1: Chemotherapy. 2005 Oct;51(6):319-23. Epub 2005 Oct 13. Effect of the farnesyl transferase inhibitor L-744,832 on the colon cancer cell line DLD-1 and its combined use with radiation and 5-FU. Kavgaci H, Ozdemir F, Ovali E, Yavuz A, Yavuz M, Aydin F. Department of Medical Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. hkavgaci@meds.ktu.edu.tr BACKGROUND: Ras oncogenes are found in 25% of human tumors and they significantly affect prognosis. One of the major fields studied to improve anticancer drugs is blockade of the oncogenic ras protein function. One of the mechanisms to block the function of these proteins is to block farnesylation using a farnesyl transferase inhibitor (FTI) and thus to prevent the ras from anchoring to the cell membrane. METHODS: In this study, we investigated the effects of FTI L-744,832 either alone or in combination with 5-fluorouracil (5-FU; 1 microM/l) and radiotherapy (2, 6, and 10 Gy) on the colon cancer cell line DLD-1 with mutations in K-, N- and H-ras, c-myb, c-myc, p53, fos, sis and DNA repair genes. Drugs were added 3 h after cultivation. Radiotherapy was performed on the 3rd day of the study. On the 3rd day, medium and drugs were changed. Evaluations were performed on the 6th day. RESULTS: Administration of L-744,832, neither alone nor its combination with 5-FU and radiation, affected the number of DLD-1 cells and apoptosis rates. Regarding its effects on the cell cycle, L-744,832 was shown to lead to G(0)/G(1) and G(2)/M accumulation in a dose-dependent manner when administered alone. However, in combination with 5-FU, only a G(0)/G(1) accumulation was observed. CONCLUSION: Our study showed that FTI L-744,832 does not effect the cell number and apoptosis rate of DLD-1 cells and it cannot overcome 5-FU and radiation resistance, although it is able to modify some phases of the cell cycle. Copyright 2005 S. Karger AG, Basel. PMID: 16224182 [PubMed - in process] --------------------------------------------------------------- 2: Leukemia. 2005 Nov;19(11):1958-68. Effects of overexpression of HBP1 upon growth and differentiation of leukemic myeloid cells. Yao CJ, Works K, Romagnoli PA, Austin GE. Department of Pathology and Laboratory Medicine, Veterans Affairs Medical Center, Decatur, GA 30033, USA. HMG-box containing protein 1 (HBP1) is a member of the high mobility group (HMG) of chromosomal proteins. Since HBP1 exhibits tumor-suppressor activity in nonmyeloid tissues, we examined the effects of ectopic overexpression of HBP1 upon the growth and differentiation of myeloid cells. We prepared transient and stable transfectants of the myeloblast cell line K562, which overexpress HBP1 mRNA and protein. HBP1 transfectants displayed slower growth in cell culture and reduced colony formation in soft agar, retardation of S-phase progression, reduced expression of cyclin D1 and D3 mRNAs and increased expression of p21 mRNA. HBP1 transfectants also underwent increased apoptosis, as demonstrated by morphology and binding of Annexin V. Fas ligand mRNA levels were increased in HBP1 transfectants, suggesting involvement of the Fas/Fas ligand pathway. HBP1 overexpression enhanced differentiation of K562 cells towards erythroid and megakaryocyte lineages, as evidenced by increased hemoglobin and CD41a expression. Overexpression of HBP1 modulated mRNA levels for myeloid-specific transcription factors C/EBPalpha, c-Myb, c-Myc, and JunB, as well as lineage-specific transcription factors PU.1, GATA-1, and RUNX1. These findings suggest that in myeloid cells HBP1 may serve as a tumor suppressor and a general differentiation inducer and may synergize with chemical differentiating agents to enhance lineage-specific differentiation. PMID: 16179914 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 3: Plant J. 2005 Oct;44(1):62-75. Metabolic engineering of proanthocyanidins by ectopic expression of transcription factors in Arabidopsis thaliana. Sharma SB, Dixon RA. Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA. Genetic transformation of Arabidopsis thaliana with the Arabidopsis TT2 MYB transcription factor resulted in ectopic expression of the BANYULS gene, encoding anthocyanidin reductase, AHA10 encoding a P-type proton-pump and TT12 encoding a transporter involved in proanthocyanidin biosynthesis. When coupled with constitutive expression of PAP1, a positive regulator of anthocyanin biosynthesis, TT2 expression in Arabidopsis led to accumulation of proanthocyanidins, but only in a subset of cells in which the BANYULS promoter is naturally expressed. Ectopic expression of the maize Lc MYC transcription factor weakly induced AHA10 but did not induce BANYULS, TT12 or accumulation of proanthocyanidins. However, high-level combined expression of TT2, PAP1 and Lc resulted in proanthocyanidin synthesis throughout young leaves and cotyledons, followed by death of the plants 1 to 2 weeks after germination. We discuss these results in relation to engineering proanthocyanidins to improve the quality of food and forage plants. PMID: 16167896 [PubMed - in process] --------------------------------------------------------------- 4: Sheng Wu Gong Cheng Xue Bao. 2004 Jan;20(1):30-3. [Cloning and expression of hTRF1 in Escherichia coli and preparation of polyclonal antibody] [Article in Chinese] Jiang H, Zheng XF, Luo Y, Zhu J, Fu HJ, Sun QL, Chen CH, Sun ZX. Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China. Human telomeric repeat binding factor 1(TRF1) contains one Myb-type DNA-binding repeat and an amino-terminal acidic domain. It can bind to the duplex array of TTAGGG repeats at chromosome ends and is shown to be important in preserving genomic stability, maintaining cell proliferative capacity, and blocking the activation of DNA-damage cell cycle checkpoints. Interestingly, the double strand DNA breaks sensor ATM interacts with and phosphorylates Pin2/TRF1 and inhibits its function after DNA damage. Are there some proteins else that can interact with TRF1 and influence its function? In order to analysis the interaction between TRF1 and other proteins, we must prepare the antiserum that can recognize the endogenous TRF1 of cell lysates. TRF1 cDNA was amplified using cDNA Library of HeLa cell by PCR and cloned into pUCm-T vector. Sequence analysis reveals identity to the GenBank report. The TRF1 cDNA was subcloned into expression vector pET-28c(+) and expressed in E. coli as a fusion protein of 65 kD. The recombinant TRF1 can express in the supernatant (about 12.3% in total protein) on the induction of 0.5 mmol/L IPTG at 37 degrees C for 3 hours. Western-blot analysis showed the recombinant protein can react with TRF1 polyclonal antibody sc-6165 (from Santa Cruz Company). His6-TRF1 was purified by Ni(2+) -NTA resin affinity chromatography made by ourselves and showed to be homogeneity in SDS-PAGE. Rabbits were immunized for four times to prepare polyclonal antibody. The unpurified antiserum can recognize the overexpressed TRF1 with myc-tag and the endogenous Pin2/TRF1 of cell lysate by Western-blot at 1:1000 dilution. At 1:400 dilution, the antiserum can interact with endogenous TRF1 by Immunofluorescence cell staining analysis. The endogenous TRF1 in different cell lines, such as HepG2, 803, MCF7 and HeLa, locates in the nucleus. The soluble expression TRF1 and preparation of its antibody lay the foundation to study it further. PMID: 16108485 [PubMed - in process] --------------------------------------------------------------- 5: Dermatology. 2005;211(2):84-92. Overexpression of c-myb in leukaemic and non-leukaemic variants of cutaneous T-cell lymphoma. Poenitz N, Simon-Ackermann J, Gratchev A, Qadoumi M, Klemke CD, Stadler R, Kremer A, Radenhausen M, Henke U, Assaf C, Utikal J, Goerdt S, Dippel E. Department of Dermatology, Venereology and Allergology, University Medical Centre Mannheim, Ruprecht Karl University of Heidelberg, Mannheim, Germany. nina.poenitz@haut.ma.uni-heidelberg.de BACKGROUND: The c-myb oncogene is a transcription factor that regulates proliferation, differentiation and apoptosis of haematopoietic cells and activated T cells by binding to promoter sequences of such genes as c-myc or bcl-2 that are expressed in cutaneous T-cell lymphoma (CTCL). OBJECTIVE: Our study was performed in order to evaluate c-myb expression as a quantitative parameter for differential diagnosis in leukaemic and non-leukaemic variants of CTCL. METHODS: c-myb expression was analysed in lesional skin and in the peripheral blood of 21 patients with mycosis fungoides (MF), 15 patients with Sezary syndrome (SS) and 15 patients with inflammatory skin diseases using immunohistochemistry and semiquantitative as well as quantitative RT-PCR. RESULTS: Immunohistochemistry confirmed expression of c-myb in the lesional skin of the majority of CTCL patients with a tendency towards higher expression in SS (1.86 +/- 0.5) versus MF (1.2 +/- 0.7) while c-myb was absent from the lesional skin of patients with inflammatory skin diseases. c-myb was overexpressed in the peripheral blood in all SS patients (100% SS vs. 35.7% MF) at a high expression level (51,335.31 +/- 31,960.32 AU in SS vs. 1,226.35 +/- 1,258.29 AU in MF using semiquantitative RT-PCR, and 5.72 x 10(-2) +/- 2.27 x 10(-2) in SS vs. 0.91 x 10(-2) +/- 1.18 x 10(-2) in MF vs. 0.24 x 10(-2) +/- 0.11 x 10(-2) in inflammatory skin disease using quantitative RT-PCR). CD4+ cells from the peripheral blood of SS patients and cell lines in vitro showed the highest c-myb expression levels upon quantitative RT-PCR (23.27 x 10(-2) and 10.78 x 10(-2) +/- 7.24 x 10(-2)). CONCLUSION: Overexpression of c-myb in skin lesions of both non-leukaemic and leukaemic CTCL independent of the stage of the disease indicates that it acts early in disease development. Nevertheless, if positive, c-myb expression in lesional skin is a clear-cut diagnostic marker for CTCL as compared to inflammatory skin diseases. High-level expression of c-myb in the peripheral blood as assessed by quantitative RT-PCR constitutes an additional diagnostic parameter for SS and may be especially useful in cases in which morphological determination of Sezary cells or FACS analysis of CD7 and CD26 remain inconclusive. (c) 2005 S. Karger AG, Basel PMID: 16088151 [PubMed - in process] --------------------------------------------------------------- 6: Mol Cell Neurosci. 2005 Sep;30(1):90-107. Transcriptional changes during neuronal death and replacement in the olfactory epithelium. Shetty RS, Bose SC, Nickell MD, McIntyre JC, Hardin DH, Harris AM, McClintock TS. Department of Physiology, Cellular and Molecular Neuroscience of Sensory Systems Training Program, University of Kentucky, 800 Rose Street, Lexington, KY 40536-0298, USA. The olfactory epithelium has the unusual ability to replace its neurons. We forced replacement of mouse olfactory sensory neurons by bulbectomy. Microarray, bioinformatics, and in situ hybridization techniques detected a rapid shift in favor of pro-apoptotic proteins, a progressive immune response by macrophages and dendritic cells, and identified or predicted 439 mRNAs enriched in olfactory sensory neurons, including gene silencing factors and sperm flagellar proteins. Transcripts encoding cell cycle regulators, axonogenesis proteins, and transcription factors and signaling proteins that promote proliferation and differentiation were increased at 5--7 days after bulbectomy and were expressed by basal progenitor cells or immature neurons. The transcription factors included Nhlh 1, Hes 6, Lmyc 1, c-Myc, Mxd 4, Id 1, Nmyc 1, Cited 2, c-Myb, Mybl 1, Tead 2, Dp 1, Gata 2, Lmo 1, and Sox1 1. The data reveal significant similarities with embryonic neurogenesis and make several mechanistic predictions, including the roles of the transcription factors in the olfactory sensory neuron lineage. PMID: 16027002 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 7: Prostate. 2005 Jun 1;63(4):369-84. Unopposed c-MYC expression in benign prostatic epithelium causes a cancer phenotype. Williams K, Fernandez S, Stien X, Ishii K, Love HD, Lau YF, Roberts RL, Hayward SW. Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37212-2765, USA. karin.williams@vanderbilt.edu BACKGROUND: We have sought to develop a new in vivo model of prostate carcinogenesis using human prostatic epithelial cell cultures. Human prostate cancers frequently display DNA amplification in the 8q24 amplicon, which leads to an increase in the copy number of the c-MYC gene, a finding that suggests a role for c-MYC in human prostate carcinogenesis. In addition overexpression of c-MYC in transgenic mouse models results in prostatic carcinogenesis. METHODS: We took advantage of the ability of retroviruses to integrate foreign DNA into human prostatic epithelium (huPrE) to generate cell lines that overexpress the c-MYC protooncogene. These cells were recombined with inductive rat urogenital sinus mesenchyme and grafted beneath the renal capsule of immunocompromised rodent hosts. RESULTS: The resultant tissue displayed a phenotype consistent with a poorly differentiated human prostatic adenocarcinoma. The tumors were rapidly growing with a high proliferative index. The neoplastic cells in the tumor expressed both androgen receptors (AR) and prostate-specific antigen (PSA), both characteristic markers of human prostate cancers. Microarray analysis of human prostatic epithelial cells overexpression c-MYC identified a large number of differentially expressed genes some of which have been suggested to characterize a subset of human cancers that have myc overexpression. Specific examples were confirmed by Western blot analysis and include upregulation of c-Myb and decreased expression of PTEN. Control grafts using either uninfected huPrE or using huPrE cells infected using an empty vector expressing a green fluorescent protein tag gave rise to well differentiated benign prostatic glandular ducts. CONCLUSIONS: By using a retroviral infection strategy followed by tissue recombination we have created a model of human prostate cancer that demonstrates that the c-MYC gene is sufficient to induce carcinogenesis. Copyright 2004 Wiley-Liss, Inc. PMID: 15937962 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 8: Gene. 2005 May 23;351:171-80. Regulation of the cyclin D1 and cyclin A1 promoters by B-Myb is mediated by Sp1 binding sites. Bartusel T, Schubert S, Klempnauer KH. Institut fur Biochemie, Westfalische-Wilhelms-Universitat Munster, Germany. B-Myb is a highly conserved member of the Myb family of transcription factors which plays an important role during the cell cycle. Previous work has shown that B-Myb is phosphorylated at several sites by cyclin A/Cdk2 in the early S-phase. These phosphorylations increase the transactivation potential of B-Myb by counteracting the repressive function of an inhibitory domain located at the carboxyl-terminus of B-Myb. As yet, only a few genes have been identified as B-Myb target genes. Previous work has suggested that the cyclin D1 gene might be regulated by B-Myb. Here, we have studied the effect of B-Myb on the promoter of the cyclin D1 gene. We show that B-Myb is a potent activator of the cyclin D1 promoter and that this activation is not mediated by Myb binding sites but rather by a group of Sp1 binding sites which have previously been shown to be crucial for cyclin D1 promoter activity. Our data show that the C-terminal domain of B-Myb is required for the activation of the cyclin D1 promoter and that this part of B-Myb interacts with Sp1. Finally, we have found that the promoter of the cyclin A1 gene is also activated by B-Myb by a Sp1 binding site-dependent mechanism. The effect of B-Myb on the promoters of the cyclin A1 and D1 genes is reminiscent of the mechanism that has been proposed for the autoregulation of the B-myb promoter by B-Myb, which also involves Sp1 binding sites. Taken together, our identification of two novel B-Myb responsive promoters whose activation by B-Myb does not involve Myb binding sites extends previous evidence for the existence of a distinct mechanism of transactivation by B-Myb which is dependent on Sp1 binding sites. The observation that this mechanism is not subject to the inhibitory effect of the C-terminal domain of B-Myb but rather requires this domain supports the notion that the Sp1 site-dependent mechanism is already active in the G1-phase prior to the phosphorylation of B-Myb by cyclin A/Cdk2. PMID: 15922873 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 9: Mol Hum Reprod. 2005 Jun;11(6):441-50. Epub 2005 May 6. Estrogen-induced changes in IGF-I, Myb family and MAP kinase pathway genes in human uterine leiomyoma and normal uterine smooth muscle cell lines. Swartz CD, Afshari CA, Yu L, Hall KE, Dixon D. Laboratory of Experimental Pathology and Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA. Many studies have implicated numerous hormones, growth factors, cytokines and other signal transduction molecules in the pathogenesis of uterine leiomyoma. Estrogen and estrogen-related genes are thought to play a key role in the growth of uterine leiomyomas, but the molecular mechanisms are unclear. In an attempt to investigate various pathways that might be involved in estrogen-regulated uterine leiomyoma growth as well as to identify any novel effector genes, microarray studies comparing estrogen-treated uterine leiomyoma cells (UtLM) and normal myometrial cells to untreated cells were performed. Several genes were differentially expressed in estrogen treated UtLM cells, including insulin-like growth factor-I (IGF-I) and others potentially involved in the IGF-I signalling pathway, specifically genes for A-myb, a transcription factor which promotes cell cycle progression and for MKP-1, a dual specificity phosphatase that dephosphorylates mitogen-activated protein kinase. IGF-I and A-myb were up-regulated in estrogen-treated cells while MKP-1 was down-regulated. Two other cell cycle promoting genes, c-fos and myc, were also down-regulated in estrogen treated UtLM cells. These genes are typically up-regulated in response to estrogen in some cells, notably breast epithelial cells, yet consistently have lower expression levels in uterine leiomyoma tissue when compared to autologous myometrium. Our results demonstrate some novel genes that may play a role in the growth of uterine leiomyoma, strengthen the case for involvement of the IGF-I pathway in the response of UtLM to estrogen and corroborate evidence that uterine smooth muscle cells respond to estrogen with a different gene expression pattern than that seen in epithelial cells. PMID: 15879465 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 10: Nat Biotechnol. 2005 May;23(5):591-9. Epub 2005 May 1. Gene knockdown by large circular antisense for high-throughput functional genomics. Lee YH, Moon IJ, Hur B, Park JH, Han KH, Uhm SY, Kim YJ, Kang KJ, Park JW, Seu YB, Kim YH, Park JG. WelGENE Inc., 71B 4L, Development Sector 2-3, Sungseo Industrial Park, Dalseogu, Daegu, 704-230, South Korea. Single-stranded genomic DNA of recombinant M13 phages was tested as an antisense molecule and examined for its usefulness in high-throughput functional genomics. cDNA fragments of various genes (TNF-alpha, c-myc, c-myb, cdk2 and cdk4) were independently cloned into phagemid vectors. Using the life cycle of M13 bacteriophages, large circular (LC)-molecules, antisense to their respective genes, were prepared from the culture supernatant of bacterial transformants. LC-antisense molecules exhibited enhanced stability, target specificity and no need for target-site searches. High-throughput functional genomics was then attempted with an LC-antisense library, which was generated by using a phagemid vector that incorporated a unidirectional subtracted cDNA library derived from liver cancer tissue. We identified 56 genes involved in the growth of these cells. These results indicate that an antisense sequence as a part of single-stranded LC-genomic DNA of recombinant M13 phages exhibits effective antisense activity, and may have potential for high-throughput functional genomics. PMID: 15867911 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 11: Cancer Res. 2005 May 1;65(9):3633-42. Disruption of Rb/E2F pathway results in increased cyclooxygenase-2 expression and activity in prostate epithelial cells. Davis JN, McCabe MT, Hayward SW, Park JM, Day ML. Department of Urology, Michigan Urology Center, University of Michigan, Ann Arbor, Michigan 48109-0944, USA. The loss of the retinoblastoma tumor suppressor gene (RB) is common in many human cancers, including prostate. We previously reported that engineered deletion of RB in prostate epithelial cells results in sustained cell growth in serum-free media, a predisposition to develop hyperplasia and dysplasia in prostate tissue recombinant grafts, and sensitization to hormonal carcinogenesis. Examining the molecular consequence of RB loss in this system, we show that cyclooxygenase-2 (COX-2) is significantly up-regulated following RB deletion in prostate tissue recombinants. To study the effect of RB deletion on COX-2 regulation, we generated wild-type (PrE) and Rb-/- (Rb-/-PrE) prostate epithelial cell lines rescued by tissue recombination. We show elevated COX-2 mRNA and protein expression in Rb-/-PrE cell lines with increased prostaglandin synthesis. We also find that loss of Rb leads to deregulated E2F activity, with increased expression of E2F target genes, and that exogenous expression of E2F1 results in elevated COX-2 mRNA and protein levels. COX-2 promoter studies reveal that E2F1 transcriptionally activates COX-2, which is dependent on the transactivation and DNA-binding domains of E2F1. Further analysis revealed that the E2F1 target gene, c-myb, is elevated in Rb-/-PrE cells and E2F1-overexpressing cells, whereas ectopic overexpression of c-myb activates the COX-2 promoter in prostate epithelial cells. Additionally, cotransfection with E2F1 and a dominant-negative c-myb inhibited E2F1 activation of the COX-2 promoter. Taken together, these results suggest activation of a transcriptional cascade by which E2F1 regulates COX-2 expression through the c-myb oncogene. This study reports a novel finding describing that deregulation of the Rb/E2F complex results in increased COX-2 expression and activity. PMID: 15867358 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 12: Blood. 2005 Jul 1;106(1):193-200. Epub 2005 Mar 3. T-cell generation by lymph node resident progenitor cells. Terra R, Louis I, Le Blanc R, Ouellet S, Zuniga-Pflucker JC, Perreault C. Institute of Research in Immunology and Cancer, University of Montreal, QC, Canada. In the thymus, 2 types of Lin-Sca-1+ (lineage-negative stem cell antigen-1-positive) progenitors can generate T-lineage cells: c-Kit(hi) interleukin-7 receptor alpha-negative (c-Kit(hi)IL-7Ralpha-) and c-Kit(lo)IL-7Ralpha+. While c-Kit(hi)IL-7Ralpha- progenitors are absent, c-Kit(lo)IL-7Ralpha+ progenitors are abundant in the lymph nodes (LNs). c-Kit(lo)IL-7Ralpha+ progenitors undergo abortive T-cell commitment in the LNs and become arrested in the G1 phase of the cell cycle because they fail both to up-regulate c-myb, c-myc, and cyclin D2 and to repress junB, p16(INK4a), and p21(Cip1/WAF). As a result, development of LN c-Kit(lo)IL-7Ralpha+ progenitors is blocked at an intermediate CD44+CD25lo development stage in vivo, and LN-derived progenitors fail to generate mature T cells when cultured with OP9-DL1 stromal cells. LN stroma can provide key signals for T-cell development including IL-7, Kit ligand, and Delta-like-1 but lacks Wnt4 and Wnt7b transcripts. LN c-Kit(lo)IL-7Ralpha+ progenitors are able to generate mature T cells when cultured with stromal cells producing wingless-related MMTV integration site 4 (Wnt4) or upon in vivo exposure to oncostatin M whose signaling pathway intersects with Wnt. Thus, supplying Wnt signals to c-Kit(lo)IL-7Ralpha+ progenitors may be sufficient to transform the LN into a primary T-lymphoid organ. These data provide unique insights into the essence of a primary T-lymphoid organ and into how a cryptic extrathymic T-cell development pathway can be amplified. PMID: 15746078 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 13: Proc Natl Acad Sci U S A. 2005 Mar 8;102(10):3697-702. Epub 2005 Feb 28. Identification and functional significance of genes regulated by structurally different histone deacetylase inhibitors. Peart MJ, Smyth GK, van Laar RK, Bowtell DD, Richon VM, Marks PA, Holloway AJ, Johnstone RW. The Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne 3002, Victoria, Australia. Histone deacetylase inhibitors (HDACis) inhibit tumor cell growth and survival, possibly through their ability to regulate the expression of specific proliferative and/or apoptotic genes. However, the HDACi-regulated genes necessary and/or sufficient for their biological effects remain undefined. We demonstrate that the HDACis suberoylanilide hydroxamic acid (SAHA) and depsipeptide regulate a highly overlapping gene set with at least 22% of genes showing altered expression over a 16-h culture period. SAHA and depsipeptide coordinately regulated the expression of several genes within distinct apoptosis and cell cycle pathways. Multiple genes within the Myc, type beta TGF, cyclin/cyclin-dependent kinase, TNF, Bcl-2, and caspase pathways were regulated in a manner that favored induction of apoptosis and decreased cellular proliferation. APAF-1, a gene central to the intrinsic apoptotic pathway, was induced by SAHA and depsipeptide and shown to be important, but not essential, for HDACi-induced cell death. Overexpression of p16(INK4A) and arrest of cells in G(1) can suppress HDACi-mediated apoptosis. Although p16(INK4A) did not affect the genome-wide transcription changes mediated by SAHA, a small number of apoptotic genes, including BCLXL and B-MYB, were differentially regulated in a manner consistent with attenuated HDACi-mediated apoptosis in arrested cells. We demonstrate that different HDACi alter transcription of a large and common set of genes that control diverse molecular pathways important for cell survival and proliferation. The ability of HDACi to target multiple apoptotic and cell proliferation pathways may provide a competitive advantage over other chemotherapeutic agents because suppression/loss of a single pathway may not confer resistance to these agents. PMID: 15738394 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 14: Expert Opin Biol Ther. 2005 Jan;5(1):79-89. Antisense therapy for restenosis following percutaneous coronary intervention. Kipshidze N, Tsapenko M, Iversen P, Burger D. Lenox Hill Hospital, Department of Interventional Cardiac & Vascular Services, 130 East 77th Street, New York, NY 10021, USA. NKipshidze@Lenoxhill.net. Recent advances in vascular gene transfer have shown potential new treatment modalities for cardiovascular disease, particularly in the treatment of vascular restenosis. The antisense approach to inhibiting gene expression involves introducing oligonucleotides complementary to mRNA into cells in order to block any one of the following processes: uncoiling of DNA, transcription of DNA, export of RNA, DNA splicing, RNA stability, or RNA translation involved in the synthesis of proteins in cellular proliferation. The approach includes the use of antisense oligonucleotides, antisense mRNA, autocatalytic ribozymes, and the insertion of a section of DNA to form a triple helix. Proof of principle has been established that inhibition of several cellular proto-oncogenes, including DNA binding protein c-myb, non-muscle myosin heavy chain, PCNA proliferating-cell nuclear antigen, platelet-derived growth factor, basic fibroblast growth factor and c-myc, inhibits smooth muscle cell proliferation in vitro and in several animal models. The first clinical study demonstrated the safety and feasibility of local delivery of antisense in the treatment and prevention of restenosis; another randomised clinical trial (AVAIL) with local delivery of c-myc morpholino compound in patients with coronary artery disease demonstrated its long-term effect on reducing neointimal formation, as well as its safety. These preliminary findings from the small cohort of patients require confirmation in a larger trial utilising more sophisticated drug-eluting technologies. PMID: 15709911 [PubMed - in process] --------------------------------------------------------------- 15: 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] --------------------------------------------------------------- 16: Int J Mol Med. 2005 Feb;15(2):269-75. Functional analysis of the effect of forced activation of STAT3 on M1 mouse leukemia cells. Yoshida T, Iwamoto T, Adachi K, Yokota T, Miyake Y, Hamaguchi M. Department of Ophthalmology, Nagoya University School of Medicine, Showa-ku, Nagoya 466-8550, Japan. M1 mouse myeloid leukemia cells exhibit growth arrest and differentiation to monocytes/macrophages in response to leukemia inhibitory factor (LIF) stimulation. Although recent studies have demonstrated that STAT3 plays a central role in this process, it is unknown whether STAT3 activation alone is sufficient. To address this issue, we have established M1/STAT3ER cells, where STAT3 is selectively activated by 4-hydroxytamoxifen (4HT). 4HT stimulation did not have any effect on growth and morphology of M1/ STAT3ER cells, and did not induce the down-regulation of mRNA of c-myc and c-myb, which is necessary for M1 cell differentiation. On the other hand, mRNA of jun-B, IRF1 and p19 was increased by 4HT. DNA precipitation assay indicated that both stimulation of LIF and 4HT similarly activated STAT3ER. Introduction of a constitutive active MAP kinase kinase (MEK1) into M1/STAT3ER cells did not induce differentiation either. Together, our present data suggest that signaling other than the activation of STAT3 and MEK1 may be necessary for M1 cell-growth arrest and differentiation, while a set of early genes of LIF are induced by only STAT3 activation. PMID: 15647843 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 17: Plant Mol Biol. 2004 May;55(3):327-42. Crosstalk in the responses to abiotic and biotic stresses in Arabidopsis: analysis of gene expression in cytochrome P450 gene superfamily by cDNA microarray. Narusaka Y, Narusaka M, Seki M, Umezawa T, Ishida J, Nakajima M, Enju A, Shinozaki K. Department of Biology, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei-shi, Japan. From Arabidopsis full-length cDNA libraries, we collected ca. 7000 (7K) independent full-length cDNAs to prepare a cDNA microarray. The 7K cDNA collection contains 49 cytochrome P450 genes. In this study, expression patterns of these cytochrome P450 genes were analyzed by a full-length cDNA microarray under various treatments, such as hormones (salicylic acid, jasmonic acid, ethylene, abscisic acid), pathogen-inoculation ( Alternaria brassicicola , Alternaria alternata ), paraquat, rose bengal, UV stress (UV-C), heavy metal stress (CuSO4), mechanical wounding, drought, high salinity and low temperature. Expression of 29 cytochrome P450 genes among them was induced by various treatments. Inoculation with A. brassicicola and A. alternata as biotic stresses increased transcript levels of 12 and 5 genes in Arabidopsis plants, respectively. In addition, some of the genes were also expressed by abiotic stresses. This suggests crosstalk between abiotic and biotic stresses. The promoter sequences and cis -acting elements of each gene were studied on the basis of full-length cDNA sequences. Most cytochrome P450 genes induced by both abiotic and biotic stresses contained the recognition sites of MYB and MYC, ACGT-core sequence, TGA-box and W-box for WRKY transcription factors in their promoters. These cis -acting elements are known to participate in the regulation of plant defense. The response of each gene to multiple stresses is strictly regulated. PMID: 15604685 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 18: Cancer. 2005 Jan 15;103(2):216-28. Richter syndrome: biology, incidence, and therapeutic strategies. Tsimberidou AM, Keating MJ. Department of Leukemia, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA. atsimber@mdanderson.org Richter's transformation denotes the development of high-grade non-Hodgkin lymphoma, prolymphocytic leukemia, Hodgkin disease, or acute leukemia in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma. A search of published articles in Medline (PubMed) and abstracts from professional meetings was performed. An electronic database search of patients with CLL at The University of Texas M. D. Anderson Cancer Center (Houston, TX) determined the incidence of Richter syndrome (RS) in patients with CLL between 1992 and 2002. RS occurs in approximately 5% of patients with CLL. The large cells of RS may arise through transformation of the original CLL clone or represent a new neoplasm. RS may be triggered by viral infections, such as Epstein-Barr virus. Trisomy 12 and chromosome 11 abnormalities are more frequent in patients with RS than in the overall population of patients with CLL. Multiple genetic defects, such as mutations of the p53 tumor suppressor gene, p16INK4A, and p21, loss of p27 expression, deletion of retinoblastoma, increased copy number of C-MYC, and decreased expression of the A-MYB gene, have been described. These abnormalities may cause CLL cells to proliferate and-by facilitating the acquisition of new genetic abnormalities-to transform into RS cells. Therapeutic strategies include intensive chemotherapy, monoclonal antibodies, and stem cell transplantation. The response rates range from 5% to 43% (complete response, 5-38%), and the median survival duration ranges from 5 months to 8 months. In conclusion, RS may be triggered by viral infections or by genetic defects. Current treatments are aggressive, but prognosis is poor. Novel curative treatment strategies are needed. (c) 2004 American Cancer Society. Publication Types: Review Review, Tutorial PMID: 15578683 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 19: J Biol Chem. 2004 Dec 24;279(52):54742-9. Epub 2004 Oct 7. Role of pim-1 in smooth muscle cell proliferation. Katakami N, Kaneto H, Hao H, Umayahara Y, Fujitani Y, Sakamoto K, Gorogawa S, Yasuda T, Kawamori D, Kajimoto Y, Matsuhisa M, Yutani C, Hori M, Yamasaki Y. Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan. The proliferation of vascular smooth muscle cells (VSMCs) and alterations of their phenotype are implicated in the pathogenesis of atherosclerosis. Arterial wall injury induces the expression of proto-oncogenes, leading to the proliferation of VSMCs. In particular, c-Myc and c-Myb play a central role in cell cycle progression and are essential for VSMC replication. The protooncogene Pim-1 cooperates with c-Myc and enhances the transcriptional activity of c-Myb in hematopoietic cells, suggesting that Pim-1 is involved in cell cycle regulation. The aim of this study was to examine the possible involvement of Pim-1 in VSMC proliferation. Pim-1 was substantially induced in neointimal VSMCs of balloon-injured rat carotid arteries, and in vivo infection with a dominant negative Pim-1-expressing adenovirus (Ad-DN-Pim-1) markedly suppressed neointima formation and cell cycle progression in the balloon-injured arteries. In cultured VSMCs, treatment with serum or H(2)O(2) induced Pim-1 expression, and H(2)O(2)- or serum-stimulated cell cycle progression and DNA synthesis were almost completely inhibited by DN-Pim-1 overexpression. Furthermore, we performed immunohisto-chemical staining for Pim-1 in human thoracic aortas and coronary arteries obtained from six individuals at autopsy and found that Pim-1-positive cells are observed predominantly in the thickened intima of the aortas and coronary arteries. To the best of our knowledge, this is the first report showing Pim-1 expression in rodent and human arterial walls. To summarize, Pim-1 expression was observed in the neointima of balloon-injured rat carotid arteries and in human thoracic aortas and coronary arteries showing intimal thickening, and the specific inhibition of Pim-1 function markedly suppressed neointima formation after balloon injury and the proliferation of cultured VSMCs, suggesting that Pim-1 plays a role in VSMC proliferation. PMID: 15471855 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 20: 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] --------------------------------------------------------------- 21: Free Radic Biol Med. 2004 Sep 1;37(5):597-606. 4-hydroxynonenal and regulation of cell cycle: effects on the pRb/E2F pathway. Barrera G, Pizzimenti S, Dianzani MU. Department of Experimental Medicine and Oncology, Section of General Pathology, University of Turin, 10125 Torino, Italy. The hypothesis that 4-hydroxynonenal (HNE), a product of lipid peroxidation, might negatively affect cell proliferation, arose from the observation that lipid peroxidation is very low in tumors. In leukemic cells HNE inhibited cell growth and reduced c-myc and c-myb expression. HNE also induced differentiation in different leukemic cell lines. In HL-60 human leukemic cells, HNE induced the accumulation of cells in the G(0)/G(1) phase of the cell cycle accompanied by a decrease of cyclins D1, D2, and A. Moreover, HNE caused an increase in p21 expression. As cyclin D/CDK2 and cyclin A/CDK2 phosphorylate pRB, these findings suggested that pRb phosphorylation could be affected by HNE. Hypophosphorylated pRb binds and inactivates the E2F transcription factors. HNE induced the dephosphorylation of pRb and the increase in pRb/E2F1 complexes, whereas pRb/E2F4 complexes were reduced, because HNE downregulated E2F4 protein expression. The analysis of E2F binding to the P2 c-myc promoter revealed that HNE caused a decrease in "free" E2F, as well as an increase in pRb (and pRB family members) bound to E2F, with consequent repression of the transcription. In conclusion, HNE reduces E2F transcriptional activity by modifying a number of genes involved in regulation of the pRb/E2F pathway. Publication Types: Review Review of Reported Cases PMID: 15288118 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 22: Basic Res Cardiol. 2004 Jul;99(4):309-14. Epub 2004 Apr 16. Erratum in: Basic Res Cardiol. 2004 Jul;99(4):315. The intron 6 G/T polymorphism of c-myb oncogene and the risk for coronary in-stent restenosis. Gross CM, Kramer J, Pfeufer A, Dietz R, Gessner R, Praus M. HELIOS-Clinic Berlin, Franz Volhard Clinic at Max Delbruck Center for Molecular Medicine, Medical Faculty of the Charite Humboldt University, Wiltberg Strasse 50, 13125 Berlin, Germany. gross@fvk-berlin.de BACKGROUND: The principle mechanisms leading to the development of atherosclerosis are long-term accumulation of lipids and cell proliferation. We have recently shown that a single nucleotide polymorphism in the c-myb gene is associated with the development of coronary artery disease in humans and intracellular lipid accumulation. C-myb expression has been further shown to be up-regulated during cell proliferation. The development of in-stent restenosis is predominantly driven by smooth muscle cell proliferation. METHODS: To study a possible association of c-myb with neointima formation in humans we genotyped 485 consecutive patients undergoing coronary stenting for a G/T-single nucleotide polymorphism in intron 6 of the cmyb gene. Restenosis was assessed by quantitative coronary angiography and angiographic follow-up after 6 months. To study the effect of c-myb on smooth muscle cell proliferation primary human smooth muscle cells were infected with recombinant adenovirus expressing c-myb, a dominant negative myb-engrailed fusion protein or control virus. RESULTS AND CONCLUSION: Restenosis > 50% occurred in 27.6% of patients with at least one G-allele and in 20.8% of those without (p = 0.10). Even after adjustment for the independent risk factors diabetes mellitus, reference lumen diameter, smoking, dyslipidemia and number of diseased vessels, the observed difference in the distribution of the c-myb alleles did not reach statistical significance (p = 0.08). Adenoviral gene transfer of c-myb did not increase proliferation of cultured smooth muscle compared to control virus or untransfected cells, while the expression of the dominant negative mutant reduced proliferation of VSMC as previously shown. Our results indicate that expression of c-myb, while being important for cell cycle is not sufficient to induce smooth muscle cell proliferation. The G/T-nucleotide transversion polymorphism in intron 6 of the c-myb oncogene that has been associated with atherosclerosis and lipid accumulation is not a risk factor for human in-stent restenosis. PMID: 15221349 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 23: Biochem Biophys Res Commun. 2004 May 14;317(4):1096-102. Activation of mouse RAG-2 promoter by Myc-associated zinc finger protein. Wu CX, Zhao WP, Kishi H, Dokan J, Jin ZX, Wei XC, Yokoyama KK, Muraguchi A. Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, 2630, Sugitani, Toyama 930-0194, Japan. Recombination activating gene-1 (RAG-1) and RAG-2 are expressed specifically in lymphocytes undergoing the antigen receptor gene rearrangement during the lymphocyte development. Our previous study showed that the -41 to -17 nucleotides (nt) 5' -upstream region of mouse RAG-2 were pre-requisite for the core promoter activity and that Pax-5/c-Myb/LEF-1 protein-protein complex was responsible for its activity in immature B cells. In this study, we show that the -65/-42 sequence, the non-conserved sequence between human and mouse RAG-2 promoter, is necessary for the full promoter activity for mouse RAG-2. Electrophoresis mobility shift assay revealed that Myc-associated zinc finger protein (MAZ) as well as SP1/3 binds a GA box in this region. Using chromatin immunoprecipitation, we show that MAZ binds the RAG-2 promoter region in pre-B cells. Furthermore, we show that MAZ synergistically activates the murine RAG-2 promoter with Pax-5/c-Myb/LEF-1 complex. These results first demonstrate that MAZ participates in activation of mouse RAG-2 promoter. PMID: 15094381 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 24: Chin Med J (Engl). 2004 Feb;117(2):258-63. In vivo distribution of c-myc antisense oligodeoxynucleotides local delivered by gelatin-coated platinum-iridium stents in rabbits and its effect on apoptosis. Zhang XX, Cui CC, Xu XG, Hu XS, Fang WH, Kuang BJ. Department of Cardiology, Shenzhen Futian Hospital, Guangdong Medical College, Shenzhen 518033, China. BACKGROUND: Post-stenting restenosis is a significant clinical problem, involving vascular smooth muscle cells (VSMCs) proliferation and apoptosis. It is reported that c-myc antisense oligodeoxynucleotides (ASODNs) local delivered by catheter can inhibit VSMCs proliferation. This study was designed to assess tissue distribution of c-myc ASODN local delivered using gelatin-coated platinum-iridium (Pt-Ir) stents, and its effect on apoptosis of VSMCs. METHODS: Gelatin-coated Pt-Ir stents that had absorbed caroboxyfluorescein-5-succimidyl ester (FAM) labeled c-myc ASODNs (550 microg per stent) were implanted into the right carotid arteries of 6 rabbits. Tissue samples were obtained at 45 minutes, 2 hours, and 6 hours. Tissue distribution of c-myc ASODNs was assessed by fluorescence microscopy. In addition, 32 rabbits were randomly divided into two groups. Rabbits in the control group (n = 16) were implanted with gelatin-coated Pt-Ir stents, and those in the treatment group (n = 16) were implanted with gelatin-coated stents that had absorbed c-myc ASODNs. 7, 14, 30, or 90 days (n = 4, respectively, for each group) after the stenting procedure, the stented segments were harvested, and histopathological examinations were performed to calculate neointimal area and mean neointimal thickness. The expression of c-myc was assessed using in situ hybridization (ISH) and immunohistochemical methods. Apoptotic VSMCs were detected using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM). RESULTS: According to fluorescence microscopic results, FAM-labeled c-myc ASODNs were concentrated in the target vessel media at the 45 minutes time point, and then dispersed to the adventitia. Morphometric analysis showed that neointimal area and mean neointimal thickness increased continuously up to 90 days after stent implantation, but that total neointimal area and mean neointimal thickness were less in the treatment group than in the control group at all time points (P < 0.0001). At day 7 and day 14 after stenting, there were no detectable apoptotic cells in either group. However, apoptotic cells were present in the neointima 30 and 90 days after stenting, and the number of apoptotic cells was less at 30 days than at 90 days. Meanwhile, c-myc ASODNs appeared to induce apoptosis in more cells in the treatment group than that in the control group. Typical apoptotic VSMCs were observable under TEM. The expression of c-myc was positive in the control group and negative or weakly positive in the c-myc ASODN treatment group, according to both ISH and immunohistochemical examination. CONCLUSION: Gelatin-coated Pt-Ir stent mediated local delivery of c-myc ASODNs is feasible. The localization of c-myc ASODN is primarily in the target vessel walls. c-myc ASODNs can inhibit VSMCs proliferation and induce its apoptosis after local delivery in vivo. PMID: 14975213 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 25: Cytogenet Genome Res. 2003;102(1-4):309-17. The chicken telomerase RNA gene: conservation of sequence, regulatory elements and synteny among viral, avian and mammalian genomes. Delany ME, Daniels LM. Department of Animal Science, University of California, Davis, CA 95616, USA. medelany@ucdavis.edu Telomerase RNA (TR) is essential for telomerase activity and the maintenance of telomere length in proliferating cell populations. The objective of the present research was to define the cytogenetic and molecular genomic organization of chicken TR (chTR). The chTR exists as a single copy gene (TERC, alias TR), mapping to chromosome 9 (GGA9). The loci on the q arm of GGA9 map to three chromosomes in human with five of the nine GGA9q loci mapping to HSA3q. Sequencing of the chTERC locus (3,763 bp) from the UCD 001 genome (Red Jungle Fowl) included: 604 bp 5', 465 coding, and 2,694 bp 3' (from -604 to +3159). Sequence analysis included homology searches conducted on several levels including comparisons among different chicken genotypes, Marek's disease virus (MDV) sequences, plus human and murine. We provide evidence for distal 5' and 3' sequence homology between chTERC and the MDV genome among other known regions of homology (promoter and coding), elaborate on 5' transcription factor binding motifs among the various genomes as well as show type and number of TERT-related motifs 3' of chicken TR (e.g., Sp1, c-Myb, c-Myc, AP2, among others). Surrounding the gene are more than 25 Sp1 sites, over 20 oncogene transcription factor binding motifs and numerous hormonal and other specialized binding motifs. Knowledge of 5' and 3' chTERC regulatory elements will be useful for investigating normal control mechanisms during growth and development as well as investigating the potential for dysregulation of this important gene during oncogenesis, especially among different genotypes. Copyright 2003 S. Karger AG, Basel PMID: 14970722 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 26: J Biol Chem. 2004 Apr 23;279(17):17715-22. Epub 2004 Feb 9. B-Myb-dependent regulation of c-Myc expression by cytosolic phospholipase A2. Tashiro S, Sumi T, Uozumi N, Shimizu T, Nakamura T. Department of Radiology and Cancer Biology, Nagasaki University School of Dentistry, Nagasaki 852-8588, Japan. Cytosolic phospholipase A(2) (cPLA(2)) cleaves membrane phospholipids to release arachidonic acid, initiating lipoxygenase and cyclooxygenase pathways. Mice lacking a gene for cPLA(2) suggested important roles of the protein in allergic responses, fertility, and neural cell death. Here we show that cPLA(2) negatively regulates c-Myc expression in a B-Myb-dependent manner. Overexpression of cPLA(2) protein but not a mutant cPLA(2) protein that lacks in vitro binding ability with B-Myb inhibits B-Myb-dependent c-myc gene expression. The inhibition was associated with physical interaction of B-Myb protein with cPLA(2) both in the cytoplasm and the nucleus. Binding site analysis demonstrated that both the N and C termini of cPLA(2) interact with B-Myb. Macrophage colony stimulating factor (MCSF) stimulated cPLA(2) redistribution into the nucleus and also association with B-Myb in human monocytes. Importantly, macrophages from mice with a disrupted cPLA(2) gene demonstrated significantly increased levels of c-Myc protein in the nucleus compared with cells from the wild-type mice, whereas B-Myb levels were similar in the cells from the cPLA(2)(+/+) and cPLA(2)(-/-) mice. Moreover, an introduction of cPLA(2) into cPLA(2)(-/-) mouse macrophages resulted in decreased c-Myc protein levels, and an inhibition of cPLA(2) expression by small interfering RNAs or antisense RNA increased the c-myc transcription in macrophage colony stimulating factor-activated human monocytes. These findings provide new insights into the function of cPLA(2) in B-Myb-dependent gene expression. PMID: 14769798 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 27: Zhonghua Xue Ye Xue Za Zhi. 2003 Dec;24(12):629-31. [Indomethacin-induced HL-60 cell apoptosis is associated with inhibition of beta-catenin/c-myc signal transduction pathway] [Article in Chinese] Zhang GS, Wang ZY. Division of Hematology, the Second Xiangya Hospital, Central South University, Changsha 410011, China. OBJECTIVE: To investigate the effects of indomethacin on HL-60 cell proliferation and apoptosis, and elucidate partly the molecular mechanism about the anti-leukemia effect of indomethacin by studying beta-catenin signal transduction pathway. METHODS: HL-60 cells were treated with indomethacin at different concentrations (0, 25, 50, 100, 200, 400 micro mol/L). Cells viability and proliferation were determined by Trypan blue staining and cell counting respectively. DNA ladder pattern and cell morphology were used to identify cell apoptosis. The expression and cleavage of caspase-3, beta-catenin, c-myc were detected by Western blot techniques. RESULTS: Indomethacin could significantly inhibit HL-60 cells proliferation and induce cells apoptosis with a time and dose dependent manner. An up-regulating expression and cleavage of caspase-3 were observed. Indomethacin could inhibit beta-catenin expression and induce its degradation, c-myc protein exhibited a down-regulation with a concentration dependent manner. CONCLUSION: Indomethacin could inhibit HL-60 cell proliferation and induce cells apoptosis. Anti-leukemia effect of indomethacin was associated with the inhibition of "beta-catenin --> c-myc" signal pathway. PMID: 14761609 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 28: Int J Vitam Nutr Res. 2003 Nov;73(6):461-7. Expression of oncogenes depends on biotin in human small cell lung cancer cells NCI-H69. Scheerger SB, Zempleni J. Department of Nutritional Science and Dietetics, University of Nebraska at Lincoln, Lincoln, NE 68583, USA. Oncogenes play important roles in cell proliferation and biotin status correlates with gene expression and proliferation rates in human cells. In this study we determined whether biotin supply affects biotin homeostasis, expression of oncogenes, and proliferation rates in NCI-H69 small cell lung cancer cells. NCI-H69 cells were cultured in media containing deficient (0.025 nmol/L), physiologic (0.25 nmol/L), or pharmacologic (10 nmol/L) concentrations of biotin for 3 weeks. Biotin concentrations in culture media correlated negatively with biotin transport rates, suggesting that cells responded to marginal biotin supply with increased expression of biotin transporters. Increased biotin uptake was not sufficient to prevent depletion of intracellular biotin in cells cultured in biotin-deficient medium, as judged by decreased activity of biotin-dependent propionyl-CoA carboxylase and decreased biotinylation of histones. The expression of oncogenes N-myc, c-myb, N-ras, and raf correlated with biotin supply in media: oncogene expression increased by up to 20% in cells cultured in pharmacologic medium compared to physiologic controls; oncogene expression decreased by up to 47% in cells cultured in deficient medium. This observation is consistent with a role for biotin in oncogene-dependent metabolic pathways. Cellular uptake of thymidine (marker for proliferation) was not affected by biotin supply, suggesting that effects of biotin-dependent expression of oncogenes on the growth of tumor cells are quantitatively minor. The clinical significance of effects of biotin supply on expression of oncogenes remains to be elaborated. PMID: 14743551 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 29: Clin Cancer Res. 2003 Nov 1;9(14):5271-81. Gene amplifications associated with the development of hormone-resistant prostate cancer. Edwards J, Krishna NS, Witton CJ, Bartlett JM. University of Glasgow, Glasgow, United Kingdom. PURPOSE: Hormone resistance remains a significant clinical problem in prostate cancer with few therapeutic options. Research into mechanisms of hormone resistance is essential. EXPERIMENTAL DESIGN: We analyzed 38 paired (prehormone/posthormone resistance) prostate cancer samples using the Vysis GenoSensor. Archival microdissected tumor DNA was extracted, amplified, labeled, and hybridized to Amplionc I DNA microarrays containing 57 oncogenes. RESULTS: Genetic instability increased during progression from hormone-sensitive to hormone-resistant cancer (P = 0.008). Amplification frequencies of 15 genes (TERC, MYBL3, HRAS, PI3KCA, JUNB, LAMC2, RAF1, MYC, GARP, SAS, FGFR1, PGY1, MYCL1, MYB, FGR) increased by >10% during hormone escape. Receptor tyrosine kinases were amplified in 73% of cases; this was unrelated to development of hormone resistance. However, downstream receptor tyrosine kinase signaling pathways showed increased amplification rates in resistant tumors for the mitogen-activated protein kinase (FGR/Src-2, HRAS, and RAF1; P = 0.005) and phosphatidylinositol 3'-kinase pathways (FGR/Src-2, PI3K, and Akt; P = 0.046). Transcription factors regulated by these pathways were also more frequently amplified after escape (MYC family: 21% before versus 63% after, P = 0.027; MYB family: 26% before versus 53% after, P = 0.18). CONCLUSIONS: Development of clinical hormone escape is linked to phosphatidylinositol 3'-kinase and mitogen-activated protein kinase pathways. These pathways may function independently of the androgen receptor or via androgen receptor activation by phosphorylation, providing novel therapeutic targets. PMID: 14614009 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 30: Mol Cell Biol. 1982 Jun;2(6):617-24. Transcripts from the cellular homologs of retroviral oncogenes: distribution among chicken tissues. Gonda TJ, Sheiness DK, Bishop JM. Department of Microbiology and Immunology, University of California, San Francisco, California 94143, USA. The oncogenes (v-onc genes) of rapidly transforming retroviruses have homologs (c-onc genes) in the genomes of normal cells. In this study, we characterized and quantitated transcription from four c-onc genes, c-myb, c-myc, c-erb, and c-src, in a variety of chicken cells and tissues. Electrophoretic analysis of polyadenylated RNA, followed by transfer to nitrocellulose and hybridization to cloned onc probes showed that c-myb, c-myc, and c-src each give rise to a single mature transcript, whereas c-erb gives rise to multiple transcripts (B. Vennstrom and J. M. Bishop, Cell, in press) which vary in abundance among different cells and tissues. Transcription from c-myb, c-myc, c-erb, and c-src was quantitated by a "dot-blot" hybridization assay. We found that c-myc, c-erb, and c-src transcription could be detected in nearly all cells and tissues examined, whereas c-myb transcription was detected only in some hemopoietic cells; these cells, however, belong to several different lineages. Thus, in no case was expression of a c-onc gene restricted to a single cell lineage. There appeared to be a correlation between levels of c-myb expression and hemopoietic activity of the tissues and cells examined, which suggests that c-myb may be expressed primarily in immature hemopoietic cells. An examination of c-onc RNA levels in target cells and tissues for viruses carrying the corresponding v-onc genes revealed no obvious correlation, direct or inverse, between susceptibility to transformation by a given v-onc gene and expression of the homologous c-onc gene. PMID: 14582157 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 31: 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] --------------------------------------------------------------- 32: 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] --------------------------------------------------------------- 33: Phytochemistry. 2003 Sep;64(2):367-83. New perspectives on proanthocyanidin biochemistry and molecular regulation. Marles MA, Ray H, Gruber MY. Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, Saskatchewan S7N 0X2, Canada. Our understanding of proanthocyanidin (syn. condensed tannin) synthesis has been recently extended by substantial developments concerning both structural and regulatory genes. A gene encoding leucoanthocyanidin reductase has been obtained from the tropical forage, Desmodium uncinatum, with the latter enzyme catalyzing formation of (+)-catechin. The BANYULS gene in Arabidopsis thaliana, previously proposed to encode leucoanthocyanidin reductase or to regulate proanthocyanidin biosynthesis, has been shown instead to encode anthocyanidin reductase, which in turn converts anthocyanidins (pelargonidin, cyanidin, or delphinidin) into 2,3-cis-2R,3R-flavan-3-ols (respectively, (-)-epiafzelechin, (-)-epicatechin and (-)-epigallocatechin). However, the enzyme which catalyzes the polymerization reaction remains unknown. Nevertheless, a vacuolar transmembrane protein TT12, defined by the Arabidopsis tt12 mutant, is involved in transport of proanthocyanidin polymer into the vacuole for accumulation. Six different types of regulatory elements, e.g. TFIIIA-like, WD-40-like, WRKY-like, MADS-box-like, myb-like, and bHLH (myc-like), have been cloned and identified using mutants from Arabidopsis (tt1, ttg1, ttg2, tt2, tt16, tt2, tt8) and two other species (Hordeum vulgare [ant13] and Lotus spp [tan1]). Accordingly, increases in proanthocyanidin levels have been induced in the the world's major forage, alfalfa. These advances may now lead to a detailed understanding of how PA synthesis is controlled and to useful alterations in proanthocyanidin concentration for the improvement of forage species, pulses, and other crop plants. Publication Types: Review PMID: 12943753 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 34: Carcinogenesis. 2003 Sep;24(9):1549-59. Epub 2003 Aug 1. Forced expression of antisense 14-3-3beta RNA suppresses tumor cell growth in vitro and in vivo. Sugiyama A, Miyagi Y, Komiya Y, Kurabe N, Kitanaka C, Kato N, Nagashima Y, Kuchino Y, Tashiro F. Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Yamazaki 2641, Noda-shi, Chiba 278-8510, Japan. The 14-3-3 family proteins are key regulators of various signal transduction pathways including malignant transformation. Previously, we found that the expression of the 14-3-3beta gene is deregulated as well as c-myc gene in aflatoxin B1 (AFB1)-induced rat hepatoma K1 and K2 cells. To elucidate the implication of 14-3-3beta in tumor cell growth, in this paper we analyzed the effect of forced expression of antisense 14-3-3beta RNA on the growth and tumorigenicity of K2 cells. K2 cells transfected with antisense 14-3-3beta cDNA expression vector diminished their growth ability in monolayer culture and in semi-solid medium. Expression level of vascular endothelial growth factor mRNA was also reduced in these transfectants. Tumors that formed by the transfectants in nude mice were much smaller and histologically more benign tumors, because of their decreased level of mitosis compared with those of the parental cells. Frequency of apoptosis detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay was increased in the transfectant-derived tumors accompanying the inhibition of angiogenesis. In addition, over-expression of 14-3-3beta mRNA was observed in various murine tumor cell lines. These results suggest that 14-3-3beta gene plays a pivotal role in abnormal growth of tumor cells in vitro and in vivo. PMID: 12896901 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 35: Endocr Relat Cancer. 2003 Jun;10(2):111-30. Adaptive hypersensitivity to estrogen: mechanism for superiority of aromatase inhibitors over selective estrogen receptor modulators for breast cancer treatment and prevention. Santen RJ, Song RX, Zhang Z, Kumar R, Jeng MH, Masamura S, Yue W, Berstein L. Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA. rjs5y@hscmail.mcc.virginia.edu Clinical observations suggest that human breast tumors can adapt to endocrine therapy by developing hypersensitivity to estradiol (E(2)). To understand the mechanisms responsible, we examined estrogenic stimulation of cell proliferation in a model system and provided in vitro and in vivo evidence that long-term E(2) deprivation (LTED) causes "adaptive hypersensitivity". The enhanced responses to E(2) do not involve mechanisms acting at the level of transcription of estrogen-regulated genes. We found no evidence of hypersensitivity when examining the effects of E(2) on regulation of c-myc, pS2, progesterone receptor, several estrogen receptor (ER) reporter genes, or c-myb in hypersensitive cells. Estrogen deprivation of breast cells long-term does up-regulate both the MAP kinase and phosphatidyl-inositol 3-kinase pathways. As a potential explanation for up-regulation of these signaling pathways, we found that ERalpha is 4- to 10-fold up-regulated and co-opts a classic growth factor pathway using Shc, Grb-2 and Sos. This induces rapid non-genomic effects which are enhanced in LTED cells. E(2) binds to cell membrane-associated ERalpha, physically associates with the adapter protein SHC, and induces its phosphorylation. In turn, Shc binds Grb-2 and Sos, which results in the rapid activation of MAP kinase. These non-genomic effects of E(2) produce biological effects as evidenced by Elk activation and by morphological changes in cell membranes. Further proof of the non-genomic effects of E(2) involved use of cells which selectively expressed ERalpha in the nucleus, cytosol and cell membrane. We created these COS-1 "designer cells" by transfecting ERalpha lacking a nuclear localization signal and containing a membrane localizing signal. The concept of "adaptive hypersensitivity" and the mechanisms responsible for this phenomenon have important clinical implications. Adaptive hypersensitivity would explain the superiority of aromatase inhibitors over the selective ER modulators (SERMs) for treatment of breast cancer. The development of highly potent third-generation aromatase inhibitors allows reduction of breast tissue E2 to very low levels and circumvents the enhanced sensitivity of these cells to the proliferative effects of E(2). Clinical trials in the adjuvant, neoadjuvant and advanced disease settings demonstrate the greater clinical efficacy of the aromatase inhibitors over the SERMs. More recent observations indicate that the aromatase inhibitors are superior for the prevention of breast cancer as well. These observations may be explained by the hypothesis that estrogens induce breast cancer both by stimulating cell proliferation and by their metabolism to genotoxic products. The SERMs block ER-mediated proliferation only, whereas the aromatase inhibitors exert dual effects on proliferation and genotoxic metabolite formation. Publication Types: Review Review, Tutorial PMID: 12790774 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 36: Eur J Cancer. 2003 May;39(8):1165-75. Histone acetylation-mediated regulation of genes in leukaemic cells. Chambers AE, Banerjee S, Chaplin T, Dunne J, Debernardi S, Joel SP, Young BD. Cancer Research UK Medical Oncology Laboratory, The Medical College of St. Bartholomew's Hospital, Charterhouse Square, London, EC1M 6QB, UK. annechambers@yahoo.co.uk Histone deacetylase (HDAC) and histone acetyltransferase (HAT) functions are associated with various cancers, and the inhibition of HDAC has been found to arrest disease progression. Here, we have investigated the gene expression profiles of leukaemic cells in response to the HDAC inhibitor trichostatin A (TSA) using oligonucleotide microarrays. Nucleosomal histone acetylation was monitored in parallel and the expression profiles of selected genes were confirmed by quantitative polymerase chain reaction (PCR). A large number of genes (9% of the genome) were found to be similarly regulated in CCRF-CEM and HL-60 cells in response to TSA, and genes showing primary and secondary responses could be distinguished by temporal analysis of gene expression. A small fraction of genes were highly sensitive to histone hyper-acetylation, including XRCC1, HOXB6, CDK10, MYC, MYB, NMI and CBFA2T3 and many were trans-acting factors relevant to cancer. The most rapidly repressed gene was MKRN3, an imprinted gene involved in the Prader-Willi syndrome. PMID: 12736119 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 37: Blood. 2003 Aug 1;102(3):849-57. Epub 2003 Apr 10. Telomerase levels control the lifespan of human T lymphocytes. Roth A, Yssel H, Pene J, Chavez EA, Schertzer M, Lansdorp PM, Spits H, Luiten RM. Terry Fox Laboratory, British Columbia Cancer Agency and University of British Columbia, Vancouver, Canada. The loss of telomeric DNA with each cell division contributes to the limited replicative lifespan of human T lymphocytes. Although telomerase is transiently expressed in T lymphocytes upon activation, it is insufficient to confer immortality. We have previously shown that immortalization of human CD8+ T lymphocytes can be achieved by ectopic expression of the human telomerase reverse transcriptase (hTERT) gene, which encodes for the catalytic component of the telomerase complex. To study the role of endogenous hTERT in the lifespan of human T cells, we blocked endogenous hTERT expression by ectopic expression of dominant-negative (DN) hTERT. Cells expressing DN-hTERT had a decreased lifespan and showed cytogenetic abnormalities, including chromosome ends without detectable telomeric DNA as well as chromosome fusions. These results indicate that while endogenous hTERT cannot prevent overall telomere shortening, it has a major influence on the longevity of human T cells. Furthermore, we show that up-regulation of hTERT in T cells upon activation decreases over time in culture. Long-term-cultured T cells also show a decreased expression of c-myc upon activation, resulting in less c-myc-induced transcription of hTERT. Moreover, memory T cells, which have expanded in vivo upon antigen encounter, expressed a lower level of hTERT upon activation than naive cells from the same donor. The observed inverse correlation between telomerase levels and replicative history suggests that telomerase levels in T cells are limiting and increasingly insufficient to sustain their proliferation. PMID: 12689947 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 38: Expert Opin Ther Targets. 2003 Apr;7(2):235-48. Targeting c-Myb expression in human disease. Ramsay RG, Barton AL, Gonda TJ. Differentiation and Transcription Group, Trescowthick Laboratories, Peter MacCallum Cancer Institute, Victoria, Australia. r.ramsay@pmci.unimelb.edu.au c-Myb is a transcription factor employed in the haematopoietic system and gastrointestinal tract to regulate the exquisite balance between cell division, differentiation and survival. In its absence, these tissues either fail to form, or show aberrant biology. Mice lacking a functional c-myb gene die in utero by day 15 of development. When inappropriately expressed, as is common in leukaemia and epithelial cancers of the breast, colon and gastro-oesophagus, c-Myb appears to activate gene targets of key importance to cancer progression and metastasis. These genes include cyclooxygenase-2 (COX-2), Bcl-2, BclX(L) and c-Myc, which influence diverse processes such as angiogenesis, proliferation and apoptosis. The clinical potential for blocking c-Myb expression in malignancies is based upon strong preclinical data and some trial-based evidence. The modest clinical experience to date has been with haematopoietic malignancies, but other disease classes may be amenable to similar interventions. The frontline agents to achieve this are nuclease-resistant oligodeoxynucleotides (ODNs), which are proving to be acceptable therapeutic reagents in terms of tolerable toxicities and delivery. Nevertheless, further effort must be focused on improving their efficacy, eliminating non-specific toxicity and optimising delivery. Optimisation issues aside, it would appear that anti-c-Myb therapies will be used with most success when combined with other agents, some of which will be established cytotoxic and differentiation-inducing drugs. This review will explore the future strategic use of ODNs in vivo, focusing on a wide spectrum of diseases, including several beyond the haematopoietic malignancies, in which c-Myb appears to play a role. PMID: 12667100 [PubMed - in process] --------------------------------------------------------------- 39: J Pharmacol Exp Ther. 2003 Jun;305(3):932-42. Epub 2003 Mar 20. Peroxisome proliferator-activated receptor ligands affect growth-related gene expression in human leukemic cells. Laurora S, Pizzimenti S, Briatore F, Fraioli A, Maggio M, Reffo P, Ferretti C, Dianzani MU, Barrera G. Department of Medicine, University of Turin, Italy. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear receptors. Three subtypes of PPARs (alpha, beta, and gamma) have been identified in different tissues. PPAR alpha and PPAR gamma ligands inhibit cell proliferation and induce differentiation in several human cell models. We demonstrated that both PPAR alpha (clofibrate and ciprofibrate) and PPAR gamma ligands (troglitazone and 15 deoxy-prostaglandin J2, 15d-PGJ2) inhibited growth, induced the onset of monocytic-like differentiation, and increased the proportion of G0/G1 cells in the HL-60 leukemic cell line. Moreover, 3 days after the treatment with 2.5 microM 15d-PGJ2, an increase in sub-G0/G1 population occurred, compatible with an induction of programmed cell death. To clarify the mechanisms involved in HL-60 growth inhibition due to the effects of PPAR ligands, we investigated their action on the expression of some genes involved in the control of cell proliferation, differentiation, and cell cycle progression such as c-myc, c-myb, and cyclin D1 and D2. Clofibrate (50 microM), ciprofibrate (50 microM), and 15d-PGJ2 (2.5 microM) inhibited c-myb and cyclin D2 expression, whereas they did not affect c-myc and cyclin D1 expression. Only troglitazone (5 microM) decreased c-myc mRNA and protein levels, besides decreasing c-myb and cyclin D2. The down-regulations of c-myb and cyclin D2 expression represent the first evidence of the inhibitory effect exerted by PPAR ligands on these genes. Moreover, the inhibition of c-myc expression by troglitazone may depend on a PPAR-independent mechanism. PMID: 12649303 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 40: Mol Cancer Res. 2003 Feb;1(4):300-11. Tamoxifen functions as a molecular agonist inducing cell cycle-associated genes in breast cancer cells. Hodges LC, Cook JD, Lobenhofer EK, Li L, Bennett L, Bushel PR, Aldaz CM, Afshari CA, Walker CL. Department of Carcinogenesis, UT M.D. Anderson Cancer Center, Smithville, TX 78957, USA. Tamoxifen is a widely used breast cancer therapeutic and preventative agent. Although functioning as an estrogen antagonist at the cellular level, transcriptional profiling revealed that at the molecular level, tamoxifen functions largely as an agonist, virtually recapitulating the gene expression profile induced in breast cancer cells by estrogen. Remarkably, tamoxifen induces transcription factors and genes involved in promoting cell cycle progression including fos, myc, myb, cdc25a, cyclins E and A2, and stk15 with kinetics that paralleled that of cells cycling in response to estrogen, even though tamoxifen-treated cells are not transiting through the cell cycle. Induction of cell cycle-associated genes was specific for tamoxifen, and did not occur with raloxifene. However, cyclin D1 was a key estrogen-induced gene not expressed in response to tamoxifen or raloxifene but constitutively expressed in tamoxifen-resistant cells. PMID: 12612058 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 41: Oncogene. 2003 Feb 20;22(7):1073-86. Functional genomic analysis reveals distinct neoplastic phenotypes associated with c-myb mutation in the bursa of Fabricius. Neiman PE, Grbic JJ, Polony TS, Kimmel R, Bowers SJ, Delrow J, Beemon KL. Divisions of Basic Science and Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. pneiman@fhere.org Avian retroviral integration into the c-myb locus is casually associated with the development of lymphomas in the bursa of Farbricius of chickens; these arise with a shorter latency than bursal lymphomas caused by deregulation of c-myc. This study indicates that c-myb mutation in embryonic bursal precursors leads to an oligoclonal population of developing bursal follicles, showing a variable propensity to form a novel lesion, the neoplastic follicle (NF). About half of such bursas rapidly developed lymphomas. Detection of changes in gene expression, during the development of neoplasms, was carried out by cDNA microarray analysis. The transcriptional signature of lymphomas with mutant c-myb was more limited than, and only partially shared with, those of bursal lymphomas caused by Myc or Rel oncogenes. The c-myb-associated lymphomas frequently showed overexpression of c-myc and altered expression of other genes involved in cell cycle control and proliferation-related signal transduction. Oligoclonal, NF-containing bursas lacked detectable c-myc overexpression and demonstrated a pattern of gene expression distinct from that of normal bursa and partially shared with the short-latency lymphomas. This functional genomic analysis uncovered several different pathways of lymphomagenesis by oncogenic transcription factors acting in a B-cell lineage. PMID: 12592394 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 42: J Virol. 2003 Feb;77(3):2056-62. Genome-based identification of cancer genes by proviral tagging in mouse retrovirus-induced T-cell lymphomas. Kim R, Trubetskoy A, Suzuki T, Jenkins NA, Copeland NG, Lenz J. Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA. The identification of tumor-inducing genes is a driving force for elucidating the molecular mechanisms underlying cancer. Many retroviruses induce tumors by insertion of viral DNA adjacent to cellular oncogenes, resulting in altered expression and/or structure of the encoded proteins. The availability of the mouse genome sequence now allows analysis of retroviral common integration sites in murine tumors to be used as a genetic screen for identification of large numbers of candidate cancer genes. By positioning the sequences of inverse PCR-amplified, virus-host junction fragments within the mouse genome, 19 target genes were identified in T-cell lymphomas induced by the retrovirus SL3-3. The candidate cancer genes included transcription factors (Fos, Gfi1, Lef1, Myb, Myc, Runx3, and Sox3), all three D cyclins, Ras signaling pathway components (Rras2/TC21 and Rasgrp1), and Cmkbr7/CCR7. The most frequent target was Rras2. Insertions as far as 57 kb away from the transcribed portion were associated with substantially increased transcription of Rras2, and no coding sequence mutations, including those typically involved in Ras activation, were detected. These studies demonstrate the power of genome-based analysis of retroviral insertion sites for cancer gene discovery, identify several new genes worth examining for a role in human cancer, and implicate the pathways in which those genes act in lymphomagenesis. They also provide strong genetic evidence that overexpression of unmutated Rras2 contributes to tumorigenesis, thus suggesting that it may also do so if it is inappropriately expressed in human tumors. PMID: 12525640 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 43: J Biol Chem. 2003 Mar 28;278(13):11480-8. Epub 2003 Jan 13. c-Myc is essential but not sufficient for c-Myb-mediated block of granulocytic differentiation. Kumar A, Lee CM, Reddy EP. Fels Institute for Cancer Research and Molecular Biology and the M.D./Ph.D. Program, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA. The c-myb proto-oncogene plays a central role in hematopoiesis and encodes a major translational product of 75 kDa. c-Myb is highly expressed in immature hematopoietic cells, and its expression is down-regulated during terminal differentiation. Deregulated expression of c-Myb has been shown to block terminal differentiation of hematopoietic cells. Here we have studied the mechanism of action and the nature of target genes through which c-Myb mediates the block in differentiation of 32Dcl3 murine myeloid cells. We show that the ectopic overexpression of c-Myb in 32Dcl3 cells results in the overexpression of c-Myc. However, enforced expression of c-Myc in 32Dcl3 cells did not alter the normal pattern of differentiation. In addition, expression of dominant-negative mutants of c-Myc relieved c-Myb-mediated block in differentiation. These results led us to conclude that c-myc is a target gene of c-Myb and activation of the c-myc gene is a necessary event in Myb-mediated transformation. However, c-Myc expression alone is inadequate to elicit the phenotypic effects seen with Myb-mediated block in differentiation of myeloid cells, suggesting that activation of additional transcriptional targets by c-Myb plays a critical role in this process. PMID: 12525485 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 44: Plant Cell. 2003 Jan;15(1):63-78. Arabidopsis AtMYC2 (bHLH) and AtMYB2 (MYB) function as transcriptional activators in abscisic acid signaling. Abe H, Urao T, Ito T, Seki M, Shinozaki K, Yamaguchi-Shinozaki K. Biological Resources Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan. In Arabidopsis, the induction of a dehydration-responsive gene, rd22, is mediated by abscisic acid (ABA). We reported previously that MYC and MYB recognition sites in the rd22 promoter region function as cis-acting elements in the drought- and ABA-induced gene expression of rd22. bHLH- and MYB-related transcription factors, rd22BP1 (renamed AtMYC2) and AtMYB2, interact specifically with the MYC and MYB recognition sites, respectively, in vitro and activate the transcription of the beta-glucuronidase reporter gene driven by the MYC and MYB recognition sites in Arabidopsis leaf protoplasts. Here, we show that transgenic plants overexpressing AtMYC2 and/or AtMYB2 cDNAs have higher sensitivity to ABA. The ABA-induced gene expression of rd22 and AtADH1 was enhanced in these transgenic plants. Microarray analysis of the transgenic plants overexpressing both AtMYC2 and AtMYB2 cDNAs revealed that several ABA-inducible genes also are upregulated in the transgenic plants. By contrast, a Ds insertion mutant of the AtMYC2 gene was less sensitive to ABA and showed significantly decreased ABA-induced gene expression of rd22 and AtADH1. These results indicate that both AtMYC2 and AtMYB2 proteins function as transcriptional activators in ABA-inducible gene expression under drought stress in plants. PMID: 12509522 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 45: J Virol. 2003 Jan;77(2):1059-68. Long-range effects of retroviral insertion on c-myb: overexpression may be obscured by silencing during tumor growth in vitro. Hanlon L, Barr NI, Blyth K, Stewart M, Haviernik P, Wolff L, Weston K, Cameron ER, Neil JC. Molecular Oncology Laboratory, Department of Veterinary Pathology, University of Glasgow, Bearsden, United Kingdom. lh40w@udcf.gla.ac.uk The c-myb oncogene is a frequent target for retroviral activation in hemopoietic tumors of avian and mammalian species. While insertions can target the gene directly, numerous clusters of retroviral insertion sites have been identified which map close to c-myb and outside the transcription unit in T-lymphomas (Ahi-1, fit-1, and Mis-2) and monocytic and myeloid leukemias (Mml1, Mml2, Mml3, and Epi-1). Previous analyses showed no consistent effect of these insertions on c-myb expression, raising the possibility that other nearby genes were the true targets. In contrast, our analysis of four cell lines established from lymphomas bearing insertions at fit-1 (fti-1) (feline leukemia virus) and Ahi-1 (Moloney murine leukemia virus) shows that these display higher expression levels of c-myb RNA and protein compared to a panel of phenotypically similar cell lines lacking such insertions. An interesting feature of the cell lines with long-range c-myb insertions was that each also carried an activated Myc allele. The potential for oncogenic synergy between Myb and Myc in T-cell lymphoma was confirmed in transgenic mice overexpressing alleles of both genes in the T-cell compartment, lending further credence to the case for c-myb as the major target for long-range activation. In contrast, mapping and analysis of c-myb neighboring genes (HBS1 and FLJ20069) showed that the expression of these genes did not correlate well with the presence of proviral insertions. A possible explanation for the paradoxical behavior of c-myb was provided by one of the murine T-lymphoma lines bearing an insertion at Ahi-1 (p/m16i) that reproducibly down-regulated c-myb RNA and protein to very low levels or undetectable levels on prolonged culture. Our observations implicate c-myb as a key target of upstream and downstream retroviral insertions. However, overexpression may become dispensable during outgrowth in vitro, and perhaps during tumor progression in vivo, providing a potential rationale for the previously observed discordance between retroviral insertion and c-myb expression levels. PMID: 12502821 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 46: 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] --------------------------------------------------------------- 47: J Virol. 2002 Sep;76(18):9046-59. Ahi-1, a novel gene encoding a modular protein with WD40-repeat and SH3 domains, is targeted by the Ahi-1 and Mis-2 provirus integrations. Jiang X, Hanna Z, Kaouass M, Girard L, Jolicoeur P. Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, H2W 1R7 Quebec, Canada. The Ahi-1 locus was initially identified as a common helper provirus integration site in Abelson pre-B-cell lymphomas and shown to be closely linked to the c-myb proto-oncogene. Since no significant alteration of c-myb expression was found in Abelson murine leukemia virus-induced pre-B-lymphomas harboring a provirus inserted within the Ahi-1 locus, this suggested that it harbors another gene whose dysregulation is involved in tumor formation. Here we report the identification of a novel gene (Ahi-1) targeted by these provirus insertional mutations and the cloning of its cDNA. The Ahi-1 proviral insertions were found at the 3' end of the gene, in an inverse transcriptional orientation, with most of them located around and downstream of the last exon, whereas another insertion was within intron 22. In addition, another previously identified provirus insertion site, Mis-2, was found to map within the 16th intron of the Ahi-1 gene. The Ahi-1 cDNA encodes a 1,047-amino-acid protein. The predicted Ahi-1 protein is a modular protein that contains one SH3 motif and seven WD40 repeats. The Ahi-1 gene is conserved in mammals and encodes two major RNA species of 5 and 4.2 kb and several other shorter splicing variants. The Ahi-1 gene is expressed in mouse embryos and in several organs of the mouse and rat, notably at high levels in the brain and testes. In tumor cells harboring insertional mutations in Ahi-1, truncated Ahi-1/viral fused transcripts were identified, including some splicing variants with deletion of the SH3 domain. Therefore, Ahi-1 is a novel gene targeted by provirus insertion and encoding a protein that exhibits several features of a signaling molecule. Thus, Ahi-1 may play an important role in signal transduction in normal cells and may be involved in tumor development, possibly in cooperation with other oncogenes (such as v-abl and c-myc) or with a tumor suppressor gene (Nf1), since Ahi-1 insertion sites were identified in tumors harboring v-abl defective retroviruses or a c-myc transgene or in tumors exhibiting deletion of Nf1. PMID: 12186888 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 48: Mol Cell Endocrinol. 2002 Jul 31;193(1-2):29-42. Adaptive mechanisms induced by long-term estrogen deprivation in breast cancer cells. Song RX, Santen RJ, Kumar R, Adam L, Jeng MH, Masamura S, Yue W. Department of Medicine, University of Virginia Health Sciences System, Charlottesville, VA, USA. Clinical observations suggest that human breast tumors can adapt in response to endocrine therapy by developing hypersensitivity to estradiol. To understand the mechanisms responsible, we examined estrogenic stimulation of cell proliferation in a model system and provided evidence that long-term deprivation of estradiol causes adaptive hypersensitivity. The enhanced responses to estradiol do not involve mechanisms acting at the level of transcription of estrogen regulated genes. We found no evidence of hypersensitivity when examining the effects of estradiol on regulation of c-myc, pS2, progesterone receptor, several ER reporter genes or c-myb in hypersensitive cells. On the other hand, deprivation of breast cells long term was found to up-regulate a separate pathway whereby the estrogen receptor co-opts a classical growth factor pathway and induces rapid non-genomic effects. Through this pathway, estradiol caused rapid activation of mitogen-activated protein (MAP) kinase. In exploring the mechanisms mediating this event, we found that estradiol binds to cell membrane associated estrogen receptors and causes phosphorylation of Shc, an adaptor protein usually involved in growth factor signaling pathways. ERalpha was found to complex with Shc under these conditions. In turn, Shc bound Grb-2 and Sos which resulted in the activation of MAP kinase. The pure antiestrogen, ICI 182,780, blocked several steps in the rapidly responding ER alpha, Shc, MAP kinase pathway. These non-genomic effects of estradiol produced biologic effects by activating Elk and by inducing morphologic changes in cell membranes. Using confocal microscopy, we demonstrated that estradiol caused a rapid alteration in membrane ruffling, the formation of pseudopodia and translocation of ER alpha to regions contiguous with the cell membrane. These morphologic effects could be blocked with a pure anti-estrogen. We conclude that long-term estradiol deprived cells utilize both genomic (transcriptional) and rapid, non-genomic estradiol induced pathways. We postulate that synergy between these two pathways acting at the level of the cell cycle is responsible for adaptive hypersensitivity. Copyright 2002 Elsevier Science Ireland Ltd. PMID: 12160999 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 49: Plant Mol Biol. 2002 Sep;50(1):111-27. Characterization of cis-acting element involved in cell cycle phase-independent activation of Arath;CycB1;1 transcription and identification of putative regulatory proteins. Planchais S, Perennes C, Glab N, Mironov V, Inze D, Bergounioux C. Institut de Biotechnologie des Plantes, UMR 8618, Universite Paris-Sud, Orsay, France. Progression through the cell cycle is driven by cyclin-dependent kinases (CDKs) whose activity is controlled by regulatory subunits called cyclins. The expression of cyclins is subject to numerous controls at multiple levels, not least at the level of transcription. As a first step to unravel the mechanisms that regulate expression of B-cyclins in plants, we undertook the identification of the required promoter elements of the Arath;CycB1;1 gene. A detailed analysis of different promoter fragments consisted in analysing their ability to mediate cell cycle-dependent transcriptional oscillations of the gus reporter gene in transformed BY-2 cell lines. We showed that different promoter regions took part in transcriptional activation. Furthermore, 202 bp upstream of the ATG were sufficient to induce M-phase-specific expression. This region contains an 18 bp sequence including a Myb-binding core (AACGG) which is able to activate reporter gene without leading to M-phase-specific expression. Electrophoretic mobility shift assays showed that this 18 bp sequence specifically binds protein complexes from Arabidopsis cell suspension enriched either in G1 or G2 phase. Furthermore, the Myb core, AACGG, was characterized as necessary for the binding of proteins. DNA affinity purification of the complexes bound to the 18 bp sequence allowed the isolation of three different complexes and two proteins from these complexes were identified by mass spectrometry analyses. A new putative Myb transcription factor and a hypothetical protein, HYP containing with a leucine zipper and Myc-type dimerization domains were identified. When over-expressed in plants, HYP factor is able to trans-activate the expression of gus reporter gene downstream from the -202 promoter fragment as well as the endogenous CycB1;1 gene. PMID: 12139003 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 50: Oncogene. 2002 May 2;21(19):3076-81. Targeted disruption of c-myb in the chicken pre B-cell line DT40. Appl H, Klempnauer KH. Institut fur Biochemie, Westfalische-Wilhelms-Universitat Munster, Wilhelm-Klemm-Str. 2, D-48143 Munster, Germany. The c-myb proto-oncogene is highly expressed in a wide variety of immature hematopoietic cells and plays a key role in the development of the hematopoietic system. c-myb and its retroviral counterpart v-myb encode transcription factors which have been implicated in the regulation of certain target genes. Targeting of c-myb in mouse embryonic stem cells by homologous recombination has provided clear evidence that c-myb is necessary for the proper development of most myeloid lineages of the hematopoietic system as well as of T-lymphocytes. Here we have explored the function of c-myb in the B-lymphoid lineage. We have used the chicken DT40 cells, a pre B-cell line which shows extremely high efficiencies of homologous recombination, as a model system to disrupt c-myb. DT40 cells lacking a functional c-myb gene are viable and show only minor perturbations of their growth parameters, indicating that c-myb is not an essential gene in these cells. We have used the c-myb null DT40 cells to analyse the expression of genes which have been previously been identified as myb target genes. Neither c-myc nor bcl-2, two putative myb targets, showed altered expression in the cells lacking c-myb. However, expression of the Pdcd4 gene, a myb target gene originally identified in a myelomonocytic cell line expressing a conditional form of v-myb, was diminished in the absence of c-myb. The c-myb knock-out cells described here should provide a useful model system for the identification and characterization of c-myb target genes in B-lymphoid cells. PMID: 12082539 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 51: Oral Oncol. 2002 Jun;38(4):357-63. Genetic alterations in squamous cell carcinomas of the hypopharynx with correlations to clinicopathological features. Rodrigo JP, Gonzalez MV, Lazo PS, Ramos S, Coto E, Alvarez I, Garcia LA, Suarez C. Department of Otolaryngology, Hospital Central de Asturias, University of Oviedo, Instituto Universitario de Oncologia, Oviedo, Spain. jrodrigo@hcas.insalud.es The objective of this study is to describe the molecular alterations in carcinomas in one specific location of the head and neck, the hypopharynx. Thirty-seven hypopharyngeal squamous cell carcinomas were studied. The DNA from tumour and healthy tissue was evaluated for amplification of the 11q13 region and of the MYC and ERBB1 oncogenes, for integration of the Human Papillomavirus (HPV), and for loss of heterozygosity (LOH) at p53 and NAT2 loci.The most common alteration was the amplification of the 11q13 region (78% of the cases), followed by LOH at p53 locus (70%). MYC amplification was found in 19% of the cases, ERBB1 amplification in 29%, LOH at NAT2 locus in 25%, and integration of the HPV in 29%. 11q13 amplification was related with nodal metastases and higher tumour recurrence rates. These findings confirm that 11q13 amplification is one of the most frequent genetic alterations in hypopharyngeal squamous cell carcinomas, and that it may have prognostic significance in these tumours. PMID: 12076699 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 52: Int J Radiat Oncol Biol Phys. 2002 May 1;53(1):180-9. Activation of the nuclear transcription factor kappaB (NFkappaB) and differential gene expression in U87 glioma cells after exposure to the cytoprotector amifostine. Kataoka Y, Murley JS, Khodarev NN, Weichselbaum RR, Grdina DJ. Department of Radiation and Cellular Oncology, University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, USA. PURPOSE: Amifostine has been approved as a therapy to decrease the incidence of moderate-to-severe xerostomia in patients undergoing postoperative radiation treatment for head-and-neck cancer. As a reducing agent capable of participating in intracellular reductive/oxidative processes, it has the potential to affect redox-sensitive transcription factors and gene expression. Amifostine's active free thiol WR-1065 was investigated to determine its effect on nuclear transcription factor kappaB (NFkappaB) activation and subsequent gene expression in U87 glioma cells. METHODS AND MATERIALS: The human glioma cell line U87 was grown to confluency and then exposed to WR-1065 at a concentration of 40 microM for times ranging from 30 min to 24 h. Changes in cell cycle were monitored by flow cytometry. The effect of WR-1065 on NFkappaB activation was determined by a gel shift assay. Changes in gene expression as a function of time of exposure to WR-1065 were determined by Northern blot and the Atlas Human cDNA Expression Array (Clontech, Palo Alto, CA). Changes in gene expression using the Atlas Array were verified by reverse transcriptase-polymerase chain reaction (RT-PCR) with gene-specific primers. RESULTS: Exposure of U87 cells to 40 microM WR-1065 resulted in a marked activation of NFkappaB between 30 min and 1 h after treatment. Expression of MnSOD, an NFkappaB-responsive gene, was enhanced by over 2-fold after 16 h of treatment and remained elevated at 24 h. During this period of time, no changes in cell cycle distribution were observed. To assess changes in the expression levels of NFkappaB-responsive genes as a function of WR-1065 exposure, cDNA arrays containing 49 genes identified as having DNA-binding motifs for NFkappaB were used. Only five genes were found to be significantly affected at 1, 4, and/or 16 h of treatment. GST-3 and c-myc were repressed up to 2- and 4-fold, respectively. The expression levels of IL-2Ra, RANTES, and c-myb, in contrast, were enhanced up to 14-, 3-, and 2-fold, respectively. The remaining genes having NFkappaB-responsive elements in their promoter regions were either not expressed (20 genes) or were not affected (24 genes) by exposure to WR-1065. CONCLUSIONS: The redox-sensitive transcription factor NFkappaB can be activated in U87 glioma cells by the active thiol form of the cytoprotector amifostine. Activation of NFkappaB by the antioxidant WR-1065 is accompanied by a reduced expression of the oncogene c-myc and an enhanced expression of the antioxidant gene MnSOD, a gene whose expression in tumor cells is relatively low, but when overexpressed has been correlated with a suppression of the malignant phenotype. Activation of NFkappaB by WR-1065, however, results in selective rather than global changes in the expression of genes containing NFkappaB-responsive elements. PMID: 12007958 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 53: J Neurotrauma. 2002 Mar;19(3):379-85. Expression of c-Fos and c-Myc and deposition of beta-APP in neurons in the adult rat brain as a result of exposure to short-lasting impulse noise. Saljo A, Bao F, Shi J, Hamberger A, Hansson HA, Haglid KG. Department of Anatomy and Cell Biology, University of Goteborg, Sweden. annette.saljo@anatcell.gu.se There is increasing evidence that impulse noise causes brain damage, but little is known about the mechanisms and extent of the response. Here, rat brains were investigated immunohistochemically for the expression of c-Fos, c-Myc, and beta-APP during the first 3 weeks postexposure to impulse noise of 198 or 202 dB. The expression of c-Fos and c-Myc increased at 2 h after exposure in neurons of the cerebral cortex, thalamus, and hippocampus, and this c-Fos immunoreactivity remained elevated for the entire observation period. The c-Myc immunoreactivity peaked at 18 h in both neurons and astrocytes but returned to control levels at 7 days. Abnormal deposition of beta-APP was evident within 6 h in the same brain regions. The beta-APP immunoreactivity was most prominent at 18 h and remained increased over the 21-day period assessed. The observed effects were similar to those described in humans following traumatic brain injury and in Alzheimer's disease. We conclude that impulse noise influences the brain in a fashion similar to that in cases with progressive CNS degeneration. PMID: 11939505 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 54: Oncogene. 2002 Mar 14;21(12):1859-69. A Myb dependent pathway maintains Friend murine erythroleukemia cells in an immature and proliferating state. Chen J, Kremer CS, Bender TP. Department of Molecular Physiology, University of Virginia Health System, PO Box 800734, Charlottesville, Virginia, VA 22908-0734, USA. Friend murine erythroleukemia (MEL) cells are transformed erythroid precursors that are held in an immature and proliferating state but can be induced to differentiate in vivo by treatment with a variety of chemical agents such as N, N-hexamethylene bisacetamide (HMBA). To investigate the role of Myb proteins in maintaining MEL cells in an immature and proliferating state we have produced stable transfectants in the C19 MEL cell line that contain a dominant interfering Myb allele (MEnT) under the control of an inducible mouse metallothionein I promoter. When expression of MEnT protein was induced with ZnCl2, the stable transfectants differentiated with kinetics that were similar to wild type C19 MEL cells treated with HMBA, including induction of alpha-globin mRNA expression, assembly of hemoglobin and growth arrest. Expression of endogenous c-myb and c-myc was also decreased in response to MEnT. Expression of mad-1 mRNA was rapidly increased in response to expression of MEnT resulting in a shift from predominantly c-Myc/Max complexes to predominantly Mad/Max containing complexes. These results strongly suggest that C19 MEL cells are held in an immature and proliferating state by a pathway that is dependent on Myb activity. PMID: 11896618 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 55: Anticancer Res. 2001 Sep-Oct;21(5):3185-92. Activation of c-MYC and c-MYB proto-oncogenes is associated with decreased apoptosis in tumor colon progression. Greco C, Alvino S, Buglioni S, Assisi D, Lapenta R, Grassi A, Stigliano V, Mottolese M, Casale V. Clinical Pathology Service, Regina Elena Cancer Institute, Rome, Italy. ayyctg@tin.it BACKGROUND: An increasing amount of evidence suggests that progression from normal mucosa to colorectal cancer is accompanied by morphological and genetic alterations. Genetic abnormalities affect malignant transformation via a gradual imbalance of normal tissue homeostasis involving programmed cell death (PCD) or apoptosis. Therefore, it has been hypothesized that alterations in apoptosis may contribute to carcinogenesis. The aim of the present work was to investigate the relationship between frequency of spontaneous apoptosis during transition adenoma-to-carcinoma of the colorectal tract and the incidence of activation of c-myc and c-myb proto-oncogenes, involved both in colon tumorigenesis and apoptosis. MATERIALS AND METHODS: Ninety-five tissue specimens (60 polyps and 35 adenocarcinomas) were removed with autologous normal adjacent mucosa from colon cancer patients. Genomic DNA was extracted and analyzed for both apoptosis frequency (DNA fragmentation assay) and proto-oncogene activation (Southern blot analysis). On the same samples, Bcl-2 protein expression was evaluated by immunohistochemistry. RESULTS: Our results showed that: i) a significant relationship exists between apoptosis and genesis of colorectal cancer since, compared to adenomatous polyps and adjacent normal mucosa, cell death is markedly inhibited in tumors (p = 0.01); ii) during colon tumor progression, apoptosis and amplifications of c-myc/c-myb genes are inversely related; iii) Bcl-2 expression is retained in colon tumors even though at a significantly lower level with respect to adenomatous polyps. CONCLUSION: These results indicate that failure of the normal apoptotic process together with de-regulation of c-myc and c-myb proto-oncogenes might promote the development of colorectal tumors. PMID: 11848471 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 56: Plant Cell Physiol. 