected by immunoprecipitation with monoclonal antibodies P Ab 421 and P Ab 122 in KE-37R cell extracts, and no p53-specific RNA was characterized by Northern blot analysis. Southern blot using a murine p53 cDNA clone as a probe, did not reveal any gross rearrangement in the structure of the gene. However, this molecular probe was not suited for investigating the 5' end of the gene which contains the promoter and the non coding exon 1. It is interesting to notice that in KE-37R cells, c-myc has been activated by a t(8; 14) (q24; q11) translocation, suggesting that the c-myc product might substitute to some functions normally requiring p53. PMID: 3126985 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1158: Exp Cell Res. 1987 Apr;169(2):554-9. Comparative analysis of the involvement of p53, c-myc and c-fos in epidermal growth factor-mediated signal transduction. Filmus J, Benchimol S, Buick RN. p53, a transformation-related protein located in the nucleus, shares several properties with the product of the nuclear proto-oncogene c-myc. The latter is transiently induced after different membrane-originating stimuli. A similar observation has been made with c-fos, a gene that also belongs to the 'nuclear' class of oncogenes. Here we show that p53, unlike the products of the c-myc and c-fos genes, is not induced by the signal generated by the interaction between epidermal growth factor (EGF) and its receptor. Hence, p53 does not appear to be involved in EGF signal transduction. In order to draw this conclusion we have used an EGF receptor gene-amplified human breast tumor cell line that is growth-inhibited by EGF, and exponentially growing normal human fibroblasts. PMID: 2435565 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1159: Prog Clin Biol Res. 1987;251:253-68. Changes in gene expression during hexamethylene bisacetamide induced erythroleukemia differentiation. Marks PA, Ramsay R, Sheffery M, Rifkind RA. DeWitt Wallace Research Laboratories, Memorial Sloan-Kettering Cancer Center, New York, New York. HMBA induces MELC to terminal erythroid differentiation. The mechanism of HMBA action is not known. Culture with HMBA causes changes in gene expression which occur during the early "latent period", that is, prior to commitment to terminal differentiation. The inducer causes a decrease in diacylglycerol concentration, a decrease in Ca+2 and a decrease in phospholipid-dependent protein kinase C activity (within 2 hr) (Figure 2). There is an early suppression (within 1-2 hrs) of c-myb and c-myc gene transcription and an increase in c-fos mRNA (within 4 hrs). HMBA-induced commitment to terminal differentiation is detected by 12 hrs and over 95% become committed cells by 48 to 60 hrs. Commitment is associated with persistent suppression of c-myb gene transcription and elevated levels of c-fos mRNA whereas the level of c-myc mRNA returns to that of uninduced cells. By 36 to 48 hrs, transcription of alpha 1 and beta maj globin genes is increased 10 to 30 fold, while that of rRNA genes is suppressed. It is not yet clear how the protein products of proto-oncogenes elicit or modify cellular responses. Changes in expression of c-myb, c-myc, c-fos and p53 genes which occur during HMBA-induced differentiation, as well as in several other systems, suggest that products of these genes may have a role in regulating expression of multiple genes. One possible application of the established pattern of HMBA-induced modulation of gene expression during MELC differentiation may be in following the effects of cyto-differentiation agents during treatment of cancers. Phase I and Phase II chemical trials have been initiated to evaluate HMBA as a cytodifferentiation agent in human neoplasms (65). For most human tumors, assay for cytologic evidence of induced differentiation is difficult at best. Following the effects of a differentiation inducing agent by determining c-myc, or c-myb, mRNA levels may provide useful indicators of biological activity of HMBA and be a basis for evaluating whether continued administration of the agent is of interest in terms of potential clinical efficacy.(ABSTRACT TRUNCATED AT 400 WORDS) PMID: 3481077 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1160: Ann N Y Acad Sci. 1987;511:246-55. Induction of transformed cells to terminal differentiation. Marks PA, Sheffery M, Ramsay R, Ikeda K, Rifkind RA. DeWitt Wallace Research Laboratories, Memorial Sloan-Kettering Cancer Center, New York, New York. HMBA induces MEL cells to terminal erythroid differentiation. HMBA causes a decrease in diacylglycerol concentration, a decrease in Ca+2 and phospholipid-dependent protein kinase C activity (within 2 hr). There is an early (within 1-2 hrs) suppression of c-myb and c-myc gene transcription and an increase in c-fos mRNA (within 4 hrs). During the early or "latent" period there is no detectable commitment of MELC to terminal cell division or expression of differentiated genes such as alpha 1 or beta maj globin genes. HMBA-induced commitment to terminal differentiation is detected by 12 hrs and over 95% become committed cells by 48-60 hrs. Commitment is associated with persistent suppression of c-myb gene transcription and elevated levels of c-fos mRNA, whereas the level of c-myc mRNA returns to that of uninduced cells. By 36-48 hrs, transcription of the alpha 1 and beta maj globin genes increases 10-30 fold, and that of rRNA genes is suppressed. Changes in expression of c-myb, c-myc, c-fos and p53 genes that occur early during HMBA-induced differentiation may be important in the multistep process involved in commitment of MEL cells to terminal differentiation. Continued suppression of c-myb gene expression may be required for terminal differentiation of these cells. Publication Types: Review Review, Tutorial PMID: 3326466 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1161: Mol Cell Biol. 1986 Dec;6(12):4379-86. Neoplastic transformation of rat 3Y1 cells by a transcriptionally activated human c-myc gene and stabilization of p53 cellular tumor antigen in the transformed cells. Shiroki K, Segawa K, Koita Y, Shibuya M. Transformed foci were obtained in rat 3Y1 fibroblasts cotransfected with pRmyc 27 (transcriptionally activated c-myc) and pSV2neo DNA. RmycY cell lines (1 to 7) were established from these foci. RmycY cells were small and round and contained enlarged nucleoli in the nucleus. The myc gene was expressed in these cell lines at a much higher level than in 3Y1 cells and at a level similar to that in HL-60 cells. These cell lines formed colonies in soft-agar culture and tumors in syngeneic rats transplanted with RmycY cells. Expression of the gene and colony formation in soft-agar culture were analyzed in subclones from RmycY cell line 1. A correlation between myc gene expression and the ability to form colonies in soft-agar culture was observed in these cells. Antibody against p53 cellular tumor antigen was detected in some sera from tumor-bearing rats. p53 cellular tumor antigen stabilized and accumulated in RmycY cells to the same extent as in simian virus 40-transformed cells. The results suggest that elevated c-myc expression and an increased amount of p53 cause 3Y1 cells to become a more tumorigenic cell line. PMID: 3025654 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1162: Mol Cell Biol. 1986 Jan;6(1):7-14. Tumorigenicity of fibroblast lines expressing the adenovirus E1a, cellular p53, or normal c-myc genes. Kelekar A, Cole MD. Cellular and viral oncogenes have been linked to the transformation of established cell lines in vitro, to the induction of tumors in vivo, and to the partial transformation or immortalization of primary cells. Based on the ability to cooperate with mutated ras oncogenes in the transformation of primary cells, the adenovirus E1a and cellular p53 genes have been assigned an immortalizing activity. It is demonstrated in this paper that the adenovirus type 5 E1a gene and simian virus 40 promoter-linked p53 cDNA are able to transform previously immortalized cells to a tumorigenic phenotype without a significant change in cell morphology. It is also shown that, when linked to a constitutive promoter, the normal mouse and human c-myc genes have the same transforming activity. Cells transformed by each of these oncogenes have an increased capacity to grow in the absence of growth factors and a limited anchorage-independent growth capability. PMID: 2946931 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1163: Nature. 1985 Oct 17-23;317(6038):636-9. Post-transcriptional control of myc and p53 expression during differentiation of the embryonal carcinoma cell line F9. Dony C, Kessel M, Gruss P. Teratocarcinoma cells provide us with a model system for the study of differentiation and development. One of the best characterized cell lines, the embryonal carcinoma stem cell line F9, differentiates after treatment with retinoic acid (RA) and dibutyryl cyclic AMP into parietal endoderm. This differentiation process is accompanied by the induction of several genes, for example, those encoding collagen IV, plasminogen activator and intermediate filaments like laminin. In contrast, a marked reduction of stable messenger RNA has been observed for the gene encoding p53 and for c-myc. Both cellular oncogenes seem to be involved in the regulation of cellular proliferation and neoplastic transformation. For growth-arrested 3T3 fibroblasts, growth-factor-induced