2002 Jan;43(1):58-69. The APRR1/TOC1 quintet implicated in circadian rhythms of Arabidopsis thaliana: I. Characterization with APRR1-overexpressing plants. Makino S, Matsushika A, Kojima M, Yamashino T, Mizuno T. Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan. Several Arabidopsis genes have been proposed to encode potential clock-associated components, including the Myb-related CCA1 and LHY transcription factors and a member of the novel family of pseudo response regulators (APRR1/TOC1). We previously showed that mRNAs of the APRR1/TOC1 family of genes start accumulating after dawn rhythmically and sequentially at approximately 2 h intervals in the order: APRR9--> APRR7-->APRR5-->APRR3-->APRR1/TOC1. Here we constructed APRR1-overexpressing (APRR1-ox) plants, and examined certain circadian profiles for APRRs, CCA1, LHY, GI, CCR2, and CAB2. The free-running circadian rhythms of the APRR1/TOC1 family of genes, including APRR1, were dampened in APRR1-ox plants. In particular, the light-inducible expression of APRR9 was severely repressed in APRR1-ox plants, suggesting that there is a negative APRR1-->APRR9 regulation. The free-running robust rhythm of CAB2 was also dampened in APRR1-ox. The circadian profiles of potential clock-associated genes, CCA1, LHY, GI, and CCR2 were all markedly altered in APRR1-ox, each in characteristic fashion. To gain further insight into the molecular function of APRR1, we then identified a novel Myc-related bHLH transcription factor, which physically associated with APRR1. This protein (named PIL1) is similar in its amino acid sequence to PIF3, which has been identified as a phytochrome-interacting transcription factor. These results are discussed in relation to the current idea that APRR1 (TOC1) plays a role within, or close to, the Arabidopsis central oscillator. PMID: 11828023 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 57: Cell. 2002 Jan 11;108(1):57-70. Mechanism of c-Myb-C/EBP beta cooperation from separated sites on a promoter. Tahirov TH, Sato K, Ichikawa-Iwata E, Sasaki M, Inoue-Bungo T, Shiina M, Kimura K, Takata S, Fujikawa A, Morii H, Kumasaka T, Yamamoto M, Ishii S, Ogata K. Kanagawa Academy of Science and Technology, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan. tahir@med.yokohama-cu.ac.jp c-Myb, but not avian myeloblastosis virus (AMV) v-Myb, cooperates with C/EBP beta to regulate transcription of myeloid-specific genes. To assess the structural basis for that difference, we determined the crystal structures of complexes comprised of the c-Myb or AMV v-Myb DNA-binding domain (DBD), the C/EBP beta DBD, and a promoter DNA fragment. Within the c-Myb complex, a DNA-bound C/EBP beta interacts with R2 of c-Myb bound to a different DNA fragment; point mutations in v-Myb R2 eliminate such interaction within the v-Myb complex. GST pull-down assays, luciferase trans-activation assays, and atomic force microscopy confirmed that the interaction of c-Myb and C/EBP beta observed in crystal mimics their long range interaction on the promoter, which is accompanied by intervening DNA looping. PMID: 11792321 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 58: 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] --------------------------------------------------------------- 59: Hypertension. 2001 Nov;38(5):1210-6. Gene therapy for cardiovascular disease: a case for cautious optimism. Khurana R, Martin JF, Zachary I. Center for Cardiovascular Biology and Medicine, Department of Medicine, University College London, London, United Kingdom. There is currently intense interest in the development of gene therapy for cardiovascular disease. The stimulation of therapeutic angiogenesis for ischemic heart disease has been one of the areas of greatest promise. Encouraging results have been obtained with the angiogenic cytokines vascular endothelial growth factor (VEGF) and basic fibroblast growth factor in animal models, leading to clinical trials in ischemic heart disease. VEGF also has therapeutic potential in a second area of cardiovascular gene therapy, the enhancement of arterioprotective endothelial functions to prevent postangioplasty restenosis and bypass graft arteriopathy. The endothelial cell growth and survival functions of VEGF promote endothelial regeneration, whereas VEGF-induced endothelial production of NO and prostacyclin inhibits vascular smooth muscle cell proliferation. Inhibition of neointimal hyperplasia may also be achieved by gene transfer of endothelial NO synthase (eNOS), PGI synthase, or cell cycle regulators (retinoblastoma, cyclin or cyclin-dependent kinase inhibitors, p53, growth arrest homeobox gene, fas ligand) or antisense oligonucleotides to c-myb, c-myc, proliferating cell nuclear antigen, and transcription factors such as nuclear factor kappaB and E2F. An improved understanding of etiologically complex pathologies involving the interplay of genes and the environment, such as atherosclerosis and systemic hypertension, has led to the identification of new targets for gene therapy, with the potential to alleviate inherited genetic defects such as familial hypercholesterolemia. The use of vasodilator gene overexpression and antisense knockdown of vasoconstrictors to reduce blood pressure in animal models of systemic and pulmonary hypertension offers the prospect of gene therapy for human hypertensive disease. The renin-angiotensin system has been the target of choice for antihypertensive strategies because of its wide distribution and additional effects on fibrinolytic and oxidative stress pathways. Gene therapy in cardiovascular disease has an exciting future but remains at an early stage. Further developments in gene transfer vector technology and the identification of additional target genes will be required before its full therapeutic potential can be realized. Publication Types: Review Review, Tutorial PMID: 11711525 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 60: Oncogene. 2001 Sep 27;20(43):6205-14. Deregulated c-Myb expression in murine myeloid leukemias prevents the up-regulation of p15(INK4b) normally associated with differentiation. Schmidt M, Koller R, Haviernik P, Bies J, Maciag K, Wolff L. Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, MD, USA. Deregulated expression of the proto-oncogene c-myb, which results from provirus integration, is thought to be responsible for transformation in a set of murine leukemia virus (MuLV)-induced myeloid leukemias (MML). We reported recently that this transcription factor promotes proliferation by directly transactivating c-myc and inhibits cell death through its up-regulation of Bcl-2 (Schmidt et al., 2000). To understand more about how these cells become transformed we looked at how they deal with cellular pathways inducing growth arrest. Specifically, we were interested in the expression of the tumor suppressor gene Cdkn2b (p15(INK4b)) in MML because this gene is expressed during myeloid differentiation and its inactivation by methylation has been shown to be important for the development of human acute myeloid leukemia. mRNA levels for p15(INK4b) and another INK4 gene p16(INK4a) were examined in monocytic Myb tumors and were compared with expression of the same genes in c-myc transformed monocytic tumors that do not express c-Myb. The Cdkn2a (p16(INK4a)) gene was generally not expressed in either tumor type, an observation explained by methylation or deletion in the promoter region. Although Cdkn2b (p15(INK4b)) mRNA was expressed in the Myc tumors, many transcripts were aberrant in size and contained only exon 1. Surprisingly, in the majority of the Myb tumors there was no p15(INK4b) transcription and neither deletion nor methylation could explain this result. Additional experiments demonstrated that, in the presence of constitutive c-Myb expression, the induction of p15(INK4b) mRNA that accompanies differentiation of M1 cells to monocytes does not occur. Therefore, the transcriptional regulator c-Myb appears to prevent activation of a growth arrest pathway that normally accompanies monocyte maturation. PMID: 11593429 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 61: Mol Carcinog. 2001 Sep;32(1):28-35. Gene expression profile in BALB/c-3T3 cells transformed with beryllium sulfate. Joseph P, Muchnok T, Ong T. Molecular Epidemiology Laboratory, Toxicology and Molecular Biology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA. Differential gene expression was studied to understand the potential molecular mechanism responsible for cell transformation and tumorigenesis induced by beryllium. Cell lines were derived from tumors developed in nude mice injected subcutaneously with BALB/c-3T3 cells morphologically transformed with beryllium sulfate. Using the Atlas mouse 1.2 cDNA expression microarray, the expression profiles of 1176 genes, belonging to several different functional categories, were studied in the tumor cells as well as in the nontransformed control cells. Expression of 18 genes belonging to two functional groups was found to be consistently and reproducibly different (at least twofold) in the tumor cells compared with the control cells. The functional groups and the differentially expressed genes are as follows: The cancer-related genes (nine genes) were the ets-related transcription factor activated by ras, colony-stimulating factor, A-myb, sky, cot1, c-fos, c-jun, c-myc, and R-ras proto-oncogenes. The DNA synthesis, repair, and recombination genes (nine genes) were the DNA replication licensing factor MCM4, the DNA replication licensing factor MCM5, the DNA mismatch repair gene PMS2, the DNA excision repair gene, the DNA mismatch repair gene MSH2, the ultraviolet excision repair gene Rad23 DNA ligase 1, Rad51, and Rad52. The differential gene expression profile was confirmed with reverse transcription-polymerase chain reaction using primers specific for the differentially expressed genes. In general, expression of the cancer-related genes was upregulated, while expression of genes involved in DNA synthesis, repair, and recombination was downregulated in the tumor cells compared with the control cells. Using c-fos and c-jun, two of the differentially expressed genes, as model genes, we have found that in the nontransformed BALB/c-3T3 cells, the beryllium-induced transcriptional activation of these genes was dependent on pathways of protein kinase C and mitogen-activated protein kinase and independent of reactive oxygen species. These results indicate that beryllium-induced cell transformation and tumorigenesis are accompanied by and are possibly a product of alterations in expression of genes related to cancer and to DNA synthesis, repair, and recombination. Copyright 2001 Wiley-Liss, Inc. PMID: 11568973 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 62: J Control Release. 2001 Jul 6;74(1-3):69-75. Targeted delivery of antisense oligonucleotides in cancer. Pastorino F, Stuart D, Ponzoni M, Allen TM. Department of Pharmacology 9-31 MSB, University of Alberta, Edmonton, Alberta T6G 2H7, Canada. Formulations of antisense oligonucleotides (asODNs) against c-myb or c-myc protooncogenes have been prepared by a new technique that sequesters cationic lipid in the interior of a lipid particle. This technique results in high loading efficiency for the asODNs, small particle size and good stability. When targeted against melanoma cells or neuroblastoma cells via anti-GD(2) coupled at the particle surface, increased cell binding to the cells could be demonstrated. Targeted formulations showed greater inhibition of cell proliferation compared to non-targeted formulations or free drug. Inhibition of cell proliferation was demonstrated to be due to down-regulation of c-myb or c-myc protein expression. The formulations have long-circulation times in vivo, and evaluation for in vivo antitumor activity is currently underway. PMID: 11489484 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 63: Mol Cell Biol. 2001 Sep;21(17):5797-805. c-Myb transcription is activated by protein kinase B (PKB) following interleukin 2 stimulation of Tcells and is required for PKB-mediated protection from apoptosis. Lauder A, Castellanos A, Weston K. CRC Centre for Cell and Molecular Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, United Kingdom. During T-cell activation, c-Myb is induced upon interleukin 2 (IL-2) stimulation and is required for correct proliferation of cells. In this paper, we provide evidence that IL-2-mediated induction of the c-myb gene occurs via the phosphoinositide 3-kinase (PI3K) signaling pathway, that protein kinase B (PKB) is the principal transducer of this signal, and that activation of the c-myb promoter can be abolished by deletion of conserved E2F and NF-kappaB binding sites. We show that Myb is required to protect activated peripheral T cells from bcl-2-independent apoptosis and that overexpression of oncogenic v-Myb is antiapoptotic. Overexpression of a Myb dominant-negative transgene abrogates PKB-mediated protection from apoptosis. Taken together, these results suggest that induction of c-myb transcription is an important downstream event for PKB-mediated protection of T cells from programmed cell death. PMID: 11486019 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 64: 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] --------------------------------------------------------------- 65: Nat Immunol. 2001 Aug;2(8):698-704. Transcription factor LKLF is sufficient to program T cell quiescence via a c-Myc--dependent pathway. Buckley AF, Kuo CT, Leiden JM. Committee on Immunology, University of Chicago, Chicago, IL 60637, USA. T lymphocytes circulate in a quiescent state until they encounter cognate antigen bound to the surface of an antigen-presenting cell. The molecular pathways that regulate T cell quiescence remain largely unknown. Here we show that forced expression of the lung Kruppel-like transcription factor (LKLF) in Jurkat T cells is sufficient to program a quiescent phenotype characterized by decreased proliferation, reduced cell size and protein synthesis and decreased surface expression of activation markers. Conversely, LKLF-deficient peripheral T cells produced by gene targeting showed increased proliferation, increased cell size and enhanced expression of surface activation markers in vivo. LKLF appeared to function, at least in part, by decreasing expression of the proto-oncogene encoding c-Myc. Forced expression of LKLF was associated with markedly decreased c-Myc expression. In addition, many effects of LKLF expression were mimicked by expression of the dominant-negative MadMyc protein and rescued by overexpression of c-Myc. Thus, LKLF is both necessary and sufficient to program quiescence in T cells and functions, in part, by negatively regulating a c-Myc--dependent pathway. PMID: 11477405 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 66: Oncogene. 2001 Jun 21;20(28):3674-82. Distinctive gene expression profiles associated with Hepatitis B virus x protein. Wu CG, Salvay DM, Forgues M, Valerie K, Farnsworth J, Markin RS, Wang XW. Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, Maryland, MD 20892-4255, USA. Hepatitis B virus (HBV) is a major risk factor for the development of hepatocellular carcinoma (HCC). HBV encodes the potentially oncogenic HBx protein, which mainly functions as a transcriptional co-activator involving in multiple gene deregulations. However, mechanisms underlying HBx-mediated oncogenicity remain unclear. To determine the role(s) of HBx in the early genesis of HCC, we utilized the NCI Oncochip microarray that contains 2208 human cDNA clones to examine the gene expression profiles in either freshly isolated normal primary adult human hepatocytes (Hhep) or an HCC cell line (SK-Hep-1) ecotopically expressing HBx via an adenoviral system. The gene expression profiles also were determined in liver samples from HBV-infected chronic active hepatitis patients when compared with normal liver samples. The microarray results were validated through Northern blot analysis of the expression of selected genes. Using reciprocally labeling hybridizations, scatterplot analysis of gene expression ratios in human primary hepatocytes expressing HBx demonstrates that microarrays are highly reproducible. The comparison of gene expression profiles between HBx-expressing primary hepatocytes and HBV-infected liver samples shows a consistent alteration of many cellular genes including a subset of oncogenes (such as c-myc and c-myb) and tumor suppressor genes (such as APC, p53, WAF1 and WT1). Furthermore, clustering algorithm analysis showed distinctive gene expression profiles in Hhep and SK-Hep-1 cells. Our findings are consistent with the hypothesis that the deregulation of cellular genes by oncogenic HBx may be an early event that favors hepatocyte proliferation during liver carcinogenesis. PMID: 11439330 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 67: Blood. 2001 May 15;97(10):3259-67. Short-chain fatty acid derivatives stimulate cell proliferation and induce STAT-5 activation. Boosalis MS, Bandyopadhyay R, Bresnick EH, Pace BS, Van DeMark K, Zhang B, Faller DV, Perrine SP. Department of Medicine, Cancer Research Center and Hemoglobinopathy-Thalassemia Research Unit, Boston University School of Medicine, Boston, MA, USA. Current chemotherapeutic and butyrate therapeutics that induce fetal hemoglobin expression generally also suppress erythropoiesis, limiting the production of cells containing fetal hemoglobin (F cells). Recently, selected short-chain fatty acid derivatives (SCFADs) were identified that induce endogenous gamma-globin expression in K562 cells and human burst-forming units-erythroid and that increase proliferation of human erythroid progenitors and a multilineage interleukin-3-dependent hematopoietic cell line. In this report, gamma-globin inducibility by these SCFADs was further demonstrated in mice transgenic for the locus control region and the entire beta-globin gene locus in a yeast artificial chromosome and in 2 globin promoter-reporter assays. Conditioned media experiments strongly suggest that their proliferative activity is a direct effect of the test compounds. Investigation of potential mechanisms of action of these SCFADs demonstrates that these compounds induce prolonged expression of the growth-promoting genes c-myb and c-myc. Both butyrate and specific growth-stimulatory SCFADs induced prolonged signal transducer and activator of transcription (STAT)-5 phosphorylation and activation, and c-cis expression, persisting for more than 120 minutes, whereas with IL-3 alone phosphorylation disappeared within minutes. In contrast to butyrate treatment, the growth-stimulating SCFADs did not result in bulk histone H4 hyperacetylation or induction of p21(Waf/Cip), which mediates the suppression of cellular growth by butyrate. These findings suggest that the absence of bulk histone hyperacetylation and p21 induction, but prolonged induction of cis, myb, myc, and STAT-5 activation, contribute to the cellular proliferation induced by selected SCFADs. PMID: 11342457 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 68: Int J Biochem Cell Biol. 2001 Apr;33(4):391-407. The Ets family contains transcriptional activators and repressors involved in angiogenesis. Lelievre E, Lionneton F, Soncin F, Vandenbunder B. Institut de Biologie de Lille, 1, rue du Professeur Calmette, BP 447, 59021, Lille Cedex, France. The Ets family contains a growing number of transcriptional activators and inhibitors, which activity is regulated by phosphorylation and protein-protein interactions. Among these factors, Ets1, Erg1 and Fli1 are expressed in endothelial cells during angiogenesis in normal and pathological development. The expression of these transcription factors is regulated by angiogenic factors in cultured endothelial cells, as well as by various stresses occurring during angiogenesis. Transfection experiments and transgenic mice analysis revealed that Ets family members are involved in the transcriptional regulation of endothelial specific genes such as those encoding Tie1 and -2, VEGFR1 and -2 and VE-Cadherin. In vitro studies plead for a role of Ets family members in endothelial cell adhesion, spreading and motility. Gene inactivation experiments show that Ets1 is dispensable for embryonic development. The phenotype of knocked-out embryos indicates that Tel is required for maintenance of the developing vascular network in the yolk sac. Altogether, we suggest that Ets family members act both positively and negatively during the different steps of the angiogenic process. The regulation of the initiation of gene transcription arises from the combined activity of different transcriptional regulators. Therefore very few transcription factors are specific for a physiological process, or a given cell type. The transcriptional network that regulates blood vessel formation involves transcription factors which are expressed in a variety of situations. The Lung Kruppel Like Factor (LKLF) which is required for blood vessel stabilisation during murine development is also expressed in the primitive vertebrae and in the lung of the adult (C.T. Kuo, M.L. Veselits, K.P. Barton, M.M. Lu, C. Clendenin, J.M. Leiden, The LKLF transcription factor is required for normal tunica media formation and blood vessel stabilisation during murine embryogenesis, Genes Dev. 11 (22) (1997) 2996-3006). Scl/Tal1 which is essential for angiogenic remodelling of the yolk sac capillary network (J.E. Visvader, Y. Fujiwara, S.H. Orkin, Unsuspected role for the T-cell leukemia protein SCL/tal-1 in vascular development, Genes Dev. 12 (4) (1998) 473-479), is involved in blood cell development and is also expressed in the developing brain. The EPAS transcription factor which was thought to be endothelial cell specific in the mouse embryo (H. Tian, S.L. McKnight, D.W. Russell, Endothelial PAS domain protein 1 (EPAS1), a transcription factor selectively expressed in endothelial cells, Genes Dev. 11 (1) (1997) 72-82) is also expressed in the liver, kidney and cells of the sympathetic nervous system of the chick embryo (J. Favier, H. Kempf, P. Corvol, J.M. Gasc, Cloning and expression pattern of EPAS1 in the chicken embryo. Colocalization with tyrosine hydroxylase, FEBS Lett. 462 (1-2) (1999) 19-24). Ets1, which expression was originally detected in lymphoid cells of adult tissues, has been the first transcription factor to be identified in endothelial cells during angiogenesis in the embryo (B. Vandenbunder, L. Pardanaud, T. Jaffredo, M.A. Mirabel, D. Stehelin, Complementary patterns of expression of c-etsl, c-myb and c-myc in the blood-forming system of the chick embryo, Development 107 (1989) 265-274 [5]) and in tumours (N. Wernert, M.B. Raes, P. Lassalle, M.P. Dehouck, B. Gosselin, B. Vandenbunder, D. Stehelin, The c-ets 1 proto-oncogene is a transcription factor expressed in endothelial cells during tumor vascularisation and other forms of angiogenesis in man, Am. J. Path. 140 (1992) 119-127 [6]). Since then, the Ets family has extended and this review will emphasise the relationships between these factors and angiogenesis. Publication Types: Review Review, Tutorial PMID: 11312108 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 69: Ann Rheum Dis. 2001 May;60(5):433-41. Cancer and autoimmunity: autoimmune and rheumatic features in patients with malignancies. Abu-Shakra M, Buskila D, Ehrenfeld M, Conrad K, Shoenfeld Y. Department of Medicine and Rheumatic Diseases Unit, Soroka Medical Centre, and Ben-Gurion University, Beer-Sheva, Israel. OBJECTIVES: To review the autoimmune and rheumatic manifestations of patients with malignancy. METHODS: A Medline search of all published papers using keywords related to malignancies, autoimmunity, rheumatic diseases, and paraneoplastic syndromes. RESULTS: Patients with malignant diseases may develop autoimmune phenomena and rheumatic diseases as a result of (a) generation of autoantibodies against various autoantigens, including oncoproteins (P185, 1-myc, c-myc, c-myb), tumour suppression genes (P53), proliferation associated antigens (cyclin A, B1, D1, E; CENP-F; CDK, U3-RNP), onconeural antigens (Hu, Yo, Ri, Tr), cancer/testis antigens (MAGE, GAGE, BAGE, SSX, ESO, SCP, CT7), and rheumatic disease associated antigens (RNP, Sm). The clinical significance of the various autoantibodies is not clear. Anti-oncoprotein and anti-tumour suppression gene antigens are detected before the diagnosis of the cancer or in the early stages of the malignant disease, suggesting a potential diagnostic or prognostic role. Anti-onconeural antibodies are pathogenic and are associated with specific clinical neurological syndromes (anti-Hu syndrome and others). (b) Paraneoplastic syndromes, a wide range of clinical syndromes, including classic autoimmune rheumatic diseases that develop among patients with cancer. (c) Rheumatism after chemotherapy, a clinical entity characterised by the development of musculoskeletal symptoms after combination chemotherapy for malignancy. CONCLUSION: Autoimmune and rheumatic features are not rare among patients with malignancies. They are the result of various diverse mechanisms and occasionally they may be associated with serious clinical entities. Publication Types: Review Review, Tutorial PMID: 11302861 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 70: Blood Cells Mol Dis. 2001 Mar-Apr;27(2):483-8. Three genes with different functions in transformation are regulated by c-Myb in myeloid cells. Wolff L, Schmidt M, Koller R, Haviernik P, Watson R, Bies J, Maciag K. Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, Maryland 20892-4255, USA. lwolff@helix.nih.gov The proto-oncogene c-myb is constitutively expressed in murine leukemia virus-induced myeloid leukemia (MML) due to the integration of virus at this locus. Our recent focus has been the determination of genes regulated by this transcription factor that may be involved in transformation. Data presented here, using conditional expression of Myb in myeloid cells, show that c-Myb directly transactivates the endogenous c-myc and Bcl-2 genes, which explains at least in part how c-Myb regulates proliferation and survival. In addition, c-Myb prevents expression at the RNA level of the tumor suppressor INK4b gene. This gene encodes a cyclin-dependent kinase inhibitor, p15INK4b, that is normally upregulated at the mRNA level during myeloid differentiation and promotes growth arrest. The MMLs are generally characterized as differentiated monocytic tumors and possess the phenotype that is normally associated with p15INK4b expression. c-Myb inhibits expression of this gene, however, and therefore acts to promote a pathway which is abnormal in mature cells. This activity of c-Myb collaborates with its maintenance of c-myc expression to promote growth. Copyright 2001 Academic Press. PMID: 11259171 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 71: Blood Cells Mol Dis. 2001 Mar-Apr;27(2):409-15. Identification and validation of candidate Myb target genes. Bartley PA, Lutwyche JK, Gonda TJ. Hanson Centre for Cancer Research, Division of Human Immunology, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA, 5000, Australia. While a considerable number of candidate Myb target genes have been reported to date, most of these are likely to play little or no role in transformation by myb oncogenes. Here we have used a conditionally myb-transformed myeloid cell line (ERMYB) to further examine Myb regulation of one candidate target gene--c-myc--that has the potential to affect cell proliferation. It was found that the major influence on c-myc expression was the presence of cytokine (GM-CSF) rather than Myb activity. We also describe the application of PCR-based subtractive hybridization and low-density cDNA array screening, in conjunction with the ERMYB line, to the identification of additional Myb target genes. Preliminary identification of a number of candidates is reported; these include myeloperoxidase, which is known to have essential Myb-binding sites in its regulatory region. Copyright 2001 Academic Press. PMID: 11259163 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 72: Cancer Res. 2001 Feb 1;61(3):1073-9. Inhibition of N-myc expression and induction of apoptosis by iron chelation in human neuroblastoma cells. Fan L, Iyer J, Zhu S, Frick KK, Wada RK, Eskenazi AE, Berg PE, Ikegaki N, Kennett RH, Frantz CN. Department of Pediatrics and the Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore 21201, USA. Neuroblastoma is the second most common solid malignancy of childhood. Enhanced expression of the amplified N-myc gene in the tumor cells may be associated with poor patient prognosis and may contribute to tumor development and progression. The use of deferoxamine mesylate (DFO), an iron chelator, to treat neuroblastoma is being investigated in national clinical studies. We show here by TUNEL assay and DNA laddering that DFO induces apoptosis in cultured human neuroblastoma cells, which is preceded by a decrease in the expression of N-myc and the altered expression of some other oncogenes (up-regulating c-fos and down-regulating c-myb) but not housekeeping genes. The decrease in N-myc expression is iron-specific but does not result from inhibition of ribonucleotide reductase, because specific inhibition of this iron-containing enzyme by hydroxyurea does not affect N-myc protein levels. Nuclear run-on and transient reporter gene expression experiments show that the decrease in N-myc expression occurs at the level of initiation of transcription and by inhibiting N-myc promoter activity. Comparison across neuroblastoma cell lines of the amount of residual cellular N-myc protein with the extent of apoptosis measured as pan-caspase activity after 48 h of iron chelation reveals no correlation, suggesting that the decrease in N-myc expression is unlikely to mediate apoptosis. In conclusion, chelation of cellular iron by DFO may alter the expression of multiple genes affecting the malignant phenotype by multiple pathways. Given the clinical importance of N-myc overexpression in neuroblastoma malignancy, decreasing N-myc expression by DFO might be useful as an adjunct to current PMID: 11221835 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 73: Oncogene. 2000 Jul 27;19(32):3684-92. Pim-1 kinase protects hematopoietic FDC cells from genotoxin-induced death. Pircher TJ, Zhao S, Geiger JN, Joneja B, Wojchowski DM. Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park 16802, USA. The hematopoietic cell S/T kinase Pim-1 was originally discovered as a target of murine leukemia provirus integration, and when expressed at increased levels is predisposing to lymphomagenesis. Recently, Pim-1 has been shown to enhance the activities of p100, c-Myb and cdc25a, and in part this might explain reported effects on mitogenesis. In the context of cytokine withdrawal, Pim-1 also can attenuate programmed cell death (PCD). Cytokine withdrawal, however, alters signaling pathways and can complicate the dissection of mitogenic vs apoptotic responses. To better study possible effects of Pim-1 on PCD, a hematopoietic cell model was developed in which proliferation was supported efficiently by SCF plus EPO in the absence of endogenous Pim-1 gene expression. This was provided by factor-dependent FDCW2 cells that express endogenous and functional c-Kit, and were transfected stably with truncated Epo receptor form mutated at a Y343 STAT5 binding site. In proliferating cells, exogenously expressed Pim-1 was observed to efficiently inhibit PCD as induced by either Co60 or adriamycin, and the dose-dependent nature of this effect was established in several independent clones. By comparison, effects of exogenous Pim-1 on mitogenesis were nominal. In addition, in cell fractionation studies an estimated 25% of Mr 34000 Pim-1 (but not Mr 44000 Pim-1) was present in nuclear extracts. Thus, Pim-1 efficiently buffers hematopoietic progenitor cells against death as induced by several clinically important apoptotic agents, and may directly target nuclear effectors. PMID: 10951575 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 74: Blood. 2000 Aug 1;96(3):1013-20. A-myb rescues murine B-cell lymphomas from IgM-receptor-mediated apoptosis through c-myc transcriptional regulation. Arsura M, Hofmann CS, Golay J, Introna M, Sonenshein GE. Department of Biochemistry, Boston University School of Medicine, MA 02118, USA. marsura@bu.edu A-myb is a member of the myb family of transcription factors, which regulates proliferation, differentiation, and apoptosis of hematopoietic cells. A-Myb expression is normally restricted to the proliferating B-cell centroblasts and transgenic mice overexpressing A-myb displayed enhanced hyperplasia of the lymph nodes. Because A-Myb is highly expressed in several subtypes of human B-cell neoplasias, we sought to determine whether the A-myb gene promoted proliferation and survival of B lymphocytes, using the WEHI 231 and CH33 murine B-cell lymphomas as models. Here, we show that ectopic expression of A-myb rescues WEHI 231 and CH33 cells from growth arrest and apoptosis induced by anti-IgM treatment. Previously, we demonstrated an essential role of the c-myc gene in promoting cell survival of WEHI 231 cells in response to a variety of apoptotic stimuli. Furthermore, we and others have shown that the c-myc gene is potently transactivated by A-Myb in several cell types. Thus, we sought to determine whether c-Myc would mediate the A-Myb antiapoptotic effect in B cells. Here we show that ectopic expression of A-myb leads to maintenance of c-myc expression, and that expression of antisense c-myc RNA ablates A-Myb-mediated survival signals. Thus, these findings strongly implicate the A-myb gene in the regulation of B-cell survival and confirm the c-myc gene as one of the downstream targets of A-myb in these cells. Overall, our observation suggests that A-myb expression may be relevant to the pathology of human B-cell neoplasias. PMID: 10910917 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 75: J Exp Clin Cancer Res. 2000 Mar;19(1):105-11. Molecular analysis of a candidate metastasis-associated gene, MTA1: possible interaction with histone deacetylase 1. Toh Y, Kuninaka S, Endo K, Oshiro T, Ikeda Y, Nakashima H, Baba H, Kohnoe S, Okamura T, Nicolson GL, Sugimachi K. Dept. of Gastroenterologic Surgery, National Kyushu Cancer Center, Fukuoka, Japan. ytoh@nk-cc.go.jp We previously identified a novel rat candidate metastasis-associated gene, mta1, based on its differential expression in highly metastatic cells compared to nonmetastatic cells. Furthermore, we showed that overexpression of its human counterpart, MTA1, correlated with the invasiveness or lymph node metastasis of gastric, colorectal and esophageal carcinomas. The aim of this study was to analyze the domains of the MTA1 and investigate the function(s) of this protein. Structural analysis revealed that the MTA1 protein contained a GATA-like zinc-finger domain, a leucine zipper domain, a SANT domain similar to the DNA binding domain of myb-related proteins, a src homology 3-binding domain important in protein-protein interactions, two highly acidic regions characteristic of the acidic activation domains of many transcription factors, and nuclear localization signals. Immunofluorescence staining of COS-7 cells transfected with a myc-epitope-tagged MTA1 expression vector clearly showed nuclear localization of MTA1. Coimmunoprecipitation of myc-tagged MTA1 and FLAG-tagged histone deacetylase 1 (HDAC1), followed by western blot analysis using anti-myc and anti-FLAG monoclonal antibodies showed that MTA1 physically bound with HDAC1 in COS-7 cells. Together with the recent finding that the NURD (nucleosome remodeling and histone deacetylase activities) complex contains an MTA1-related gene product, named MTA2, MTA1 may be another component of this complex and be involved in the alteration of chromatin structure and transcription repression. PMID: 10840944 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 76: Proc Natl Acad Sci U S A. 2000 Jun 6;97(12):6481-6. CpG methylation as a mechanism for the regulation of E2F activity. Campanero MR, Armstrong MI, Flemington EK. Department of Cancer Immunology and AIDS, Harvard Medical School and Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA, 02115, USA. Regulation of gene expression in mammals through methylation of cytosine residues at CpG dinucleotides is involved in the development and progression of tumors. Because many genes that are involved in the control of cell proliferation are regulated by members of the E2F family of transcription factors and because some E2F DNA-binding sites are methylated in vivo, we have investigated whether CpG methylation can regulate E2F functions. We show here that methylation of E2F elements derived from the dihydrofolate reductase, E2F1, and cdc2 promoters prevents the binding of all E2F family members tested (E2F1 through E2F5). In contrast, methylation of the E2F elements derived from the c-myc and c-myb promoters minimally affects the binding of E2F2, E2F3, E2F4, and E2F5 but significantly inhibits the binding of E2F1. Consistent with these studies, E2F3, but not E2F1, activates transcription through methylated E2F sites derived from the c-myb and c-myc genes whereas both E2F1 and E2F3 fail to transactivate a reporter gene that is under the control of a methylated dihydrofolate reductase E2F site. Together, these data illustrate a means through which E2F activity can be controlled. PMID: 10823896 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 77: 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] --------------------------------------------------------------- 78: J Biochem (Tokyo). 2000 May;127(5):845-54. Molecular cloning and genomic analysis of mouse GalNAc alpha2, 6-sialyltransferase (ST6GalNAc I). Kurosawa N, Takashima S, Kono M, Ikehara Y, Inoue M, Tachida Y, Narimatsu H, Tsuji S. Molecular Glycobiology, Frontier Research Program, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198, Japan. cDNA clones encoding mouse GalNAc alpha2,6-sialyltransferase (ST6GalNAc I) were isolated from a mouse submaxillary gland cDNA library. The deduced amino acid sequence of cDNA clones is 526 amino acids in length and has highly conserved motifs among sialyl transferases, sialyl motifs L, S, and VS. The expressed recombinant enzyme exhibited similar substrate specificity to chicken ST6GalNAc I. The mouse ST6GalNAc I gene was expressed in submaxillary gland, mammary gland, colon, and spleen. The mouse ST6GalNAc I gene was also cloned from a mouse genomic library, which was divided into 9 exons spanning over 8 kilobases of genomic DNA. The genomic structure of the mouse ST6GalNAc I gene was similar to that of the mouse ST6GalNAc II gene. Unlike the ST6GalNAc II gene, however, which has a housekeeping gene-like promoter with GC-rich sequences, the ST6GalNAc I gene has two promoters and they do not contain GC-rich sequences but contain putative binding sites for tumor-associated transcription factors such as c-Myb, c-Myc/Max, and c-Ets. Analysis of the 5'-RACE PCR products suggested that the mouse ST6GalNAc I gene expression is regulated by these two promoters in tissue-specific manners. PMID: 10788794 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 79: Cancer Control. 1998 Mar;5(2):163-170. Antisense Oligodeoxynucleotide Technology: Potential Use for the Treatment of Malignant Brain Tumors. Engelhard HH. Division of Neurological Surgery, Northwestern University Medical School, Chicago, Illinois 60611, USA. BACKGROUND: Antisense oligodeoxynucleotides (ODNs) have been proposed as a new therapy for patients with cancer, including malignant brain tumors. Antisense ODNs are taken up by tumor cells and selectively block gene expression. Use of ODNs for brain tumors is attractive due to their theoretical specificity, relative ease of production and, to date, paucity of reported adverse effects. This article presents current information regarding antisense ODNs and their possible future use for the treatment of brain tumors. METHODS: The available published experimental and clinical information regarding antisense ODN treatment of glioblastoma cells and administration into the central nervous system (CNS) was reviewed. Other clinically relevant information pertaining to the molecular biology of antisense ODNs was also collected and summarized. RESULTS: Targets for antisense ODN therapy in malignant glioma cells have included c-myc, c-myb, c-sis, c-erb B, CD44, p34cdc2, bFGF, PDGF, TGF-beta, IGF-1, PKC-alpha tumor necrosis factor, urokinase, and S100beta protein. Few in vivo studies of ODN treatment of brain tumors have yet been reported. Systemically administered ODNs enter the brain only in extremely small quantities; therefore, microinfusion into the brain has been recommended. CONCLUSIONS: Antisense ODNs have been used successfully to block glioblastoma gene expression in vitro and expression of multiple genes within the CNS of experimental animals. Upcoming clinical trials will address the safety of antisense ODN use against malignant brain tumors. PMID: 10761027 [PubMed - as supplied by publisher] --------------------------------------------------------------- 80: Mol Cell Biol. 2000 Mar;20(6):1970-81. Regulation of the resident chromosomal copy of c-myc by c-Myb is involved in myeloid leukemogenesis. Schmidt M, Nazarov V, Stevens L, Watson R, Wolff L. Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, Maryland, USA. c-myb is a frequent target of retroviral insertional mutagenesis in murine leukemia virus-induced myeloid leukemia. Induction of the leukemogenic phenotype is generally associated with inappropriate expression of this transcriptional regulator. Despite intensive investigations, the target genes of c-myb that are specifically involved in development of these myeloid lineage neoplasms are still unknown. In vitro assays have indicated that c-myc may be a target gene of c-Myb; however, regulation of the resident chromosomal gene has not yet been demonstrated. To address this question further, we analyzed the expression of c-myc in a myeloblastic cell line, M1, expressing a conditionally active c-Myb-estrogen receptor fusion protein (MybER). Activation of MybER both prevented the growth arrest induced by interleukin-6 (IL-6) and rapidly restored c-myc expression in nearly terminal differentiated cells that had been exposed to IL-6 for 3 days. Restoration occurred in the presence of a protein synthesis inhibitor but not after a transcriptional block, indicating that c-myc is a direct, transcriptionally regulated target of c-Myb. c-myc is a major target that transduces Myb's proliferative signal, as shown by the ability of a c-Myc-estrogen receptor fusion protein alone to also reverse growth arrest in this system. To investigate the possibility that this regulatory connection contributes to Myb's oncogenicity, we expressed a dominant negative Myb in the myeloid leukemic cell line RI-4-11. In this cell line, c-myb is activated by insertional mutagenesis and cannot be effectively down regulated by cytokine. Myb's ability to regulate c-myc's expression was also demonstrated in these cells, showing a mechanism through which the proto-oncogene c-myb can exert its oncogenic potential in myeloid lineage hematopoietic cells. PMID: 10688644 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 81: Biochem Biophys Res Commun. 2000 Jan 27;267(3):863-9. Rapid gene repression triggered by interleukin-6 at the onset of monocyte differentiation. Graeber TG, Shuai K. Division of Hematology-Oncology, Department of Medicine, University of California, Los Angeles, California, 90095-1678, USA. To date, the majority of characterized extracellular ligand-induced rapid changes in gene expression involve upregulation. Hence, rapid gene repression is either less common or less well studied. To study rapid gene repression during cytokine-initiated differentiation programs, we used the mRNA subtractive hybridization technique of representational difference analysis to isolate repressed genes. Cultures of the myeloid leukemia cell line M1 were induced to terminally differentiate by treatment with interleukin-6 (IL-6). The repressed genes identified in our subtraction products include the genes encoding the growth factor receptor Flt3/Flk2/STK-1 (CD135) and the costimulatory protein CD24 [heat-stable antigen] and the c-myb oncogene. Following 4 h of IL-6 treatment, mRNA levels of these genes are decreased by 45-65% relative to controls and after 8 h by 65-80%. Lipopolysaccharide also triggers the repression of these genes. Protein synthesis inhibitors do not block the IL-6-stimulated repression of c-myb, or c-myc, mRNA, yet they do block the repression of flt3 and CD24 mRNA, demonstrating the existence of both protein synthesis-independent and -dependent mechanisms of cytokine-triggered rapid gene repression during differentiation. Copyright 2000 Academic Press. PMID: 10673382 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 82: 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] --------------------------------------------------------------- 83: Oncogene. 1999 Dec 9;18(52):7552-8. Protein stabilization: a common consequence of mutations in independently derived v-Myc alleles. Gavine PR, Neil JC, Crouch DH. Biomedical Research Centre, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK. Myc is overexpressed in many cancers as a result of gene rearrangement or amplification, but coding sequence changes which cluster in the N-terminal transactivation domain also appear to play a role in tumour progression. The prototypic v-Myc gene of MC29 virus differs from avian c-Myc by a series of mutations, including a change at a regulatory phosphorylation site within the mutational hotspot (thr-61) which is known to potentiate transformation in vitro. We now show that the mutation at thr-61 stabilizes the v-Myc protein (turnover difference) and that this single mutation is both necessary and sufficient for the phenotype. A major involvement of the proteasome in Myc degradation was confirmed, but surprisingly, a dilysine motif adjacent to thr-61 proved not to be the ubiquitin target. Two other v-Myc genes which carry a mutation at thr-61 (avian MH2) or a large deletion encompassing this domain (feline T17) were found to be stabilized to a similar extent as MC29, showing that stabilization is a common feature of independently derived Myc oncogenes. These results suggest a common selective process in the genesis of these three viral oncoproteins and a mechanistic link with Jun, Fos and Myb oncoproteins which are also stabilized relative to their cellular counterparts. PMID: 10602514 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 84: 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] --------------------------------------------------------------- 85: Mol Cell Biol. 1999 Dec;19(12):8442-50. Distinct cellular factors regulate the c-myb promoter through its E2F element. Campanero MR, Armstrong M, Flemington E. Harvard University and Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Most E2F-driven promoters are transiently activated around the G(1)/S transition. Although the promoter for the c-myb proto-oncogene harbors an E2F element, it is induced early in G(1) following entry into the cell cycle. Furthermore, this promoter remains active throughout subsequent cell cycles. Since E2F sites function as repressor elements during G(1) (due to the association of pRb with E2F factors), we investigated whether the E2F element in the c-myb promoter is regulated differently than E2F elements in promoters that are repressed during G(1). By gel shift analysis, the E2F element from the c-myb promoter was found to form a unique complex, referred to as E2Fmyb-sp, which was not observed with E2F elements from several other promoters. Antibodies to DP-1, E2F1 to -5, p107, or pRb failed to either supershift or block E2Fmyb-sp complex formation. Methylation interference experiments indicate that the DNA contact residues for the E2Fmyb-sp complex are distinct from but overlapping with residues required for the binding of E2F proteins. In addition to the identification of E2Fmyb-sp, we have found that SP-1 binds to the c-myb E2F element. Functional studies revealed that E2Fmyb-sp and/or SP-1 are required to achieve full activation of the c-myb promoter in different cell types and to maintain elevated expression of the c-myb promoter during G(1) in NIH 3T3 cells. These studies demonstrate that E2F elements can be regulated differently through the binding of unique sets of proteins. PMID: 10567569 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 86: Antisense Nucleic Acid Drug Dev. 1999 Oct;9(5):487-92. Antisense strategies to inhibit restenosis. Lee M, Simon AD, Stein CA, Rabbani LE. Columbia University College of Physicians & Surgeons, Department of Medicine, New York, NY 10032, USA. Restenosis after percutaneous transluminal coronary angioplasty (PTCA) and coronary stenting remains a major clinical problem. Vascular smooth muscle cell (SMC) proliferation and migration from the arterial wall media into the intima are believed to play a critical role in the pathogenesis of restenosis. Several studies have demonstrated that phosphorothioate (PS) oligodeoxynucleotides targeted against genes involved in SMC proliferation inhibit in vitro SMC proliferation and migration. Moreover, PS oligodeoxynucleotides targeted against the genes c-myb, c-myc, cdc2 kinase, cdk2 kinase, and proliferating cell nuclear antigen (PCNA) when delivered adventitially or intraluminally inhibit in vivo neointimal formation after balloon injury in both the rat carotid and porcine coronary artery models. The inhibitory effects of these PS oligodeoxynucleotides may be the result of their suppression of migration of medial SMC rather than suppression of medial or intimal cell proliferation. Other studies have demonstrated the presence of the potent guanosine or G-quartet aptameric inhibitory effect of the PS oligodeoxynucleotides. Experiments with cytidine homopolymers such as S-dC28, which lack guanosines, reveal the presence of potent non-G-quartet, non-sequence-specific inhibitory effects on in vitro SMC proliferation, migration, and adhesion as well as in vivo neointimal formation after rat carotid artery balloon injury. This is owing to the avid binding of these PS oligodeoxynucleotides to the SMC mitogens and chemoattractants platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF). The extent to which hybridization-dependent antisense, G-quartet aptameric, or non-G-quartet, non-sequence-specific inhibitory effects occurs is the result of PS oligodeoxynucleotide sequence, length, and concentration. The 18-mer guanosine-rich PS oligodeoxynucleotide ZK10 is a more potent in vitro SMC proliferation inhibitor than S-dC28, although both compounds manifest comparable in vivo inhibitory effects on neointimal formation in the rat carotid artery model of balloon injury. PS oligodeoxynucleotides also possess non-sequence-specific immunomodulatory effects, including the induction of interferon-gamma and the unmethylated CpG motif, which exhibits numerous immunomodulatory effects. Novel strategies to inhibit restenosis include the development of E2F transcription decoys that inhibit several cell cycle regulatory genes and diminish neointimal lesion formation. In addition, antisense oligonucleotides targeted against the anti-apoptotic gene bcl-xL, which when transfected into the vessel wall inhibits bcl-xl expression, induce a five-fold increase in apoptotic SMC intimal cells, and effect a marked attenuation of in vivo lesion dimensions, thereby suggesting frank vascular lesion regression. Publication Types: Review Review, Tutorial PMID: 10555157 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 87: Mol Gen Genet. 1999 Aug;262(1):65-72. A light-inducible Myb-like gene that is specifically expressed in red Perilla frutescens and presumably acts as a determining factor of the anthocyanin forma. Gong ZZ, Yamazaki M, Saito K. Faculty of Pharmaceutical Sciences, Research Center of Medicinal Resources, Chiba University, Japan. The Myb-p1 gene was isolated by screening for differentially expressed Myb-related genes in red (anthocyanin-producing) and green (anthocyanin nonproducing) forms of Perilla frutescens. Expression of Myb-p1 is increased 10-fold in the red relative to the green form of P. futescens, and the gene is induced by light. MYB-P1 has only one DNA-binding region, which corresponds to repeat III in the general structure of MYB proteins. In the yeast two-hybrid system, it was shown that MYB-P1 interacted with MYC-RP, a MYC-related transcriptional regulatory protein involved in the control of anthocyanin biosynthesis in P. frutescens. In yeast, MYB-P1 was able to bind to a dihydroflavonol reductase (DFR) gene promoter isolated from red P. frutescens. These data suggest that Myb-p1 may be involved in the regulation of anthocyanin biosynthesis and could therefore be responsible for determining anthocyanin formation in red P. frutescens. PMID: 10503537 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 88: Anticancer Drug Des. 1999 Jun;14(3):179-86. Effect of ecteinascidin-743 on the interaction between DNA binding proteins and DNA. Bonfanti M, La Valle E, Fernandez Sousa Faro JM, Faircloth G, Caretti G, Mantovani R, D'Incalci M. Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. Ecteinascidin-743 (ET-743) is a tetrahydroisoquinoline alkaloid isolated from Ecteinascidia turbinata, a tunicate growing in mangrove roots in Caribbean. It has been shown to bind in the minor groove of DNA forming covalent adducts by reaction of the N2 of guanine with the carbinolamine moiety. We investigated ET-743 ability to inhibit the binding of different transcription factors to their consensus sequences by using gel shift assays. We have selected three types of factors: (i) oncogene products such as MYC, c-MYB and Maf; (ii) transcriptional activators regulated during the cell cycle as E2F and SRF; and (iii) general transcription factors such as TATA binding protein (TBP), Sp1 and NF-Y. We observed no inhibition of the binding of Sp1, Maf, MYB and MYC. Inhibition of DNA binding was observed for TBP, E2F, SRF at ET-743 concentrations ranging from 50 to 300 microM. The inhibition of binding of NF-Y occurs at even lower concentrations (i.e. 10-30 microM) when the recombinant subunits of NF-Y are preincubated with the drug, indicating that the inhibition of NF-Y binding does not require previous ET-743 DNA binding. Since NF-Y is a trimer containing two subunits with high resemblance to histones H2B and H2A, we have investigated the effect of ET-743 on nucleosome reconstitution. ET-743 caused a decrease of the nucleosomal band at 100 nM, with the complete disappearance of the band at 3-10 microM. These data suggest that the mode of action of this novel anticancer drug is related to its ability to modify the interaction between some DNA binding proteins and DNA. PMID: 10500494 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 89: Gene Ther. 1999 Jun;6(6):1184-91. Tissue-selective expression of dominant-negative proteins for the regulation of vascular smooth muscle cell proliferation. Schmitt JF, Keogh MC, Dennehy U, Chen D, Lupu F, Weston K, Taylor D, Kakkar VV, Lemoine NR. Thrombosis Research Institute, London, UK. The transcription factors c-myb and c-myc are essential for vascular smooth muscle cell (VSMC) replication and are rapidly induced following mitogenic stimulation of quiescent VSMCs in vitro and in vivo following balloon catheter injury. Consequently, interference with c-myb and c-myc function provides a possible avenue for the prevention of VSMC proliferation associated with intimal hyperplasia. We have carried out studies focused on the inhibition of VSMC proliferation using dominant-negative gene constructs incorporating the DNA-binding domains of the c-myb or c-myc genes fused to the repressor domain of the Drosophila engrailed gene. Transient transfection of rat, rabbit and human vascular SMCs results in a dramatic inhibition of proliferation for at least 72 h after transfection. Furthermore, this inhibition of cellular proliferation was found to be due, at least in part, to the induction of apoptosis. Coupling expression of the chimeric dominant-negative proteins to transcriptional regulatory elements of the human vascular smooth muscle alpha-actin gene allows specific targeting of vascular smooth muscle cells. PMID: 10455424 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 90: Cancer Res. 1999 Jul 15;59(14):3365-8. Expression of B-myb in neuroblastoma tumors is a poor prognostic factor independent from MYCN amplification. Raschella G, Cesi V, Amendola R, Negroni A, Tanno B, Altavista P, Tonini GP, De Bernardi B, Calabretta B. ENEA CR Casaccia, Section of Toxicology and Biomedical Sciences, Rome, Italy. The transcription factors of the Myb family are expressed in several tissues and play an important role in cell proliferation, differentiation, and survival In this study, the expression of A-myb, B-myb, and c-myb was investigated in a group of 64 neuroblastomas at different dinical stages by a sensitive reverse transcription-PCR tchnique and correlated with patients' survival. All of the myb genes were frequently expressed in neuroblastoma tumors. Interestingly, the expression of B-myb, which was detected in 33 cases, was associated with an increased risk of death (P = 0.027 in a univariate analysis), whereas there was no correlation with A-myb and c-myb expression. In addition, in a multivariate Cox regression analysis that included myb gene expression, MYCN status, age at diagnosis, and tumor staging, MYCN amplification and B-myb expression were independently associated to an increased risk (P < 0.01 and P = 0.015, respectively). In overall survival curves obtained by stratifying the neuroblastoma cases on the basis of MYCN status and B-myb expression, the group of patients without MYCN amplification and positive for B-myb expression had worse survival probability than that without MYCN amplification and nonexpressing B-myb (P < 0.01). In summary, these findings provide the first demonstration that B-myb expression can be a useful prognostic marker in human neuroblastoma. Moreover, B-myb expression has a prognostic value complementary to MYCN amplification and can identify a group of high-risk patients that would not be predicted on the basis of the MYCN status only. PMID: 10416595 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 91: Cytokines Cell Mol Ther. 1999 Mar;5(1):15-23. Antisense strategy in hematological malignancies. Warzocha K. Department of Hematology, Medical University of Lodz, Poland. Standard cytotoxic chemotherapy for neoplastic disease is fraught with systemic toxicity. The ratio of the toxic dose to the therapeutic dose is relatively low, which reflects the large number of cellular targets affected by the chemotherapeutic agent as well as its inability to distinguish between normal and malignant cells. The discovery of oncogenes and tumor suppressor genes involved in the process of transformation of normal cells into malignant cells has opened new areas of research in oncology, aimed at discovering drugs that could selectively inhibit their biological effects. This therapeutic modality, called an antisense strategy, has become a powerful tool for selectively reducing the expression of target genes in vitro, and there is increasing interest in the possibility of using the same technology in vivo for therapeutic purposes. In oncohematology, a number of trials have been initiated with antisense oligonucleotides directed against molecular targets, including the bcl-2, c-myc, bcr-abl, c-myb or p53 oncogenes and tumor suppressor genes. The experience gained from these studies will be applicable to the next generation of antisense compounds, which may include oligonucleotides with novel backbones or other structural modifications, as well as for expansion of the use of antisense oligonucleotides in combination approaches for the treatment of hematological malignancies. Publication Types: Review Review, Tutorial PMID: 10390076 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 92: Oncogene. 1999 Jun 17;18(24):3643-7. Cooperation of Myb and Myc proteins in T cell lymphomagenesis. Davies J, Badiani P, Weston K. CRC Centre for Cell and Molecular Biology, Institute of Cancer Research, London, UK. The v-Myb oncogene causes late onset T cell lymphomas when expressed in the T cell lineage of transgenic mice. In order to define the cellular mutations cooperating with s-Myb to cause lymphomas, we have infected v-Myb transgenic mice with Moloney murine leukemia virus (M-MuLV). Tumor formation is significantly accelerated from a mean age of onset of 60 weeks in uninfected vMyb transgenics to 13 weeks in infected vMyb transgenics. We studied the loci into which the M-MuLV had inserted, and found that in 73% of animals, either the c-myc or the N-myc genes had been disrupted and deregulated. Therefore, v-myb and c-myb can cooperate to induce T cell lymphomas. PMID: 10380886 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 93: Oncogene. 1999 May 13;18(19):3034-8. Reassessing the role of C-MYB in tumorigenesis. Weston K. CRC Centre for Cell and Molecular Biology, Institute of Cancer Research, London, UK. Hematopoietic tumors in both humans and mice frequently up-regulate expression of the c-myb gene, but it is unclear whether this is a cause or a consequence of the leukemic state. Recent results placing super-activation of the c-Myb protein at the bottom of a kinase-activated signal transduction pathway indicate that it may be a downstream effector of transformation induced by other oncogenes. The relationship between c-Myb and the serine-threonine kinase pim-1, its immediate activator, is discussed, together with the possibility that c-Myb, like pim-1, may be able to synergize with c-Myc to induce tumors. Publication Types: Review Review, Tutorial PMID: 10378698 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 94: Oncogene. 1999 May 13;18(19):2914-5. Myc and Myb: are the veils beginning to lift? Prendergast GC. The Wistar Institute, Philadelphia, Pennsylvania 19104, USA. PMID: 10378687 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 95: Mamm Genome. 1999 Jun;10(6):556-9. The fit-1 common integration locus in human and mouse is closely linked to MYB. Barr NI, Stewart M, Tsatsanis C, Fulton R, Hu M, Tsujimoto H, Neil JC. Molecular Oncology Laboratory, Department of Veterinary Pathology, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK. The fit-1 locus was originally identified as a common insertion site for feline leukemia virus (FeLV) in thymic lymphosarcomas induced by FeLV-myc recombinant viruses, suggesting that it harbors a gene that cooperates with Myc in T-cell leukemogenesis. We have previously mapped the fit-1 locus to feline Chromosome (Chr) B2. We have now identified conserved sequences that allow the mapping of the murine homolog using the European Interspecific Backcross (EUCIB). This shows that fit-1 is located on mouse Chr 10, 1cM proximal to Ahi-1, a murine retroviral integration locus that is closely linked to Myb. Moreover, the physical linkage to MYB is maintained in the human genome, as shown by cloning of the human homolog of fit-1 from a Chr 6 cosmid library and a series of overlapping PAC clones. Generation of a contig map around the human homolog of fit-1 reveals that it is approximately 100-kb upstream of MYB. In addition to fit-1 and Ahi-1, two other common insertion sites, Mis-2 and Mml-1, have also been mapped adjacent to Myb on mouse Chr 10. Previous analysis of tumors carrying insertions at fit-1, Mml-1, Mis-2 and Ahi-1 showed no obvious abnormalities in Myb expression. However, the cluster of viral insertion loci in this region suggests either the presence of a closely linked activation target or that subtle effects on Myb have been overlooked. PMID: 10341084 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 96: Oncogene. 1999 Apr 15;18(15):2489-98. Differential effects of the widely expressed dMax splice variant of Max on E-box vs initiator element-mediated regulation by c-Myc. FitzGerald MJ, Arsura M, Bellas RE, Yang W, Wu M, Chin L, Mann KK, DePinho RA, Sonenshein GE. Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA. dMax, a naturally occurring splice variant of the Myc binding protein Max, lacks the DNA binding basic region and helix 1 of the Helix-Loop-Helix domain; dMax interacts with c-Myc in vitro and in vivo, and inhibits E-box Myc site driven transcription in transient transfection assays. Here we have investigated the expression, function and interactions of dMax. RT/PCR analyses detected dmax mRNA in multiple tissues of the developing, newborn and adult mouse. Functionally, dMax reduced the ability of c-Myc to cooperate with the progression factor A-Myb to promote S phase entry of quiescent smooth muscle cells. In contrast, dMax failed to ablate inhibition of initiator element (Inr)-mediated transcription by c-Myc in Jurkat T cells. In in vitro protein:protein association assays, dMax interacted with c-Myc, N-Myc, L-Myc, Mad1, Mxi1, Mad3 and Mad4, but not with itself or wild-type Max. These interactions required an intact leucine zipper. Inhibition of E-box-mediated transactivation by induction of dMax overexpression resulted in apoptosis of WEHI 231 B cells. Thus, dMax is a widely expressed, naturally occurring protein, with the capacity to bind most members of the Myc/Max superfamily; dMax has little effect on Inr-mediated repression by c-Myc, but can significantly decrease E-box-mediated events promoting proliferation and cell survival. PMID: 10229200 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 97: 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] --------------------------------------------------------------- 98: AIDS Res Hum Retroviruses. 1999 Mar 1;15(4):375-9. Identification of TAXREB107 as an erythropoietin early response gene. Li R, Madden H, Sytkowski AJ. Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA. The protooncogenes c-myc and c-myb are erythropoietin (Epo)-regulated early response genes. They appear to play distinct roles in the growth- and differentiation-inducing signals of the hormone. Using a subtractive hybridization strategy, we have identified the murine homolog of the TAX response element-binding protein TAXREB107 as an Epo early response gene in Rauscher murine erythroleukemia cells. This was confirmed by Northern blot analyses, which showed a fourfold increase in TAXREB107 mRNA after 1 hr of erythropoietin treatment. After 3 hr the transcript had decreased to approximately twofold above control levels. Inhibition of this induction with antisense oligodeoxynucleotides increased Epo-induced hemoglobinization 2.5-fold. The results implicate TAXREB107 in erythropoiesis and support the hypothesis that the TAXREB proteins have functions outside the context of HTLV-I infection. PMID: 10082121 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 99: Gene. 1998 Dec 28;225(1-2):47-57. Expression cloning in Fe2+ transport defective yeast of a novel maize MYC transcription factor. Loulergue C, Lebrun M, Briat JF. Biochimie et Physiologie Moleculaire des Plantes. Centre National de la Recherche Scientifique (URA 2133), Universite Montpellier II, Institut National de la Recherche Agronomique et Ecole Nationale Superieure d'Agronomie, Place Viala, F-34060,France. A complementation approach of the yeast fet3fet4 mutant strain, defective in both low- and high-affinity iron transport, was initiated as an attempt to characterize the Fe(III)-mugineic acid (MA) transporter from grasses. A maize cDNA encoding a novel MYC transcription factor, named 7E, was cloned by screening an iron-deficient maize root cDNA expression library on a minimum media containing Fe(III)-deoxyMA as a unique iron source. 7E expression restored growth specifically to the fet3 fet4 mutant strain. It did not affect growth rate of a trk1trk2 potassium transport defective yeast strain or parental W303 strain growth rate. No 55Fe uptake increase was observed in 7E transformed fet3 fet4 yeast during short-term kinetics. However, the iron accumulation in these cells was 1.3-fold higher than in untransformed cells after a 24-h period. The 7E protein contained 694 amino acids and had a predicted molecular mass of 74.2kDa. It had 44% identity with the RAP-1 protein, a 67.9-kDa MYC-like protein from Arabidopsis thaliana which binds the G-box sequence via a basic region helix-loop-helix (bHLH), without requiring heterodimerization with MYB proteins. Phylogenic comparisons revealed that the maize 7E protein was related to the Arabidopsis thaliana RAP-1 protein and to the Phaseolus vulgaris PG1. This similarity was particularly evident for the bHLH domain, which was 95% identical between maize 7E and Arabidopsis thaliana RAP-1. 7E, RAP-1 and PG-1 proteins revealed a plant MYC-like sub-family that was more related to the maize repressor-like IN1 than to maize R proteins. 7E mRNA was detected in both roots and leaves by the Northern analysis. The amount of 7E mRNA increased, in response to iron starvation, by 20 and 40% in roots and leaves, respectively. The relationship between iron metabolism and myc expression in animal cells is discussed. PMID: 9931428 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 100: Mol Cell. 1998 Oct;2(4):417-25. Pim-1 kinase and p100 cooperate to enhance c-Myb activity. Leverson JD, Koskinen PJ, Orrico FC, Rainio EM, Jalkanen KJ, Dash AB, Eisenman RN, Ness SA. Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500, USA. The pim-1 oncogene is regulated by hematopoietic cytokine receptors, encodes a serine/threonine protein kinase, and cooperates with c-myc in lymphoid cell transformation. Using a yeast two-hybrid screen, we found that Pim-1 protein binds to p100, a transcriptional coactivator that interacts with the c-Myb transcription factor. Pim-1 phosphorylated p100 in vitro, formed a stable complex with p100 in animal cells, and functioned downstream of Ras to stimulate c-Myb transcriptional activity in a p100-dependent manner. Thus, Pim-1 and p100 appear to be components of a novel signal transduction pathway affecting c-Myb activity, linking all three to the cytokine-regulated control of hematopoietic cell growth, differentiation, and apoptosis. PMID: 9809063 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 101: Oncogene. 1998 Sep 10;17(10):1189-94. Normal development, oncogenesis and programmed cell death. Liebermann DA. Fels Institute for Cancer Research and Molecular Biology, Philadelphia, Pennsylvania 19140, USA. Meeting's Report -- June 2, 1998, Sugarload Estate Conference Center, Philadelphia, Pennsylvania, USA. A symposium on Normal Development, Oncogenesis and Programmed Cell Death, was held at the Sugarload Estate Conference Center, Philadelphia, Pennsylvania, USA sponsored by the Fels Cancer Institute, Temple University School of Medicine, with the support of the Alliance Pharmaceutical Corporation. The symposium was organized by Drs Dan A Liebermann and Barbara Hoffman at the Fels. Invited speakers included: Dr Andrei V Gudkov (University of Illinois) who started the symposium talking about 'New cellular factors modulating the tumor suppressor function of p53'; Dr Yuri Lazebnik (Cold Spring Harbor Laboratories) spoke about 'Caspases considered as enemies within'; Dr E Premkumar Reddy (Fels Institute, Temple University) talked about recent exciting findings in his laboratory regarding 'JAK-STATs dedicated signaling pathways'; Dr Michael Greenberg (Harvard University) spoke about 'Signal transduction pathways that regulate differentiation and survival in the developing nervous system'; Dr Richard Kolesnick's (Memorial Sloan-Kettering Cancer Center) talk has been focused at 'Stress signals for apoptosis, including Ceramide and c-Jun Kinase/Stress-activated Protein Kinase'; Dr Barbara Hoffman (Fels Institute, Temple University) described research, conducted in collaboration with Dr Dan A Liebermann, aimed at deciphering the roles of 'myc, myb, and E2F as negative regulators of terminal differentiation', using hematopoietic cells as model system. Dr Daniel G Tenen (Harvard Medical School), described studies aimed at understanding the 'Regulation of hematopoietic cell development by lineage specific transcription regulators'. Dr George C Prendergast (The Wistar Institute) talked about the 'Myc-Bin1 signaling pathway in cell death and differentiation. Dr Ruth J Muschel (University of Pennsylvania) spoke about work, conducted in collaboration with Dr WG McKenna, aimed at gaining a better understanding of 'Radioresistance and the cell cycle'. Finally Dr Donald Kufe concluded the symposium (Dana Farber Cancer Institute, Harvard Medical School) describing studies that were performed in his laboratory addressing the 'Role for the c-Abl tyrosine kinase in genetic recombination'. Publication Types: Congresses PMID: 9771961 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 102: Endocrinology. 1998 Oct;139(10):4164-74. Estrogen receptor expression and function in long-term estrogen-deprived human breast cancer cells. Jeng MH, Shupnik MA, Bender TP, Westin EH, Bandyopadhyay D, Kumar R, Masamura S, Santen RJ. Department of Internal Medicine, University of Virginia Health Sciences Center, Charlottesville 22908, USA. mj5x@virginia.edu Hormone-dependent breast cancer responds to primary therapies that block estrogen production or action, but tumor regrowth often occurs 12-18 months later. Additional hormonal treatments that further reduce estrogen synthesis or more effectively block its action cause additional remissions, but the mechanisms responsible for these secondary responses are not well understood. As a working hypothesis, we postulated that primary hormonal therapy induces adaptive changes, resulting in enhanced estrogen receptor (ER) expression and target gene activation and, further, that secondary treatment modalities interfere with these receptor-mediated transcriptional pathways. To test this hypothesis, we used an MCF-7 breast cancer model system involving deprivation of estradiol in culture for a prolonged period. These long-term estradiol-deprived (LTED) cells adapt by acquiring the ability to regrow in the absence of added estradiol. The experimental paradigm involved the comparison of wild-type cells with LTED cells. As endpoints, we directly assessed ER expression at the messenger RNA-, protein-, and ligand-binding levels and ER functionality by quantitating reporter gene activation and expression of endogenous estrogen target gene messenger RNA, as well as ER coactivator levels. Our data demonstrated an adaptive increase in ER expression and in basal ER functionality, as assessed by read-out of three different transfected reporters in LTED, as opposed to wild-type MCF-7 cells. Increased reporter gene read-out was dramatically inhibited by the pure antiestrogen ICI 182,780. As verification that endogenous (as well as transfected) estrogen target genes had enhanced transcription, we found that the basal levels of c-myb and c-myc message were substantially increased in LTED cells and could be inhibited by antiestrogen. Interestingly, the levels of c-myb and c-myc message in the LTED cells seemed to be increased out of proportion to the degree of ER reporter gene activation and were similar to those in wild-type cells maximally stimulated with estradiol. In addition, not all estrogen-responsive genes were activated, because transforming growth factor-alpha message level was not increased in LTED cells. Up-regulation of the steroid receptor coactivator SRC-1 did not seem to mediate the process of enhanced ER-induced transcription. Considering these observations together, we suggest that long-term estradiol deprivation causes adaptive processes that not only involve up-regulation of the ER but also influence the specificity and magnitude of activation of estrogen-responsive genes. PMID: 9751496 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 103: Blood. 1998 Sep 15;92(6):1957-66. The zinc finger transcription factor Egr-1 activates macrophage differentiation in M1 myeloblastic leukemia cells. Krishnaraju K, Hoffman B, Liebermann DA. Fels Institute for Cancer Research and Molecular Biology, and Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, USA. We previously have shown that the zinc finger transcription factor Egr-1 blocked granulocytic differentiation of HL-60 cells, restricting differentiation along the monocytic lineage. Egr-1 also was observed to block granulocyte colony-stimulating factor (G-CSF)-induced differentiation of interleukin-3 (IL-3)-dependent 32Dcl3 hematopoietic precursor cells, endowing the cells with the ability to be induced by granulocyte-macrophage colony-stimulating factor (GM-CSF) for terminal differentiation along the macrophage lineage. To better understand the function of Egr-1 as a positive modulator of monocytic differentiation, in this work we have studied the effect of ectopic expression of Egr-1 on the murine myeloblastic leukemic cell line M1, which is induced for differentiation by the physiological inducer IL-6. It is shown that, unlike in HL-60 and 32Dcl3 cells, ectopic expression of Egr-1 in M1 cells resulted in activation of the macrophage differentiation program in the absence of differentiation inducer. This included the appearance of morphologically differentiated cells, decreased growth rate in mass culture, and cloning efficiency in soft agar, and expression of endogenous c-myb and c-myc mRNAs was markedly downregulated. Untreated M1Egr-1 cells also exhibited cell adherence, expression of Fc and C3 receptors, and upregulation of the myeloid differentiation primary response genes c-Jun, junD, and junB and the late genetic markers ferritin light-chain and lysozyme. Ectopic expression of Egr-1 in M1 cells also dramatically increased the sensitivity of the cells for IL-6-induced differentiation, allowed a higher proportion of M1 cells to become terminally differentiated under conditions of optimal stimulation for differentiation, and decreased M1 leukemogenicity in vivo. These findings demonstrate that the functions of Egr-1 as a positive modulator of macrophage differentiation vary, depending on the state of lineage commitment for differentiation of the hematopoietic cell type. Copyright 1998 by The American Society of Hematology. PMID: 9731053 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 104: Indian J Exp Biol. 1998 May;36(5):447-55. Oncogene expression as detected by immunocytochemical staining in hormonally induced ovarian cell lines. Luthra K, Chapekar TN. Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India. To understand the nature and extent of oncogene involvement in the development of neoplasia, an experimental model of goat ovarian granulosa cells stimulated by LH was chosen. In the course of these studies, several cell lines were developed which were essentially non-tumorigenic primary cell lines. One of them, however, was spontaneously transformed being immortalized and tumorigenic. These cell lines, transformed and non-transformed, should serve as contralateral cell lines to study differential oncogene expression in hormonally induced cell proliferation, and elucidate possible hormone-oncogene nexus which may be operative in the genesis of cancer. In the present report, we have studied expression of c-myc, c-ras, c-myb, c-fos and c-sis cellular oncogenes in the cell lines by immunocytochemistry using monoclonal antibodies. In the rest of our text we refer to these cellular oncogenes as oncogenes. The results reveal differential expression of the oncogenes. The striking difference between the non-transformed AIMS/GRXII cells and the transformed AIMS/GRXVIII cells was the absence of ras protein expression in the transformed AIMS/GRXVIII cells which intensely expressed the c-myc, c-myb, c-fos, and c-sis proteins. c-ras protein was expressed in the non-transformed AIMS/GRXVIII cell line and primary cultures. c-myc protein was expressed exclusively in the AIMS/GRXVIII transformed cells. The myc activity seen in the transformed cell line may be correlated to cell proliferation. These results show the variation of phenotype in cell lines derived from a single tissue source. PMID: 9717461 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 105: Leuk Lymphoma. 1998 Jul;30(3-4):293-306. Changes in oncogene expression implicated in evolution of chronic granulocytic leukemia from its chronic phase to acceleration. Beck Z, Bacsi A, Kovacs E, Kiss J, Kiss A, Balogh E, Telek B, Toth FD, Andirko I, Olah E, Udvardy M, Rak K. Institute of Microbiology, University Medical School, Debrecen, Hungary. Expression of nine oncogenes was investigated in cell samples from fifteen patients with Philadelphia chromosome (Ph)-positive chronic granulocytic leukemia (CGL) both at diagnosis and at the onset of accelerated phase (AP) of the disease. The bcr-abl fusion gene, the H-ras gene and the c-myb gene were universally expressed. In comparison with the chronic phase (CP) of the disease, an increase in the levels of bcr-abl-, c-myb- and H-ras-related transcripts was found in three, two and three AP samples, respectively. Elevation of the bcr-abl-related message was associated with duplication of the Ph chromosome and amplification of the bcr-abl fusion gene in one AP sample. No CP samples were positive for c-myc or c-sis expression. On the contrary, c-myc and c-sis were expressed in three and four AP samples, respectively. The presence of c-myc-related transcript was associated with trisomy 8 with or without amplification of the c-myc oncogene in leukemia cells of two patients with CGL in AP. No changes of oncogene expression were found in four AP samples. However, we observed deletions of chromosome 13 and 17 or i(17q) in three of them, suggesting that tumor suppressor gene alterations may also be responsible for the development of AP of CGL. Our data indicate that heterogeneous alterations in oncogenes and tumor suppressor genes accompany the evolution of CGL-CP to the AP of the disease. PMID: 9713961 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 106: J Biol Chem. 1998 Aug 14;273(33):21423-9. Myb-dependent regulation of thrombospondin 2 expression. Role of mRNA stability. Bein K, Ware JA, Simons M. Angiogenesis Research Center, Cardiovascular Division, Department of Medicine Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA. The nuclear transcription factor c-Myb, which is highly expressed in hematopoietic cells, has been shown to be functional in NIH 3T3 cells: cells that do not possess detectable levels of c-Myb. To identify endogenous target genes of c-Myb in fibroblasts, RNA isolated from NIH 3T3 cells stably transfected with a full-length or a dominant negative c-myb construct (GREMyb and GREMEn, respectively) was subjected to differential display analysis. 5'-Rapid amplification of cDNA ends of a selected band, sequencing, and a nucleotide homology search led to the identification of thrombospondin 2 (TSP 2) as the gene product repressed in GREMyb and induced in GREMEn cells. The pattern of TSP 2 expression during the cell cycle was consistent with c-myb-dependent regulation. The possibility that the identified transcript was TSP 1, a homologous product known to be repressed by v-Src, c-Jun, and v-Myc, was ruled out by using a TSP 2-specific DNA probe and by showing a distinct pattern of regulation of TSP 1 and TSP 2 expression. Nuclear run-on and TSP 2 promoter-reporter (chloramphenicol acetyltransferase) assays showed similar transcriptional levels in GREMyb and NIH 3T3 cells. However, mRNA stability studies showed a much shorter TSP 2 mRNA half-life in GREMyb compared with wild type NIH 3T3 cells, suggesting that c-myb affects TSP 2 expression via a post-transcriptional mechanism. The implications of a protooncogene-mediated suppression of TSP expression are discussed. PMID: 9694906 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 107: Am J Physiol. 1998 Aug;275(2 Pt 2):F278-84. An oligonucleotide decoy for transcription factor E2F inhibits mesangial cell proliferation in vitro. Tomita N, Horiuchi M, Tomita S, Gibbons GH, Kim JY, Baran D, Dzau VJ. Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. The transcription factor E2F controls expression of several genes involved in cell proliferation including c-myc, c-myb, proliferating cell nuclear antigen (PCNA), and cdk2 kinase. Having established that both PCNA and cdk2 kinase are induced in rat mesangial cells (MC) by serum stimulation, we attempted to inhibit MC proliferation in vitro by transfecting these cells with cationic liposomes containing a synthetic double-stranded oligodeoxynucleotide (ODN) with high affinity for E2F. Using a gel mobility shift assay, we detected increased specific binding of E2F in MC following serum stimulation. This binding was completely inhibited by preincubation of MC nuclear extracts with the double-stranded ODN with high affinity for E2F but not by preincubation with a missense ODN containing two point mutations. MC were also transfected with a luciferase reporter gene construct containing three E2F binding sites. Luciferase activity was enhanced by serum stimulation of MC, and this effect was specifically abolished by cotransfection of MC with E2F decoy ODN. Furthermore, RT-PCR analysis revealed that serum-induced upregulation of PCNA and cdk2 kinase gene expression was inhibited by E2F decoy ODN transfection but not by transfection of missense ODN. These changes in gene expression were paralleled by a reduction in PCNA and cdk2 kinase protein expression in E2F decoy ODN transfected cells. MC number increased following serum stimulation. This effect was blunted by transfection with E2F decoy ODN but not by transfection of missense ODN. These data suggest that the transcription factor E2F plays a crucial role in the regulation of MC proliferation and that this factor can be successfully targeted to inhibit MC cell cycle progression. PMID: 9691019 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 108: J Mol Biol. 1998 Jul 31;280(5):785-98. Regulation of c-fos expression by RNA polymerase elongation competence. Pinaud S, Mirkovitch J. Swiss Institute for Experimental Cancer Research (ISREC), Chemin des Boveresses 155, Epalinges, CH-1066, Switzerland. The molecular mechanisms underlying transcription elongation and their role in gene regulation are poorly characterized in eukaryotes. A number of genes, however, have been proposed to be regulated at the level of transcription elongation, including c-myc, c-fos and c-myb. Here, we analyze the control of transcription elongation at the mouse c-fos gene at the nucleotide level in intact cells. We find that RNA polymerases are engaged in the promoter-proximal part of the gene in the absence of gene activation signals and mRNA synthesis. Importantly, we determine that the engaged RNA polymerases originate from a continuous initiation of transcription which, in the absence of gene activation signals, terminate close to the promoter. We also observe that the c-fos gene presents an active chromatin conformation, with the promoter and upstream regulatory sequences constitutively occupied by proteins, accounting for the continuous initiation of RNA polymerase complexes. We propose that activation of c-fos gene expression results primarily from the assembly of elongation-competent RNA polymerases that can transcribe the complete gene. Our results suggest that the engaged RNA polymerases found downstream of a number of other eukaryotic promoters may be associated with transcription termination of elongation-incompetent polymerases in the absence of activating signals. Copyright 1998 Academic Press. PMID: 9671550 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 109: 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] --------------------------------------------------------------- 110: Ital J Gastroenterol Hepatol. 1997 Apr;29(2):148-54. Intrahepatic expression of c-fos, c-myb and c-myc oncogenes: correlation with virus-induced chronic liver disease and response to interferon. Tappero G, Farina M, Negro F, Anfossi G, Mattiello L, Giuli PD, Colombatto P, Brunetto MR, Angeli A, Bonino F. Department of Internal Medicine, University of Turin, S. Luigi Hospital, Orbassano, Italy. BACKGROUND & AIMS: Oncogenes were activated in experimental models of hepatocyte regeneration. We studied the intrahepatic expression of c-fos, c-myb and c-myc protooncogenes in 117 patients with chronic liver disease: 12 with hepatitis B, 15 HBsAg carriers, 73 with hepatitis C and 17 with non-viral liver damage. METHODS: Oncoproteins were detected by indirect immunofluorescence using high affinity and monoclonal antibodies. Grade and stage of liver damage were measured by numerical score. RESULTS: Nuclear c-fos and/or c-myb were found in 7 (58.3%) hepatitis B patients, in 38 (52%) hepatitis C patients, in 1 (6.6%) HBsAg carrier (p < 0.004) and in none of the non-viral disease patients (p < 0.0001). In no case was c-myc detected. Oncoproteins were correlated with the histological activity index (p < 0.0001) and its components: lobular degeneration and periportal necrosis (p < 0.0001), fibrosis (p < 0.005) and portal inflammation (p < 0.03). Thirty-one chronic hepatitis C patients were treated with alpha-IFN: 9 out of 14 oncoprotein-positive patients (64%) were non-responders, 5 (36%) relapsed and none was a sustained responder. Conversely 9 out of 17 (53%) oncoprotein-negative patients, including 3 patients with histologically active cirrhosis, showed long-term response (p < 0.005). CONCLUSIONS: Intrahepatic c-fos and c-myb were detected in chronic viral hepatitis patients, but not in non-viral liver diseases. Their expression correlated with the grade and stage of liver disease and with poor response to alpha-IFN. PMID: 9646196 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 111: J Immunol. 1998 Jun 15;160(12):5898-906. Erratum in: J Immunol 1999 Jul 15;163(2):1093. CpG oligodeoxyribonucleotides rescue mature spleen B cells from spontaneous apoptosis and promote cell cycle entry. Yi AK, Chang M, Peckham DW, Krieg AM, Ashman RF. Medical Services, Department of Veterans Affairs, Iowa City, IA 52246, USA. Isolated murine splenic B cells undergo spontaneous apoptosis. Motifs containing unmethylated CpG dinucleotides in bacterial DNA or in synthetic oligodeoxynucleotides (ODN) are known to activate murine B cells. Now we show that ODN that induce spleen B cell cycle entry also inhibit spontaneous apoptosis in a sequence-specific fashion. Reversal of the CG to GC abolished activity. Methylation of the central cytosine decreased activity. When CpG is preceded by a cytosine or followed by a guanine, activity was abolished. Other substitutions at the same positions had no effect. Dose-response curves for apoptosis protection and G1 entry suggested that a uniform population of ODN recognition sites controlled downstream ODN effects. A CpG ODN with a nuclease-resistant phosphorothioate backbone (S-ODN) was also active, and increased the levels of c-myc, egr-1, c-jun, bclXL, and bax mRNA and c-Myc, c-Jun, Bax, and BclXL protein in spleen B cells. Levels of c-myb, myn, c-Ki-ras, and bcl2 mRNA remained unchanged. When protein synthesis was inhibited, at 16 h ODN-induced cell cycle entry was abolished and apoptosis protection was partially preserved. Under these conditions, c-Myc was still present, but c-Jun and BclXL were not detected. Our results suggest that CpG containing ODN motifs provide signals for both survival and cell cycle entry. Single base changes determine whether this signal proceeds through a rate-limiting step governing at least two steps in apoptosis (plasma membrane transition, DNA cleavage) and two phases of the cell cycle (G1 and S phase entry). This biologic action is associated with increased c-Myc, c-Jun, and BclXL expression. PMID: 9637502 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 112: Blood. 1998 Jun 1;91(11):4136-44. NF-kappaB transcription factors are involved in normal erythropoiesis. Zhang MY, Sun SC, Bell L, Miller BA. Department of Pediatrics, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033-0850, USA. NF-kappaB/Rel designates a widely distributed family of transcription factors involved in immune and acute phase responses. Here, the expression and function of NF-kappaB factors in erythroid proliferation and differentiation were explored. In an erythroleukemia cell line, TF-1, high levels of p105/p50, p100/p52, p65, and IkappaBalpha were detected 24 hours after growth factor deprivation. In response to granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation, significant induction of p52 expression was observed. GM-CSF also induced nuclear translocation of both p52 and p65. No induction of NF-kappaB factors was observed with erythropoietin stimulation of TF-1 cells. Overexpression of p52 and p65 in TF-1 cells by transient transfection resulted in significant induction of a kappaB-TATA-luciferase reporter plasmid, showing that these factors are functional in vivo in erythroid cells. To determine whether NF-kappaB factors may play a role in normal erythropoiesis, levels of these factors were determined in burst-forming unit-erythroid (BFU-E)-derived cells at different stages of differentiation. The NF-kappaB factors p105/p50, p100/p52, and p65 were highly expressed in early BFU-E-derived precursors, which are rapidly proliferating, and declined during maturation. Furthermore, nuclear levels of NF-kappaB factors p50, p52, and p65 were higher in less mature precursors (day 10 BFU-E-derived cells) compared with more differentiated (day 14) erythroblasts. In nuclear extracts from day 10 BFU-E-derived cells, p50, p52, and p65 were able to form complexes, which bound to kappaB sites in the promoters of both the c-myb and c-myc genes, suggesting that c-myb and c-myc may be among the kappaB-containing genes regulated by NF-kappaB factors in normal erythroid cells. Taken together, these data show that NF-kappaB factors are modulated by GM-CSF and suggest they function to regulate specific kappaB containing genes involved in erythropoiesis. PMID: 9596659 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 113: Leuk Res. 1998 Feb;22(2):135-43. Proto-oncogene expression in bovine peripheral blood leukemic lymphocytes during their spontaneous proliferation, differentiation and apoptosis in vitro. Kalvelyte AV, Pabrezaite LC. Institute of Biochemistry, Vilnius, Lithuania. kazimk@ktl.mii.lt The expression of various proto-oncogenes in primary culture of lymphocytes from peripheral blood of bovine with chronic lymphocytic leukemia (CLL) was studied. Cellular proto-oncogenes encode proteins that propagate growth, differentiation or apoptosis signals from cell membrane to nucleus. The proliferation and differentiation of normal eukaryotic cells are precisely controlled. Tumor cells usually are characterized both by the continuous growth signal and by the block of cell differentiation. We have previously reported that along with spontaneous proliferation, bovine CLL lymphocytes continuously differentiate and enter apoptosis in vitro. CLL cells with an autocrine growth mechanism and at the same time undergoing spontaneous differentiation and apoptosis in vitro provide a new model system to investigate the possible involvement of various proto-oncogenes in the regulation of cellular proliferation, differentiation and apoptosis. Northern blot analysis revealed simultaneous expression of a number of proto-oncogenes in CLL cells. Transcripts of c-fos, c-myc, c-myb, A-raf, c-raf1, hck, IL-2 receptor alpha-chain (IL-2R alpha) were found in lymphocytes at the peak of their proliferative activity in culture. Kinetics studies demonstrated that CLL cells constitutively express transcripts of so-called immediate response nuclear proto-oncogenes c-myc, c-fos as well as cytoplasmic proto-oncogenes hck and c-raf1, i.e., genes coding for tyrosine and serine-threonine protein kinases, respectively. Expression level did not change significantly during all stages of CLL cells in culture. The results show that continuous expression of c-myc mRNA does not prevent CLL cell differentiation and may be associated with apoptotic cell death. PMID: 9593470 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 114: Gene. 1998 Apr 14;210(2):287-95. The gene structure and promoter analysis of mouse lymphocyte signal transduction molecule alpha 4 that is related to the yeast TAP42 involved in a rapamycin-sensitive pathway. Maeda K, Inui S, Sanjo H, Sakaguchi N. Department of Immunology, Kumamoto University School of Medicine, Japan. The mouse alpha 4 phosphoprotein encoding a component associated with the B cell antigen receptor (BCR)-mediated signal transduction is suggested to be involved in a unique rapamycin-sensitive pathway. We studied the structure and the molecular mechanism of the expression of alpha 4 gene by isolating two phage clones, named #10 and #23, covering entire exons of the mouse alpha 4 gene. The alpha 4 gene is located within about 25 kb and composed of six exons. To analyze the regulation of alpha 4 gene expression, we determined the nucleotide sequence toward 2 kb upstream of the translation start site of the alpha 4 gene. The 5'-flanking region does not contain a typical TATA box or the initiation consensus sequence, but it contains a CCAAT box, E-boxes, and several DNA binding motifs such as c-Myc, c-Myb, and c-Ets. Transcription of the alpha 4 gene starts at four different sites, determined by primer extension analysis, that were surrounded by Y-rich sequences. We further characterized the functional promoter of the alpha 4 gene at the region between -263 and the transcription start site of alpha 4 gene by luciferase assay system and suggested that the 5' upstream region of alpha 4 gene contains the silencer element of MT repetitive sequence. PMID: 9573385 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 115: Dev Biol. 1998 Mar 1;195(1):16-28. Defective development of the embryonic liver in N-myc-deficient mice. Giroux S, Charron J. Centre de recherche en cancerologie de l'Universite Laval, Quebec, Canada. The mechanisms involved in the formation and the differentiation of the liver remain unclear despite extensive studies. To investigate these events in mouse hepatic development, we have taken advantage of the N-myc mutant mouse line which exhibits abnormal liver development. N-myc mutant embryos die between 11.5 and 12.5 days postcoitum most probably from heart failure. In the present study, we report that at 11.5 days of gestation, extensive apoptosis restricted to the hepatocytes occurred in N-myc mutant liver when compared to wild-type samples. Moreover, the number of hematopoietic cells is reduced in the mutant liver. During early liver organogenesis, the N-myc gene is expressed in tissues involved in the induction and the differentiation of the hepatocytes. At 11.5 days postcoitum, both c-myc and N-myc genes are expressed in the liver. While c-myc is expressed at a high level in the organ per se, N-myc expression is mostly confined to the peripheral layer of the liver which will generate the Glisson's capsule. Taken together, the expression pattern of N-myc in the liver and the specific apoptosis of hepatocytes observed in N-myc mutants indicate that N-myc is required for hepatocyte survival and suggest that it is involved in the genetic cascade leading to normal liver development. PMID: 9520320 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 116: Int Rev Immunol. 1998;16(3-4):249-84. Interleukin 6 and its receptor: ten years later. Hirano T. Department of Molecular Oncology, Osaka University Medical School, Japan. hirano@molonc.med.osaka-u.ac.jp Ten years have passed since the molecular cloning of interleukin 6 (IL-6) in 1986. IL-6 is a typical cytokine, exhibiting functional pleiotropy and redundancy. IL-6 is involved in the immune response, inflammation, and hematopoiesis. The IL-6 receptor consists of an IL-6 binding alpha chain and a signal transducer, gp130, which is shared among the receptors for the IL-6 related cytokine subfamily. The sharing of a receptor subunit is a general feature of cytokine receptors and provides the molecular basis for the functional redundancy of cytokines. JAK tyrosine kinase is a key molecule that can initiate multiple signal-transduction pathways by inducing the tyrosine-phosphorylation of the cytokine receptor, gp130 in the case of IL-6, on which several signaling molecules are recruited, including STAT, a signal transducer and activator of transcription, and SHP-2, which links to the Ras-MAP kinase pathway. JAK can also directly activate signaling molecules such as STAT and Tec. These multiple signal-transduction pathways intimately regulate the expression of several genes including c-myc, c-myb, junB, IRF1, egr-1, and bcl-2, leading to the induction of cell growth, differentiation, and survival. The deregulated expression of IL-6 and its receptor is involved in a variety of diseases. Publication Types: Review Review, Tutorial PMID: 9505191 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 117: Mol Gen Genet. 1998 Jan;257(2):198-204. Anthocyanin regulatory mutations in pea: effects on gene expression and complementation by R-like genes of maize. Uimari A, Strommer J. Department of Molecular Biology and Genetics, University of Guelph, Ontario, Canada. Anthocyanin production in higher plants is a function of the tissue considered and its developmental stage, and is modulated by environmental factors. In maize, the best characterized system, regulation of the pathway is achieved largely through the action of proteins with homology to the transcriptional factors encoded by myc and myb proto-oncogenes of animals; these homologues control the expression of structural genes and thus regulate the availability of anthocyanin biosynthetic enzymes. We have studied anthocyanin biosynthesis and its regulation in flowers of pea (Pisum sativum). Our results demonstrate a correlation between anthocyanin accumulation and steady-state mRNA levels for genes encoding chalcone synthase, flavanone 3 beta-hydroxylase, and dihydroflavonol 4-reductase in developing flowers. Patterns of expression for these biosynthetic genes in both a and a2 mutants confirm the regulatory roles of the two a loci. The reduced expression of all three biosynthetic genes in mutant lines suggests that genes acting both early and late in the anthocyanin biosynthetic pathway are controlled by a and a2. Particle bombardment of floral tissue demonstrates the ability of two maize R-like genes, Lc and R-S, but neither myb-like genes nor R-like genes from snapdragon or petunia, functionally to complement a and a2 mutations. We cannot distinguish whether a and a2 act coordinately or sequentially in anthocyanin regulation, but the epistatic action of maize R-like genes suggests that they mimic the action of a gene that normally functions downstream of both a and a2 in the regulatory cascade. PMID: 9491078 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 118: 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] --------------------------------------------------------------- 119: Cell Signal. 1997 Nov;9(7):483-95. Signalling mechanisms in erythropoiesis: the enigmatic role of calcium. Schaefer A, Magocsi M, Marquardt H. Department of Toxicology, Hamburg University Medical School, FRG. The glycoprotein hormone, erythropoietin is the principal regulator of the production of circulating erythrocytes by controlling proliferation, differentiation and survival of its target erythroid progenitor cells. The receptor for erythropoietin is a type I cytokine receptor lacking intrinsic tyrosine kinase activity. It mediates tyrosine phosphorylation through its association with nonreceptor tyrosine kinases such as JAK2 and initiates a cascade of signalling events in response to erythropoietin. Significant progress has been made in identifying signalling pathways triggered by erythropoietin. However, the exact signalling mechanisms mediating the known physiological effects of erythropoietin in erythroid progenitor cells are poorly understood. There are many open questions including the role of Ca2+ in erythropoietin induced signal transduction. Although the results concerning the effect of erythropoietin on [Ca2+]i in various erythroid cells are conflicting, [Ca2+]i-increasing agents mimic the effect of erythropoietin on c-myb expression and activate the program of haemoglobin synthesis in murine erythroleukemia cells. An attempt is made in this review to survey recent data on the erythropoietin-induced signal transduction with respect to the different physiological effects of this hormone. Publication Types: Review PMID: 9419812 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 120: Oncogene. 1997 Dec 11;15(24):2885-98. Inactivation of a c-Myb/estrogen receptor fusion protein in transformed primary cells leads to granulocyte/macrophage differentiation and down regulation of c-kit but not c-myc or cdc2. Hogg A, Schirm S, Nakagoshi H, Bartley P, Ishii S, Bishop JM, Gonda TJ. Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, South Australia. Primary murine fetal hemopoietic cells were transformed with a fusion protein consisting of the ligand-binding domain of the estrogen receptor and a carboxyl-terminally truncated c-Myb protein (ERMYB). The ERMYB-transformed hemopoietic cells exhibit an immature myeloid phenotype when grown in the presence of beta-estradiol. Upon removal of beta-estradiol, the ERMYB cells display increased adherence, decreased clonogenicity and differentiate to cells exhibiting granulocyte or macrophage morphology. The expression of the c-myc, c-kit, cdc2 and bcl-2 genes, which are putatively regulated by Myb, was investigated in ERMYB cells grown in the presence or absence of beta-estradiol. Neither c-myc nor cdc2 expression was down-regulated after removal of beta-estradiol demonstrating that differentiation is not a consequence of decreased transactivation of these genes by ERMYB. While bcl-2 expression was reduced by 50% in ERMYB cells grown in the absence of beta-estradiol, there was no increase in DNA laddering, suggesting that Myb was not protecting ERMYB cells from apoptosis. In contrast, a substantial (200-fold) decrease in c-kit mRNA level was observed following differentiation of ERMYB cells, and c-kit mRNA could be partially re-induced by the re-addition of beta-estradiol. Furthermore, a reporter construct containing the c-kit promoter was activated when cotransfected with a Myb expression vector, providing further evidence of a role for Myb in the regulation of c-kit. PMID: 9416832 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 121: Br J Haematol. 1997 Dec;99(3):500-8. Constitutive and inducible expression of megakaryocyte-specific genes in Friend erythroleukaemia cells. Vannucchi AM, Linari S, Cellai C, Koury MJ, Paoletti F. Division of Haematology, Careggi Hospital, Florence, Italy. Friend murine erythroleukaemia cells (MELC) were analysed by semiquantitative RT-PCR for the constitutive and inducible expression of megakaryocyte-specific genes. Uninduced MELC expressed detectable levels of mRNAs for acethylcholinesterase (AChE), platelet factor-4 (PF4), glycoprotein IIb (GPIIb) and von Willebrand factor (VWF), whereas the erythroid alpha- and beta-globin genes were not transcribed appreciably. However, MELC exposed to 5 mM hexamethylene bisacetamide (HMBA) or 1.5% dimethyl sulphoxide (DMSO) seemed to be channelled towards a mixed erythroid/megakaryocytic phenotype characterized by unaltered levels of VWF mRNA, increased levels of AChE, GPIIb and PF4 mRNA. and simultaneous induction of the globin genes. Megakaryocyte-related genes were expressed. in the absence of globin gene transcription, by MELC treated with either phorbol-12-myristate acetate (PMA; 100 ng/ml) or colcemid (40 nM), an antimicrotubule agent capable of promoting polyploidization in this model. Moreover, PMA and colcemid induced also de novo expression of the thrombopoietin receptor c-mpl. PMA and colcemid did not affect high basal c-myb mRNA levels which, in turn, were down-regulated upon HMBA or DMSO induction. Additionally, both uninduced and induced MELC exhibited significant levels of Epo-R and IL-3R mRNAs, whereas no expression of granulocyte/macrophage-related genes was detected. Megakaryocyte gene expression of MELC was also compared to that of other haemopoietic cell populations from normal mice and mice infected with the anaemic strain of the Friend virus. According to our results, MELC should be seen as an unique erythro-megakaryocytic model of differentiation, potentially useful for studying molecular events governing lineage commitment as well as some steps of megakaryocytopoiesis. PMID: 9401056 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 122: Rinsho Byori. 1997 Nov;45(11):1048-56. [Molecular pathomechanism of HTLV-I infectious diseases] [Article in Japanese] Kitajima I. Department of Laboratory Medicine, Kagoshima University of School of Medicine. Human T-cell lymphotropic virus type I(HTLV-I) is a type C retrovirus, closely associated with adult T-cell leukemia. In the past few years, studies have revealed an association between the virus and disorders of organ systems including myelopathy, polymyositis, alveolitis, and Sjogren's syndrome. In addition, we have proposed that HTLV-I-associated proliferative changes in nonlymphocyte synovial cells are termed HTLV-I-associated arthropathy(HAAP). To clarify the pathologic association of HTLV-I with this arthropathy, we attempted to detect HTLV-I proviral DNA in synovial tissue. Proviral HTLV-I DNA was detected not only in peripheral blood mononuclear cells but also in fresh synovial tissue cells and lymphocyte-depleted cultured synovial cells. We also detected mRNA for HTLV-I tax/rex in cultured synovial cells by reverse transcription polymerase chain reaction. Moreover, induction of chronic inflammatory arthropathy in mice transgenic for HTLV-I tax gene strongly suggested the pathogenic mechanism of HAAP. Histologic findings of affected joints in mice showed erosions of bones and pannus-like granulomtous change with infiltration of mononuclear cells. Thus, this novel mechanism might explain synovial proliferation caused by HTLV-I. Tax-expressing transgenic mouse lines also demonstrated that tax itself could serve as an oncogne in fibroblastic cells. Tumors occurred in 100% of the mice with reproducible time periods after wounding. We established cell lines, which expressed high levels of c-fos, c-myc, myb, PDGF, TGF-beta, Zif, and IL-6. Antisense ablation of the p65 subunits of NF-kappa B profoundly inhibited tumor growth in vitro with no apparent affect on the growth of normal cells. These studies were successfully extended to tax-transgenic animals. Intraperitoneal injections of NF-kappa B p65 antisense at the 40 micrograms/g weight dose led to growth arrest after 7 days, and apparent involution after 20 days of treatment. We think activation of NF-kappa B by Tax is important for tumor progression. This paper supports the importance of analyzing molecular pathomechanisms. Publication Types: Review Review, Tutorial PMID: 9396344 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 123: Plant Cell. 1997 Oct;9(10):1859-68. Role of arabidopsis MYC and MYB homologs in drought- and abscisic acid-regulated gene expression. Abe H, Yamaguchi-Shinozaki K, Urao T, Iwasaki T, Hosokawa D, Shinozaki K. Biological Resources Division, Japan International Research Center for Agricultural Sciences (JIRCAS), Ibaraki, Japan. In Arabidopsis, the induction of a dehydration-responsive gene, rd22, is mediated by abscisic acid (ABA) and requires protein biosynthesis for ABA-dependent gene expression. Previous experiments established that a 67-bp DNA fragment of the rd22 promoter is sufficient for dehydration- and ABA-induced gene expression and that this DNA fragment contains two closely located putative recognition sites for the basic helix-loop-helix protein MYC and one putative recognition site for MYB. We have carefully analyzed the 67-bp region of the rd22 promoter in transgenic tobacco plants and found that both the first MYC site and the MYB recognition site function as cis-acting elements in the dehydration-induced expression of the rd22 gene. A cDNA encoding a MYC-related DNA binding protein was isolated by DNA-ligand binding screening, using the 67-bp region as a probe, and designated rd22BP1. The rd22BP1 cDNA encodes a 68-kD protein that has a typical DNA binding domain of a basic region helix-loop-helix leucine zipper motif in MYC-related transcription factors. The rd22BP1 protein binds specifically to the first MYC recognition site in the 67-bp fragment. RNA gel blot analysis revealed that transcription of the rd22BP1 gene is induced by dehydration stress and ABA treatment, and its induction precedes that of rd22. We have reported a drought- and ABA-inducible gene that encodes the MYB-related protein ATMYB2. In a transient transactivation experiment using Arabidopsis leaf protoplasts, we demonstrated that both the rd22BP1 and ATMYB2 proteins activate transcription of the rd22 promoter fused to the beta-glucuronidase reporter gene. These results indicate that both the rd22BP1 (MYC) and ATMYB2 (MYB) proteins function as transcriptional activators in the dehydration- and ABA-inducible expression of the rd22 gene. PMID: 9368419 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 124: Ann Vasc Surg. 1997 Nov;11(6):581-7. Inhibition of intimal hyperplasia by an antisense oligonucleotide of farnesyl transferase delivered endoluminally during iliac angioplasty in a rabbit model. Chemla E, Castier Y, Julia P, Pirotski E, Carpentier A, Fabiani JN. Service de Chirurgie Thoracique et Cardiovasculaire, Hopital Broussais, Paris, France. The major complication of vascular recanalization is intimal hyperplasia which is due mainly to proliferation and migration of smooth muscle cells (SMC). Activation of SMC results from stimulation of protooncogens (c-myb, c-myc, c-fos) by growth factors induced by activated ras-proteins. Ras-proteins become activated after receiving a farnesyl group in a reaction catalyzed by famesyl transferase. The purpose of this study was to test the effectiveness in preventing intimal hyperplasia of an antisense oligonucleotide of the alpha subunit of farnesyl-transferase delivered endoluminally during angioplasty of the common iliac artery in rabbit model. Twenty-one male New Zealand rabbits with a mean weight of 3.3 kg fed a high cholesterol diet underwent bilateral angioplasty of the common iliac artery using hydrogel-coated balloon catheters. On the right side three types of treatment were randomly performed by adding one of the following three oligonucleotides to the hydrogel precoating:antisense oligonucleotide of farnesyl transferase (n = 7), mismatch oligonucleotide (n = 7), and scramble oligonucleotide (n = 7). On the left side hydrogel was used with saline so that each animal served as its own control. Animals were killed 6 weeks after angioplasty and arteries were studied. The thickness and mean surface of the neointima (MTI and MSI) and the ratio (R) of the neointima to neointima + media were calculated. In the scramble and mismatch groups there was no difference between the treated and control arteries with regard to MTI, MSI, or R. In the antisense group mean all three values were significantly lower on the treated side than the control side (EMI: p < 0.02, SMI: p < 0.02, and R: p < 0.01). Treated arteries in the antisense group presented significantly lower EMI (p < 0.02), SMI (p < 0.02), and R (p < 0.01) than treated arteries in the other groups whereas the thickness and mean surface of the media were comparable. Endoluminal administration of an antisense oligonucleotide against the alpha subunit of farneysyl transferase inhibited intimal hyperplasia in our model. PMID: 9363303 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 125: Mol Cells. 1997 Aug 31;7(4):537-43. Characterization of the murine cyclin D2 gene: exon/intron organization and promoter activity. Jun DY, Kim MK, Kim IG, Kim YH. Department of Microbiology, College of Natural Sciences, Kyungpook National University, Taegu, Korea. Cyclin D2 is normally expressed in G1 and promotes progression through G1 of the cell cycle. From a murine genomic library constructed with spleen DNA, two overlapping genomic clones of cyclin D2 were isolated. These clones contain most of the exon of cyclin D2 except exon 5. Characterization of these clones revealed that murine cyclin D2 mRNA spans over 18 kb and 5 exons ranging from 149 to approximately 462 bp in length, and suggested that exon 5 may be at least >5 kb downstream from exon 4. Primer extension analysis of cyclin D2 mRNA isolated from murine activated T cells detected 5 putative sites of transcription initiation. These are located at - 499, - 417, - 391, - 373, and - 349 relative to the translation start site, which is given as + 1. No consensus sequence for TATA box existed at an appropriate position within the promotor region. Instead, several putative transcriptional factor binding sites for C/EBP, PEA3, AP2, NF-Y, Sp1, c-Myc, GATA-1, AP1, v-Myb, and CREB were detected. The 5'-flanking region of the cyclin D2 gene up to nucleotide - 945 shared about 61% sequence homology between mouse and human. Functional analysis of promoter activity of the 5'-flanking region of cyclin D2 suggested that the region - 1,100 to - 805 including C/EBP, PEA3, AP2, NF-Y, c-Myc, and Sp1 may have a major positive regulatory activity for expression of cyclin D2. PMID: 9339900 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 126: Biochem Biophys Res Commun. 1997 Sep 29;238(3):764-8. Association of Stat3-dependent transcriptional activation of p19INK4D with IL-6-induced growth arrest. Narimatsu M, Nakajima K, Ichiba M, Hirano T. Department of Oncology, Biomedical Research Center, Osaka University Medical School, Suita, Japan. Signal transducer and activator of transcription 3 (Stat3) is the major mediator of the IL-6-induced signals regulating growth and differentiation. In the M1 myeloleukemic cell line, Stat3 is a critical transcription factor causing repression of c-myc and c-myb genes, expression of junB and IRF1, growth arrest at G1, and subsequent macrophage differentiation. To understand the mechanisms by which Stat3 causes such effects, we searched for other Stat3-regulated genes possibly involved in growth arrest. We identified this inducible molecule as p19INK4D using a specific antibody. Both p19INK4D mRNA and protein were rapidly induced by IL-6 treatment without requiring de novo protein synthesis and the induction was fully suppressed by dominant-negative forms of Stat3. Thus both Stat3-regulated events, repressions of c-myc and c-myb and induction of p19INK4D, are likely to be involved in IL-6-induced growth arrest in M1 cells. PMID: 9325164 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 127: Leuk Lymphoma. 1997 Jul;26(3-4):271-9. The A-myb transcription factor in neoplastic and normal B cells. Golay J, Facchinetti V, Ying G, Introna M. Department of Immunology and Cellular Biology, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy. The myb family of transcription factors has been strongly implicated in the regulation of cell growth and differentiation in the haematopoietic system. The v-myb oncogene, carried by avian defective retroviruses, causes leukaemias in the chicken and transforms haematopoietic cells in vitro. Its normal cellular equivalent c-myb, has been shown to promote the proliferation and block the differentiation of haematopoietic cells in several experimental models and is required for fetal haematopoiesis. Two other members of the family have been cloned more recently, A-myb and B-myb, which show sequence homology with c-myb in several domains, of which the DNA binding domain as well as other regulatory domains. Both have been shown to be transcription factors. B-myb is also involved in the control of proliferation and differentiation, but, unlike c-myb, it is expressed in many cell types. The third member of the family, A-myb, shows the most restricted pattern of expression, suggesting a very specific role for this transcription factor. A-myb is expressed in a subpopulation of normal B lymphocytes activated in vivo and localised in the germinal center of peripheral lymphoid organs and is not detected at significant levels in all other mature or immature haematopoietic populations studied, including bone marrow cells, T lymphocytes, granulocytes, monocytes, either at rest or after in vitro activation. These studies indicate that A-myb plays a role during a narrow window of normal B cell differentiation. A-myb expression has also been studied in a wide range of neoplastic B cells, representing the whole spectrum of B cell differentiation. A-myb is strongly expressed in Burkitt's lymphomas (BL) and slg+ B-acute lymphoblastic leukaemias (B-ALL) and not in all other leukaemias/lymphomas tested, with the exception of a subset of CLL (about 25% of cases). It is intriguing that the A-myb genome has been localised relatively close to the c-myc gene on chromosome 8, suggesting that the c-myc translocation in BL and B-ALL may affect A-myb transcription. Studies are in progress to investigate the functional relationship between A-myb and c-myc, particularly in the context of BL cells and to determine whether A-myb is deregulated in these cells. Publication Types: Review Review, Tutorial PMID: 9322889 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 128: J Biol Chem. 1997 Oct 3;272(40):24921-6. The DNA binding domain of the A-MYB transcription factor is responsible for its B cell-specific activity and binds to a B cell 110-kDa nuclear protein. Ying GG, Arsura M, Introna M, Golay J. Laboratory of Molecular Immunohematology, Department of Immunology and Cell Biology, Istituto Ricerche Farmacologiche "Mario Negri," via Eritrea 62, 20157 Milano, Italy. Expression studies as well as the use of transgenic animals have demonstrated that the A-MYB transcription factor plays central and specific role in the regulation of mature B cell proliferation and/or differentiation. Furthermore, it is highly expressed in Burkitt's lymphoma cells and may participate in the pathogenesis of this disease. We have therefore investigated the transcriptional activity of A-MYB and its regulation in several human lymphoid cell lines using co-transfection assays and show that A-MYB is transcriptionally active in all the B cell lines studied, but not in T cells. In particular the best responder cell line was the Burkitt's cell line Namalwa. The activity of A-MYB in B and not T cells was observed when either an artificial construct or the c-MYC promoter was used as a reporter. Furthermore, the functional domains responsible for DNA binding, transactivation, and negative regulation, previously characterized in a fibroblast context, were found to have similar activity in B cells. The region of A-MYB responsible for the B cell specific activity was defined to be the N-terminal 218 amino acids containing the DNA binding domain. Finally, a 110-kDa protein has been identified in the nuclei of all the B, but not T, cell lines that specifically binds to this A-MYB N-terminal domain. We hypothesize that this 110-kDa protein may be a functionally important B cell-specific co-activator of A-MYB. PMID: 9312094 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 129: 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] --------------------------------------------------------------- 130: Int J Cancer. 1997 Aug 7;72(4):687-95. Leukemia inhibitory factor induces apoptosis and proliferation of human carcinoma cells through different oncogene pathways. Kamohara H, Sakamoto K, Ishiko T, Masuda Y, Abe T, Ogawa M. Department of Surgery II, Kumamoto University School of Medicine, Japan. Leukemia inhibitory factor (LIF) affects the growth of carcinoma cells, and we thus analyzed its underlying mechanisms. Carcinoma cells constitutively express LIF mRNA, and 23 lines (92.0%) and all (100%) of 25 lines express LIF receptor mRNAs of LIFRbeta and gp130, respectively. Exogenous addition of LIF promoted significant cell proliferation in 4 lines (MCF-7, ZR-75-1, Hs-700T and Panc-1) and suppressed cell growth in 3 lines (AZ-521, GBK-1 and HT-29). LIF significantly induced an immediate early response of genes c-fos and junB 3 hr after stimulation, but not of c-jun during the process of proliferation of MCF-7 and Hs-700T cells, with maximum levels at 30-60 min. The cell-cycle-related gene cyclin E was also induced in MCF-7 and Hs-700T cells, whereas cyclinA, cdk2, c-myc, c-myb and p53 mRNAs were not induced. On the other hand, LIF inhibited growth and increased the rate of cell death of AZ-521 and GBK-1 cells. LIF increased the number of TUNEL-positive cells in AZ-521 cells and DNA fragmentation in AZ-521 and GBK-1 cells. LIF induced apoptosis related genes c-myc and ICE during suppression of cell growth, but p53, p21, c-fos, cyclin A and cyclin E were not induced. Our results suggest that LIF is linked to cell proliferation and apoptosis in some human carcinoma cell lines. It is considered that this is related to differences in signal transduction and induction of oncogenes. PMID: 9259411 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 131: Mol Cell Biochem. 1997 Jul;172(1-2):199-211. DNA antisense strategies in the study of receptors for vasoactive peptides, and of growth and wound-healing factors. D'Orleans-Juste P, Sirois MG, Edelman ER, Regoli D, Pheng LH, Bkaily G, Lindsey CJ. Department of Pharmacology, Faculty of Medicine, Universite de Sherbrooke, Quebec, Canada. Antisense oligodeoxynucleotide technology has contributed greatly to the overall understanding of both mRNA stability as well as translational processes leading to protein synthesis. Arrest of translational processes by DNA antisense strands usually reduces maximal effects of agonists without affecting their apparent affinities in treated isolated vascular or nonvascular preparations. In the present study, examples are given of DNA antisense oligonucleotide-induced repression of receptors for endothelins, kinins as well as of the platelet-derived growth factor. Furthermore, the efficiency of this technology illustrates the roles of protooncogenes (c-myc and c-myb) in wound-healing mechanisms. The overall mechanism of action of these oligomers is described and the relevance of size, chemical alterations and mode of delivery are illustrated. Release of oligophosphorothioates from polymer matrices and gels can produce a prolonged effect in vivo. Antisense oligonucleotides remain essential in experimental models for which receptor antagonists or selective inhibitors of intracellular components are currently unavailable. Publication Types: Review Review, Tutorial PMID: 9278246 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 132: Mol Cell Biol. 1997 May;17(5):2448-57. A-myb is expressed in bovine vascular smooth muscle cells during the late G1-to-S phase transition and cooperates with c-myc to mediate progression to S phase. Marhamati DJ, Bellas RE, Arsura M, Kypreos KE, Sonenshein GE. Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA. The Myb family of transcription factors is defined by homology within the DNA binding domain and includes c-Myb, A-Myb, and B-Myb. The protein products of the myb genes all bind the Myb-binding site (MBS) [YG(A/G)C(A/C/G)GTT(G/A)]. A-myb has been found to display a limited pattern of expression. Here we report that bovine aortic smooth muscle cells (SMCs) express A-myb. Sequence analysis of isolated bovine A-myb cDNA clones spanning the entire coding region indicated extensive homology with the human gene, including the putative transactivation domain. Expression of A-myb was cell cycle dependent; levels of A-myb RNA increased in the late G1-to-S phase transition following serum stimulation of serum-deprived quiescent SMC cultures and peaked in S phase. Nuclear run-on analysis revealed that an increased rate of transcription can account for most of the increase in A-myb RNA levels. Treatment of SMC cultures with 5,6-dichlorobenzimidazole riboside, a selective inhibitor of RNA polymerase II, indicated an approximate 4-h half-life for A-myb mRNA during the S phase of the cell cycle. Expression of A-myb by SMCs was stimulated by basic fibroblast growth factor, in a cell density-dependent fashion. Cotransfection of a human A-myb expression vector activated a multimerized MBS element-driven reporter construct approximately 30-fold in SMCs. The activity of c-myb and c-myc promoters, which both contain multiple MBS elements, were similarly transactivated, approximately 30- and 50-fold, respectively, upon cotransfection with human A-myb. Lastly, A-myb RNA levels could be increased by a combination of phorbol ester plus insulin-like growth factor 1. To test the role of myb family members in progression through the cell cycle, we comicroinjected c-myc and myb expression vectors into serum-deprived quiescent SMCs. The combination of c-myc and either A-myb or c-myb but not B-myb synergistically led to entry into S phase, whereas microinjection of any vector alone had little effect on S phase entry. Thus, these results suggest that A-myb is a potent transactivator in bovine SMCs and that its expression induces progression into S phase of the cell cycle. PMID: 9111313 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 133: J Immunol. 1997 Apr 15;158(8):3987-95. Characterization of the new immunosuppressive drug undecylprodigiosin in human lymphocytes: retinoblastoma protein, cyclin-dependent kinase-2, and cyclin-dependent kinase-4 as molecular targets. Songia S, Mortellaro A, Taverna S, Fornasiero C, Scheiber EA, Erba E, Colotta F, Mantovani A, Isetta AM, Golay J. Department of Immunology and Cell Biology, Institute of Pharmacological Research Mario Negri, Milan, Italy. Undecylprodigiosin (UP) is the first described member of a family of related compounds showing immunosuppressive activity. We have investigated the biological effect and mechanism of action of UP in human lymphocytes. We show that UP blocks the proliferation of purified peripheral human T and B lymphocytes with an IC50 of 3 to 8 ng/ml and following stimulation by all mitogens used, with no effect on cell death. At the concentrations active on fresh lymphocytes, UP has no significant effect on the proliferation of different leukemic cell lines. UP blocks T cell activation in mid to late G1 phase and before entry into S phase, as shown by analysis of the cell cycle and of the expression of c-myc, IL-2, transferrin receptor, and B-myb. UP inhibits only partially the expression of IL-2R, suggesting that the major target of UP is localized downstream from the interaction between IL-2 and its receptor. The expression of cell cycle genes was investigated. The phosphorylation of the retinoblastoma protein was completely blocked by UP, an event alone sufficient to explain the block of S phase entry and the inhibition of proliferation. The induction of cyclin D2 and the decrease in p27 were not inhibited by UP, whereas the induction of cyclin E, cyclin A, cyclin-dependent kinase-2, and cyclin-dependent kinase-4 was strongly inhibited, potentially explaining the inhibition of retinoblastoma protein phosphorylation. These data clearly show that the site of action of UP is different from that of both cyclosporin A and rapamycin, and that this new class of compounds may, therefore, be good candidates for combined therapy. PMID: 9103470 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 134: Nucleic Acids Res. 1997 Apr 1;25(7):1327-32. Temperature and salt dependence of higher order structure formation by antisense c-myc and c-myb phosphorothioate oligodeoxyribonucleotides containing tetraguanylate tracts. Basu S, Wickstrom E. Department of Microbiology and Immunology and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA. The use of complementary RNA or DNA sequences to selectively interfere with the utilization of mRNA of a target gene is an attractive therapeutic strategy. Two well-studied targets for oligonucleotide therapy are the c-mycand c-mybproto-oncogenes. It has been reported that sequences which contain four contiguous Gs can elicit a non-antisense response, due to the formation of a homotetrameric G quartet structure. Therefore, it was of interest to determine whether anti-c-mycand anti-c-mybphosphorothioate DNAs including tetraguanylate form higher order structures under physiologically relevant salt conditions and temperature. First, the identity of the higher order structure was established and was found to be a tetraplex. Employing intracellular (high K+), extracellular (low K+) and normal saline (no K+) salt mixtures, native gel electrophoresis revealed no tetraplex formation at 37 degrees C, the physiologically relevant temperature. On the other hand, tetraplex structure formation was observed at 4 and 23 degrees C. Hence, the potential for these sequences to form tetraplex structures at lower temperatures may not be relevant for their activity in cells and animals at physiological temperature. PMID: 9060425 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 135: Anticancer Res. 1997 Mar-Apr;17(2A):865-71. Cytotoxic effect of sodium nitroprusside on cancer cells: involvement of apoptosis and suppression of c-myc and c-myb proto-oncogene expression. Sumitani K, Kamijo R, Nagumo M. Second Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan. Nitric oxide (NO) is an unstable free radical gas known as an effector molecule of macrophage cytotoxicity against cancer cells. Although several mechanisms of NO-mediated cytotoxicity have been proposed, this phenomenon remains to be characterized in detail. To explore the mechanisms by which NO kills cancer cells, we made use of sodium nitroprusside (SNP), which releases NO in the culture medium. SNP showed a dose-dependent cytotoxic effect on NA cells, an epithelial cancer cell line. When NA cells were killed by SNP, high levels of NO2- (stable end product of NO) were detected in the culture medium. The cell death induced by SNP was mediated by apoptosis, as demonstrated by the presence of nuclear condensation and blebbing of the nuclear membrane, and internucleosomal DNA fragmentation quantified by a specific ELISA. Northern blot analysis revealed that c-myc mRNA expression of NA cells was rapidly reduced by treatment with SNP. RT-PCR analysis showed that c-myb mRNA was expressed in untreated NA cells, and c-myb mRNA level of NA cells was dose-dependently reduced by treatment with SNP. These results indicate that SNP exerts its cytotoxic effect on NA cells through spontaneous release of NO. Cytotoxicity induced by SNP is at least partially mediated via the process known as apoptosis. Our results also suggest that down-regulation of c-myc and c-myb proto-oncogenes might be involved in SNP-induced cytotoxicity. PMID: 9137419 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 136: Exp Nephrol. 1997 Mar-Apr;5(2):126-31. Therapeutic intervention in glomerulonephritis by oligonucleotides. Kashihara N, Maeshima Y, Makino H. Department of Medicine III, Okayama University Medical School, Japan. Publication Types: Review Review, Tutorial PMID: 9108994 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 137: Cell Mol Biol (Noisy-le-grand). 1997 Feb;43(1):115-34. Hemin-induced erythroid differentiation of human myeloleukemia K562 cell line and its modification by bioresponse modifiers. Nakajima O, Iwasaki S, Hashimoto Y. Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan. We have found that protoporphyrin IX, which had been regarded as inactive, induces erythroid differentiation. The differentiation-inducing activities of various hemin-related compounds, including hematoporphyrin IX, mesoporphyrin IX, deuteroporphyrin IX and protoporphyrin IX dimethyl ester, suggested certain structural requirements for the activity: 1) the iron moiety of hemin is not essential, and 2) the propionic acid side chains of hemin play an important role. In addition, we have examined the influence of some bioactive factors on hemin/protoporphyrin IX-induced differentiation of K562 cell line. Retinoids and tubulin-disruptors dose-dependently enhanced hemin/protoporphyrin IX-induced differentiation of K562 cells, though they did not themselves induce differentiation. Retinoid antagonists suppressed hemin-induced differentiation. The effects of hemin and/or retinoids on the mRNA expressions of oncogenes (c-myc and c-myb) and retinoic acid receptor genes (rar alpha and rar beta) of K562 cells were analyzed. We also examined the possible involvement of peripheral-type benzodiazepine receptor (PBR) in hemin/protoporphyrin IX-induced differentiation of K562 cells by the use of its ligands. Diazepam itself was revealed to possess differentiation-inducing activity on K562 cells. The PBR-specific ligands modified hemin-induced differentiation. These results suggest a requirement for retinoids (or retinoid-like cofactors) for hemin/protoporphyrin IX-induced differentiation of K562 cells and the involvement of PBR in erythroid differentiation of K562 cell line. PMID: 9074796 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 138: Exp Cell Res. 1997 Feb 1;230(2):169-80. Differential response of mesoderm- and neural crest-derived smooth muscle to TGF-beta1: regulation of c-myb and alpha1 (I) procollagen genes. Gadson PF Jr, Dalton ML, Patterson E, Svoboda DD, Hutchinson L, Schram D, Rosenquist TH. Department of Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha 68195-6395, USA. Previously, we demonstrated that avian vascular smooth muscle cells (VSMC) derived from embryonic abdominal and thoracic aorta grow differently in the presence of transforming growth factor beta (TGF-beta1) and platelet-derived growth factor (PDGF-BB) (Wrenn et al., In Vitro Cell. Dev. Biol. 29, 73-78, 1992). The thoracic VSMC (N-VSMC) are derived from neural crest, and therefore differentiate from ectoderm; the abdominal VSMC (M-VSMC) are derived from mesoderm. The present study was designed to identify factors that mediate the differential responses of the VSMC to TGF-beta1. We found that TGF-beta1 increased DNA synthesis by approximately sevenfold in N-VSMC. Levels of both alpha1 (I) procollagen and c-myb mRNAs were markedly induced in N-VSMC treated with TGF-beta1. Chimeric plasmids containing up to 3.5 kb of alpha1 (I) procollagen 5' flanking DNA were induced to equivalent levels as procollagen mRNA in N-VSMC. However, TGF-beta1 increased DNA synthesis by threefold in M-VSMC; there was no effect on alpha1 (I) procollagen expression, and c-myb was not expressed, as demonstrated by immunohistochemistry staining and RNA analyses. Antisense c-myb oligodeoxynucleotides blocked the TGF-beta1 induction of alpha1 (I) procollagen and the growth of N-VSMC. The increase in DNA synthesis by M- and N-VSMC was correlated with the secretion of PDGF-AA, and staurosporine and antibodies directed against PDGF-AA suppressed DNA synthesis. Our results demonstrate that TGF-beta1 activity and c-myb expression modulate the expression of alpha1 (I) collagen and cell proliferation in neural crest-derived smooth muscle. The regulation of these events by TGF-beta1 may be important during morphogenesis of blood vessels and vascular diseases. PMID: 9024776 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 139: J Virol. 1997 Feb;71(2):1213-9. Importance of a c-Myb binding site for lymphomagenesis by the retrovirus SL3-3. Nieves A, Levy LS, Lenz J. Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA. All murine leukemia viruses (MuLVs) and related type C retroviruses contain a highly conserved binding site for the Ets family of transcription factors within the enhancer sequences in the viral long terminal repeats (LTRs). The T-cell lymphomagenic MuLV SL3-3 (SL3-3) also contains a c-Myb binding site adjacent to the Ets site. The presence of this Myb site distinguishes SL3 from most other MuLVs. We tested the importance of these two sites for the lymphomagenicity of SL3-3. Mutation of the Ets site had little effect on viral pathogenicity, as it only slightly extended the latency period to disease onset. In contrast, mutation of the Myb site strongly inhibited pathogenicity, as only a minority of the inoculated mice developed tumors in the two mouse strains that were tested. All tumors that were induced by either mutant appeared to be lymphomas, and no evidence for reversion of either mutation was detected. The effects of the Ets and Myb site mutations on transcriptional activity of the SL3 LTR were tested by inserting the viral enhancer sequences into a plasmid containing the promoter region of the c-myc gene linked to a reporter gene. Mutation the Myb site almost eliminated enhancer activity in T lymphocytes, while mutation of the Ets site had smaller effects. Thus, the effects of the enhancer mutations on transcriptional activity in T cells paralleled their effects on viral lymphomagenicity. The absence of the c-Myb site in the LTR enhancer of the weakly lymphomagenic MuLV, Akv, likely contributes to the low pathogenicity of this virus relative to SL3-3. However, Moloney MuLV also lacks the Myb site in its LTR, although it induces T-cell lymphomas with a potency similar to that of SL3-3. Thus, it appears that SL3-3 and Moloney MuLV evolved genetic determinants of T-cell lymphomagenicity that are, at least in part, distinct. PMID: 8995644 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 140: 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] --------------------------------------------------------------- 141: Oncogene. 1997 Jan 9;14(1):123-31. Deregulated expression of the PU.1 transcription factor blocks murine erythroleukemia cell terminal differentiation. Rao G, Rekhtman N, Cheng G, Krasikov T, Skoultchi AI. Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA. Murine erythroleukemia (MEL) cells are transformed erythroid precursors that are blocked from completing the late stages of erythroid differentiation. A frequent event in the generation of these malignant cells is deregulation of the hematopoietic-specific transcription factor PU.1 (Spi-1) by retroviral insertion of the spleen-focus-forming virus component of Friend virus. During chemically induced reinitiation of MEL cell terminal differentiation, expression of PU.1 is rapidly down-regulated, suggesting that PU.1 might interfere with processes required for terminal differentiation of erythroid precursors. To investigate the role of PU.1 in erythroid differentiation we transfected MEL cells with a PU.1 cDNA controlled by the eucaryotic translation elongation factor EF1 alpha promoter. Deregulated expression of PU.1 blocked chemically induced differentiation and terminal cell division. Deregulated expression of two other protooncogenes, c-myc and c-myb, also has been shown to block MEL differentiation. We present evidence that PU.1 inhibits terminal differentiation at an earlier step than c-Myc and c-Myb. Thus reinitiation of MEL cell terminal differentiation appears to be controlled by an ordered program of turning off several protooncogenes. Down-regulation of PU.1 may be a very early step in this program. PMID: 9010239 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 142: 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] --------------------------------------------------------------- 143: 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] --------------------------------------------------------------- 144: J Biol Chem. 1996 Oct 25;271(43):27025-30. Protein kinase C-epsilon is necessary for erythropoietin's up-regulation of c-myc and for factor-dependent DNA synthesis. Evidence for discrete signals for growth and differentiation. Li Y, Davis KL, Sytkowski AJ. Laboratory for Cellular and Molecular Biology, Division of Hematology and Oncology, New England Deaconess Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA. Erythropoietin regulates the transcription of the protooncogenes c-myc and c-myb by discrete protein kinase C (PKC)-dependent and protein serine/threonine phosphatase-dependent pathways, respectively (Spangler, R., Bailey, S. C., and Sytkowski, A. J. (1991) J. Biol. Chem. 266, 681-684; Patel H. R, Choi H.-S, and Sytkowski A. J. (1992) J. Biol. Chem. 267, 21300-21302). In the present study we demonstrate that up-regulation of c-myc requires the PKC-epsilon isoform and that this pathway is required for erythropoietin-induced DNA synthesis (growth) but apparently not for beta-globin expression (differentiation). Treatment of Rauscher murine erythroleukemia cells resulted in phosphorylation of phospholipase C-gamma1 and activation of PKC-epsilon as evidenced by its translocation from soluble to particulate subcellular fractions. Artificial down-regulation of PKC-epsilon with antisense oligodeoxynucleotides blocked erythropoietin's up-regulation of c-myc in a concentration-dependent manner. In contrast, antisense oligodeoxynucleotides to PKC-alpha, -beta, -gamma, -delta, and -zeta had no effect. Although down-regulation of PKC-epsilon blocked the increase in c-myc expression, it did not inhibit erythropoietin induction of beta-globin expression, a marker of erythroid differentiation. However, down-regulation of PKC-epsilon did block factor-dependent DNA synthesis quantified by measurement of [3H]thymidine incorporation into newly synthesized DNA of normal murine erythroid cells. The results are consistent with discrete intracellular signals regulating erythroid cell growth and differentiation. PMID: 8900191 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 145: Biochem Biophys Res Commun. 1996 Oct 14;227(2):589-93. 4-hydroxynonenal specifically inhibits c-myb but does not affect c-fos expressions in HL-60 cells. Barrera G, Pizzimenti S, Serra A, Ferretti C, Fazio VM, Saglio G, Dianzani MU. Dipartimento di Medicina e Oncologia Sperimentale, Universita di Torino, Turin, Italy. 4-Hydroxynonenal, an aldehyde produced from lipid peroxidation of cellular membranes, inhibits growth and induces differentiation of HL-60 human leukemic cell line. Since it is highly unstable in the culture medium, its effectiveness is increased when added repeatedly to the cell suspension. We have previously demonstrated that HNE inhibits c-myc but not N-ras expression in HL-60 cells. Here we investigate its effect on the expression of c-myb and c-fos, two early genes involved in the induction of myeloid and monocytic differentiation. Moreover, since c-fos is directly correlated with the intracellular level of cAMP, we also analysed the cAMP concentration after aldehyde treatment. HNE significantly inhibits c-myb expression during and after repeated treatments. A single administration of 1 microM HNE decreases c-myb mRNA at 1 hour whereas 10 microM HNE inhibits c-myb expression from 3 to 6 hours after treatment, and then the expression returns to the control level. By contrast, c-fos expression and intracellular cAMP concentration do not show any significant change after HNE treatments. PMID: 8878557 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 146: Br J Rheumatol. 1996 Oct;35(10):933-42. Oncoprotein expression in human synovial tissue: an immunohistochemical study of different types of arthritis. Roivainen A, Soderstrom KO, Pirila L, Aro H, Kortekangas P, Merilahti-Palo R, Yli-Jama T, Toivanen A, Toivanen P. Turku Immunology Centre, Department of Medical Microbiology, Turku University, Finland. Based on the fact that synovial lining cells have some properties of transformed-appearing cells, we have examined the expression of Myc, Myb, Fos, Jun and Ras oncoproteins in synovial tissues from patients with different types of arthritis. Formalin-fixed and paraffin-embedded sections of synovial tissue from 12 patients with rheumatoid arthritis (RA), 14 with reactive arthritis (ReA), nine with other seronegative arthritis (OSA), seven with bacterial arthritis (BA), eight with probable bacterial arthritis (PBA) and eight with osteoarthritis (OA) were studied using the immunoperoxidase staining technique. The oncoproteins studied were expressed both in the synovial lining layer and in the sublining layer, consisting of lymphocytes, other inflammatory cells and blood vessels. Among the six disease entities, RA and OA appeared to be the most distinct, whereas the results obtained for ReA and OSA, and on the other hand for BA and PBA, closely resembled each other. The expression of Myc, Myb, Fos and Jun was significantly correlated both to the degree of synovial hypercellularity and the synovial lymphocytic infiltration. For Ras, such a correlation could not be seen. We conclude that we find no evidence of a cell lineage-specific or a disease-specific abnormality of proto-oncogene products in RA, and the expression of these oncoproteins is consistent with inflammation rather than with any primary abnormality of cell growth. PMID: 8883430 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 147: J Biol Chem. 1996 Sep 13;271(37):22697-705. Differential regulation of c-Myb-induced transcription activation by a phosphorylation site in the negative regulatory domain. Miglarese MR, Richardson AF, Aziz N, Bender TP. Departments of Microbiology, University of Virginia, Charlottesville, Virginia 22908, USA. The c-myb protooncogene encodes a highly conserved 75-89-kDa transcription factor that contains three functional domains, an amino-terminal DNA binding domain (DBD), a central acidic transactivation domain, and a carboxyl-terminal negative regulatory domain (NRD). Two acute transforming retroviruses, avian myeloblastosis virus and the E26 leukemia virus, transduced portions of c-myb and encode Myb proteins that are truncated in both the DBD and the NRD. Several conserved potential sites for phosphorylation by proline-directed serine/threonine protein kinases reside in or near the NRD, suggesting that phosphorylation might play a role in regulating c-Myb. We have previously demonstrated that serine 528, located in the NRD, is a target for p42(mapk) in vitro. Serine 528 is phosphorylated in vivo in several cell lines, and substitution of serine 528 to alanine (S528A) resulted in an increased ability of Myb to transactivate a synthetic promoter containing five copies of the mim-1A Myb-responsive element and a minimal herpes tk promoter. We have tested the ability of S528A Myb to transactivate a series of cellular target promoters and report that the serine to alanine substitution increased the ability of Myb to activate transcription from the CD34 promoter but not the c-myc or mim-1 promoters. This suggests that phosphorylation of serine 528 may differentially regulate c-Myb activity at different promoters. The DNA binding and multimerization activities of c-Myb appear to be unaffected by the S528A substitution, suggesting that phosphorylation of serine 528 may mediate its effect on the transcription transactivating activity of c-Myb by regulating interactions with other proteins. PMID: 8798443 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 148: J Lab Clin Med. 1996 Sep;128(3):329-38. Amplification of antibody production by phosphorothioate oligodeoxynucleotides. Branda RF, Moore AL, Lafayette AR, Mathews L, Hong R, Zon G, Brown T, McCormack JJ. Genetics Laboratory, University of Vermont, Burlington 05401, USA. A phosphorothioate oligodeoxynucleotide that is complementary (antisense) to the initiation region of the rev gene of HIV-1 causes hypergammaglobulinemia and splenomegaly in mice, and it induces B cell proliferation and differentiation in mouse spleen mononuclear cells (SMNCs) and human peripheral blood mononuclear cells in vitro. The current studies were performed to investigate the specificity of these immunomodulatory effects. Both the sense and antisense rev oligomers stimulated tritiated thymidine incorporation and secretion of immunoglobulin M (IgM) and immunoglobulin G (IgG) by mouse SMNCs in a concentration-dependent fashion, but the antisense oligomer produced greater immune effects. Studies comparing phosphorothioate oligomers (anti-rev, c-myc, and c-myb) either methylated or unmethylated at CpG dinucleotides showed that methylation effectively abrogated the proliferative effect and tended to reduce the immunoglobulin secretory activity, but the latter was not statistically significant except in the case of IgG in anti-rev oligomer-treated cultures. Mice were injected with the sense or antisense rev oligomers singly or in combination. The animals then were immunized with tetanus toxoid and received a booster 21 days later. Oligodeoxynucleotide-treated mice had significantly higher levels of IgM antibodies on days 28 and 35 and of IgG antibodies on days 14 and 35 as compared with mice that were immunized but received vehicle alone. There was no evidence for additive, synergistic, or antagonistic interactions of the sense and antisense rev oligomers. These results indicate that the unmethylated anti-rev oligomer is the most potent of the phosphorothioate oligomers tested at activating lymphocyte proliferation and differentiation and that a single intravenous injection of this oligodeoxynucleotide augments antibody production to a specific antigen as long as 35 days later. PMID: 8783641 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 149: Cell Growth Differ. 1996 Aug;7(8):1039-50. Terminally differentiated skeletal myotubes are not confined to G0 but can enter G1 upon growth factor stimulation. Tiainen M, Pajalunga D, Ferrantelli F, Soddu S, Salvatori G, Sacchi A, Crescenzi M. Molecular Oncogenesis Laboratory Regina Elena Cancer Center, Rome, Italy. Terminally differentiated cells are specialized cells unable to proliferate that constitute most of the mammalian body. Despite their abundance, little information exists on the characteristics of cell cycle control in these cells and the molecular mechanisms that prevent their proliferation. They are generally believed to be irreversibly restricted to the G0 state. In this report, we define some features of a paradigmatic terminally differentiated system, the skeletal muscle, by studying its responses to various mitogenic stimuli. We show that forced expression of a number of cell cycle-regulatory genes, including erbB-2, v-ras, v-myc, B-myb, ld-1, and E2F-1, alone or in combinations, cannot induce terminally differentiated skeletal muscle cells (myotubes) to synthesize DNA. However, serum-stimulated myotubes display a typical immediate-early response, including the up-regulation of c-fos, c-jun, c-myc, and ld-1. They also elevate the expression of cyclin D1 after 4 hours of serum treatment. All these events take place in myotubes in a way that is indistinguishable from that of quiescent, undifferentiated myoblasts reactivated by serum. Moreover, pretreatment with serum shortens the time required by E1A to induce DNA synthesis, confirming that myotubes can partially traverse G1. Serum growth factors do not activate late-G1 genes in myotubes, suggesting that the block that prevents terminally differentiated cells from proliferating acts in mid-G1. Our results show that terminally differentiated cells are not confined to G0 but can partially reenter G1 in response to growth factors; they contribute to a much-needed definition of terminal differentiation. The important differences in the control of the cell cycle between terminally differentiated and senescent cells are discussed. PMID: 8853900 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 150: Biochem Pharmacol. 1996 Jul 26;52(2):321-9. A cardiotonic steroid bufalin-induced differentiation of THP-1 cells. Involvement of Na+, K(+)-ATPase inhibition in the early changes in proto-oncogene expression. Numazawa S, Inoue N, Nakura H, Sugiyama T, Fujino E, Shinoki M, Yoshida T, Kuroiwa Y. Department of Biochemical Toxicology, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan. Human monocytic leukemia THP-1 cells were induced to differentiate into macrophage-like cells by treatment with cardiotonic steroid bufalin, which was previously shown to interact with the Na+, K+-ATPase with similar kinetics to ouabain, a specific inhibitor of the enzyme. This induction of differentiation was characterized by loss of proliferation, cell adherence, increased ability to reduce Nitro Blue tetrazolium (NBT), and increased expression of interleukin 1 beta (IL-1 beta). During this process, bufalin downregulated c-myb and c-myc expressions and induced c-fos and Egr-1 transcripts. Ouabain also caused similar changes in proto- oncogene expression and induced phenotypic markers of differentiated cells at concentrations comparable to bufalin. The 12-O-tetradecanoyl phorbol-13-acetate resistant THP-1 cell variant, which was unresponsive to this agent as to growth inhibition and proto-oncogene expression, responded to bufalin. The finding that protein kinase inhibitor H7 failed to bufalin-mediated c-fos induction further supports the theory that the signal transduction machinery caused by bufalin is separable from the phorbol ester. The cytotoxic effect of high doses of bufalin apparently disappeared in the medium where Na+ was replaced with choline ions. Furthermore, bufalin failed to induce c-fos expression and to downregulate c-myb transcripts in the low-Na+ medium. These findings indicate that an increased intracellular Na+ concentration resulting from the Na+, K(+)-ATPase inhibition possibly triggers the change in proto-oncogene expression evoked by bufalin. PMID: 8694857 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 151: EMBO J. 1996 Jul 15;15(14):3651-8. A central role for Stat3 in IL-6-induced regulation of growth and differentiation in M1 leukemia cells. Nakajima K, Yamanaka Y, Nakae K, Kojima H, Ichiba M, Kiuchi N, Kitaoka T, Fukada T, Hibi M, Hirano T. Department of Molecular Oncology, Osaka University Medical School, Japan. Interleukin-6 (IL-6) induces either differentiation or growth of a variety of cells. Little is known about the molecular basis of this cellular decision. The family of signal transducer and activator of transcription (Stat) proteins are involved in signaling through a variety of cytokine and growth factor receptors, although their biological roles have not been established. To address whether Stat proteins play roles in IL-6-induced growth or differentiation, we introduced two types of mutant Stat3 acting in a dominant-negative manner into M1 leukemic cells which respond to IL-6 with growth arrest and terminal differentiation. We show that dominant-negative forms of Stat3 inhibited both IL-6-induced growth arrest at G(0)/G1 and macrophage differentiation in the M1 transformants. Blocking of Stat activation resulted in inhibition of IL-6-induced repression of c-myb and c-myc. Furthermore, IL-6 enhanced the growth of M1 cells primarily through shortening the length of the G1 period when Stat3 was suppressed. Thus IL-6 generates both growth-enhancing signals and growth arrest- and differentiation-inducing signals at the same time. Stat3 may be a key molecule which determines the cellular decision from cell growth to differentiation in M1 cells. PMID: 8670868 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 152: J Biol Chem. 1996 Jun 7;271(23):13484-90. Ca2+/calmodulin-dependent and -independent down-regulation of c-myb mRNA levels in erythropoietin-responsive murine erythroleukemia cells. The role of calcineurin. Schaefer A, Magocsi M, Stocker U, Fandrich A, Marquardt H. Department of Toxicology, Hamburg University Medical School, Grindelallee 117, D-20146 Hamburg, Federal Republic of Germany. Down-regulation of c-myb mRNA levels by [Ca2+]i-increasing agents (A23187, thapsigargin, cyclopiazonic acid) and erythropoietin was comparatively studied in the erythropoietin-responsive murine erythroleukemia cell line, ELM-I-1. The Ca2+-induced suppression of c-myb mRNA could be inhibited by the calmodulin antagonists trifluoperazine and calmidazolium, as well as by cyclosporin A, an inhibitor of the Ca2+/calmodulin-dependent protein phosphatase 2B (calcineurin). KN-62, an inhibitor of Ca2+/calmodulin-dependent protein kinases, did not antagonize the Ca2+-mediated decrease in c-myb mRNA. In cyclosporin A-treated ELM-I-1 cells, a close correlation could be demonstrated between the antagonization of the Ca2+ effect on c-myb mRNA levels and inhibition of the calcineurin phophatase activity. On the other hand, FK506, which did not inhibit calcineurin activity in ELM-I-1 cells, failed to prevent the Ca2+-mediated decrease in c-myb mRNA. The erythropoietin-induced down-regulation of c-myb mRNA levels could be demonstrated also in the presence of EGTA and was resistant to calmodulin antagonists and cyclosporin A. In addition, no increase in [Ca2+]i was observed in ELM-I-1 cells in response to erythropoietin. Cyclosporin A inhibited the Ca2+-induced hemoglobin production, while the erythropoietin-mediated increase in hemoglobin synthesis was not affected. The results indicate that the Ca2+-induced decrease in c-myb mRNA and increase in hemoglobin synthesis is mediated by calcineurin, while these effects of erythropoietin occur independently of Ca2+ in ELM-I-1 cells. Calcineurin may be involved in the regulation of c-myb expression in erythroid precursor cells and Ca2+ signals via calcineurin may positively modulate the differentiation inducing action of erythropoietin. PMID: 8662717 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 153: Anticancer Drugs. 1996 May;7(3):293-8. In situ stimulation of topoisomerase II-induced cleavage sites in the c-myc protooncogene by antitumor agent pMC540 is associated with gene expression. Sharma R, Gulliya KS. Baylor University Medical Center, Baylor Research Institute, Dallas, TX 75226, USA. The antitumor activity of pMC540 has been shown to be mediated via its interaction with topoisomerase (Topo) II eventually leading cells into apoptosis. This agent was also found to down regulate the expression of the c-myc oncogene in L1210 leukemia cells. To investigate the possibility that damage within select genomic regions may contribute to the antiproliferative activity of pMC540, differential damage in regions surrounding the c-myc locus as well as other select genes was determined. Southern blot hybridization experiments show that pMC540 treatment induces in situ DNA cleavage products in the 5' end of the c-myc oncogene of L1210 leukemia cells. In cells pre-treated with 50 microM ethidium bromide, an inhibitor of the Topo II-dependent DNA cleavage, a subsequent treatment with pMC540 failed to induce DNA cleavage, suggesting that the cleavage activity of pMC540 was Topo II dependent. pMC540-induced cleavage does not appear to correlate with the over-expression of the c-myc oncogene in these cells as another over-expressed gene c-myb was not affected. Thus, it is proposed that the c-myc gene may be a preferred target for pMC540 may mediated antiproliferative activity. PMID: 8792003 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 154: 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] --------------------------------------------------------------- 155: Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):3963-6. STAT3 activation is a critical step in gp130-mediated terminal differentiation and growth arrest of a myeloid cell line. Minami M, Inoue M, Wei S, Takeda K, Matsumoto M, Kishimoto T, Akira S. Institute for Molecular and Cellular Biology, Osaka University, Japan. Myeloid leukemia M1 cells can be induced for growth arrest and terminal differentiation into macrophages in response to interleukin 6 (IL-6) or leukemia inhibitory factor (LIF). Recently, a large number of cytokines and growth factors have been shown to activate the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway. In the case of IL-6 and LIF, which share a signal transducing receptor gp130, STAT3 is specifically tyrosine-phosphorylated and activated by stimulation with each cytokine in various cell types. To know the role of JAK-STAT pathway in M1 differentiation, we have constructed dominant negative forms of STAT3 and established M1 cell lines that constitutively express them. These M1 cells that overexpressed dominant negative forms showed no induction of differentiation-associated markers including Fc gamma receptors, ferritin light chain, and lysozyme after treatment with IL-6. Expression of either c-myb or c-myc was not downregulated. Furthermore, IL-6- and LIF-mediated growth arrest and apoptosis were completely blocked. Thus these findings demonstrate that STAT3 activation is the critical step in a cascade of events that leads to terminal differentiation of M1 cells. PMID: 8632998 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 156: Nucleic Acids Res. 1996 Apr 15;24(8):1508-14. Oligonucleotide N3'-->P5' phosphoramidates as antisense agents. Gryaznov S, Skorski T, Cucco C, Nieborowska-Skorska M, Chiu CY, Lloyd D, Chen JK, Koziolkiewicz M, Calabretta B. Lynx Therapeutics, Inc., Hayward, CA 94545, USA. Uniformly modified oligonucleotide N3'-->P5' phosphoramidates, where every 3'-oxygen is replaced by a 3'-amino group, were synthesized. These compounds have very high affinity to single-stranded RNAs and thus have potential utility as antisense agents. As was shown in this study, the oligonucleotide phosphoramidates are resistant to digestion with snake venom phosphodiesterase, to nuclease activity in a HeLa cell nuclear extract, or to nuclease activity in 50% human plasma, where no significant hydrolysis was observed after 8 h. These compounds were used in various in vitro cellular systems as antisense compounds addressed to different targeted regions of c-myb, c-myc and bcr-abl mRNAs. C-myb antisense phosphoramidates at 5 microM caused sequence and dose-dependent inhibition of HL-60 cell proliferation and a 75% reduction in c-myb protein and RNA levels, as determined by Western blot and RT-PCR analysis. Analogous results were observed for anti-c-myc phosphoramidates, where a complete cytostatic effect for HL-60 cells was observed at 1 microM concentration for fully complementary, but not for mismatched compounds, which were indistinguishable from untreated controls. This was correlated with a 93% reduction in c-myc protein level. Moreover, colony formation by the primary CML cells was also inhibited 75-95% and up to 99% by anti-c-myc and anti-bcr-abl phosphoramidate oligonucleotides, respectively, in a sequence- and dose-dependent manner within a 0.5 nM-5 microM dose range. At these concentrations the colony-forming ability of normal bone marrow cells was not affected. The presented in vitro data indicate that oligonucleotide N3'-->P5' phosphoramidates could be used as specific and efficient antisense agents. PMID: 8628685 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 157: Dig Dis Sci. 1996 Apr;41(4):660-9. Expression of protooncogene-encoded mRNA by colonic epithelial cells in inflammatory bowel disease. Alexander RJ, Panja A, Kaplan-Liss E, Mayer L, Raicht RF. Department of Veterans Affairs Medical Center, New York, New York 10010, USA. Protooncogenes are cell cycle-related genes that are involved in cell growth of proliferation. Alterations in the level of expression of these genes, or expression of aberrant gene productions, have been observed in tumors and precancerous conditions. To determine if expression of these genes is altered in patients with inflammatory bowel disease (IBD) --who are at risk for development of colon cancer--we assayed transcripts of 15 protooncogenes in colonic epithelial cells of IBD patients and controls. Nine of these genes (H-ras, c-myc, c-fos, c-jun, junB, N-myc, c-abl, c-yes, and p53) were expressed in epithelial cells, whereas two (RB1 and N-ras) were not. expression of four other genes (c-src, K-ras, c-raf, and c-myb) was observed, but the intensity of these bands was too low for densitometric analysis. The steady-state levels of transcripts of H-ras and five nuclear protooncogenes (c-myc, c-fos, c-jun, junB, and N-myc) were lower in epithelial cells from involved or uninvolved IBD samples than in normal epithelial cells from either sporadic colon cancer or diverticulitis patients. The level of c-fos mRNA was two- to threefold higher in involved than in uninvolved areas of the colons of two ulcerative colitis (UC) patients, but not in one Crohn's disease (CD) patient. Message abundance of c-abl transcripts was two- to threefold lower in UC epithelial cells than in either the CD or control samples. The steady-state level of c-yes-encoded mRNA was considerably higher in IBD patients resected for colon cancer than in patients resected for active chronic IBD or in controls. The level of p53 message was constant in these samples. Increased levels of c-fos mRNA in involved UC relative to uninvolved UC may be related to the disease process. Decreased expression of c-abl transcript in UC may be a diagnostic marker for UC and may be related to the rate of cell turnover in these diseases. Enhanced expression of c-yes in IBD patients with tumors compared to active chronic IBD and controls suggests that expression of this gene may be a marker for development of colon cancer in IBD. PMID: 8674385 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 158: EMBO J. 1996 Apr 1;15(7):1557-65. Differentiation and growth arrest signals are generated through the cytoplasmic region of gp130 that is essential for Stat3 activation. Yamanaka Y, Nakajima K, Fukada T, Hibi M, Hirano T. Department of Molecular Oncology, Osaka University Medical School, Japan. Interleukin-6 (IL-6) induces growth arrest and macrophage differentiation through its receptor in a murine myeloid leukaemic cell line, M1, although it is largely unknown how the IL-6 receptor generates these signals. By using chimeric receptors consisting of the extracellular domain of growth hormone receptor and the transmembrane and cytoplasmic domain of gp130 with progressive C-terminal truncations, we showed that the membrane-proximal 133, but not 108, amino acids of gp130 could generate the signals for growth arrest, macrophage differentiation, down-regulation of c-myc and c-myb, induction of junB and IRF1 and Stat3 activation. Mutational analysis of this region showed that the tyrosine residue with the YXXQ motif was critical not only for Stat3 activation but also for growth arrest and differentiation, accompanied by down-regulation of c-myc and c-myb and immediate early induction of junB and IRF1. The tight correlation between Stat3 activation and other IL-6 functions was further observed in the context of the full-length cytoplasmic region of gp130. The result suggest that Stat3 plays an essential role in the signals for growth arrest and differentiation. PMID: 8612579 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 159: Ann Oncol. 1996 Mar;7(3):227-32. 1975-1995 revised anti-cancer serological response: biological significance and clinical implications. Canevari S, Pupa SM, Menard S. Division of Experimental Oncology E, Istituto Nazionale Tumori, Milan, Italy. In the 1970s a considerable amount of work was carried out in an attempt to identify an anti-tumor serological response in cancer patients. These analyses have not been very informative due to the complexity and heterogeneity of the response. More recently, the availability of recombinant molecules, synthetic peptides and analytic and semi-quantitative assays has enabled a better dissection of humoral immunity. Antibodies against intracellular antigens (c-myb, c-myc, p53 and p21 ras) have been found in a significant, albeit varying, proportion of patients bearing various tumors. Association with a poor prognosis is documented for anti-p53 antibodies in breast carcinoma patients. A number of cell surface antigens, including mucins, oncoproteins and carbohydrate antigens have been found to elicit a humoral immune response and, in some instances, circulating immune complexes were observed. A protective role for or, on the other hand, masking effects of such antibodies is still controversial. An indication that a serological response can be beneficial comes from vaccination studies. A significant association between the development of an anti-tumor antigen antibody response and prolonged survival was observed following vaccination of melanoma patients with GM2 or anti-idiotypic antibodies which molecularly mimic tumor-associated antigens. It is to be hoped that in the near future the numerous ongoing immunization trials and prognostic studies demonstrate whether antibody response can exert a protective role in vivo. Publication Types: Review Review, Tutorial PMID: 8740784 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 160: J Cell Physiol. 1996 Feb;166(2):387-96. Interleukin-1 beta suppresses apoptosis in CD34 positive bone marrow cells through activation of the type I IL-1 receptor. Rodriguez C, Lacasse C, Hoang T. Clinical Research Institute of Montreal, University of Montreal, Quebec, Canada. Interleukin-1 is a pleiotropic cytokine that has been shown previously to suppress active cell death in T cells. Two cell surface receptors for interleukin-1 have been identified and their genes cloned, type I (IL-RI) and type II (IL-RII) receptors. In the present study, we provide evidence for a role of interleukin-1 beta in the short-term suppression of cell death both in purified CD34+/Lin- bone marrow precursors and in the GM-CSF dependent cell line TF-1. Several lines of evidence suggest that the biologic effects of IL-1 beta are mediated by activation of type I IL-1 receptors (IL-1RI) and induction of GM-CSF production. First, neutralizing antibodies to IL-1RI but not IL-1RII drastically abrogated cell survival induced by IL-1 beta in CD34+/Lin- cells and TF-1 cells. Second, neutralizing antibodies against GM-CSF abrogate cell survival supported by IL-1 both in CD34+/Lin- bone marrow cells and in the cell line TF-1. Furthermore, exposure of TF-1 cells to IL-1 beta results in a transient accumulation of GM-CSF mRNA, with a peak at 3 h, which was dramatically decreased by neutralizing anti-IL-1R1 antibodies. In contrast, neutralizing anti-IL-1RII did not change the IL-1 induced cell survival of bone marrow cells and was followed by a paradoxical increase in viable cell numbers, in c-myc and c-myb mRNA accumulation in IL-1 treated TF-1 cells. Together our results indicate that the increase in cell survival induced IL-1 beta occurs through binding to IL-1RI and the subsequent production of endogenous GM-CSF. IL-1RII does not appear to be involved in signal transduction in primary CD34+/Lin- cells but could negatively regulate the response to IL-1 beta in TF-1 cells. PMID: 8591999 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 161: Oncogene. 1996 Jan 18;12(2):355-63. B-Myb prevents growth arrest associated with terminal differentiation of monocytic cells. Bies J, Hoffman B, Amanullah A, Giese T, Wolff L. Laboratory of Genetics, National Cancer Institute, Bethesda, Maryland 20892-4255, USA. B-Myb is a transcriptional regulator of gene expression and is highly homologous to c-Myb in its N-terminal DNA binding domain. However, unlike c-myb, whose expression is restricted largely to immature hematopoietic cells, B-myb mRNA has been found to be expressed in all proliferating mammalian cell lines and is clearly regulated in a cell cycle dependent manner. That c-Myb and B-Myb proteins perform different roles in proliferation and/or differentiation is suggested by the redundancy of their expression. It was previously shown that degenerated c-Myb expression can inhibit IL-6 induced terminal differentiation of the leukemia cell line M1. We found that, unlike the downregulation of c-Myb protein which is an early response of progenitor M1 cells to IL-6 treatment, the downregulation of B-Myb occurs late, just prior to terminal differentiation and growth arrest. It was, therefore, of interest to examine the role of the murine B-Myb protein in the proliferation and differentiation of the M1 cells and to compare these effects to those of c-Myb in the same system. Clones ectopically producing B-Myb, like those ectopically expressing c-Myb, proliferated in the presence of the differentiation-inducing agent and did not undergo the programmed cell death which normally follows terminal macrophage differentiation. In addition, the cell-cycle distribution of M1/B-Myb cells was comparable to untreated cells. Although M1/B-Myb and M1/c-Myb clones treated with IL-6 appeared quite immature, differentiation markers were demonstrated to be maintained at near normal levels (e.g. MyD88, Mac-2), or be partially reduced in expression (C3, Fc and Mac-1 receptors) suggesting that the cells had undergone commitment to maturation, but were unable to terminally differentiate. PMID: 8570212 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 162: Crit Rev Oncog. 1996;7(1-2):49-64. Oncogene- and tumor-suppressor gene-related proteins in plants and fungi. Loidl A, Loidl P. Department of Microbiology, University of Innsbruck-Medical School, Austria. Protooncogene- and tumor-suppressor gene proteins serve essential functions in the regulation of proliferation and differentiation of cells. Abnormal regulation or mutation of these genes, or transformation with retroviral homologs, may lead to tumor development in animals. In contrast to vertebrates, only few data on these genes exist in plants and fungi. Plant nuclear protooncogene homologs, such as myb and myc have multiple regulatory functions in metabolic pathways not existing in mammalian cells; they are involved in the complex regulation of anthocyanin (purple pigment) and phlobaphene (red pigment) biosynthesis, lignin production, trichome differentiation, dehydration stress gene expression and seed development. Apart from these well-characterized roles in plant-specific pathways, few experimental data have been reported on a functional significance in growth and development. A screening for nuclear protooncogene- and tumor-suppressor gene-related proteins in the myxomycete Physarum polycephalum revealed the existence of homologs of vertebrate c-myc, c-fos, c-jun, p53, and retinoblastoma proteins during the synchronous cell cycle or sclerotization. The p53 homologs of Physarum and Zea mays were shown to be specific for quiescent stages of their life cycles. Plants and lower eukaryotes, such as fungi, may be useful experimental systems to elucidate novel functions of protooncogene- and tumor-suppressor proteins in cell cycle regulation and development, or to reveal target genes that might be difficult to identify in complex mammalian systems. Recent data indicate that oncogenes and tumor suppressors in animals have more cellular targets than originally proposed; some of these might be as unexpected as in plant secondary metabolism. Publication Types: Review Review, Tutorial PMID: 9109497 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 163: Kidney Blood Press Res. 1996;19(5):221-4. Antisense and the kidney. Oberbauer R, Murer H, Schreiner GF, Meyer TW. Department of Medicine, University of Vienna, Austria. Antisense oligonucleotides are being used as gene-therapeutic agents. This short overview focuses on the in vivo kinetics and on potential in vivo applications for research purposes as well as therapeutic applications. The most promising experimental results have been obtained with oligonucleotides targeted against genes involved in cell proliferation, such as c-myc, c-myb, Kras, and cdc-2. High parenteral doses of such oligonucleotides have limited growth of experimental tumors, and local application of such oligonucleotides has limited neointimal proliferation in injured arteries. Therapeutic use of antisense in the kidney seems more distant. Because proximal tubule cells take up circulating oligonucleotides, transient suppression of proximal tubule message expression may be obtained following parenteral oligonucleotide administration. More sophisticated delivery systems, however, will be required to achieve antisense efficacy over longer periods and in other compartments of the kidney. Publication Types: Review Review, Tutorial PMID: 8956232 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 164: Curr Top Microbiol Immunol. 1996;211:191-9. Retroviral insertional mutagenesis in murine promonocytic leukemias: c-myb and Mml1. Wolff L, Koller R, Bies J, Nazarov V, Hoffman B, Amanullah A, Krall M, Mock B. Laboratory of Genetics, National Cancer Institute, Bethesda, MD 20892-4255, USA. Studies have focused on two genetic loci, c-myb and Mml1, whose activation by retroviral insertional mutagenesis contribute to promonocytic leukemia in our acute monocytic leukemia (AMoL) model. Multiple mechanisms of activation of c-myb by retroviral insertional mutagenesis implicate both transcriptional deregulation and protein truncation in conversion of this proto-oncogene to an oncogene. Because transformation by c-Myb can be viewed as a block to differentiation our studies moved into two in vitro systems to evaluate effects of truncated forms of c-Myb on cytokine induced maturation of myeloid progenitors to the granulocyte and macrophage lineages. Deregulated expression of truncated and full length c-Myb did not result in maintenance of the myelomonocytic progenitor state but rather a block in differentiation at intermediate to late steps in the maturation processes of myelomonocytic cells. Our results argue that inhibition of differentiation is due to c-Myb's ability to maintain the proliferative state of cells. Interestingly, the phenotype of continuously proliferating monocytic cells resembles that of the tumor cell phenotype. Recently we identified a new target of integration, Mml1, which is rearranged in ten promonocytic leukemias that do not have c-myb rearrangements. This locus which was mapped to chromosome 10 is presently being characterized. Publication Types: Review Review, Tutorial PMID: 8585950 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 165: Cell Growth Differ. 1995 Dec;6(12):1559-66. Nitric oxide-releasing agents and cGMP analogues inhibit murine erythroleukemia cell differentiation and suppress erythroid-specific gene expression: correlation with decreased DNA binding of NF-E2 and altered c-myb mRNA expression. Suhasini M, Boss GR, Pascual FE, Pilz RB. Department of Medicine, University of California, San Diego, La Jolla 92093-0652, USA. Differentiation of murine erythroleukemia (MEL) cells induced by hexamethylene bisacetamide (HMBA) and DMSO was inhibited by several structurally unrelated nitric oxide (NO)-releasing agents and two membrane-permeable cGMP analogues. Since the effect of the NO-releasing agents was augmented by a cGMP phosphodiesterase inhibitor, at least some of their effect appeared to be mediated by activation of cytosolic guanylate cyclase. The drugs did not globally block differentiation since hemin-induced differentiation was undisturbed. In HMBA-treated cells, the NO-releasing agents and cGMP analogues reduced beta-globin and delta-aminolevulinate synthetase mRNA expression and inhibited the late down-regulation of c-myb mRNA that is required for HMBA-induced differentiation of MEL cells; the regulation of c-myc mRNA was not changed by the drugs. Nuclear run-off analyses showed that the drugs inhibited the HMBA-induced changes in beta-globin and c-myb transcription rates, and transient transfection of a reporter gene construct demonstrated that the drugs inhibited HMBA-inducible enhancer function of the alpha-globin control region, which contains binding sites for the erythroid transcription factors NF-E2 and GATA-1. The NO-releasing agents and cGMP analogues largely prevented HMBA-induced increases in DNA binding of NF-E2, whereas DNA binding of GATA-1 and SP-1 was not affected. The inhibition of erythroid gene expression by NO and cGMP analogues may be physiologically important under conditions of high NO production by endothelial cells and macrophages, i.e. during acute or chronic inflammation. PMID: 9019161 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 166: J Chemother. 1995 Oct;7(5):449-51. Expression of the multidrug-resistance (MDR) gene in breast cancer. Correnti M, Cavazza ME, Guedez N, Herrera O, Suarez-Chacon NR. Instituto de Oncologia y Hematologia, M.S.A.S., Caracas, Venezuela. Of the approximately 18,000 new cases of cancer in Venezuela each year, only half can be treated with surgery and radiation. The remainder must be treated systematically using chemotherapy or biological response modifiers. It has become evident that any drug resistant human tumors express the MDR1 gene, since MDR1 RNA levels are elevated in many cancers that do not respond to chemotherapy. Human mammary carcinomas have multiple oncogene alterations, the most frequently reported being overexpression of the oncogenes c-myc, int-2, neu and c-myb. Thirteen specimens of mammary cancer were obtained by biopsy of untreated patients in stage IIIB. All these patients received three cycles of FAC or CMF-L+GM-CSF after biopsy. In the slot blot analysis of RNA from invasive carcinomas, MDR1 and c-myc transcripts were detectable at a high level in 30% of tumors. Two patients with increased levels of MDR1 before chemotherapy did not respond to the treatment and distant metastasis and death occurred in these patients. Another patient, MDR1-negative before therapy, did not respond to CMF-1 + GM-CSF and showed high levels of MDR1 transcripts in a second biopsy which was obtained during surgery. Publication Types: Clinical Trial PMID: 8596130 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 167: Leuk Res. 1995 Oct;19(10):749-55. Erythroid differentiation and growth inhibition of K562 cells by 2',5'-dideoxyadenosine: synergism with interferon-alpha. Ogawa K, Tashima M, Takeda Y, Sawai H, Toi T, Sawada H, Maruyama Y, Okuma M. Department of Internal Medicine, Faculty of Medicine, Kyoto University, Japan. We found that 2',5'-dideoxyadenosine (DDA), a P-site specific adenylate cyclase inhibitor, inhibited the growth of K562 cells and caused them to become benzidine positive. The continuous exposure of cells to DDA was needed to recruit cells for growth inhibition and differentiation. Fetal calf or human sera were also necessary for DDA to induce differentiation. DDA at a concentration of 1.5 mM with serum induced 98% of the cells to produce hemoglobin and inhibited their growth to 15% of that of the control. An increase of epsilon-globin mRNA and a decrease of c-myc and c-myb mRNA occurred only during differentiation in the presence of fetal calf serum (FCS). An incubation with DDA and interferon-alpha (IFN-alpha) or hemin synergistically induced more benzidine-positive cells than in the presence of DDA alone, although IFN-alpha did not trigger differentiation by itself. The erythroid differentiation and growth inhibition were, however, not related to a decreased intracellular cyclic AMP (cAMP) concentration induced by DDA. The simultaneous incubation with dibutyryl cyclic AMP (dbc-AMP) and DDA enhanced the effects of DDA. Adenine, a possible metabolite of DDA digestion by purine nucleoside phosphorylase (PNP), also induced erythroid differentiation in K562 cells. However, it did not act synergistically with IFN-alpha. PMID: 7500653 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 168: Br J Rheumatol. 1995 Sep;34(9):805-8. Oncogene expression in synovial fluid cells in reactive and early rheumatoid arthritis: a brief report. Roivainen A, Isomaki P, Nikkari S, Saario R, Vuori K, Toivanen P. Department of Medical Microbiology, Turku University, Finland. Since it has been implied that cellular oncogenes might have a role in the pathogenesis of rheumatoid arthritis (RA), we have examined the expression of c-myc, c-myb, c-fos, c-jun and c-Ha-ras oncogenes in the cells from synovial fluid (SF) and peripheral blood (PB) of patients with reactive arthritis (ReA) and early RA. Oncogene expression was studied using RNA hybridizations with 32P-labelled probes. From the SF, mononuclear and granulocyte cell fractions were used separately. Significant differences between ReA and RA were observed only for c-myb in PB mononuclear cells and c-jun in SF granulocytes. Regarding the expression of c-myc, c-fos and c-Ha-ras oncogenes, no difference between ReA and RA was observed. Comparison to normal controls was made using PB mononuclear cells; only the expression of c-fos tended to be slightly increased in RA, without statistical significance, however. We conclude that oncogene activation in the synovial inflammation is not a phenomenon specific for RA. PMID: 7582717 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 169: Biochem Biophys Res Commun. 1995 Aug 24;213(3):789-95. Coexpression pattern of c-myc associated genes in a small cell lung cancer cell line with high steady state c-myc transcription. Dooley S, Wundrack I, Blin N, Welter C. Department of Human Genetics, Univ of Saarland, Homburg, Germany. The c-Myc protein is involved in cellular transformation and mitogenesis, but also works as a potent inducer of differentiation and programmed cell death. Max as an obligate heterodimeric partner for Myc mediates its functions as a specific transcriptional activator and a transforming protein. Mad and Mxi1 proteins both heterodimerize with Max and compete with each other for limiting amounts of Max. Transcriptional activation by Myc can be suppressed by increasing the amount of Mad or Mxi1. This report shows the expression pattern of these Myc related factors at the mRNA level in a small cell lung cancer (SCLC) cell line (GLC4) which is characterized by c-myc amplification and strong constitutive c-myc overexpression. We found these genes transcriptionally active but uninfluenced from high c-myc transcription. Max was constantly transcribed at a relatively low level during cell cycle progression. Mad and mxi1 mRNA was at a surprisingly high level in proliferating cells. Mad was further upregulated and mxi1 was downregulated to basal levels during serum starvation of the cells. We further analyzed the activity of c-fos, c-jun, c-myb and nm23 which are described to be involved in c-myc transcriptional activation, c-jun and c-fos were not constitutively activated and can be excluded as regulators. High steady state c-myc in contrast influences the serum stimulated transient activation mechanism of these two genes. We identified high copy number nm23 mRNA whose role as a putative c-myc transcriptional activator is under investigation. Our results indicate that constitutive overexpression of c-myc does not require the activity of the nuclear oncogenes tested and that the m-RNA expression pattern of functionally related proteins is not influenced. PMID: 7654239 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 170: Leuk Res. 1995 Aug;19(8):549-56. Bufalin induces apoptosis and influences the expression of apoptosis-related genes in human leukemia cells. Masuda Y, Kawazoe N, Nakajo S, Yoshida T, Kuroiwa Y, Nakaya K. Department of Biological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan. A low concentration of bufalin, a component of bufadienoides in the traditional Chinese medicine chan'su, was shown previously to induce differentiation of a broad range of human leukemia cell lines. In the present study, we found that bufalin at concentrations of 10(-7) M and higher induced apoptosis in human leukemia cells, such as HL60, ML1, but not in mouse leukemia M1 cells. A mere 15 min pretreatment of HL60 cells with 10(-6) M bufalin, followed by incubation for 15 h without bufalin, caused fragmentation of DNA and a decrease in cell viability, indicating that the signal for induction of apoptosis is triggered rapidly upon treatment with bufalin. Bufalin-induced apoptosis in HL60 cells was inhibited by ZnCl2, an inhibitor of endonuclease, but not by cycloheximide, an inhibitor of protein synthesis. Northern blot analysis revealed that the levels of expression of the c-myc and bcl-2 genes in HL60 cells decreased with time after treatment with bufalin. These results suggest that bufalin induces apoptosis specifically in human leukemia cells by altering the expression of these genes involved in apoptosis. PMID: 7658701 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 171: Exp Hematol. 1995 Aug;23(9):970-7. Differential effects of TGF-beta 1 on normal and leukemic human hematopoietic cell proliferation. Murohashi I, Endho K, Nishida S, Yoshida S, Jinnai I, Bessho M, Hirashima K. First Department of Internal Medicine, Saitama Medical School, Japan. We evaluated the effects of transforming growth factor-beta 1 (TGF-beta 1) on the growth of hematopoietic progenitors in normal donors and in patients with hematologic malignancies now designed as clonal disorders of multipotential stem cells. TGF-beta 1 at 80 pM exhibited differential effects on the normal hematopoietic progenitors when cells were stimulated with different growth factors, such as G-CSF, GM-CSF, interleukin-3 (IL-3), or stem cell factor (SCF). The suppressive effect by TGF-beta 1 was increased for growth with GM-CSF, IL-3, and SCF, and growth with G-CSF was unaffected in hematologic malignancies, TGF-beta 1 suppression for growth with G-CSF was increased for essential thrombocythemia (ET) and polycythemia vera; chronic myelogenous leukemia (CML) in chronic phase; CML in accelerated phase; CML in myeloid crisis; myelodysplastic syndrome (MDS) in refractory anemia; MDS in refractory anemia with an excess of blasts; and acute myeloblastic leukemia (AML). In CML-myeloid crisis and AML, TGF-beta 1 almost completely abolished the growth, with some patient-to-patient variation. The mean ED50s for the growth of leukemic blast progenitors were 1.6, 1.2, 0.7, and 0.2 pM in the presence of G-CSF, GM-CSF, IL-3, and SCF, respectively, c-myc and c-myb antisense oligonucleotides significantly suppressed the growth of leukemic blast progenitors, but not that of clonogenic cells from normal donors and patients with ET. We also demonstrated that TGF-beta 1 inhibits mRNA expression by AML blasts for c-myc and/or c-myb. When the data are taken together, growth suppression by TGF-beta 1 appears to increase with the progression of clonal evolution in hematologic malignancies. PMID: 7543418 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 172: Genomics. 1995 Jul 20;28(2):261-72. Structure and chromosomal localization of the human gene of the phosphotyrosyl phosphatase activator (PTPA) of protein phosphatase 2A. Van Hoof C, Aly MS, Garcia A, Cayla X, Cassiman JJ, Merlevede W, Goris J. Afdeling Biochemie, Faculteit Geneeskunde, Katholieke Universiteit Leuven, Belgium. The PTPA gene encodes a specific phosphotyrosyl phosphatase activator of the dimeric form of protein phosphatase 2A. PTPA, cloned from human genomic libraries, is encoded by one single-copy gene, composed of 10 exons and 9 introns with a total length of about 60 kb. The transcription start site was determined, and the 5' flanking sequence was analyzed for its potential as a promotor. This region lacks a TATA sequence in the appropriate position relative to the transcription start, is very GC-rich, and contains upstream of the transcription start four Sp1 sites, a feature common to many TATA-less promotors. Based on the homology with DNA binding consensus sequences of transcription factors, we identified in this promotor region several putative DNA binding sites for transcription factors, such as NF-kappa B, Myb, Ets-1, Myc, and ATF. Transfection experiments with a construct containing the PTPA promotor region inserted 5' of a luciferase reporter gene revealed that the 5' flanking sequence of the PTPA gene indeed displayed promotor activity that seems to be cell-line dependent. By fluorescence in situ hybridization and G-banding, the PTPA gene was localized to the 9q34 region. The PTPA gene is positioned centromeric of c-abl in a region embracing several genes implicated in oncogenesis. PMID: 8530035 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 173: Biochem Biophys Res Commun. 1995 Jul 17;212(2):286-92. Transdermal transport of DNA antisense oligonucleotides by electroporation. Zewert TE, Pliquett UF, Langer R, Weaver JC. Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge 02139, USA. Fluorescein-labeled antisense oligodeoxynucleotides (ODNs) corresponding to the promoters of the protooncogene c-myb (24-mer) and the oncogene c-myc (15-mer) were transported through the human skin in vitro by electroporation. Fluxes of 6.4 +/- 2.1 pM/cm2* hr and 11.5 +/- 3.5 pM/cm2* hr, respectively, were achieved during exponential pulsing [tau pulse = 1.1ms, transdermal voltage (Uskin) = 80V] every five seconds. The flux for Uskin < 70V was undetectable, rapidly increased at 80V, but plateaued at higher values. Fluorescence imaging demonstrated that transport of the ODNs is concentrated in localized transport regions (LTRs)1 approximately 30 microns in diameter. PMID: 7626040 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 174: Anticancer Res. 1995 Jul-Aug;15(4):1285-8. Effect of different cytostatic protocols on oncogene expression in CBA/Ca mice. Ember I, Raposa T, Varga C, Kiss I. Department of Public Health, University Medical School of Pecs, Hungary. In vivo investigations on oncogene action may provide new findings on the toxicology of potential carcinogens. In this study we investigated the early effects of different cytostatic protocols on early oncogene expression in CBA/Ca mice. Most of the examined protocols showed detectable early changes, especially those containing cyclophosphamide. The most frequently involved oncogenes were N-ras, c-myc, and c-myb. PMID: 7654010 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 175: Int J Cancer. 1995 May 29;61(5):698-705. Erratum in: Int J Cancer 1995 Nov 15;63(4):609. Quantitative variation of proto-oncogene and cytokine gene expression in isolated breast fibroblasts. Spanakis E, Brouty-Boye D. Institut d'Oncologie Cellulaire et Moleculaire Humaine, Bobigny, France. Transcripts coding for transcription factors (RB, P53, FOS, MYC, MYB, ERBA, REL), growth factors (FGF1, FGF2, INT2, TGFA, TGFB, PDGF, IGF1, IGF2), interleukins, (IL1, IL2, IL3, IL4, IL6, TNF), growth-factor receptors or cytosolic protein kinases (RAF, PIM, FES, MET, SRC, ROS, TRK, KIT, CSFR, IGFR, PDGFR, EGFR, NEU) were quantified in cultured human mammary fibroblasts from normal tissues, benign tumours, carcinomas and post-radiation fibrosis lesions by slot-blot autoradiography and image analysis. The effects of a differentiating agent (cholera toxin) and of a tumour promoter (12-O-tetradecanoyl-phorbol-13-acetate) were also examined. The drugs modulated the levels of the anti-oncogene transcripts (RB, P53) and of ERBA, REL, RAF, MET, ROS, TRK, CSFR, EGFR, NEU, FGF1, INT2, IGF1, IL1, IL2, IL4 and IL6. Apart from this variation, there were multiple differences in gene expression among normal and pathological cells (concerning all but P53, TGFB and interleukin transcripts) and between sub-types defined by the presence of alpha-sm-actin (myofibroblasts) or EDB-fibronectin (RAF, ROS, FES, KIT, IGFR, NEU, INT2, TGFB, PDGF, IGFs, ILs). It appears, therefore, that mammary stroma progress irreversibly along with the epithelium during tumoral development, and that breast cancer is not only a multi-gene but also a multi-tissue phenotype. PMID: 7768644 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 176: Mol Gen Genet. 