changes of myc RNA are controlled at the level of transcription. In contrast, F9 cells provide a differentiation system in which cells are able to change from a tumorigenic state into non-dividing, non-tumorigenic endodermal cells. The latter process enabled us to study the regulation of myc and p53 genes in the same cells at different stages of growth, tumorigenicity and differentiation. Here we report that down-regulation of stable myc and p53 RNA during irreversible differentiation of F9 cells occurs at the post-transcriptional level. Using an in vitro nuclear transcription assay, we found that the polymerase II density on both genes remains constant during differentiation. In agreement with this interpretation, we detected myc RNA as stable transcripts in differentiated F9 cells after treatment of the cells with cycloheximide. The post-transcriptional regulatory mechanisms controlling p53 and myc stability follow different kinetics. Whereas the down-regulation of myc seems to be an early event of F9 differentiation occurring within the first 24 h, the post-transcriptional regulation of p53 occurs at a later stage (two to three days), possibly as a consequence of cell cycle changes. PMID: 2414665 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1164: Proc Natl Acad Sci U S A. 1985 Feb;82(3):790-4. Major deletions in the gene encoding the p53 tumor antigen cause lack of p53 expression in HL-60 cells. Wolf D, Rotter V. The tumor antigen p53 is overproduced in transformed cells of various species, including man. HL-60 is an exceptional human tumor cell line that does not express this protein. Hybridization of polyadenylylated mRNA of these cells with a human p53 cDNA probe (p53-H14), which we cloned, had indicated a total absence of the mature-size (3.0 kilobases) or any aberrant p53 mRNA species. Analysis of the genomic HL-60 DNA indicated that the p53 gene in these cells was significantly altered. Most of the gene was deleted, and the residual p53 sequences of these cells, which show weak homology, mapped to the corresponding 5' region of the p53 gene. In agreement with previously documented results, we found that HL-60 cells have an amplified c-myc gene. We suggest that the deficiency of the p53 protein in HL-60 cells could have been overcome by using an alternative metabolic pathway. The c-myc product is a candidate for such an alternative protein. PMID: 2858093 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1165: Nature. 1984 Dec 13-19;312(5995):651-4. Cellular immortalization by a cDNA clone encoding the transformation-associated phosphoprotein p53. Jenkins JR, Rudge K, Currie GA. Malignant transformation of primary cells requires at least two distinct and characteristic alterations in cellular behaviour. The first, cellular immortality, can be induced by chemical carcinogens or by cloned oncogenes such as polyoma large T (ref. 4), adenovirus early region 1A (E1A) or the oncogene from avian (MC29) myelocytomatosis virus, v-myc. Cells whose in vitro life-span has been extended by these procedures can be fully transformed by transfection with oncogenes belonging to a different complementation group, including genes of the ras family, adenovirus E1b and polyoma virus middle T (refs 4, 5). The unstable cellular phosphoprotein p53 is frequently present at elevated levels in transformed cells and is stabilized by the formation of complexes with simian virus 40 (SV40) large T or adenovirus E1b 57K protein. Although several reports have associated p53 with cell proliferation, its role remains obscure. We have cloned complementary DNA sequences encoding murine p53 and report here that transfection of p53 expression constructs into cells of finite lifespan in vitro results in cellular immortality and susceptibility to transformation by a ras oncogene. PMID: 6095117 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 1166: EMBO J. 1984 Sep;3(9):2179-83. Analysis of the gene coding for the murine cellular tumour antigen p53. Bienz B, Zakut-Houri R, Givol D, Oren M. A genomic clone containing the functional gene for the murine p53 cellular tumour antigen was isolated and structurally characterised. The gene contains at least 11 exons and 10 introns, the first intron possessing a length of 6.1 kb. Attempts to determine the exact 5' end of p53 mRNA were inconclusive, probably due to the presence of a remarkable stem and loop structure (delta G degrees approximately equal to -56 kcal/mol) in the 5' region of the gene. Suggestive similarities were found to exist between p53 and the protein product of the myc oncogene. PMID: 6092064 [PubMed - indexed for MEDLINE] ---------------------------------------------------------------