1995 May 20;247(4):391-8. Identification of a cis-regulatory region of a gene in Arabidopsis thaliana whose induction by dehydration is mediated by abscisic acid and requires protein synthesis. Iwasaki T, Yamaguchi-Shinozaki K, Shinozaki K. Laboratory of Plant Molecular Biology, Institute of Physical and Chemical Research (RIKEN), Tsukuba Life Science Center, Ibaraki, Japan. In Arabidopsis thaliana, the induction of a dehydration-responsive gene, rd22, is mediated by abscisic acid (ABA) but the gene does not include any sequence corresponding to the consensus ABA-responsive element (ABRE), RYACGTGGYR, in its promoter region. The cis-regulatory region of the rd22 promoter was identified by monitoring the expression of beta-glucuronidase (GUS) activity in leaves of transgenic tobacco plants transformed with chimeric gene fusions constructed between 5'-deleted promoters of rd22 and the coding region of the GUS reporter gene. A 67-bp nucleotide fragment corresponding to positions -207 to -141 of the rd22 promoter conferred responsiveness to dehydration and ABA on a non-responsive promoter. The 67-bp fragment contains the sequences of the recognition sites for some transcription factors, such as MYC, MYB, and GT-1. The fact that accumulation of rd22 mRNA requires protein synthesis raises the possibility that the expression of rd22 might be regulated by one of these trans-acting protein factors whose de novo synthesis is induced by dehydration or ABA. Although the structure of the RD22 protein is very similar to that of a non-storage seed protein, USP, of Vicia faba, the expression of the GUS gene driven by the rd22 promoter in non-stressed transgenic Arabidopsis plants was found mainly in flowers and bolted stems rather than in seeds. PMID: 7770045 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 177: Genes Dev. 1995 May 15;9(10):1250-62. GATA-1 reprograms avian myelomonocytic cell lines into eosinophils, thromboblasts, and erythroblasts. Kulessa H, Frampton J, Graf T. Differentiation Programme, European Molecular Biology Laboratory, Heidelberg, Germany. The transcription factor GATA-1 is expressed in early hematopoietic progenitors and specifically down-regulated in myelomonocytic cells during lineage determination. Our earlier observation that the differentiation of Myb-Ets-transformed chicken hematopoietic progenitors into myeloblasts likewise involves a GATA-1 down-regulation, whereas expression is maintained in erythroid, thrombocytic, and eosinophilic derivatives, prompted us to study the effect of forced GATA-1 expression in Myb-Ets-transformed myeloblasts. We found that the factor rapidly suppresses myelomonocytic markers and induces a reprogramming of myeloblasts into cells resembling either transformed eosinophils or thromboblasts. In addition, we observed a correlation between the level of GATA-1 expression and the phenotype of the cell, intermediate levels of the factor being expressed by eosinophils and high levels by thromboblasts, suggesting a dosage effect of the factor. GATA-1 can also induce the formation of erythroblasts when expressed in a myelomonocytic cell line transformed with a Myb-Ets mutant containing a lesion in Ets. These cells mature into erythrocytes following temperature-inactivation of the Ets protein. Finally, the factor can reprogram a v-Myc-transformed macrophage cell line into myeloblasts, eosinophils, and erythroblasts, showing that the effects of GATA-1 are not limited to Myb-Ets-transformed myeloblasts. Our results suggest that GATA-1 is a lineage-determining transcription factor in transformed hematopoietic cells, which not only activates lineage-specific genetic programs but also suppresses myelomonocytic differentiation. They also point to a high degree of plasticity of transformed hematopoietic cells. PMID: 7758949 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 178: Proc Natl Acad Sci U S A. 1995 May 9;92(10):4601-5. Pluripotent hematopoietic stem cells contain high levels of mRNA for c-kit, GATA-2, p45 NF-E2, and c-myb and low levels or no mRNA for c-fms and the receptors for granulocyte colony-stimulating factor and interleukins 5 and 7. Orlic D, Anderson S, Biesecker LG, Sorrentino BP, Bodine DM. Hematopoiesis Section, National Center for Human Genome Research, National Institutes of Health, Bethesda, MD 20892, USA. Pluripotent hematopoietic stem cells (PHSCs) were highly enriched from mouse bone marrow by counterflow centrifugal elutriation, lineage subtraction, and fluorescence-activated cell sorting based on high c-kit receptor expression (c-kitBR). We used reverse transcriptase polymerase chain reaction to assay the c-kitBR subset and the subsets expressing low (c-kitDULL) and no (c-kitNEG) c-kit receptor for expression of mRNA encoding hematopoietic growth factor receptors and transcription factors. The c-kitBR cells had approximately 3.5-fold more c-kit mRNA than unfractionated bone marrow cells. The c-kitDULL cells had 47-58% of the c-kit mRNA found in c-kitBR cells and the c-kitNEG cells had 4-9% of the c-kit mRNA present in c-kitBR cells. By comparing mRNA levels in c-kitBR cells (enriched for PHSCs) with those of unfractionated bone marrow, we demonstrated that c-kitBR cells contained low or undetectable levels of mRNA for c-fms, granulocyte colony-stimulating factor receptor, interleukin 5 receptor (IL-5R), and IL-7R. These same cells had moderate levels of mRNA for erythropoietin receptor, IL-3R subunits IL-3R alpha (SUT-1), AIC-2A, and AIC-2B, IL-6R and its partner gp-130, and the transcription factor GATA-1 and high levels of mRNA for transcription factors GATA-2, p45 NF-E2, and c-myb. We conclude from these findings that PHSCs are programmed to interact with stem cell factor, IL-3, and IL-6 but not with granulocyte or macrophage colony-stimulating factor. These findings also indicate that GATA-2, p45 NF-E2, and c-myb activities may be involved in PHSC maintenance or proliferation. PMID: 7538677 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 179: Proc Natl Acad Sci U S A. 1995 Apr 25;92(9):4051-5. The antiproliferative activity of c-myb and c-myc antisense oligonucleotides in smooth muscle cells is caused by a nonantisense mechanism. Burgess TL, Fisher EF, Ross SL, Bready JV, Qian YX, Bayewitch LA, Cohen AM, Herrera CJ, Hu SS, Kramer TB, et al. Department of Mammalian Cell Molecular Biology, Amgen Inc., Amgen Center, Thousand Oaks, CA 91320-1789, USA. Smooth muscle cell (SMC) proliferation is thought to play a major role in vascular restenosis after angioplasty and is a serious complication of the procedure. Developing antisense (AS) oligonucleotides as therapeutics is attractive because of the potentially high specificity of binding to their targets, and several investigators have reported inhibition of SMC proliferation in vitro and in vivo by using AS strategies. We report here the results of our experiments on vascular SMCs using AS oligonucleotides directed toward c-myb and c-myc. We found that significant inhibition of SMC proliferation occurred with these specific AS sequences but that this inhibition was clearly not via a hybridization-dependent AS mechanism. Rather, inhibition was due to the presence of four contiguous guanosine residues in the oligonucleotide sequence. This was demonstrated in vitro in primary cultures of SMCs and in arteries ex vivo. The ex vivo model developed here provides a rapid and effective system in which to screen potential oligonucleotide drugs for restenosis. We have further explored the sequence requirements of this non-AS effect and determined that phosphorothioate oligonucleotides containing at least two sets of three or four consecutive guanosine residues inhibit SMC proliferation in vitro and ex vivo. These results suggest that previous AS data obtained using these and similar, contiguous guanosine-containing AS sequences be reevaluated and that there may be an additional class of nucleic acid compounds that have potential as antirestenosis therapeutics. PMID: 7732029 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 180: FEBS Lett. 1995 Apr 3;362(2):215-9. Studies on the promoter of the Arabidopsis thaliana cdc2a gene. Chung SK, Parish RW. School of Botany, La Trobe University, Bundoora, Victoria, Australia. The 5' flanking (promoter) region of the Arabidopsis thaliana cdc2a gene was cloned and sequenced. A number of putative regulatory motifs were identified including one Myc and three Myb protein binding sequences plus one abscisic acid and two auxin responsive elements. One of the three Myb protein binding sequences is positioned within an auxRE. Promoter-GUS fusions were introduced into plants to study the role of two promoter regions in regulating gene expression. Absence of one Myb binding sequence and the auxRE containing a Myb binding sequence resulted in a significant reduction in expression levels as did a deletion involving the Myc and the third Myb binding sequences along with the second auxRE. However, no changes in expression patterns were observed. The results were quantified using transgenic root cultures. PMID: 7720875 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 181: Cell Growth Differ. 1995 Mar;6(3):239-50. Apoptosis in Pam212, an epidermal keratinocyte cell line: a possible role for bcl-2 in epidermal differentiation. Marthinuss J, Lawrence L, Seiberg M. Skin Biology Research Center, R. W. Johnson Pharmaceutical Research Institute, Raritan, New Jersey 08869, USA. Programmed cell death is a controlled process that leads to the elimination of single cells via apoptosis, a mode of cell death with a characteristic morphology. During epidermal differentiation, keratinocytes migrate outward to become terminally differentiated cornified cells in a process involving programmed cell death pathway(s) and apoptosis. The molecular mechanisms regulating epidermal differentiation and apoptosis have not yet been elucidated. Here we show that a mouse keratinocyte cell line, Pam212, undergoes spontaneous apoptosis in culture. Apoptosis of Pam212 cells is demonstrated by both morphology and DNA oligonucleosomal degradation. The expression of bcl-2, a gene implicated in the negative control of apoptosis, was down-regulated in these cells by transfecting a bcl-2-antisense expression vector. The cells that down-regulate bcl-2 expression exhibit enhanced apoptosis and further progress in the epidermal differentiation pathway. We analyzed the expression patterns of several genes that have been implicated in apoptosis in other systems. We show that the mRNA levels of c-myc, c-myb, c-fos, tumor necrosis factors (TNF) alpha and beta, TNF receptors I and II, interleukin 1 alpha, IFN-gamma, and transforming growth factor beta increase in the antisense-transfected cells. We suggest that bcl-2 influences epidermal differentiation in Pam212 keratinocyte cells, and maybe in vivo, by negatively regulating several genes that are involved in apoptosis. PMID: 7794792 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 182: Circ Res. 1995 Feb;76(2):176-82. c-myc in vasculoproliferative disease. Edelman ER, Simons M, Sirois MG, Rosenberg RD. Harvard University-Massachusetts Institute of Technology, Division of Health Sciences and Technology, Cambridge 02139. Antisense oligonucleotides to genes central to cellular proliferation have suppressed smooth muscle cell growth in vitro and in vivo. We now report that although the response of cultured smooth muscle cells to antisense oligonucleotides to c-myc and c-myb is identical, the response of the injured arterial wall to these oligomers depends on the kinetics of gene expression and oligonucleotide delivery. Two different antisense oligonucleotides to each oncogene were administered to the perivascular aspect of injured rat carotid arteries via polymer-based delivery systems. The acute release of antisense oligonucleotides from the Pluronic gels reduced in vitro cell growth 54.8% with c-myc and 56.9% with c-myb. The more sustained release from ethylene vinyl acetate copolymer (EVAc) matrices was slightly less efficient, inhibiting proliferation 47.3% and 43.3%, respectively. However, although both EVAc and Pluronic release of c-myb antisense oligonucleotide sequences inhibited intimal hyperplasia 2 weeks after injury, only the more prolonged EVAc matrix release of antisense oligonucleotide to c-myc was effective. The failure of the short course of c-myc oligomer release from Pluronic gels stemmed from early successful suppression with late loss of regulation and not from inactivation of the antisense oligonucleotide within the polymeric gel. Within 24 hours of injury, Pluronic-based release of c-myc antisense oligomers reduced mRNA levels in the tunica media 2.5-fold and immunocytochemical identification of c-myc expression by 98.8%. As a result, the number of proliferating cells was decreased 6.5-fold 3 days after injury.(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 7834827 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 183: Cancer Res. 1995 Feb 1;55(3):501-4. Acceleration of apoptosis in transforming growth factor beta 1-treated M1 cells ectopically expressing B-myb. Bies J, Wolff L. Laboratory of Genetics, National Cancer Institute, NIH, Bethesda, Maryland 20892. Inappropriate expression of genes involved in cell proliferation can result in altered regulation of apoptosis, a process of programmed cell death. Since B-myb has recently been implicated in the cell cycle progression we wanted to examine its role in the apoptotic process. For this purpose we used transforming growth factor beta 1 (TGF-beta 1)-treated M1 myeloid leukemia cell lines that continuously express murine B-myb. It was found that in cells overexpressing B-myb, TGF-beta 1-induced apoptosis was accelerated as assessed by cell viability and DNA fragmentation into nucleosomal fragments. A DNA ladder was detected after 24 h of TGF-beta 1 treatment in these cells, whereas it was not detected until after 36 h in the parental M1 cells. It was further determined by Northern blot analysis that this higher sensitivity of B-myb overexpressing clones was not due to a change in the expression of TGF-beta receptor type I or in the kinetics of the regulation of c-myc, c-myb, bcl-2, and/or bax. PMID: 7834617 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 184: EMBO J. 1995 Feb 1;14(3):473-83. Differential roles of PI3-kinase and Kit tyrosine 821 in Kit receptor-mediated proliferation, survival and cell adhesion in mast cells. Serve H, Yee NS, Stella G, Sepp-Lorenzino L, Tan JC, Besmer P. Molecular Biology Program, Sloan Kettering Institute, New York, NY 10021. The pleiotropic effects of the Kit receptor system are mediated by Kit-Ligand (KL) induced receptor autophosphorylation and its association with and activation of distinct second messengers, including phosphatidylinositol 3'-kinase (PI3-kinase), p21ras and mitogen-activated protein kinase (MAPK). To define the role of PI3-kinase, p21ras and MAPK in Kit-mediated cell proliferation, survival and adhesion in bone marrow-derived mast cells (BMMC), mutant Kit receptors were expressed in Wsh/Wsh BMMC lacking endogenous c-kit expression. The introduction of both murine Kit(S) and KitL (isoform containing a four amino acid insert) into Wsh/Wsh BMMC restored KL-induced proliferation, survival and adhesion to fibronectin, as well as activation of PI3-kinase, p21ras and MAPK, and induced expression of c-fos, junB, c-myc and c-myb mRNA. Substitution of tyrosine 719 in the kinase insert with phenylalanine (Y719F) abolished PI3-kinase activation, diminished c-fos and junB induction, and impaired KL-induced adhesion of BMMC to fibronectin. In addition, the Y719F mutation had partial effects on p21ras activation, cell proliferation and survival, while MAP kinase activation was not affected. On the other hand, Y821F substitution impaired proliferation and survival without affecting PI3-kinase, p21ras and MAPK activation, and induction of c-myc, c-myb, c-fos and c-jun mRNA, while KL-induced cell adhesion to fibronectin remained intact. In agreement with a role for PI3-kinase in Kit-mediated cell adhesion, wortmannin blocked Kit-mediated cell adhesion at concentrations known to specifically inhibit PI3-kinase. We conclude, that association of Kit with p85PI3-K, and thus with PI3-kinase activity, is necessary for a full mitogenic as well as adhesive response in mast cells. In contrast, tyrosine 821 is essential for Kit-mediated mitogenesis and survival, but not cell adhesion. PMID: 7532131 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 185: Leukemia. 1995 Jan;9(1):146-54. DMSO-like rapid decrease in c-myc and c-myb mRNA levels and induction of differentiation in HL-60 cells by the anthracycline antitumor antibiotic aclarubicin. Stocker U, Schaefer A, Marquardt H. Department of Toxicology, Hamburg University Medical School, Germany. The anthracycline antitumor antibiotic aclarubicin is known to induce granulocytic differentiation in the human myeloid leukemia cell line HL-60. We investigated whether this effect is accompanied by changes in the expression of the protooncogenes c-myc and c-myb. Treatment of HL-60 cells with aclarubicin, 50 nM, caused a rapid decrease in c-myc and c-myb mRNA levels within 1 h and 2 h, respectively. In parallel, we demonstrated a strong induction of superoxide-anion production on day 8 of treatment. The kinetics of the effect of aclarubicin on c-myc and c-myb expression were comparable to those associated with the dimethylsulfoxide-induced granulocytic differentiation in this cell line, or to those observed following a chase with actinomycin D, 4 microM. Since aclarubicin partially inhibited total- and poly(A)(+)-RNA synthesis, this macromolecular synthesis inhibition may be causally related to the decrease in c-myc and c-myb mRNA levels. In contrast, the conventional anthracycline doxorubicin, which did not initiate differentiation, failed to affect c-myc or c-myb mRNA levels even in high cytotoxic concentrations, indicating that the suppression of c-myc and c-myb mRNA levels may be an early differentiation-related effect of aclarubicin. On the other hand, actinomycin D, 12.5 nM, and novobiocin, 300 microM, two other known inducers of granulocytic differentiation in HL-60 cells, did not induce an early decrease in c-myb or c-myc expression. Therefore, the immediate suppression of c-myc and c-myb mRNA levels, apparently, is not an obligatory step in chemically induced myeloid differentiation in HL-60 cells, but the common phenomenon in DMSO- and aclarubicin-induced differentiation. PMID: 7845009 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 186: J Invest Dermatol. 1995 Jan;104(1):78-82. Changes in expression of apoptosis-associated genes in skin mark early catagen. Seiberg M, Marthinuss J, Stenn KS. Skin Biology Research Center, R.W. Johnson Pharmaceutical Research Institute, Raritan, NJ 08869-0602. Programmed cell death is central to hair biology, as the hair follicle undergoes cycles of growth (anagen), regression (catagen), and rest (telogen). During catagen, the hair follicle shortens via a pathway of programmed cell death and apoptosis. The molecular mechanisms involved in this process have not been elucidated yet. Using reverse transcriptase-polymerase chain reaction, we examined in this study the expression in total skin, throughout one hair cycle, of a series of regulatory genes associated with apoptosis. We show that gene expression within skin is hair-cycle-dependent. Transforming growth factor-beta was expressed immediately before catagen; therefore, it might be involved in the early signaling of this process. Tumor necrosis factor-beta was expressed during catagen and might be involved in follicular apoptosis. Several proto-oncogenes and transcription factors have been described in the regulation of apoptosis in other systems. Here we show that the transcript levels of c-myc, c-myb, and c-jun changed immediately before or during early catagen and thus could be involved in the signaling or regulation of catagen. Levels of p53 remained constant throughout anagen and catagen, suggesting that p53 is not involved in the developmentally induced apoptosis of the hair follicle. The variable expression throughout the hair cycle of the genes described demonstrates the dynamic changes of the skin and underscores the importance of studying the complete hair cycle when characterizing any molecule in skin. PMID: 7798646 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 187: Sheng Li Ke Xue Jin Zhan. 1995 Jan;26(1):45-9. [Psychoneuroimmunological effects of morphine and the immunoprotection of Ganoderma polysaccharides peptide in morphine-dependent mice] [Article in Chinese] Lu ZW. Department of Pharmacology, School of Basic Medical Sciences, Beijing Medical University. Different kinds of single, multiple, acute or chronic administrations of morphinized animal models were established, with which a series of experiments in both in vivo and in vitro systems as well as molecular levels were pharmacologically designed to investigate the psychoneuroimmunological effects of morphine (Mor) and the immunoprotection of Ganoderma polysaccharides peptide (GPP) in Mor-dependent mice. It was first discovered that both c-myb and c-myc mRNA expression in splenocytes of repetitive Mor-treated mice were detected to be significantly decreased, and that GPP could induce restoration of several immunologic parameters depressed by Mor treatment to or even beyond normal levels. This provides the experimental animal evidence that immune response modifiers such as GPP could be of potential application in controlling abuse of opiates-induced immunodeficiency. PMID: 7604222 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 188: Br J Haematol. 1995 Jan;89(1):72-8. PIG-A, DAF and proto-oncogene expression in paroxysmal nocturnal haemoglobinuria-associated acute myelogenous leukaemia blasts. Stafford HA, Nagarajan S, Weinberg JB, Medof ME. Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106. Failed surface expression of the complement decay-accelerating factor (DAF) due to mutation of the PIG-A gene is a hallmark of affected paroxysmal nocturnal haemoglobinuria (PNH) blood elements. Previous findings that acute myelogenous leukaemia (AML) blasts evolving in a PNH patient differed from idiopathic AML blasts in that they exhibited DAF negativity suggested that the leukaemic blasts derived from an affected PNH cell. To investigate whether these cells differ from untransformed PNH cells in PIG-A genetic alterations or in DAF mRNA processing, or are distinguishable from conventional AML blasts in proto-oncogene activation or chromosomal structure, their DNA and RNA were examined using PIG-A, DAF and proto-oncogene probes and their karyotype was analysed. Analyses of the PIG-A genome revealed dual exchanges of A1110-->G and T1130-->A resulting in conversions of T370 to R and I377 to N in the coding region but no deletions or rearrangements. Investigations of DAF mRNA processing showed mRNA species differing in 3' UT regions from those in untransformed cells but similar to those in DAF-positive leukaemia cell lines. Studies of c-myb, c-myc, c-fos and c-fms showed no gross genetic alterations, amplifications or variations in mRNA transcripts deriving from these genes. Karyotypic analysis showed no alterations. The results indicate that in AML blasts evolving in PNH: (1) the PIG-A genome exhibits multiple point mutations but no gross genetic changes; (2) DAF mRNA transcripts exhibit differentiation-dependent variations that do not affect GPI-anchoring; (3) c-myb, c-myc, c-fos and c-fms activation show no differences from idiopathic AML; and (4) no karyotypic abnormalities are associated with AML transformation. PMID: 7530480 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 189: J Cell Physiol. 1994 Dec;161(3):490-500. c-Ha-rasEJ transfection of rat aortic smooth muscle cells induces epidermal growth factor responsiveness and characteristics of a malignant phenotype. Sadhu DN, Lundberg MS, Burghardt RC, Ramos KS. Department of Veterinary Physiology, Texas A&M University, College Station 77843. Although the role of several protooncogenes, including sis, myc, and myb in the regulation of growth and differentiation of vascular cells has been examined in some detail, limited information is available on the contribution of ras genes to these processes. In the present studies the influence of oncogenic ras transfection on the phenotypic expression of rat aortic smooth muscle cells (SMCs) was examined. Cultured rat aortic SMCs during early passage (P4) were transfected by lipofection with c-Ha-rasEJ in a pSV2 neo vector or with pSV2 neo vector alone. Stable transfectants were selected in G418 over a 6-week period. Oncogene-transfected cells (ras-LF-1) exhibited differences in morphology and growth pattern relative to vector controls (neo-LF-1), or naive SMCs, including the development of prominent processes and the appearance of focal cellular arrangements giving rise to latticelike structures. Southern analysis revealed multiple integration of oncogenic ras in ras LF-1 cells. Transfection of c-Ha-rasEJ was associated with a twofold increase in p21 levels relative to pSV2 vector controls demonstrating that exogenous ras was expressed in these cells. Overexpression of ras p21 afforded SMCs a lower serum requirement for growth compared to vector controls, anchorage independent growth on soft agar, and acquisition of epidermal growth factor (EGF) responsiveness. Stimulation of serum-deprived SMCs with 5% fetal bovine serum (FBS) increased steady-state levels of c-Ha-ras mRNA in both ras-LF-1 and neo-LF-1 but ras induction was more pronounced in ras-transfected cells. alpha-smooth muscle (SM) actin gene expression was markedly reduced in ras-transfected cells relative to vector controls. These results show that transfection of c-Ha-rasEJ into aortic SMCs induces an altered phenotypic state characterized by alterations in growth factor-related signal transduction and tumorigenic potential. PMID: 7962130 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 190: Pathologe. 1994 Dec;15(6):321-30. [Oncogenes and tumor suppressor genes in the pathogenesis of lung tumors] [Article in German] Wiethege T, Voss B, Muller KM. Institut fur Pathologie, Berufsgenossenschaftliche Kliniken Bergmannsheil, Bochum. The recent results obtained from investigations based on molecular biological techniques have led to a better understanding of recurrent genetic causes important for the pathogenesis of tumors. Several genes have been identified as being involved in the development of cancer. In many cases, the activation of oncogenes or the inactivation of tumor-suppressor genes is the predominant reason for cancerogenic cell transformation. Functional dysregulation is frequently the consequence of mutations, resulting in an alteration of the primary structure of the DNA. As our understanding of the nature, function, and interaction of these genes evolves, new opportunities for early diagnosis, classification, prevention, and treatment of malignant tumors will arise. The present report summarizes the current molecular biological aspects of several oncogenes (erbB, ras, myc, raf, fos, jun, bcl, mdm2, myb, kit CSF1R, met) and tumor suppressor genes (p53, rb, mts) involved in lung-cancer development with respect to the pathology of lung tumors, including the importance of these genes as far as the clinical course of the disease is concerned. Publication Types: Review Review, Tutorial PMID: 7855100 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 191: Immunol Invest. 1994 Nov;23(6-7):457-72. Macrophage priming and activation during fibrosarcoma growth: expression of c-myb, c-myc, c-fos, and c-fms. Alleva DG, Askew D, Burger CJ, Elgert KD. Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0406. Macrophages (M phi)3 function by a two-step process that includes priming (induction of cytokine and enzyme mRNA) and activation (production of effector molecules). The initial steps in M phi priming involve the expression of certain proto-oncogenes that regulate expression of other genes. Because tumor growth primes M phi to produce several suppressor monokines, we determined if cancer induced M phi expression of these proto-oncogenes. Unstimulated peritoneal M phi from tumor-bearing hosts (TBH) constitutively expressed the proto-oncogenes c-fms, c-fos, c-myc, and c-myb, whereas normal host (NH) M phi had little or no expression of these proto-oncogenes. When M phi were given a 24-h adherence priming stimulus, NH M phi expressed c-fms and c-fos at levels equivalent to TBH M phi constitutive expression. Adherence had little or no effect on c-fms and c-fos expression in TBH M phi or on NH and TBH M phi c-myc expression. c-myb expression was not induced in NH M phi during adherence and was strongly decreased in TBH M phi. Activation with a 1-h lipopolysaccharide-treatment increased NH and TBH M phi expression of c-fms, c-fos, and c-myc, with higher expression of these proto-oncogenes in TBH M phi. Activation failed to induce c-myb expression in NH M phi and completely inhibited expression in TBH M phi. Because c-fms, c-fos, and c-myc are normally expressed early during M phi activation, our results suggest that tumor growth primes M phi by inducing expression of these proto-oncogenes. c-myb is expressed in immature M phi and is downregulated during M phi activation. These observations explain why NH M phi expression of c-myb was not induced and are consistent with reports that suggest TBH M phi have not reached full developmental maturity. The induction of M phi proto-oncogene expression during cancer may put M phi in a primed state, which leads to earlier and stronger production of adverse suppressor and cytotoxic molecules. PMID: 7851963 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 192: Hepatology. 1994 Nov;20(5):1109-14. Expression of the c-myc protooncogene product in cells infected with the hepatitis delta virus. Tappero G, Natoli G, Anfossi G, Rosina F, Negro F, Smedile A, Bonino F, Angeli A, Purcell RH, Rizzetto M, et al. Clinica Medica Generale, University of Turin Medical School, Orbassano, Italy. The intrahepatic accumulation of the c-myc protooncogene product was observed on immunofluorescence in each of six patients with chronic hepatitis delta virus infection who exhibited the hepatitis D antigen in their livers. The c-myc product was stained in the same nuclei that contained the hepatitis D antigen. C-myc was not observed in acute hepatitis D or in cases of chronic hepatitis delta virus infection without expression of the hepatitis D antigen. The protooncogene product was detected in only 1 of 32 viral and nonviral liver disorders unrelated to hepatitis delta virus. To confirm these observations, we transfected HBsAg-positive (PCL/PRF/5) and HBsAg-negative (HepG2) transformed liver cell lines with a plasmid containing a hepatitis delta virus cDNA trimer under the control of the SV40 early enhancer/promoter sequences. Whereas baseline c-myc expression was barely detectable in mock-transfected PLC/PRF/5 or HepG2 cells, strong c-myc nuclear fluorescence was observed when these same cells were transfected with the hepatitis D antigen expression vector. Similar results were obtained after infection of HeLa cells with a recombinant vaccinia virus expressing the hepatitis D antigen. Detection of c-myc mRNA sequences by means of in situ hybridization suggested that the c-myc product accumulation was not due to increased amounts of its mRNA. The c-myc protein accumulates selectively in the livers of patients with chronic hepatitis delta virus infection and in the same nuclei that contain the hepatitis D antigen. The expression of c-myc in hepatitis D antigen-containing cells does not require the presence of hepatitis B virus infection. PMID: 7523269 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 193: Cancer Res. 1994 Oct 1;54(19):5086-91. Identification of frequent novel genetic alterations in small cell lung carcinoma. Levin NA, Brzoska P, Gupta N, Minna JD, Gray JW, Christman MF. Department of Radiation Oncology, University of California, San Francisco 94143. We have performed a comprehensive analysis of the DNA copy number changes that occur in 18 small cell lung carcinoma cell lines using comparative genomic hybridization (Kallioniemi et al., Science (Washington DC). 258: 818-821, 1992). DNA copy number abnormalities detected in this study include previously identified increases at 1p22-32 (L-myc), 2p24-25 (N-myc), and 8q24 (c-myc) and decreases at 17p13 (p53), 13q14 (RB), and 3p. In addition, novel DNA copy number increases were detected at 5p, 1q24, and Xq26, and novel decreases were found at 22q12.1-13.1, 10q26, and 16p11.2. Many of the most common DNA copy number changes revealed are at loci not previously recognized to be important in small cell lung cancer. In addition, a number of the DNA copy number changes, including increases at 1p22-32, 2p24-25, and 3q22-25 and a decrease on 18p, were found to occur preferentially in small cell lung carcinoma lines of the "variant" phenotype. This correlation suggests that genes may reside at these loci whose overexpression or inactivation contributes to the radiation resistance or aggressive growth phenotypes characteristic of this subtype of small cell lung carcinoma. PMID: 7923122 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 194: J Cell Sci. 1994 Oct;107 ( Pt 10):2761-8. The role of duplication of tumour-derived chromosome 15 carrying the rearranged pvt-1 gene in the transformed phenotype of YACUT T-cell lymphoma x G4 T-cell line somatic cell hybrids in dictating the terminal differentiation program of the parental G4 cell. Kubota K, Nakazato K. Department of Microbiology, Kitasato University School of Medicine, Kanagawa, Japan. Fusion of the YACUT T-cell lymphoma with the Mls-1a-antigen-specific non-tumorigenic T-cell line G4 was previously reported to produce growth-arrested hybrids that could be induced to proliferate in the presence of Mls-1a antigen. The proliferation-suppressed hybrid lines exhibited phenotypic changes as follows: the usually high levels in YACUT of J11d antigen, IL-2 receptor, and c-myb expression, which are markers of immature T cells, were all down-regulated; the G4 T-cell function, i.e., contact helper activity for B-cell proliferation in T/B cell collaboration, was retained. Furthermore, fusion of the YACUT lymphoma with a killer T-cell line produced growth-arrested and tetraploid somatic cell hybrids having killer activity. Thus, in addition to the transformed phenotype (autonomous proliferation in vitro), the antigen-specific non-tumorigenic T-cell line genomes introduced into the YACUT lymphoma suppressed the immature phenotypes of YACUT and imposed their own programming of terminally differentiated traits on the hybrids. Prolonged growth of the proliferation-suppressed hybrid lines by repeated antigenic stimulation was previously reported to result in the appearance of transformed hybrids, which was accompanied by both a reversion of c-myc expression to the levels of YACUT and an increase in the number of chromosome 15. The present study revealed that the amplification of chromosome 15 resulted from the duplication of the tumour-derived chromosome 15 carrying the rearranged pvt-1 gene. However, the differentiated phenotypes of the hybrids remained mostly unchanged upon cell transformation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 7876344 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 195: Curr Opin Genet Dev. 1994 Oct;4(5):647-51. Cell fate and cell morphogenesis in higher plants. Schiefelbein JW. Department of Biology, University of Michigan, Ann Arbor 48109-1048. The differentiation of plant cells depends on the regulation of cell fate and cell morphogenesis. Recent studies have led to the identification of mutants and the cloning of genes that influence these processes. In several instances, the genes encode products with homeodomains or Myb or Myc DNA-binding domains. Publication Types: Review Review, Tutorial PMID: 7849503 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 196: Cell Growth Differ. 1994 Aug;5(8):863-71. Avian myeloblastic cell lines transformed by two nuclear oncoproteins, P135gag-myb-ets and p61/63myc: a model of retinoic acid-induced differentiation not abrogated by v-erbA. al Moustafa AE, Gautier R, Saule S, Dieterlen-Lievre F, Cormier F. Institut d'Embryologie Cellulaire et Moleculaire, Nogent-sur-Marne, France. We previously demonstrated that the retroviral construct MHE226 transducing both the P135gag-myb-ets and p61/63myc nuclear proteins induces solid hemopoietic tumors in early chicken embryos. In the present paper, we report the characterization of two MHE226-transformed cell lines established from such hemopoietic tumors retrieved from the heart of a 13-day embryo. Cytological analysis indicated a myeloblastic phenotype. These MHE226 cell lines were positive for the MEP17 monoclonal antibody but were negative for the myeloblast-specific 51/2 monoclonal antibody. MHE226 cell lines displayed a doubling time of about 20-24 h and were maintained for at least 1 year. Contrary to E26 myeloblastic cell lines, MHE226 cell lines were independent of chicken myelomonocytic growth factor and could be maintained in serum-free medium. MHE226 cell lines could be induced to differentiate toward the monocytic lineage by retinoic acid. Retinoic acid inhibited proliferation of MHE226 cell lines as early as day 1. After 3 days, MHE226 cells displayed cytological, enzymatic (alpha-naphthyl acetate esterase and chloroacetate esterase), and functional (phagocytosis) characteristics of monocytic cells. The retinoic acid-induced differentiation of MHE226 cells could not be inhibited by v-erbA. Thus, MHE226-transformed cell lines represent a novel model of cell transformation by two nuclear oncoproteins. Furthermore, they provide a model to study molecular mechanisms implicated in the monocytic differentiation program. PMID: 7986751 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 197: Cell Growth Differ. 1994 Aug;5(8):789-99. Inhibition of cell growth by TGF beta 1 is associated with inhibition of B-myb and cyclin A in both BALB/MK and Mv1Lu cells. Satterwhite DJ, Aakre ME, Gorska AE, Moses HL. Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232. The concept of positive and negative regulation of normal cellular growth by diffusible factors is well illustrated by the effects of epidermal growth factor and transforming growth factor beta 1 (TGF beta 1) on mouse keratinocytes (MK) and mink lung epithelial cells (Mv1Lu). MK and Mv1Lu are nontransformed cell lines that reversibly arrest at a point in late G1 in response to TGF beta 1. Previously, we have shown that expression of the protooncogene c-myc is induced upon epidermal growth factor stimulation of quiescent MK and Mv1Lu cells and that transcriptional suppression of c-myc by TGF beta 1 treatment is important in the TGF beta 1 growth inhibition pathway. Using epidermal growth factor-stimulated synchronized MK and Mv1Lu cells, we have investigated the mRNA expression of a large number of growth factor-inducible genes that are critical regulators of growth in G1 and at the G1/S transition. These genes, often found to be dysregulated in cancer, include transcription factors as well as cyclins and their associated kinases, that promote growth, and tumor suppressor genes, that inhibit growth. As reported here, TGF beta 1 significantly inhibited mRNA expression of B-myb and cyclin A in both cell lines, suggesting that these may be important common downstream targets in the growth inhibition pathway. In contrast, the expression patterns of cyclins D1 and D2 and the transcription factors E2F1 and E2F2 were unaffected in MK cells treated with TGF beta 1 but were significantly inhibited in TGF beta 1-treated Mv1Lu cells. We cite the evidence suggesting that the inhibition of B-myb and cyclin A may contribute to the late G1 arrest caused by TGF beta 1 and that these events may be linked through the actions of the product of the retinoblastoma susceptibility gene (Rb) or an Rb family member. PMID: 7986745 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 198: Vet Immunol Immunopathol. 1994 Aug;42(2):185-97. Putative bovine B cell lineage tumor in sporadic bovine leukosis. Ishiguro N, Shinagawa T, Matsui T, Shinagawa M. Department of Veterinary Public Health, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan. Two calves (C924 and C928) clinically identified as suffering from the calf type of sporadic bovine leukosis (SBL) were examined for immunophenotypical distribution of their peripheral blood lymphocytes (PBL) with T cell or B cell specific monoclonal antibodies (mAbs). Flow cytometric profile analysis indicated that both calves possessed a high population of MHC class II positive cells and a low population carrying T cell associated markers. More than 93% of the PBL of C928 were positive for MHC class II and BoCD5, but were not IgM positive, indicating that clonal tumor cells (MHC-II+, BoCD5+ and IgM-) accounted for most of the PBL of C928. A tumor cell line, BLC3, established from calf C924 in nude mice was examined for immunophenotype, DNA rearrangement of immunoglobulin (Ig) genes and expression of cellular oncogenes c-abl, c-myc and c-myb. BLC3 showed a characteristic profile, being MHC class I and MHC class II positive, but without T cell associated markers. Although the rearranged configuration in the Ig loci was not clearly found in Southern blot analysis using sheep Ig probes, steady-state levels of c-myb transcripts were detected in tumor cell line BLC3 by Northern blot hybridization. Taken together, our data show that the calf type of SBL found in these two calves is induced by immature pre-B cells, including tumor cell line BLC3 established in nude mice. PMID: 7975190 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 199: Kobe J Med Sci. 1994 Aug;40(3-4):91-105. A relation between c-myc expression and prognosis of leukemia patients in Indonesia. Haryana SM. Department of Histology, Faculty of Medicine Gadjah Mada University, Yogyakarta, Indonesia. Overexpression of c-myc, c-myb and c-fos proto-oncogene has been observed in many leukemia cells. However, a relation between those oncogene expressions and prognosis of the leukemia is not known in Indonesia. In order to elucidate the relation, expression of those oncogenes in leukemia cells from 52 patients in Indonesia was examined by Northern blot analysis and was compared with prognosis of the disease. The leukemia patients who survived for more than 2 years were 37% of the 52 patients. Many of the samples expressed c-myc mRNA (92%). Although strong expression of c-myb and c-fos mRNA was detected in the samples (c-myb expression in 35% of the leukemia cells and c-fos in 52%), those co-expressions with c-myc mRNA did not alter the prognosis. On the contrary, all of the 4 patients suffering from leukemia which did not express c-myc mRNA survived for more than 2 years. Therefore, c-myc expression in leukemia cells may be used as an indicator for deciding prognosis of the leukemia patients in Indonesia. PMID: 7739203 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 200: Leuk Res. 1994 Aug;18(8):577-85. Interferon-alpha-2b downregulation of oncogenes H-ras, c-raf-2, c-kit, c-myc, c-myb and c-fos in ESKOL, a hairy cell leukemic line, results in temporal perturbation of signal transduction cascade. Harvey WH, Harb OS, Kosak ST, Sheaffer JC, Lowe LR, Heerema NA. Department of Biology, Earlham College, Richmond, IN 47374-4095. ESKOL, a B-lymphoblastoid cell line consisting of late differentiated cells, resembles hairy cell leukemia (HCL). It is pseudodiploid with a deleted 7q and an unbalanced translocation between chromosomes 4 and 6. It was screened by Northern hybridization for oncogenes, including H-ras, c-raf-2 (c-raf1p1), c-kit, c-myc, c-myb, c-fos, Fim-1, c-jun, ski, and c-mos, which are believed to contribute to B-cell differentiation and maturation. Interferon-alpha-2b (IFN) downregulates the expression of H-ras, c-raf-2, c-kit, c-myc, c-myb, c-fos, as determined by Northern hybridization of RNA isolated from cells harvested at time points during a 30 h time course. Downregulation of oncogenes H-ras, c-raf-2, c-kit, whose proteins are associated with cell surfaces or are cytosolar transducers, occurs before those oncogenes c-myc, c-myb, and c-fos, whose products are DNA binding proteins. This suggests a temporal perturbation of signal transduction by IFN. No change in oncogene expression occurred in non-treated cells nor were these oncogenes expressed in the non-transformed B-lymphoblast cell line, Wil-2, under the same treatment regimen. The basis for the IFN perturbation is not understood; yet the role of these oncogenes as signal transducers in differentiation and proliferation of human hematopoietic progenitors is unfolding, and ESKOL is an excellent system in which to study this phenomenon. PMID: 7520517 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 201: Cancer Genet Cytogenet. 1994 Jul 1;75(1):31-9. Characterization of a rearrangement in the c-MYB promoter in the acute lymphoblastic leukemia cell line CCRF-CEM. Jacobs SM, Gorse KM, Kennedy SJ, Westin EH. Department of Microbiology/Immunology, Virginia Commonwealth University/Medical College of Virginia, Richmond. Despite the frequent description of 6q- structural abnormalities in human leukemias and lymphomas, rearrangements of the c-MYB locus have not been detected. We have detected a rearrangement in the c-MYB proto-oncogene in the cell line CCRF-CEM, an immature T-cell leukemia cell line which is not 6q-. Due to this rearrangement, a large portion of the c-MYB promoter conserved between the human and murine c-MYB genes is lost. The rearranged locus, which we have designated MRR (MYB rearranged region), has been cloned and mapped to chromosome 6. Field inversion gel electrophoresis (FIGE) studies reveal that the MRR sequence is linked to the c-MYB locus, suggesting that the rearrangement is due to a submicroscopic deletion. The rearrangement appears to have no effect on c-MYB promoter activity as analyzed in CCRF-CEM cells. The normal locus of the MRR sequence has been cloned from a human placental genomic library. Partial sequence analysis of this clone reveals that a portion of the DNA lost in the rearrangement shows a high degree of homology to a member of the myc family of oncogenes. Thus the characterization of this rearrangement has yielded a new set of probes for the study of chromosome 6q abnormalities in human leukemias and lymphomas and provides the first evidence for potential involvement of the c-MYB locus itself in submicroscopic deletions within chromosome 6. PMID: 8039161 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 202: J Clin Endocrinol Metab. 1994 Jul;79(1):253-7. c-myc, c-fos, and c-myb gene expression in human pituitary adenomas. Woloschak M, Roberts JL, Post K. Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York, New York 10029. The possible roles of certain oncogenes in the development of pituitary tumors has not been investigated. We have examined the expression of c-myc, c-fos, and c-myb in a number of human pituitary tumors by ribonuclease protection assays, as these oncogenes have been implicated to have roles in the pathogenesis of other human tumors (12, 13, 15, 16). In several tumors examined (9 of 30) c-myc was expressed at levels 4-9 times greater than the level detected in normal postmortem pituitary. Although a larger percentage of negative immunohistochemical-staining tumors overexpressed c-myc, c-myc over-expression was not limited to this group of tumors. c-Fos was overexpressed in 1 of 30 tumors examined at a level 5.8-fold higher than that detected in normal postmortem pituitary. This tumor stained positive for ACTH by immunohistochemistry and was considered highly aggressive, demonstrating invasion beyond the sella turcica; however, when other ACTH-staining and invasive pituitary tumors were examined, no abnormality in the expression of c-fos was detected. In 30 tumors, c-myb was expressed at approximately the same level as that detected in normal postmortem pituitary. We conclude that c-myc is overexpressed in a subgroup of pituitary tumors and that this overexpression occurs broadly among the different groups of immunohistochemical-staining tumors. c-Fos overexpression appears to be much less common in pituitary tumors and does not necessarily correlate with the ability of the tumor to become invasive. c-Myb does not appear to have a role in the pathogenesis of pituitary tumors. PMID: 8027238 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 203: Stem Cells. 1994 Jul;12(4):352-69. Differentiation primary response genes and proto-oncogenes as positive and negative regulators of terminal hematopoietic cell differentiation. Liebermann DA, Hoffman B. Fels Institute for Cancer Research and Molecular Biology, Temple University, School of Medicine, Philadelphia, Pennsylvania 19140. By genetically manipulating hematopoietic cells of the myeloid lineage, including both normal cells and differentiation inducible leukemic cell lines, evidence was obtained to indicate that myeloid differentiation primary response (MyD) genes and proto-oncogenes, which are known to control cell growth, function as positive and negative regulators of terminal hematopoietic cell differentiation, which is associated with inhibition of cell growth, and, ultimately programmed cell death (apoptosis). Interferon regulatory factor-1 (IRF-1), an MyD gene induced by Interleukin 6 (IL-6) or Leukemia Inhibitory factor (LIF), plays a role in growth inhibition associated with terminal differentiation. Leucine zipper transcription factors of the fos/jun family, also identified as MyD genes, function as positive regulators of hematopoietic cell differentiation, increasing the propensity of myeloblastic leukemia cells to be induced for differentiation in vitro, and reducing the aggressiveness of their leukemic phenotype in vivo. The zinc finger transcription factor EGR-1, an MyD gene specifically induced upon macrophage differentiation, was shown to be essential for and to restrict differentiation along the macrophage lineage. Finally, evidence has been accumulating to indicate that the novel MyD genes--MyD116, MyD118 and gadd45 (a member in the MyD118 gene family)--play a role in growth arrest and apoptosis of hematopoietic cells, as well as other cell types. The proto-oncogenes c-myc and c-myb, known to regulate cellular growth, were shown to function as negative regulators of terminal differentiation. Both c-myc and c-myb are normally expressed in proliferating myeloblasts and suppressed following induction of differentiation. Deregulated and continuous expression of c-myc was shown to block terminal myeloid differentiation at an intermediate stage in the progression from immature blasts to mature macrophages, whereas deregulated and continuous expression of c-myb blocked the terminal differentiation program at the immature myeloblast stage. By manipulating myc function in conditional (differentiation inducible) mutant myeloblastic leukemia cell lines, expressing a chimeric mycer transgene, it was shown that there is a window during myeloid differentiation, after the addition of the differentiation inducer, when the terminal differentiation program switches from being dependent on c-myc suppression to becoming c-myc suppression independent, and where activation of c-myc has no apparent effect on mature macrophages. These myeloblastic leukemia cell lines provide a powerful tool to increase our understanding of the role of c-myc in normal hematopoiesis and in leukemogenesis, while also providing a strategy to clone myc target genes.(ABSTRACT TRUNCATED AT 250 WORDS) Publication Types: Review PMID: 7951003 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 204: Anticancer Res. 1994 May-Jun;14(3A):1095-6. Early effects of cyclosporin A on in vivo oncogene expression. Ember I, Kiss I, Dezsenyi E, Kertai P. Department of Public Health, University Medical School of Pecs, Hungary. Cyclosporine is a widely used immunosuppressant drug, but development of secondary malignancies has been observed after Cyclosporine containing treatments. In our study we investigated the early effect of Cyclosporin A on oncogene expression. 6, 12, 18 and 24 hours after 80 mg/bwkg Cydosporin A treatment, RNA was isolated from different organs, slot blotted onto Hybond N+ membrane and hybridized with chemiluminescently labelled oncogene probes. As a positive control, rehybridisation with beta-actin probe was used. X-ray films were exposed for 15 minutes, developed, evaluated with densitometer, and the results were expressed as a ratio to the positive control. There was no effect of Cyclosporine A on the expression of c-sis and il-2 receptor genes. The expression of N-ras, c-myc, c-ptc/ret and c-myb oncogenes was elevated in the thymus, lymph nodes, spleen and liver, either transitionally or continuously. We could not detect any elevated gene expressions in the kidney, lung and bone marrow. PMID: 8074456 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 205: Biol Pharm Bull. 1994 May;17(5):586-90. Growth-inhibition by hemin in K562 human leukemic cells is related to hemoglobin-producing activity. Sasaki D, Kosunago S, Mikami T, Matsumoto T, Suzuki M. Department of Microbiology, Tohoku College of Pharmacy, Sendai, Japan. To determine the mechanism of the growth inhibition associated with the induction of erythroid differentiation in K562 cells by hemin, we used two K562 subclones with different hemoglobin (Hb)-producing activity. Hemin strongly inhibited the growth of K562-L, which had a low Hb-producing activity, but not that of K562-H, which had a high Hb-producing activity. When the cell growth of K562-L was inhibited by hemin, the S phase of the cell cycle decreased and the G2/M phase increased. In contrast, hemin had no effect on the cell cycle of K562-H. Without hemin treatment, the alpha-globin mRNA level was related to the degree of Hb production in K562-L and -H but the gamma-globin mRNA level was not. With hemin treatment, there was no increase in the alpha-globin mRNA level in K562-L but there was an increase in K562-H. The difference in alpha-globin mRNA levels correlated with the Hb production in K562-L and -H induced by hemin. The levels of c-myc and c-myb mRNAs in K562-L decreased when cell growth was strongly inhibited by hemin. These findings indicate that the growth inhibition of K562 cells by hemin is due to a suppression of the progression from the G0/G1 phase to the S phase and a delay in the G2/M phase, caused by the inhibition of c-myc and c-myb transcription. It is also affected by the Hb production, reflected in alpha-globin transcription. PMID: 7920413 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 206: Leukemia. 1994 May;8(5):740-8. Signal transduction of steel factor and granulocyte-macrophage colony-stimulating factor: differential regulation of transcription factor and G1 cyclin gene expression, and of proliferation in the human factor-dependent cell line MO7. Hallek M, Ando K, Eder M, Slattery K, Ajchenbaum-Cymbalista F, Griffin JD. Dana-Faber Cancer Institute, Boston, Massachusetts. Steel factor (SF) synergizes with a variety of hemopoietins to support the growth and differentiation of human progenitor cells. The human factor-dependent cell line MO7 has been used as a model to study the interaction of SF with other growth factors such as GM-CSF, because both factors support the proliferation of this cell line and are synergistic in combination. Previous studies have shown that this effect is not readily explained by the synergistic activation of early, cytosolic signal transduction intermediates such as tyrosine kinases, Raf-1, MAP2 kinase, or phospholipase C gamma. In an attempt to further explore the biological and biochemical mechanisms of the synergy between SF and GM-CSF, we examined the effects of these growth factors on the regulation of nuclear proto-oncogenes, cell cycle control genes, and G1-->S transition of MO7 cells. Individually, GM-CSF was a much more potent growth factor for MO7 cells than SF, particularly under serum-free conditions. Only GM-CSF, but not SF, was able to stimulate G1-->S transition of MO7 cells after factor deprivation for 24 h. Northern blot analyses showed also differential effects of GM-CSF and SF on the expression of some nuclear proto-oncogenes and G1 cyclins. GM-CSF (10 ng/ml), but not SF (20 ng/ml) increased the expression of c-myc and cyclin D2 mRNA, whereas both factors caused transient increases of c-fos and cyclin D3 mRNAs. When added simultaneously, GM-CSF and SF induced an at least additive increase of c-fos mRNA expression; this effect required the presence of fetal calf serum. No additive effects of GM-CSF and SF on c-myc, cyclin D2 or D3 mRNA expression were observed. C-jun and c-myb mRNAs were constitutively expressed in the MO7 cell line, but not further increased after stimulation with GM-CSF or SF for 15 min to 48 h. The inability of SF to induce growth promoting genes such as c-myc and cyclin D2 may explain why this cytokine does not support sustained proliferation of MO7 cells. These observations suggest that SF and GM-CSF exert different effects on the expression of genes involved in regulatory pathways of cell proliferation, but the molecular mechanism of synergy remains to be elucidated. PMID: 7514243 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 207: Jpn J Cancer Res. 1994 Apr;85(4):364-71. Proto-oncogene expression in a human chondrosarcoma cell line: HCS-2/8. Zhu JD, Pan HO, Suzuki F, Takigawa M. Chester Beatty Laboratories, London, UK. HCS-2/8 is a stable human chondrosarcoma cell line with many chondrocytic characteristics and has the capacity to form chondrosarcomas in nude mice. The cells display both biochemically and morphologically definable changes in sparse, subconfluent, confluent and over-confluent phases of in vitro culture. Such features of HCS-2/8 cells may reflect the processes of both proliferation and differentiation of chondrocytes in vivo. We examined the correlations of these changes of HCS-2/8 cells with their transcript levels of 21 proto-oncogenes by Northern analysis. We found no detectable transcripts of 9 proto-oncogenes (c-sis, c-met, c-src, c-lyn, c-fgr, c-ros, c-pim, Blym and N-myc), but detected transcripts of 12 other proto-oncogenes (int-2, erbB, c-abl, c-raf-1, c-fyn, K-ras, H-ras, c-mos, c-myc, c-myb, c-fos, and c-jun). In the over-confluent phase, the levels of c-fos and c-raf-1 were increased several dozen times and about 5 times, respectively, while the level of c-abl was about 1/5th of that in the sparse, subconfluent and confluent phases of culture. The level of int-2 increased about 10-fold in the confluent and over-confluent phases of in vitro culture. The transcript levels of c-mos and K-ras were high in the sparse phase, low in the subconfluent and confluent phases and high in the over-confluent phase. The levels of the other 6 proto-oncogenes in HCS-2/8 cells were constant in all phases of in vitro culture. PMID: 8200849 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 208: Mol Cell Biol. 1994 Apr;14(4):2352-60. The novel primary response gene MyD118 and the proto-oncogenes myb, myc, and bcl-2 modulate transforming growth factor beta 1-induced apoptosis of myeloid leukemia cells. Selvakumaran M, Lin HK, Sjin RT, Reed JC, Liebermann DA, Hoffman B. Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104-6059. Cell numbers are regulated by a balance among proliferation, growth arrest, and programmed cell death. A profound example of cell homeostasis, controlled throughout life, is the complex process of blood cell development, yet little is understood about the intracellular mechanisms that regulate blood cell growth arrest and programmed cell death. In this work, using transforming growth factor beta 1 (TGF beta 1)-treated M1 myeloid leukemia cells and genetically engineered M1 cell variants, the regulation of growth arrest and apoptosis was dissected. Blocking of early expression of MyD118, a novel differentiation primary response gene also shown to be a primary response gene induced by TGF beta 1, delayed TGF beta 1-induced apoptosis, demonstrating that MyD118 is a positive modulator of TGF beta 1-mediated cell death. Elevated expression of bcl-2 blocked the TGF beta 1-induced apoptotic pathway but not growth arrest induced by TGF beta 1. Deregulated expression of either c-myc or c-myb inhibited growth arrest and accelerated apoptosis, demonstrating for the first time that c-myb plays a role in regulating apoptosis. In all cases, the apoptotic response was correlated with the level of MyD118 expression. Taken together, these findings demonstrate that the primary response gene MyD118 and the c-myc, c-myb, and bcl-2 proto-oncogenes interact to modulate growth arrest and apoptosis of myeloid cells. PMID: 8139540 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 209: J Virol. 1994 Apr;68(4):2097-107. In vivo cooperation of two nuclear oncogenic proteins, P135gag-myb-ets and p61/63myc, leads to transformation and immortalization of chicken myelomonocytic cells. Adelmant G, Quatannens B, Lagrou C, Wernert N, Torpier G, Saule S, Stehelin D, Laudet V. CNRS UA 1160, Oncologie Moleculaire, Institut Pasteur, Lille, France. To investigate a possible in vivo cooperation between the p61/63myc and P135gag-myb-ets proteins, we used a previously constructed retrovirus, named MHE226, which contains the fused v-myb and v-ets oncogenes of the E26 retrovirus and the v-myc oncogene of MH2. For that purpose, chicken neuroretina cells producing MHE226 and pseudotyped with the Rous associated virus-1 (RAV-1) helper virus were injected in 1-day-old chickens. In control experiments, we also injected chicken neuroretina cells producing E26 (RAV-1), RAV-1 alone, or constructs lacking one of the oncogenes of MHE226. The average life span of MHE226-infected chickens is half that of E26-infected chickens. MHE226-infected chickens harbor tumors scattered in many organs, but compared with E26, MHE226 induced a weak leukemia. Study of integration sites suggests that the majority of the tumors results from clonal or oligoclonal events. Cell cultures were derived from the tumors of MHE226-infected chickens and grown in standard medium without addition of exogenous chicken myelomonocytic growth factor. These cells still divide at high rate after more than 100 passages and can thus be considered immortalized. By using several criteria, these cells were characterized as precursors of the myelomonocytic lineages. PMID: 8138994 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 210: Oncogene. 1994 Apr;9(4):1029-38. Functional aspects of B-Myb in early Xenopus development. Bouwmeester T, van Wijk I, Wedlich D, Pieler T. Otto-Warburg-Laboratorium Max-Planck-Institut fur Molekulare Genetik, Berlin, Germany. The gene encoding Xenopus B-Myb (XB-Myb), a protein structurally related to the nuclear protooncogene product c-Myb, is expressed in early Xenopus embryogenesis. We report on developmental alterations in the nucleocytoplasmic distribution and phosphorylation of XB-Myb in Xenopus oocytes and embryos, as well as on a negative regulatory role of the carboxyl terminus in sequence specific DNA binding. In growing oocytes and early embryonic stages the protein is primarily located in the nucleus; in the full-grown oocyte, however, it remains sequestered in the cytoplasmic compartment. Upon meiotic maturation of the oocyte, XB-Myb becomes hyperphosphorylated. Oocyte/egg isolates of XB-Myb are inhibited in their specific DNA binding activity; truncation of the carboxyl terminal region relieves this block in nucleic acid recognition. Furthermore, we have used overexpression of XB-Myb in Xenopus embryos by means of mRNA injection as an assay for gene function in vivo. Overexpression of full-length XB-Myb, not of the carboxyl terminal deletion mutant, results in an altered morphology of lateral plate mesoderm. PMID: 8134106 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 211: Int J Cancer. 1994 Apr 1;57(1):98-103. Comparison of retinoic acid and phorbol myristate acetate as inducers of monocytic differentiation. Matikainen S, Hurme M. Department of Bacteriology and Immunology, University of Helsinki, Finland. Several human myeloid leukemia cell lines growing in vitro can be induced to differentiate to more mature monocyte/macrophage-like cells by treatment with protein kinase C-activating phorbol esters, such as PMA. In addition to PMA, cells of the THP-1 myeloid leukemia cell line acquire macrophage-like characteristics after treatment with all-trans retinoic acid (RA). To analyze the signal transduction mechanisms induced by RA, we first compared the effects of PMA and RA on the expression of genes which are known to be regulated during monocytic differentiation. Both RA and PMA effectively down-regulated c-myc expression, while c-myb expression decreased only after PMA treatment. Expression of the beta 2-integrin genes, CD11a and CD11b, was clearly increased after both of these treatments. Their effects on the src-family tyrosine kinase genes were different: hck expression was similarly induced by these agents but lyn expression was stronger and more rapid after RA treatment. RA also enhanced lyn mRNA production rapidly in HL-60, indicating that the activation of lyn gene expression is common in monocytic and granulocytic maturation of myeloid leukemia cells. To examine whether the AP-1 enhancer activity is involved in RA-induced monocytic differentiation, THP-1 cells were transiently transfected with a chloramphenicol acetyl transferase (CAT)-reporter gene containing 5 copies of the AP-1 binding sites. In contrast to PMA, RA did not induce any CAT activity in these cells, thus suggesting that the RA-induced changes in the expression of those genes described above were not dependent on the AP-1 enhancer activity. PMID: 7512079 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 212: J Biol Chem. 1994 Mar 25;269(12):8786-91. Early transient suppression of c-myb mRNA levels and induction of differentiation in Friend erythroleukemia cells by the [Ca2+]i-increasing agents cyclopiazonic acid and thapsigargin. Schaefer A, Magocsi M, Stocker U, Kosa F, Marquardt H. Department of Toxicology, Hamburg University Medical School, Federal Republic of Germany. Cyclopiazonic acid and thapsigargin, inhibitors of the endoplasmic reticulum Ca2+ pump were shown to elevate [Ca2+]i in Friend erythroleukemia cells, line F4-6, at concentrations of 1-5 microM and 0.5-2 nM, respectively. At the same concentrations, these agents induced a strong suppression of c-myb mRNA levels within 3 h, whereas c-myc expression remained unaffected. The c-myb expression recovered and approached pretreatment levels at 9-12 h of incubation. The decrease in c-myb mRNA was prevented in Ca(2+)-free medium. Treatment of F4-6 cells with EGTA led to a transient increase in c-myb mRNA with the same kinetics as the Ca2+ pump inhibitor-induced suppression, indicating that c-myb expression is bidirectionally regulated by changes in [Ca2+]i. Studies on the differentiation status of F4-6 cells following cyclopiazonic acid or thapsigargin exposure demonstrated a marked increase in beta-globin mRNA synthesis at 60h and in hemoglobin production at 96 h. These results provide further evidence that a rise in the cytosolic Ca2+ concentration is capable, in Friend erythroleukemia cells, of inducing an early transient suppression of c-myb mRNA levels, which is followed by terminal erythroid differentiation. PMID: 8132611 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 213: Cancer Res. 1994 Mar 15;54(6):1402-6. Correlation between E2F-1 requirement in the S phase and E2F-1 transactivation of cell cycle-related genes in human cells. Sala A, Nicolaides NC, Engelhard A, Bellon T, Lawe DC, Arnold A, Grana X, Giordano A, Calabretta B. Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107. The mammalian nuclear protein E2F-1 has recently been cloned based on its ability to bind the retinoblastoma protein. To determine whether E2F-1 plays a role in the control of the cell proliferation, we introduced an inducible construct expressing an E2F-1 antisense RNA into the human glioblastoma T98G cell line and assessed DNA synthesis during the cell cycle. Expression of the antisense transcripts during the G1-S transition resulted in a marked delay in the completion of DNA synthesis. Band-shift analysis of bacterially produced E2F-1 showed that this protein bound to the promoters of human DNA polymerase-alpha, cyclin D1, and c-myb but not to the cdc2 gene promoter. E2F-1 also transactivated the bound promoters in transient transfection assays. These results suggest a major role for E2F-1 in the control of cell cycle progression via transcriptional regulation of proliferation-associated genes. PMID: 8137237 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 214: Cancer Res. 1994 Jan 15;54(2):592-7. Inhibition by interleukin 4 of leukemia inhibitory factor-, interleukin 6-, and dexamethasone-induced differentiation of mouse myeloid leukemia cells: role of c-myc and junB proto-oncogenes. Kasukabe T, Okabe-Kado J, Hozumi M, Honma Y. Department of Chemotherapy, Saitama Cancer Center Research Institute, Japan. Interleukin 4 (IL-4) inhibited the differentiation of mouse myeloid leukemia M1 cells induced by leukemia inhibitory factor (LIF), interleukin 6, or dexamethasone and conversely enhanced the induction of M1 cell differentiation by 1 alpha,25-dihydroxyvitamin D3. IL-4 blocked LIF-induced differentiation of M1 cells when it was added to the culture medium within 10 h after LIF, but IL-4 did not block differentiation when it was added 12 h after LIF. These results indicate that IL-4 inhibited a critical intermediate step in myeloid leukemia cell differentiation. LIF markedly stimulated the expression of junB mRNA within 2 h but suppressed the expression of c-myb and c-myc after 2- and 12-h treatment, respectively. IL-4 did not significantly affect LIF-induced junB expression or suppression of c-myb expression. However, it interfered significantly with the LIF-induced suppression of c-myc gene expression. Similar results were obtained when interleukin 6 was used to induce differentiation of M1 cells. Dexamethasone and 1 alpha,25-dihydroxyvitamin D3 did not induce junB gene expression but suppressed the expression of c-myb and c-myc. IL-4 also interfered with dexamethasone-induced suppression of c-myc gene expression. On the other hand, IL-4 enhanced 1 alpha,25-dihydroxyvitamin D3-induced down-regulation of c-myc gene expression, consistent with its enhancement of differentiation. These results indicate that the change in c-myc expression induced by IL-4 in M1 cells is closely associated with the effect of IL-4 on the induction of differentiation of M1 cells. PMID: 8275499 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 215: Oncology. 1994 Jan-Feb;51(1):13-7. Amplification of the c-myc proto-oncogene in soft tissue sarcomas. Barrios C, Castresana JS, Ruiz J, Kreicbergs A. Department of Orthopedics, Karolinska Hospital and Institute, Stockholm, Sweden. Soft tissue sarcoma fresh specimens from 23 patients were screened for genetic abnormalities of 3 cellular oncogenes, i.e., c-myc and c-myb and c-Ha-ras. Southern blot hybridization analysis demonstrated amplification of the c-myc gene (4- to 8-fold) in 7 cases, i.e., 3 malignant fibrous histiocytomas, 1 liposarcoma, 1 fibrosarcoma, 1 lymphoma of the soft tissues and 1 synovial sarcoma. Amplification of the c-myc gene was not associated to other genetic alterations such as gene rearrangement. Hybridizations with c-myb and c-Ha-ras probes showed no gene abnormalities in this series. Our results indicate that c-myc oncogene amplification may play an important role in the development of certain soft tissue sarcomas as it has been found for other human malignancies. The clinical significance of these features remains to be established. PMID: 8265096 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 216: Folia Histochem Cytobiol. 1994;32(1):35-40. Oncogene-targeted antisense oligodeoxynucleotides combined with chemotherapy or immunotherapy: a new approach for tumor treatment? Nieborowska-Skorska M, Nakashima M, Ratajczak M, Steplewski Z, Calabretta B, Skorski T. Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107. Synthetic oligodeoxynucleotides (antisenses) complementary to bcr/abl breakpoint junction transcript on Philadelphia chromosome, or c-myb protooncogene inhibit partially the proliferation of Philadelphia positive leukemic cells (antisenses against bcr/abl and c-myb) and other tumor cells (antisenses against c-myb). This phenomenon is accompanied by specific downregulation of mRNA level of the particular gene. To develop a more effective procedure of tumor treatment the combination of low dose of cytostatic and bcr/abl or c-myb antisenses against Philadelphia chromosome positive cell line BV173, and the combination of anti-tumor cytotoxic T lymphocytes (CTL) and c-myb antisenses against melanoma cell line MM-28, were tested in vitro. Our results indicate that the combinations of conventional chemotherapeutic agent and antisense against bcr/abl or c-myb or tumor specific CTL and antisense against c-myb, are highly effective in killing of tumor cells and sparing normal cells. This creates the possibility to develop a more selective and effective treatment of neoplasia. PMID: 8026602 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 217: Z Kardiol. 1994;83 Suppl 4:31-41. [Mechanisms of re-stenosis after angioplasty] [Article in German] Bauriedel G, Kandolf R, Welsch U, Hofling B. Medizinische Klinik I, Klinikum Grosshadern. Restenosis post angioplasty is a segmentally limited, wound healing response to a circumscript traumatization of the vascular wall associated with the therapeutic intervention, which also comprises residual or recoiling plaque components at the time of initial revascularization. Studies with animal models and the analysis of human plaque tissue harvested by autopsy or atherectomy indicate a cascade-like course of this wound healing reaction, in which initially different cell types such as thrombocytes, endothelial cells, monocytes/macrophages and smooth muscle cells (SMCs), later predominantly SMCs are involved. In the first phase of inflammation, angioplasty as a multifactorial stimulus induces a sequence of (a) destruction of endothelial and subendothelial structures, (b) traumatization of medial regions with rupture of the internal elastic lamina, (c) exposition of thrombogenic factors such as collagen or tissue factor, (d) stretching of smooth muscle cells with subsequent expression of proto-oncogens (c-fos, c-myc, c-myb), (e) release of growth factors from cells of the bloodstream, endothelial cells and SMCs by direct traumatization and segmental thrombus formation, and (f) thrombin production with autocatalytic activation of the SMC thrombin receptor. Overlapping the inflammation period, granulation begins 3 days after angioplasty. Proteinases such as plasmin as well as collagenases induce the disintegration of extracellular matrix structures, thereby modulating plaque formation, and lead to an organelle-rich SMC phenotype within the intima and media. The phenotypic alteration of SMCs is considered to be the prerequisite for mitogenic and migratory stimulation. This stage shows different expression patterns of growth factors and their receptors; however, there is only limited knowledge about spatiotemporal and maximal expression as well as their coordination for human vascular wall tissue (PDGF, PDGF-R, EGF-R, FGF, FGF-R, TGF-beta). Overlapping with the granulation period, induction of different components of the extracellular matrix occurs 1-2 weeks after angioplasty, possibly mediated by TGF-beta (phase of matrix formation). Smooth muscle cells produce and secrete matrix proteins such as tenascin, fibronectin, collagens and proteoglycans, and thereby induce a marked increase of the neointimal plaque volume. Angiographic restenoses of coronary and peripheral arteries histologically exhibit tissue with high cellularity (> 500 cells/mm2), associated with SMC activity markers such as PCNA or NMMHC-B. Proliferative and migratory activities of these cells in vitro are augmented by a factor of 2 to 3 as compared to those from chronic primary lesions. Transmission electron microscopic analysis proves that within the media a nearly complete re-differentiation of SMCs occurs, whereas intimal SMCs persist in the intermediate phenotype.(ABSTRACT TRUNCATED AT 400 WORDS) Publication Types: Review Review, Tutorial PMID: 7856278 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 218: Eur J Cancer. 1994;30A(10):1511-6. Comment in: Eur J Cancer. 1994;30A(10):1407-8. Parallel studies of clonogenic leukaemia cells and the leukaemia cell population as a whole in acute myelogenous leukaemia. Preisler HD, Banavali SD, Yin M, Venu G, Li YQ, Gaskins F, Raza A. Rush Cancer Institute, Division of Hematology/Oncology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612. The clonogenic cells in patients with acute myelogenous leukaemia (AML) were evaluated with respect to the relationship between primary and secondary cloning capacity and the proliferative and molecular biological characteristics of the leukaemia cell population as a whole. Secondary cloning capacity was correlated with primary cloning efficiency, and with the ability of the clonogenic cells to produce large sized clones. The cloning capacity of AML cells was unrelated to the cell cycle characteristics of the leukaemia cell population in vivo or to the level of myc, myb, fms, or interleukin (IL)1 beta expression. The sensitivities of the clonogenic cells to cytosine arabinoside and daunorubicin were inversely correlated with the ability of the leukaemia cells to produce large sized clones in vitro. This latter observation may explain the reported relationships between the clonogenic capacity of AML cells and response to chemotherapy. PMID: 7833110 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 219: Cytotechnology. 1994;16(3):167-78. Ras oncogene enhances the production of a recombinant protein regulated by the cytomegalovirus promoter in BHK-21 cells. Yano T, Teruya K, Shirahata S, Watanabe J, Osada K, Tachibana H, Ohashi H, Kim EH, Murakami H. Laboratory of Cellular Regulation Technology, Graduate School of Genetic Resources Technology, Kyushu University, Fukuoka, Japan. In order to enhance recombinant protein productivity in animal cells, we developed the oncogene activated production (OAP) system. The OAP system is based on the premise that oncogenes are able to enhance promoter activity. To this end, we constructed reported plasmids by fusing various promoters to the human interleukin-6 (hIL-6) cDNA, and the effector plasmids by inserting individual oncogenes, for example c-myc, c-fos, v-jun, v-myb and c-Ha-ras, downstream from the human cytomegalovirus immediate early (CMV) promoter. Results of transient expression experiments with BHK-21 cells suggest that the CMV promoter is the most potent promoter examined and that the ras product is able to transactivate the beta-actin, CMV and SR alpha promoters. Recombinant BHK-21 cells producing hIL-6 under the control of the CMV promoter were contransfected with the ras oncogene and dihydrofolate reductase gene, then selected with 50 nM methotrexate to coamplify the ras oncogene. We were able to rapidly establish a stable and highly productive clone which exhibited a 35-times higher production rate as compared to the control value. PMID: 7766145 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 220: Cell Mol Biol Res. 1994;40(5-6):501-11. Regulation of transcription factors c-Myc, Max, and c-Myb by casein kinase II. Bousset K, Oelgeschlager MH, Henriksson M, Schreek S, Burkhardt H, Litchfield DW, Luscher-Firzlaff JM, Luscher B. Institut fur Molekularbiologie, Medizinische Hochschule Hannover, Germany. A number of transcription factors have been shown to be phosphorylated by casein kinase II (CKII). We have identified CKII phosphorylation sites in c-Myc, Max, and c-Myb which are phosphorylated in the cell. Whereas little evidence to any functional significance of the CKII sites in c-Myc has been obtained, phosphorylation of its heterodimeric partner Max alters DNA binding properties. CKII phosphorylation of Ser-2 and -11 in Max resulted in enhanced DNA binding kinetics of both Max/Max homo- and Myc/Max heterodimers without altering steady state binding. Replacing these serine by alanine residues and comparing the wild type with the mutant Max proteins in transactivation assays did not reveal any significant differences. For c-Myb mutational analysis of the CKII phosphorylation sites showed altered steady state DNA binding. Replacing Ser-11/12 by alanine residues resulted in increased DNA binding compared to wt c-Myb or Myb Asp-11/12 as demonstrated by up to 10-fold differences in the dissociation constants. In transactivation assays, the Ala mutant showed consistently an increased activity both on a synthetic and on the mim-1 promoter. A potential CKII phosphorylation site in c-Fos was not phosphorylated in vitro. Analysis with peptides demonstrated that a proline residue at position +1 relative to the acceptor serine was inhibitory. PMID: 7735324 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 221: 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] --------------------------------------------------------------- 222: J Biol Chem. 1993 Sep 25;268(27):20252-8. Impaired erythroid-specific gene expression in cAMP-dependent protein kinase-deficient murine erythroleukemia cells. Pilz RB. Department of Medicine, University of California, San Diego, La Jolla 92093-0652. Murine erythroleukemia cells rendered deficient in cAMP-dependent protein kinase (A-kinase) activity by gene transfection are severely impaired in hexamethylene bisacetamide (HMBA)-induced differentiation (Pilz, R. B., Eigenthaler, M., and Boss, G. R. (1992) J. Biol. Chem. 267, 16161-16167). We now demonstrate that the A-kinase-deficient cells produce hemoglobin normally in response to exogenous hemin and that the heme precursor delta-aminolevulinate (delta-ALA) significantly increases HMBA-induced synthesis of heme and globin chains in these cells; these data suggest that impaired heme synthesis is at least partially responsible for the cells' deficient hemoglobin synthesis. HMBA-induced expression of the erythroid-specific delta-ALA synthetase, porphobilinogen deaminase, and beta-globin mRNAs was less in A-kinase-deficient cells than in parental cells and was reduced in proportion to the cells' residual A-kinase activity; relative transcription rates of these genes were reduced concordantly. Impaired expression of these three erythroid-specific genes was a feature of many independently-derived A-kinase-deficient clones, and normal expression was found in transfectants with normal A-kinase activity. The A-kinase-deficient cells did not exhibit a generalized defect in gene regulation since mRNA expression and transcription rates of H- and L-ferritin, c-myc, c-myb, and several housekeeping enzymes were similar in HMBA-treated parental and A-kinase-deficient cells. Our data suggest that A-kinase may be involved in regulating genes with erythroid-specific promoters and provide further evidence for heme as a regulator of globin chain synthesis. PMID: 8376386 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 223: Radiat Res. 1993 Sep;135(3):394-9. Constitutive overexpression of the c-fos gene in radiation-induced granulocytic leukemia in mice. Ishihara H, Yoshida K, Nemoto K, Tsuneoka K, Shikita M. Division of Chemical Pharmacology, National Institute of Radiological Sciences, Chiba-shi, Japan. Among various myeloid leukemias which were induced by X rays in C3H/He mice (Seki et al., Radiat. Res. 127, 146-149, 1991), the three most frequent types were analyzed for myeloperoxidase, c-myc, c-myb, and c-fos mRNAs. It was shown by in situ hybridization that all the component cells were positive for myeloperoxidase mRNA in granulocytic leukemia, whereas only half the cells were positive in myelomonocytic leukemia and none in monocytic leukemia. Granulocytic leukemia was also characterized by a persistently heightened expression of c-fos, while the other two types of leukemia showed negligibly low expression of the c-fos message. By contrast, both c-myc and c-myb were expressed to a similar extent in all three types of leukemia. When fresh granulocytic leukemia cells were transferred to culture in a medium containing 0.5% fetal calf serum, c-fos mRNA was decreased rapidly during incubation. The decay of c-fos mRNA was inhibited by cycloheximide markedly but was not changed significantly by actinomycin D. In the culture containing 10% fetal calf serum, the rate of decay of c-fos mRNA was slowed down significantly. Addition of dibutyryl cyclic AMP rapidly restored the c-fos expression and kept it elevated for at least 2 h in the cultured granulocytic leukemia cells. Phorbol ester (TPA) and calcium ionophore A23187 also caused a rapid but transient c-fos expression. A transient c-fos expression was inducible by TPA in the other two types of leukemia cells and in the granulocytic leukemia cells. The results suggest that the persistent expression of c-fos is distinguished from its transient expression and is characteristic for granulocytic leukemia cells as it is for normal mature granulocytes. PMID: 8397429 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 224: Acta Pathol Jpn. 1993 Sep;43(9):481-9. Porcine vascular smooth muscle cells immortalized with SV40 ori-defective DNA: characteristics of cell growth and collagen synthesis. Fujimitsu K, Sakata N, Jimi S, Takebayashi S, Sasaguri Y, Morimatsu M. Second Department of Pathology, School of Medicine, Fukuoka University, Japan. A cell line derived from medial smooth muscle cells (SMC) was established from the porcine coronary artery by transfection with ori-defective simian virus 40 plasmid DNA (SV40 DNA). The characteristics of transfected cells (SV40-SMC) such as cell growth, collagen and non-collagen syntheses were investigated. SV40-SMC expressed SV40 large T antigen, c-myc and c-myb encoded proteins in the nuclei. SV40-SMC demonstrated a 'hills and valleys'-like arrangement in overconfluence and actin filaments upon immunofluorescent staining. Under electron microscopic observation, SV40-SMC had larger amounts of synthetic organelles and smaller amounts of filament bundles than those of SMC. SV40-SMC demonstrated three times higher growth activity and 4.4 times greater cellular density than SMC. Smooth muscle cells did not grow in media containing 5% plasma derived serum (PDS) instead of normal serum, whereas SV40-SMC proliferated in this medium. SV40-SMC did not grow in soft agar gel, while HeLa S3 cells, a cell line of human cervical carcinoma, formed colonies in this gel. By immunofluorescent (IF) staining, collagen phenotypes I, III, IV and V were detected in both SV40-SMC and SMC. However, protein synthesis including collagen and non-collagen was higher in SV40-SMC than in the control sample. It was concluded that SV40-SMC were a continuous cell line for vascular SMC regarding morphological characteristics, and demonstrated a higher growth activity, with increased collagen and non-collagen syntheses. This cell line is useful for the investigation of atherogenesis in relation to a proliferation of SMC and an accumulation of extracellular matrices in vascular intima. PMID: 8237368 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 225: C R Acad Sci III. 1993 Aug;316(8):772-9. Transforming growth factor beta 1-mediated growth inhibition in chick embryo fibroblasts: reversion by virally-expressed nuclear oncogenes. Piu F, Jurdic P, Brun G, Samarut J, Castellazzi M. Laboratoire de Biologie Moleculaire et Cellulaire, Ecole Normale Superieure, UMR 49, CNRS, 46, Lyon, France. Transforming growth factor beta 1 (TGF-beta 1) inhibits growth of primary cultures of chick embryo fibroblasts by affecting G1 and strongly increasing the generation time. This inhibition is reversed by the nuclear oncogenes v-jun, v-fos, v-myc, but not v-erbA and v-ets. It is also reversed by v-myb from either avian myeloblastosis virus or avian E26 retrovirus. Taken together, these results strongly suggest that independent, functional interferences may take place between the TGF-beta 1-induced growth inhibitory pathway and the oncogen-driven stimulatory pathway(s) at the level of the AP-1, Myc, and Myb transcription factors. PMID: 8044700 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 226: J Biol Chem. 1993 Jul 5;268(19):14161-7. Functional domains of the human B-myb gene product. Nakagoshi H, Takemoto Y, Ishii S. Laboratory of Molecular Genetics, Tsukuba Life Science Center, Institute of Physical and Chemical Research, (RIKEN), Ibaraki, Japan. Three members of the human myb gene family (c-myb, A-myb, and B-myb) encode transcriptional regulators that can bind to specific DNA sequences. High levels of c-myb expression are usually found in immature hemopoietic cells, but the B-myb is more commonly expressed in many types of cells. To understand the regulation of the activity of B-myb gene product (B-Myb), its functional domains were analyzed. Like c-Myb, B-Myb also has a transcriptional activation domain containing a cluster of acidic amino acids in the region downstream of the DNA-binding domain, which consists of three tandem repeats of 51-52 amino acids. In contrast to c-Myb, B-Myb does not contain a negative regulatory domain. Furthermore, the multiple nuclear localization signals are in at least two regions in the COOH-terminal half of B-Myb, and one of them is adjacent to a potential cdc2 kinase site. These results indicate that B-Myb contains DNA-binding and transcriptional activation domains similar to those of c-Myb, but a regulatory mechanism of B-Myb activity is quite different from that for c-Myb. PMID: 8314782 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 227: 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] --------------------------------------------------------------- 228: Anticancer Res. 1993 Jul-Aug;13(4):1043-7. Modulation of c-myc, c-myb, c-fos, c-sis and c-fms proto-oncogene expression and of CSF-1 transcripts and protein by phorbol diester in human malignant histiocytosis DEL cell line with 5q 35 break point. Gogusev J, Barbey S, Nezelof C. Unite Inserm 90, Hospital Necker-Enfants Malades, Paris, France. Following exposure to phorbol ester (TPA), DEL cell line, a human malignant histiocytosis (MH) cell line, is able to differentiate along a macrophage phenotype and thus it provides a suitable model for analyzing the sequential and differential gene expression associated with monocyte/macrophage differentiation. C-myc, c-myb, c-fos, c-sis and c-fms expression were determined by Northern analysis at various times following TPA treatment. The results showed that TPA down-modulated the constitutive expression of c-myc, c-myb, and c-fms, mRNA to low but still detectable levels. Conversely, TPA-induced differentiation resulted in transient appearance of c-fos, whereas no change in the level of c-sis and actin transcripts were observed. Thus, the c-fms and c-sis genes appear to be regulated in a specific manner in this malignant histiocytosis derived cell line. Furthermore, these investigations demonstrated a constitutive CSF-1 gene expression which transiently increased at mRNA and also at protein level as evaluated by a murine bone marrow CFU bioassay. Through this drug-induced modulation, the DEL cell line offers an additional model for studying some of the subtle interrelations existing between a growth factor (CSF-1) and its receptor (c-fms) in the monocyte/macrophage system. PMID: 8352523 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 229: J Orthop Res. 1993 Jul;11(4):556-63. Amplification of c-myc oncogene and absence of c-Ha-ras point mutation in human bone sarcoma. Barrios C, Castresana JS, Ruiz J, Kreicbergs A. Department of Orthopedics, Karolinska Hospital, Stockholm, Sweden. The genomic organization of four oncogenes, c-myc, c-myb, c-Ha-ras, and v-fms, was analyzed in 21 patients with malignant bone tumors. Amplification of the c-myc proto-oncogene without rearrangement was the sole abnormality detected in four tumors: two chondrosarcomas, one osteosarcoma, and one lymphoma of bone. DNA hybridizations with c-myb, c-Ha-ras, and v-fms probes disclosed no structural gene abnormalities. Point mutations at the 12th codon of the c-Ha-ras gene were investigated with the polymerase chain reaction technique; no alterations were detected. The observed amplification of the c-myc there was not related to histologic type, grade, surgical stage, or ploidy level of the tumors. The results indicated that c-myc amplification, presumed to be involved in the development of malignancy in a variety of solid tumors, is encountered sporadically in malignant bone tumors; however, this occurs without relation to common histopathologic features. The clinical significance of oncogene amplification in bone sarcoma remains to be established. PMID: 8101872 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 230: Behav Neurosci. 1993 Jun;107(3):525-9. Stress-associated modulation of proto-oncogene expression in human peripheral blood leukocytes. Glaser R, Lafuse WP, Bonneau RH, Atkinson C, Kiecolt-Glaser JK. Department of Medical Microbiology and Immunology, Ohio State University Medical Center, Columbus 43210. Changes in the cellular immune response associated with psychological stress were studied by using an academic stress model with medical students. The authors examined the expression of 2 proto-oncogenes, c-myc and c-myb, in peripheral blood leukocytes (PBLs) obtained from medical students at the time of examinations and at a baseline period approximately 1 month prior to the examinations. The level of messenger ribonucleic acid (mRNA) expression of both protooncogenes was significantly lower in PBLs obtained during examinations than in those from the baseline period. In addition, a significant decrease in the level of mRNA to the glucocorticoid receptor and gamma interferon was also found in the same preparations. The decrease in mRNA content of c-myc, c-myb, the glucocorticoid receptor, and gamma interferon in PBLs obtained from subjects during examinations is consistent with data from previous studies using the same model that have demonstrated a down-regulation of T-lymphocyte activation and proliferation in response to mitogens. PMID: 8329139 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 231: J Biol Chem. 1993 May 25;268(15):10876-80. Calcium ionophore-induced transient down-regulation of c-myb mRNA levels in Friend erythroleukemia cells. Schaefer A, Stocker U, Marquardt H. Department of Toxicology, Hamburg University Medical School, Federal Republic of Germany. The effects of calcium ionophores A23187 and ionomycin on the c-myb and c-myc mRNA levels have been investigated in the Friend erythroleukemia cell line F4-6 using Northern blot analysis. Treatment of the cells with 0.5-4 microM A23187 or 1-4 microM ionomycin induced a concentration-dependent decrease in c-myb mRNA; this decrease was abolished by EGTA. c-myc mRNA levels were only moderately affected. After 12-24 h of calcium ionophore exposure, c-myb mRNA returned to pretreatment levels. No similar decrease in c-myb mRNA was seen with the sodium ionophore monensin (up to 16 microM). The dimethyl sulfoxide-induced suppression of c-myb and also of c-myc mRNA levels was not prevented in Ca(2+)-free medium and thus appeared Ca(2+)-independent. A23187 and ionomycin were capable of inducing beta-globin mRNA synthesis in F4-6 cells. Prolonged calcium ionophore exposure, however, strongly reduced cell viability and resulted only in a slight hemoglobin increase at lower concentrations. These results suggest that a rise in [Ca2+]i may be a signal leading to a transient decrease in c-myb mRNA and the initiation of erythroid differentiation in Friend cells. The transient suppression of c-myb mRNA levels represents a common feature of the action of dimethyl sulfoxide and calcium ionophores. PMID: 8496152 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 232: Mol Cell Biol. 1993 May;13(5):2858-69. Mechanism of c-myc regulation by c-Myb in different cell lineages. Cogswell JP, Cogswell PC, Kuehl WM, Cuddihy AM, Bender TM, Engelke U, Marcu KB, Ting JP. Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill 27599-7295. Activation of the murine c-myc promoter by murine c-Myb protein was examined in several cell lines by using a transient expression system in which Myb expression vectors activate the c-myc promoter linked to a chloramphenicol acetyltransferase reporter gene or a genomic beta-globin gene. S1 nuclease protection analyses confirmed that the induction of c-myc by c-Myb was transcriptional and affected both P1 and P2 start sites in a murine T-cell line, EL4, and a myelomonocytic line, WEHI-3. Mutational analyses of the c-myc promoter revealed that two distinct regions could confer Myb responsiveness in two T-cell lines, a distal site upstream of P1 and a proximal site within the first noncoding exon. In contrast, only the proximal site was required for other cell lineages examined. Five separate Myb-binding sites were located in this proximal site and found to be important for c-Myb trans activation. DNA binding was necessary for c-myc activation, as shown by the loss of function associated with mutation of Myb's DNA-binding domain and by trans-dominant repressor activity of the DNA binding, trans-activation-defective mutant. The involvement of additional protein factors was addressed by inhibiting protein synthesis with cycloheximide in a conditional expression system in which the activity of presynthesized Myb was under the control of estrogen. These experiments indicate that de novo synthesis of additional proteins was not necessary for c-myc trans activation. Together these data reveal two cell lineage-dependent pathways by which c-Myb regulates c-myc; however, both pathways are mechanistically indistinguishable in that direct DNA binding by Myb is required for activating c-myc whereas neither de novo protein synthesis nor other labile proteins are necessary. PMID: 8474446 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 233: Br J Cancer. 1993 Apr;67(4):674-9. Uncoupling of growth inhibition and differentiation in dexamethasone-treated human rhabdomyosarcoma cells. De Giovanni C, Lollini PL, Dolcetti R, Landuzzi L, Nicoletti G, D'Andrea E, Scotland K, Nanni P. Istituto di Cancerologia, University of Bologna, Italy. The effects of dexamethasone, a synthetic glucocorticoid, and of N,N-dimethylformamide on in vitro growth and differentiation and on proto-oncogene expression of human rhabdomyosarcoma cells were studied. RD/18 clone cells (derived from the embryonal rhabdomyosarcoma cell line RD) treated with 100 nM dexamethasone showed an almost complete block of differentiation: about 5% myosin-positive cells were observed after 2 weeks of culture in dexamethasone-supplemented differentiation medium, compared to 20% of untreated cultures. Dexamethasone also induced a 20-30% growth inhibition and a more flattened morphology. The treatment with N,N-dimethylformamide induced a significantly increased proportion of myosin-positive cells (reaching about 30%) and a 40% growth inhibition. Induction of differentiation inversely correlated with the levels of c-myc proto-oncogene expression: after a 2 week culture dexamethasone-treated cells showed the highest c-myc expression and N,N-dimethylformamide-treated cells the lowest. Culture conditions per se down-modulated c-erbB1 and up-regulated c-jun expression, with no relationship to the differentiation pattern. Other proto-oncogenes were not expressed (c-sis, N-myc, c-mos, c-myb) or were not modulated (c-fos, c-raf). Therefore dexamethasone and N,N-dimethylformamide, both causing a decreased growth rate, showed opposing actions on myogenic differentiation and on c-myc proto-oncogene expression of human rhabdomyosarcoma cells. PMID: 8471424 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 234: Curr Probl Cancer. 1993 Mar-Apr;17(2):69-141. Small cell lung cancer: etiology, biology, clinical features, staging, and treatment. Cook RM, Miller YE, Bunn PA Jr. Department of Medicine, University of Colorado Health Sciences Center, Denver. Lung cancer is the leading cause of cancer death in the United States. Small cell lung cancer (SCLC) accounts for 20% to 25% of all bronchogenic carcinoma and is associated with the poorest 5-year survival of all histologic types. SCLC differs in its etiologic, pathologic, biologic, and clinical features from non-SCLC, and these differences have translated to distinct approaches to its prevention and treatment. Compared with other histologic types of lung cancer, exposures to tobacco smoke, ionizing radiation, and chloromethyl ethers pose a substantially greater risk for development of SCLC. The histologic classification of SCLC has been revised to include three categories: (1) small cell carcinoma, (2) mixed small cell/large cell, and (3) combined small cell carcinoma. Ultrastructurally, SCLC displays a number of neuroendocrine features in common with pulmonary neuroendocrine cells, including dense core vesicles or neurosecretory granules. These dense core vesicles are associated with a variety of secretory products, cell surface antigens, and enzymes. The biology of SCLC is complex. The activation of a number of dominant proto-oncogenes and the inactivation of tumor suppressor genes in SCLC have been described. Dominant proto-oncogenes that have been found to be amplified or overexpressed in SCLC include the myc family, c-myb, c-kit, c-jun, and c-src. Altered expression of two tumor suppressor genes in SCLC, p53 and the retinoblastoma gene product, has been demonstrated. Cytogenetic and molecular evidence for chromosomal loss of 3p, 5q, 9p, 11p, 13q, and 17p in SCLC has intensified the search for other tumor suppressor genes with potential import in this malignancy. Bombesin/gastrin-releasing peptide, insulin-like growth factor I, and transferrin have been identified as autocrine growth factors in SCLC, with a number of other peptides under active investigation. Several mechanisms of drug resistance in SCLC have been described, including gene amplification, the recently described overexpression of multi-drug resistance-related protein (MRP), and the expression of P-glycoprotein. The classic SCLC staging system has been supplanted by a revised TNM staging system where limited disease and extensive disease are equivalent to the TNM stages I through III and stage IV, respectively. Therapeutically, recent strategies have attained small improvements in survival but significant reductions in the toxicities of chemotherapeutic regimens. Presently, the overall 5-year survival for SCLC is 5% to 10%, with limited disease associated with a significantly higher survival rate.(ABSTRACT TRUNCATED AT 400 WORDS) Publication Types: Review Review, Tutorial PMID: 8395998 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 235: In Vitro Cell Dev Biol. 1993 Mar;29A(3 Pt 1):239-48. Characterization of the DiFi rectal carcinoma cell line derived from a familial adenomatous polyposis patient. Olive M, Untawale S, Coffey RJ, Siciliano MJ, Wildrick DM, Fritsche H, Pathak S, Cherry LM, Blick M, Lointier P, et al. University of Texas M. D. Anderson Cancer Center, Section of Gastrointestinal Oncology and Digestive Diseases, Houston 77030. The DiFi human colorectal cancer cell line was recently established from a familial adenomatous polyposis patient with extracolonic features characteristic of the Gardner syndrome. These cells have now been propagated for 150 passages in standard culture media and vessels without feeder layers or collagen coatings. They retain features of colonic epithelial cells such as surface microvilli, secretory vesicles, and desmosomes. Cytosol of DiFi cells contains a high level (502 U/mg protein) of the mucin CA 19-9. In addition, DiFi cells produce carcinoembryonic antigen, and induce tumors in athymic mice. Cytoskeleton analysis of DiFi cells by fluorescence microscopy showed a pronounced disorganization of actin cable structure. The isozyme genetic signature of DiFi cells is unique (0.01 probability of finding the same genetic signature in a different cell line), differs from that of HeLa cells, and has expressional features seen in other colorectal cell lines. The DiFi cell karyotype is tetraploid, contains many marker chromosomes, and shows numerous episomal particles. Two copies of chromosome 18 were absent, and only a single normal chromosome 17 was found. This parallels detection of allelic losses from DiFi cell DNA at loci on chromosomes 17p and 18 using molecular (cDNA) probes. DiFi cells clearly express transcripts for the c-myc proto-oncogene, the c-myb proto-oncogene, and the p53 tumor suppressor gene. Transforming growth factor beta inhibits DiFi cell growth in soft agar and suppresses c-myc expression in these cells. The value of this cell line in the study of genetic alterations in colorectal cancer is discussed. PMID: 8385096 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 236: Blood. 1993 Feb 15;81(4):935-41. Erratum in: Blood 1993 Jun 1;81(11):3168. Shaw H [corrected to Ralph H]. Erythropoietin-specific cell cycle progression in erythroid subclones of the interleukin-3-dependent cell line 32D. Shimada Y, Migliaccio G, Ralph H, Migliaccio AR. Laboratory of Hematopoietic Growth Factors, Lindsley F. Kimball Research Institute, New York Blood Center, New York 10021. Recently, a variety of growth factor-dependent subclones of the murine interleukin-3 (IL-3)-dependent cell line 32D have been isolated. These subclones include those dependent for growth on erythropoietin (Epo) (32D Epo), granulocyte-macrophage colony-stimulating factor (GM-CSF) (32D GM), or granulocyte colony-stimulating factor (G-CSF) (32D G). 32D Epo1.1 is a revertant of 32D Epo and is capable of growing in IL-3. These cell lines express the differentiation program appropriate to the specific growth factor and depend on the growth factors not only for proliferation but also for survival. To determine how the signal for proliferation is triggered by various growth factors, we examined the DNA histograms and the expression of cell cycle-specific genes in the different cell lines. The cell cycle-specific genes analyzed were myc (early G1), myb (late G1), and the structural genes for the calcium-binding protein 2A9 (middle G1) and histone H3 (G1-S boundary). The DNA histogram analysis of cells in the logarithmic phase of growth showed that approximately 40% of 32D, 32D GM, 32D G, and 32D Epo1.1 (growing in IL-3) were cells with a 2N DNA content (and therefore in G0/G1), and another 40% have a DNA content intermediate between 2N and 4N (in S phase). In contrast, 32D Epo and 32D Epo1.1 (growing in Epo) had fewer cells in the G0/G1 phase of the cell cycle compared with the number of cells that were in the S phase (19% to 31% v 69% to 78%, respectively). Because all the cell lines have comparable doubling times (15 to 18 hours), the cell distribution among the phases of the cell cycle is proportional to the length of the phase. Therefore, cells growing in IL-3 (32D and 32D Epo1.1), GM-CSF (32D GM), or G-CSF (32D G) progress along the cycle in a manner typical of previously reported nontransformed cell lines. In contrast, cells growing in Epo (32D Epo or 32D Epo1.1) spend relatively less time in G0/G1 and correspondingly more time in S. These data were confirmed by the analysis of the tritiated thymidine (3H-TdR) suicide rate and of the expression of cell cycle-specific genes. The 32D and 32D Epo1.1 cells growing in IL-3 had a suicide rate of congruent to 50%, whereas the suicide rate of 32D Epo and 32D Epo1.1 growing in Epo was higher than 75%.(ABSTRACT TRUNCATED AT 400 WORDS) PMID: 7679009 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 237: Virology. 1993 Feb;192(2):578-86. v-erbA cooperates with bFGF in neuroretina cell transformation. Garrido C, Li RP, Samarut J, Gospodarowicz D, Saule S. Cancer Research Institute, University of California, San Francisco 94143-0128. We have studied the transforming ability of the oncogenes erbA and/or erbB in chicken neuroretina (CNR) cells and the effect of basic fibroblast growth factor (bFGF) on the transformed phenotype. The erbA oncogene alone was only transforming in the presence of bFGF. In contrast, cells expressing erbB as well as erbA + erbB were transformed in a bFGF-independent manner and were unresponsive to the growth factor. We studied whether other oncogenes could also block the cooperation between erbA and bFGF. Cytoplasmic or membrane-bound oncogenes (src, ras, or mill raf) increased the transforming potential of erbA but rendered the cells unresponsive to bFGF. Conversely, the nuclear oncogenes tested (fos and myb-ets + myc) also cooperated with erbA in CNR cell transformation but the cells remained responsive to the growth factor. A likely explanation is that CNR cells carrying the cytoplasmic but not the nuclear oncogenes have already activated the bFGF signal transduction pathway. PMID: 7678474 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 238: Nucleic Acids Res. 1993 Jan 25;21(2):267-72. Transcription regulation by murine B-myb is distinct from that by c-myb. Watson RJ, Robinson C, Lam EW. Ludwig Institute for Cancer Research, St Mary's Hospital Medical School, London, UK. The transcription regulatory properties of murine B-myb protein were compared to those of c-myb. Whereas c-Myb trans-activated an SV40 early promoter containing multiple copies of an upstream c-Myb DNA-binding site (MBS-1), and similarly the human c-myc promoter, B-Myb was unable to do so. Full-length B-Myb translated in vitro did not bind MBS-1; however, truncation of the B-Myb C-terminus or fusion of the B-Myb DNA-binding domain to the c-Myb C-terminus showed that it was inherently competent to interact with this motif. Further evidence from co-transfection experiments, demonstrating that B-Myb inhibited trans-activation by c-Myb, suggested that failure of B-Myb to trans-activate these promoters did not simply occur through lack of binding to MBS-1. Moreover, using GAL4/B-Myb fusions, it was found that an acidic region of B-Myb, which by comparison to c-Myb was expected to contain a transcription activation domain, actually had no inherent trans-activation activity and indeed appeared to trans-inhibit c-Myb. In contrast to the above findings, both B-Myb and c-Myb were able to weakly trans-activate the DNA polymerase alpha promoter. Results obtained here demonstrate that the activities of B-Myb and c-Myb are clearly distinct and suggest that these related proteins may have different functions in regulation of target gene expression. PMID: 8382794 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 239: Eur J Biochem. 1993 Jan 15;211(1-2):7-18. Erratum in: Eur J Biochem 1993 Aug 1;215(3):907. The Ets family of transcription factors. Wasylyk B, Hahn SL, Giovane A. CNRS-LGME/INSERM-U. 184, Institut de Chimie Biologique, Faculte de Medecine, Strasbourg, France. Interest in the Ets proteins has grown enormously over the last decade. The v-ets oncogene was originally discovered as part of a fusion protein expressed by a transforming retrovirus (avian E26), and later shown to be transduced from a cellular gene. About 30 related proteins have now been found in species ranging from flies to humans, that resemble the vEts protein in the so-called 'ets domain'. The ets domain has been shown to be a DNA-binding domain, that specifically interacts with sequences containing the common core trinucleotide GGA. Furthermore, it is involved in protein-protein interactions with co-factors that help determine its biological activity. Many of the Ets-related proteins have been shown to be transcription activators, like other nuclear oncoproteins and anti-oncoproteins (Jun, Fos, Myb, Myc, Rel, p53, etc.). However, Ets-like proteins may have other functions, such as in DNA replication and a general role in transcription activation. Ets proteins have been implicated in regulation of gene expression during a variety of biological processes, including growth control, transformation, T-cell activation, and developmental programs in many organisms. Signals regulating cell growth are transmitted from outside the cell to the nucleus by growth factors and their receptors. G-proteins, kinases and transcription factors. We will discuss how several Ets-related proteins fit into this scheme, and how their activity is regulated both post- and pre-translationally. Loss of normal control is often associated with conversion to an oncoprotein. vEts has been shown to have different properties from its progenitor, which might explain how it has become oncogenic. Oncogene-related products have been implicated in the control of various developmental processes. Evidence is accumulating for a role for Ets family members in Drosophila development, Xenopus oocyte maturation, lymphocyte differentiation, and viral infectious cycles. An ultimate hope in studying transformation by oncoproteins is to understand how cells become cancerous in humans, which would lead to more effective treatments. vEts induces erythroblastosis in chicken. Cellular Ets-family proteins can be activated by proviral insertion in mice and, most interestingly, by chromosome translocation in humans. We are at the beginning of understanding the multiple facets of regulation of Ets activity. Future work on the Ets family promises to provide important insights into both normal control of growth and differentiation, and deregulation in illness. Publication Types: Review PMID: 8425553 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 240: Proc Natl Acad Sci U S A. 1993 Jan 15;90(2):477-81. Induction of protein-tyrosine-phosphatase activity by interleukin 6 in M1 myeloblastic cells and analysis of possible counteractions by the BCR-ABL oncogene. Zafriri D, Argaman M, Canaani E, Kimchi A. Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel. Interleukin 6 (IL-6) induces in M1 myeloblastic cells growth arrest and terminal differentiation toward monocytes. It is reported here that IL-6 reduced by 5- to 20-fold the tyrosine phosphorylation of cellular proteins in these cells. The same-fold reduction was also observed in M1 cells that were transfected with the BCR-ABL deregulated protein kinase. In these stable clones, the levels of tyrosine phosphorylation of cellular proteins were 30- to 100-fold higher than in the parental cells. IL-6 did not reduce the expression levels or the inherent tyrosine kinase activity of BCR-ABL p210. By measuring the protein-tyrosine-phosphatase (PTPase; protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48) activity in crude cell lysates, we found that protein dephosphorylation resulted, at least partially, from induction of PTPase activity by IL-6. The induction of PTPase in the BCR-ABL-transfected clones was not sufficient to confer the minimal protein phosphorylation levels characteristic of IL-6-treated cells. Yet, the transfected M1 clones showed normal growth and differentiation responses to IL-6. None of the gene responses to IL-6 including suppression in the levels of c-myc, c-myb, and cyclin A mRNA; junB and c-jun mRNA induction; and dephosphorylation of retinoblastoma protein were rescued by the BCR-ABL oncogene. The functional relevance of PTPase induction by IL-6 is discussed. PMID: 8421678 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 241: Anticancer Res. 1993 Jan-Feb;13(1):113-8. Chromosomal changes and correspondingly altered proto-oncogene expression in human gliomas. Value of combined cytogenetic and molecular genetic analysis. Patt S, Thiel G, Maas S, Lozanova T, Prosenc N, Cervos-Navarro J, Witkowski R, Blumenstock M. Institute of Neuropathology, Free University of Berlin, Germany. A combined cytogenetic and molecular genetic study was performed to analyze seven primary brain tumors: one oligoastrocytoma WHO-grade II, one anaplastic astrocytoma grade III, one anaplastic astrocytoma grade III/IV and four glioblastomas by G-banding and RNA dot blotting. A normal karyotype was found in the oligoastrocytoma. One of the two anaplastic astrocytomas (male) contained cells with a normal karyotype and cells with a Y-chromosomal loss, and the other one showed structural abnormalities too complex for complete analysis in mostly polyploid cells. Two of the four glioblastomas had few and the other two multiple chromosomal changes such as +7, +20, -8, -9 del(9)(p21), -10, del(10)(q24), -13,14, del(17)(p21), -22, add(3)(q13), double minutes and marker chromosomes. Compared to normal brain, all tumors had an increased EGFr and both anaplastic astrocytomas as well as three glioblastomas a decreased H-ras expression. The two glioblastomas with multiple chromosomal changes showed increased EGFr, Ki-ras, myb, mos and myc, decreased H-ras and N-ras and unchanged levels of abl, src and sis. Both the cytogenetic and molecular genetic findings are compatible even in the case of chromosomal losses, where the genes on the remaining allele may be responsible for dominant gene regulation mechanisms which result in a protooncogene overexpression. Our findings indicate that, apart from proto-oncogene overexpression, other mechanisms, e.g. tumor suppressor gene inactivation, are important for glial tumorigenesis. Karyotypic analysis makes it possible to search specifically for genetic events still unknown but arising from particular chromosomal changes. PMID: 8476201 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 242: Autoimmunity. 1993;16(3):167-71. Expression of c-myc, c-myb, and c-sis in fibroblasts from affected and unaffected skin of patients with systemic sclerosis. Feghali CA, Boulware DW, Ferriss JA, Levy LS. Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana 70112. We examined c-sis, c-myc, and c-myb proto-oncogene expression in fibroblasts cultured from affected and unaffected skin of patients with systemic sclerosis (SSc), and from healthy donor skin. Total cellular RNA from cultured dermal fibroblasts was used in slot blot analysis and scanning densitometry or phosphorimaging to quantify steady-state levels of proto-oncogene mRNAs. PDGF B-chain levels in culture supernatants of fibroblasts were determined by ELISA. Our results demonstrate that steady-state levels of c-myc and c-myb mRNA were elevated 1.5- to 5.6-fold in intralesional fibroblasts from SSc patients as compared to other cells examined. Levels of c-sis mRNA and PDGF-B protein were comparable regardless of source. Elevated c-myc and c-myb expression may be indicative of, and may contribute to, fibroblast activation in SSc. PMID: 8003611 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 243: Cytotechnology. 1993;11(2):121-31. Purification and characterization of interferon-like antiviral protein derived from flatfish (Paralichthys olivaceus) lymphocytes immortalized by oncogenes. Tamai T, Shirahata S, Sato N, Kimura S, Nonaka M, Murakami H. Taiyo Central R&D Institute, Taiyo Fishery Co. Ltd. Ibaraki, Japan. Flatfish leukocytes were transfected with the expression plasmids of the v-myc, c-myc, c-fos, v-myb and c-Ha-ras oncogenes. Only cotransfection of c-Ha-ras with c-myc or c-fos resulted in complete immortalization of the cells. Interferon-like anti-viral protein was found in the cultured medium of the immortalized lymphocytes. The protein was purified by DEAE-Toyopearl 650 M ion exchange chromatography and WGA agarose affinity chromatography. The protein was a glycoprotein of about 16 kDa. The antiviral activity of the protein was trypsin-sensitive and was fairly stable at pH values from 4 to 8. The protein retained about 60% of the activity even at 60 degrees C and showed a broad antiviral activity for various fish cells and viruses. PMID: 7686026 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 244: Ann N Y Acad Sci. 1992 Dec 26;673:110-9. The response of human lymphocytes to phytohemagglutinin is impaired at different levels during aging. Pieri C, Recchioni R, Moroni F, Marcheselli F, Damjanovich S. Department of Gerontological Research, Italian National Research Centers on Aging I.N.R.C.A., Ancona. Several parameters generally believed to be necessary for the activation and progression of proliferation of human lymphocytes have been investigated and compared with special reference to aging. The responding capacity of plasma membrane potential to depolarizing and also repolarizing conditions induced by exposure to mitogens like PHA was lower in lymphocytes from old donors as compared to those of young ones. This indicates a significant age-dependent difference in the readiness to respond to channel-activating perturbations. As an early signal of activation, after one hour PHA stimulation the merocyanine 540 uptake by the lipid regions was chosen, based on the property of this fluorescent probe to bind to loosely packed lipids of the plasma membrane. The proteins encoded by the c-myc and c-myb genes were chosen as markers of the G0/G1 and G1/S phased transition, respectively. The mean number of cells that increased the uptake of MC 540 following mitogenic stimulation did not differ in young vs. old individuals. However, 4 samples out of 10 from the old population showed lower MC 540 fluorescence than the lowest signal from the young population. The number of responding cells was decreased during aging when the presence of the c-myc protein was taken as its measure; and this decrease was further accentuated, determining the expression of the c-myb protein. This frequently encountered age-dependent pattern, however, was not followed by the lymphocytes of all old donors. One example is reported in which the MC 540 uptake, the c-myc and c-myb expression in the cells from one old subject fell in the range of the young subjects. However, even in this case, the response of the lymphocytes as measured by 3H-thymidine incorporation was only 64% of that of young subjects. For this sample, we found an impairment of the response at the mitochondrial level. In addition to these parameters, the amount of 3H-thymidine incorporated by the cells expressing the c-myb protein was calculated. The values in old individuals were lower than those in the young, suggesting that not all the cells expressing the c-myb protein were able to synthesize DNA in lymphocyte populations from the elderly. Our data support the view that the age-dependent decline of lymphocyte responsiveness to mitogens can be accounted for by impairments at different levels.(ABSTRACT TRUNCATED AT 400 WORDS) Publication Types: Review Review, Tutorial PMID: 1485708 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 245: Acta Med Okayama. 1992 Dec;46(6):407-15. Detection of oncogene rearrangements in human non-Hodgkin's lymphomas. Kondo E, Yoshino T, Akagi T, Hayashi K, Takahashi K. Second Department of Pathology, Okayama University Medical School, Japan. Southern blot hybridization was used to detect the rearrangement and amplification of five proto-oncogenes (bcl-2, bcl-1, c-myc, c-myb and c-Ha-ras) and one tumor suppressor gene (RB-1) in 55 Japanese patients with non-Hodgkin's lymphoma; 16 with T-cell lymphomas and 39 with B-cell lymphomas (7 follicular and 32 diffuse lymphomas). Genetic abnormalities of the proto-oncogenes were detected in 7 of the 55 (13%). Genetic abnormalities of bcl-2 plus other genes were detected in 5 of 7 cases of follicular lymphoma (71%), rearrangements of bcl-2 and c-myc, rearrangement of bcl-2 and amplification of c-myb. Genetic abnormalities were observed in only three cases of diffuse lymphoma. In each of 3 cases of B-cell lymphoma, one of the genes, blc-2 mbr, bcl-2 mcr and c-myc, was rearranged respectively. The incidence of genetic abnormalities in diffuse lymphomas (6.3%) was lower than that in follicular lymphomas. None of diffuse lymphomas had double oncogene abnormality. No abnormalities were found in RB-1, bcl-1, and Ha-ras. These findings suggest that follicular lymphomas are associated with some abnormalities of oncogenes not restricted to bcl-2 that facilitate growth which may be associated with their clinical features. PMID: 1485535 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 246: Diagn Mol Pathol. 1992 Dec;1(4):235-8. Amplification of the c-myc proto-oncogene in human chondrosarcoma. Castresana JS, Barrios C, Gomez L, Kreicbergs A. Department of Tumor Pathology, Karolinska Hospital, Stockholm, Sweden. The genomic organization of four oncogenes, i.e., c-myc, c-myb, c-Ha-ras, and c-fms, was investigated in fresh surgical specimens from 10 patients with cartilaginous tumors. Among nine chondrosarcomas, six were primary lesions and three local recurrences. The remaining case was a chondroblastoma. Amplification of the c-myc proto-oncogene was the sole abnormality detected in this series, occurring in two chondrosarcomas (four- and eight-fold). No other genetic alteration such as oncogene rearrangement was found. Nor was there any amplification of the other oncogenes studied. Both c-myc-amplified tumors were primary lesions and histologically classified as grade II; according to flow DNA cytometry, one was diploid and the other aneuploid. In our limited series, there was no overall relationship between c-myc amplification, on the one hand, and histologic subtype, malignancy grade, surgical stage, or ploidy level, on the other. Our study shows that amplification of the c-myc oncogene, presumed to be involved in the development of malignancy, is encountered in occasional human chondrosarcomas, however, without any relationship to other well-known features of this tumor entity. The clinical significance of this gene amplification remains to be established. PMID: 1342971 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 247: Oncogene. 1992 Dec;7(12):2529-34. Physical mapping of human loci homologous to the chicken nov proto-oncogene. Martinerie C, Viegas-Pequignot E, Guenard I, Dutrillaux B, Nguyen VC, Bernheim A, Perbal B. Laboratoire d'Oncologie Virale et Moleculaire, Institut Curie, Orsay, France. The human locus (novH) corresponding to the nov protooncogene overexpressed in avian nephroblastoma has been identified and mapped on chromosome 8q24.1. Another locus sharing homology with novH and corresponding to the connective tissue growth factor (CTGF) gene has also been mapped on chromosome 6q23.1. The chromosomal assignment of nov and CTGF proximal to c-myc and c-myb respectively is of interest because chromosomal abnormalities involving these regions have been associated with different human tumors including Wilms'. PMID: 1334251 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 248: Ann N Y Acad Sci. 1992 Oct 28;660:64-9. Inhibition of cell cycle progression by antisense oligodeoxynucleotides. Baserga R, Reiss K, Alder H, Pietrzkowski Z, Surmacz E. Jefferson Cancer Institute, Jefferson Medical College, Philadelphia, Pennsylvania 19107-5541. We have used the antisense strategy to study the role of certain genes in cell cycle progression. In particular, we used antisense oligodeoxynucleotides to study: (1) the role of the IGF-1 receptor in the control of cell proliferation; and (2) the sequence of gene expression during the cell cycle. Our results can be summarized as follows: (1) the activation of the IGF-1 receptor by its ligand, IGF-1, is an obligatory step in the proliferation of fibroblasts and hemopoietic cells; and (2) the expression of DNA synthesis genes, such as PCNA, DNA polymerase alpha, and cdc2, is dependent on the expression of previous genes. A tentative temporal order is: c-myc > c-myb > IGF-1 receptor > DNA synthesis genes. PMID: 1340157 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 249: J Biol Chem. 1992 Oct 25;267(30):21300-2. Activation of two discrete signaling pathways by erythropoietin. Patel HR, Choi HS, Sytkowski AJ. New England Deaconess Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215. Erythropoietin stimulation of erythroid cells induces a rapid increase in c-myc and decrease in c-myb mRNA levels. The signal pathway to c-myc requires activation of protein kinase C. We now report that erythropoietin down-regulates expression of c-myb via a discrete, serine/threonine-specific phosphatase-dependent pathway. The protein kinase C-blocker H7 completely prevents the c-myc response to erythropoietin, but has no effect on the c-myb response. In contrast, the phosphatase blocker okadaic acid prevents the c-myb response but not the c-myc response. This effect of okadaic acid on the c-myb response is concentration-dependent. Both the protein kinase C-dependent signal to c-myc and the phosphatase-dependent signal to c-myb regulate gene expression by a transcriptional arrest mechanism operative within the first intron of the respective protooncogenes. In contrast, the chemical inducer of differentiation, dimethyl sulfoxide, regulates expression of c-myc and c-myb without activation of these phosphatase- and kinase-dependent pathways. PMID: 1328229 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 250: Blood. 1992 Oct 15;80(8):1880-4. Nitric oxide modulation of human leukemia cell differentiation and gene expression. Magrinat G, Mason SN, Shami PJ, Weinberg JB. Division of Hematology-Oncology, VA Medical Center, Durham, NC. Nitric oxide (NO) functions as an intercellular messenger molecule in such varied contexts as neurotransmission, immune regulation, and the control of vascular tone. We report that NO, delivered as purified gas or released from the pharmacologic NO donors sodium nitroprusside or 6-morpholino-sydnonimine, caused monocytic differentiation of cells of the human myeloid leukemia cell line HL-60 and altered gene expression. The treated cells stopped proliferating, became spread and vacuolated, had increased expression of nonspecific esterase and the monocyte marker CD14, and displayed increased capacity to produce hydrogen peroxide. Furthermore, these treated cells had increased steady-state expression of messenger RNA (mRNA) for tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta), but decreased expression of mRNA for the proto-oncogenes c-myc and c-myb. The increase in TNF-alpha and IL-1 beta mRNA levels was due (at least in part) to a new transcription of these specific mRNAs. NO elaborated in the bone marrow microenvironment may have a role in normal and malignant hematopoietic cell growth and differentiation. PMID: 1382708 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 251: J Cell Physiol. 1992 Oct;153(1):147-56. Regulation of cell proliferation: late down-regulation of c-myb preceding myelo-monocytic cell differentiation. Yen A, Samuel V, Forbes M. Department of Pathology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853. Expression of the c-myb nuclear oncogene during the cell proliferation and differentiation of HL-60 human promyelocytic leukemia cells was characterized and compared to the expression of c-fos, another nuclear oncogene with transcriptional regulatory activity. During progression through the cell cycle, the amount of c-myb protein increased. The increase was commensurate with total cell size, thus preserving the relative abundance of c-myb protein present at the onset of the cell cycle. In HL-60 cells, the induced metabolic cascade leading to terminal myeloid or monocytic differentiation segregates into two steps occurring over two division cycles. Expression of c-myb did not diverge from the control until late in this metabolic cascade when it declined prior to onset of terminal differentiation. This course of expression was similar for both the retinoic acid induced myeloid or the 1,25-dihydroxy vitamin D2 induced monocytic terminal differentiation of the cells. Bromodeoxyuridine, which induces proliferative arrest but not phenotypic differentiation of these cells, induced the same course of c-myb expression as the inducers of terminal differentiation. The same course of c-myb expression with growth arrest induced by these three different means is consistent with a potential proliferation regulatory role for c-myb in late but not early events leading to terminal differentiation. The dynamics of c-myb expression during this process were qualitatively, but not quantitatively, similar to the course of c-fos expression. Thus, taken with previous results, then amongst the nuclear oncogenes or tumor suppressor genes, c-myc, RB, c-fos, and c-myb, only c-myc and RB expression exhibit early regulation during induced HL-60 cell differentiation. PMID: 1522128 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 252: 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] --------------------------------------------------------------- 253: 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] --------------------------------------------------------------- 254: Leuk Res. 1992 Oct;16(10):1003-11. c-myc and c-myb expression in acute myelogenous leukemia. Gopal V, Hulette B, Li YQ, Kuvelkar R, Raza A, Larson R, Goldberg J, Tricot G, Bennett J, Preisler H. University of Cincinnati Medical Center, Ohio 45267-0508. Monoclonal antibodies and flow cytometry were used to detect the expression of c-myc and c-myb in the bone marrow (BM) and peripheral blood (PB) cells of patients with acute myelogenous leukemia (AML). The expression of neither gene was correlated with the percent blast cells in the BM or PB nor was there a correlation between c-myc and c-myb expression. A wide range of expression of each gene was found within each FAB type of AML. Patients who had a high proportion of leukemia cells expressing c-myb were less likely to respond to remission induction therapy than patients in whom a low proportion of cells expressed c-myb. This association appears to reflect an inverse relationship between the proportion of cells expressing c-myb and the sensitivity of leukemia cells to the killing effects of chemotherapy in vivo. Treatment outcome was unrelated to c-myc expression. PMID: 1405703 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 255: Cancer Res. 1992 Oct 1;52(19):5178-82. Establishment of the human BSMZ breast cancer cell line, which overexpresses the erbB-2 and c-myc genes. Watanabe M, Tanaka H, Kamada M, Okano JH, Takahashi H, Uchida K, Iwamura A, Zeniya M, Ohno T. Department of Microbiology, Jikei University School of Medicine, Tokyo, Japan. A new cell line, designated BSMZ, was established from a malignant pleural effusion from a woman with breast cancer. This line has a doubling time of 27 h and has now been cultured for over 120 passages. The large, rounded BSMZ cells grow as both a monolayer and as aggregations in suspension. Intracytoplasmic lumen, a finding consistent with results from cells derived from mammary tissue, was detected on ultrastructural analysis. Injection of BSMZ cells into nude mice resulted in the growth of solid tumors 4 weeks after inoculation. The solid tumor was identical to the original BSMZ cells in microscopic and electron microscopic studies. These cells possess an average of 80 chromosomes. Expression of erbB-2 and c-myc genes was increased by 10-fold, while there was no detectable overexpression of the N-ras and c-myb genes. Southern analysis has revealed amplification of the erbB-2 and c-myc loci. The BSMZ cell line may therefore provide a useful model for the study of human breast cancer and overexpression of the erbB-2 gene. PMID: 1356615 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 256: Oncogene. 1992 Sep;7(9):1817-25. Multiple mechanisms of regulation of the human c-myb gene during myelomonocytic differentiation. Boise LH, Gorse KM, Westin EH. Department of Pharmacology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298. Alterations in expression of c-myb can have profound effects on the growth and differentiation of hematopoietic cells. Thus, it is important to understand the mechanisms by which c-myb is regulated during hematopoietic cell differentiation. Previous studies pertaining to the regulation of c-myb have been carried out with the avian and murine forms of the gene; the current studies were designed to determine the mechanisms of regulation of the human form of c-myb. Transcriptional analysis by nuclear run-on assays revealed that an attenuation of transcription was the means of primary regulation during retinoic acid- and vitamin D3-induced differentiation of HL-60 cells, while other mechanisms in addition to attenuation were active during dimethyl sulfoxide (DMSO)- and phorbol ester-induced differentiation. Densitometric analysis of the changes in c-myb transcription caused by phorbol ester suggested that the c-myb promoter may be down-regulated during phorbol ester-induced differentiation of HL-60. Additional studies exhibited post-transcriptional regulation by phorbol ester. DMSO was also shown to regulate c-myb at the post-transcriptional level. Interestingly, the post-transcriptional regulation of c-myb by DMSO required continuous transcription. This requirement was shared for c-myc but not ornithine decarboxylase expression. The transcriptional dependency of c-myb post-transcriptional regulation did not equate to translational dependency, thus a novel post-transcriptional regulatory mechanism may control c-myb gene expression. The multiple levels of regulation of c-myb suggest the importance of proper control for hematopoietic cell differentiation. PMID: 1323820 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 257: Virology. 1992 Aug;189(2):583-91. Monoclonal antibodies recognizing normal and retrovirus-transformed chicken hematopoietic cells. Liu JL, Klein PA, Moscovici MG, Moscovici C. Department of Pathology and Laboratory Medicine, School of Medicine, University of Florida, Gainesville 32610. The avian hematopoietic system has long been an invaluable model to study the mechanisms of cell growth and differentiation. We have developed six MAbs against either chicken embryonic hematopoietic precursor cells or retrovirus-transformed cells. MAbs Mo1, Mo2, and Mo3 recognized transformation-associated markers expressed in AMV-transformed nonproducer cell line-BM2. Not only were these markers expressed 7 to 10 folds higher on BM2 than on normal monocytic cells, but their expression was drastically reduced when BM2 cells were induced to differentiate into macrophages by PMA. The control of marker expression is associated with v-myb-transforming cascade, since another monocytic lineage-specific oncogene, v-myc, did not enhance the expression of these markers. MAb Em1 detected a marker that is normally present in 20% of the cells from the 30/50% interface of a discontinuous percoll gradient of normal 4-day-embryo yolk sac. Its expression is also found in AEV-transformed cells and MSB1 cells. The epitope for Em1 was exposed after neuraminidase treatment on erythroleukemia cell line 6C2, which suggested that sialylation and/or glycosylation is pivotal in regulating the expression of specific markers in differentiation pathways during embryogenesis and tumorigenesis. MAb Em2 recognized proliferating hematopoietic cells after the fourth day of embryogenesis. MAb Em3, on the other hand, is presumed to be specific for an oncofetal antigen expressed in various transformed cells but only in 10% of the cells from 30/50% interface of a discontinuous percoll gradient of normal 4-day-embryo yolk sac. These MAbs will be useful for dissecting the expression of differentiation markers within normal versus abnormal differentiation pathways in molecular terms. PMID: 1641980 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 258: Leukemia. 1992 Aug;6(8):828-33. Induction of differentiation in Friend-erythroleukemia cells by aclacinomycin A: early transient decrease in c-myc and c-myb mRNA levels. Schaefer A, Dressel A, Lingelbach K, Schmidt CA, Steinheider G, Marquardt H. Department of Toxicology, University of Hamburg Medical School, Germany. Chemical inducers of the differentiation are known to cause an early transient decrease in c-myc and c-myb mRNA levels in Friend erythroleukemia cells preceding the down-regulation of c-myc and c-myb expression in the course of irreversible terminal differentiation. We therefore investigated the early effect of the potent differentiation-inducing anthracycline antitumor antibiotic, aclacinomycin A, on the c-myc and c-myb mRNA levels in the Friend cell line, F4-6, using Northern blot analysis. Aclacinomycin A induced a rapid decrease in the levels of c-myc and c-myb transcripts within 0.5-1 h and 2-3 h, respectively. The time course of decline in c-myc and c-myb expression was similar to that observed with dimethylsulfoxide or after transcription blockage brought about by a high concentration of actinomycin D. By 12 to 18 h after aclacinomycin A exposure, the c-myc and c-myb mRNA levels had returned to about pretreatment levels. When the cells were treated with adriamycin, an anthracycline that reduces cell proliferation in F4-6 cells without increasing differentiation, an early decrease in c-myc and c-myb expression was not observed. These results suggest that the transient decrease in c-myc and c-myb mRNA levels in F4-6 cells may be an early differentiation-related biochemical effect of aclacinomycin A. PMID: 1640736 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 259: Oncogene. 1992 Aug;7(8):1667-70. Tumorigenic effects mediated in the avian embryo by one or more oncogenes associated with v-myc. al Moustafa AE, Quatannens B, Dieterlen-Lievre F, Saule S. Institut d'Embryologie cellulaire et moleculaire du CNRS, Nogent Marne, France. We have previously shown that introduction of the v-myc oncogene in chick or quail embryos at E3 induces rapidly growing heart rhabdomyomas. We now report that a retrovirus containing one or two other oncogenes induces additional pathologies specified by the v-myc-associated oncogene. The v-mil/myc combination introduced at E3 induces, in addition to heart rhabdomyomas, tumors of proliferating cells aggregated onto the luminal aspect of vessels in both chick and quail embryos. In the quail these cells react positively with the quail-specific mAb QH1, which recognizes endothelial and most hemopoietic cells, while chick intravascular cells do not react with the chick-specific mAb VIA2 that recognizes hemopoietic cells. Thus the v-mil/myc tumors appear to be of endothelial origin. The v-myb-ets/myc combination injected at E3 induces cardiorhabdomyomas and aggressive VIA2-positive hemopoietic tumors in chick embryos, but only the v-myc-induced cardiorhabdomyomas in quail embryos. When injected into hatched animals, v-myc alone transforms hemopoietic and perhaps endothelial cells, but not cardiac cells. Thus the developmental stage at which a cell type can be transformed by v-myc and another associated oncogene depends on as yet undefined species-specific factors. More importantly, several examples of oncogene cooperation in vivo are adduced by these experiments. The type of cell transformed is specified by the viral oncogene combination. PMID: 1630827 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 260: J Leukoc Biol. 1992 Aug;52(2):173-82. Effects of glucocorticoids on the TPA-induced monocytic differentiation. Hoff T, Spencker T, Emmendoerffer A, Goppelt-Struebe M. Institute of Molecular Pharmacology, Medical School Hannover, Germany. The human monocytic cell line U937 was used as a model system to investigate the effects of glucocorticoids on monocytic differentiation. Upon incubation with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) (5 x 10(-9) M) for 48 to 72 h, the immature U937 cells ceased to proliferate and became morphologically and functionally macrophage-like. Preincubation of the cells with glucocorticoids (dexamethasone and prednisolone, 10(-7) and 10(-6) M) but not progesterone (10(-6) M) had marked effects: The cells remained in suspension and developed very little cell-cell interaction. This correlated with decreased expression of the surface molecules ICAM-1 and CD18 as determined by fluorescence-activated cell sorter analysis. The TPA-induced ability of the cells to release lysozyme or to generate reactive oxygen radicals (determined as reduction of nitroblue tetrazolium) was markedly reduced. The induction of cyclooxygenase activity and thus the ability to release prostanoids was almost completely abolished. Inhibition of prostanoid synthesis was also observed when the glucocorticoids were administered 24 or 48 h after TPA. The primary step of TPA induction, the activation and translocation of protein kinase C, however, was not affected by glucocorticoids as determined by activity measurements and Western blot analysis. There was no change in the subsequent TPA-induced induction of c-fos. The down-regulation of the differentiation-related oncogenes c-myc and c-myb was the same in cells treated with TPA in the presence or absence of glucocorticoids. Furthermore, no significant effect of glucocorticoids on the TPA-induced growth arrest was observed. Glucocorticoids thus interfere with TPA-induced functions, which are typical for activated macrophages; however, they do not impair the differentiation process and concomitant growth inhibition. PMID: 1506773 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 261: J Cell Biol. 1992 Aug;118(4):775-84. Mitosis-specific phosphorylation of the nuclear oncoproteins Myc and Myb. Luscher B, Eisenman RN. Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104. The c-myc and c-myb proto-oncogenes encode phosphorylated nuclear DNA binding proteins that are likely to be involved in transcriptional regulation. Here we demonstrate that both Myc and Myb proteins are hyperphosphorylated during mitosis. In the case of Myb, hyperphosphorylation is accompanied by the appearance of three M phase-specific tryptic phosphopeptides. At least one of these phosphopeptides corresponds to a phosphopeptide generated after phosphorylation of Myb in vitro by p34cdc2 kinase. By contrast, the mitotic hyperphosphorylation of Myc does not correlate with the appearance of unique phosphopeptides, suggesting that M phase and interphase sites may be clustered within the same peptides. In addition Myc does not appear to be a target for p34cdc2 phosphorylation. The hyperphosphorylated forms of Myc and Myb from mitotic cells are functionally distinct from the corresponding interphase proteins in that the former have reduced ability to bind nonspecificially to double-stranded DNA cellulose. Furthermore, mitotic Myb binds poorly to oligodeoxynucleotides containing an Myb response element. We surmise that the decreased DNA binding capacity of hyperphosphorylated Myb and Myc during M phase may function to release these proteins from chromatin during chromosome condensation. PMID: 1500422 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 262: Biochem Biophys Res Commun. 1992 Jul 31;186(2):715-22. Transactivation of the human c-myc gene by c-Myb. Zobel A, Kalkbrenner F, Vorbrueggen G, Moelling K. Max-Planck-Institut fuer Molekulare Genetik, Abt. Schuster, Germany. We analyse the contribution of six Myb-binding sites in the upstream c-myc sequences to transactivation by co-transfection assays. Surprisingly, deletion of the six Myb-binding sites did not influence the transactivation of c-myc by c-Myb protein. Instead, the strongest transactivation was observed with a c-myc reporter plasmid which contains only 450 bp of exon 1 including the c-myc promoter P2. An exchange of the DNA binding domain of c-Myb by that of GAL4 led only to small transactivation effects indicating that the DNA binding domain of c-Myb is essential for transactivation of the c-myc gene. These results suggest either an indirect transactivation mechanism of the c-myc gene by c-Myb proteins or a role of the DNA binding domain for additional effects than DNA binding. PMID: 1497659 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 263: Blood. 1992 Jul 15;80(2):412-9. Erythropoietin-induced stimulation of differentiation and proliferation in J2E cells is not mimicked by chemical induction. Busfield SJ, Klinken SP. Department of Biochemistry, University of Western Australia, Nedlands. The J2E cell line is a novel erythroid cell line that differentiates in response to erythropoietin (Epo), the physiologic stimulus for erythropoiesis. After exposure to Epo, the cells synthesize hemoglobin, and we show here that this process is tightly linked to increases in cellular proliferation and DNA synthesis. The hormone-induced terminal differentiation also results in morphologic alterations and the accumulation of transcripts for alpha, beta maj, and beta min globins. c-myc messenger RNA levels increase rapidly after exposure to Epo and precede the increase in cell division, while c-myb undergoes a transient decrease. Differentiation of J2E cells can also be achieved with sodium butyrate, but, in contrast with Epo, this is associated with a retardation of replication and a sudden decrease in c-myc levels. These results show that, in this system, chemically induced differentiation differs from terminal maturation promoted by Epo and that the processes of proliferation and differentiation in J2E cells can be uncoupled. PMID: 1627799 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 264: J Immunol. 1992 Jul 1;149(1):17-23. Expression of the murine homologue of the cell cycle control protein p34cdc2 in T lymphocytes. Kim YH, Proust JJ, Buchholz MJ, Chrest FJ, Nordin AA. Clinical Immunology Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224. The mammalian homologue of the cdc2 gene of the fission yeast Schizosaccharomyces pombe encodes a p34cdc2 cyclin-dependent kinase that regulates the cell cycle of a wide variety of cell types. Resting murine T lymphocytes contained no detectable p34cdc2 protein, histone kinase activity, or specific mRNA for the cdc2 gene. Activation of the T cells by immobilized anti-CD3 resulted in the expression of specific mRNA late in the G1 phase of the cell cycle, and p34cdc2 protein was detectable at or near G1/S. At this point in the cell cycle, the protein was phosphorylated at tyrosine and displayed no H1 histone kinase activity. As the cells progressed through the cycle, the amount of specific mRNA and p34cdc2 increased, and H1 histone kinase activity was detectable when the cells were blocked at G2/M by nocodazole. The activation of T cells by phorbol dibutyrate induced the expression of IL-2R but failed to induce the synthesis of IL-2 or the expression of cdc2-specific mRNA. Under these conditions, the activated cells failed to enter the S phase of the cell cycle. Because the presence of IL-2 added exogenously during activation by phorbol dibutyrate resulted in the expression of cdc2-specific mRNA and progression through the cell cycle, either IL-2 or the interaction with IL-2R may be involved in the expression of cdc2 and regulation of the G1/S transition. PMID: 1637418 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 265: J Immunol. 1992 Jul 1;149(1):300-8. Independent regulation of c-myc, B-myb, and c-myb gene expression by inducers and inhibitors of proliferation in human B lymphocytes. Golay J, Cusmano G, Introna M. Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy. Although a detailed picture is emerging about the nature of the second messengers involved in B cell activation and proliferation, little is yet known about the intracellular events taking place further downstream. The c-myb proto-oncogene, the structurally related B-myb gene, and c-myc probably code for transcription factors, have been demonstrated to be necessary for the proliferation of hemopoietic cells, and their expression is indeed induced after mitogenic stimulation of T and B lymphocytes. They are therefore likely to be key elements in the regulation of gene expression during proliferation. We have set out to study the regulation of the expression of these two myb genes and of that of c-myc in relation to entry into the different phases of the cell cycle during mitogenic stimulation of resting human B lymphocytes. Resting tonsillar B cells stimulated with the anti-CD20 antibody 1F5 alone are induced to enter the G1 but not the S phase of the cell cycle, whereas co-stimulation with the anti-CD40 antibody G28.5 further drives them to enter the S phase and proliferate. The G28.5 antibody alone has been reported to partially activate and increase the alertness of resting B cells without inducing them to enter G1. In this report we show that increasing the strength of the activating signal leads to progressive induction of the proliferation-related genes studied. Thus the G28.5 antibody alone induces c-myc mRNA only in resting B cells, 1F5 induces both c-myc and B-myb, and the full mitogenic signal given by both antibodies together is accompanied by increased expression of all three--c-myc, B-myb, and c-myb genes. In addition, using a semi-quantitative polymerase chain reaction method, we show that different inhibitors of B cell proliferation, namely, cyclosporin A, an anti-CD19 antibody (HD37), and transforming growth factor beta 1 (TGF-beta 1), inhibit differentially the induction of these same genes after mitogenic stimulation of B cells. Whereas cyclosporin A inhibits induction of all three genes, TGF-beta 1 specifically blocks B-myb induction and CD19 has little effect on either of the genes tested. We conclude that c-myb, B-myb, and c-myc are regulated independently from one another, that induction of c-myc and B-myb together is not sufficient to trigger B cell proliferation, and we suggest that expression of all three is a prerequisite for proliferation to occur. PMID: 1376749 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 266: J Virol. 1992 Jul;66(7):4191-200. Induction of differentiation-associated changes in established human cells by infection with adeno-associated virus type 2. Klein-Bauernschmitt P, zur Hausen H, Schlehofer JR. Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Heidelberg, Germany. The nonpathogenic human defective parvovirus adeno-associated virus (AAV) type 2 induced differentiation-associated antigens in cells of the human leukemia cell line HL60 (CD 67), as well as in two different lines of immortalized human keratinocytes, HaCaT and HPK Ia cells (involucrin and cytokeratin 10). Simultaneously, expression of the c-myc and c-myb oncogenes and the retinoblastoma gene was down regulated whereas c-fos expression increased in infected cells. These data point to the potential of AAV to induce functions related to the differentiation pathway in different types of human cells. This phenomenon may be involved in the reported oncosuppressive properties of AAV infections. PMID: 1318400 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 267: Blood. 1992 Jun 15;79(12):3337-43. Inhibition of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) messenger RNA (mRNA) expression in HL-60 leukemia cells by pentoxifylline and dexamethasone: dissociation of acivicin-induced TNF-alpha and IL-1 beta mRNA expression from acivicin-induced monocytoid differentiation. Weinberg JB, Mason SN, Wortham TS. VA Center, Department of Medicine, Durham, NC 27705. We have previously noted that the glutamine antagonist acivicin (alpha S,5S-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid) induces monocytoid differentiation of freshly isolated human myeloid leukemia cells and cells of the myeloid leukemia cell line HL-60, and that the differentiation is accompanied by increases in expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta). Because we also showed that TNF-alpha and IL-1 beta can act synergistically to cause monocytoid differentiation of HL-60 cells, we hypothesized that acivicin-induced TNF-alpha and IL-1 beta, in an autocrine manner, caused the differentiation. The purpose of the present study was to determine the causal roles of TNF-alpha and IL-1 beta in the acivicin-induced differentiation of HL-60 cells by the use of dexamethasone (DEX) and pentoxifylline (PTX), two drugs that effectively inhibit expression of TNF-alpha and IL-1 beta. Acivicin caused a monocytoid differentiation of the cells as manifest by diminished cell growth, morphologic maturation of the cells, increased ability to generate hydrogen peroxide in response to acute treatment with phorbol myristate acetate, and increased expression of nonspecific esterase and the surface antigens CD14 and CD11b. Acivicin treatment also caused the cells to have diminished steady-state expression of messenger RNA (mRNA) for c-myc and c-myb, and increased expression of mRNA for TNF-alpha and IL-1 beta. DEX and PTX did not alter cell growth, and did not block the acivicin-induced block in growth. PTX caused a slight increase in nonspecific esterase expression, but DEX had no effect on this, and neither drug diminished the acivicin-induced increase in nonspecific esterase. Although neither drug alone lessened the acivicin enhancement of hydrogen peroxide production, DEX and PTX together reduced this. DEX did not modify the acivicin-induced morphologic maturation of the cells, but PTX alone or PTX with DEX potentiated the acivicin-induced increase in mature cells. Basal CD14 and CD11b expression were slightly reduced by DEX and PTX, but neither drug modified the acivicin-induced increases. DEX and PTX reduced the acivicin-induced increases in TNF-alpha and IL-1 beta mRNA expression, but they had little or no effect on the acivicin-induced decreases in expression of mRNA for c-myc and c-myb. Thus, DEX and PTX effectively block the acivicin-induced expression of TNF-alpha and IL-1 beta, but they have little influence on the acivicin-induced differentiation process.(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 1596574 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 268: Mech Ageing Dev. 1992 Jun;64(1-2):177-87. Phytohemagglutinin induced changes of membrane lipid packing, c-myc and c-myb encoded protein expression in human lymphocytes during aging. Pieri C, Recchioni R, Moroni F, Marcheselli F, Lipponi G. Gerontological Research Department, I.N.R.C.A., Ancona, Italy. Three parameters which signal different stages of cell activation were analyzed in lymphocytes from young and old subjects. Merocyanine 540 (MC-540) incorporation into the membrane lipid phase was used as a very early marker of activation and was measured after 1 h of phytohemagglutinin (PHA) stimulation. The proteins coded by c-myc and c-myb protooncogenes were determined by appropriate antibodies and were taken as markers of the G0/G1 and G1/S phase transition, respectively. The number of cells which increased the uptake of MC-540 following PHA stimulation did not differ when comparing young and old individuals. Both the number of the responding cells and the size of the response were decreased during aging when the presence of the c-myc protein was taken into account. A consistent decrease of the percentage of lymphocytes able to express the c-myb protein was observed in the cells from old donors as compared to those from the young ones, but the amount of detectable protein per cell remained unchanged. Our data suggest that the deficiency of responsiveness which accompanies aging is due to impairments at different points of the cell cycle. The very low number of cells expressing the c-myb protein is likely the result of step by step elimination of those cells not able to fulfill the requirements to progress along the cell cycle. PMID: 1630155 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 269: Oncogene. 1992 Jun;7(6):1233-40. Transcriptional activation of the c-myc gene by the c-myb and B-myb gene products. Nakagoshi H, Kanei-Ishii C, Sawazaki T, Mizuguchi G, Ishii S. Laboratory of Molecular Genetics, Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan. To identify the target genes modulated by the myb gene product (Myb), a co-transfection assay with a Myb expression plasmid was performed. Both c-Myb and B-Myb, another member of the myb gene family, trans-activated the human c-myc promoter. DNAase I footprint analysis using the bacterially expressed c-Myb, identified multiple c-Myb binding sites in the c-myc promoter region. Deletion analysis of the c-myc promoter suggested that some number of Myb binding sites, not a specific Myb binding site, is important for the c-Myb-induced trans-activation of the c-myc promoter. Using the c-myc-chloramphenicol acetyltransferase (CAT) construct as a reporter in a co-transfection assay, the domains of c-Myb required for trans-activation were examined. The functional domains of c-Myb identified using the c-myc promoter were almost the same as those identified previously with the artificial target gene containing Myb binding sites, but unlike the case with the artificial target gene the N-terminal half of the previously identified negative regulatory domains and the C-terminal 136 amino acids were required for the maximal trans-activation of the c-myc promoter. These results indicate that there are some differences in the regulation of Myb-dependent trans-activation in different target genes. PMID: 1594249 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 270: Mol Cell Biol. 1992 Jun;12(6):2493-500. Deregulated c-myb disrupts interleukin-6- or leukemia inhibitory factor-induced myeloid differentiation prior to c-myc: role in leukemogenesis. Selvakumaran M, Liebermann DA, Hoffman-Liebermann B. Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104-6059. The c-myb proto-oncogene is abundantly expressed in tissues of hematopoietic origin, and changes in endogenous c-myb genes have been implicated in both human and murine hematopoietic tumors. c-myb encodes a DNA-binding protein capable of trans-activating the c-myc promoter. Suppression of both of these proto-oncogenes was shown to occur upon induction of terminal differentiation but not upon induction of growth inhibition in myeloid leukemia cells. Myeloblastic leukemia M1 cells that can be induced for terminal differentiation with the physiological hematopoietic inducers interleukin-6 and leukemia inhibitory factor were genetically manipulated to constitutively express a c-myb transgene. By using immediate-early to late genetic and morphological markers, it was shown that continuous expression of c-myb disrupts the genetic program of myeloid differentiation at a very early stage, which precedes the block previously shown to be exerted by deregulated c-myc, thereby indicating that the c-myb block is not mediated via deregulation of c-myc. Enforced c-myb expression also prevents the loss in leukemogenicity of M1 cells normally induced by interleukin-6 or leukemia inhibitory factor. Any changes which have taken place, including induction of myeloid differentiation primary response genes, eventually are reversed. Also, it was shown that suppression of c-myb, essential for terminal differentiation, is not intrinsic to growth inhibition. Taken together, these findings show that c-myb plays a key regulatory role in myeloid differentiation and substantiate the notion that deregulated expression of c-myb can play an important role in leukemogenicity. PMID: 1588953 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 271: Eur J Immunol. 1992 Jun;22(6):1391-6. Interleukin-1 induces protein tyrosine phosphorylation in T cells. Munoz E, Zubiaga A, Huang C, Huber BT. Department of Pathology, Tufts Medical School, Boston. Interleukin (IL)-1 alpha activates multiple signal transmission pathways in the T helper type 2 cell line, D10A, and these pathways are linked to two separate IL-1 receptors (IL-1R). In the present report we show that IL-1 induces the activation of tyrosine kinase in these cells, leading to tyrosine phosphorylation of a subset of proteins of 38, 75, 97 and 115 kDa. This type of phosphorylation is prevented by a monoclonal antibody directed against the 80-kDa IL-1R and by tyrphostins which are specific inhibitors of tyrosine kinases. In addition, this inhibitor blocks IL-1-and IL-2-induced proliferation in D10A cells as well as the c-myc and c-myb proto-oncogene mRNA expression in response to IL-1. Interestingly, the inhibitor of cAMP-dependent kinase, H-8, only blocks IL-1-induced c-myb, but not c-myc mRNA expression. Altogether, our results demonstrate that the activation of a tyrosine kinase(s) is an early and major event that happens after IL-1/IL-1R interaction, leading to an increase in intracellular cAMP which results in c-myb and IL-5 mRNA expression. Independent of cAMP, by tyrosine phosphorylation of specific substrates IL-1 also induces c-myc and IL-6 mRNA expression and cellular proliferation. PMID: 1376256 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 272: Blood. 1992 Jun 1;79(11):2841-8. A diverged homeobox gene is involved in the proliferation and lineage commitment of human hematopoietic progenitors and highly expressed in acute myelogenous leukemia. Deguchi Y, Kirschenbaum A, Kehrl JH. Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892. HB24 is a diverged homeobox gene known to be expressed in hematopoietic progenitor cells. We show here that the inhibition of HB24 expression in CD34+ bone marrow cells via antisense (AS) oligonucleotides impaired the proliferation of these cells in response to interleukin-3 and granulocyte-macrophage colony-stimulating factor. The treatment of CD34+ cells with HB24 AS oligonucleotides also reduced the levels of c-fos, c-myc, c-myb, cyclin B, and p34cdc2 messenger RNAs compared with cells treated with control oligonucleotides. Conversely, the transient transfection of HB24 into a subpopulation of CD34 cells inhibited their differentiation into mature hematopoietic cell types. In addition, HB24 messenger RNA transcripts were elevated in bone marrow and peripheral blood mononuclear cells isolated from patients with acute myelogenous leukemia compared with normal controls. These data suggest that HB24 is an important transcription factor during hematopoietic progenitor proliferation and that differentiation to specific cell types requires its downregulation. Furthermore, dysregulated expression of HB24 impairs the normal differentiation of hematopoietic progenitors and may contribute to leukemogenesis. PMID: 1375114 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 273: J Cell Physiol. 1992 Jun;151(3):539-48. Inhibition by 1,25 dihydroxyvitamin D3 of c-myc down-regulation and DNA fragmentation in cytosine arabinoside-induced erythroid differentiation of K562 cells. Moore DC, Carter DL, Studzinski GP. Department of Laboratory Medicine and Pathology, UMD-New Jersey Medical School, Newark 07103. The effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on DNA fragmentation, altered expression of the heat shock protein (hsp) 70 gene, and protooncogenes c-myc and c-myb was studied during chemical induction of erythroid differentiation in K562 cells. Preincubation of K562 cells with 1,25(OH)2D3 did not alter the concentration of hemoglobin in cells which did differentiate, but led to a reduction in the accumulation of low molecular weight DNA generated by Ara-C administration. The extent of this reduction was similar to the degree of inhibition of hemoglobin formation in the culture as the whole. Preincubation with 1,25(OH)2D3 had no effect on the increase of hsp 70 gene expression induced by a 48-hr treatment with Ara-C, but prevented the Ara-C-induced down-regulation of the protooncogene c-myc. The protooncogene c-myb was down-regulated after 15 min of treatment with Ara-C, and exposure to 1,25(OH)2D3 prior to Ara-C caused a further down-regulation of its expression. The data suggest that the events associated with erythroid differentiation may be separable into at least two groups; one of these may have an influence on the kinetics of the cell cycle traverse, and the other may be related to the expression of the erythroid phenotype. PMID: 1295901 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 274: Genes Dev. 1992 May;6(5):864-75. Functional analysis of the transcriptional activator encoded by the maize B gene: evidence for a direct functional interaction between two classes of regulatory proteins. Goff SA, Cone KC, Chandler VL. Department of Biology, University of Oregon, Eugene 97403. The B, R, C1, and Pl genes regulating the maize anthocyanin pigment biosynthetic pathway encode tissue-specific transcriptional activators. B and R are functionally duplicate genes that encode proteins with the basic-helix-loop-helix (b-HLH) motif found in Myc proteins. C1 and Pl encode functionally duplicate proteins with homology to the DNA-binding domain of Myb proteins. A member of the b-HLH family (B or R) and a member of the myb family (C1 or Pl) are both required for anthocyanin pigmentation. Transient assays in maize and yeast were used to analyze the functional domains of the B protein and its interaction with C1. The results of these studies demonstrate that the b-HLH domain of B and most of its carboxyl terminus can be deleted with only a partial loss of B-protein function. In contrast, relatively small deletions within the B amino-terminal-coding sequence resulted in no trans-activation. Analysis of fusion constructs encoding the DNA-binding domain of yeast GAL4 and portions of B failed to reveal a transcriptional activation domain in the B protein. However, an amino-terminal domain of B was found to recruit a transcriptional activation domain by an interaction with C1. Formation of this complex resulted in the activation of a synthetic promoter containing GAL4 recognition sites, demonstrating that this interaction does not require the normal target promoters for B and C1. B and C1 fusions with yeast GAL4 DNA-binding and transcriptional activation domains were also found to interact when synthesized and assayed in yeast. The domains responsible for this interaction map to a region that contains the Myb homologous repeats of the C1 protein and to the amino terminus of the B protein, which does not contain the b-HLH motif. These studies suggest that the regulation of the maize anthocyanin pigmentation pathway involves a direct interaction between members of two distinct classes of transcriptional activators. PMID: 1577278 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 275: Blood. 1992 May 1;79(9):2296-302. Isolation and molecular characterization of the human CD34 gene. He XY, Antao VP, Basila D, Marx JC, Davis BR. Geraldine Brush Cancer Research Institute, Medical Research Institute of San Francisco, CA 94115. The human CD34 surface antigen is selectively expressed on hematopoietic stem/progenitor cells, suggesting that it plays an essential role in early hematopoiesis. Using a 1.5-kb partial human CD34 cDNA sequence, RNA-polymerase chain reaction (PCR), and rapid amplification of cDNA ends (RACE) methods, we cloned and sequenced the full-length (2.65 kb) cDNA. The cDNA encodes a type I transmembrane protein with no obvious homology to other known proteins. The entire CD34 gene of 28 kb was cloned, and the coding sequences mapped to eight exons. Mapping of the 5' termini of mRNAs by 5'-RACE and RNAase protection analyses has indicated that the human CD34 gene uses multiple transcription initiation sites. Analysis of the upstream regulatory sequences revealed the absence of TATA and CAAT box sequences, and the presence of myb, myc, and ets-like DNA binding motifs. We have identified significant homology between human and mouse CD34 genes in 5' and 3' untranslated regions, amino acid coding sequences, and 5' flanking sequences. This investigation of the CD34 gene should facilitate study of the function and regulation of this stem cell antigen. PMID: 1373971 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 276: J Biol Chem. 1992 Apr 25;267(12):8222-9. Stable expression of HB24, a diverged human homeobox gene, in T lymphocytes induces genes involved in T cell activation and growth. Deguchi Y, Thevenin C, Kehrl JH. Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892. A diverged homeobox gene, HB24, which is known to be induced following lymphocyte activation, was introduced into Jurkat T cells under the control of a constitutive promoter. Stable transfectants of HB24 were established that expressed high levels of HB24 mRNA and possessed an altered phenotype suggestive of activated T cells. A number of genes known to be induced following T cell activation and associated with cell growth were increased in the transfectants, including c-fos, c-myc, c-myb, HLA-DR, lck, NF-kappa B, interleukin-2 and interleukin-2 receptor alpha (IL-2R alpha). Analysis of IL-2R alpha expression by transient transfection of IL-2R alpha promoter constructs into the HB24 transfectants revealed constitutive expression (about 60% of phytohemagglutinin- and phorbol ester-activated Jurkat cells) that was dependent on the kappa B site in the IL-2R alpha promoter. Furthermore, as a consequence of the increased HB24 mRNA levels, the Jurkat HB24 transfectants proliferated more rapidly than control cell lines. Thus, stable expression of HB24 confers an activation phenotype on a human T cell line, implicating this gene as an important transcriptional factor during T cell activation and growth. PMID: 1349016 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 277: Rinsho Ketsueki. 1992 Apr;33(4):467-72. [A case report of AML M0:CD7, 33 (+) AML M0 case initially presented with cervical lymphadenopathy] [Article in Japanese] Horiguchi J, Yamamura S, Nemoto T, Fujikawa T, Inaba S, Yamazaki Y, Yamada H. Department of Internal Medicine, Aoto Hospital, Jikei University, School of Medicine. A 59-year-old man was admitted because of generalized lymphadenopathy with fever and vomiting. His peripheral blood showed leukocytosis with a WBC of 93,500/microliters, and the bone marrow picture revealed a predominance of blast cells. The blasts were negative for peroxidase, alpha-naphthyl butyrate esterase and PAS, and had the phenotype of CD 7, 13 and 33 positive. A diagnosis of AML M0 was made, based on the criteria of the NCI-sponsored workshop in 1988. His initial status had been compromised by acute renal failure which necessitated hemodialysis. He responded partially to chemotherapy consisting of daunorubicin, cytarabine and prednisolone. However leukemia recurred and the patient suffered from various episodes of infection and died six months after admission. The Southern blotting showed the germ line configuration for TCR-beta chain and immunoglobulin heavy chain genes. No messenger RNA was detected for myeloperoxidase, c-myc and c-jun, while c-fms, c-fos and c-myb were expressed on Northern blotting. It is intriguing to detect c-fms and c-fos expression in these poorly differentiated leukemic cells. Publication Types: Case Reports PMID: 1602610 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 278: Oncogene. 1992 Apr;7(4):653-60. Erratum in: Oncogene 1992 Jul;7(7):1459. SCL is coexpressed with GATA-1 in hemopoietic cells but is also expressed in developing brain. Green AR, Lints T, Visvader J, Harvey R, Begley CG. Department of Haematology, Cambridge, UK. The SCL gene encodes a putative transcription factor with a basic helix-loop-helix (B-HLH) motif and is known to be predominantly expressed in erythroid cells. Here we also demonstrate expression of SCL mRNA in normal mast cells, mast cell lines and megakaryocytic cell lines. SCL is therefore expressed in the same three lineages as GATA-1, a well-recognized hemopoietic transcription factor. SCL and GATA-1 mRNA were also co-expressed in interleukin 3-dependent primitive myeloid lines. In murine erythroleukemia (MEL) cells SCL and GATA-1 underwent coordinated biphasic modulation during hexamethylene bisacetamide (HMBA)-induced erythroid differentiation. The kinetics of SCL and GATA-1 mRNA expression was inversely correlated with changes in ID, a negative regulator of B-HLH proteins, and was distinct from changes in MYC, MYB and erythropoietin receptor transcripts. During myeloid differentiation of K562 cells, SCL and GATA-1 mRNA levels also underwent biphasic modulation. Thus SCL and GATA-1 are coordinately expressed in multiple hemopoietic lineages and coordinately regulated during induced erythroid and myeloid differentiation. In nonhemopoietic tissues SCL was only detected in adult and developing brain where GATA-1 is reportedly not expressed. In day 14.5 embryos analysed by in situ hybridization, SCL transcripts were detected in post-mitotic neurons in the metencephalon and roof of the mesencephalon. This suggests a previously unexpected role for SCL in neural differentiation. PMID: 1565464 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 279: Virology. 1992 Mar;187(1):280-9. Measles virus inhibits mitogen-induced T cell proliferation but does not directly perturb the T cell activation process inside the cell. Yanagi Y, Cubitt BA, Oldstone MB. Department of Neuropharmacology, Scripps Research Institute, La Jolla, California 92037. Measles virus (MV) inhibits lymphocyte function in patients, as well as in cells infected in vitro. The proliferation of phytohemagglutinin-stimulated T lymphocytes is suppressed by in vitro MV infection, as shown by the diminished incorporation of [3H]thymidine into DNA and the reduced frequency of cells in the S phase of the cell cycle, as compared with mock-infected cells. MV infection itself, however, does not completely block DNA synthesis in infected cells, because infected T cells expressing MV antigens on the cell surface, isolated by fluorescence-activated cell sorter, could still proliferate. Northern blot analysis indicated that the expression of genes induced during T cell activation, such as those encoding interleukin 2 (IL-2), c-myc, IL-2 receptor, IL-6, c-myb, and cdc-2, was not significantly suppressed in MV-infected cells, suggesting that MV does not interfere with the T cell activation process. When anti-MV serum or carbobenzoxy-D-Phe-L-Phe-Gly, a synthetic oligopeptide known to inhibit MV-induced fusion, was added 24 hr after infection, the inhibition of T cell proliferation was reversed in a dose-dependent manner. From these results we propose a model for the inhibition of T cell proliferation by MV; MV glycoproteins expressed on the cell surface of infected cells interact with the MV receptor or other molecules on the cell membrane of adjacent T cells, which in turn affects the proliferation of those T cells. PMID: 1736530 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 280: Blood. 1992 Mar 1;79(5):1319-26. Defective c-myc and c-myb RNA turnover in acute myeloid leukemia cells. Baer MR, Augustinos P, Kinniburgh AJ. Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY 14263. Dysregulated expression of the c-myc and c-myb protooncogenes has been implicated in the pathogenesis of acute myeloid leukemia (AML). To elucidate mechanisms of c-myc dysregulation in AML cells, we studied c-myc RNA turnover in peripheral blood blasts from eight patients using actinomycin D transcription blockade. Rapid c-myc RNA turnover was seen in cells from six patients, with half-lives of approximately 30 minutes, similar to those reported in normal myeloid cells, in HL-60 cells, and in other cell lines. c-myc RNA turnover was prolonged in cells of the other two patients, with half-lives of greater than 75 minutes. c-fos RNA turnover was rapid in blasts from all eight patients, with half-lives of approximately 15 minutes. Stabilization of GM-CSF transcripts was not observed. In contrast, c-myb RNA half-lives were greater than 75 minutes in cells of the two patients with prolonged c-myc RNA turnover, as compared to 30 minutes in cells of the other six patients. Enhanced stability of both c-myc and c-myb RNA species suggests that a defect exists in a trans-acting factor that destabilizes both of these normally labile RNAs. Incomplete correlation between c-myc RNA levels and half-lives indicates regulation of c-myc expression at the level of transcription or nuclear transport in addition to posttranscriptional regulation. PMID: 1371419 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 281: Proc Natl Acad Sci U S A. 1992 Feb 15;89(4):1291-5. Myb and Ets proteins cooperate in transcriptional activation of the mim-1 promoter. Dudek H, Tantravahi RV, Rao VN, Reddy ES, Reddy EP. Wistar Institute of Anatomy and Biology, Philadelphia, PA 19104. In the generation of the acutely transforming avian retrovirus E26, both myb and ets genes have been transduced, leading to the production of a Gag-Myb-Ets fusion protein. This co-occurrence of v-myb and v-ets oncogenes suggests that the two might have a functional relationship. To look for such a relationship, we tested the transcriptional activation activity of Myb alone or with coexpressed Ets-1 or Ets-2. Using the promoter of the v-Myb-inducible mim-1 gene as a target, we found that full-length c-Myb gene products were poor activators of transcription, while an oncogenic (truncated) form of this protein was a strong trans-activator. However, coexpression of Ets-2 with full-length or truncated forms of Myb greatly increased trans-activation. Coexpression of Ets-1, Fos, Jun, or Myc with Myb did not increase trans-activation of the mim-1 promoter. The ability of Myb and Ets-2 to transactivate was cooperative, since Ets-2 alone gave little or no activation. Bacterially synthesized Ets-2 protein was found to bind specifically to the mim-1 promoter, suggesting that it may be a target for both Myb and Ets proteins. Thus, Myb and Ets proteins can cooperate in transcriptional activation, and their co-occurrence in the E26 virus may reflect a functional relationship between these two oncoproteins. Truncated forms of Myb may have a reduced need for cooperating factors such as Ets-2, and this might constitute an important mechanism associated with oncogenic activation. PMID: 1741383 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 282: J Immunol. 1992 Feb 1;148(3):934-42. Constitutive versus cell cycle regulation of c-myb mRNA expression correlates with developmental stages in murine B lymphoid tumors. Catron KM, Purkerson JM, Isakson PC, Bender TP. Department of Microbiology, School of Medicine, University of Virginia, Charlottesville 22908. The expression of c-myb mRNA is differentially regulated in murine B lymphoid tumors such that B cell lymphomas and plasmacytomas contain significantly less c-myb mRNA than pre-B cell lymphomas. To examine the low level of c-myb mRNA expression in the murine B cell lymphoma cell line BCL1, nonessential amino acid starvation was used to block these cells in a G1 state. When BCL1 cells were released from this block, a 7- to 10-fold increase in c-myb mRNA was detected in late G1 and S phase cells relative to that detected in exponentially growing BCL1 cells. This increase was not inhibited by aphidicolin. To determine whether cell cycle regulation of c-myb mRNA expression occurred during exponential growth in both murine pre-B cell lymphoma and B cell lymphoma cell lines, elutriation was used to separate exponentially growing cell populations. An increase in c-myb mRNA expression was seen in late G1 and S phase fractions from B cell lymphoma cell lines. In contrast, c-myb mRNA levels remained constant in elutriation fractions isolated from pre-B cell lymphoma cell lines. Expression of c-myb mRNA was not detected in exponentially growing or in Go serum-stimulated murine fibroblasts. These results indicate that constitutive vs cell cycle regulation of c-myb mRNA expression is related to the state of differentiation in murine B lymphoid tumors and suggest that a switch in regulation may occur during normal B cell development. PMID: 1730880 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 283: Semin Diagn Pathol. 1992 Feb;9(1):75-89. Malignant histiocytosis in childhood: a distinctive CD30-positive clinicopathological entity associated with a chromosomal translocation involving 5q35. Nezelof C, Barbey S, Gogusev J, Terrier-Lacombe MJ. Groupe de Pathologie Pediatrique, Hopital des Enfants Malades, Paris, France. The clinicopathological data on 20 cases of malignant histiocytosis (MH) collected over a period of 30 years at the Hopital des Enfants Malades (Paris) are reported. Childhood MH was characterized by disseminated, frequently tender lymphadenopathy (19/20), skin (8/20), bone (6/20), and soft tissue localizations (7/20). These features were usually accompanied by fever, deterioration of general condition, and hematological abnormalities including anemia, thrombocytopenia, and occasionally fibrinopenia. These manifestations were clinically suggestive of a diagnosis of a severe neoplastic blood disease, although this hypothesis was not entertained for a long time because of the initial absence of abnormal cells in the blood and bone marrow. MH was characterized by the proliferation of large "histiocyte-like," usually mononucleated cells. When suitable material was available, MH cells appeared to react positively with acid-phosphatase, alpha-naphthyl acetate esterase (ANAE), alpha-antichymotrypsin, and antibodies directed against EMA, HLA DR, CD25, CD30, CD68, and CD71. No B- and T-cell antigens (except for one case) have been detected. Due to the frequent abundance of accompanying granulocytes, lymphoid, and plasma cells, and the presence of areas of necrosis, an initial correct diagnosis of MH was often difficult to establish on skin (four cases), bone (two), and soft tissue (three) biopsies. In lymph nodes, the sinusoidal and perifollicular topography of cell proliferation represented a highly reliable morphological feature. A permanent cell line (DEL) was obtained from a pleural effusion showing a t(5;6)(q35;p21) translocation and a monoallelic immunoglobulin (IgjH) rearrangement and consistent levels of expression of c-fms, c-myc, c-myb, c-ki-ras and c-fgr. Since an identical 5q35 breakpoint has been reported in four other MH cell lines with a comparable phenotype and in several isolated published cases, this chromosomal abnormality provides a highly valuable argument for individualizing an authentic malignancy of the mononuclear phagocyte system (MPS) in childhood, among the rather heterogeneous group of the CD30+ anaplastic large cell lymphomas. Publication Types: Review Review, Tutorial PMID: 1313990 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 284: Clin Immunol Immunopathol. 1992 Jan;62(1 Pt 1):119-23. Histological detection of c-myb and c-myc proto-oncogene expression in infiltrating cells in cutaneous lupus erythematosus-like lesions of MRL/l mice by in situ hybridization. Kitajima T, Furukawa F, Kanauchi H, Imamura S, Ogawa K, Sugiyama T. Department of Dermatology, Faculty of Medicine, Kyoto University, Japan. A relationship between lymphocytic activation and the overexpression of proto-oncogenes such as c-myb or c-myc has been demonstrated in human autoimmune disease. In autoimmune-prone MRL/l mice, which spontaneously develop lupus erythematosus (LE)-like lesions on the back, increased expression of myb RNA has been found in the lymphoid organs. We detected the overexpression of c-myb and c-myc proto-oncogenes in infiltrating cells in the cutaneous lesions of MRL/l mice by using in situ hybridization. No specific hybridization signals of either of the probes used were seen in the nonlesional skin of MRL/l mice or in the apparently normal skin of aged MRL/n and young MRL/l mice. These results suggest that the increased expression of myb and myc proto-oncogenes in the cutaneous LE-like lesions of MRL/l mice is related to a state of activation in the infiltrating cells and is involved in the development of these lesions. PMID: 1728975 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 285: Am J Med Sci. 1992 Jan;303(1):16-24. Oncogene alterations in rat colon tumors induced by N-methyl-N-nitrosourea. Alexander RJ, Buxbaum JN, Raicht RF. Research Service, D.V.A. Medical Center, New York, NY 10010. The authors assayed oncogene alterations in rat colon tumors induced by the direct-acting chemical carcinogen, N-methyl-N-nitrosourea (MNU). DNA isolated from 34 adenomas and eight carcinomas, as well as adjacent normal colon, of 11 rats was assayed by Southern blotting for restriction fragment length polymorphisms and gene amplifications and deletions in 13 oncogenes known to be involved in human or other animal tumors. In addition to finding apparent point mutations or other small alterations in the fos and abl genes in individual rat colon tumors, the authors observed what appear to be larger alterations (ie, rearrangements, or intragenic insertions or deletions) in the H-ras and myb loci in several tumors. In contrast, no changes in the K-ras, N-ras, myc, N-myc, neu, raf, fms, met, and hst genes were seen in any of these tumors. The frequency of myb gene alterations was higher in carcinomas than in adenomas, suggesting that these changes occurred relatively late during tumorigenesis and were not direct effects of the carcinogen. In addition, the finding of alterations in two or three oncogenes in several MNU-induced rat colon tumors suggests the possibility of more widespread genomic lesions in this model. PMID: 1728873 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 286: Int J Clin Lab Res. 1992;22(3):159-64. Detection of a transcriptional block in the first intron of the human c-myb gene. Castellano M, Golay J, Mantovani A, Introna M. Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. The levels of expression of the murine c-myb gene, like those of several other proto-oncogenes, can be controlled by a block of transcriptional elongation within the first intron of the gene. We have performed run-off experiments with double- and single-stranded probes on the myelomonocytic cell line U937, and show that this mechanism of transcriptional arrest is true also for the human c-myb gene and takes place within the first intron. Furthermore, we have sequenced the entire first intron of the human c-myb gene, and discuss the sequence structure in relation to its putative ability to arrest RNA polymerase II and its high degree of homology with the equivalent murine intron. PMID: 1520913 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 287: Oncology. 1992;49(3):209-14. Pattern of growth factor, proto-oncogene and carcinoembryonic antigen gene expression in human colorectal carcinoma cell lines. La Rocca RV, Park JG, Danesi R, Del Tacca M, Steinberg SM, Gazdar AF. Department of Medical Oncology, J. Graham Brown Cancer Center, University of Louisville, Ky. The aim of the present study was to examine whether the expression of growth factor genes, proto-oncogenes and carcinoembryonic antigen (CEA) gene in human colorectal cancer cell lines was related to their clinicobiological behavior. A significant variability among cell lines was detected for both insulin-like growth factor II and transforming growth factor beta gene message. Detectable levels of c-myc, Her-2, c-myb, K-ras and EGF receptor mRNA were found in most cell lines, whereas only 1/11 and 2/11 cell lines were positive for N-myc and c-sis message, respectively. N-myc expression was limited to a cell line originated from a tumor with neuroendocrine features, while high levels of K-ras message were found only in a cell line derived from a radioresistant tumor. CEA mRNA levels correlated well with the concentration of antigen in each cell line. On the basis of these results, our findings demonstrated that human colorectal cancer cell lines show heterogeneous expression of growth factor and CEA genes and proto-oncogenes; however, with the exception of K-ras, N-myc and CEA, other correlations between gene expression and the clinicobiological characteristics of these cell lines could not be demonstrated. PMID: 1495747 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 288: Neoplasma. 1992;39(6):343-7. Regulation of the proto-oncogenes c-sis, c-fos, c-myc and c-myb in acute myeloid leukemias. Strassburg CP, Neubauer V, Poliwoda H, Benter T. Department of Hematology and Oncology, Hannover School of Medicine, Germany. RNA transcriptional levels of the proto-oncogenes c-sis, c-fos, c-myb and c-myc were measured in peripheral blood leukemic blast cells of 16 patients with acute myeloid leukemia (AML) of different FAB subtypes, 8 being at diagnosis and 8 upon relapse. The studied proto-oncogenes were found to be regulated but varied considerably within morphologically identical subtypes. This is consistent with the clinically observable diverse behavior of seemingly identical AMLs as to the course and outcome of the individual disease. Overexpression of c-sis and c-myc was found more often in AML upon relapse than at diagnosis and in two cases overexpression not found at diagnosis was present at relapse. This implies alterations of biological behavior in the course of antileukemic drug therapy. A decline of c-myb expression was observed in one patient studied throughout therapy which was found to be associated with a complete but transient hematological remission after chemotherapy. PMID: 1491723 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 289: Cytometry. 1992;13(6):653-8. Protooncogene expression in subpopulations of cells from leukemia patients. Hulette BC, Banavali SD, Finke DP, Gopal V, Preisler HD. University of Cincinnati Medical Center, Ohio 45267-0508. This report describes a method for preserving the light scatter patterns of cells in which myc and myb expression are being measured. Exposure of cells to 1% paraformaldehyde for 72 h prior to antibody staining for myc and myb proteins preserved the light scatter patterns. Using this method, myc and myb expression was found to be highest in lymphocytes and monocytes and lowest in granulocytes. The measurement of differences in the level of expression of these genes in subpopulations of leukemia cells obtained from individual patients is possible as is assessment of the levels of expression amongst normal and leukemia cells present in the same patient. PMID: 1451597 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 290: Gene Expr. 1992;2(3):215-30. Sequences within the R region of the long terminal repeat activate basal transcription from the HIV-1 promoter. Boris-Lawrie KA, Brady JN, Kumar A. Department of Biochemistry and Molecular Biology, George Washington University Medical Center, Washington, D.C. 20037. The importance of the R region in basal human immunodeficiency virus type 1 (HIV-1) transcription was addressed by comparing a panel of HIV-1 R region mutants using in vitro and in vivo assays. Using deletion, base substitution mutants, and compensatory mutants, the precise R region sequences essential for basal HIV-1 promoter activity in vitro were mapped to sequences between +17 to +21. Within this regulatory domain, nucleotides +19 and +21 appear to be critical. The effect of these mutations on steady state RNA levels in transfected cells has been analyzed by S1 nuclease protection assay using uniformly labeled probes. Two main conclusions may be drawn from these studies. First, HIV-1 basal transcription is abundant, with the majority of correctly initiated transcripts truncated between sequences +57 to +70. Second, analysis of the compensatory mutants indicates the secondary structure of the nascent R region RNA is not an obligate requirement for the production of the truncated transcripts. Mutations in R region primary sequence that selectively abolish the production of the truncated transcripts in vivo also exhibit reduced promoter activity in vitro. The appearance of high levels of truncated transcripts raise the interesting possibility that-similar to c-myc, c-myb, and c-fos--basal HIV-1 expression is regulated by transcription elongation. PMID: 1450662 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 291: Oncol Res. 1992;4(7):291-8. HL-60 cells isolated for resistance to vincristine are defective in 12-O-tetradecanoylphorbol-13-acetate induced differentiation and the formation of a functional AP-1 complex. Ma L, Krishnamachary N, Perbal B, Center MS. Division of Biology, Kansas State University, Manhattan 66506. HL-60 cells isolated for resistance to vincristine are multidrug resistant and defective in the cellular accumulation of drug. Further studies demonstrate that these cells are also highly defective in 12-O-tetradecanoylphorbol-13-acetate (TPA) induced differentiation to macrophages. Analysis of this system demonstrates that certain protooncogenes which may contribute to differentiation are expressed at similar levels in sensitive and resistant cells. Thus, treatment of cells with TPA results in a reduction in the levels of c-myb and c-myc mRNA, while the expression of c-fos, c-jun, and junB is greatly enhanced. Immunoprecipitation experiments also demonstrate a TPA induced increase in the c-jun protein in both sensitive and resistant cells. Gel mobility shift assays show that TPA induces AP-1 formation in sensitive cells, whereas in parallel experiments with the HL-60/Vinc isolate, AP-1 is essentially absent. It has been found, however, that in resistant cells which have reverted to drug sensitivity, the levels of TPA inducible AP-1 is essentially identical to that of sensitive cells. Revertant and sensitive cells differentiate at similar levels in the presence of TPA. These studies therefore demonstrate that HL-60/Vinc cells are defective in the TPA induction of a functional AP-1 complex and that this may account for the inability of these cells to differentiate to macrophages. The molecular basis of the finding that AP-1 is not formed in resistant cells remains to be determined. PMID: 1450490 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 292: Pediatr Hematol Oncol. 1992 Jan-Mar;9(1):57-63. Oncogene RNA expression in three human lymphoblastic leukemia cell lines lymphocytes. Goldman J, McGuire WA. Pediatric Hematology/Oncology Division, James Whitcomb Riley Hospital for Children, Indianapolis, Indiana 46202-5225. We have explored the RNA oncogene expression by three human acute lymphoblastic leukemia lines, NALM-6, MOLT-3, and REH. We compared such expression with that of normal human lymphocytes. Marked differences in the RNA expression of the third exon of c-myc, v-myb, v-Hras, N-ras, v-fes, and v-fos were found. We noted minimal or no differences in the RNA expression of v-abl, B-lym, v-erb-B, c-ets, v-fms, v-kras, v-mos, v-raf, and v-sis. PMID: 1373069 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 293: EMBO J. 1992 Jan;11(1):115-26. Autocrine growth induced by kinase type oncogenes in myeloid cells requires AP-1 and NF-M, a myeloid specific, C/EBP-like factor. Sterneck E, Muller C, Katz S, Leutz A. Zentrum fur Molekulare Biologie Heidelberg, University of Heidelberg, FRG. The nuclear oncogenes v-myc or v-myb specifically transform avian myeloid cells. In both cases, the transformed cells remain dependent on chicken myelomonocytic growth factor (cMGF). This factor dependence can be relieved by expression of kinase-type oncogenes such as v-mil or v-erbB, leading to expression of cMGF and autocrine growth stimulation. In erythroid cells the same kinase-type oncogenes cause transformation but do not induce cMGF expression. Here we investigated the molecular mechanisms of the observed lineage specific oncogene collaboration. We found that kinase-type oncogenes and TPA activate the cMGF promoter via AP-1 like transcription factors. The activation of the cMGF promoter is, however, strictly dependent on the binding of nuclear proteins to both halves of an inverted repeat adjacent to the AP-1 binding site. These proteins are related to C/EBP. They are expressed exclusively in myeloid cells and were therefore termed NF-M. Our results indicate that the lineage specific cooperation of kinase type oncogenes with v-myb or v-myc in leukemia formation is based on the concerted action of AP-1 and NF-M on the cMGF promoter. PMID: 1346759 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 294: J Virol. 1992 Jan;66(1):512-23. Activation of the c-myb locus is insufficient for the rapid induction of disseminated avian B-cell lymphoma. Pizer ES, Baba TW, Humphries EH. Department of Microbiology, Southwestern Medical School, Dallas, Texas 75235. We have previously reported that infection of 9- to 13-day-old chicken embryos with RAV-1 results in rapid development of a novel B-cell lymphoma in which proviral insertion has activated expression of the c-myb gene (E. Pizer and E. H. Humphries, J. Virol. 63:1630-1640, 1989). The biological properties of these B-cell lymphomas are distinct from those associated with the B-cell lymphomas that develop following avian leukosis virus proviral insertion within the c-myc locus. In an extension of this study, more than 200 chickens, infected as 10- to 11-day-old embryos, were examined for development of lymphomas that possess disrupted c-myb loci. Fourteen percent developed disseminated B-cell lymphoma. In the majority of these tumors, the RAV-1 provirus had inserted between the first and second exons that code for p75c-myb. However, insertions between the second and third exons and between the third and fourth exons were also detected. In situ analysis of myb protein expression in tumor tissue revealed morphological features suggesting that the tumor originates in the bursa. Within the bursa, the lymphoma appeared to spread from follicle to follicle without compromising the structural integrity of the organ. Tumor masses in liver demonstrated heterogeneous levels of myb protein suggestive of biologically distinct subpopulations. In contrast to the morbidity data, immunohistological analysis of bursae from 4- to 6-week-old chickens at risk of developing lymphomas bearing altered c-myb loci revealed lesions expressing elevated levels of myb in 16 of 19 birds. The activated myb lymphoma displayed very poor capacity to proliferate outside its original host. Only 1 of 33 in vivo transfers of tumor to recipient hosts established a transplantable tumor. None of the primary tumor tissue nor the transplantable tumor exhibited the capacity for in vitro proliferation. Similar experimental manipulation has yielded in vitro lines established from avian B-cell lymphomas expressing elevated levels of c-myc or v-rel. The dependence on embryonic infection for development of activated-myb lymphoma suggests a requirement for a specific target cell in which c-myb is activated by proviral insertion. It is likely, moreover, that continued tumor development requires elevated expression of myb proteins within a specific cell population in a restricted stage of differentiation. PMID: 1309260 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 295: Nippon Hinyokika Gakkai Zasshi. 1991 Dec;82(12):1930-8. [Oncogene amplification and inactivation of tumor suppressor genes in urological malignant tumors--the application of restriction fragment length polymorphism analysis] [Article in Japanese] Kunimi K, Uchibayashi T, Hisazumi H. Department of Urology, School of Medicine, Kanazawa University. We applied restriction fragment length polymorphism (RFLP) analysis to 24 cases of renal cell carcinomas (RCC), 18 cases of prostate adenocarcinomas (PC), and 11 cases of transitional cell carcinomas (TCC) in the renal pelvis to study the oncogene amplification and inactivation of tumor suppressor genes. All of the cases showed no amplification nor gross rearrangements of the Harvey ras, c-myc, c-fos, c-myb, EGFR and PDGFR. In contrast, RFLP analyses demonstrated allelic losses interpreted as inactivational events of TSGs among the tumor forms studied. RCC had allelic losses on the short arm of chromosome 3 (3p) (68%), the long arm of chromosome 18 (18q) (33%), Y chromosome (29%), and 17p (27%) at high frequencies. PC showed frequent allelic losses on 16q (67%), 8p (50%), 18q (43%), 10p (40%), and 10q (38%). TCC had allelic losses on 17p (73%), 11p (64%), and 9p (40%). It was likely that the cases with the more malignant grade tumor had the more allelic losses. PMID: 1685754 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 296: Anticancer Res. 1991 Nov-Dec;11(6):2175-9. C-myc overexpression, c-mil, c-myb expression in a breast tumor cell line. Effects of estrogen and antiestrogen. Collyn-d'Hooghe M, Vandewalle B, Hornez L, Lantoine D, Revillion F, Lefebvre J, Kerckaert JP. U 124 INSERM, Lille, France. In breast tumor cell lines, c-myc amplification is frequently associated with estrogen unresponsiveness. We, however, succeeded in characterizing an estrogen-responsive cell line VHB1 derived from a duct cell carcinoma, which exhibits c-myc amplification and overexpression. We therefore studied the effects of estrogen and antiestrogen on c-myc expression in this particular cell line. We also investigated these effects on the expression of c-mil and c-myb oncogenes, also expressed but not amplified in VHB1 cells. Short-(1 h) and long-(72 h) term stimulations were performed. Our experiments showed that estradiol (E2 10(-8) M) was still able to stimulate c-myc expression equally either after short or long-term treatment. In the same way, the antiestrogen 4-hydroxytamoxifen equally decreased c-myc expression but the reversal effect of E2 after long-term antiestrogen treatment was more pronounced than after short-term treatment. The effects of E2 and 4-OH Tam on the expression of the not-amplified c-mil and c-myb oncogenes were stronger than those observed on c-myc expression; however, the E2 reversal effect was identical either after short or long-term antiestrogen treatment. Our results may enlighten some aspects of the complex action of some of the early- and late-growth regulated genes in breast cancer. PMID: 1776859 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 297: Oncogene. 1991 Nov;6(11):2129-35. v-erbA oncogene abrogates growth inhibition of chicken embryo fibroblasts induced by retinoic acid. Desbois C, Pain B, Guilhot C, Benchaibi M, Ffrench M, Ghysdael J, Madjar JJ, Samarut J. Immuno-Virologie Moleculaire et Cellulaire, Universite Claude Bernard Lyon-1/CNRS UMR 30, Faculte de Medecine Alexis Carrel, Lyon, France. Retinoic acid inhibits chicken embryo fibroblast (CEF) proliferation by altering the G1 phase of the cell cycle with induction of a strong increase in the generation time. This growth-inhibitory response to retinoic acid is abrogated by expression of the v-erbA oncogene, suggesting an interference between retinoic acid receptors and the v-ErbA oncoprotein. Moreover, CEF expressing either the v-src, v-jun or v-fos oncogenes are also insensitive to retinoic acid treatment. In contrast, CEF expressing either the v-myc, v-myb-ets, v-mil, v-sea or v-erbB oncogenes are still sensitive to retinoic acid. These data strongly suggest functional interferences between the retinoic acid receptors and the AP-1 transcription factor complex in the control of expression of genes involved in CEF proliferation. PMID: 1682867 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 298: Oncogene. 1991 Oct;6(10):1843-50. Erratum in: Oncogene. 1992 May;7(5):1047. Characterization of the human N-ras promoter region. Thorn JT, Todd AV, Warrilow D, Watt F, Molloy PL, Iland HJ. Kanematsu Laboratories, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia. Overexpression of ras proto-oncogenes has been implicated in cancer development. We therefore initiated a study of the human N-ras promoter to determine the regions that control N-ras expression and their potential for interaction with DNA-binding proteins. N-ras CAT constructs were stably integrated into K562 cells by electric field-mediated gene transfer in order to determine functional regions within the human N-ras promoter. A significant proportion of promoter activity was found to lie within a 439 bp fragment comprising an untranslated exon (exon 1) with the adjacent 5' sequence and a small CpG island. A 109 bp [corrected] fragment at the 5' end of exon 1 was essential for promoter activity, while a 45 bp [corrected] deletion from within this region decreased promoter activity by two-thirds. Unlike the human H-ras and mouse K-ras promoters, the N-ras promoter did not exhibit bidirectional activity. DNAse footprinting of the 439 bp fragment revealed seven protected regions, many of which contain sequences homologous to known DNA-binding protein sites (MLTF/myc, CREB/ATF, AP-1, AP-2, myb and E4TF1). In contrast, four putative Sp1 sites did not footprint. Using purified MLTF and appropriate competitors in gel shift and DNAase footprinting assays, we demonstrated binding of MLTF to the MLTF consensus sequence within exon 1. PMID: 1923508 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 299: Oncogene. 1991 Oct;6(10):1813-24. Analysis of viral and cellular gene expression during progression and suppression of the transformed phenotype in type 5 adenovirus-transformed rat embryo cells. Duigou GJ, Su ZZ, Babiss LE, Driscoll B, Fung YK, Fisher PB. Department of Neurological Surgery, Columbia University, College of Physicians and Surgeons, New York, New York 10032. Transformation of secondary Sprague-Dawley rat embryo (RE) cells with type 5 adenovirus (Ad5) results in morphologically transformed cells which can undergo a series of sequential changes resulting in enhanced expression of the transformed phenotype, a process termed progression. Selection for a progressed phenotype often occurs after growth in agar or tumor formation in nude mice, and this process is reversible following treatment of cells with 5-azacytidine. In the present study we have analyzed a series of clonal populations of Ad5-transformed RE cells representing different stages in a defined progression lineage. Progression was not associated with alterations in the steady-state levels of mRNA produced by the viral transforming genes, E1A and E1B, or the cellular gene, c-myc. In addition, the tumor-promoting agent 12-O-tetradecanoyl-phorbol-13-acetate (TPA), which induces expression of a progressed phenotype in Ad5-transformed RE cells, did not significantly alter the RNA transcription rates of the Ad5 E1A or E1B genes, the TPA-inducible gene TPA-S1 or the TPA-responsive genes Pro1 or protein kinase C. TPA did, however, increase by 1 h the steady-state level of c-fos mRNA, but this effect was similar in both progressed and unprogressed cells. Progression also did not involve a change in the RNA transcription rate of a number of cellular and viral genes, including actin, c-Ha-ras, c-myc, v-fos, erbB, TGF-alpha, TGF-beta, Pro-2, transin, TPA-R1, v-myb and c-mos, or other adenovirus genes in addition to E1A and E1B, including E2A and E4. Immunoblotting analysis using E1B polyclonal antiserum further indicated that progression was not associated with changes in the levels of an Mr 21,000 polypeptide encoded by E1B. Similarly, immunoprecipitation analysis with an Ad2 E1A monoclonal antibody indicated similar levels of the Mr 55,000 and 48,000 E1A polypeptides, as well as coprecipitated proteins of Mr 300,000, 107,000 and 105,000 [which is the retinoblastoma (Rb) protein], in E11 and E11-NMT cells. Immunoprecipitation of cell lysates with a monoclonal antibody specific for the Mr 105,000 Rb protein further demonstrated that progression also was not associated with a change in the level or state of phosphorylation of the Rb protein. However, transfection of a human Rb gene (also containing a neomycin resistance gene) into Ad5-transformed RE cells was more inhibitory, with respect to formation of G418-resistant colonies, in unprogressed than in progressed Ad5-transformed RE cells.(ABSTRACT TRUNCATED AT 400 WORDS) PMID: 1923506 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 300: Am J Obstet Gynecol. 1991 Sep;165(3):640-6. Expression and amplification of the HER-2/neu (c-erbB-2) protooncogene in epithelial ovarian tumors and cell lines. Tyson FL, Boyer CM, Kaufman R, O'Briant K, Cram G, Crews JR, Soper JT, Daly L, Fowler WC Jr, Haskill JS, et al. Department of Medicine, Duke University Medical Center, Durham, NC 27710. Amplification of the c-erbB-2 protooncogene has been associated with a poor prognosis in human breast and ovarian cancers. Our study was undertaken to examine whether amplification, rearrangement, or overexpression of c-erbB-2 and other protooncogenes was frequently observed in epithelial ovarian cancers. c-erbB-2 was expressed in 87% of 22 ovarian cancers analyzed, but expression was significantly increased in only one of the 22 tumor specimens. In this case elevated c-erbB-2 expression was associated with dramatic amplification of the gene. In another tumor a 3.8 kb EcoRI fragment was found, in addition to the usual 4.4 and 6.0 kb fragments; this is consistent with a possible gene rearrangement or a restriction fragment length polymorphism. To place these results in perspective, expression of several other protooncogenes has been examined in ovarian carcinomas. The c-fos, c-myc, n-myc, c-fms, and c-Ha-ras protooncogenes were expressed in different fractions of tumors, but expression of l-myc, c-erbB, c-myb, c-sis, and c-mos was not detectable. Aside from c-erbB-2, neither amplification nor rearrangement was observed among the other protooncogenes studied. Expression of c-erbB-2, c-fms, c-myc, n-myc, c-fos, and c-Ha-ras deserves further evaluation as a prognostic factor in ovarian cancer. PMID: 1679963 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 301: Rinsho Ketsueki. 1991 Sep;32(9):986-90. [Altered expression of protooncogenes during clinical course in an AML case transformed from MDS] [Article in Japanese] Fujikawa T, Horiguchi J, Iizuka K, Nemoto T, Iwase S, Yamamura S, Inaba S, Yamazaki Y, Sano S, Yamada H. Department of Internal Medicine, Aoto Hospital, Jikei University School of Medicine. The changes of expression of oncogenes in the mononuclear cells of MDS case was studied during his clinical course, in series. His bone marrow was considered to maintain its function partly in initial stage, since both peripheral blood and bone marrow responded to clinical episodes. However, his hematopoietic function was gradually impaired with the disease evolution to AML. We examined the expression of four oncogenes in the mononuclear cells of his three clinical stages, early RAEB-t, RAEB-t and AML, to study the cause of transformation from MDS to AML. Early RAEB-t cells expressed all oncogenes studied other than c-myb, while only c-myc was weakly observed in RAEB-t. AML cells expressed c-myc, c-jun and c-myb, except for c-fms. The expression of c-fms and c-jun of early RAEB-t was considered to reflect the monocytosis induced by infections, and the expressions of c-myb and c-myc of AML cells were regarded as one of malignant signs of tumor transformation. These findings suggest that the evolutional transformation of MDS to AML was affected by the altered expression of oncogenes. Publication Types: Case Reports PMID: 1942545 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 302: Hum Cell. 1991 Sep;4(3):230-6. [The physiological function of human endometrium] [Article in Japanese] Watanabe J, Hata H, Masuda K, Kuramoto H. Department of Obstetrics and Gynecology, School of Medicine, Kitasato University, Sagamihara, Japan. The cyclic change of human endometrial cells are controlled by the interaction between hypothalamus, pituitary gland and ovaries, thus making the endometrium proliferate, differentiate, exfoliate and then reproduce. The menstrual cycle is divided into three phases which are called follicle, ovulatory and luteal phase by the morphological change of the ovarium. The endometrial cycle is also classified to proliferative, secretory and menstrual phase. Estradiol (E2) stimulates the proliferation of endometrial cells by the indirect positive mechanism activated by the binding of E2 to E2 receptor. Growth factors (IGF- I, EGF, TGF- alpha etc.) induced by the transcription of the gene promote the proliferation of endometrial cells. Progesterone (P) has antagonistic effects on E2 actions and transform proliferative phase to secretory phase in endometrium. It is suggested that the possible mechanism of carcinogenesis of normal endometrium is the progression of endometrial hyperplasia due to the prolonged and unphysiological exposure to E2. The additional role of oncogenes (fos, fms, myc, myb, erb-B, neu) and growth factors on the mechanism of carcinogenesis of hyperplasia to cancer is very interested. PMID: 1782183 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 303: Biochem Int. 1991 Sep;25(1):151-8. Molecular analysis of cell cycle-related gene expression in anti-HLA class I monoclonal antibody (01.65) treated PHA-activated human T-lymphocytes. Selvatici R, Rubini M, Orlando P, Balboni A, Balugani S, Gandini E. Institute of Medical Genetics, University of Ferrara, Italy. HLA class I antigens seem to be involved in the proliferative response of PHA-activated human T-lymphocytes. We have previously reported that the treatment of PHA-activated peripheral blood mononuclear cells (PBMC) with an anti-HLA class I monoclonal antibody, 01.65, (i) inhibits the tritiated thymidine incorporation, (ii) inactivates cytosolic protein kinase C (PKC) and (iii) causes an increase in the duration of the cell cycle. Northern Blot kinetic analysis of c-fos, c-myc, cdc2, IL-2R, c-myb, ODC, TK and H3, from 10 minutes to 120 hours, was performed in MAb 01.65 treated cultures. We found that the expression of four genes (c-myc, IL-2R, cdc2 and TK) was depressed 24 hours after PHA stimulation. PMID: 1772440 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 304: Am J Hematol. 1991 Aug;37(4):223-7. Enhanced expression of poly(ADP-ribose) synthetase gene in malignant lymphoma. Tomoda T, Kurashige T, Moriki T, Yamamoto H, Fujimoto S, Taniguchi T. Department of Pediatrics, Kochi Medical School, Japan. Over-expression of cellular protooncogenes has been proposed to function in the initiation and maintenance of malignancies. In order to distinguish malignant lymphoma from reactive proliferative diseases, we surveyed the expression levels of three protooncogenes(c-myc, c-fos and c-myb) in malignant lymphoma and reactive proliferative diseases. An increased level of c-myc or c-fos mRNA was observed in one case, respectively, out of three malignant lymphomata. The other cases exhibited no enhancement in protooncogenes. These oncogenes are critically regulated during differentiation, but the half-life of c-myc mRNA was very short, and the level of the mRNA decreased to the initial level very quickly. Thus, the high level of the expression of these oncogenes may not always be maintained in all malignant cells. We then examined the level of mRNA for poly(ADP-ribose) synthetase in those cases. An enhanced expression for the synthetase gene was observed in all five malignant lymphomata tested, but no increase in the level of the mRNA was observed in any reactive proliferative cases or normal lymph nodes. These results suggest that enhanced expression of poly(ADP-ribose) synthetase gene seems to be a common characteristic of protopathic malignant lymphoma. By using the characteristics of malignant lymphoma, the level of mRNA for the synthetase may be applicable for differential diagnosis of malignant lymphoma from several pathologically indistinguishable diseases. PMID: 1907096 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 305: Oncogene. 1991 Aug;6(8):1409-15. Proto-oncogene expression in avian hematopoietic tissues. Schuur ER, Baluda MA. Department of Pathology, UCLA School of Medicine 90024. Previous findings from this laboratory (Kim & Baluda, 1988) have shown that the proto-oncogenes ETS, FPS, MHT (RAF), MYC and REL are expressed in avian myeloblastosis virus (AMV)-transformed cells, whereas the MYB gene is repressed. In this study five different chicken hematopoietic tissues which contained varying concentrations of target cells for AMV transformation were analyzed to determine whether the expression of these proto-oncogenes resulted from, or was altered by, v-myb-induced leukemogenesis. Poly-A+ RNA from hematopoietic cells of 11-13 day yolk sac, 16 day embryonic spleen, 1 day post-hatch bursa of Fabricius, bone marrow and thymus, as well as from chicken embryonic fibroblasts (CEF) was examined by Northern blot analysis. All five proto-oncogenes were found to be expressed in the normal hematopoietic tissues. The ETS, MHT (RAF), MYC, and REL genes, but not FPS, were expressed in CEF. The expression of these five proto-oncogenes was not quantitatively or qualitatively altered in AMV-transformed myeloid cells as compared with their normal counterparts. While their expression is part of the hematopoietic phenotype of the target cells and as such is necessary for susceptibility to AMV transformation, it is not sufficient because thymocytes with a high level of expression are not transformed. This is in contrast to MYB expression, which is totally repressed in leukemic cells but probably not as a result of v-myb expression. PMID: 1886713 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 306: Oncogene. 1991 Aug;6(8):1335-8. Loss of myb expression in an aggressive SJL/J B-cell lymphoma. Sopchak L, Thrush GR, Lerman SP, King SR. Wayne State University School of Medicine, Department of Immunology and Microbiology, Detroit, Michigan 48201. SJL mice spontaneously develop B-cell lymphomas that can be propagated by transplantation into syngeneic mice. These tumors usually have an indolent phenotype and require at least several weeks to produce morbidity following transplantation. However an aggressive lymphoma (RCS5) has been found that produces morbidity within days of transplantation. RCS5 cells fail to express the H-2Ds class I major histocompatibility complex antigen, whereas indolent tumors express H-2Ds. To identify genetic factors that may contribute to the tumorigenicity of B-cell lymphomas in SJL mice, tumor genomes were analyzed for mutations in cellular oncogenes. No rearrangements were detected by Southern hybridization analysis in tumors at the abl, myc, mbcl-2, Ha-ras, Ki-ras and raf loci. Indolent tumors were not rearranged at the myb oncogene, however alterations were detected in both myb alleles in RCS5. Northern hybridization analysis on RNA from in vivo-derived tumor preparations failed to detect any myb transcripts in RCS5. The loss of normal myb expression could directly contribute to the aggressive phenotype of RCS5. Alternatively, expression of the RCS5 myb allele may have contributed to early stages of tumor development. The possibilities that the observed myb mutations affect tumor aggressiveness and H-2Ds expression are discussed. PMID: 1886709 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 307: Biochem Int. 1991 Aug;24(6):1127-33. L-cell growth stimulation by a beta-casein peptide: the importance of its phosphorylation site for activity. Shimizu M, Kato M, Miwa K, Kaminogawa S. Department of Agricultural Chemistry, University of Tokyo, Japan. L-cell proliferation was markedly enhanced by addition to the medium of a synthetic peptide corresponding to residues 1-18 of human beta-casein. Experiments using several synthetic peptides of decreasing length demonstrated that L-S-S-S-E-E (residues 7-12), a major phosphorylation site in beta-casein, appeared to be important for the activity. The phosphorylated beta-casein peptide showed no activity. Recent findings have demonstrated that a similar sequence, S-E-E-E or S-D-D-E, is commonly present in many oncoproteins derived from nuclear oncogenes such as myc, myb and E1A, and plays an important role in transformation functions. The beta-casein peptide may affect mammalian cell proliferation through a modification of of the oncoprotein functions. PMID: 1781791 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 308: Oncogene. 1991 Aug;6(8):1397-407. Interaction of the v-and c-Myb proteins with regulatory sequences of the human c-myc gene. Zobel A, Kalkbrenner F, Guehmann S, Nawrath M, Vorbrueggen G, Moelling K. Max-Planck-Institut fuer Molekulare Genetik, Abt. Schuster, Berlin, Germany. Eight c-Myb-binding sites have been identified in the regulatory region of the human c-myc gene using gel retardation and DNAase I footprint assays with purified bacterially expressed full-length and carboxy-terminally truncated c-Myb proteins. These binding sites exhibit different affinities whereby strong binding correlates better with conservation of the palindromic sequences, AACXGTT or AACGTT, than the previously described consensus sequence. Flanking AT-rich sequences further increase the binding affinity. The c-Myb-binding sites are arranged in pairs consisting of one high- and one low-affinity binding site. Binding of the Myb proteins to these sites is non-cooperative. The v-Myb protein protects two nucleotides fewer than the c-Myb protein. Co-transfection of reporter CAT genes, containing upstream human c-myc sequences including exon 1, with c-Myb-expressing constructs resulted in positive transactivation, which was eightfold with full-length Myb and 14-fold with the truncated Myb. This result suggests that the Myb protein could participate in regulation of human c-myc gene expression. PMID: 1679531 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 309: Zhonghua Zhong Liu Za Zhi. 1991 Jul;13(4):261-4. [Expression of protooncogenes c-myb and c-myc during the hexamethylene bisacetamide (HMBA)-induced commitment to terminal differentiation of murine erythroleukemia cells] [Article in Chinese] Chen ZX. Jiangsu Institute of Hematology, Suzhou. Modulation of a number of protooncogene expression occurs during differentiation of eukaryotes. Changes in expression of c-myb and c-myc during the HMBA-induced terminal differentiation of murine erythroleukemia cells were characterized by an early decrease (within 4 hrs), followed by the recovery of c-myc mRNA by 10 hrs, and the retention of suppression of c-myb expression for the rest of the induction period. Two MELC variants were used to further define the relationship between the differentiation and the protooncogene expression. R1 was a MELC variant completely resistant to HMBA, and R1 (VCR), a vincristine resistant R1, became inducible by HMBA again. The cell differentiation and the c-myb and c-myc expression were determined on R1 or R1 (VCR) cultured with HMBA respectively. The results demonstrated that the c-myc mRNA increased and remained relatively high as the cells grew to a saturated density regardless of the induction of differentiation. The R1 (VCR) cultured with HMBA displayed an early decrease in c-myb mRNA and a subsequent suppression of its expression, while the R1 cultured with HMBA showed a stable level of c-myb mRNA. These results suggest that the c-myb expression, rather than c-myc expression, is closely related to the HMBA-induced terminal differentiation. PMID: 1806345 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 310: J Virol. 1991 Jul;65(7):3607-16. Acute myeloid leukemia induction by amphotropic murine retrovirus (4070A): clonal integrations involve c-myb in some but not all leukemias. Wolff L, Koller R, Davidson W. Laboratory of Genetics, National Cancer Institute, Bethesda, Maryland 20892. Amphotropic murine retrovirus 4070A was demonstrated to be highly leukemogenic when inoculated intravenously into adult DBA/2 mice that were undergoing an intense chronic inflammatory response, but was nonleukemogenic in the absence of inflammation. The virus-induced promoonocytic leukemias, designated AMPH-ML, are similar morphologically and in cell surface marker expression to monocytic leukemias, called MML and MF-ML, previously shown to be induced by Moloney murine leukemia virus and MF-3 virus (a recombinant between Friend murine leukemia virus and Moloney murine leukemia virus) and resemble certain mature acute monocytic leukemias in humans (AML subtype M5). Approximately two-thirds of the AMPH-MLs (subgroup I) were demonstrated to have alterations in the 5' end of the c-myb locus, an event which occurs in 100% of MML and MF-ML. Data indicate that proviral insertions in AMPH-ML subgroup I resulted in aberrant c-myb mRNA expression and truncation of its translation product at the amino terminus. Approximately one-third of the AMPH-MLs (subgroup II) had not undergone any DNA rearrangements at the c-myb locus. In addition, their transcripts and protein products were of normal size. These latter leukemias also had not undergone DNA rearrangements in c-myc, although retroviruses expressing myc have previously been shown to induce monocyte-macrophage tumors in mice undergoing a chronic inflammation. That subgroup II leukemias had at least one clonal viral insertion suggests that there may be other sites in the cellular genome that can be activated by insertional mutagenesis in these murine acute monocytic leukemias. PMID: 1645785 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 311: Cancer Lett. 1991 Jun 14;58(1-2):7-16. Separation of clonogenic and differentiated cell phenotypes of ovarian cancer cells (HOC-7) by discontinuous density gradient centrifugation. Grunt TW, Dittrich E, Somay C, Wagner T, Dittrich C. Department of Chemotherapy, University of Vienna, Austria. We isolated clonogenic cells from differentiated HOC-7 ovarian cancer cells. Both cell subsets were characterised in respect to morphology, growth behaviour, DNA content and expression of tumour-associated antigens and nuclear oncogenes. Ten cell fractions (Fr) were separated by centrifugation in a discontinuous density gradient (Fr 1 less than 1.037 g/ml to Fr 10 greater than 1.069 g/ml, steps 0.004 g/ml). Large adenoid cells containing vacuoles filled with neutral polysaccharides were concentrated in Fr 1-4. These cells were non-clonogenic in soft agar. The growth on solid substrate was highest in Fr 6 and 7, intermediate in Fr 2-5 and Fr 8-10 and lowest in Fr 1. The mean cloning efficiencies of the fractions in soft agar were highest in Fr 6 (8.1%) and lowest in Fr 2 and 3 (0.1%). Diploid and near tetraploid cell subsets were found with similar frequency in all fractions. Immunocytochemistry revealed 4-7% Ki-67 positive cells in Fr 1-6 and 12-20% in Fr 7-10. In Fr 3-10 greater than or equal to 79% of the cells expressed CA 125. Positivity for c-myc, c-myb and c-fos (greater than or equal to 74%) was not correlated with clonogenicity. In conclusion, differentiated cells (Fr 1-4) were separated from cells with higher growth rates (Fr 5-10). Clonogenic cells were enriched in Fr 6. These data indicate that discontinuous density gradient fractionation represents a useful method for separation of cells with different degrees of differentiation, growth potential and clonogenicity. PMID: 2049785 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 312: Oncogene. 1991 Jun;6(6):903-9. Suppression of c-myc and c-myb is tightly linked to terminal differentiation induced by IL6 or LIF and not growth inhibition in myeloid leukemia cells. Hoffman-Liebermann B, Liebermann DA. Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104. Cell proliferation and differentiation are intimately related processes where the proto-oncogenes c-myc and c-myb have been implicated to play a role. Previously, we have shown that both c-myc and c-myb were induced in normal myeloid precursors when the cells were stimulated for growth, were expressed in the autonomously proliferating myeloid leukemic M1 cell line and were rapidly suppressed in both normal and M1 cells following induction of terminal differentiation associated with growth arrest. In order to distinguish molecular events associated with terminal differentiation versus those due to growth inhibition, as well as to increase our understanding of the role of the proto-oncogenes c-myc and c-myb in both of these cellular processes, in this work we have studied the expression of c-myc and c-myb in M1 cells induced for growth inhibition associated with terminal differentiation (via treatment with the physiological inducers IL6 or leukemia inhibitory factor mean value of LIF), partial differentiation (using IL1 or LPS) or no detectable differentiation properties (using IFN beta or IFN gamma). We show that, for all the treatments used in this study, down regulation of the proto-oncogenes c-myc and c-myb occurred only when M1 cells were stimulated to undergo terminal differentiation. In addition, we transfected the M1 cell line with a vector containing the c-myc gene under control of the beta-actin promoter, so that c-myc was no longer down regulated by IL6 or LIF. Previously, we have shown that in the presence of the myeloid differentiation inducers IL6 or LIF, these M1myc cells were blocked at an intermediate stage of myeloid differentiation and continued to proliferate. In sharp contrast to their altered response to IL6 or LIF, M1myc cells were as responsive as the parental M1 cells to growth suppression by the different antiproliferative compounds which do not induce terminal differentiation. Thus, continued expression of c-myc had no effect on growth suppression induced by IL1, IFN beta, IFN gamma and LPS. Taken together, these results indicate that c-myc and c-myb down regulation is not necessary for growth suppression, but down regulation of c-myc is, and c-myb may be, essential for terminal differentiation. PMID: 1906157 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 313: Rinsho Byori. 1991 Jun;39(6):639-44. [Effects of long-term low dose radiation--relationship between chromosomal translocation and the cellular oncogenes] [Article in Japanese] Kumagai E, Tanaka R, Onomichi M, Sawada S. Department of Medical Technology, College of Medical Science, Kumamoto University. To clarify the late effects of long-term exposure to low doses of radiation, chromosomal aberrations in the lymphocytes of radiological technologists (RT) were analyzed by the trypsin G-banding method. Structural aberrations were identified in 384 (2.5%) of 15,442 cells analyzed from 53 RT as compared to 177 (1.6%) of 11,136 cells from 36 healthy controls. Most of structural aberrations in both groups was translocations, and this frequency was significantly higher in the RT than in the controls. Translocations of chromosomes, such as Nos. 1, 2, 7 and 14 in RT and Nos. 1, 3, 7 and 14 in controls, was observed in over 7% of the cells. 7/14 translocations were the most frequent reciprocal translocations in RT. However, the frequency of 7/14 translocations was not significantly different between the RT and controls. In these cases, most of the break points were localized in band 14q11-12 and 7q32-36. At the chromosomal sites which were related to the sites of ski, abl, myb, mos, myc, N-myc oncogenes, very low incidences of translocation were detected in RT. However, none of the RT demonstrated abnormal clones of cells with identical chromosomal aberrations. PMID: 1880940 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 314: 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] --------------------------------------------------------------- 315: J Immunol. 1991 Jun 1;146(11):3849-56. Production of IL-1 alpha by activated Th type 2 cells. Its role as an autocrine growth factor. Zubiaga AM, Munoz E, Huber BT. Department of Pathology, Tufts University School of Medicine, Boston, MA 02111. Autocrine growth of Th type 2 cells has been reported to be mediated by the lymphokine IL-4. In this report we present evidence that in addition to IL-4 Th2 cells also produce IL-1 alpha in its active form in the absence of APC. We have found that this cytokine is an autocrine growth factor, because proliferation of Th2 cells in response to several stimuli is inhibited by anti-IL-1 alpha or anti-IL-1R mAb, or by an IL-1 alpha antisense oligodeoxynucleotide. However, Th1 cells do not produce this cytokine. We have investigated the role of endogenous IL-1 alpha on the induction of c-myc and c-myb, two protooncogenes involved in T cell activation. Here we show that endogenous IL-1 alpha is involved in the activation of both protooncogenes. Our results suggest that a possible function of IL-1 alpha, and perhaps other growth factors, might be to sustain or amplify the initial second messengers derived through the TCR. The possible implications of this finding with respect to interactions between T cell subsets and B cells or macrophages are discussed. PMID: 1827818 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 316: Cancer. 1991 May 15;67(10):2594-8. Oncogene expression in the liver tissue of patients with nonneoplastic liver disease. Haritani H, Esumi M, Uchida T, Shikata T. First Department of Pathology, Nihon University School of Medicine, Tokyo, Japan. The expression of cellular oncogenes in nonneoplastic human liver tissue was examined to determine if there was a correlation between oncogene expression and physiologic regeneration in liver disease. Human liver tissue specimens from 70 patients with various histologic findings from almost normal to cirrhosis were examined (using northern blot analysis) for the expression of nine cellular oncogenes. With c-K-ras, four RNA bands (5.6-kilobase [kb], 2.1-kb, 1.5-kb, and 1.2-kb RNA species) were detected in all liver tissue examined. Expression of c-fos was also detected in a few samples examined when 50-micrograms samples of total RNA were applied. Other oncogenes such as H-ras, myc, erbB, raf, fms, fes, and myb were not detected. These results indicate that particular oncogene(s) may not be highly expressed during liver regeneration in human liver disease, or that populations of regenerating hepatocytes may be too small to show significant elevations of oncogene expression. The new finding of a constant expression of c-K-ras in human liver tissue suggests that it is linked to essential hepatocellular function rather than carcinogenesis. PMID: 2015559 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 317: Mol Cell Biol. 1991 May;11(5):2375-81. Interleukin-6- and leukemia inhibitory factor-induced terminal differentiation of myeloid leukemia cells is blocked at an intermediate stage by constitutive c-myc. Hoffman-Liebermann B, Liebermann DA. Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104-6059. Interleukin-6 (IL-6) and leukemia inhibitory factor (LIF), two multifunctional cytokines, recently have been identified as physiological inducers of hematopoietic cell differentiation which also induce terminal differentiation and growth arrest of the myeloblastic leukemic M1 cell line. In this work, it is shown that c-myc exhibited a unique pattern of expression upon induction of M1 terminal differentiation by LIF or IL-6, with an early transient increase followed by a decrease to control levels by 12 h and no detectable c-myc mRNA by 1 day; in contrast, c-myb expression was rapidly suppressed, with no detectable c-myb mRNA by 12 h. Vectors containing the c-myc gene under control of the beta-actin gene promoter were transfected into M1 cells to obtain M1myc cell lines which constitutively synthesized c-myc. Deregulated and continued expression of c-myc blocked terminal differentiation induced by IL-6 or LIF at an intermediate stage in the progression from immature blasts to mature macrophages, precisely at the point in time when c-myc is normally suppressed, leading to intermediate-stage myeloid cells which continued to proliferate in the absence of c-myb expression. PMID: 1901940 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 318: Kidney Int. 1991 May;39(5):946-53. Proto-oncogene expression in peripheral blood mononuclear cells in IgA nephropathy. Ebihara I, Nakamura T, Suzuki S, Tomino Y, Koide H. Department of Medicine, Juntendo University School of Medicine, Tokyo, Japan. We have investigated the expression of proto-oncogenes in mononuclear cells obtained from patients with IgA nephropathy using a RNA hybridization technique. Patients with IgA nephropathy expressed more c-myc, c-raf, c-fos, and c-jun proto-oncogene RNA than did normal controls. However, no significant expression of c-N-ras, c-mos or c-myb genes was found in the mononuclear cells of these patients. When the amount of urinary protein excretion was used as an indicator of disease activity (greater than 1 g/day), a positive correlation was found between c-myc, c-raf, c-fos, and c-jun expression and urinary protein excretion (P less than 0.01). The expression of these genes correlated also with the serum IgA concentration (P less than 0.01), IgA immune complex (P less than 0.01), and histopathological changes in renal tissues obtained from patients with IgA nephropathy (P less than 0.01). The results of this survey suggest that abnormally regulated proto-oncogene expression in mononuclear cells may play an important role in the progression of IgA nephropathy and may be useful as an indicator of disease activity and/or prognosis. PMID: 1712408 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 319: Am J Med Sci. 1991 Apr;301(4):238-45. Enhanced expression of oncogene-encoded mRNA in a rat model of colon cancer. Alexander RJ, Buxbaum JN, Raicht RF. Research Service, D.V.A. Medical Center, New York, New York 10010. We have studied the expression of oncogene-encoded mRNAs in a rat model of colon cancer. In this model, rats are intrarectally administered several low doses of the direct-acting carcinogen, N-methyl-N-nitrosourea (MNU). Tumors, predominantly adenomas, develop 5-7 months following administration of the carcinogen, and many of these progress to carcinomas. Upon assaying the steady-state levels of oncogene-encoded transcripts in normal rat colon, we found that fos and N-myc are highly expressed; H-ras, K-ras, myc, myb, and neu messages are present at lower levels; and N-ras, abl, and raf mRNAs are absent. When we compared transcript levels in rat tumors to those in normal colons from the same animal, we observed a 2-4 fold increase in both myc- and H-ras-encoded mRNAs and a 2-7 fold increase in myb message, but no change in expression of any of the 7 other genes. To test whether this increased expression is related to tumor production or is simply a result of the more rapid cellular turnover observed in tumor tissue, the level of oncogene-encoded transcripts was assayed in colonic mucosae of rats given two treatments known to enhance cell turnover and DNA synthesis in the colon. Neither acute application of MNU nor a diet containing 1% cholic acid caused any change in the level of oncogene-encoded mRNAs in rat colons, thus suggesting that the increased abundance of myc, myb, and H-ras messages in tumors is associated with tumor formation. The enhancement of expression of these genes in adenomas, as well as in carcinomas, further suggests that these alterations occur relatively early during the tumorigenic process. PMID: 2012108 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 320: Cancer Commun. 1991 Apr;3(4):119-26. Alteration of cellular oncogene expression in L1210 cells by a nitrosourea analog of thymidine. Zhang XK, Zucker ML, Huang DP, Lin TS, Prusoff WH, Chiu JF. Department of Biochemistry, University of Vermont College of Medicine, Burlington 05405. 3'[3-(2-Chloroethyl)-3'nitrosoureido]-3'-deoxythymidine (3'-CTNU), a chloroethylnitrosourea analog of thymidine, is a potent antineoplastic agent against murine leukemia L1210. In this study, we have examined the effects of 3'-CTNU on cellular oncogene (proto-oncogene) expression. We found that the expression of the c-myb proto-oncogene was dramatically enhanced in a concentration- and time-dependent manner by 3'-CTNU in murine leukemia L1210 cells, whereas the expression of the c-myc proto-oncogene was suppressed. The enhancement of c-myb gene expression was found to be cell type-specific and to involve an increase of the c-myb transcription rate rather than an alteration of c-myb gene structure or increased stability of c-myb mRNA. Further analysis demonstrated that the altered c-myb gene expression was largely due to the presence of 3'-amino-3'-deoxythymidine, a decomposition product of 3'-CNTU. The expression of five other proto-oncogenes was unaffected by 3'-CTNU treatment. Our study showed that an antineoplastic agent can increase or decrease the expression of proto-oncogenes. PMID: 1709036 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 321: J Natl Cancer Inst. 1991 Mar 20;83(6):405-16. Endometrial cancer: biochemical and clinical correlates. Gurpide E. Department of Obstetrics, Gynecology and Reproductive Science, Mount Sinai School of Medicine, New York, NY 10029. Some endometrial cancers and endometrial adenocarcinoma cell lines show amplified expression of proto-oncogenes (fos, fms, myc, myb, neu, and erb-B) and augmented production of growth factors (colony-stimulating factor 1, epidermal growth factor, transforming growth factor-alpha, and transforming growth factor beta) and epidermal growth factor receptor. Oncogene expression, the presence of estrogen and progesterone receptors, and the fraction of cells in S phase are useful biochemical prognostic indicators of clinical outcome, and markers recognized by monoclonal antibodies are available for use in following the clinical course of the disease and responses to treatment. In vivo and in vitro studies on normal and neoplastic tissues are providing evidence of paracrine influences on epithelial cell proliferation. Long-term administration of tamoxifen as adjuvant therapy for breast cancer has recently been found to increase the risk for development of endometrial cancer. Publication Types: Review Review, Tutorial PMID: 1999848 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 322: Cancer Res. 1991 Mar 15;51(6):1741-3. Interleukin 3-dependent proliferation of the human Mo-7e cell line is supported by discrete activation of late G1 genes. Avanzi GC, Porcu P, Brizzi MF, Ghigo D, Bosia A, Pegoraro L. Dipartimento di Scienze Biomediche ed Oncologia Umana, Universita degli studi di Torino, Italy. The hemopoietic growth factor interleukin 3 (IL-3) supports the survival and proliferation of multipotent and committed progenitor cells in vitro. To elucidate the molecular mechanisms triggered by IL-3 we studied the expression of cell cycle-related genes in a recently established human IL-3-dependent clone (M-07e). No changes in the level of expression of early (c-myc), mid (ornithine decarboxylase), or mid-late G1 (p53, c-myb) cell cycle genes were detected after restoration of IL-3 in deprived cells. The fact that only late G1-S-phase genes [proliferating cell nuclear antigen (PCNA) thymidine kinase (TK), histone H3] are modulated by IL-3 suggests that this factor may control human cell proliferation by acting at the G1-S boundary. PMID: 1998964 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 323: Blood. 1991 Mar 15;77(6):1181-90. Antisense myb inhibition of purified erythroid progenitors in development and differentiation is linked to cycling activity and expression of DNA polymerase alpha. Valtieri M, Venturelli D, Care A, Fossati C, Pelosi E, Labbaye C, Mattia G, Gewirtz AM, Calabretta B, Peschle C. Department of Hematology-Oncology, Istituto Superiore di Sanita, Rome, Italy. These studies aimed to determine the expression and functional role of c-myb in erythroid progenitors with different cycling activities. In the first series of experiments the erythroid burst-forming unit (BFU-E) and colony-forming unit (CFU-E) populations from adult peripheral blood (PB), bone marrow (BM), and embryonic-fetal liver (FL) were treated with either c-myb antisense oligomers or 3H-thymidine (3H-TdR). A direct correlation was always observed between the inhibitory effect of anti-myb oligomers and the level of cycling activity. Thus, the inhibitory effect of antisense c-myb on the number of BFU-E colonies was 28.3% +/- 15.8% in PB, 53.4% +/- 9.3% in BM, and 68.2% +/- 24.5% in FL. Both adult and embryonic CFU-E were markedly inhibited (73.2% +/- 10.4% and 74.2% +/- 12.7%). Using highly purified PB progenitors, we observed a similar pattern, although with slightly lower inhibitory effects. In the 3H-TdR suicide assay the killing index of BFU-E was 8.9% +/- 4.2% in PB, 29.4% +/- 6.5% in BM, and 40.1% +/- 9.6% in FL. The values for adult and embryonic CFU-E were 55.7% +/- 7.9% and 60.98% +/- 6.6%, respectively. We then investigated the kinetics of c-myb mRNA level during the erythroid differentiation of highly purified adult PB and FL BFU-E, as evaluated in liquid-phase culture by reverse transcription-polymerase chain reaction. Adult erythroid precursors showed a gradual increase of c-myb mRNA from day 4 through day 8 of culture and a sharp decrease at later times, whereas the expression of c-myb mRNA and protein in differentiation embryonic precursors peaked 2 days earlier. In both cases, c-myb mRNA level peaked at the CFU-E stage of differentiation. Finally, highly purified adult PB BFU-E were stimulated into cycling by a 3-day treatment with interleukin-3 in liquid phase: both the sensitivity to c-myb antisense oligomers and the 3H-TdR suicide index showed a gradual, strictly parallel increase. Under the same experimental conditions a progressive increase of the mRNA level of DNA polymerase alpha was observed. These observations suggest that in early erythroid differentiation c-myb activation is associated with the progression of progenitors into the S phase of the cell cycle, as well as to the synthesis of DNA polymerase alpha. PMID: 1705831 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 324: Int J Cell Cloning. 1991 Mar;9(2):123-33. Alteration of nuclear proto-oncogene expression by erythropoietin (Epo) in Epo-responsive murine cell lines. Tsuda H, Aso N, Sawada T, Hata H, Kawakita M, Mori KJ, Takatsuki K. Second Department of Internal Medicine, Kumamoto University Medical School, Japan. The signal transduction system of erythropoietin (Epo) and the accompanying molecular control mechanism of proliferation and differentiation of erythroid progenitors remains largely unknown. In this study, the effect of Epo on the expression of nuclear oncogenes was investigated in two murine cell lines which respond to the hormone in different ways: ELM-I-1 cells proliferate independently of Epo, but differentiate in response to the hormone, while the growth of DA-1ER cells is absolutely dependent on Epo or interleukin (IL) 3. The cell lines were stimulated with Epo or IL-3, and total RNA was extracted. Then expression of nuclear proto-oncogenes (c-myc, c-fos and c-myb) was analyzed by northern blotting. The change in c-fos expression observed during the first two h following stimulation with either stimulant were common to both cell lines; a rapid and temporary increment. Before stimulation, c-myc and c-myb were strongly expressed in both lines. No apparent change in c-myc expression was observed during the first two h of stimulation, while c-myb expression in ELM-I-1 cells was slightly reduced 1 h after stimulation with Epo but not with IL-3. Three days after stimulation with Epo, but not with IL-3, only ELM-I-1 produced hemoglobin and expressed a lower amount of c-myb mRNA. These data suggest the importance of c-fos in the early signaling system of Epo, and the involvement of c-myb in erythroid differentiation but not in proliferation. PMID: 2037810 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 325: Oncogene. 1991 Mar;6(3):455-60. Phorbol ester-mediated inhibition of growth and regulation of proto-oncogene expression in the human T cell leukemia line JURKAT. Makover D, Cuddy M, Yum S, Bradley K, Alpers J, Sukhatme V, Reed JC. Department of Internal Medicine, University of Pennsylvania, Philadelphia 19104. The expression and function of several proto-oncogenes were examined in a human acute T cell leukemia line, JURKAT, during phorbol ester-induced terminal differentiation. Treating JURKAT cells with the phorbol ester tetradecanoyl phorbol acetate (TPA) inhibited their proliferation and induced expression of the gene for the interleukin 2 receptor alpha chain (IL2R-alpha), consistent with previous reports. In unstimulated proliferating JURKAT cells, high levels of C-MYC, N-RAS, and BCL2 mRNAs were found that diminished rapidly following TPA-induced cessation of growth. In contrast, accumulation of mRNAs for the C-FOS, C-JUN, and EGR-1 genes increased markedly in TPA-treated cells and preceded the induction of IL2R-alpha mRNA. Expression of C-MYB, C-RAF-1, C-LCK, C-FYN, and C-FGR proto-oncogenes was relatively unchanged. To explore directly the function of two of these protooncogenes in regulating the growth of JURKAT T cells, we stably transferred C-MYC and BCL2 expression plasmids into these cells. Despite sustained expression of C-MYC, BCL2, or the combination of these protooncogenes, TPA continued to inhibit JURKAT cell growth and to induce IL2R expression. Thus, although C-MYC and BCL2 proto-oncogene expression correlated with proliferation in TPA-treated JURKAT cells, continuous over-expression of even the combination of these oncogenes was insufficient for abrogating the effects of TPA in these leukemic T cells. Because human lymphoid malignancies frequently contain chromosomal translocations that deregulate the expression of C-MYC and BCL2, our findings could have relevance for attempts to induce terminal differentiation of leukemic cells by in vitro exposure of patients' bone marrow cells to phorbol esters. PMID: 2011401 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 326: Am J Pathol. 1991 Mar;138(3):765-75. Cultured human atherosclerotic plaque smooth muscle cells retain transforming potential and display enhanced expression of the myc protooncogene. Parkes JL, Cardell RR, Hubbard FC Jr, Hubbard D, Meltzer A, Penn A. Institute of Environmental Medicine, New York University Medical Center, New York 10016. The proliferation of vascular smooth muscle cells (SMC) is critical to atherosclerotic plaque formation. The monoclonal hypothesis proposes that the stimulus for this SMC proliferation is a mutational event. Here we describe a procedure for growing human plaque smooth muscle cells (p-SMC) in culture. We show that p-SMCs derived from two patients differ from SMC cultured from normal vascular tissue in expression of the protooncogene myc. One p-SMC strain was extensively characterized; these diploid, karyotypically normal cells have a finite life span in culture. Ultrastructural examination revealed two populations, one with classic contractile SMC appearance, the other, modulated to a synthetic state. Northern blotting showed a 2- to 6-fold and a 6- to 11-fold enhanced expression of myc by p-SMC, compared to SMC derived from healthy human aorta (HA-SMC) and saphenous vein (HV-SMC), respectively. In contrast, the p-SMC and HV-SMC expressed similar levels of message for the genes N-myc, L-myc, Ha-ras, fos, sis, myb, LDL receptor, EGF receptor, IGF I receptor, IGF II, and HMG CoA reductase. Finally, although p-SMCs are not tumorigenic, DNA isolated from these cells is positive in the transfection-nude mouse tumor assay. Myc, however, does not appear to be the transforming gene because no newly introduced human myc gene was detected in the p-SMC-associated nude mouse tumor. Thus human atherosclerotic p-SMCs possess both an activated myc gene and a transforming gene that is retained throughout many cell passages. PMID: 2000945 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 327: J Clin Invest. 1991 Mar;87(3):940-8. Guanine ribonucleotide depletion inhibits T cell activation. Mechanism of action of the immunosuppressive drug mizoribine. Turka LA, Dayton J, Sinclair G, Thompson CB, Mitchell BS. Department of Medicine, University of Michigan, Ann Arbor 48109. The immunosuppressive drug, mizoribine, has been used to prevent rejection of organ allografts in humans and in animal models. Based on studies in cell lines, mizoribine has been postulated to be an inhibitor of inosine monophosphate (IMP) dehydrogenase (EC1.2.1.14), a pivotal enzyme in the formation of guanine ribonucleotides from IMP. To further characterize the mechanism of action of this drug, we studied the effect of mizoribine on human peripheral blood T cells stimulated with alloantigen, anti-CD3 MAb, or pharmacologic mitogens. Mizoribine (1-50 micrograms/ml) was able to inhibit T cell proliferation by 10-100% in a dose-dependent fashion to all stimuli tested. Measurements of purine ribonucleotide pools by HPLC showed that mizoribine led to a decrease in intracellular GTP levels, and that repletion of GTP reversed its antiproliferative effects. We also examined sequential events occurring after T cell stimulation. Early events in T cell activation, as assessed by steady-state mRNA levels of c-myc, IL-2, c-myb, histone, and cdc2 kinase, as well as surface IL-2 receptor expression, were unaffected. However, cell cycle analysis revealed decreased numbers of cells in S, G2, and M phases, and showed that the G1/S block was reversed with GTP repletion. These data indicate that mizoribine has an effect on T cell proliferation by a mechanism distinct from that of cyclosporine or corticosteroids, and therefore may be useful in combination immunosuppressive regimens. PMID: 1999502 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 328: Development. 1991 Mar;111(3):699-713. The relationship between cell proliferation and the transcription of the nuclear oncogenes c-myc, c-myb and c-ets-1 during feather morphogenesis in the chick embryo. Desbiens X, Queva C, Jaffredo T, Stehelin D, Vandenbunder B. Laboratoire de Biologie du Developpement, Universite des Sciences et Techniques de Lille Flandres-Artois, Villeneuve, d'Ascq, France. We have described the expression of three nuclear protooncogenes, c-myc, c-myb and c-ets-1 during feather morphogenesis in the chick embryo. In parallel with the expression patterns obtained by in situ hybridization, we have mapped the spatial distribution of S-phase cells by monitoring the incorporation of 5-bromodeoxyuridine. We do not detect c-myc or c-myb transcripts during the early stages when S-phase cells are scattered in the dermis and in the epidermis. Rather c-ets-1 transcripts are abundant in the dermal cells which divide and accumulate under the uniform epidermis. At the onset of the formation of the feather bud, cells within each rudiment cease DNA replicative activities and c-myc transcripts are detected both in the epidermis and in the underlying dermis. This expression precedes the reentry into the S phase. The transcription of c-myb, which has been previously tightly linked to hemopoietic cells is also detected in the developing skin. This expression is essentially located in proliferating epidermal cells on and after the beginning of feather outgrowth. As feather outgrowth proceeds, the distribution of c-myc and c-myb transcripts is restricted to the highly proliferating epidermis. In contrast c-ets-1 transcripts are never detected in the epidermis. During the later stages of skin morphogenesis, the transcription of c-ets-1 is restricted to the endothelial cells of blood vessels, as previously described. We suggest that the differential expression of these nuclear oncogenes reflects the activation of different mitotic controlling pathways during the development of the skin. PMID: 1879337 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 329: Plant Cell. 1991 Mar;3(3):317-25. C1- and R-dependent expression of the maize Bz1 gene requires sequences with homology to mammalian myb and myc binding sites. Roth BA, Goff SA, Klein TM, Fromm ME. Plant Gene Expression Center, United States Department of Agriculture/University of California, Berkeley, Albany 94710. Tissue-specific expression of the maize anthocyanin Bronze-1 (Bz1) gene is controlled by the products of several regulatory genes. These include C1 or Pl and R or B that share homology to the myb proto-oncogenes and myc-like genes, respectively. Bz1 expression in embryo tissues is dependent on C1 and an R-sc allele of R. Transient expression from mutated and deleted versions of the Bz1 promoter fused to a luciferase reporter gene was measured in C1, Rscm2 embryos after gene transfer by microprojectiles. This analysis revealed that the sequences between -76 base pairs (bp) and -45 bp and a 9-bp AT-rich block between -88 bp and -80 bp were critical for Bz1 expression. The -76 bp to -45 bp region includes two short sequences that are homologous to the consensus binding sites of the myb- and myc-like proteins. Site-specific mutations of these "myb" and "myc" sequences reduced Bz1 expression to 10% and 1% of normal, respectively. Additionally, a trimer of a 38-bp oligonucleotide containing these myb and myc sites increased the expression of a cauliflower mosaic virus 35S minimal promoter by 26-fold. This enhancement was dependent on both C1 and R. Because the sites critical for Bz1 expression are homologous to the myb and myc consensus binding sequences and the C1 and R proteins share homology with the myb and myc products, respectively, we propose that C1 and R interact with the Bz1 promoter at these sites. PMID: 1840914 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 330: Cancer Res. 1991 Feb 15;51(4):1202-9. Relationship of acivicin-induced monocytoid differentiation of human myeloid leukemia cells to acivicin-induced modulation of growth factor, cytokine, and protooncogene mRNA expression. Weinberg JB, Mason SN. VA Medical Center, Division of Hematology/Oncology, Durham, North Carolina 27705. We have previously noted that the glutamine antagonist acivicin (alpha S,5S-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid) induces monocytoid differentiation of freshly isolated human myeloid leukemia cells and HL-60 cells. This study was designed to determine the effects of acivicin on the levels of HL-60 cell mRNA transcripts of several cytokines, growth factors, and protooncogenes implicated in the control of hematopoietic cell proliferation and differentiation. Control HL-60 cells did not express mRNA for granulocyte-colony-stimulating factor, granulocyte-macrophage-colony-stimulating factor, interleukin 3, or interleukin 6, and acivicin or phorbol myristate acetate did not induce their expression. Phorbol myristate acetate reduced expression of c-myc, c-myb, and heat shock protein 70 and enhanced those of macrophage-colony-stimulating factor and c-fms. Acivicin caused a decreased expression of c-myc, and an increased expression of mRNA for interleukin 1 beta and tumor necrosis factor alpha (TNF-alpha). The drug also caused an initial increase in c-myb, followed by a subsequent decrease below baseline levels. Supernatants and lysates of acivicin-treated HL-60 cells contained increased levels of interleukin 1 beta. Both TNF-alpha and interleukin 1 beta have been shown previously to influence hematopoietic cell differentiation. In our experiments, exogenous interleukin 1 added to HL-60 cells did not induce differentiation, but the combination of interleukin 1 and TNF synergistically enhanced the process. Pretreatment of the cells with TNF enhanced their responsiveness to subsequent treatment with interleukin 1. Our results demonstrate that the glutamine antagonist acivicin modulates HL-60 cell expression of TNF-alpha, interleukin 1 beta, c-myc, and c-myb and suggest that interleukin 1 beta and TNF-alpha might (in an autocrine manner) cause the differentiation. PMID: 1997162 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 331: J Biol Chem. 1991 Feb 5;266(4):2009-12. Erythropoietin activates the receptor in both Rauscher and Friend murine erythroleukemia cells. Chern Y, Spangler R, Choi HS, Sytkowski AJ. Laboratory for Cell and Molecular Biology, New England Deaconess Hospital, Boston, Massachusetts 02215. Alterations in the expression of two proto-oncogenes, c-myb and c-myc, have been implicated in the differentiation of transformed erythroid cells induced by chemical inducers, such as dimethyl sulfoxide (Me2SO). In the present study, we compared the expression of c-myb and c-myc during erythropoietin (Epo) and Me2SO induction of Rauscher erythroleukemia cells, which differentiate in response to both inducers, and Friend erythroleukemia cells, in which Epo-induced differentiation is blocked. Our results demonstrate that Epo induces specific changes in expression of c-myb and c-myc in both Rauscher and Friend cells. Epo increases c-myc transcript, in contrast to a decreased caused Me2SO, indicating that the biphasic mode of c-myc regulation seen with Me2SO is not required for erythropoiesis. The Epo-induced changes in c-myb and c-myc do not require new protein synthesis, thus identifying these proto-oncogenes as early response genes for Epo. Both cell types also exhibit rapid changes in membrane protein phosphorylation in response to Epo. Since the signal pathway from Epo receptor activation to the nucleus appears equally functional in both Rauscher and Friend cells, the data suggest that the inability of Friend cells to differentiate in response to Epo is due to a block at a later step in the induction process. PMID: 1846607 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 332: Mol Cell Biol. 1991 Feb;11(2):731-6. Constitutively expressed c-myb abrogates the requirement for insulinlike growth factor 1 in 3T3 fibroblasts. Travali S, Reiss K, Ferber A, Petralia S, Mercer WE, Calabretta B, Baserga R. Department of Pathology, Temple University Medical School, Philadelphia, Pennsylvania 19140. The proto-oncogene c-myb, whose expression is usually limited to cells of the hematopoietic lineages, can be expressed in fibroblasts if placed under the control of a constitutive promoter, such as the simian virus SV40 early promoter. 3T3 cells carrying a constitutively expressed human c-myb were found to grow in 1% serum or in a serum-free, platelet-derived growth factor-supplemented medium, whereas the parent cell line, BALB/c 3T3, needed insulinlike growth factor 1 (IGF-1) in addition to platelet-derived growth factor for growth. myb-carrying cells, however, could not grow in platelet-poor plasma. In fibroblasts, therefore, a constitutively expressed c-myb can abrogate the requirement for platelet-poor plasma or IGF-1. When 3T3 cells constitutively expressed both c-myc and c-myb, they could grow in serum-free medium without added growth factors. The ability of c-myb to abrogate in fibroblasts the IGF-1 requirement seems to be due to its ability to induce overexpression of IGF-1, as indicated by an increase in steady-state levels of IGF-1 mRNA. These results have some important implications; for instance, they suggest a commonality of pathways for entry into S phase in different cell types and the possibility of a myb-like or myb-equivalent gene product of critical importance for entry of fibroblasts into S phase. PMID: 1990279 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 333: Leukemia. 1991 Feb;5(2):142-9. Childhood undifferentiated leukemia with early erythroid markers and c-myb duplication. Castaneda VL, Parmley RT, Saldivar VA, Cheah MS. Department of Pediatrics, University of Texas Health Science Center, San Antonio 78284-7810. Ultrastructural, flow cytometric, and molecular studies were performed on leukemia cells from bone marrow and pleural effusion of a 6-year-old boy diagnosed with undifferentiated (MO) leukemia, using routine histology and immunostains at diagnosis and relapse. Ultrastructurally, surface and/or intracellular ferritin particles were present on or in some blasts and the majority of blasts contained identifiable acid ferrocyanide reactive inorganic iron comparable to that seen in normal early erythroblasts. The cells lacked other evidence of differentiation, including diaminobenzidine-reactive or immunoreactive hemoglobin. Flow cytometric analysis of malignant cells showed a lack of lymphoid or myeloid markers. Anti-transferrin receptor antibody was positive on 93% of cells and antibody to glycophorin A reacted with 23% of cells. RNA blot analysis of leukemia cells with myeloperoxidase (MPO) showed an absence of appreciable levels of MPO mRNA. Chromosome analysis showed 51,XY, t(1;16)(p31;q24), +6, +10, +15, +19, +21. The oncogene c-myb, which is specifically expressed and regulated in hematopoietic cells and produces a DNA-binding protein responsible for myeloid differentiation, was found to be duplicated in the patient's tumor cells. Expression of c-jun, N-ras, c-myc, and p53 was normal. The data indicate that the malignant cells in this patient are of early erythroid lineage at diagnosis and relapse and that classification of cell lineage can be enhanced by ultrastructural Prussian blue staining. The failure of this otherwise undifferentiated leukemia to express or evolve into a myeloid phenotype is biologically and clinically distinct from previously described cases of erythroid and myeloid leukemia and may represent a previously unidentified phenotype which should be included in the spectrum of 'undifferentiated' childhood leukemia. Publication Types: Case Reports PMID: 1708434 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 334: Prog Clin Biol Res. 1991;366:151-6. Patterns of regulation of nuclear proto-oncogenes MYCN and MYB in retinoic acid treated neuroblastoma cells. Thiele CJ. Molecular Genetics Section, National Cancer Institute, Bethesda, MD 20892. PMID: 2068135 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 335: J Immunol. 1991 Jan 1;146(1):136-43. IL-1 signal transduction pathways. I. Two functional IL-1 receptors are expressed in T cells. Munoz E, Zubiaga AM, Sims JE, Huber BT. Department of Pathology, Tufts University School of Medicine, Boston, MA 02111. We have recently characterized a subline of the Th2 cell line D10.G4.1, D10A, which responds to exogenous IL-1 in the absence of cofactors. In this cell line IL-1 activates two distinct transmission signal pathways, one leading to increased levels of intracellular cAMP, and the other to the phosphorylation of an 80-kDa substrate of protein kinase C (PKC). To determine whether both pathways are activated upon occupancy of a single IL-1R, we used a mAb, M15, which blocks binding of IL-1 to the 80-kDa IL-1R, known to be expressed in Th2 cells. Whereas M15 was able to inhibit the accumulation of cAMP induced by IL-1, it had no effect on the IL-1-induced phosphorylation of the 80-kDa substrate of PKC or the c-fos mRNA expression. In addition, we show that IL-1 induces the expression of the two proto-oncogenes c-myb and c-myc through the 80-kDa IL-1R, and that this induction is PKC independent. The proliferation of D10A cells in response to IL-1 is blocked by M15, but is unaffected by H-7, a potent inhibitor of PKC. These results indicate that the IL-1-induced proliferation of D10A cells is independent of PKC. In addition, IL-1 induces c-fos mRNA expression in thymocytes but not in EL-4 cells. PMID: 1845804 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 336: Eur J Cancer. 1991;27(11):1466-71. Rational design of sequence-specific oncogene inhibitors based on antisense and antigene oligonucleotides. Helene C. Laboratoire de Biophysique, Museum National d'Histoire Naturelle, INSERM U.201-CNRS UA.481, Paris, France. Synthetic oligonucleotides can be used to control the expression of specific genes. When targeted to messenger RNAs, oligonucleotides inhibit translation (the antisense strategy). Oligonucleotides can also be targeted to specific sequences of the DNA double helix where they inhibit transcription (the antigene strategy). Both strategies can be applied to control the expression of oncogenes in tumour cells. The mRNAs of several oncogenes have been chosen as targets for antisense oligonucleotides (myc, myb, bc12, abl, ras...). Discrimination between the proto-oncogene and the oncogene can be achieved in the case of ras oncogenes where activation results from point mutations in the coding sequence. Regulatory sequences involved in controlling the transcription oncogenes can also be used as targets for antigene oligonucleotides (myc, ras). Publication Types: Review Review, Tutorial PMID: 1835863 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 337: Cold Spring Harb Symp Quant Biol. 1991;56:99-107. MYB and MYC in the cell cycle. Bishop JM, Eilers M, Katzen AL, Kornberg T, Ramsay G, Schirm S. Department of Microbiology and Immunology, University of California, San Francisco 94143. PMID: 1819523 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 338: Mol Carcinog. 1991;4(4):297-307. Isolation and partial characterization of a transformation-associated sequence from human nasopharyngeal carcinoma. Cao Y, Sun Y, Poirier S, Winterstein D, Hegamyer G, Seed J, Malin S, Colburn NH. Laboratory of Viral Carcinogenesis, National Cancer Institute, Frederick Cancer Research, Maryland 21702-1201. A transforming activity associated with Chinese nasopharyngeal carcinoma (NPC) cell line CNE2 DNA has been identified by transfer into nontransformed promotion-sensitive mouse JB6(P+) C141 cells. To clone this transformation-associated sequence, we carried out three cycles of transfection, followed by cloning of anchorage-independent transformants in soft agar. A tertiary CNE/JB6 clonal transfectant cell line 625 whose DNA showed transforming activity, as indicated in both soft-agar assay and nude-mice implantation, was used to make a genomic library in the vector lambda dash. Using the human repeated sequence Blur 8 to screen the library, we obtained 10 human Alu-positive clones. A cloned Alu-positive insert of 16 kbp, CNE 323, was characterized in detail. CNE 323 transferred moderate transforming activity when introduced into JB6 P+ cells and showed no homology to Ha-, Ki-, or N-ras genes; human promotion sensitivity genes; src, myb, jun, myc, fos, raf, or int-2 oncogenes; or epidermal growth factor receptor. The isolated CNE 323 DNA sequence appeared to preserve the genomic structure of the original sequence found in CNE2 cells and in nude mouse tumors induced by CNE2 cells or by CNE/JB6 transfectant cells, indicating that the cloned NPC sequence was activated during NPC carcinogenesis and not during transfection or construction of the library, and that the cloned sequence or a larger sequence of which it was part played a role in tumor formation. Finally, we identified a 1.3-kb mRNA that hybridizes to a subclone of the 16-kb NPC sequence in CNE2 cell poly (A)+ RNA. PMID: 1714741 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 339: Eur Arch Otorhinolaryngol. 1991;248(5):279-85. Proto-oncogene allelic variations in human squamous cell carcinomas of the larynx. Dolcetti R, Pelucchi S, Maestro R, Rizzo S, Pastore A, Boiocchi M. Division of Experimental Oncology I, Centro di Riferimento Oncologico, Aviano, Italy. Proto-oncogene restriction fragment length polymorphisms (RFLPs) were investigated in a group of 23 patients with squamous cell carcinomas of the larynx. The frequency of the rare 5 kb c-mos allele was significantly higher than that observed in control groups of patients with colorectal neoplasms or lymphoproliferative disorders. In addition, the 2 patients heterozygous at the c-mos locus (TC-8 and TC-10) were the only 2 of our series of develop multiple malignancies. Also, the 10 kb L-myc allele was remarkably more represented in patients with laryngeal carcinoma when compared to controls. These findings suggest that c-mos and L-myc RFLPs might be helpful in identifying those individuals who are at a higher risk of developing laryngeal carcinomas. Single allele amplification of L-myc, c-myb and c-mos proto-oncogenes, with no concomitant mRNA hyperexpression, were observed in 3 cases. The results obtained seem to rule out a direct pathogenetic role of these proto-oncogenes and suggest that the amplification of other closely linked genes, located on chromosomes 1, 6 and 8, respectively, may be causally associated with the development of these tumors. No allelic deletions at the c-myb locus were observed, whereas a loss of a c-Ha-ras-1 allele was demonstrated in one of the 11 heterozygous patients. Thus, the analysis of polymorphic proto-oncogenes in laryngeal carcinomas allowed us to identify a group of genetic abnormalities (chromosomes 1, 6 and 8 gene amplifications and c-Ha-ras-1 deletions) which may be involved in the development or progression of these tumors. PMID: 1679639 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 340: Int J Radiat Biol. 1991 Jan;59(1):15-29. Altered oncogenes in UV-transformed C3H 10T1/2 mouse cells: identification of mutated H-ras allele(s). Thomas JE, Guernsey DL. Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa City 52242. Ultraviolet (UV) light will transform mammalian cells in culture to a phenotype which is characteristic of in vivo neoplasia. The UV-transformed C3H 10T1/2 mouse cell lines, TU-2 and TU-3, were analysed to determine the molecular mechanisms which may account for their phenotype, and to determine the types of mutations induced by UV light. DNA-transfection assays indicated that the transformed phenotype of TU-2 could not be transferred to non-transformed recipient cells. Therefore, studies were initiated to determine the mutagenic effects of UV light with respect to cellular oncogenes. Northern blot analysis indicated that five of the oncogenes analysed (erb-A, erb-B, mos, myb, and N-ras) were not expressed at detectable levels. The steady-state mRNA levels of fos, K-ras, abl, sis, and src oncogenes were similar in the C3H 10T1/2 and TU-2 cells. The mRNA levels of three oncogenes, raf, myc and H-ras, were 1.5-2.0-fold greater in the TU-2 cells compared to C3H 10T1/2. Southern blot analysis of HpaII restriction digested TU-2 DNA indicated that the H-ras oncogene has undergone methylation changes. More extensive analyses of the H-ras locus in TU-2 demonstrated a deletion of the 3' end of the gene, that may involve two separate mutated alleles. This type of damage is consistent with the lesions associated with sister chromatid exchange. While the H-ras locus in the other UV-transformed line, TU-3, showed methylation changes, there were no large genetic mutations detected by Southern blot analysis. These results suggest that UV-irradiation in vitro induces endogenous DNA damage that includes methylation changes and large genomic alterations. Further analysis will be necessary to determine the extent to which each may be involved in cell transformation. PMID: 1671062 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 341: Sci China B. 1990 Dec;33(12):1459-65. Effects of lycobetaine on chromatin structure and activity of murine hepatoma cells. Liu J, Yang SL, Xu B. Shanghai Institute of Materia Medica, Chinese Academy of Sciences. The effects of lycobetaine (LBT) on DNA single strand break and chromatin conformation were examined by in-situ nick translation method. It was found that LBT did not cause DNA single strand break. After 2-h incubation of murine hepatoma cells with 1-50 micrograms/ml LBT in vitro, the chromatin transcription activity was inhibited gradually. This effect was time- and dose-dependent. Actinomycin D produced a similar effect; 10-hydroxycamptothecin not only caused DNA single strand break, but also altered chromatin conformation; homoharringtonine had no marked influence on either. By molecular hybridization technique, it was found that the effect of LBT on individual genes was somewhat different. After 2-h incubation of the cells with LBT, the sensitivities of c-myc, N-ras, and beta 2-microglobulin genes to DNase I were decreased from 75 +/- 6, 66 +/- 4, 70 +/- 8% to 28 +/- 8, 25 +/- 5, 28 +/- 7%, respectively, while that of c-myb and beta-globin genes (8 + 6%, 6 + 5%) did not change obviously. PMID: 2282145 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 342: Genes Dev. 1990 Dec;4(12B):2235-41. New light on Myc and Myb. Part II. Myb. Luscher B, Eisenman RN. Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104. Publication Types: Review Review, Tutorial PMID: 2279697 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 343: Genes Dev. 1990 Dec;4(12A):2025-35. New light on Myc and Myb. Part I. Myc. Luscher B, Eisenman RN. Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle Washington 98104. Publication Types: Review PMID: 2269425 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 344: Am Rev Respir Dis. 1990 Dec;142(6 Pt 2):S20-6. Gene amplification in human lung cancer. The myc family genes and other proto-oncogenes and growth factor genes. Bergh JC. Department of Oncology, University of Uppsala, Sweden. The development of human lung cancer may require multiple genetic deletions affecting a number of chromosomes, e.g., 1, 3, 11, 13, and 17. These genetic aberrations may induce the activation of proto-oncogenes (c-jun, ras, c-raf1) and the loss of tumor suppressor genes (p53). Some of the activated proto-oncogenes and tumor suppressor genes are more selectively expressed or absent in small-cell lung cancer (L-myc, c-myb, c-scr, Rb gene) or non-small-cell lung cancer (c-erbB-2, c-sis, c-fes). These genes may thus be of importance for selection of differentiation pathway. The c-myc oncogene is frequently amplified in small-cell lung cancer cell lines in a much higher frequency than in vivo. This indicates that c-myc seems to be related to tumor progression and a relatively late event in the lung cancer development. The uncontrolled production of multiple growth factors has been identified in human lung cancer cell lines. These factors can promote and inhibit the proliferation via paracrine and autocrine loops via specific receptors. The products from some of the activated proto-oncogenes (c-sis, c-erbB-2) are sequences homologous to a certain growth factor (PDGF) and a receptor (EGF) identified in lung cancer. The production and action of these growth factors may be of major importance for further activation of proto-oncogenes via intracellular signal transduction and specific oncogenic activation leading to further tumor progression. Publication Types: Review Review, Tutorial PMID: 2174659 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 345: Zhongguo Yi Xue Ke Xue Yuan Xue Bao. 1990 Dec;12(6):416-20. [The effect of heat shock on mRNA expression in human T lymphocytes] [Article in Chinese] Liu Z. Institute of Basic Medical Sciences, Beijing. Total mRNA was extracted from activated T lymphocytes and Jurkat cells with and without heat shock, and then used for alpha-32P-labeled 1st strand cDNA synthesis with reverse transcriptase. DNA restriction fragments or cloned vectors of five oncogenes (abl, myc, myb, fos, Ki-ras) and of IL-2, IL-2 receptor, T-cell receptor beta-chain and transferrin receptor were dotted onto nitrocellulose filters. Hybridization results showed that the expression of c-myc and TfR mRNA was much lower in heat-shocked cells than in their normal counterparts. However IL-2 and Ki-ras mRNA increased after heat shock. Possible explanations for the results are discussed. PMID: 2151259 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 346: J Immunol. 1990 Dec 1;145(11):3635-40. Inhibition by anti-HLA class II monoclonal antibodies of monoclonal antibody OKT3-induced T cell proliferation. Studies at the mRNA level. Racioppi L, Moscarella A, Ruggiero G, Manzo C, Ferrone S, Fontana S, Zappacosta S. Dipartimento di Biologia e Patologia Cellulare e Molecolare, Universita di Napoli, Italy. mAb to monomorphic determinants of HLA class II Ag have been shown to inhibit monocyte-dependent OKT3-induced T cell proliferation, indicating that MHC class II molecules play a regulatory role also in Ag nonrestricted, CD3-induced T cell proliferation. This effect involves several steps in the process of T cell activation and proliferation, including IL-1 beta, IL-6, and IL-2 secretion and IL-2R alpha expression. In the present study, we analyzed the effect of an anti-HLA class II mAb (Q5/6) on the mRNA expression of genes related to monocyte and T cell activation. mRNA levels for early (early c-myc, c-fos) and late (late c-myc, N-ras, c-myb) genes involved in T cell activation were determined as well as mRNA levels for IL-1 beta, IL-6, IFN-gamma, IL-2, and IL-2R alpha. The kinetics of mRNA induction for ICAM-1 was also investigated. The results show that in T lymphocytes the expression of c-fos and early c-myc mRNA was unaffected by mAb Q5/6, whereas the c-myb and N-ras mRNA levels were strongly diminished as well as those of IL-2, IL-2R alpha, and IFN-gamma mRNA. An early increase of ICAM-1 mRNA was partially inhibited. In monocytes, a marked reduction of IL-1 beta and IL-6 mRNA was found. It is concluded that the HLA class II determinant involved in the inhibition mechanism can be engaged in the control of IL-1 beta and IL-6 mRNA levels and constitute an accessory signal up-regulating IL-2 and IL-2R alpha gene activation, through a pathway not affecting c-myc and c-fos expression. PMID: 1978847 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 347: Science. 1990 Nov 9;250(4982):805-8. cdc2 gene expression at the G1 to S transition in human T lymphocytes. Furukawa Y, Piwnica-Worms H, Ernst TJ, Kanakura Y, Griffin JD. Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA 02115. The product of the cdc2 gene, designated p34cdc2, is a serine-threonine protein kinase that controls entry of eukaryotic cells into mitosis. Freshly isolated human T lymphocytes (G0 phase) were found to have very low amounts of p34cdc2 and cdc2 messenger RNA. Expression of cdc2 increased 18 to 24 hours after exposure of T cells to phytohemagglutinin, coincident with the G1 to S transition. Antisense oligodeoxynucleotides could reduce the increase in cdc2 expression and inhibited DNA synthesis, but had no effect on several early and mid-G1 events, including blastogenesis and expression of interleukin-2 receptors, transferrin receptors, c-myb, and c-myc. Induction of cdc2 required prior induction of c-myb and c-myc. These results suggest that cdc2 induction is part of an orderly sequence of events that occurs at the G1 to S transition in T cells. PMID: 2237430 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 348: Mol Cell Biol. 1990 Nov;10(11):5747-52. Functional analysis of c-Myb protein in T-lymphocytic cell lines shows that it trans-activates the c-myc promoter. Evans JL, Moore TL, Kuehl WM, Bender T, Ting JP. Lineberger Cancer Research Center, Department of Microbiology-Immunology, University of North Carolina, Chapel Hill 27599-7295. The function of c-Myb protein was revealed by transfecting an expression vector containing the entire c-Myb protein-coding sequence into the murine CTLL-2 T-cell line. Expressions of high levels of c-Myb protein did not alter the expression of several T-cell markers, c-fos mRNA expression, responses to interleukin-2, and growth characteristics of these cells. Interestingly, expression of the c-myc gene was drastically increased in this clone. Further, the c-myb expression plasmid, but not a frameshift mutant of c-myb, enhanced the expression of a hybrid construct of c-myc promoter linked to a reporter gene by 8- to 14-fold. These results demonstrate a role of c-Myb protein in c-myc gene expression. PMID: 2233716 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 349: J Invest Dermatol. 1990 Nov;95(5):571-5. Comparison of cellular protooncogene activation and transformation-related activity of human melanocytes and metastatic melanoma. Husain Z, FitzGerald GB, Wick MM. Laboratory of Molecular Dermatologic Oncology, Dana-Farber Cancer Institute, Boston, MA 02115. Two cell lines (NH and HM1), established from patients with metastatic melanomas, were evaluated for the presence of activated cellular protooncogenes. Northern blot analysis demonstrated increased expression of the c-myc gene (from 9 to 14 times) in NH and HM1 cell lines by densitometric comparison with human melanocyte cell lines. Analysis of the expression of 13 additional cellular protooncogenes revealed either no detectable levels (c-fms, c-abl, v-src, c-erb A1, c-erb B, v-mos, TGF beta, and c-myb) or unaltered expression levels (cH-ras, N-ras, c-fos, and c-sis) in normal human melanocytes and metastatic melanomas. Elevated expression of the c-myc gene was also detected in two long-term cultured melanoma cell lines (RPMI 7951 and SKMEL-30). Analysis of c-myc expression by in situ hybridization in HM1 cells showed that expression was not localized to a sub-population of cycling cells and all cells were overexpressing c-myc mRNA. Differences in relative abundance of c-myc transcripts suggests a relationship with the ability of DNA from these cell lines to efficiently transform NIH 3T3 cells and form colonies on soft agar. PMID: 2121834 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 350: Blood. 1990 Nov 1;76(9):1830-7. Amplified expression of three jun family members inhibits erythroleukemia differentiation. Prochownik EV, Smith MJ, Snyder K, Emeagwali D. Department of Pediatrics, University of Michigan School of Medicine, Ann Arbor. Several different proto-oncogenes have been shown to influence cellular differentiation. One of the most widely studied model systems has been the Friend murine erythroleukemia cell (F-MELC) line, which can be induced to undergo erythroid differentiation by a variety of chemical agents. Constitutive overexpression of either the c-myc or c-myb proto-oncogenes has been previously shown to inhibit F-MELC differentiation, whereas c-myc antisense sequences accelerate the process. To investigate the potential involvement of other proto-oncogenes and immediate early response genes in F-MELC differentiation, we studied the expression of the three known members of the jun family as well as another gene, egr-1, which, like the jun family members, is expressed as an immediate early response gene in growth factor-stimulated quiescent cells. All four genes were expressed in F-MELC, although the levels of expression and modes of regulation differed. Transfection with amplifiable c-jun, junB, or junD expression plasmids inhibited differentiation, whereas transfection with an egr-1 expression plasmid was without effect. These results indicate that jun family members play a role in mediating F-MELC differentiation. The known inhibitory effect of phorbol ester tumor promoters on F-MELC differentiation may be the result of their known stimulation of jun expression. PMID: 2121297 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 351: Cancer Genet Cytogenet. 1990 Oct 1;49(1):75-86. Double minute chromosomes and a homogeneously staining chromosome region in C3H10T1/2 murine cells transformed "in vitro" by proton radiation. Privitera E, Mosna G, Sala E, Spiga I, Gambaro F, Ghidoni A. Dipartimento di Genetica a di Biologia dei Microorganism, Universita di Milano, Italy. Four foci (type II or type III) of transformed cells, isolated from the murine line C3H10T1/2 after exposure to proton radiations, were expanded and cytogenetically examined. While the overall numerical chromosome distributions were similar, there were some differences between the various cell lines with regard to the presence and frequency of specific-marker chromosomes and to the colony-forming efficiency in soft-agarose medium. No association between any of these markers and the transformed phenotype could be established. However, in the line F4, derived from a type II focus, numerous double-minute chromosomes (DM) were observed after passage 22, and the phenomenon became more pronounced in the subclone C2. The finding of DMs in radiation-transformed cells is unusual. The DMs were observed in long-term subcultures, and in one of them they were partially replaced by a homogeneously staining chromosome region (HSR). DNAs from transformed cells of the line F4 and subclone C2 was digested with restriction enzymes and analyzed by Southern blotting with probes for seven oncogenes commonly amplified in cancer cells (c-myc, N-myc, N-ras, Ki-ras, Ha-ras, c-myb, c-abl) and with probes for the mouse MHC class I region. None of the regions tested was structurally altered or amplified in these transformed cells. The origin of the genetic material carried by DMs or homogeneously staining intrachromosomal regions (HSR) in cells of the line F4 and subclone C2, where it is believed to provide a selective advantage for in vitro growth, remains unknown. PMID: 2168806 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 352: Cell Mol Neurobiol. 1990 Sep;10(3):459-70. Different regulation of mid-size neurofilament and N-myc mRNA expression during neuroblastoma cell differentiation induced by retinoic acid. Di Martino D, Ponzoni M, Cornaglia-Ferraris P, Tonini GP. Pediatric Oncology Research Laboratory, Gaslini Children's Hospital, Genova, Italy. 1. Neuroblastoma (NB) is an unusual neuroectodermal tumor showing a high degree of spontaneous regression. NB cells can be induced to differentiate in vitro by various agents. Cell differentiation results in morphological changes characteristic of the mature neuronal phenotype, including outgrowth of neurite-like structures with several interconnections. 2. Recent experiments indicate that morphological differentiation of NB cells is associated with changes in expression of N-myc, c-myc, and c-myb oncogenes and synthesis of neurofilament proteins. However, little is known about the transcription of neurofilament genes during differentiation. 3. We have analyzed the expression of both the N-myc oncogene and mid-size neurofilament (NF) genes in the LAN-1 human NB cell line, cultured in the presence of retinoic acid (RA). Continuous treatment with RA induced morphological differentiation within 5-6 days. The transcription of N-myc was down-modulated within 24 hr of the initial exposure to RA. The mid-size NF mRNA was increased at this time. The expression of N-myc was not modified in serum-deprived LAN-1 cells, indicating that N-myc transcription is unaffected by the arrest of the cells in the G1 phase. 4. We conclude that new synthesis of mid-size NF mRNA and a decrease in N-myc transcription precede de novo formation of neurite-like processes and morphological cell differentiation of neuroblastoma cells. PMID: 2123747 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 353: Environ Health Perspect. 1990 Aug;88:187-91. Morphological, biochemical, and molecular biological characterization of a rat rhabdomyosarcoma cell line during differentiation induction in vitro. Gerharz CD, Doehmer J, Mayer H, Oesch F, Gabbert H. Department of Pathology, Johannes-Gutenberg University of Mainz, Federal Republic of Germany. BA-HAN-1C is a clonal rat rhabdomyosarcoma cell line consisting of proliferating mononuclear tumor cells, some of which spontaneously fuse to form terminally differentiated postmitotic myotubelike giant cells. Exposure to retinoic acid resulted in an inhibition of proliferation and a marked increase in cellular differentiation. The number of myotubelike giant cells significantly increased, and about 30% of the mononuclear tumor cells exhibited morphological features of rhabdomyogenic differentiation which were not observed in the mononuclear cells of untreated cultures. Morphological differentiation was paralleled by an increase in total creatine kinase activity as a biochemical marker of differentiation. These effects of retinoic acid were preceded by an increased expression of proto-oncogene raf and transient expression of proto-oncogene fos. The maximum level of fos expression was observed at 15 min and of raf at 12 hr after exposure to retinoic acid. No expression of the proto-oncogenes src, myb, myc, ros, mos, erbA, and erbB was detected. PMID: 2272313 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 354: Mol Cell Biol. 1990 Aug;10(8):3952-64. Enhanced translation and increased turnover of c-myc proteins occur during differentiation of murine erythroleukemia cells. Spotts GD, Hann SR. Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2175. To determine whether regulation of c-myc proteins occurs during the differentiation of murine erythroleukemia cells, we examined c-myc protein synthesis and accumulation throughout dimethyl sulfoxide (DMSO)- or hypoxanthine-induced differentiation. c-myc protein expression exhibited an overall biphasic reduction, with an initial concomitant decrease in c-myc RNA, protein synthesis, and protein accumulation early during the commitment phase. However, as the mRNA and protein levels recovered, c-myc protein synthesis levels dissociated from the levels of c-myc mRNA and protein accumulation. This dissociation appears to result from unusual translational and posttranslational regulation during differentiation. Translational enhancement was suggested by the observation that relatively high levels of c-myc proteins were synthesized from relatively moderate levels of c-myc RNA. This translational enhancement was not observed with c-myb. Under certain culture conditions, we also observed a change in the relative synthesis ratio of the two independently initiated c-myc proteins. Posttranslational regulation was evidenced by a dramatic postcommitment decrease in the accumulated c-myc protein levels despite relatively high levels of c-myc protein synthesis. This decrease corresponded with a twofold increase in the turnover of c-myc proteins. The consequence of this regulation was that the most substantial decrease in c-myc protein accumulation occurred during the postcommitment phase of differentiation. This result supports the hypothesis that the reduction in c-myc at relatively late times is most important for completion of murine erythroleukemia cell terminal differentiation. PMID: 2196440 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 355: Blood. 1990 Jul 15;76(2):298-301. Regulation of proto-oncogene and tumor necrosis factor gene expression by ethanol in HL-60 myeloid leukemia cells. Datta R, Sherman ML, Kufe DW. Laboratory of Clinical Pharmacology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115. Previous studies have shown that certain low molecular weight polar solvents downregulate c-myc gene expression and induce terminal differentiation of human HL-60 myeloid leukemia cells. We have examined the effects of ethanol on gene expression in this cell line. The results show that while ethanol induces a more differentiated phenotype, this agent has little effect on the self-renewal capacity of HL-60 cells. Ethanol treatment was also associated with a concentration-dependent and transient downregulation of c-myc transcripts. Similar effects were observed for c-myb mRNA levels. The results further show that ethanol exposure is associated with induction of tumor necrosis factor gene expression. These findings indicate that ethanol induces changes in specific gene expression during non-terminal differentiation of HL-60 cells. The clinical effects of this agent could thus be related to altered patterns of gene expression in hematopoietic or other cells. PMID: 2196091 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 356: Int J Cancer. 1990 Jul 15;46(1):106-12. Genotype markers and proto-oncogene analysis in the CD30-positive "malignant histiocytosis" DEL cell line with t(5;6)(q35;p21). Gogusev J, Barbey S, Nezelof C. College de France, Laboratoire de Medecine Experimentale, Paris. The DEL cell line isolated from a patient who died of malignant histiocytosis exhibits a reciprocal chromosomal translocation t(5;6)(5q35;6p21). The cells were analyzed for Ig(Jh), TCR beta-gene rearrangements and proto-oncogene expression pattern, using a panel of molecularly cloned probes that included c-fms, c-myc, c-myb, c-pim, c-fos, N-myc, c-sis, c-fgr as well as the virally derived probes v-ki-ras and v-src. Consistent levels of expression of c-fms, c-myc, c-myb, c-ki-ras and c-fgr were identified in cells from several in vitro passages as well as from the heterotransplanted tumors in nude mice. Transcripts homologous to the c-fos, c-src and c-sis were not observed. Southern blot study of DNA showed that the banding pattern of the screened proto-oncogenes was not altered. Furthermore, Southern blot analysis demonstrated monoallelic immunoglobulin heavy chain (IgJh) rearrangement but a normal germ-line configuration of the kappa light chain and TCR beta-genes. These results appear to imply that a T- or B-cell origin can be eliminated and that several activated proto-oncogenes, usually expressed in immature MPS cells (c-fms) and myeloblastic cells (c-fgr), may be implicated in the proliferative activity of the DEL cell line, the stem of which may be a primitive, ancestral myelomonocytic cell. PMID: 2163988 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 357: Int J Cell Cloning. 1990 Jul;8(4):267-76. Molecular regulation of human megakaryocyte development. Gewirtz AM, Calabretta B. Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania. Extracellular regulators of human megakaryocyte development are becoming better defined. How these regulators function at the subcellular and, in particular, the molecular levels remains almost completely unknown. The recent development of molecular micromethodologies such as in situ hybridization, the polymerase chain reaction, and the use of antisense oligodeoxynucleotides now make such studies possible in normal cells. We therefore examined the effect of several recombinant human hematopoietic growth factors and the maturation agonist phorbol myristate acetate on the expression of selected growth-regulated and maturation/function-related genes. We also examined the role of the c-myb proto-oncogene in regulating megakaryocyte proliferative activity and ploidy development. Our results demonstrate that growth factors have complex time and concentration effects on gene expression in morphologically recognizable human megakaryocytes. They also suggest that a more complete understanding of normal megakaryocyte development at the molecular level will soon be possible. PMID: 2205664 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 358: J Clin Endocrinol Metab. 1990 Jul;71(1):223-9. H-ras protooncogene mutations in human thyroid neoplasms. Namba H, Gutman RA, Matsuo K, Alvarez A, Fagin JA. Department of Medicine, Cedars-Sinai Medical Center, University of California School of Medicine, Los Angeles 90048. Structural alterations of protooncogene sequences may be involved in the pathogenesis of human neoplasms. We screened 54 thyroid tumors (36 benign and 18 malignant) for gene rearrangements of the protooncogenes c-myc, c-myb, c-fos, c-erb-B1, c-erb-B2, c-erb-A, N-ras, K-ras, and H-ras. Only mutations of H-ras were observed. None of the 15 colloid adenomas examined had detectable H-ras rearrangements. Of the remaining tumors, we observed mutations of H-ras in 4 benign and 4 malignant neoplasms. Gene amplification was found in 5 tumors. An aggressive recurrent papillary carcinoma had a marked amplification of one of the H-ras alleles. The amplified allele was truncated, in that the 3' variable tandem repeat was not a part of the amplification unit, and contained a codon 12 point mutation leading to a valine for glycine substitution. We also observed the association of low copy gene amplification with a codon 12 valine for glycine mutation in a follicular adenoma. Two tumors contained H-ras EcoRI polymorphisms not present in the DNA of normal thyroid from the same individuals, and one follicular carcinoma showed loss of an H-ras allele. Ras protooncogenes may become transforming by quantitative mutations, leading to increased expression, or qualitative mechanisms, through activating point mutations. Both of these appear to coexist in thyroid neoplasms, and it may be that a combination of both mechanisms is capable of inducing a more complete spectrum of neoplastic phenotypes. PMID: 2196280 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 359: Proc Natl Acad Sci U S A. 1990 Jul;87(14):5283-7. Differential regulation of interleukin 4 and interleukin 5 gene expression: a comparison of T-cell gene induction by anti-CD3 antibody or by exogenous lymphokines. Bohjanen PR, Okajima M, Hodes RJ. Howard Hughes Medical Institute, Bethesda, MD 20814. Murine T helper type 2 clones were stimulated with immobilized anti-CD3 antibody or with recombinant lymphokines to compare the expression of T-cell activation genes induced by these stimuli. Immobilized anti-CD3 antibody, recombinant interleukin 2 (IL-2), and recombinant interleukin 4 (IL-4) all induced proliferation of the T helper type 2 clones 10-5-17 and D10. Proliferation of these clones induced by anti-CD3 antibody was completely inhibited by cyclosporine A, whereas cyclosporine A had little effect on proliferation induced by recombinant IL-2 or recombinant IL-4. Both immobilized anti-CD3 antibody, and recombinant IL-2 induced the expression of the protooncogenes c-myc and c-myb. Immobilized anti-CD3 antibody also induced expression of the lymphokine genes IL-4, interleukin 5 (IL-5), and granulocyte-macrophage colony-stimulating factor. In contrast, recombinant IL-2 induced IL-5 mRNA expression but did not induce detectable expression of IL-4 or granulocyte-macrophage colony-stimulating factor mRNA. Likewise, recombinant IL-4 induced expression of IL-5 but not IL-4 mRNA. Thus, the IL-4 and IL-5 genes appear to be differentially regulated after stimulation with recombinant lymphokines. Effects of cyclosporine A and the protein synthesis inhibitors cycloheximide and anisomycin on IL-4 and IL-5 gene expression suggest that these genes are activated by different pathways after anti-CD3 stimulation. Cyclosporine A completely inhibited anti-CD3-induced expression of IL-4 mRNA but not of IL-5 mRNA, and protein-synthesis inhibitors completely inhibited induction of IL-5 mRNA but not of IL-4 mRNA. Together, our data show that T-cell receptor-mediated and lymphokine receptor-mediated signals induce different patterns of lymphokine gene expression and provide strong evidence that the IL-4 and IL-5 genes are differently regulated. PMID: 2142529 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 360: EMBO J. 1990 Jul;9(7):2179-84. A role for the adenovirus inducible E2F transcription factor in a proliferation dependent signal transduction pathway. Mudryj M, Hiebert SW, Nevins JR. Howard Hughes Medical Institute, Duke University Medical Center, Department of Microbiology and Immunology, Durham, NC 27710. Adenovirus E1A dependent trans-activation of transcription involves the utilization of cellular promoter specific transcription factors. One such factor termed E2F is important for the transcription of the viral E2 gene and appears to be a rate limiting component targeted during the trans-activation event. Since E2F is of cellular origin and likely to be involved in cellular gene control, we have identified E2F binding sites in cellular genes. Examples include the c-myc, c-myb and N-myc protoncogenes, the DHFR gene and the EGF receptor gene. The transcription of these genes is regulated by cell proliferation signals and each falls into the so-called immediate early class: genes that are activated independent of new protein synthesis. Because of these common properties of regulation, we have addressed the possible role of E2F in growth factor dependent activation of transcription. Expression of a c-myc promoter driven CAT gene, transfected into quiescent 3T3 cells, is stimulated by serum addition whereas an identical gene containing mutations in the E2F binding sites is not responsive. The DNA binding activity of E2F is increased 4-fold upon serum stimulation and the kinetics of activation parallel activation of c-myc transcription. Furthermore, this increase in E2F activity is independent of new protein synthesis indicating that serum stimulation results in an activation of a pre-existing factor. These results thus provide strong evidence linking E2F and proliferation dependent control of transcription. We also believe that the E2F transcription factor is the first example of a regulator of the class of immediate early genes that is slowly activated by stimulation of cell proliferation. PMID: 2141565 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 361: Curr Opin Cell Biol. 1990 Jun;2(3):502-8. The myb and myc nuclear oncogenes as transcriptional activators. Cole MD. Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey. Publication Types: Review Review, Tutorial PMID: 2198899 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 362: Rinsho Ketsueki. 1990 Jun;31(6):736-48. [Application of flow cytometry to the study of hematologic disorders: analysis of oncogene products] [Article in Japanese] Tsuchiya H. Department of Pediatrics, Kumamoto University Medical School. Flow cytometry (FCM) is a useful method for clinical research of oncogene products since it can analyze proteins quantitatively which are located at cell surfaces or inside of cells. Oncogene products are now under study by FCM not only as tumor markers but also as functioning proteins in carcinogenesis. The examples of oncogene products analyzed by FCM are ras, myc, p53, myb and fos; those of cell-proliferation-related proteins are Ki-67, PCNA and DNA polymerase alpha. In some diseases the relationship between these proteins and disease classification, stage, pathophysiology, or prognosis have been clarified. Using dual color FCM of H-ras p21 and DNA, we analyzed the expression of H-ras p21 in human multiple myeloma and leukemias and found that H-ras p21 levels in multiple myeloma strongly correlated to the prognosis of patients (p = 0.03). When AML cells were stimulated by adding G-CSF, it was found that many cells proliferated but some were dying. The percentage of dying cells was small in one AML case whose myeloblasts showed increased expression of H-ras p21 by G-CSF stimulation. Together with other papers reviewed, it is conceivable that H-ras p21 expression is related to cell proliferation and inhibition of cell autolysis. Thus FCM is useful in the classification of the role of oncogene products in carcinogenesis in clinical cases. PMID: 2145449 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 363: Biochem Biophys Res Commun. 1990 May 16;168(3):1149-56. Effect of erythroid differentiation factor on erythroid differentiation and proliferation of K-562 cells. Miyamoto Y, Kosaka M, Eto Y, Shibai H, Saito S. First Department of Internal Medicine, School of Medicine, University of Tokushima, Japan. The effects of erythroid differentiation factor (EDF) on the levels of zeta-globin and several proto-oncogene mRNAs and transferrin receptors (Tf-R) of K-562 cells were examined. EDF decreased Tf-R expression and increased the level of zeta-globin mRNA. The mRNA level of c-fos began to rise within 3 hours and continued to increase up to 72 hours, but the levels of c-myb and c-abl decreased to 23 and 19%, respectively, of their initial levels after 48 hours. In contrast, the mRNA levels of c-myc and c-fms decreased transiently, but recovered within 48 hours. The modulation of several proto-oncogene mRNA levels was observed much earlier than the differentiation induction and the growth inhibition of K-562 cells by EDF. PMID: 2189403 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 364: Dis Markers. 1990 May-Jun;8(3):117-24. Elevated c-myc messenger RNA in multiple myeloma cell lines. Fourney R, Palmer M, Ng A, Dietrich K, Belch A, Paterson M, Brox L. Department of Medicine, Cross Cancer Institute, Edmonton, Alberta, Canada. Oncogene analyses of four human myeloma cell lines provided no indication of gene amplification or rearrangement using DNA probes for the met, raf, abl, mos, erb B, Her-2-neu, fos, myb-7, fms, L-myc, sis, and myb-1 genes. However, a consistent elevation of up to 23-fold in the level of c-myc mRNA was observed in all of the cell lines studied. No restriction fragment length polymorphism (in exons one, two, or three) or c-myc gene amplification has as yet been demonstrated to account for the c-myc mRNA elevation. The c-myc mRNA has a half-life of 25 min which is comparable to that observed in other systems. The elevation in c-myc mRNA is further evidence for the role of the c-myc proto-oncogene in the pathogenesis of myeloma. PMID: 1980237 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 365: J Clin Invest. 1990 Apr;85(4):1072-84. Regulation of megakaryocyte phenotype in human erythroleukemia cells. Long MW, Heffner CH, Williams JL, Peters C, Prochownik EV. Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor 48109. Induction of human erythroleukemia (HEL) cells with nanomolar tumor-promoting phorbol myristate acetate (PMA) diesters results in the synchronous acquisition of multiple markers of the megakaryocyte phenotype. Induced cells markedly increase their content of cytoplasm and show features of morphological maturation. At the ultrastructural level, PMA-treated cells show increases in cytoplasm, nuclear lobulation and nucleolar content, and free ribosomes. Limited numbers of cells also express alpha-granules and nascent demarcation membrane systems. Functionally, PMA-stimulated HEL cells express increased amounts of the megakaryocyte/platelet proteins: glycoprotein IIb/IIIa, platelet factor 4, von Willebrand factor, glycoprotein Ib, and thrombospondin. No changes are observed in antigenic markers of the erythroid (glycophorin A) or macrophage lineages (MO-1 or MO-2). The increases in antigenic expression are rapid, reaching maximum levels within 3-4 d under serum-free conditions. Treatment with PMA also abruptly (within 1-2 d) inhibits cellular division in these cells. Washout studies indicate that phorbols exert their effect within 18-24 h, the approximate cell cycle time for these cells. Consistent with proliferative arrest, c-myc proto-oncogene transcripts begin to decline within 8 h of PMA treatment, although transcripts of c-myb are unaffected. Importantly, megakaryocyte differentiation is associated with endomitotic DNA synthesis (i.e., continued DNA synthesis in the absence of mitosis and cytokinesis), with HEL cells reaching a DNA content of 3-12 times that of unstimulated cells. Endomitosis is coordinately regulated with changes in antigenic expression and cell size such that those cells having the highest DNA content are the largest and also express the greatest levels of antigen. PMID: 2318965 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 366: Oncogene. 1990 Apr;5(4):511-7. Retinoic acid induces down-regulation of several growth factors and proto-oncogenes in a human embryonal cancer cell line. Miller WH Jr, Moy D, Li A, Grippo JF, Dmitrovsky E. Department of Medicine, Memorial Sloan-Kettering Cancer Center, Cornell University Medical College, New York, New York. The human teratocarcinoma cell NTERA-2 cl. D1 (NT2/D1) is a cloned embryonal cancer cell line that differentiates into a neuronal phenotype and other cellular lineages after treatment with retinoic acid (RA). We examined the regulated expression of growth factors and proto-oncogenes in NT2/D1 cells. We studied RNA levels after six days of RA treatment to assess gene expression coincident with observed morphologic differentiation. Three growth factors were markedly down-regulated following RA treatment: Hst-1/kFGF and TGF-alpha expression became undetectable by Northern analysis and bFGF expression was substantially reduced. Minimal decline was seen for c-myc, N-myc, c-fos, and c-myb. Increased expression with differentiation was seen for the human homeotic genes Hox 2.1 and Hox 2.2. Assay of RNA levels daily after one to six days of RA treatment showed that the growth factor down-regulation inversely correlated with the homeotic gene up-regulation. Nuclear run-on studies showed low transcriptional rates for these homeotic genes, Hst-1/kFGF, and TGF-alpha that did not measurably change with RA treatment. To explore whether these regulated genes in NT2/D1 play a role in human testicular cancer, we examined RNA levels in a panel of human germ cell cancer lines. Hst-1/kFGF and bFGF are commonly expressed in five of seven male germ cell cancer lines. These data show that specific proto-oncogenes and growth factors are down-regulated with RA treatment of the NT2/D1 cell and that some of these regulated genes are often expressed in human germ cell cancer lines. PMID: 2158037 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 367: Int J Dev Biol. 1990 Mar;34(1):61-8. Oncogenes and avian development. Dieterlen-Lievre F, Jaffredo T, Bachnou N, al Moustafa AE, Saule S. Institut d'Embryologie Cellulaire et Moleculaire du CNRS, Nogent sur Marne, France. In order to detect signs of oncogene activity and elucidate their possible role in avian ontogeny we implemented two different strategies. One was to detect either the protein product or messenger RNA in situ at various stages of development. The other was to try and disturb development with retroviruses carrying one or several oncogenes in their activated forms. Time- and tissue-specific expression of c-myc was apparently not related to particular phases of cell evolution, such as population amplification. Rather the presence of c-myc immunoreactive product at particular stages appeared to depend on cell types. c-myb and c-ets messenger RNAs were found expressed preferentially in the blood system, respectively in hemopoietic and differentiating endothelial cells. The developing embryo heart was found to be uniquely sensitive to the effect of retroviruses provided that two conditions were respected. The first was the injection of the virus or construct prior to E3.5. The second was the presence of the v-myc gene, whether alone or associated with one or several other v-onc. In such cases a large proportion (70%) of chick and all quail embryos developed multiple heart rhabdomyosarcomas within 10 days. In chickens the association of a second v-onc or of two others induced the formation of secondary tumors, whose type was determined by the nature of the other oncogene(s).(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 2168200 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 368: Cell Growth Differ. 1990 Mar;1(3):113-7. Transcriptional down-regulation of c-myc expression by protein synthesis-dependent and -independent pathways in a human T lymphoblastic tumor cell line. Bading H, Moelling K. Max-Planck-Institut fuer Molekulare Genetik, Berlin, Federal Republic of Germany. We show that in the human T lymphoblastic tumor cell line Molt4 c-myc mRNA and protein expression is down-regulated after exposure to dimethyl sulfoxide, to phorbol myristate acetate, or to the calcium ionophore A23187, which raises the intracellular calcium concentration. A block to RNA elongation is largely responsible for decreased c-myc transcription. Although negative regulation by dimethyl sulfoxide takes place even when protein synthesis is inhibited by cycloheximide, the phorbol myristate acetate effect is blocked to some extent only by cycloheximide. The calcium ionophore-induced c-myc suppression, however, strictly requires de novo protein synthesis. Therefore, two different negative regulatory pathways are involved in c-myc regulation: one which is independent and one which depends on de novo protein synthesis. The latter one appears to be mediated by a rapidly calcium-dependent induced gene product. PMID: 2127692 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 369: J Cell Physiol. 1990 Feb;142(2):261-7. Effects of dexamethasone on induction of monocytic differentiation in human U-937 cells by dimethylsulfoxide. Nakamura T, Kharbanda S, Spriggs D, Kufe D. Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115. The present studies demonstrate that dimethylsulfoxide (DMSO) treatment of human U-937 myelomonocytic leukemia cells is associated with induction of monocytic differentiation. The DMSO-induced U-937 monocytic phenotype was associated with 1) growth inhibition, 2) loss of clonogenic survival, 3) increases in alpha-naphthyl acetate esterase (NSE) staining, and 4) increases in cell surface expression of the monocyte marker Mac-1. DMSO treatment of U-937 cells was also associated with down-regulation of c-myc and c-myb gene expression as well as with increases in tumor necrosis factor (TNF) mRNA levels. The results further demonstrate that induction of U-937 monocytic differentiation by DMSO is accompanied by increases in phospholipase A2 activity. Moreover, this stimulation of phospholipase A2 was sensitive to dexamethasone. We therefore studied the effects of dexamethasone on DMSO-induced differentiation of U-937 cells. Although dexamethasone had no effect on growth inhibition or loss of clonogenic survival by DMSO, this glucocorticoid blocked increases in NSE staining and cell surface Mac-1 expression. Dexamethasone also had no effect on the down-regulation of c-myc and c-myb expression but blocked the reappearance of c-myb transcripts after 6 hr of DMSO treatment. Finally, dexamethasone inhibited DMSO-induced increases in TNF gene expression. Taken together, the results demonstrate that dexamethasone inhibits multiple characteristics, including the stimulation of phospholipase A2 activity, associated with DMSO-induced monocytic differentiation of U-937 cells. PMID: 2406276 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 370: J Clin Invest. 1990 Jan;85(1):55-61. Stage-related proliferative activity determines c-myb functional requirements during normal human hematopoiesis. Caracciolo D, Venturelli D, Valtieri M, Peschle C, Gewirtz AM, Calabretta B. Istituto di Medicina ed Oncologia Sperimentale, Sezione di Ematologia, Torino, Italy. To determine if MYB protein is preferentially required during specific stages of normal human hematopoiesis we incubated normal marrow mononuclear cells (MNC) with c-myb antisense oligodeoxynucleotides. Treated cells were cultured in semisolid medium under conditions designed to favor the growth of specific progenitor cell types. Compared with untreated controls, granulocyte-macrophage (GM) CFU-derived colonies decreased 77% when driven by recombinant human (rH) IL-3, and 85% when stimulated by rH GM colony-stimulating factor (CSF); erythroid burst-forming unit (BFU-E)- and CFU-E-derived colonies decreased 48 and 78%, respectively. In contrast, numbers of G-CSF-stimulated granulocyte colonies derived from antisense treated MNC were unchanged from controls, though the numbers of cells composing these colonies decreased approximately 90%. Similar results were obtained when MY10+ cells were exposed to c-myb antisense oligomers. When compared with untreated controls, numbers of CFU-GM and BFU-E colonies derived from MY10+ cells were unchanged, but the numbers of cells composing these colonies were reduced approximately 75 and greater than 90%, respectively, in comparison with controls. c-myc sense and antisense oligomers were without significant effect in these assays. Using the reverse transcription-polymerase chain reaction, c-myb mRNA was detected in developing hematopoietic cells on days 0-8. At day 14 c-myb expression was no longer detectable using this technique. These results suggest that c-myb is required for proliferation of intermediate-late myeloid and erythroid progenitors, but is less important for lineage commitment and early progenitor cell amplification. PMID: 2404028 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 371: Leuk Res. 1990;14(11-12):997-1006. Early protooncogene expression during hemin-induced differentiation of human erythroleukemic cells. Griffin MO, Nelson JC, Abraham NG. Department of Medicine, New York Medical College, Valhalla 10595. In situ hybridization was used to study the effects of hemin on the expression of the oncogenes c-myc, c-fos, and myb, and on the mRNA level of erythroid porphobilinogen deaminase (PBG-D) and alpha-globin in HEL cells during differentiation. The technique was effective in detecting changes in mRNA levels in small numbers of HEL cells. Hemin stimulation of HEL cells results in an early increase in myb and c-myc expression and a decrease in c-fos mRNA, while increased PBG-D and alpha-globin expression is not seen until 8 h after hemin treatment. Blast-like cells display expression of c-myc, alpha-globin and PBG-D, while the more differentiated cells give a positive response to both c-fos and myb. During HEL cell differentiation, the mechanism of hemin stimulation appears to be through the up regulation of myb and c-myc mRNA and down regulation of c-fos. The subsequent expression of PBG-D and alpha-globin may indicate that early increases in protooncogene expression are first required for the normal progression of erythropoiesis to occur. PMID: 2280614 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 372: Oncogene. 1990 Jan;5(1):85-95. Charge configurations in oncogene products and transforming proteins. Karlin S, Brendel V. Department of Mathematics, Stanford University, California 94305. Statistically significant charge clusters are of infrequent occurrence in all kinds of proteins. In the six standard classes of proto-oncogene products, all of the nuclear class contain a significant charge cluster and several, but not all, of the transmembrane class do, whereas significant charge clusters or patterns are not found in protooncogenes of primarily cytoplasmic location, nor in membrane-bound (src-like) proto-oncogenes, nor in those of the ras family. Among nuclear oncogene families, such as myc, jun, fos, myb, or ets-related, and among homologous proteins across species, the significant charge clusters are part of the most conserved region. These gene families generally have similar charge distributions embodying a significant charge cluster, not of an invariant sign, preceded by a substantial uncharged stretch of predominantly polar residues. The nuclear transforming proteins p53 and p68 also contain significant charge clusters together with long uncharged segments, suggestive of a modular structure of these proteins. The transmembrane oncogene c-mas contains a mixed charge cluster and c-fms displays an unusual (0, +)7 pattern, in both cases positioned within their intracellular activating domain. Distinctive charge configurations for excreted proto-oncogenes are of a mixed character. Possible functions, mechanisms, and associated experimental procedures for studying proteins with anomalous charge distributions are discussed. PMID: 2181379 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 373: Oncogene. 1990 Jan;5(1):131-5. Strong association between c-myb and oestrogen-receptor expression in human breast cancer. Guerin M, Sheng ZM, Andrieu N, Riou G. Laboratoire de Pharmacologie Clinique et Moleculaire, Institut Gustave Roussy, Villejuif, France. Previous articles have reported that the c-myb proto-oncogene was activated in various types of tumours of the hematopoietic system suggesting that this gene plays a role in the development of these malignancies. However no studies of the c-myb gene have as yet been performed in solid primary tumours. In the present study we have analysed in breast cancer the c-myb gene with the aim to determine its involvement in tumour progression. Expression of the c-myb oncogene was analysed from 169 carcinoma specimens obtained from untreated patients with non-inflammatory breast cancer (NBC) (112 patients) and inflammatory breast cancer (IBC) (57 patients). A 3.5 kb c-myb transcript band was detected in 108 (64%) tumours. c-myb expression was found to be associated with good prognostic factors (lowest histopathologic grade (P = 0.01), oestrogen and progesterone receptor status (P less than 10(-4)) and pS2 gene expression (P less than 10(-4)) and negatively correlated with breast cancers of poorer prognosis, namely IBC (P = 0.03) and NBC with multiple involved nodes (P = 0.15). Other genes (c-myc, c-erbB2, c-fos and epidermal growth factor receptor) were also studied. The c-myb gene expression was found to be inversely correlated (P less than 0.03) with only c-erbB2 overexpression in NBC. When data were analysed with a logistic regression model using a stepwise procedure, c-myb expression was found to be associated only with the oestrogen receptor status (P less than 10(-4)). In conclusion, our data indicate that analysis of c-myb expression in breast cancer could allow the characterization of a new class of oestrogen-dependent tumours. PMID: 2181374 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 374: Arch Geschwulstforsch. 1990;60(2):89-96. Induction of leukemia in chicken by bovine leukemia virus due to insertional mutagenesis. Altanerova V, Ban J, Kettmann R, Altaner C. Department of Molecular Virology, Cancer Research Institute, Slovak Academy of Sciences, Bratislava, Czechoslovakia. Bovine leukemia virus (BLV) was inoculated into one-day-old chickens. In a small part of inoculated chickens leukemia developed during observation period of one year. Out of 88 birds inoculated, only 4 developed histopathologically verified leukemia. The induced leukemia was characterized by enlarged liver and spleen. The organs were infiltrated with leukemic cells. The DNAs of body organs of inoculated chickens were analysed by Southern blot hybridization for the presence of BLV specific sequences. Out of 9 suspicious chickens tested in 6 birds the BLV was found to be integrated into host DNA either as a complete viral genome or as a part corresponding to its 3'-end. The leukemic cells were monoclonal as regard to the integration site of the BLV provirus. Neither the expression of BLV provirus in chicken leukemic cells nor the antibody response to BLV antigens in inoculated birds was detected. The rearrangements and amplification of erb-B and myb loci of protooncogenes in leukemic cells was detected. There were no changes in loci of following protooncogenes: myc, sis, fes, fps, erb A, src and yes. All obtained data taken together suggest that the BLV induced leukemia in chickens is caused by insertional mutagenesis. PMID: 2160229 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 375: Eur J Cancer. 1990;26(6):733-7. Differential expression of the oncoproteins c-myc and c-myb in human lymphoproliferative disorders. Siegert W, Beutler C, Langmach K, Keitel C, Schmidt CA. Medizinische Klinik und Poliklinik, Universitatsklinikum Rudolf Virchow, Berlin, F.R.G. Altered regulation of oncogene expression has been described in a variety of hematopoietic malignancies. In this study we analyzed the protein level of c-myc and c-myb in 15 established cell lines derived from lymphopoietic disorders and in 45 samples from patients with acute or chronic lymphatic leukemias. Oncoproteins were assayed by radioimmuno-precipitation with polyclonal rabbit antibodies. In B-cell derived lines, such as Burkitt lymphoma and plasmocytoma lines, we found high amounts of c-myc and no or low amounts of c-myb. In contrast, all T-cell-derived lines revealed high levels of c-myb. In addition, T-lymphoma cell lines of low malignancy also exhibited high levels of c-myc, while T-cell lines of high malignancy (acute T-lymphoblastic leukemias) exhibited moderate levels of c-myc. Of the 45 patient samples analyzed, only three (one B-prolymphocytic and two acute T-lymphoblastic leukemias) contained detectable amounts of myc or myb protein. Corresponding to the results found in established cell lines, the B-cell sample revealed a high level of c-myc but no c-myb, while the T-cell samples revealed high levels of c-myb and no or low levels of c-myc. We therefore conclude that the predominance of c-myc or c-myb expression in malignant lymphoproliferative disorders may be associated to the B-cell or T-cell lineage, respectively. Further, regarding the T-cell lines, there is a possible correlation between cell maturation and the level of c-myc found together with a consistently elevated c-myb. PMID: 2144164 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 376: Eur J Cancer. 1990;26(6):694-8. Erratum in: Eur J Cancer 1990;26(9):1002. Proto-oncogene expression in differentiating and non-differentiating chronic myelogenous leukaemia cells. Wang ZQ, Yin MY, Xie XX, Yang PM, Sato H, Mayers G, Riobowal C, Preisler HD. University of Cincinnati Medical Center, Ohio. Despite the profound differences between the chronic and blastic phases of chronic myelogenous leukaemia, no differences between chronic and blastic phase cells have been described at the molecular level. Differences have been found in the levels of expression of c-myc, c-myb and p53, which fell when chronic phase cells were cultured, while the levels of expression of the genes were stable when blastic crisis cells were cultured. In contrast c-fms expression increased and MRS expression decreased after culture of chronic or blastic phase cells. The data suggest that the regulation of expression of some genes in blastic crisis cells is unaltered while that of others is disrupted. It is not known whether the failure of c-myc, c-myb and p53 expression to fall during the culture of blastic phase cells is the cause of or a reflection of the failure of these cells to differentiate. PMID: 2144156 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 377: Int J Cell Cloning. 1990 Jan;8 Suppl 1:130-46. Phenotypes and mechanisms in the transformation of hematopoietic cells. Ihle JN, Morishita K, Bartholomew C, Matsugi T, Askew D. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105. Interleukin 3 (IL-3) is a growth factor that supports the proliferation of early hematopoietic stem cells, as well as cells that are committed to a variety of the myeloid lineages. The mechanisms by which IL-3 functions have been studied through the use of a series of IL-3-dependent cell lines isolated from myeloid leukemias or long-term bone marrow cultures. A variety of studies have implicated tyrosine phosphorylation in IL-3 signal transduction. One of the substrates of phosphorylation is a 140 kDa, IL-3-binding protein that is speculated to be the biologically relevant IL-3 receptor. IL-3, through tyrosine phosphorylation, supports viability and growth through the regulation of transcription of a series of genes including c-myc and c-pim-1. The c-myc gene contributes to viability, in part, by regulating the transcription of the ornithine decarboxylase gene. The role of growth factors in differentiation is less clear. By studying IL-3-dependent myeloid leukemia cell lines, two genes have been identified whose altered expression is associated with blocking the ability of the cells to differentiate. The c-myb gene is a nuclear DNA binding protein that has been implicated in myeloid transformation in a number of systems. The Evi-1 gene is a novel gene of the zinc finger family of transcriptional activators. Possible mechanisms by which these genes interfere with normal differentiation are discussed. Publication Types: Review Review, Tutorial PMID: 2109024 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 378: Microbiol Immunol. 1990;34(11):937-52. Elevated expression of proto-oncogenes during interleukin-5-induced growth and differentiation of murine B lineage cells. Migita M, Yamaguchi N, Katoh S, Mita S, Matsumoto R, Sonoda E, Tsuchiya H, Matsuda I, Tominaga A, Takatsu K. Department of Biology, Kumamoto University Medical School. Interleukin 5 (IL-5), a lymphokine produced by helper T cells, is involved in the regulation of growth and differentiation of B cells and other hematopoietic cells. To elucidate IL-5-mediated intracellular mechanisms, we have established IL-5-dependent and -independent murine early B cell lines, J6 and MJ88-1, respectively, and examined the effect of IL-5 on the expression of proto-oncogenes during proliferation. Two- to 3.5-fold increases in the levels of c-myb, c-myc, c-fos, and c-fms mRNA were observed in J6 cells, compared with those in MJ88-1 cells. Further, a role of IL-5 in the proto-oncogene expression during differentiation was examined by using thymidine-treated murine B-cell chronic leukemia BCL1-B20 cells with growth arrest. After 4-day culture, the amount of IgM secreted from BCL1-B20 cells was augmented 4-6 fold in the presence of IL-5. Although expression of c-myb, c-fos, and c-fms mRNA did not change, only c-myc mRNA expression was elevated within 30 min of stimulation with IL-5 and reached a maximal level by 1 hr. Addition of phorbol 12-myristate 13-acetate (PMA) or IL-4 to the culture of BCL1-B20 cells inhibited both the IL-5-mediated augmentation of IgM secretion and the elevated expression of c-myc mRNA. These findings suggest that the IL-5 signal may be associated with the up-regulation of c-myc expression. PMID: 2090920 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 379: Cancer Invest. 1990;8(6):613-7. Chromosomal translocation t(1;22) and sis oncogene variant with gene amplification in a case of atypical malignant lymphoma. Tanaka T, Takahashi K, Miyachi Y, Imamura S. Department of Dermatology, Faculty of Medicine, Kyoto University, Japan. sis Oncogene amplification and PstI restriction enzyme variant were found in a patient of atypical malignant lymphoma with chromosomal translocation t(1;22). A diagnosis of atypical malignant lymphoma was made because dual rearrangements of both beta chain of T-cell receptor gene and heavy and kappa chains of immunoglobulin genes were observed by DNA analysis extracted from the lymph node. Amplification of sis was estimated to be about fivefold by dot blot. BamHI and EcoRI digested DNA hybridized with sis probe from blood and lymph nodes revealed identical bands. Lymph node DNA digested with PstI showed an extra band when compared with DNA samples extracted from peripheral blood. Other oncogenes, such as myb, abl, and myc showed no variant or amplification. These findings suggest that sis is abnormally rearranged in this lymphoma. One possible role of genes on chromosome 22, including sis oncogene, in the pathogenesis of this atypical malignant lymphoma is discussed. Publication Types: Case Reports PMID: 1981333 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 380: Leuk Res. 1990;14(6):549-58. A coordinated proto-oncogene expression characterizes MCF 247 murine leukemia virus-induced T-cell lymphomas irrespectively of proviral insertion affecting myc loci. Boiocchi M, Dolcetti R, Maestro R, Feriotto G, Rizzo S, De Re V, Sonego F. Experimental Oncology I, Centro di Riferimento Oncologico, Aviano, Italy. Proto-oncogene transcriptional activation was analyzed in a group of MCF 247 MuLv-induced T-cell lymphomas to identify transformation-specific gene activations and determine whether the proviral insertion near a myc gene could promote a peculiar mechanism of transformation through a differential proto-oncogene expression pattern. Of the six lymphomas analyzed, three showed the MCF 247 provirus integrated within the N-myc locus, one carried the provirus integrated near c-myc, whereas for the remaining two, no evidence of proviral integrations in any of the known myc loci was obtained. Independently of the integrative events, the pattern of proto-oncogene expression was almost identical in all six lymphomas. These findings seem to rule out the existence of a peculiar pathway of transformation associated with the proviral insertion near a myc locus. Moreover, the transcription pattern observed was qualitatively identical to that displayed by normal thymocytes; only quantitative differences in c- or N-myc, c-myb and Ha-ras were observed. These results suggest that the T-cell proto-oncogene activation program is not qualitatively affected by the transforming event(s). PMID: 1695700 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 381: J Cancer Res Clin Oncol. 1990;116(1):29-37. Different pattern of expression of cellular oncogenes in human non-small-cell lung cancer cell lines. Kiefer PE, Wegmann B, Bacher M, Erbil C, Heidtmann H, Havemann K. Philipps-University Marburg/Department of Internal Medicine, Federal Republic of Germany. Altered and deregulated cellular oncogenes were found in many human solid tumors. Except for a few types of tumors that consistently exhibited specific altered proto-oncogenes, the majority of tumors are associated with a number of transcriptionally activated cellular oncogenes. In the heterologous group of non-small-cell lung cancer (NSCLC), nothing about a specific pattern of proto-oncogene expression is known. Therefore, we investigated the expression of a panel of cellular oncogenes in NSCLC cell lines. DNA and RNA from 11 established NSCLC cell lines (4 adenocarcinoma cell lines, 3 squamous cell carcinoma cell lines, 3 large-cell carcinoma cell lines and 1 mesothelioma cell line) were isolated and analysed using the Southern, dot blot and Northern hybridization technique. c-myc RNA expression was found in all NSCLC cell line, L-myc expression only in 1 adenocarcinoma cell line, N-myc and c-myb expression in none of the 11 cell lines examined. No c-myc amplification could be detected in the DNAs. v-sis-related mRNA was observed in 5/11 cell lines without association to a specific NSCLC subtype. v-src-related mRNA, found in all tested cells, exhibited increased levels in 1 adenocarcinoma cell line (A-549) compared to the other cell lines. Binding sites for epidermal growth factor (EGF) had been described previously in NSCL, therefore we found erbB homologue transcripts coding for the EGF receptor in all NSCLC cell lines. Also, c-raf1-, N-ras-, Ki-ras-, and H-ras-related RNA expression was observed in all lines. We conclude that L-myc, N-myc, and c-myb expression does occur less frequently in NSCLC than in SCLC. Also amplification does not appear to be an important mechanism by which the c-myc proto-oncogene is activated in NSCLC. A specific pattern of oncogene expression could not be detected in NSCLC cells; each cell line examined showed its own pattern. However, transcriptional activation of a proto-oncogene like erbB, ras, raf, src, and c-myc, which are all involved in the progression pathway of EGF, may be a common feature of NSCLC. PMID: 1690210 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 382: Cancer Res. 1989 Dec 15;49(24 Pt 1):6911-6. c-myc and c-myb oncoproteins during induced maturation of myeloid and erythroid human leukemic cell lines. Pedrazzoli P, Bains MA, Watson R, Fisher J, Hoy TG, Jacobs A. Department of Haematology, University of Wales College of Medicine, Cardiff, United Kingdom. c-myc and c-myb mRNAs have been found to be tightly regulated during hemopoietic differentiation. We have studied nuclear c-myc and c-myb oncoproteins through the cell cycle, during macrophage, granulocyte, erythroid, and megakaryocytic differentiation of KG1, HL60, and HEL cells. p62c-myc and p75c-myb content of propidium iodide-stained nuclei was quantitated by flow cytometry using fluoresceinated antibodies CT14-G4 and MB4.3, respectively. In uninduced cells p62c-myc content is highest in HL60, followed by HEL, then KG1, while p75c-myb is highest in HEL, followed by HL60 and KG1. All lines showed a less than 2-fold increment in both oncoproteins over the cell cycle. Macrophage induction of KG1 and HL60 resulted in early increase in both oncoproteins, followed by a decline to less than starting values by 48 h, concurrent with a reduction of S phase cells and the appearance of adherent alpha-naphthyl acetate esterase-positive cells. p62c-myc changes were more pronounced in HL60 and p75c-myb changes in KG1. Different patterns of oncoprotein expression were found when different inducing agents were used for granulocyte differentiation of HL60. Under all conditions, however, both oncoproteins declined to basal levels before granulocyte maturity. Hemin-induced erythroid differentiation of HEL to hemoglobin-containing cells resulted in biphasic p62c-myc and p75c-myb kinetics. In contrast, dimethyl sulfoxide-induced megakaryocytic differentiation of HEL was accompanied by an early and steady decline in both oncoproteins. Despite considerable reduction in oncoprotein levels, HEL cells were still actively cycling at 120 h. It appears that c-myc and c-myb proteins decline with differentiation, well before proliferation ceases in some lineages. The kinetics of the decline differ between the two oncogenes and vary with the lineage induced and the nature of the inducing agent used. The cell cycle distribution of the oncoproteins does not change during maturation. These data suggest disparate roles for c-myc versus c-myb during hemopoietic differentiation and the existence of multiple signal transduction pathways for down-regulation of these genes. PMID: 2684403 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 383: Cancer. 1989 Dec 1;64(11):2243-9. Establishment of a human malignant meningioma cell line with amplified c-myc oncogene. Tanaka K, Sato C, Maeda Y, Koike M, Matsutani M, Yamada K, Miyaki M. Department of Biochemistry, Tokyo Metropolitan Institute of Medical Science, Japan. A new cell line (KT21-MG1) has been established from a human malignant meningioma transplanted into nude mice. The cultured cells showed epithelial cell-like morphology and were positive immunohistochemically for vimentin as the original tumor. They have been grown continuously in vitro for more than 2 years. The population doubling time was about 24 hours at the 30th passage. The cells are capable of proliferating in soft agar medium and produced tumors in nude mice, the histologies of which were similar to the original patient-derived tumor. Analysis of cellular oncogenes showed that myc and fps were amplified approximately tenfold and threefold, respectively, in this cell line, whereas N-myc, L-myc, N-ras, K-ras, H-ras, abl, erbB2, Blym, src, raf-1, myb, and sis were not changed significantly. The amplification of myc was accompanied by an enhanced expression. Chromosome studies of cultured cells showed the monosomy of chromosome 22 that has been reported to be a specific abnormality in meningiomas. Publication Types: Case Reports PMID: 2804914 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 384: Lijec Vjesn. 1989 Dec;111(12):474-8. [Oncogenes in acute myeloid leukemia] [Article in Croatian] Aurer I, Labar B. The role of oncogenes in carcinogenesis is intensively studied. Certain oncogenes are often found in some kinds of tumors. In acute myeloid leukemia (AML), of all oncogenes presently known, only those belonging to the ras group are activated in a larger number of cases. In single cases myc, myb, sis, and ets oncogenes have been found. It is possible that a disorder in regulation of myc and myb protooncogenes exists in AML. Publication Types: Review PMID: 2699910 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 385: Oncogene. 1989 Dec;4(12):1425-32. Stage-specific transformation of murine B lineage cells by ras and myc. Overell RW, Weisser KE, Hess B, Namen AE, Grabstein KH. Department of Molecular Biology, Immunex Corporation, Seattle, Washington 98101. The retroviral vector delta RM coexpresses the v-Ha-ras and v-mycMC29 oncogenes, under the transcriptional control of the retroviral long terminal repeat and an internal SV40 promoter respectively. In this report, the transforming activity of the delta RM virus on murine pre-B cells has been compared and contrasted with its activity on mature splenic B cells. Infection of primary bone marrow cells, followed by growth in the Whitlock-Witte culture system, resulted in the rapid outgrowth of transformed pre-B cells. These cells grew to high saturation densities and could give rise to immortal, interleukin-7-independent progeny that were able to grow independently of stromal elements. In contrast, infection of mature B cells purified from murine spleen resulted in only a transient increase in proliferation, and no immortal B cell lines were obtained. This inability of delta RM to transform mature B lymphocytes was not due to a low infection frequency, since parallel experiments with ecotropic retroviruses conferring drug resistance showed that the mature B cells were readily infectable. Moreover, Northern analysis showed that the delta RM-infected mature B cells expressed ras and myc mRNAs to higher levels than the delta RM transformed pre-B cells. Thus, coexpression of ras and myc resulted in the transformation of primary pre-B cells but not of the mature B cells. The potential explanations for the stage-specific transforming activity of the delta RM retrovirus are discussed. PMID: 2687765 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 386: Br J Cancer. 1989 Dec;60(6):872-4. Restriction fragment length polymorphisms of L-myc and myb in human leukaemia and lymphoma in relation to age-selected controls. Chenevix-Trench G, Southall M, Kidson C. Queensland Institute of Medical Research, Brisbane, Australia. PMID: 2574989 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 387: Nippon Ketsueki Gakkai Zasshi. 1989 Nov;52(7):1137-46. [c-myc gene amplification and N-ras transforming gene in two cases of acute myelocytic leukemia with double minute chromosomes] [Article in Japanese] Tanaka K, Takechi M, Hong J, Shigeta C, Oguma N, Kamada N, Takimoto Y, Kuramoto A, Okita H. We report two leukemia patients with double minutes (DMs) chromosomes. Both patients were diagnosed as having acute myelocytic leukemia (AML) FAB M2. Cytogenetic analysis showed normal chromosome karyotype with 1-53 DMs chromosomes in the first patient, and complex chromosome aberrations including deletion of chromosome 8 at 8q24 region and 1-84 DMs chromosomes in the second patient who had a history of extensive radiotherapy for laryngeal cancer 8 years prior to the development of leukemia. Analysis of DNA from the two patients revealed that oncogene of c-myc was amplified about 5 to 10 folds in the leukemic cells. The other fourteen oncogene of c-myc was c-myb, c-abl and N-myc, showed no increases of gene content. Furthermore, a transforming gene, N-ras was detected in the first patient by in vivo selection assay method. This is the second report on AML patients with c-myc gene amplification and DMs chromosomes. Publication Types: Case Reports PMID: 2694722 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 388: Exp Cell Res. 1989 Nov;185(1):50-9. Distribution of c-myc, c-myb, and Ki-67 antigens in interphase and mitotic human cells evidenced by immunofluorescence staining technique. Bading H, Rauterberg EW, Moelling K. Max-Planck-Institut fur Molekulare Genetik, Abt. Schuster, Berlin 33, Federal Republic of Germany. Using specific antibodies and the immunofluorescence staining technique we found a similar subcellular distribution pattern of the cellular proto-oncogene proteins c-myc and c-myb in interphase and mitotic HL60 and Molt4 cells. Antibodies against c-myc as well as those against c-myb protein gave rise to a nuclear staining excluding the nucleoli. In mitotic cells both proteins are apparently not associated with the chromatin of the condensed chromosomes, but appear diffusely distributed throughout the cytoplasm. In contrast, immunostaining using the proliferation marker antibody Ki-67 yielded in both cell lines several prominent specks in the nucleus and a weak finely dispersed staining throughout the nucleoplasm. No fluorescence was detectable in the cytoplasm. In dividing cells Ki-67 immunofluorescence was found to be associated with the surface of the chromosomes. The functional significance of the different localizations of the proteins is discussed in light of what is currently known about nuclear antigens. PMID: 2680541 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 389: Cancer Res. 1989 Nov 1;49(21):5889-94. Gene activity during the early phase of androgen-stimulated rat prostate regrowth. Katz AE, Benson MC, Wise GJ, Olsson CA, Bandyk MG, Sawczuk IS, Tomashefsky P, Buttyan R. Department of Urology, Maimonides Medical Center, Brooklyn, New York 11219. Androgenic steroids regulate the proliferation rate of normal and malignant prostate cells. In order to investigate the molecular basis of this control, we utilized Northern and Western blot techniques to measure changes in the expression of individual genes during the early phase of prostate regrowth. Vestigial ventral prostate glands of 7-day castrated rats showed increased numbers of replicating cells within 12 h of continuous pharmacological testosterone replacement as demonstrated by flow cytometric procedures. The period prior to the onset of proliferative enhancement was accompanied by the sequential induction of a variety of transcripts encoding gene products often associated with cell growth. Within 1 h of treatment, mature mRNA transcripts for c-fos were induced 6-fold, returning to control levels by 2 h. Other genes showed transiently elevated transcript levels after 2 h (c-Ha-ras, c-Ki-ras) or after 8 h (c-myc,c-myb, beta-actin, and Mr 70,000 heat shock protein) of testosterone replacement. Expression of the polypeptide encoded by c-Ha-ras was coordinately enhanced (2-fold) during this period, but not to the levels of the transcript (20-fold induction). Transcripts encoding basic fibroblast growth factor were increased 16 h and later, subsequent to the earlier enhancement in the proliferation rate. By placing these genes in a defined temporal order with regard to their expression in response to testosterone, we have constructed a map of gene activity during early prostate regrowth. This map shows a number of genes, the products of which might participate in the mechanism by which androgens induce mitogenesis of prostate cells. PMID: 2571413 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 390: 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] --------------------------------------------------------------- 391: Kekkaku. 1989 Oct;64(10):657-67. [The characteristic changes of immune function with aging] [Article in Japanese] Negoro S, Hara H, Deguchi Y, Nishio S, Jia L, Wang J, Kishimoto S. It is well-known that the most prominent age-related immunological abnormalities were reduced immune response against foreign antigens and increased auto-antibody production against intrinsic antigens. To explain these immunological abnormalities, we examined the various functions of human lymphocytes from aged and young groups at cellular, molecular and genetic levels. The results indicate: The first, T cells from the aged showed significantly reduced proliferative response not only to specific antigen TAP but also to mitogen PHA or combined stimulation of PMA and ionomycin. The second, the number of IL-2 receptor, particularly high affinity ones, on aged T cells were significantly reduced in the aged after TAP and PHA stimulation. The third, the ability to express Tac (p55) and p70/75 of IL-2R and to internalize the rIL-2 bound to the receptor were reduced in aged T cells. The fourth, although the ability to proliferate in response to SAC stimulation was two folds less in the aged B cells than that in the young ones, the capacity to differentiate into IgG and IgA class ISC after the combined stimulation with SAC and partially purified BCDF were rather increased on the basis of the number of viable cells recovered. The fifth, the amount of IL-2 activity produced by aged T cells was ten fold less than that by young ones, but the amount of BCDF activity produced by aged T cells was three folds higher than that by young ones after PHA stimulation. An inverse correlation between IL-2 activity and BCDF activity was found when the both activities were determined in the same sample. The sixth, the combined stimulation with PMA and ionomycin could induce proliferative response to highly purified T cells, T cell subsets and B cells. The degree of age-related decline of the proliferative response of CD-8 positive T cells was most significant, that of CD-4 positive ones was next and that of B cells was least. The seventh, although the maximum of c-myc mRNA level was attained at 2 hr after the stimulation and similar amount between the both age groups, the amount of mRNA at 8 or 24 hr was rather higher in the aged T cells than in the young ones. The reduction of the degradation rate of c-myc mRNA seemed to be the cause. We found no difference of the maximum amount and kinetics of c-myb mRNA between both age groups in T cells.(ABSTRACT TRUNCATED AT 400 WORDS) PMID: 2811004 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 392: Br J Cancer. 1989 Oct;60(4):561-5. Structure and expression of nuclear oncogenes in multi-stage thyroid tumorigenesis. Wyllie FS, Lemoine NR, Williams ED, Wynford-Thomas D. CRC Thyroid Tumour Biology Research Group, Department of Pathology, University of Wales College of Medicine, Cardiff, UK. We have investigated the possibility that structural alterations of the 'nuclear' oncogene family (c-myc, N-myc, L-myc, fos, myb and p53) leading to aberrant expression might, as in several other tumour types, play a role in the multi-stage development of tumorigenesis in the human thyroid follicular cell. Direct analysis of expression by slot and Northern blot RNA hybridisation showed that normal thyroid expresses surprisingly high levels of fos, and to a lesser extent c-myc, c-myc expression was markedly increased in all tumours, both benign and malignant, but no increase was seen in any other nuclear oncogene. fos expression was reduced specifically in one type of malignant tumour-follicular carcinoma-in inverse correlation with differentiation. Southern blot analysis showed no evidence of rearrangement or amplification of c-myc, or of any other 'nuclear' oncogene in any thyroid tumour. We conclude that there is no evidence that a primary abnormality of these genes plays a role in thyroid follicular cell tumorigenesis and suggest that the observed changes in expression can be adequately explained as secondary consequences of the tumour phenotype. PMID: 2803926 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 393: Blood. 1989 Oct;74(5):1517-24. Nuclear oncoprotein expression as a function of lineage, differentiation stage, and proliferative status of normal human hematopoietic cells. Kastan MB, Stone KD, Civin CI. Johns Hopkins Oncology Center, Baltimore, MD. Relative levels of the nuclear oncoproteins c-myb, c-myc, and c-fos were determined in selected subpopulations of normal human bone marrow (BM) cells using a flow cytometric assay which simultaneously detects a cell-surface antigen (as a marker of lineage and stage of maturation) and levels of an intracellular protein. At least two monoclonal antibodies directed against each oncoprotein and specific peptide inhibition controls were used for these determinations. Hematopoietic progenitor cells (CD34+) express the highest levels of c-myb and c-myc, whereas c-fos levels in CD34+ progenitor cells are similar to c-fos levels in mature monocytes and granulocytes. Granulocytes are the only hematopoietic cells examined which do not express detectable levels of c-myb and c-myc. The levels of these oncoproteins in these normal, unstimulated BM cell populations were more closely linked to lineage and maturation stage than to the proliferative status of the given population, as determined by either DNA staining or expression of the cell-cycle specific nuclear protein, Ki67. This flow cytometric assay helps in interpreting the significance of oncoprotein levels in leukemia cells by allowing direct comparisons of a leukemia with the phenotypically similar "normal counterpart control" cell population in normal BM. PMID: 2506946 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 394: Development. 1989 Oct;107(2):265-74. Complementary patterns of expression of c-ets 1, c-myb and c-myc in the blood-forming system of the chick embryo. Vandenbunder B, Pardanaud L, Jaffredo T, Mirabel MA, Stehelin D. Institut National de la Sante et de la Recherche Medicale, Unite 186/Centre National de la Recherche Scientifique URA 1160, Institut Pasteur, Lille, France. We have used in situ hybridization to study the spatial and temporal distribution of the transcription of three cellular oncogenes encoding DNA-binding proteins, c-ets 1, c-myb and c-myc during the development of the chick embryo. c-ets 1 mRNA expression appears linked to the mesodermal lineage and is strongly expressed in early endothelia; it subsequently becomes restricted to small vessel endothelia. Hemopoietic cells in extraembryonic blood islands at E2 express c-ets 1, while intraembryonic hemopoietic cells in aortic clusters (E3) and paraaortic foci (E6) express c-myb. c-myc transcripts are detected in cells undergoing hemopoiesis in both these extraembryonic and intraembryonic sites. Outside the blood-forming system, c-myc is transcribed in a large variety of cells; c-ets 1 displays tissue-specific expression in groups of mesodermal cells engaged in morphogenetic processes and appears excluded from all epithelia; finally the expression of c-myb is the most tightly linked to hemopoietic cells. In any case, it is clear that these three oncogenes display complementary expression in endothelial and hemopoietic cells where their patterns are modulated in relationship to multiplication and differentiation. PMID: 2483681 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 395: J Neurosci Res. 1989 Sep;24(1):97-106. Patterns of proto-oncogene expression in human glioma cell lines. LaRocca RV, Rosenblum M, Westermark B, Israel MA. Medicine Branch, National Cancer Institute, Bethesda, MD 20892. Previously reported studies have suggested that variations in the pattern of proto-oncogene expression within a specific tumor type may denote an underlying difference in the biology and clinical behavior of those tumors. To more sensitively characterize malignant tumors of the central nervous system, we have used Northern blot hybridization analysis to determine the patterns of expression of seven proto-oncogenes in 20 cell lines established from biopsy specimens of patients with malignant glioma. The following proto-oncogenes are expressed at detectable levels in 30 micrograms of total RNA from most glioma cell lines examined: c-myc (20/20), c-mil/raf-1 (18/18), neu (19/20), c-erbB (19/20), and c-myb (17/20). In contrast, only half of the cell lines expressed detectable c-sis (10/20). In none of the cell lines tested was N-myc (0/20) mRNA detected. Morphologic analysis of these 20 cell lines revealed three different growth patterns: bipolar, epithelial, and pleomorphic-glial. Detectable levels of c-sis mRNA typically occurred with either an epithelial or pleomorphic-glial morphology. The pleomorphic-glial subgroup was also characterized by the expression of glial fibrillary acidic protein. PMID: 2810398 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 396: Cancer Res. 1989 Sep 1;49(17):4701-4. Altered expression of growth-regulated protooncogenes in human malignant plasma cells. Palumbo AP, Pileri A, Dianzani U, Massaia M, Boccadoro M, Calabretta B. Department of Medicine and Experimental Oncology, School of Medicine, University of Torino, Italy. The expression of three growth-regulated protooncogenes, c-myc, c-myb, and p53, and the S-phase-specific histone H3 gene, was compared in bone marrow cells from multiple myeloma patients and normal controls by measuring the amount of specific RNA by Northern blot analysis. Four samples contained at least 72% of myeloma cells, one sample 43%, and one 11%. Expression of the protooncogenes was similar in normal and myeloma bone marrow cells, whereas that of histone H3 gene was significantly reduced (between 10 and 15 times) in samples containing at least 43% of malignant plasma cells and not detectable in those containing more than 72% of neoplastic cells. Protooncogene levels of expression were compared to those of the H3 gene to distinguish the increased expression of a growth-regulated gene due to a true deregulation from overexpression reflecting solely an increase in the fraction of cycling cells. The ratios of expression of protooncogenes to histone H3 were markedly increased in multiple myeloma cells; the highest ratios were found in the patients with the highest number of malignant plasma cells. These results suggest that the expression of three growth-regulated oncogenes (c-myc, c-myb, p53) is altered in myelomatous plasma cells. PMID: 2667753 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 397: J Virol. 1989 Aug;63(8):3382-8. Two nuclear oncogenic proteins, P135gag-myb-ets and p61/63myc, cooperate to induce transformation of chicken neuroretina cells. Amouyel P, Laudet V, Martin P, Li RP, Quatannens B, Stehelin D, Saule S. Institut National de la Sante et de la Recherche Medicale, U 186, Centre National de la Recherche Scientifique, URA 0156, Institut Pasteur de Lille, France. Several studies have shown that full transformation of primary rodent fibroblasts can be achieved in vitro through the cooperation of two oncogenes (usually one nuclear and one cytoplasmic) classified on the basis of different complementation groups. We have shown previously that cooperation between v-mil (cytoplasmic, serine-threonine kinase product), and v-myc (nuclear, DNA-binding product) is required to transform 7-day-old chicken neuroretina cells, which in usual culture medium do not rapidly proliferate. v-mil induces sustained growth of chicken neuroretina cells without transformation; v-myc fails to stimulate the proliferation of chicken neuroretina cells but is required to achieve transformation of the proliferating cells. Here, we present results indicating that the P135gag-myb-ets nuclear protein of avian erythroblastosis virus E26 is able to induce proliferation but not transformation of chicken neuroretina cells. v-myc is required in addition to P135gag-myb-ets to achieve chicken neuroretina cell transformation. In contrast, we found that the P135gag-myb-ets and P100gag-mil proteins are not able to cooperate in this system. PMID: 2664218 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 398: J Virol. 1989 Aug;63(8):3220-6. Activation of endogenous c-fos proto-oncogene expression by human T-cell leukemia virus type I-encoded p40tax protein in the human T-cell line, Jurkat. Nagata K, Ohtani K, Nakamura M, Sugamura K. Department of Microbiology, Tohoku University School of Medicine, Sendai, Japan. We examined the ability of the trans-acting factor p40tax of human T-cell leukemia virus type I (HTLV-I), which is thought to be a crucial molecule in T-cell transformation by HTLV-I, to activate expression of a set of endogenous cellular genes related to T-cell proliferation. For this purpose we established a subclone (JPX-9) of Jurkat cells that was stably transfected with an expression plasmid containing the p40tax gene, whose expression is definitely dependent on heavy-metal ions. Expression of the interleukin-2 receptor alpha chain in JPX-9 cells was induced in response to the induction of p40tax expression, as has been demonstrated by others in transient transfection experiments with Jurkat cells. In addition, we found that significant enhancement of expression of the nuclear proto-oncogene c-fos was closely associated with expression of p40tax. Continous enhancement in the level of c-fos mRNA was observed in the presence of p40tax. In contrast, mRNA levels of other nuclear proto-oncogenes (c-myc, c-myb, and c-jun) were not appreciably effected by the expression of p40tax. These results suggest that (i) in addition to the interleukin-2-interleukin-2 receptor system, cellular genes such as c-fos, which regulate normal T-cell growth, are also activated directly or indirectly by p40tax and (ii) p40tax-induced modulation of gene expression plays a crucial role in T-cell transformation by HTLV-I. PMID: 2501514 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 399: Science. 1989 Jul 14;245(4914):180-3. G1/S transition in normal human T-lymphocytes requires the nuclear protein encoded by c-myb. Gewirtz AM, Anfossi G, Venturelli D, Valpreda S, Sims R, Calabretta B. Department of Medicine, Temple University School of Medicine, Philadelphia, PA 19140. Exposure of peripheral blood mononuclear cells (PBMC) to an 18-base c-myb antisense oligomer before mitogen or antigen stimulation resulted in almost complete inhibition of c-myb messenger RNA and protein synthesis and blockade of T lymphocyte proliferation. Expression of early and late activation markers, interleukin-2 receptor and transferrin receptor, respectively, by PBMC was unaffected by antisense oligomer exposure as was the expression of c-myc messenger RNA. In contrast, histone H3 messenger RNA levels and DNA content were selectively decreased. These results suggest that c-myb protein deprivation does not perturb T lymphocyte activation or early molecular events that may prepare the cell for subsequent proliferation. Rather, it appears to specifically block cells in late G1 or early S phase of the cell cycle. PMID: 2665077 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 400: J Exp Med. 1989 Jul 1;170(1):105-21. Regulation of T lymphocyte proliferation. Interleukin 2-mediated induction of c-myb gene expression is dependent on T lymphocyte activation state. Churilla AM, Braciale TJ, Braciale VL. Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110. We previously reported that with time, after antigenic stimulation of antigen-regulated murine T lymphocyte clones, total IL-2-R expression decayed 10-50-fold, commensurate with a decline in the ability of the cells to proliferate to IL-2. However, late after antigenic stimulation, when the cells were refractory to the IL-2-proliferative stimulus, high levels of high affinity IL-2-R remained. In this report we further explore the basis of unresponsiveness to IL-2 in the quiescent clones. We show that the proto-oncogene c-myc is induced in the late cell population by IL-2 to comparable levels observed early after antigen stimulation. IL-2-dependent c-myb induction, however, is seen only early after activation but not in the late-activated population. Analysis of the IL-2-dependent expression of c-myb mRNA with time after antigenic stimulation showed that steadystate c-myb expression declines dramatically with kinetics closely paralleling a decay in IL-2-dependent proliferative ability. In contrast, steadystate c-myc expression remains high throughout this period. Expression of c-myb is critical for proliferation of these cells since antisense oligodeoxy-nucleotide to c-myb can inhibit their IL-2-dependent proliferation. We present evidence for a pathway of c-myb induction via the TCR that is independent of the IL-2/IL-2-R interaction. In addition, the inhibition of IL-2-R-induced c-myb expression by 2-aminopurine and enhanced induction of c-myb via the TCR demonstrate that TCR activation and IL-2-R activation lead to induction of c-myb by different mechanisms. PMID: 2664066 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 401: Blood. 1989 Jul;74(1):423-9. Histologic typing of non-Hodgkin's lymphomas by in situ hybridization with DNA probes of oncogenes. Hamatani K, Yoshida K, Kondo H, Toki H, Okabe K, Motoi M, Ikeda S, Mori S, Shimaoka K, Akiyama M, et al. Department of Pathology, Nagasaki University School of Medicine, Japan. Expression of six proto-oncogenes (fos, myc, myb, Ki-ras, Ha-ras, and N-ras) in 43 cases of non-Hodgkin's lymphoma was analyzed by means of in situ hybridization. Biotinylated DNA probes of the six oncogenes and those of immunoglobulin H (IgH) gene and T-cell receptor beta (TCR beta) chain gene were used. The results of in situ hybridization performed under blind conditions by IgH gene and TCR beta chain gene probes were compatible with those of typing by cell surface markers. The nuclear protein-related proto-oncogenes, fos, myc, and myb, were expressed in about 70% to 80% of all cases regardless of phenotype, histology, or histologic grade. On the contrary, genes of ras family were expressed in more limited numbers of cases except for the Ki-ras gene, which was more frequently expressed by cases of the T-cell immunophenotype with a high malignancy grade. The results of dot hybridization with RNA extracted from some cases were compatible with those of in situ hybridization, further demonstrating the specificity of in situ hybridization. PMID: 2526666 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 402: Int J Cancer. 1989 Jun 15;43(6):1120-5. Retrovirally induced murine B-cell tumors rarely show proviral integration in sites common in T-cell tumors. Matthews EA, Vasmel WL, Schoenmakers HJ, Melief CJ. Division of Immunology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Huis, Amsterdam. The molecular etiology of retrovirally induced T-cell tumors has been shown in many cases to involve proviral integration near a cellular oncogene, c-myc, N-myc, Pim-1 and pvt-1 being frequent targets for insertional activation. Murine B-cell tumors induced by infection with murine leukemia virus have been studied for rearrangements in these and other loci. In contrast to the T-cell lymphomas, tumors of the B-cell lineage, either early B-cell tumors induced in nude mice or late B-cell tumors in immunocompetent mice, did not show disruption of N-myc or Pim-1 in any of the tumors studied, although those lymphomas had acquired many new proviruses. The loci c-abl, bcl-2, fis-1, c-erbB, c-myb, and neu were likewise not involved. Rearrangement of c-myc was seen in 1 out of 71 and rearrangement of the pvt-1 locus in 4 out of 73 (5%) of the B-cell tumors. Thus it appears that mechanistic differences exist in the development of T-cell tumors and B-cell tumors caused by the same etiological agent. PMID: 2543645 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 403: Mol Cell Biol. 1989 Jun;9(6):2332-40. Rapid induction of polyadenylated H1 histone mRNAs in mouse erythroleukemia cells is regulated by c-myc. Cheng GH, Skoultchi AI. Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461. Chemically induced differentiation of murine erythroleukemia cells is a multistep process involving a precommitment period in which exposure to inducer leads to cells that are irreversibly committed to terminal differentiation. Certain changes in the expression of cellular proto-oncogenes are an important feature of the precommitment phase. We have identified two H1 histone genes that are rapidly induced during this period. Unlike most histone genes, these two H1 genes encode polyadenylated mRNAs with long 3' untranslated regions. To investigate the relationship between induction of the H1 mRNAs and changes in proto-oncogene expression, we studied two independent series of mouse erythroleukemia cell lines that are inhibited from differentiating because of deregulated expression of transfected copies of c-myc or c-myb. The results showed that induction of the H1 mRNAs was negatively regulated by c-myc. The two H1 histone genes are among the first examples of specific cellular genes that are regulated by c-myc. The timing of their induction suggests that they may play an important role in achieving commitment to terminal differentiation. PMID: 2668731 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 404: Am J Vet Res. 1989 Jun;50(6):978-83. Comment in: Am J Vet Res. 1989 Nov;50(11):1990-1. DNA polymorphism analysis of hereditary multiple exostoses in horses. Li JK, Moloney BK, Shupe JL, Gardner EJ, Leone NC, Elsner Y. Molecular Biology/Biochemistry Program, Utah State University, Logan 84322-5500. Genomic DNA polymorphisms obtained by restriction fragment-length polymorphism from healthy horses and horses with hereditary multiple exostoses were analyzed. These DNA were digested by 12 restriction enzymes and were hybridized against 6 isotopically labeled oncogene probes. Hybridization was not detected with the viral oncogene, v-ras, which indicated this oncogene was absent in the equine genome. Oncogenes (c-raf-1, c-fes, c-myb, c-myc, and c-sis) were present and had similar hybridization patterns and signal intensities in DNA from healthy horses and horses with hereditary multiple exostoses. Unique and distinct restriction fragment-length polymorphisms were detected with the c-raf-1 probe only in BamHI- and PstI-digested equine DNA. PMID: 2569854 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 405: Mol Cell Biol. 1989 Jun;9(6):2657-64. Multiple proto-oncogene activations in avian leukosis virus-induced lymphomas: evidence for stage-specific events. Clurman BE, Hayward WS. Sloan-Kettering Institute for Cancer Research, New York, New York 10021. We have examined avian leukosis virus-induced B-cell lymphomas for multiple, stage-specific oncogene activations. Three targets for viral integration were identified: c-myb, c-myc, and a newly identified locus termed c-bic. The c-myb and c-myc genes were associated with different lymphoma phenotypes. The c-bic locus was a target for integration in one class of lymphomas, usually in conjunction with c-myc activation. The data indicate that c-myc and c-bic may act synergistically during lymphomagenesis and that c-bic is involved in late stages of tumor progression. PMID: 2548084 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 406: J Biol Chem. 1989 May 25;264(15):8922-7. Polyamines differentially modulate the transcription of growth-associated genes in human colon carcinoma cells. Celano P, Baylin SB, Casero RA Jr. Johns Hopkins Oncology Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231. Increases in the transcription of genes important to cell growth frequently occur in concert with increases in intracellular polyamines after a mitogenic stimulus. Previously, we have shown that depletion of intracellular polyamines by 2-difluoromethylornithine in COLO 320 cells resulted in a significant decrease in c-myc mRNA steady state levels. We demonstrate here that polyamines have a predominant role in the regulation of transcription of c-myc, c-fos, and histone 2A, while they appear to have both a transcriptional and post-transcriptional role in expression of c-myb, ornithine decarboxylase, and beta-actin mRNA levels. We further analyzed the effect of spermidine in overall and specific RNA transcription in isolated nuclei from COLO 320 cells. In nuclei from control cells, the addition of spermidine resulted in a 3-4 increase in overall [alpha-32P]UTP incorporation and a 4-8-fold increase in c-myc, c-fos, and histone 2A transcription. In contrast, ornithine decarboxylase and c-myb gene transcription were unaffected. Furthermore, in nuclei from 2-difluoromethylornithine-treated COLO 320 cells, spermidine addition resulted in less than a 2-fold increase in RNA transcription and had no effect on any specific gene analyzed. These results indicate that polyamines may have an important role in the transcription of specific growth related genes, especially c-myc and c-fos, and this role may be one mechanism by which polyamines modulate cell growth. PMID: 2498320 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 407: Mol Cell Biol. 1989 May;9(5):1996-2006. Regulation of c-myc mRNA stability in vitro by a labile destabilizer with an essential nucleic acid component. Brewer G, Ross J. McArdle Laboratory for Cancer Research, University of Wisconsin, Madison 53706. The turnover rates of some mRNAs vary by an order of magnitude or more when cells change their growth pattern or differentiate. To identify regulatory factors that might be responsible for this variability, we investigated how cytosolic fractions affect mRNA decay in an in vitro system. A 130,000 X g supernatant (S130) from the cytosol of exponentially growing erythroleukemia cells contains a destabilizer that accelerates the decay of polysome-bound c-myc mRNA by eightfold or more compared with reactions lacking S130. The destabilizer is deficient in or absent from the S130 of cycloheximide-treated cells, indicating that it is labile or is repressed when translation is blocked. It is not a generic RNase, because it does not affect the turnover of delta-globin, gamma-globin, or histone mRNA and does not destabilize a major portion of polysomal polyadenylated mRNA. The destabilizer accelerates the turnover of the c-myc mRNA 3' region, as well as subsequent 3'-to-5' degradation of the mRNA body. It is inactivated in vitro by mild heating and by micrococcal nuclease, suggesting that it contains a nucleic acid component. c-myb mRNA is also destabilized in S130-supplemented in vitro reactions. These results imply that the stability of some mRNAs is regulated by cytosolic factors that are not associated with polysomes. PMID: 2747642 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 408: Eur Respir J. 1989 May;2(5):461-9. Comment in: Eur Respir J. 1989 Nov;2(10):1022. The molecular genetics of human lung cancer. Slebos RJ, Rodenhuis S. Division of Experimental Therapy, The Netherlands Cancer Institute, Amsterdam. With the development of molecular biological techniques the search for genetic alterations in cancer cells has resulted in the beginning of a molecular description of cellular transformation. Most of these genetic changes occur in genes which have a role in the control of cellular growth and development, the proto oncogenes. In the last decade, it has become clear that the myc and ras oncogene families are important in the carcinogenesis of human lung cancers. The myc oncogenes are usually found to be altered in small cell lung cancer (SCLC), and these alterations appear to correlate with rapid growth and progression. Mutations in the Kras gene are specific for adenocarcinoma, a subclass of non small cell lung cancer (NSCLC). Kras gene mutations are closely associated with tobacco smoking, since all were found in adenocarcinomas from patients with a history of smoking. The erbB oncogene, which encodes the epidermal growth factor receptor, is often highly expressed in epidermoid carcinomas. The roles for other oncogenes, such as raf or myb, as well as those of "suppressor" genes remain to be investigated, but may be of paramount importance. The study of alterations in proto oncogenes may aid in the (sub)classification and diagnosis of lung cancer, and may yield useful prognostic information in the near future. Publication Types: Review Review, Tutorial PMID: 2547647 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 409: Proc Natl Acad Sci U S A. 1989 May;86(9):3379-83. An oligomer complementary to c-myb-encoded mRNA inhibits proliferation of human myeloid leukemia cell lines. Anfossi G, Gewirtz AM, Calabretta B. Department of Pathology, Temple University School of Medicine, Philadelphia, PA 19140. To study the role of the protooncogene c-myb in regulating myeloid leukemia cell proliferation and differentiation, we exposed cells of the human leukemia lines HL-60, ML-3, KG-1, and KG-1a to an oligodeoxynucleotide complementary to an 18-base-pair (bp) sequence of c-myb-encoded mRNA. This treatment resulted in a significant decrease in cell proliferation in all of the lines, which was most marked in HL-60 cells. After 5 days in culture, in several separate experiments with different oligomer preparations, 75% growth inhibition was observed in c-myb antisense treated cells in comparison to untreated HL-60 cells. Two c-myb antisense oligomers of identical length with either 2- or 4-bp mismatches had no effect on cell growth nor did an 18-bp c-myb sense or myeloperoxidase antisense oligomer. The effect of a c-myc antisense oligomer (18 bp) on the growth of HL-60, KG-1, and KG-1a cells was also studied. This oligomer had much less inhibitory effect on cell proliferation than did the c-myb antisense sequence. Interestingly, although c-myc antisense treatment induced maturation of HL-60 cells while it inhibited cell proliferation, such an effect was not noted in c-myb antisense treated cells. These studies indicate that the nuclear protein encoded by the c-myb protooncogene is required for maintenance of proliferation in certain leukemia cell lines. In compared to c-myc protein suggest that, at least in HL-60 cells, c-myc amplification or N-ras activation may not be sufficient to maintain the leukemic growth in the absence of c-myb protein. These findings support the hypothesis that development and maintenance of a malignant phenotype requires a multiplicity of interrelated genetic events. PMID: 2541445 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 410: J Clin Invest. 1989 May;83(5):1477-86. Inhibition of human megakaryocytopoiesis in vitro by platelet factor 4 (PF4) and a synthetic COOH-terminal PF4 peptide. Gewirtz AM, Calabretta B, Rucinski B, Niewiarowski S, Xu WY. Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140. We report that highly purified human platelet factor 4 (PF4) inhibits human megakaryocytopoiesis in vitro. At greater than or equal to 25 micrograms/ml, PF4 inhibited megakaryocyte colony formation approximately 80% in unstimulated cultures, and approximately 58% in cultures containing recombinant human IL 3 and granulocyte-macrophage colony-stimulating factor. Because PF4 (25 micrograms/ml) had no effect on either myeloid or erythroid colony formation lineage specificity of this effect was suggested. A synthetic COOH-terminal PF4 peptide of 24, but not 13 residues, also inhibited megakaryocyte colony formation, whereas a synthetic 18-residue beta-thromboglobulin (beta-TG) peptide and native beta-TG had no such effect when assayed at similar concentrations. The mechanism of PF4-mediated inhibition was investigated. First, we enumerated total cell number, and examined cell maturation in control colonies (n = 200) and colonies (n = 100) that arose in PF4-containing cultures. Total cells per colony did not differ dramatically in the two groups (6.1 +/- 3.0 vs. 4.2 +/- 1.6, respectively), but the numbers of mature large cells per colony was significantly decreased in the presence of PF4 when compared with controls (1.6 +/- 1.5 vs. 3.9 +/- 2.3; P less than 0.001). Second, by using the human leukemia cell line HEL as a model for primitive megakaryocytic cells, we studied the effect of PF4 on cell doubling time, on the expression of both growth-regulated (H3, p53, c-myc,and c-myb), and non-growth-regulated (beta 2-microglobulin) genes. At high concentrations of native PF4 (50 micrograms/ml), no effect on cell doubling time, or H3 or p53 expression was discerned. In contrast, c-myc and c-myb were both upregulated. These results suggested the PF4 inhibited colony formation by impeding cell maturation, as opposed to cell proliferation, perhaps by inducing expression of c-myc and c-myb. The ability of PF4 to inhibit a normal cell maturation function was then tested. Megakaryocytes were incubated in synthetic PF4, or beta-TG peptides for 18 h and effect on Factor V steady-state mRNA levels was determined in 600 individual cells by in situ hybridization. beta-TG peptide had no effect on FV mRNA levels, whereas a approximately 60% decrease in expression of Factor V mRNA was found in megakaryocytes exposed to greater than or equal 100 ng/ml synthetic COOH-terminal PF4 peptide. Accordingly, PF4 modulates megakaryocyte maturation in vitro, and may function as a negative autocrine regulator of human megakaryocytopoiesis. PMID: 2523411 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 411: Oncogene. 1989 May;4(5):583-92. Proto-oncogene expression and dissection of the myeloid growth to differentiation developmental cascade. Liebermann DA, Hoffman-Liebermann B. Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104. Physiological inducers of myeloid cell growth and differentiation were used to simultaneously analyze the expression of the proto-oncogenes c-myc, c-myb, c-fos, c-fes and c-fms during normal myelopoiesis, where growth is coupled to differentiation, as compared with that in leukemia, where growth has been uncoupled from differentiation as well as upon suppression of the leukemic phenotype via induction of differentiation and growth arrest. Proto-oncogene expression was also used as a tool to dissect the growth to differentiation developmental cascade. Myeloid cell growth was correlated with high c-myc and c-myb RNA levels, decreasing to undetectable levels in terminally differentiated cells. No c-myc RNA was detected in normal myeloid progenitors induced for differentiation without growth, using media conditioned by mouse granulocytes (GCM), indicating that c-myc may play either no role or an inhibitory one in differentiation. RNA levels of the proto-oncogenes c-fos, c-fes and c-fms were undetectable in normal or M1 differentiation inducible (D+) leukemic myeloblasts, and were stably induced upon stimulation of the normal precursors for growth and differentiation, with highest levels at the time when most of the cells had undergone terminal differentiation. Only c-fes RNA was induced upon M1D+ differentiation. It was also shown to be induced upon induction of differentiation without growth in normal myeloid precursors. Using c-myc and c-myb RNA suppression as molecular markers for induction of M1D+ differentiation, the existence of myeloid differentiation factor(s), distinct from myeloid growth factors, has been demonstrated. Such differentiation inducing activity was found in media conditioned by mouse lungs or granulocytes, and was induced in normal myeloid precursors by the myelopoietic growth factors IL3, GM-CSF, G-CSF, and M-CSF. Taken together, the results of this study enhance and add to previous work to better correlate the expression of the proto-oncogenes myc, myb, fes, fos and fms with several parameters of normal and abnormal myeloid cell growth and differentiation. The results indicate that the normal myeloid growth to differentiation developmental cascade entails a mechanism whereby myeloid growth factors induce myeloid differentiation factors, subsequently suppressing c-myc and c-myb RNA expression, leading to the induction of differentiation and growth arrest, including early accumulation of c-fes RNA followed by accumulation of c-fos and c-fms RNAs. It was also indicated that this cascade is impaired in leukemia. PMID: 2471131 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 412: J Biol Chem. 1989 Apr 25;264(12):6990-5. Heparin prevents vascular smooth muscle cell progression through the G1 phase of the cell cycle. Reilly CF, Kindy MS, Brown KE, Rosenberg RD, Sonenshein GE. Department of Biology, Massachusetts Institute of Technology, Cambridge 02139. To gain insight into the mechanism of the antiproliferative effects of heparin on vascular smooth muscle cells (SMC), the influence of this glycosaminoglycan on cell cycle progression and the expression of the c-fos, c-myc, and c-myb proto-oncogenes and two other growth-regulated genes was examined. SMC, synchronized by a serum-deprivation protocol, enter S phase 12-16 h after serum stimulation. Pretreatment with heparin for 48 h blocked the induction of histone H3 RNA, an S phase-expressed product, and prevented cell replication. Thus, heparin prevents entry of cells into S phase. Conversely, heparin had essentially no effect on changes in expression of the c-fos and c-myc proto-oncogenes during the G0 to G1 transition. Normal increases in c-fos and c-myc RNA were observed 30 min and 2 h following serum addition, respectively. However, the increase in expression of the mRNA of the c-myb proto-oncogene and the mitochondrial ATP/ADP carrier protein, 2F1, which begins to occur 8 h following serum addition to SMC, was completely inhibited by heparin. Two-dimensional polyacrylamide gel electrophoresis of the products of a rabbit reticulocyte cell-free translation of RNA isolated at various times confirmed this temporal assessment of the effects of heparin. These results suggest that heparin does not inhibit cell proliferation by blocking the G0 to G1 transition. Rather, heparin may affect a critical event in the mid-G1 phase of the cell cycle which is necessary for subsequent DNA synthesis. PMID: 2651437 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 413: Biochem Biophys Res Commun. 1989 Apr 14;160(1):181-8. Mechanism of T cell proliferation in vivo: analysis of IL-2 receptor expression and activation of c-myc and c-myb oncogenes during lymphatic regeneration. Sihvola M, Sistonen L, Alitalo K, Hurme M. Department of Bacteriology, University of Helsinki, Finland. The mechanism of T cell proliferation was studied using in vivo lymphatic regeneration as the model. Lymphatic regeneration was induced by injecting a sublethal dose (300 mg/kg) of cyclophosphamide (Cy) into mice. Majority of the regenerating splenic T cells were found to be in the cell cycle, nearly 30% being found in S/G2+M phases resembling the ratio obtained for mitogen activated T cells in vitro. Expression of interleukin-2 receptor (IL-2R) was defined by the monoclonal anti-IL-2R antibody, AMT-13. Only 1-3% of regenerating T cells were IL-2R positive (while about 30% of the in vitro activated T cells were IL-2R positive). Accordingly, these cells did not respond to IL-2 in vitro. However, when the freshly isolated regenerating T cells were cultured in the presence of Con A or PMA + ionophore A 23187, IL-2R was readily induced. The regenerating T cells were further analyzed for the expression of the cellular oncogenes c-myc and c-myb. These cells expressed about three times more c-myb mRNA than Con A-stimulated T cells and the levels were comparable to those seen in thymocytes. By contrast, the amount of c-myc mRNA was similar in the regenerating T cells and in Con A-activated T cells, but weak or barely detectable in splenocytes and thymocytes. Taken together, our results imply that the vigorous T cell proliferation during cyclophosphamide-induced lymphatic regeneration is independent of the IL-2/IL-2R hormone system, like T-cell precursor proliferation in the thymus, and is characterized by both high c-myb expression typical for thymocytes and high c-myc expression typical for in vitro proliferation-activated T cells. PMID: 2496686 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 414: Arthritis Rheum. 1989 Apr;32(4):430-6. Increased proto-oncogene expression in peripheral blood T lymphocytes from patients with systemic sclerosis. Kahan A, Gerfaux J, Kahan A, Joret AM, Menkes CJ, Amor B. INSERM U-283, Hopital Cochin, Paris, France. The expression of c-myc, c-myb, and c-ras proto-oncogenes, determined using RNA hybridization techniques (slot-blot), was significantly increased in peripheral blood T lymphocytes, but not in B cells, from 17 patients with systemic sclerosis with diffuse scleroderma, compared with the expression in normal control subjects. The magnitude of expression of c-myc and c-myb tended to be higher in patients with early, active disease. These results demonstrate an in vivo activation of T cells from systemic sclerosis patients, which may play an important role in the pathogenesis of the disease. PMID: 2784967 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 415: EMBO J. 1989 Apr;8(4):1111-9. Myc oncoproteins are phosphorylated by casein kinase II. Luscher B, Kuenzel EA, Krebs EG, Eisenman RN. Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98104. Casein kinase II (CK-II) is a ubiquitous protein kinase, localized to both nucleus and cytoplasm, with strong specificity for serine residues positioned within clusters of acidic amino acids. We have found that a number of nuclear oncoproteins share a CK-II phosphorylation sequence motif, including Myc, Myb, Fos, E1a and SV40 T antigen. In this paper we show that cellular myc-encoded proteins, derived from avian and human cells, can serve as substrates for phosphorylation by purified CK-II in vitro and that this phosphorylation is reversible. One- and two-dimensional mapping experiments demonstrate that the major phosphopeptides from in vivo phosphorylated Myc correspond to the phosphopeptides produced from Myc phosphorylated in vitro by CK-II. In addition, synthetic peptides with sequences corresponding to putative CK-II phosphorylation sites in Myc are subject to multiple, highly efficient phosphorylations by CK-II, and can act as competitive inhibitors of CK-II phosphorylation of Myc in vitro. We have used such peptides to map the phosphorylated regions in Myc and have located major CK-II phosphorylations within the central highly acidic domain and within a region proximal to the C terminus. Our results, along with previous studies on myc deletion mutants, show that Myc is phosphorylated by CK-II, or a kinase with similar specificity, in regions of functional importance. Since CK-II can be rapidly activated after mitogen treatment we postulate that CK-II mediated phosphorylation of Myc plays a role in signal transduction to the nucleus. PMID: 2663470 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 416: Mol Cell Biol. 1989 Apr;9(4):1714-20. Continued withdrawal from the cell cycle and regulation of cellular genes in mouse erythroleukemia cells blocked in differentiation by the c-myc oncogene. Coppola JA, Parker JM, Schuler GD, Cole MD. Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544. Constitutive expression of the c-myc oncogene blocks dimethyl sulfoxide (DMSO)-induced differentiation of mouse erythroleukemia (MEL) cells. During the first 12 h of treatment with DMSO, MEL cells undergo a temporary decrease in the level of c-myc mRNA, followed by a temporary withdrawal from the cell cycle. We found the same shutoff of DNA synthesis during the first 12 to 30 h after DMSO induction in normal MEL cells (which differentiate) and in c-myc-transfected MEL cells (which do not differentiate). We also examined whether deregulated c-myc expression grossly interfered with the regulation of gene expression during MEL cell differentiation. We used run-on transcription assays to monitor the rate of transcription of four oncogenes (c-myc, c-myb, c-fos, and c-K-ras); all except c-K-ras showed a rapid but temporary decrease in transcription after induction in both c-myc-transfected and control cells. Finally, we found the same regulation of cytoplasmic mRNA expression in both types of cells for four oncogenes and three housekeeping genes associated with growth. We conclude that in the MEL cell system, the effects of deregulated c-myc expression do not occur through a disruption of cell cycle control early in induction, nor do they occur through gross deregulation of gene expression. PMID: 2657403 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 417: Am J Hum Genet. 1989 Apr;44(4):577-84. Oncogenes and human breast cancer. Hall JM, Zuppan PJ, Anderson LA, Huey B, Carter C, King MC. School of Public Health, University of California, Berkeley 94720. The role of oncogenes in breast tumorigenesis is unclear. Alterations and/or amplification of several oncogene sequences have been observed in primary human breast tumors, in breast tumor cell lines, and in mammary tumors in model systems. In principle, such alterations could be sites of primary lesions for human breast cancer, causes of tumor progression or metastasis, or simply secondary lesions of highly aberrant tumor genomes. The present study tested genetic linkage of breast cancer susceptibility to nine oncogenes in 12 extended families including 87 affected individuals. Lod scores for close linkage of each candidate sequence to breast cancer were -19.6 for HRAS, -12.3 for KRAS2, -1.0 for NRAS, -6.0 for MYC, -6.1 for MYB, -8.2 for ERBA2, -7.9 for INT2, and -5.1 for RAF1. Regions of chromosome 11p associated with tumor homozygosity and the region of 3p carrying the gene for Von Hippel-Lindau disease could also be excluded from linkage to human breast cancer. The 5-kb allele of the MOS oncogene, previously proposed to be associated with breast cancer, was absent in these families, suggesting that polymorphism at this locus is not associated with inherited susceptibility. These results strongly suggest that oncogenes are not the sites of primary alterations leading to breast cancer. On the other hand, alterations in one or more of these sequences may be associated with tumor progression. PMID: 2564734 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 418: J Virol. 1989 Apr;63(4):1630-40. RAV-1 insertional mutagenesis: disruption of the c-myb locus and development of avian B-cell lymphomas. Pizer E, Humphries EH. Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235-9048. Infection of young chickens with RAV-1, a subgroup A isolate of avian leukosis virus, results in the development of lymphoid leukosis, a B-cell lymphoma characterized by provirus insertion into the c-myc locus. We report here that when 12- to 13-day-old embryos rather than 1-day-old chickens were infected with RAV-1, a novel B-cell lymphoma developed in which proviral insertions had activated expression of the c-myb gene. These tumors expressed elevated levels of a 4.5-kilobase myb-containing mRNA transcript that contained c-myb sequences not found in v-myb. The c-myc locus in these tumors appeared normal. The biological properties of the activated myb lymphoma were distinct from those of lymphoid leukosis. Metastatic disease developed within 7 weeks of infection. Distinct intermediate pathogenic stages with preneoplastic and primary neoplastic lesions were not detected. Although bursal tissues appeared to be nonmalignant on gross examination, Southern analyses of bursal DNA revealed the presence of tumor with the same clonal origin as abdominal lymphoma masses. The dependence on embryonic infection for development of activated myb lymphoma suggests that the target cells in which c-myb is activated are found only in embryos and are distinct from those cells that give rise to lymphoid leukosis. PMID: 2538646 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 419: Int J Cell Cloning. 1989 Mar;7(2):68-91. Origins and properties of hematopoietic growth factor-dependent cell lines. Ihle JN, Askew D. Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38101. Studies of the growth regulation, differentiation and transformation of myeloid cells have been greatly facilitated by the availability of a variety of hematopoietic growth factor-dependent cell lines. These cell lines have been isolated from long-term bone marrow cultures and myeloid tumors using interleukin 3 (IL-3) as a growth factor. Using growth factor-dependent cells, it has been shown that growth regulation by IL-3 involves binding to a high-affinity receptor of 140 Kd and activation of tyrosine phosphorylation. IL-3 binding is associated with a number of cellular responses which are required for maintenance of viability, including induction of transcription of the c-myc and ornithine decarboxylase (ODC) genes. In addition, IL-3 regulates the expression of transcription of the gamma T cell receptor locus. The properties of the IL-3-dependent lines are consistent with the hypothesis that they are transformed in their ability to terminally differentiate. In some of the cell lines, this transformation may terminally differentiate. In other of the cell lines, this transformation may be due to the altered expression of the c-myb gene. In other cell lines, transformation is associated with the activation of the expression of a novel gene, termed Evi-1, of the zinc finger family of transcriptional factors. Comparable transformation of erythroid lineage cells is speculated to be due to the activation of the expression of another novel gene termed spi-1. These studies have emphasized the value of well-characterized hematopoietic growth factor-dependent cell lines in advancing our understanding in the basic biology of myeloid cells. Publication Types: Review Review, Tutorial PMID: 2656885 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 420: Dev Biol. 1989 Mar;132(1):69-72. Nuclear run-on transcription from primary embryonic lens tissue. Zelenka PS, Pallansch LA, Vatal M. Laboratory of Molecular and Developmental Biology, National Eye Institute, Bethesda, Maryland 20892. We have devised an in vitro RNA elongation assay (nuclear "run-on" transcription) that is suitable for use with small amounts of primary embryonic tissue. The assay is sensitive enough to detect transcription of single-copy genes in 8 X 10(5) nuclei isolated from embryonic chicken lens epithelia, and gives no detectable hybridization to unrelated DNAs, such as phi X or pBR322. We have used this assay to examine transcription of delta-crystallin and six proto-oncogenes in lens epithelia of 6-day-old embryonic chickens. The results indicate that delta-crystallin, c-myc, p53, and c-fos are actively transcribed in these cells, while c-myb, N-ras, and c-mil are not transcribed at detectable levels. PMID: 2645183 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 421: Anticancer Res. 1989 Mar-Apr;9(2):449-52. Amplification of oncogenes in lung carcinoma grafted in nude mice. Chauvin C, Jacrot M, Riondel J, Brambilla E, Foote AM, Brambilla C, Benabid AL. Departement de Biophysique, UFR de Medecine de Grenoble, La Tronche, France. Seven lung carcinomas were grafted on nude mice and continuously propagated as in vivo models on which the amplification of 9 oncogenes (N-myc, v-erb A, v-abl, v-sis, c-myc, c-myb, v-Ha-ras, c-Kiras, and v-scr) was studied by Southern blot hybridization. Only c-myc was amplified (20 copies) in an adenocarcinoma. The presence of 2 bands at 9 kb and 6.6 kb in addition to the normal 12.7 kb in EcoR1 digested DNAs suggested a polymorphism of the c-myc gene in this tumor. The other 8 oncogenes were not amplified in this tumor. The 5 small cell lung carcinomas of this study did not show any amplification of any of the 9 oncogenes tested. PMID: 2568771 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 422: Blood. 1989 Feb 15;73(3):782-6. c-myb but not c-myc suppresses the hemin-induced nonterminal expression of hemoglobin by murine erythroleukemia cells. Prochownik EV. University of Michigan, Ann Arbor 48109. Clonal lines of Friend murine erythroleukemia (F-MEL) cells have been generated following transfection with c-myc or c-myb expression plasmids. These clones produce high levels of abnormally regulated proto-oncogene transcripts and fail to terminally differentiate in the presence of dimethyl sulfoxide. To determine the relative levels at which the two proto-oncogenes might exert their inhibitory effects, we asked whether these clones could express differentiated functions in the absence of terminal differentiation. It was found that exposure of c-myc-transfected cells to hemin allows for the induction of hemoglobin, whereas c-myb-transfected cells were refractory to hemin induction. It thus appears that c-myb exerts a more globally suppressive effect on F-MEL-differentiated functions than does c-myc and may prevent the expression of those events that can otherwise be dissociated from the terminally differentiated state. PMID: 2644989 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 423: Blood. 1989 Feb;73(2):431-4. Tiazofurin induction of mouse erythroleukemia cell hemoglobin production in the absence of commitment or changes in protooncogene expression. Sherman ML, Shafman TD, Colman MS, Kufe DW. Laboratory of Clinical Pharmacology, Dana-Farber Cancer Institute, Boston, MA 02115. Tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide, NSC 286193), is a synthetic nucleoside inhibitor of inosine monophosphate dehydrogenase and blocks guanine nucleotide biosynthesis. In the present study, we examined the effects of tiazofurin on mouse erythroleukemia (MEL) cell differentiation and protooncogene expression. Tiazofurin induced hemoglobin production in MEL cells in a concentration-dependent manner, as measured by an increase in benzidine staining. Northern blot analysis of MEL cells treated with 7 mumol/L tiazofurin demonstrated accumulation of both alpha- and beta-globin RNA transcripts. This induction of differentiation was blocked by the presence of exogenous guanosine (100 mumol/L). In contrast to the down-regulation of c-myc and c-myb RNA in MEL cells induced by dimethyl sulfoxide (DMSO) or hexamethylene bisacetamide (HMBA), there was no detectable change in levels of these transcripts after tiazofurin treatment. Furthermore, MEL cells induced by tiazofurin did not commit to terminal differentiation. These results suggest a role for guanine nucleotides, at least in part, in the regulation of MEL cell differentiation. PMID: 2917182 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 424: Nippon Ketsueki Gakkai Zasshi. 1989 Feb;52(1):32-7. Southern blot analysis of Bcr, N-ras, H-ras, c-myc and myb proto-oncogenes in blast crisis of chronic myelogenous leukemia. Naoe T, Doi S, Yamanaka K, Naito K, Nitta M, Yamada K. Proto-oncogenes were studied by Southern blotting in 12 patients with chronic myelogenous leukemia in blast crisis (CML). Cytogenetically, all cases had Philadelphia (Ph1) chromosome and 4 had additional chromosomal abnormalities including +8, +19, i(17q), double Ph1. The bcr gene was rearranged in all cases and the region of breakage points were located in the 5.8 kb Bgl II-Bam HI fragment of bcr. In a case with double Ph1 the breakage points of bcr were thought to be different from each other. We analyzed other proto-oncogenes (N-ras, H-ras, c-myc and myb) by Southern blotting, but did not find any abnormalities. PMID: 2741649 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 425: 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] --------------------------------------------------------------- 426: Biochim Biophys Acta. 1989 Jan 23;1007(1):99-108. Cyclic-AMP-induced c-fos expression and its relevance to differentiation of a transformed mast cell line. Goulding MD, Ralph RK. Department of Cellular and Molecular Biology, University of Auckland, New Zealand. The effects of cyclic AMP on expression of the oncogenes c-myc, c-myb and c-fos in murine P815 mastocytoma cells were examined in relation to growth and differentiation. Induction of differentiation in mastocytoma cells by cyclic AMP was accompanied by a rapid increase in c-fos expression. Cyclic AMP induced stable expression of c-fos mRNA by increasing c-fos transcription 4-5-fold and slightly increasing the stability of c-fos mRNA. However, a high level of c-fos expression was not essential for differentiation of two temperature sensitive-mutant P815 cell lines, as c-fos mRNA did not increase in differentiating temperature-sensitive P815 cells. These results do not support an essential role for c-fos expression in the differentiation of mast cells. Although c-myc expression was lower after growth arrest by cyclic AMP, this decrease did not correlate with growth inhibition by cyclic AMP, since c-myc expression decreased only after cells had started to arrest in G1 phase. PMID: 2535780 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 427: Oncogene. 1989 Jan;4(1):105-8. Proto-oncogene abnormalities in human breast cancer: c-ERBB-2 amplification does not correlate with recurrence of disease. Zhou DJ, Ahuja H, Cline MJ. Department of Medicine, UCLA, 90024. The incidence of c-ERBB-2 amplification in breast cancers and its usefulness as a predictor of tumor recurrence after treatment have been subjects of controversy (Ali et al., 1988, Slamon et al., 1987). We re-examined this subject by analysing 157 primary and 14 metastatic breast cancers with c-ERBB-2 and 18 other molecular probes as controls. Five proto-oncogenes were found to be occasionally amplified in primary breast cancers: c-ERBB-2 (11%), c-MYB (3%), c-RAS-Ki (3%), INT-2 (4%) and c-MYC (6%). No statistically significant correlation between amplification of c-ERBB-2 and recurrence of tumors was observed. The only significant correlation observed was between early recurrence of advanced (stage III) tumors and amplification of one or another of the above five proto-oncogenes. We conclude that breast cancer utilize multiple genetic mechanisms in their progression and metastasis, and that analysis of c-ERBB-2 alone is not a useful guide. PMID: 2915899 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 428: Leuk Res. 1989;13(1):53-64. Oncogene expression in Rauscher murine leukemia virus induced erythroid, myeloid and lymphoid cell lines. de Both NJ, van der Feltz MJ, Mooren A, Vermaas D, Klaassen P, Rhijnsburger EH, Kranendonk-Odijk ME. Department of Pathology, Medical Faculty, Erasmus University, Rotterdam, The Netherlands. A comparative study on the expression of nuclear and cytoplasmic oncogenes was carried out using the Northern blotting technique, in Rauscher virus induced primary leukemias and the more malignant transformed cell lines derived from them. The latter grow permanently in vitro. Hyperplastic spleens obtained from mice recovering from anemia were analysed as controls. In addition to the detection of mRNAs, Southern blotting was carried out to observe whether rearrangement or amplification of oncogenes had occurred. The results show that the nuclear oncogenes c-myc, c-myb and p53 are strongly expressed in leukemic tissue, whereas c-fos transcripts show a much weaker hybridization. The expression of two of these oncogenes, c-myc and c-myb was followed during differentiation in myeloid leukemic cells and showed a gradual decrease when compared with the actin gene, which is constitutively transcribed. A large number of cytoplasmic oncogenes is expressed in the leukemic cells lines, i.e. c-abl, c-fms, c-fes, c-src, c-ros, c-H-ras, c-K-ras and N-ras. Of these, transcripts coding for c-abl and c-src were absent in blast cells of acute erythroid leukemias. Transcripts coding for c-erb, c-mos and c-sis could also not be detected. A number of putative oncogenes which are reported to play a role in Moloney and Friend virus induced leukemias for instance pim-1, fis-1, fim-1 and fim-2 were also used for screening. Only expression of pim-1 in Rauscher virus induced myeloid leukemic cells and in primary acute erythroid leukemias could be observed. At the DNA level no rearrangement or amplification of any of the oncogenes investigated could be detected. The results show that a number of oncogenes are expressed simultaneously in the same leukemic tissue or cell lines. It therefore seems likely that the presence of transcripts of different oncogenes is associated with the progression of leukemia, but is not the primary cause of leukemogenesis or of the transformation of these cells into established cell lines. PMID: 2915575 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 429: Blood. 1989 Jan;73(1):255-62. Protooncogene expression and the clinical characteristics of acute nonlymphocytic leukemia: A Leukemia Intergroup pilot study. Preisler HD, Raza A, Larson R, LeBeau M, Browman G, Goldberg J, Grunwald H, Volger R, Verkh L, Singh P, et al. Department of Hematologic Oncology, Roswell Park Memorial Institute, NY. Northern blot analysis was used to assess the level of expression of five protooncogenes and histone H3 in the bone marrow cells of patients with acute nonlymphocytic leukemia (ANLL). The relationship between the level of gene expression and the clinical characteristics of the disease and response to therapy was studied. The levels of expression of c-myc and c-myb are weakly correlated and are unrelated to French-American-British (FAB) type of ANLL. The levels of expression of c-fms, c-fes, and c-fos are highly correlated with each other and are highest in leukemia with a monocytic component (c-fms v FAB = .71, c-fes v FAB = .75). High levels of c-myc expression are associated with a high probability of not responding to remission induction therapy (P = .004). The converse is true for c-fms expression levels. High levels of expression of c-myc or c-myb are associated with short remissions (P = .059 and .065, respectively), perhaps because they are associated with a high capacity for leukemic cell self-renewal and/or an inability of leukemic cells to differentiate in response to chemotherapy. PMID: 2910363 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 430: EMBO J. 1989 Jan;8(1):175-81. Molecular cloning of the chicken myelomonocytic growth factor (cMGF) reveals relationship to interleukin 6 and granulocyte colony stimulating factor. Leutz A, Damm K, Sterneck E, Kowenz E, Ness S, Frank R, Gausepohl H, Pan YC, Smart J, Hayman M, et al. European Molecular Biology Laboratory, Heidelberg, FRG. Normal as well as retrovirally transformed avian myeloid precursor cells require the colony stimulating factor cMGF for their survival, proliferation and colony formation in vitro. cMGF has been shown to be a glycoprotein which is active in the picomolar concentration range. Co-expression of kinase type oncogenes in v-myb or v-myc transformed myeloid cells induces cMGF expression and confers factor independence via an autocrine mechanism. Here we describe the molecular cloning of cMGF from a myeloblast cDNA library and show that it is a 201 amino acid residue secretory protein which is modified by signal peptide cleavage and glycosylation during translocation into the lumen of membrane vesicles. A bacterially expressed trpE-cMGF fusion protein induces proliferation of E26 transformed myeloblasts in a cMGF bioassay suggesting that glycosylation is not absolutely necessary for biological activity. Sequence comparison reveals that cMGF is distantly related to G-CSF and IL-6. PMID: 2785450 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 431: Mol Carcinog. 1989;2(1):27-33. Molecular analysis of DNA isolated from the different stages of x-ray-induced transformation in vitro. Krolewski B, Little JB. Laboratory of Radiobiology, Harvard School of Public Health, Boston, Massachusetts 02115. A major challenge in radiation carcinogenesis is to identify the cellular gene or genes involved in initiating the process. We examined the transforming activities of DNAs obtained from C3H10T1/2 cells during x-ray-induced morphological transformation. DNAs extracted from mass cultures of 10T1/2 cells at different times after irradiation with 600 rad and from type III-transformed foci were transfected into NIH 3T3 cells. The results indicate that certain oncogenes are activated beginning 3 wk after irradiation, well before the appearance of macroscopically visible transformed foci. For DNA isolated from x-ray-transformed 10T1/2 cells (type III foci), the frequencies of transfection were 0.003-0.11 foci/microgram of genomic DNA with NIH 3T3 cells and 0.004-0.04 foci/microgram genomic DNA using 10T1/2 cells as recipients. Southern blot analysis of DNAs obtained from 23 primary transfectants and from 23 x-ray-transformed cell lines indicated no gross rearrangements or amplification of any of the 14 oncogenes screened (v-Ha-ras, v-Ki-ras, N-ras, v-myc, v-raf, v-src, v-fes, v-abl, v-mos, v-erbA, v-erbB, v-myb, v-fos, v-sis). This suggests that x-irradiation may activate as yet unidentified oncogenes. The occurrence of positive transfection 3 wk after irradiation is discussed in terms of the hypothesis that transformation may not occur as a direct consequence of the exposure to x-rays but develops as a rare event in the progeny of the irradiated cells at some later time, as a consequence of the delayed activation of certain genes. PMID: 2730762 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 432: Haematol Blood Transfus. 1989;32:343-6. c-myc and c-myb oncoproteins during induced maturation of human myeloid and erythroid leukaemic lines. Bains MA, Pedrazzoli P, Hoy TG, Jacobs A. Department of Haematology, University of Wales College of Medicine, Cardiff, UK. PMID: 2696685 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 433: Crit Rev Ther Drug Carrier Syst. 1989;5(4):229-61. The molecular basis of immune cytokine action. Farrar WL, Ferris DK, Harel-Bellan A. Laboratory of Molecular Immunoregulation, Frederick Cancer Research Facility, Maryland. The polypeptide hormones governing the proliferation and differentiation of the mature immune system and hematopoiesis are collectively referred to as lymphokines. We have examined a number of biochemical and molecular events stimulated by several unique lymphokines which exhibit proliferative activity on lymphoid and myeloid cell lines. Interleukin-2 (IL-2) and several members of the colony-stimulating factors (IL-3, G-CSF, and GM-CSF) stimulate similar patterns of cellular phosphorylation including the prominent phosphorylation of a 68-kDa substrate present in numerous distinct lineage cell lines. The 68-kDa substrate is phosphorylated by protein kinase C on threonine residues and is primarily cytosolic. Another kinase system activated by either physiological ligand or synthetic diacylglycerol phosphorylated the 40S ribosomal protein in a dose-dependent manner. The increased phosphorylation of S6 protein was associated with enhanced chain elongation in vitro. The kinase responsible for the in situ phosphorylation, however, was not protein kinase-C (PK-C) but another physicochemically distinct Mg2+-dependent enzyme (termed S6 kinase). These studies suggested that, although PK-C was activated by diacylglycerol, another kinase, S6 kinase, was the effector enzyme involved in the phosphorylation of the 40S protein. IL-2 and all other CSFs tested stimulated the transcription of the nuclear protooncogenes c-fos, c-myc, and c-myb. In addition, ornithine decarboxylase mRNA accumulation was also stimulated. Phorbol esters also stimulated similar gene expression; however, cyclic AMP analog inhibited phorbol ester or ligand-induced c-myc expression and ODC mRNA accumulation. Cyclic AMP agonists are antiproliferative to all the growth factors tested. We have constructed complementary oligonucleotides, "antisense", against c-fos, c-myc, and other structural genes induced by the growth factors. Such antisense oligomers were capable of selectively deleting protein expression of the respective gene products and inhibited the biological action of the growth factors. Publication Types: Review PMID: 2653649 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 434: Oncogene. 1989 Jan;4(1):115-8. Association of v-myc protein with chromatin. Klempnauer KH. Zentrum fur Molekulare Biologie, Universitat Heidelberg, Federal Republic of Germany. The subnuclear distribution of proteins encoded by v-myb and v-myc was analysed in a cell-line of AMV-transformed chicken myeloblasts superinfected by the myc-containing retrovirus MC29. p45v-myb and p110gag-myc, co-expressed in these cells, were released in similar fashion when nuclei were treated with salt or DNAase. Analysis of nucleoprotein complexes extracted from nuclease-treated nuclei shows that p45v-myb and p110gag-myc are associated with a chromatin fraction of enhanced nuclease sensitivity. v-myb and v-myc proteins thus share the same subnuclear location and apparently interact directly with the cellular DNA. PMID: 2644610 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 435: Cancer Commun. 1989;1(3):191-7. Effects of tiazofurin on globin and proto-oncogene expression in K562 erythroleukemia cells. Kharbanda SM, Miyazaki K, Takeyama H, Sherman ML, Spriggs DR, Carney WP, Kufe DW. Laboratory of Clinical Pharmacology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115. Tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide, NSC 286193) is a synthetic nucleoside inhibitor of inosine monophosphate dehydrogenase. This agent has recently been shown to induce differentiation of human leukemia cell lines. In the present study, we have monitored the effects of tiazofurin on differentiation and proto-oncogene expression in K562 erythroleukemia cells. Tiazofurin induced K562 cell hemoglobin production in a concentration-dependent manner. This induction of a differentiated phenotype was also associated with a loss of proliferative capacity. In contrast to the reversible effects of hemin on induction of K562 cell hemoglobin synthesis, the effects of tiazofurin were irreversible. Northern blot analysis of K562 cells treated with 10 microM tiazofurin demonstrated the accumulation of alpha- and gamma-globin mRNA. The results also demonstrate that there was little if any effect of tiazofurin on levels of c-myc, c-myb, or c-abl mRNA. Furthermore, there were no detectable changes in Ki-ras, Ha-ras or N-ras expression at the mRNA and protein levels in tiazofurin-treated K562 cells. These findings suggest that tiazofurin induces changes in levels of globin transcripts but has little if any effect on c-myc, c-myb, c-abl, or c-ras gene expression in K562 cells. PMID: 2639729 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 436: 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] --------------------------------------------------------------- 437: Virchows Arch B Cell Pathol Incl Mol Pathol. 1989;57(5):285-90. Amplification of epidermal growth factor receptor (EGFR) gene and oncogenes in human gastric carcinomas. Yoshida K, Tsuda T, Matsumura T, Tsujino T, Hattori T, Ito H, Tahara E. First Department of Pathology, Hiroshima University School of Medicine, Japan. DNAs from 37 human gastric carcinomas and seven lymph node metastases were analyzed for alterations of the epidermal growth factor receptor (EGFR) gene and oncogenes by the Southern blot hybridization method. The probes used were EGFR gene, c-Ha-ras, v-Ki-ras, N-ras, c-myc, v-myb, v-fos, c-erbB-2, v-erbA, v-abl and v-fes. Amplification of the EGFR gene was detected in only one poorly differentiated adenocarcinoma. Amplifications of c-myc gene and c-erbB-2 gene were each observed in two well differentiated adenocarcinomas. One of these tumors had coamplification of c-erbB-2 and c-erbA genes but there were no amplifications nor rearrangements of other oncogenes. The poorly differentiated adenocarcinom with amplified EGFR gene also showed enhanced expression of EGFR gene by Northern blot analysis and additionally had strong synchronous immunoreactivity for EGFR and EGF. PMID: 2570489 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 438: Br J Cancer. 1989 Jan;59(1):76-80. Cellular protoonocogenes are infrequently amplified in untreated non-small cell lung cancer. Slebos RJ, Evers SG, Wagenaar SS, Rodenhuis S. Department of Experimental Therapy, Netherlands Cancer Institute, Amsterdam. To examine a potential contribution of protooncogene abnormalities other than point-mutational activation of the K-ras protooncogene in the classification of non-small cell lung cancer, amplification of cellular protooncogenes was studied in 47 lung tumour specimens obtained at thoracotomy and in four lung tumour cell lines. The primary tumours included 21 adenocarcinomas, nine large-cell carcinomas, 13 epidermoid carcinomas, one carcinoid and three metastases of primaries outside the lung. The copy numbers per haploid genome of 11 protooncogenes in every tumour sample were determined: H-ras, K-ras, N-ras, c-myc, N-myc, L-myc, erbB, mos, myb, ncu (erbB-2) and ral amplifications. The c-myc gene was amplified 5-7-fold in two adenocarcinomas, the H-ras gene 3 5-fold in one adenocarcinoma, while the K-ras and the neu gene were amplified in lung metastases from a colorectal and a breast cancer primary respectively. None of the tumours with an amplified protooncogene simultaneously harboured a mutationally activated K-ras gene. We conclude that amplification of the investigated protooncogenes is a rare event in non-small cell lung cancer. In view of the two c-myc amplifications detected, a systematic study of c-myc expression levels in non-small cell lung cancers appears worthwhile. PMID: 2547415 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 439: Oncogene. 1989 Jan;4(1):45-50. Expression of p64c-myc and neuroendocrine properties define three subclasses of small cell lung cancer. Bepler G, Bading H, Heimann B, Kiefer P, Havemann K, Moelling K. Philipps University Medical Center, Department of Internal Medicine, Marburg, Federal Republic of Germany. Twelve human small cell lung cancer (SCLC) cell lines and 6 non-SCLC cell lines were analysed with respect to expression of the c-myc, c-myb, and c-raf1 protooncogenes at the protein level. Analysis of p64c-myc protein expression in 12 SCLC cell lines resulted in the observation that it is present at high levels not only in cells with low, but also in those with moderate neuroendocrine differentiation. Neuroendocrine differentiation was based on parameters such as growth rate, colony formation, L-Dopa decarboxylase (DDC) activity, bombesin, and neurotensin described before. Surprisingly, in two cell lines with low neuroendocrine differentiation but without c-myc protein expression (SCLC-86M1 and NCI-H526) p75c-myb expression was observed which may therefore be able to substitute for the p64c-myc protein. Analysis of p74c-raf1 expression did not result in correlation with any growth or differentiation parameter since it was expressed at low levels in 11 out of 12 cases. We conclude that SCLC in vitro can be classified in three rather than two previously defined subclasses. In addition to the classic subclass with slow growth, high neuroendocrine differentiation, and absent or very low p64c-myc expression and the variant subclass with fast growth, absent to very low neuroendocrine differentiation, and high p64c-myc expression, we suggest a third subclass designated as transitional with moderate growth, moderate neuroendocrine differentiation, and high p64c-myc expression. Data on a small number of non-SCLC cell lines tested showed that high levels of p64c-myc correlate with high in vitro growth rates. This indicates that high p64c-myc levels may be associated with high proliferative activity, and lack of differentiation in lung cancer in general. The p74c-raf1 protein was found in all non-SCLC cell lines. Whether this classification of SCLC cell lines is applicable to SCLC in vivo remains to be determined. PMID: 2536917 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 440: J Cancer Res Clin Oncol. 1989;115(2):118-28. Benzo[a]pyrene-diol-epoxide-induced anchorage-independence in diploid human fibroblasts. Analysis of cellular protooncogenes. Stevens CW, Brondyk WH, Fahl WE. McArdle Laboratory for Cancer Research, University of Wisconsin, Madison 53706. Treatment of diploid human fibroblasts with stereoisomeric benzo[alpha]pyrene anti and syn diol epoxides has been shown to induce anchorage-independent clones of cells with a dose dependence and frequency [(0.5-12) X 10(-4)] not significantly different from mutations at the hypoxanthine-guanine phosphoribosyltransferase locus [(1-8) X 10(-4)] in these cells. The majority of the anchorage-independent clones that were picked retained their mutagen-induced, anchorage-independent phenotype through at least 20 generations of expansion in monolayer culture. No variant cells showing extended life-span were detected among survivors in any of the mutagen treatment groups (less than 1.6 X 10(-7) frequency). Extensive analysis of a pool of 15 cellular protooncogenes (Ha-ras, Ki-ras, N-ras, mos, fos, fes, myc, abl, sis, myb, erbA, erbB, src, raf, N-myc), using Southern and northern blot analysis, was done to determine whether mutagen-induced rearrangement, amplification or overexpression of any of these genes was responsible for the mutagen-induced, anchorage-independent phenotype. We found no evidence that the genomic arrangement or expression level of any of these genes had been altered, thus indicating that an alternative form of mutation, or an alternative gene not included in this screening was responsible for the mutagen-induced, anchorage-independent phenotype. PMID: 2497101 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 441: Oncogene Res. 1989;4(4):311-8. Expression of cellular oncogenes: unrearranged c-myc gene but altered promoter usage in radiation-induced thymoma. Bandyopadhyay SK, D'Andrea E, Fleissner E. Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021. Expression of eleven oncogenes was analyzed in thymomas induced by X-rays in the BALB/c strain of mice. H-, K-, N-ras, c-myc, c-myb, and c-abl genes were consistently expressed in thymomas, as well as in normal, age-matched thymus. Only c-myc transcription appeared to be altered in thymomas: a 1.5-3-fold elevated expression of c-myc was found in 42% of the thymomas tested. An altered ratio of two normal promoters, P1 and P2, of the c-myc gene has also been observed in 6 samples out of 15 tested. In one sample, expression from only the P2 promoter was found. A change in DNA sequence to the 5' side of this promoter was detected in an RNAase cleavage assay; this could have disrupted transcription from the P1 promoter. No other structural alteration has been detected within approximately 1800 bases upstream or 700 bases downstream from the 1st exon including exon 1 of the c-myc gene. With the exception of the one sample described, the results of RNAase cleavage assays, as well as Southern blotting of the c-myc gene, show that the structural alteration of this region of c-myc is not generally associated with radiation-induced thymomas in this strain of mice. PMID: 2475843 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 442: Nature. 1988 Dec 22-29;336(6201):719. Tryptophans in myb proteins. Anton IA, Frampton J. Publication Types: Letter PMID: 3060725 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 443: Leukemia. 1988 Dec;2(12 Suppl):160S-166S. Expression of oncogenes and cell cycle related genes in acute and chronic leukemias. Ferrari S, Calabretta B, Selleri L, Ceccherelli G, Torelli G, Torelli U. Second Medical Clinic, University of Modena, Italy. The authors have assayed the level of expression of several cell-cycle related genes in several populations of circulating myeloid leukemic blast cells. The genes explored included oncogenes such as c-myc, c-myb, p53, and cell-cycle-related genes such as vimentin, calcyclin, ornithine decarboxylase (ODC) and histone H3. Particular attention was given to analysis of the relationship existing between the mRNA levels of the histone H3 gene, which is expressed specifically in the S phase of the cell cycle, and the levels of other genes that are expressed in different stages of the G1 phase. Remarkable differences were observed among the different cases indicating that a differential expression of cell-cycle-related genes characterizes many acute leukemias. This differential expression is reflected in an altered ratio among G1-related genes and the H3 histone gene. The large fraction of leukemic cells which does not express histone H3 and therefore is functionally noncycling, shows a heterogeneous pattern of G1-related gene expression. This reflects the inability of most leukemic cells to progress through the G1 phase into the S phase of the cell cycle. This inability represents an abnormality of the cell cycle. It is concluded that the study of the expression of cell-cycle genes and protooncogenes in in understanding how leukemic cells enter a state of proliferation arrest, which appears to occur in a large fraction of leukemic cells. PMID: 3199878 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 444: Proc Natl Acad Sci U S A. 1988 Dec;85(23):8900-4. Down-regulation of c-myb gene expression is a prerequisite for erythropoietin-induced erythroid differentiation. Todokoro K, Watson RJ, Higo H, Amanuma H, Kuramochi S, Yanagisawa H, Ikawa Y. Tsukuba Life Science Center, Institute of Physical and Chemical Research, Ibaraki, Japan. The role of nuclear protooncogenes during erythroid cell differentiation was examined by transfecting exogenous c-fos and c-myb genes into mouse erythroleukemia cells, which can be induced to differentiate either with erythropoietin (Epo) or dimethyl sulfoxide. Expression of exogenous c-myb or c-fos oncogene completely inhibited Epo-induced erythroid differentiation but only partially inhibited dimethyl sulfoxide-induced differentiation. Normally Epo-induced differentiation leads to a drastic decline of c-myb mRNA levels and an increase of c-myc transcripts in the early stage of differentiation. Cells expressing exogenous c-fos gene, however, maintained high levels of c-myb mRNA after Epo treatment. This high level of c-myb transcripts was found to be due to block of transcription shutoff (or transcriptional activation) rather than to mRNA stabilization. It is concluded that the down-regulation of endogenous c-myb gene expression is a prerequisite for commitment of Epo-induced erythroid differentiation and that expression of c-myb gene may be indirectly regulated by c-fos gene product. We also concluded that early down-regulation of c-myc gene expression is not essential for erythroid differentiation and that gene regulation of chemically induced erythroid differentiation may differ from that of Epo-induced differentiation. PMID: 3194397 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 445: FASEB J. 1988 Dec;2(15):3043-53. 1,25(OH)2-vitamin D3 receptors: gene regulation and genetic circuitry. Minghetti PP, Norman AW. Department of Biochemistry, University of California, Riverside 92521. Our understanding of how vitamin D mediates biological responses has entered a new era. It is now clear that the bulk of the biological responses supported by vitamin D occur as a consequence of its metabolism to its daughter metabolite 1 alpha,25-dihydroxyvitamin D3 (a steroid hormone). The fact that 1,25(OH)2D3 receptors are ubiquitous in tissue distribution opens the possibility for unforeseen biological functions of the vitamin D endocrine system. For example, 1,25(OH)2D3 serves as an immunoregulatory hormone and a differentiation hormone besides its classical role in mineral homeostasis. The avian 1,25)OH)2D3 receptor has recently been cloned and shown to be a member of the nuclear transacting receptor family that includes estrogen, progesterone, glucocorticoid, thyroxine (T3), aldosterone, and retinoic acid receptors. We have compiled an extensive number of RNA polymerase II-transcribed genes that are regulated by 1,25(OH)2D3. Classification of these genes on functional grounds identifies and formulates the several genetic circuits or biochemical systems in which 1,25(OH)2D3 plays an essential regulatory role. These systems include genes that govern oncogene and lymphokine expression as well as those involved in mineral homeostasis, vitamin D metabolism, and regulation of a set of replication-linked genes (c-myc, c-myb, and histone H4), which are critical for rapid cellular proliferation. An integrated analysis of the combinations of genetic circuits regulated by 1,25(OH)2D3 suggests that they may be collectively tied to a DNA replication-differentiation switch. Publication Types: Review Review, Tutorial PMID: 2847948 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 446: J Biol Chem. 1988 Nov 25;263(33):17615-20. Regulation of pim and myb mRNA accumulation by interleukin 2 and interleukin 3 in murine hematopoietic cell lines. Dautry F, Weil D, Yu J, Dautry-Varsat A. Laboratoire d'Oncologie Moleculaire, Centre National de la Recherche Scientifique, UA 1158, Institut Gustave Roussy, France. We have studied the mRNA accumulation of pim and myb genes in two interleukin 2- (IL2-)dependent, CTLL-2 and B6.1, and one IL3-dependent, FDC-P2, murine hematopoietic cell lines. To be able to dissociate the IL2 response from the phenomenon of lymphocyte activation, we used cell lines constitutively expressing the high affinity IL2 receptor. Deprivation of IL2 for 16 h led to an accumulation of CTLL-2 cells in G0/G1, and stimulation with IL2 induced a progression in S phase after 10 h. An increased accumulation of pim mRNA was observed in all cases in response to IL2 or IL3. This regulation did not require de novo protein synthesis and was, in CTLL-2 cells, mostly at the transcriptional level. Expression of myb was more complex: in CTLL-2 and FDC-P2 it is high and constitutive, while in B6.1 it is low and induced by IL2. This difference in myb regulation correlates with the higher level of myb expression in immature cells, as only B6.1 is functionally mature. Furthermore, it shows that transcription of myb does not affect the control of the cell cycle by the growth factors IL2 and IL3. These studies demonstrate that pim belongs to the small group of protooncogenes that can be induced during the primary response to growth factors (fos, myc, and myb) and that constitutive expression of myb, at least at the RNA level, is not sufficient to abrogate the growth factor requirement of hematopoietic cell lines. PMID: 3263373 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 447: Mol Cell Biol. 1988 Nov;8(11):4700-6. A short-lived nuclear phosphoprotein encoded by the human ets-2 proto-oncogene is stabilized by activation of protein kinase C. Fujiwara S, Fisher RJ, Bhat NK, Diaz de la Espina SM, Papas TS. Laboratory of Molecular Oncology, National Cancer Institute, Frederick, Maryland 21701-1013. The human ets-2 gene is a homolog of the v-ets oncogene of the E26 virus and codes for a 56-kilodalton nuclear protein. The ets-2 protein is phosphorylated and has a rapid turnover, with a half-life of 20 min. When human lymphocytic CEM cells were treated with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), the level of the ets-2 protein was quickly elevated 5- to 20-fold. This effect of TPA was mimicked by a synthetic diacylglycerol, 1-oleoyl-2-acetyl glycerol, and was blocked by the protein kinase C inhibitor H7, indicating that protein kinase C is involved in the induction. The increase in the ets-2 protein was due to stabilization of the protein, because the protein had a half-life of more than 2 h in the presence of TPA and the ets-2 mRNA level did not increase significantly upon TPA treatment. The protein synthesis inhibitor cycloheximide enhanced the effect of TPA on the ets-2 protein and could itself slow turnover of the protein. Properties of the ets-2 protein, such as nuclear localization, phosphorylation, rapid turnover, and response to protein kinase C, indicate that this protein belongs to a group of oncogene proteins which are generally thought to have regulatory functions in the nucleus (e.g., myc, fos, myb, and p53). Our results suggest that protein kinase C, either directly or indirectly, regulates the level of the ets-2 protein by posttranslational mechanisms. PMID: 3062367 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 448: Leukemia. 1988 Nov;2(11):749-53. Suppression of c-myc and c-myb expression in myeloid cell lines treated with recombinant tumor necrosis factor-alpha. Schachner J, Blick M, Freireich E, Gutterman J, Beran M. Department of Hematology, M. D. Anderson Hospital and Tumor Institute, Houston, TX 77030. Proto-oncogenes are thought to be involved in cellular differentiation and proliferation. Tumor necrosis factors (TNFs) are specific cytokines that have cytostatic and cytotoxic effects in vitro against a wide range of human tumor cells. We have previously demonstrated that recombinant TNFs (rTNFs) have an antiproliferative effect on certain human leukemic cell lines (HL-60, KBM3, KBM5) and no effect on others (K562). To study the possible role of the c-myc and c-myb oncogenes in this antiproliferative effect of TNF, we examined their expression in cell lines HL-60, KBM3, KBM5, and K562 before and after incubation with rTNF-alpha. Expression of c-myc and c-myb was elevated in all cell lines prior to incubation with rTNF-alpha. In the sensitive cell lines HL-60, KBM5, and KBM3 expression of c-myc and c-myb decreased rapidly 8-, 16-, and 4-fold, respectively, by 24 hr. K562 cells, insensitive to rTNF-alpha, exhibited no change in c-myc or c-myb expression over 24 hr. These studies demonstrated that down-regulation of c-myc and c-myb expression were associated with antiproliferative effects of rTNF-alpha on these cell lines. PMID: 3054350 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 449: J Immunol. 1988 Nov 1;141(9):3234-40. Changes in gene expression associated with IFN-beta and IL-2-induced augmentation of human natural killer cell function. Kornbluth J, Hoover RG. Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19104-6082. NK function can be augmented by a variety of agents, including the cytokines IL-2 and IFN. The mechanisms associated with IL-2- and IFN-mediated augmentation of NK function are largely unknown. In order to learn more about the regulation of NK activity, we have studied changes in gene expression that occur upon treatment of a cloned line of NK cells (NK 3.3) with rIL-2 and rIFN-beta. Both IL-2 and IFN-beta induced rapid augmentation of lysis mediated by NK 3.3, which was significant within 1 h, peaked at 6 h of treatment, and declined by 12 h. This enhancement of lytic function was independent of proliferation and associated with a corresponding increase in steady state levels of RNA coding for both the nuclear proto-oncogene c-myb and for the IL-2R. These changes were specific in that RNA levels of another nuclear proto-oncogene, c-myc, were increased by IL-2 but not by IFN-beta, whereas HLA class I RNA levels were relatively unchanged by either IL-2 or IFN-beta treatment. Treatment of NK 3.3 with the combination of IL-2 and IFN enhanced both lysis and c-myb expression in an additive fashion. These findings suggest that c-myb may play a regulatory role in the cytolytic activity of NK cells. PMID: 3049820 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 450: Cancer Res. 1988 Nov 1;48(21):5965-8. Effects of tiazofurin on protooncogene expression during HL-60 cell differentiation. Kharbanda SM, Sherman ML, Spriggs DR, Kufe DW. Laboratory of Clinical Pharmacology, Dana-Farber Cancer Institute, Boston, MA 02115. The synthetic nucleoside analogue, tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide, NSC 286193) is an inhibitor of the enzyme inosine monophosphate (IMP) dehydrogenase and depletes guanine nucleotide pools. In the present study, we have monitored the effects of tiazofurin on human HL-60 promyelocytic cell differentiation and protooncogene expression. Tiazofurin (10 microM) induced a more differentiated HL-60 cell phenotype as determined by histochemical staining and decreased myeloperoxidase gene expression. This induction of differentiation was associated with a loss of proliferative capacity and decreases in clonogenic survival. The results also demonstrate that tiazofurin induces a down-regulation of c-myc mRNA levels. In contrast, there was no detectable change in the level of 3.8-kilobase c-myb transcripts. Furthermore, treatment of HL-60 cells with tiazofurin resulted in the appearance of an additional c-myb mRNA with an apparent size of 3.3 kilobases. The addition of guanosine to tiazofurin-treated HL-60 cells prevented the down-regulation of c-myc transcripts and also inhibited induction of the 3.3-kilobase c-myb transcript. Moreover, this additional transcript was not detected during induction of HL-60 cells by dimethyl sulfoxide, tumor necrosis factor, and retinal, but was induced by another IMP dehydrogenase inhibitor, mycophenolic acid. These results suggest a role for guanosine ribonucleotides in the regulation of c-myc and c-myb gene expression during HL-60 cell differentiation. The results also suggest that changes in c-myb expression can be dissociated from that of c-myc and induction of myeloid differentiation. PMID: 2901907 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 451: Biosci Rep. 1988 Oct;8(5):415-9. Proto-oncogene homologous sequences in the sea urchin genome. Mifflin D, Robinson JJ. Department of Biochemistry, Memorial University of Newfoundland, St John's, Canada. Using probes specific for several oncogenes/proto-oncogenes we have performed gel blot hybridization analyses of genomic DNA isolated from the sea urchin Strongylocentrotus droebachiensis. Probes prepared from v-erbB, v-myc, c-myb and v-fps were found to hybridize with discrete fragments of HindIII digested genomic DNA. In contrast, probes prepared from v-abl, v-fos, v-sis, v-src, and v-mos either hybridized with multiple fragments, indicating non-specific binding, or failed to hybridize at all above background levels. These results clearly demonstrate the presence of proto-oncogene homologous sequences in the sea urchin genome. PMID: 2852975 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 452: 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] --------------------------------------------------------------- 453: Cancer. 1988 Sep 15;62(6):1171-8. Effect of differentiation-inducing agents on oncogene expression in a chronic myelogenous leukemia cell line. Eisbruch A, Blick M, Evinger-Hodges MJ, Beran M, Andersson B, Gutterman JU, Kurzrock R. Department of Oncology, Tel-Hashomer Hospital, Israel. K562 is a Philadelphia (Ph) chromosome-positive chronic myelogenous leukemia (CML) blast crisis cell line representing a pluripotent precursor cell. At the molecular level, K562 cells express high levels of the aberrant bcr-abl product, p210bcr-abl, believed to be critical to the pathogenesis of CML. The authors demonstrate that exposure of K562 cells to hemin causes a state of partial, reversible erythroid maturation, accompanied by a marked decrease in p210bcr-abl. The change in bcr-abl expression may be mediated at the translational level since steady state amounts and enzymatic activity of the bcr-abl protein are reduced whereas bcr-abl mRNA levels are unaltered. The decrease in p210bcr-abl phosphokinase enzymatic activity can be detected within 2 hours after addition of hemin to the culture media, indicating that changes in expression of this oncogene probably occur before or concurrent with differentiation. No change in bcr-abl protein occurred in a CML cell line (KBM-5) which did not undergo differentiation after exposure to hemin, consistent with a direct relationship between altered p210bcr-abl expression and hemin-induced erythroid differentiation. Importantly, the marked diminution in bcr-abl protein was not associated with a disruption in K562 growth rates, indicating that the proliferative capacity of these cells may be independent of the bcr-abl product. In contrast to hemin, cytosine arabinoside (Ara-C) caused terminal erythroid differentiation of K562 cells, characterized by irreversible hemoglobin accumulation and cytostasis; and no change in bcr-abl protein expression was observed. The distinct effects of Ara-C and hemin could reflect the existence of pleiotropic differentiation pathways. Both Ara-C and hemin-exposed cells showed a decrease in c-myc and c-myb transcripts, suggesting that altered levels of these proto-oncogenes may be associated with erythroid maturation, regardless of the rate of cell division. K562 cells provide a useful model for analyzing the interaction between oncogene expression and CML cell growth and differentiation. PMID: 3044574 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 454: Oncogene Res. 1988 Sep;3(2):187-92. Erythroproliferation in vitro can be induced by abl, fes, src, ras, bas, raf, raf/myc, erb B and cbl oncogenes but not by myc, myb and fos. Klinken SP. Laboratory of Experimental Carcinogenesis and Immunopathology, National Institutes of Health, Bethesda, Maryland 20892. To assess the erythroproliferative effects of a variety of retroviruses in vitro, hemopoietic precursors were incubated with the viruses then plated in methylcellulose. Only replication defective transforming viruses were active in this assay and produced colonies of erythroid cells. The effective transforming viruses were: Friend virus and viruses containing the abl, fes, src, Ha-ras, Ki-ras, bas, raf, raf/myc, erb B and cbl oncogenes. Replication competent viruses and those bearing the myc, myb and fos oncogenes were unable to initiate colony formation. Significant differences were observed in the colonies induced by several of the transforming genes based on (i) colony size, (ii) morphology, (iii) time course of development and (iv) sensitivity to erythropoietin. The oncogene-expressing retroviruses appeared to have the same target cell, which may be less differentiated erythroid precursor than the target cell for Friend virus. PMID: 3226726 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 455: Oncogene Res. 1988 Sep;3(2):147-54. Proto-oncogene expression in chicken leukemic cells induced by avian myeloblastosis virus. Kim WK, Baluda MA. Department of Pathology, School of Medicine, University of California, Los Angeles 90024. Sixteen proto-oncogenes which have generated retroviral oncogenes were tested for their expression in chicken leukemic cells induced by avian myeloblastosis virus (AMV) and five were found to be expressed (c-ets, c-fps, c-mht, c-myc, and c-rel). The size of the c-fps transcript (4.0 kb) was not in good agreement with the size (approximately 3.0 kb) previously reported but was uniform in the leukemic cells from 10 different chickens. The size of the other proto-oncogene transcripts appeared normal. The five expressed proto-oncogenes represent cellular genes involved in hematopoiesis. Interestingly the c-myb gene was not expressed in any of the leukemic cells despite its expression in the immature myeloid cells which are targets for AMV transformation. This could represent down regulation of c-myb by v-myb or a differentiation-related arrest of c-myb expression. The leukemic phenotype induced by v-myb may therefore become expressed at a stage of myeloid differentiation when c-myb expression is repressed. PMID: 3226723 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 456: Mol Endocrinol. 1988 Sep;2(9):816-24. Estrogen induces expression of c-fos and c-myc protooncogenes in rat uterus. Weisz A, Bresciani F. Istituto di Patologia Generale e Oncologia, Prima Facolta di Medicina e Chirurgia, Universita di Napoli, Italy. Estrogen stimulates DNA synthesis and cell proliferation in the luminal and glandular epithelia of rodent uterus. We tested the hypothesis that the mitogenic effect of estrogen occurs via activation of the expression of cellular proto-oncogenes by measuring the rate of transcription of 20 proto-oncogenes (abl, bas, erb-A, erb-B, ets, fms, fos, fps/fes, mos, myb, myc, N-myc, raf, Ha-ras, Ki-ras, N-ras, rel, sis, src, and B-lym) in the uterus of ovariectomized rats before and after injection of estrogen. c-onc transcriptional activity was monitored both by an in vitro transcription assay on isolated nuclei (run-on) and by analysis of mature mRNA. c-fos and c-myc proto-oncogenes were found to respond to estrogen with increased expression: c-fos within 30 min, with a first, sharp peak at 2 h and c-myc within 1.5 h, with a first, broad peak at 4-6 h. DNA synthesis start to increase in the uterus 13 h after estrogen injection and show a first peak at 24 h. In the liver and muscle of the same animals there is neither elevation of c-fos and c-myc expression nor increase of DNA synthesis. The kinetics of the induction by estrogen of c-fos gene expression in the uterus parallels the rate of formation of active nuclear estrogen-receptor complex. Furthermore, the ability of estrogen to induce c-fos mRNA was not abolished by the protein synthesis inhibitor cycloheximide.(ABSTRACT TRUNCATED AT 250 WORDS) PMID: 3173352 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 457: Anticancer Res. 1988 Sep-Oct;8(5A):977-84. Oncogene expression and regulation in normal lymphocytes and lymphocytes from patients with autoimmune diseases. Boumpas DT, Eleftheriades EG, Barez S, Tsokos GC. Kidney Disease Section, National Institutes of Diabetes, Digestive and Kidney Disease, Bethesda, Maryland 20892. The discovery of oncogenes has offered new insights into the physiology of lymphocytes. Proto-oncogenes encode proteins that are associated with the control of lymphocyte activation, proliferation and differentiation. Mononuclear cells from patients and animals with autoimmune disorders express increased quantities of oncogenes such as c-myc, c-myb and c-raf. In this review we discuss some of the cellular and molecular events associated with lymphocyte activation and the role that the oncogenes play in each of these events. The regulation of the expression of oncogenes in these cells is also reviewed. Finally, the role of the increased oncogene expression in the pathogenesis of autoimmune diseases is discussed. Publication Types: Review Review, Tutorial PMID: 3052263 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 458: Mol Cell Biol. 1988 Sep;8(9):3938-42. Expression of the c-myb and c-myc genes is regulated independently in differentiating mouse erythroleukemia cells by common processes of premature transcription arrest and increased mRNA turnover. Watson RJ. Imperial Cancer Research Fund Laboratories, St. Bartholomew's Hospital, Bartholomew Close, London, United Kingdom. The mechanisms that modulate c-myb mRNA levels in mouse erythroleukemia cells induced toward erythroid differentiation were compared with those that act on c-myc. Both genes exhibited regulation at the levels of premature transcription arrest and RNA turnover. However, these common processes allowed temporally distinct control of gene expression. PMID: 2851731 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 459: Cancer Lett. 1988 Aug 15;41(2):147-55. Differential expression of cellular oncogenes during rat liver development. Zhang XK, Wang Z, Lee A, Huang DP, Chiu JF. Department of Biochemistry, College of Medicine, University of Vermont, Burlington 05405. The expression of a number of proto-oncogenes (myc, erb B, Ha-ras, bas, rel, mos, sis, myb, ki-ras, fms, src and fos) was studied in developing rat liver. Northern blot hybridization shows that cellular counterpart of erb B, Ha-ras, and fos oncogenes were in an early stage of liver development, and the expressions of these proto-oncogenes gradually decreased as the liver developed, while c-myc transcript was found only in the rat fetal liver. The transcripts of these oncogenes were found in high level in Morris hepatoma 7777. Bas proto-oncogene was found in high expression at early stages of rat liver development but was not in hepatoma 7777. The expression of other proto-oncogenes studied (src, fm, rel, mos, sis, myb and ki-ras) did not change significantly during liver development and was almost the same in hepatoma and normal adult liver. Southern blot analysis demonstrates that gene amplification and apparent gene rearrangement were not responsible for the change in expression of erb B, Ha-ras, myc and fos proto-oncogenes. Our study gives further evidence that erb B, myc, Ha-ras and fos proto-oncogenes are involved in the control of cell growth and in the process of rat hepatocarcinogenesis. PMID: 2456853 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 460: Cancer Res. 1988 Aug 1;48(15):4307-11. Indistinguishable patterns of protooncogene expression in two distinct but closely related tumors: Ewing's sarcoma and neuroepithelioma. McKeon C, Thiele CJ, Ross RA, Kwan M, Triche TJ, Miser JS, Israel MA. Division of Cancer Treatment, National Cancer Institute, Bethesda, Maryland 20892. Genetic characterization of human tumors promises new insights of biological importance and clinical relevance. We have found that two solid tumors, peripheral neuroepithelioma and Ewing's sarcoma of bone, which share a common cytogenetic rearrangement, are characterized by an indistinguishable and highly reproducible pattern of protooncogene expression. c-myc, N-myc, c-myb, and c-mil/raf-1 are all expressed at similar levels in these tumors. c-fes and c-sis expression was not detected in any specimens of either tumor. In contrast, the protooncogene c-ets-1, located near the breakpoint of the chromosomal translocation in these tumors, is variable in its expression. We also detected high levels of choline acetyltransferase in these tumors, which suggests a common neural origin. Since it is likely that the clinical behavior and therapeutic responsiveness of tumors relate closely to their biological and genetic features, the pattern of protooncogene expression of individual tumors may provide a novel basis for their characterization. PMID: 3390826 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 461: Mech Ageing Dev. 1988 Aug;44(2):153-68. Age-related changes of proliferative response, kinetics of expression of protooncogenes after the mitogenic stimulation and methylation level of the protooncogene in purified human lymphocyte subsets. Deguchi Y, Negoro S, Hara H, Nishio S, Kishimoto S. Third Department of Internal Medicine, Osaka University Hospital, Japan. Proliferative responses of highly purified T and B cells from aged persons to the combined stimulation with ionomycin and PMA were more significantly reduced than that from young ones although the degree of the age-related reduction was more significant in T cells than in B cells. In B cells, the levels and kinetics of c-myc gene expression after the stimulation were comparable between aged and young groups. In T cells, the maximum level of c-myc gene expression after the stimulation was comparable between the two age groups but the rate of reduction of c-myc mRNA was significantly retarded in the aged. The results of nuclear run on transcription assay showed the reduction of the rate of c-myc mRNA degradation seemed to be the cause. The levels and kinetics of c-myb gene expression in either T or B cells were comparable between the two age groups. We further examined the level of methylation of Xho I site of c-myc gene. The level of the methylation was significantly lower in the aged T cells and more significant in aged CD 8 positive T cells although that in aged B cells was comparable to that in young ones. The relation between a reduced proliferation, a retarded rate of c-myc mRNA degradation and reduction of methylation level of c-myc gene was discussed. PMID: 3262794 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 462: 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] --------------------------------------------------------------- 463: J Clin Lab Immunol. 1988 Aug;26(4):163-8. Proto-oncogene expression and nuclear factor specifically bound to c-myc gene in peripheral blood mononuclear cells from progressive systemic sclerosis patients as the indicator of clinical activity. Deguchi Y, Negoro S, Kishimoto S. Third Department of Internal Medicine, Osaka University School of Medicine, Japan. In the present study, we examined the expression of various protooncogenes and the specific binding of nuclear factor to c-myc gene in peripheral blood mononuclear cells (PBMC) from progressive systemic sclerosis (PSS) patients. We demonstrated first amplified expression of c-myc and c-myb gene and the existence of a nuclear protein specifically bound to 5'-non-coding fragment of c-myc gene. We then found a positive correlation between the degree of expression and/or affinity for the c-myc gene fragment of the nuclear protein and clinical disease activity. The amount of the factor was significantly reduced along with or prior to the amelioration of clinical symptoms and laboratory abnormalities with treatment. The significance of c-myc and c-myb proto-oncogene expression and nuclear factor specifically bound to c-myc gene is discussed. PMID: 3058983 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 464: Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi. 1988 Aug;21(3):141-50. Expression of oncogenes in human hepatoma cell lines. Ting LP, Jeng KS, Chou CK, Su TS, Hu CP, Wong FH, Chang HK, Chang CM. Graduate Institute of Microbiology and Immunology, National Yang-Ming Medical College, Taipei, Taiwan, ROC. The expression of 20 known cellular proto-oncogenes in human well-differentiated hepatoma cell line Hep3B and poorly-differentiated hepatoma cell line HA22T/VGH was studied by Northern blot hybridization. Among the cellular proto-oncogenes examined, both cell lines express protein kinase genes including fps, mos and raf; PDGF B chain sis gene; GTP/GDP binding protein gene Ha-ras and nuclear protein genes including fos and myc. The expression of yes, abl, ros, src, erb-B, erb-A, fms, Ki-ras, myb, rel and bas genes was not detected in both cell lines. PMID: 2854043 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 465: Cancer Res. 1988 Jul 15;48(14):3972-6. Erratum in: Cancer Res 1988 Sep 1;48(17):5056. Protooncogene expression in normal, preleukemic, and leukemic murine erythroid cells and its relationship to differentiation and proliferation. Robert-Lezenes J, Meneceur P, Ray D, Moreau-Gachelin F. INSERM U-248, Faculte de Medecine Lariboisiere Saint-Louis, Paris, France. The expression of 18 protooncogenes was examined by Northern blot analysis in preleukemic and leukemic stages of murine erythroleukemias induced by Friend viruses. As controls, erythropoietically stimulated spleens from phenylhydrazine-treated mice were studied. Expression of 10 protooncogenes (c-erb-A, c-erb-B, c-ets, c-sis, c-mos, c-rel, c-src, c-fes, c-fms, N-myc [corrected] was not detectable in Friend erythroleukemias. One protooncogene (c-src) was found expressed in normal erythroid cells but not in erythroleukemias. Four protooncogenes (c-fos, c-abl, N-ras, and c-raf) were expressed at low levels in both steps of erythroleukemia. c-fos and c-abl RNAs were barely detectable in normal erythroid cells. High levels of four protooncogene transcripts (c-H-ras, c-K-ras, c-myc, and c-myb) were detected in preleukemic and leukemic tissues. While c-H-ras RNA was found at similar levels in normal and leukemic erythroid cells, c-myc, c-myb, and c-K-ras were not expressed in normal erythroid cells. To determine whether the elevated levels of c-myc, c-myb, and c-K-ras RNAs in erythroleukemic cells are related to the proliferative state or the undifferentiated state of the cells, the effect of dimethyl sulfoxide-induced differentiation on oncogene expression in two erythroleukemia cell lines was examined. Terminal differentiation was associated with lack of c-myb expression while c-myc and c-K-ras expression was essentially unaffected. These results suggest that the high levels of c-myb transcripts in erythroleukemias may reflect the undifferentiated state of the leukemic cells. In contrast, the elevated expression of c-myc and c-K-ras at both stages of the Friend diseases is probably not related to the stage of differentiation but rather to the uncontrolled proliferation of the cells. Finally among 18 protooncogenes surveyed, only the accumulation of c-myc and c-K-ras RNAs appears to be associated with the Friend erythroleukemic process before the late leukemic phase develops. PMID: 3164254 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 466: J Immunol. 1988 Jul 15;141(2):681-9. A chronic inflammatory response. Its role in supporting the development of c-myb and c-myc related promonocytic and monocytic tumors in BALB/c mice. Wolff L, Mushinski JF, Shen-Ong GL, Morse HC 3rd. Laboratory of Genetics, National Cancer Institute, Bethesda, MD 20892. This study demonstrates that an inflammatory response caused by the injection of pristane into the peritoneal cavity of mice provides a useful system for rapid induction of myeloid tumors by retroviruses. Two such tumors, which developed in the peritoneal cavity with average latencies of 68 to 71 d and incidences of greater than 50%, are 1) the McML, mature monocyte-macrophage tumors induced by retroviral constructs containing exons 2 and 3 of c-myc cDNA, and 2) the MML, promonocytic tumors induced by Moloney murine leukemia virus infection and its integration into the c-myb locus. Development of both neoplasms is clearly dependent on the intense i.p. inflammatory response, inasmuch as mice given the viruses and not pristane fail to develop these tumors. Although both types of tumors appear in the peritoneal cavity, the MML tumors that arise by i.v. injection of Moloney murine leukemia virus may actually originate via infection, and perhaps transformation, of precursor hemopoietic cells outside the peritoneal cavity, followed by migration of the cells to the peritoneal cavity. This is suggested by the fact that i.v.v but not i.p. injection of virus is an efficient method of producing these particular myeloid tumors. Although both McML and MML tumors require the inflammatory environment for their development, treatment of mice with a nonsteroid anti-inflammatory drug, indomethacin, has no effect on McML monocyte/macrophage tumors but completely prevents the development of the MML promonocyte tumors. PMID: 2838552 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 467: Biull Eksp Biol Med. 1988 Jul;106(7):86-8. [Expression of oncogenes in transplantable tumors and rodent cell lines] [Article in Russian] Kudriavets IuI, Kiseleva NP, Asanova AA, Pinchuk VG. The expression of 8 oncogenes in transplanted rodent tumours and cell lines was tested. In 6 cases the synthesis of myc-, fos-, ras-oncogene RNA was observed. The transcription of these oncogenes was observed nonspecifically in tumours of different histological types. No difference in the set of the oncogenes expressed and the size of their transcripts was noticed between transplanted tumours and the cell lines obtained from them. The expression of myb-, sis-, Blym-, erb-B- and abl-was not observed in tested cells. PMID: 3401585 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 468: J Virol. 1988 Jul;62(7):2464-73. Comparison of expression in hemopoietic cells by retroviral vectors carrying two genes. Bowtell DD, Cory S, Johnson GR, Gonda TJ. Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia. In order to identify factors that influence expression by retroviral vectors in hemopoietic cells, we have compared viral RNA levels in cells infected with several different recombinant viruses. All of the vectors tested carry the neomycin resistance gene and provide for the insertion of a second gene which, in these studies, comprised sequences from the myc or myb oncogenes or the gene encoding granulocyte-macrophage colony-stimulating factor. The vectors utilize two different strategies for the coexpression of the two genes: alternate splicing and the use of a separate internal promoter. We found that expression in hemopoietic cells could be increased by substituting sequences from the myeloproliferative sarcoma virus long terminal repeat for those of the Moloney murine leukemia virus long terminal repeat. However, none of the vectors examined was able to express a second gene at levels equivalent to those achieved by the parental vectors carrying only the neomycin resistance gene. The reasons for this varied with the different vectors and included inefficient splicing and/or a reduction in the level of unspliced transcripts upon insertion of a second gene. Although the basis of the latter phenomenon is not clear, it is probably related to the position--near the 5' long terminal repeat--at which the second gene was inserted, since insertion of the same genes near the 3' end of another vector had no effect on viral RNA levels. In an attempt to circumvent some of these problems, we constructed a vector that employs an internal beta-actin promoter. Although this vector could express granulocyte-macrophage colony-stimulating factor sequences in a responsive hemopoietic cell line, the level of granulocyte-macrophage colony-stimulating factor produced was disappointingly low. The results from these studies suggest approaches to the design of improved vectors for effective expression of genes in hemopoietic cells. PMID: 3373574 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 469: 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] --------------------------------------------------------------- 470: Mol Cell Biol. 1988 Jun;8(6):2504-12. c-myc and c-myb protein degradation: effect of metabolic inhibitors and heat shock. Luscher B, Eisenman RN. Viral Oncology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104. The proteins encoded by both viral and cellular forms of the c-myc oncogene have been previously demonstrated to have exceptionally short in vivo half-lives. In this paper we report a comparative study on the parameters affecting turnover of nuclear oncoproteins c-myc, c-myb, and the rapidly metabolized cytoplasmic enzyme ornithine decarboxylase. The degradation of all three proteins required metabolic energy, did not result in production of cleavage intermediates, and did not involve lysosomes or ubiquitin. A five- to eightfold increase in the half-life of c-myc proteins, and a twofold increase in the half-life of c-myb proteins was detected after heat-shock treatment at 46 degrees C. In contrast, heat shock had no effect on the turnover of ornithine decarboxylase. Heat shock also had the effect of increasing the rate of c-myc protein synthesis twofold, whereas c-myb protein synthesis was decreased nearly fourfold. The increased stability and synthesis of c-myc proteins led to an overall increase in the total level of c-myc proteins in response to heat-shock treatment. Furthermore, treatments which reduced c-myc and c-myb protein turnover, such as heat shock and exposure to inhibitors of metabolic energy production, resulted in reduced detergent solubility of both proteins. The recovery from heat shock, as measured by increased turnover and solubility, was energy dependent and considerably more rapid in thermotolerant cells. PMID: 3043180 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 471: Circ Res. 1988 Jun;62(6):1075-9. Expression of cellular oncogenes in the myocardium during the developmental stage and pressure-overloaded hypertrophy of the rat heart. Komuro I, Kurabayashi M, Takaku F, Yazaki Y. Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan. Proto-oncogenes have been revealed to participate in normal cell proliferation as well as in cell transformation. Since cardiac myocytes are terminally differentiated, they cannot divide except in the fetal period. To determine the role of cellular oncogenes in the growth of the heart, the expression pattern of eight cellular oncogenes during the developmental stage and pressure-overloaded hypertrophy of the rat hearts were examined in vivo. Northern blot analysis was performed with eight oncogene probes (myc, fos, Ha-ras, src, erbA, erbB, sis, myb). Pressure overload increased the levels of cellular (c-) fos, c-myc, and c-Ha-ras. An increase of c-fos and c-myc was detected at 30 minutes and 2 hours, respectively; the levels peaked at 8 hours, and they returned to baseline by 48 hours after aortic constriction. However, the level of c-Ha-ras showed a gradual increase. During the course of development, the expression of c-myc was detectable only in the embryonic stage, whereas the expression of c-fos was not detected in the fetal period, was increased after birth, and peaked in 200-day-old adults. The expression of c-Ha-ras was almost the same throughout the development. Cellular oncogenes were expressed in the heart in response to pressure overload and in a stage-specific manner. These results suggest that cellular oncogenes may participate in the normal developmental process and hypertrophy of hearts and that the cellular hypertrophy induced by pressure overload may share a similar mechanistic pathway with cell proliferation. PMID: 2454761 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 472: Br J Cancer. 1988 May;57(5):464-8. Structure and expression of oncogenes in surgical specimens of human breast carcinomas. Biunno I, Pozzi MR, Pierotti MA, Pilotti S, Cattoretti G, Della Porta G. Division of Experimental Oncology A, Istituto Nazionale Tumori, Milan, Italy. We have performed an analysis of ras, c-myc, c-myb, c-erbB1 and c-erbB2 oncogenes in 100 surgical samples of human breast carcinomas. No point mutations have been detected at the 12th codon of c-Ha-ras and c-Ki-ras in 40 and 65 breast cancer DNAs, respectively. One out of 65 samples showed a 50-fold amplification of c-Ha-ras that, however, was not overexpressed. Alterations in the structure of c-myc, c-myb c-erbB1 and c-erbB2 oncogenes were sporadically observed. In 20 tumour samples, the study of expression of a series of oncogenes revealed that c-Ha-ras was the predominantly transcribed gene among the ras gene family whereas c-fos appeared the most constantly and significantly expressed nuclear oncogene. PMID: 3293644 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 473: Carcinogenesis. 1988 May;9(5):817-21. Cellular-oncogene expression in Friend erythroleukemia cells: relationship to differentiation, commitment and TPA effects. Giroldi L, Hollstein M, Yamasaki H. International Agency for Research on Cancer, Lyon, France. Induced differentiation of Friend erythroleukemia cells can be continuously and reversibly inhibited by phorbol ester tumor promoters, e.g. 12-O-tetradecanoylphorbol-13-acetate (TPA), for many years, allowing us to study the mechanisms of differentiation and its inhibition by TPA. We previously identified two steps in the differentiation process, which can be inhibited by TPA, before and after commitment to differentiation. Using permanently committed cells and TPA-resistant variants we examined the role of cellular oncogenes in Friend cell differentiation control, and their possible modulation by tumor-promoting phorbol esters. We report here characteristic changes in myc, myb and fos mRNA levels upon induction of differentiation by hexamethylene bisacetamide treatment, and present evidence that c-myb mRNA decline is one feature of Friend cell commitment to differentiation. In addition, using our TPA-sensitive and resistant cell lines, we observed that the hexamethylene bis-acetamide induced pattern of oncogene expression is unperturbed by TPA, regardless of whether the cells are differentiating or not. PMID: 3163274 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 474: J Biol Chem. 1988 Apr 5;263(10):4828-31. Mitogenic activation of normal T cells leads to increased initiation of transcription in the c-myc locus. Kelly K, Siebenlist U. Immunology Branch, National Cancer Institute, Bethesda, Maryland 20892. Early following mitogenic activation, normal human T cells express elevated levels of steady-state mRNAs encoding the nuclear-localized protooncogenes, c-fos, c-myc, and c-myb. Although the mechanisms responsible for increases in these specific mRNAs are not known, recent evidence suggests that up-regulation of c-myc could result from the release of a nascent chain elongation block. Run-on transcription analyses of c-myc show here that increased initiation and not modulation of elongation efficiency is largely responsible for elevated c-myc mRNA levels in activated T cells. Transcriptional stimulation of c-myc commences from a chromatin state that appears poised for activation. As determined by DNase I hypersensitive site analyses, the chromatin structure of c-myc in resting T cells resembles that of other cell types expressing high levels of c-myc, and furthermore, no changes in hypersensitive sites can be correlated with mitogenic stimulation of c-myc transcription. Because mitogen-induced up-regulation and terminal differentiation-associated down-regulation of c-myc are mechanistically different, it appears that c-myc is subject to a variety of distinct transcriptional controls. In addition to c-myc, c-fos and c-myb are shown to be induced via a transcriptional mechanism in T cells. PMID: 3127392 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 475: J Virol. 1988 Apr;62(4):1423-32. Rapid induction of B-cell lymphomas: insertional activation of c-myb by avian leukosis virus. Kanter MR, Smith RE, Hayward WS. Sloan-Kettering Institute for Cancer Research, New York, New York 10021. EU-8 is a recombinant avian leukosis virus (ALV) constructed in vitro, which carries long terminal repeats and gag and pol genes from ring-necked pheasant virus and the env gene from UR2AV. Unlike either parent virus, when injected into 10-day-old chicken embryos, EU-8 induces a high incidence of clonally arising B-cell lymphomas within an unusually short latent period, often causing death within 5 to 7 weeks after infection. These tumors differ from the classic lymphoid leukosis induced by ALV in several respects, both biologically and at the molecular level. Most notably, in all of the EU-8-induced tumors examined, the provirus was integrated in the c-myb locus, and in no tumors were c-myc integrations found. Most of the proviral integrations were downstream of the initiation codon of c-myb and thus presumably resulted in some truncation of the c-myb gene product, although not to the same extent as has been found in other cases of c-myb activation. In addition, several of the proviruses were integrated well upstream of the c-myb coding region. This is the first report of ALV interaction with the c-myb proto-oncogene and the first report of c-myb activation resulting in tumors of lymphoid rather than myeloid origin, suggesting that the target cell specificity of transformation by the myb gene is not as restricted as previously believed. PMID: 2831403 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 476: Eur J Biochem. 1988 Mar 1;172(2):333-40. Differential mRNA stability to reticulocyte ribonucleases correlates with 3' non-coding (U)nA sequences. Wreschner DH, Rechavi G. Department of Microbiology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel. The stabilities of different mRNA species were analyzed in a reticulocyte lysate system under protein-synthesizing conditions. In all cases examined the relative mRNA degradation by reticulocyte ribonucleases as well as by the interferon-modulated (2'-5') (A)n-dependent endonuclease correlated with the extent of (U)nA sequences within the 3' non-coding region. The experimental data presented indicate that according to their stabilities at least three major mRNA groups may be identified: (a) (U)nA-poor mRNAs (e.g. globin) are essentially stable and are only slightly degraded by the (2'-5')(A)n-dependent endonuclease; (b) mRNA species with intermediate (U)nA levels (e.g. Ig alpha and Ig mu heavy-chain mRNAs) are partially degraded by general ribonuclease activity and further degraded by the (2'-5')(A)n-dependent endonuclease and (c) (U)nA-rich mRNA species (such as c-myc and non-skeletal actin mRNAs) are inherently unstable and are extremely sensitive to degradation by general ribonuclease activity. A survey of mRNA nucleotide sequences demonstrated that without exception (U)nA-rich stretches appeared more frequently within the 3' non-coding region than in the coding or 5' non-coding regions. A comparison of 3' non-coding region sequences from 92 different mRNAs revealed that transiently expressed mRNAs, such as the interleukins, nerve growth factor, epidermal growth factor receptor, c-myc, c-fos, c-myb and several other oncogenes as well as interferons alpha, beta and gamma were exceptionally (U)nA-rich. It is postulated that differential mRNA stability may be partly determined by the primary nucleotide sequence and in particular by (U)nA sequences within the 3' non-coding region. This may represent a novel post-transcriptional strategy employed by the cell to selectively retain or destroy discrete mRNA species. PMID: 3350000 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 477: Biull Eksp Biol Med. 1988 Mar;105(3):326-9. [Cellular oncogene expression in human tumors transplantable to athymic mice] [Article in Russian] Spitkovskii DD, Revazova ES. Expression of 3 cellular oncogenes among 7 ones under investigation is identified in the majority of 20 strains of human tumors, passaged in nude mice without significant specificity as far as the type of the tumor is concerned. The levels of the expression of these 3 oncogenes (c-myc, c-fos, c-ras) were higher than the ones in primary human tumors except for the human melanoma Mel-2 strain, where the expression of c-myb oncogene was identified. All the rest oncogenes (c-mos, B-lym, c-sis, c-myb) showed no expression in human tumors of the examined strains. PMID: 3349173 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 478: Oncogene. 1988 Mar;2(3):267-72. A transcriptional arrest mechanism involved in controlling constitutive levels of mouse c-myb mRNA. Watson RJ. Imperial Cancer Research Fund Laboratories, St Bartholomew's Hospital, London, UK. The control of c-myb mRNA abundance was examined in three representative cell lines, (the erythroleukaemia F4-12B2, the myeloma MOPC-31C and the fibroblast NIH3T3), which display abundant, low and undetectable levels of this transcript, respectively. We observed a small difference in half-life between F4-12B2 and MOPC-31C c-myb mRNA (175 min and 105 min, respectively) insufficient to account for the approximately 20-fold lower levels of this transcript in myelomas. Using the run-on transcription assay we found that c-myb transcripts were initiated at similar rates in all three cell types and were elongated at this relatively high rate to a site approximately 2 kilobases into the first intron. NIH3T3 c-myb transcripts did not proceed detectably beyond this pause/attenuation site, while in F4-12B2 cells transcription of regions 3' of this site occurred at a rate approximately 12-fold greater than in MOPC-31C. We have concluded that this transcriptional arrest mechanism, together with small differences in RNA turnover, were sufficient to account for the spectrum of c-myb mRNA abundance observed. Despite evidence of transcript initiation, we were unable to detect c-myb mRNA in fibroblasts, even under conditions (e.g. serum stimulation) which induced high c-myc mRNA levels. However, a novel 3.0 kilobase transcript with homology to c-myb was detected in cycloheximide-treated NIH3T3 cells. PMID: 3281094 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 479: J Virol. 1988 Mar;62(3):839-46. Comparative molecular genetic analysis of lymphomas from six inbred mouse strains. Mucenski ML, Bedigian HG, Shull MM, Copeland NG, Jenkins NA. National Cancer Institute-Frederick Cancer Research Facility, Bionetics Research, Inc., Maryland 21701. Previous studies of 21 highly lymphomatous AKXD recombinant inbred mouse strains demonstrated correlations between lymphoma type, the somatic proviral DNA content of the lymphoma, and the frequency of virally induced rearrangements in eight common sites of viral integration (Myc, Pim-i, Pvt-1, Mlvi-1, Mlvi-2, Fis-1, Myb, and Evi-1). In this study we analyzed lymphomas from six inbred mouse strains, AKR/J, C58/J, HRS/J (hr/hr and hr/+), SJL/J, SEA/GnJ, and CWD/LeAgl, to determine whether these correlations are also evident in these strains. Mice of the AKR/J, C58/J, and HRS/J strains died exclusively of T-cell lymphomas. In contrast to earlier studies which showed a great disparity in the rate and incidence of lymphomas in HRS/J hr/hr and HRS/J hr/+ mice, we found a high incidence of T-cell lymphomas and the same mean age of onset of disease in both strains. SJL/J mice died primarily of pre-B-cell lymphomas, whereas CWD/LeAgl and SEA/GnJ mice died primarily of B-cell lymphomas. Somatically acquired mink cell focus-forming proviruses were detected only in T-cell lymphomas, whereas ecotropic proviruses were found in lymphomas from all hematopoietic cell lineages. No rearrangements were detected in the Fis-1, Mlvi-2, and Myb loci, whereas rearrangements were detected in the Mlvi-1, Myc, Pim-1, Pvt-1, and Evi-1 loci. Most rearrangements were found in T-cell lymphomas, and many were virally induced. These results are similar to those we obtained previously for lymphomas of 21 highly lymphomatous AKXD recombinant inbred mouse strains. PMID: 2828679 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 480: Int J Cancer. 1988 Feb 15;41(2):287-96. Biological characterization and oncogene expression in human colorectal carcinoma cell lines. Trainer DL, Kline T, McCabe FL, Faucette LF, Feild J, Chaikin M, Anzano M, Rieman D, Hoffstein S, Li DJ, et al. Department of Cell Biology, Smith Kline and French Laboratories, Philadelphia, PA 19101. To establish well-characterized cellular reagents for the study of colon carcinoma, we have examined 19 human colorectal carcinoma cell lines with regard to morphology, ultrastructure, expression of tumor-associated antigens, proliferative capacity in vitro, anchorage-independent growth, oncogene expression, tumorigenicity and malignant potential. Cell lines examined were cultured under identical conditions, and in vitro and in vivo analyses were performed in parallel on replicate cultures. Three classes of colorectal cell lines were defined according to their tumorigenicity in nude mice. Class-1 lines formed rapidly progressing tumors in nearly all mice at an inoculum of 10(6) cells. Cell lines belonging to class-2 were less tumorigenic, producing tumors later and at a slower growth rate. Class-3 lines were non-tumorigenic under all experimental conditions tested. By Northern analysis, the oncogenes c-myc, H-ras, K-ras, N-ras, myb, fos and p53 were expressed in nearly all cell lines examined. In contrast, transcripts for abl, src and ros were not detected. The best in vitro predictor of tumorigenicity was colony formation in soft agar. There was no detectable correlation between tumorigenicity and metastatic potential, doubling time in vitro, production of tumor-associated markers, xenograft histology or expression of specific oncogenes. PMID: 3338874 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 481: Oncogene. 1988 Feb;2(2):167-74. Myeloperoxidase and oncogene expression in GM-CSF induced bone marrow differentiation. Jaffe BD, Sabath DE, Johnson GD, Moscinski LC, Johnson KR, Rovera G, Nauseef WM, Prystowsky MB. Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia. DNA synthesis, morphology, specific RNA accumulation and rates of specific protein synthesis in GM-CSF stimulated bone marrow progenitor cells were studied. DNA synthesis increased markedly for 64 hours and then gradually decreased to 5% maximal activity by 160 hours. Morphologic examination 40 to 64 hours after stimulation revealed an increasing proportion of immature myeloid cells. After this proliferative peak, cells differentiated into segmented neutrophils and monocytes/macrophages; only mature forms were present by 160 hours. Accumulation of mRNA for c-myb and c-myc was maximal at 40 hours just prior to maximal [3H]thymidine incorporation, while maximal accumulation of histone type 3 (H3) was coincident with maximal [3H]thymidine incorporation at 64 hours. As proliferation decreased and differentiation proceeded, levels of mRNA for c-myb and H3 decreased markedly, while levels of RNA for c-myc decreased gradually and remained elevated above day 0 levels. Levels of c-fos mRNA fluctuated slightly during the first 64 hours of culture and increased 13-fold by 160 hours when mature cells were present. Similarly, beta-2 microglobulin mRNA increased steadily to maximal levels at 112 to 160 hours which were 15-fold higher than day 0 levels. Myeloperoxidase (MPO) mRNA was present in maximal amounts at 40 to 64 hours after stimulation with GM-CSF as the number of immature myeloid cells peaked. Immunoprecipitation of MPO from pulse-labeled cell lysates demonstrated a 7-fold rise in synthetic rate of MPO of 64 hours and a 28-fold decline by 160 hours when only 5% immature myeloid cells were present. Thus, MPO protein synthesis closely follows MPO mRNA accumulation. Immunoprecipitation of lactoferrin, a marker of myeloid secondary granules, demonstrated a gradual 5-fold increase in synthetic rate as the cells matured. Taken together, these data show that maximal expression of the early myeloid differentiation enzyme myeloperoxidase in GM-CSF stimulated normal bone marrow cells occurs during peak proliferation of immature myeloid cells. PMID: 2835725 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 482: Mol Cell Biol. 1988 Feb;8(2):884-92. Constitutive expression of a c-myb cDNA blocks Friend murine erythroleukemia cell differentiation. Clarke MF, Kukowska-Latallo JF, Westin E, Smith M, Prochownik EV. Department of Internal Medicine, University of Michigan, School of Medicine, Ann Arbor 48109. A full-length human c-myb cDNA clone has been isolated from a CCRF-CEM leukemia cell cDNA library. The plasmid vector contains simian virus 40-derived promotor, splice, and polyadenylation sequences as well as a transcription unit for a dihydrofolate reductase cDNA. We have introduced this construct into Friend erythroleukemia (F-MEL) cells and have isolated a number of clones which contain intact and transcriptionally active human c-myb sequences. F-MEL clones expressing the highest levels of the human c-myb mRNA differentiate poorly in response to dimethyl sulfoxide. Two clones which initially expressed low levels of human c-myb transcripts and which differentiated normally were subsequently inhibited in their ability to differentiate when grown in successively higher concentrations of methotrexate, due to amplification and enhanced expression of plasmid sequences. The inhibitory effect on F-MEL differentiation appeared to be independent of the early decline in c-myc transcripts which were normally regulated in all cases examined. Our results indicate that constitutive expression of a nontruncated human c-myb cDNA can exert profound effects on erythroid differentiation and argue for a causal role of c-myb in the F-MEL differentiation process. PMID: 2832742 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 483: Arch Microbiol. 1988 Jan;149(3):175-80. Stimulation of an alpha like DNA polymerase by v-myc related protein of Halobacterium halobium. Ben-Mahrez K, Sougakoff W, Nakayama M, Kohiyama M. Institut Jacques Monod, Universite Paris VII, France. Partial DNA sequencing of a genomic clone of the archaebacterium Halobacterium halobium, which hybridized with an avian v-myc probe, showed especially the presence, in the organism of one of the conserved regions through myb, myc and adenovirus E1a oncogenes. The archaebacterial deduced amino acid sequence displayed significant homology with the v-myc gene product. In accordance with the partial DNA sequencing which assured a sufficient homology to have similar epitopes, a protein having a molecular weight of 70,000 and possessing high antigenicity with a polyclonal antiserum against avian v-myc protein was isolated and purified from H. halobium extracts. The purified v-myc like protein stimulated in vitro DNA synthesis carried out by the alpha like DNA polymerase of H. halobium. PMID: 3284504 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 484: 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] --------------------------------------------------------------- 485: Br J Cancer. 1988 Jan;57(1):48-53. Reactivity of monoclonal antibodies to oncoproteins with normal rat liver, carcinogen-induced tumours, and premalignant liver lesions. Embleton MJ, Butler PC. Cancer Research Campaign Laboratories, University of Nottingham, UK. Monoclonal antibodies to proteins encoded by the ras, myb, myc, erb-B, src and PDGF-2 genes were tested for reactivity with normal rat liver, livers from rats fed with 0.06% 2-acetylaminofluorene (AAF), and premalignant lesions and primary liver tumours from rats given AAF alone or a combined treatment with diethylnitrosamine and AAF. Radioimmunoassays were performed with plasma membrane fractions and total soluble subcellular extracts of the tissues, and immunoperoxidase staining was carried out on frozen tissue sections. All of the antibodies were positive in radioimmunoassays, some more strongly than others, and each antibody bound equally to extracts of different kinds of tissue. Immunohistology revealed significant staining of normal liver by 5 of the 6 antibodies, and only minor qualitative differences of the staining pattern in some tumours and hyperplastic nodules. It was concluded that these antibodies were not able to discriminate sufficiently well between normal, premalignant and malignant rat liver to be of value in identifying the precursor cells of malignant tumours. PMID: 3279994 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 486: Oncogene Res. 1988;3(1):33-7. Expression of oncogenes in normal and transformed murine B lymphocytes. DeCino P, Lernhardt W, Herbst H, Raschke WC. La Jolla Cancer Research Foundation, CA 92037. Proliferating, lipopolysaccharide-stimulated murine B lymphoblasts and a number of transformed murine B cell lines representing various differentiation stages of B cell lineage all express the myc, H-ras and K-ras oncogenes. N-ras transcripts are also present in the B cell blasts and some of the cell lines. In addition, abl, fms, fos, myb, src, and yes are transcribed in some or all of the cell lines but not in the normal B cell blasts. Only myb is expressed in a differentiation stage-specific manner; transcripts are present in the pre-B cell lines and a few of the B lymphomas but not in any plasmacytomas tested. The erbB, fes, mos, and sis probes do not hybridize with mRNA from any of the 15 cell lines or normal B cells. ErbA is not detectable in transformed cells but is expressed in the normal B cell blasts at a low level suggesting its possible involvement in normal growth regulation. PMID: 3264606 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 487: Mol Carcinog. 1988;1(1):41-9. Timing of proto-oncogene replication: a possible determinant of early S phase sensitivity of C3H 10T1/2 cells to transformation by chemical carcinogens. Doggett NA, Cordeiro-Stone M, Chae CB, Kaufman DG. Department of Pathology, Lineberger Cancer Research Center, Chapel Hill, North Carolina 27599. The temporal order of replication of several genes was studied in 10T1/2 cells synchronized by release from confluence-induced arrest of proliferation followed by treatment with 2 micrograms/mL aphidicolin for 24 h. DNA subjected to bromodeoxyuridine substitution for 1- or 2-h intervals spanning the S phase was separated from the remaining DNA in cesium chloride gradients, filtered onto nitrocellulose in a slot-blot apparatus, and hybridized with various 32P-labeled probes. Ha-ras was among the first genes replicated at the onset of the S phase. The myc proto-oncogene replicated later but within the first hour of the S phase. The replication of Ki-ras, raf, and mos was detected between hour 1 and 2 of the S phase. The dihydrofolate reductase gene replicated early (0-2 h) and the myb proto-oncogene replicated in mid-S phase (2-4 h). An immunoglobulin VH sequence and the beta-globin gene replicated late in 10T1/2 cells, 4-6 h after removal of aphidicolin. Replicating DNA is preferentially adducted by chemical carcinogens, and replication of damaged proto-oncogenes before they are repaired may activate their transforming potential. Therefore, the observed replication of proto-oncogenes during the early S phase may underlie the enhanced sensitivity of 10T1/2 cells to chemically induced transformation at this point in the cell cycle. PMID: 3255390 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 488: Prostate. 1988;13(4):263-72. Oncogene expression in prostate cancer: Dunning R3327 rat dorsal prostatic adenocarcinoma system. Cooke DB, Quarmby VE, Mickey DD, Isaacs JT, French FS. Laboratories for Reproductive Biology, University of North Carolina, Chapel Hill 27599. Steady-state levels of myc, fos, p53, sis, and neu mRNAs were measured in eight variants derived from the Dunning R3327 rat prostate adenocarcinoma and compared to levels in normal dorsal prostate. Expression of the myb and erbB oncogenes in the Dunning tumors was below the limits of detection. Myc, p53, and sis mRNA levels in all tumors were at or above control levels. Fos mRNA levels were below control levels in four of five anaplastic tumors and were above control levels in the remaining tumors. A comparison of mRNA levels along the two Dunning lineages revealed that increased expression of these oncogenes did not correlate with tumor progression. PMID: 3217275 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 489: Soc Gen Physiol Ser. 1988;43:371-80. Biochemical and molecular events controlled by lymphokine growth factors. Farrar WL, Harel-Bellan A, Ferris DK. Laboratory of Molecular Immunoregulation, National Cancer Institute, Frederick, Maryland. The polypeptide hormones that govern the proliferation and differentiation of the mature immune system and hematopoiesis are collectively referred to as lymphokines. We have examined a number of biochemical and molecular events stimulated by several unique lymphokines that exhibit proliferative activity on lymphoid and myeloid cell lines. IL-2 and several members of the colony-stimulating factors (multi-CSF, G-CSF, and GM-CSF) stimulate a similar pattern of cellular phosphorylation, including the prominent phosphorylation of a 68-kD substrate present in numerous distinct lineage cell lines. The 68-kD substrate is phosphorylated by protein kinase C on threonine residues and is primarily cytosolic. Another kinase system activated by either physiological ligand or synthetic diacylglycerol phosphorylated the 40S ribosomal S6 protein in a dose-dependent manner. The increased phosphorylation of S6 protein was associated with enhanced chain elongation in vitro. The kinase responsible for the in situ phosphorylation, however, was not protein kinase C but another physicochemically distinct Mg++-dependent enzyme (termed S6 kinase). These studies suggested that although protein kinase C was activated by diacylglycerol, another kinase, S6 kinase, was the effector enzyme involved in the phosphorylation of the 40S protein. IL-2 and all other lymphokines tested stimulated the transcription of the nuclear protooncogenes c-fos, c-myc, and c-myb, as well as a member of the heat shock family of proteins, HSP 70. Phorbol esters also stimulated similar gene expression; however, cAMP analogue inhibited phorbol ester- or ligand-induced c-myc expression. cAMP agonists are antiproliferative to all the growth factors tested. Publication Types: Review Review, Tutorial PMID: 3077555 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 490: Hematol Pathol. 1988;2(4):229-37. Aberrant expression of the K-ras proto-oncogene in B-cell malignancies. Lee J, Talpaz M, Walters R, Gutterman JU, Blick M. Department of Hematology, University of Texas M.D. Anderson Hospital and Tumor Institute, Houston. The proto-oncogenes have the capacity for conversion to an oncogene that is capable of inducing or maintaining the transformed state when they are overly expressed or altered by mutation or rearrangement. To study the possible involvement of these genes in the neoplastic transformation of B-cell malignancies, we have analyzed their expression in 18 fresh samples obtained from the peripheral blood of patients with a variety of B-cell malignancies. A high-molecular weight c-k-ras transcript (5.2 kb) was detected in all samples including normal lymphocytes. In contrast, a low-molecular weight c-k-ras transcript (1.2 kb) was not detected in our control normal lymphocytes, but was found in 9 fresh samples. The 1.2 kb c-k-ras transcript was expressed 2-3-fold higher than the 5.2 kb c-k-ras transcript. C-h-ras (2.9 kb, 1.4 kb) was expressed at a low level in 4 and 13 samples, but not in normal lymphocytes. C-myc (2.3 kb) and c-raf (3.8 kb) were expressed in all samples including normal lymphocytes without significant variation in the level of expression. C-fos (2.2 kb) was expressed in 15 samples and normal lymphocytes with a wide range in the level of expression. C-myb (3.7 kb) and c-fes (2.7 kb) were expressed at a low level in 6 and 10 samples, respectively, including normal lymphocytes. C-sis (4.0 kb) was not detected in any sample including normal lymphocytes. PMID: 3075608 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 491: Oncogene Res. 1988;3(1):39-49. Influence of interferon-alpha on the expression of cellular oncogenes in primary chronic lymphocytic leukemia cells. Einhorn S, Showe L, Ostlund L, Juliusson G, Robert KH, Gahrton G, Croce C. Wistar Institute of Anatomy and Biology, Philadelphia, Pennsylvania 19104. The influence of interferon-alpha 2 (IFN-alpha 2) on the mRNA levels of cellular proto-oncogenes was studied in malignant cells from patients with chronic lymphocytic leukemia (CLL). These cells can be induced to blast transform, differentiate and, in some cases, proliferate upon exposure to IFN. Treatment with IFN-alpha enhanced the levels of c-myc mRNA in malignant cells from the patients, whereas the levels of c-myb mRNA decreased, as measured by slot blot hybridizations. In cells from some patients, an enhanced expression of c-fos and k-ras was observed following exposure to IFN-alpha. No major effect on the expression of c-raf or of enolase was observed in any of the patients following exposure to IFN-alpha, whereas the levels of beta 2-microglobulin mRNA increased. In contrast to the observed effects on oncogene expression in CLL cells, IFN had no major effect on the expression of any of the tested oncogenes in lymphocytes from healthy donors or in B-cells from three neoplastic cell lines (380, FL18, RS). We conclude that IFN-alpha can enhance or repress the expression of several oncogenes in nondividing primary malignant cells from patients with leukemia. We also show that the response of malignant cells from patients to IFN-alpha is different than that seen with neoplastic cell lines which represent a similar stage of B-cell differentiation. PMID: 3060797 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 492: Rev Mal Respir. 1988;5(5):451-61. [Recent progress in the biology of small cell bronchial carcinoma] [Article in French] Thomas F, Arriagada R, Le Chevalier T, Poupon MF. Institut Gustave-Roussy, Villejuif. Progress achieved in the understanding of small cell lung cancer (SCLC) include: the establishment and characterization of cell lines with the identification of a variant type with poor prognosis; the use of non-specific biochemical markers such as neuron specific enolase (NSE) and calcitonin; the generation of monoclonal antibodies (MoAbs) directed against SCLC antigens; growth factors including GRP and IGF. GRP or human bombesin produced by the tumor cells favours their own growths; in cytogenetics, with the observation of a characteristic chromosomal abnormality: the deletion of the short arm of chromosome 3 (3p 14-23). The region deleted is currently under study to identify the genes potentially involved in the oncogenesis of SCLC. the activation of several oncogenes: C-myc, N-myc, L-myc, Myb, Raf-1. The amplification of C-myc favors the tumor cell progression and is related to a bad prognosis. This biological approach has confirmed the neuroendocrine origin of these tumor cells (as a result of protein studies of the cytoskeleton and of MoAbs); it has allowed the use of tumor markers in the diagnosis and work-up of SCLC and the consideration of new therapeutic approaches. Current studies concern the deletion of 3p- and the integration of the cytogenetic data, growth factors and oncogenes in a coherent model of the genesis of SCLC. Publication Types: Review Review, Tutorial PMID: 2847257 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 493: Biull Eksp Biol Med. 1988 Jan;105(1):71-4. [Proto-oncogene expression in mouse leukemia induced by the Mazurenko virus] [Article in Russian] Mazurenko NN, Seniuta NB, Gladkova TI, Mazurenko NP. The expression of 8 protooncogenes was examined in different types of murine leukemia induced by Mazurenko virus. C-myc-specific RNA (2, 3 kb and 1.8 kb) was revealed only in tissues of mice with thymomas (T-cell leukemias) but not with generalized leukemias. 1.4 kb Ha-ras RNA transcripts were observed in all RNA species from leukemic mice. The highest expression of the above oncogenes was noted in thymus and lymph nodes, in spleen and liver the expression was lower. Ki-ras, abl, fos, myb, erb and B-lym-specific RNA expression was not observed in any of the tissues tested. The expression of C-myc RNA is believed to be the result of C-myc activation due to provirus integration. PMID: 2827809 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 494: Exp Cell Res. 1987 Dec;173(2):370-8. Oncogene expression in differentiating F9 mouse embryonal carcinoma cells. Lockett TJ, Sleigh MJ. CSIRO Division of Molecular Biology, New South Wales, Australia. Differentiation of F9 mouse embryonal carcinoma cells in culture is accompanied by a decrease in growth rate and loss of tumorigenicity. Cells differentiating in monolayer culture (to parietal endoderm-type cells) or in aggregates (to visceral endoderm-type cells) show qualitatively similar changes in transcript levels from several c-oncogenes. In contrast with other studies with F9 cells, we find an early decrease in c-myb RNA but not in c-myc RNA. This and a later increase in c-src RNA may be associated with decreasing cell growth rate. Before differentiation, induction and maintenance of elevated c-abl RNA levels depend on the presence of retinoic acid in the medium. After differentiation c-abl RNA levels decline only partially when retinoic acid is removed. Increased RNA from c-fos is seen late in differentiation in monolayer cultures only, a change also seen with appearance of similar endoderm cell types in the developing mouse embryo. PMID: 3691668 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 495: Clin Immunol Immunopathol. 1987 Dec;45(3):424-39. Protooncogene expression in peripheral blood mononuclear cells from patients with systemic lupus erythematosus as an indicator of the disease activity. Deguchi Y, Hara H, Negoro S, Kakunaga T, Kishimoto S. Department of Oncogene Research, Osaka University, Japan. In the present study, we examined the various protooncogene expressions in PBMC (peripheral blood mononuclear cell) of systemic lupus erythematosus (SLE) patients to determine if they could be an indicator for the disease activity. We divided SLE patients into "very active," "active," and "remitting" states according to the clinical symptoms in addition to the laboratory data peculiar to SLE. In addition, we determined the amount of circulating immune complex (IC) as one of the representative laboratory indicators for the disease activity. We found a positive correlation with either c-myc or c-myb expression and the amounts of IC and clinical disease activity. The degree of c-myc and c-myb expression was significantly reduced along with or prior to the amelioration of clinical symptoms and improvement as determined by laboratory data under treatment with prednisolone and/or azathioprine administration. The degree of c-myc and c-myb gene expression had no direct relation to the presence of particular clinical sign(s) or autoantibody. The expression of the c-raf gene was found in SLE and other systemic autoallergic patients although it showed no correlation with the disease activity. No significant expression of c-src, c-ras, c-fos, c-fgr, c-fps, c-fes, c-fms, c-yes, c-rel, c-abl, c-mos, c-sis, and c-erb B genes was found in the patients. c-myc and c-myb expression as having pathogenic and clinical significance is discussed. PMID: 3677489 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 496: Cancer. 1987 Dec 1;60(11):2669-74. Erratum in: Cancer 1988 Mar 1;61(5):1064. Abnormalities of protooncogenes in non-small cell lung cancer. Correlations with tumor type and clinical characteristics. Cline MJ, Battifora H. Department of Medicine, University of California at Los Angeles 90024. Twenty-seven primary non-small cell (NSC) lung cancers were analyzed for alterations of protooncogenes by DNA hybridization techniques. Abnormalities were found in 56% of tumors including ten of 16 adenocarcinomas, three of nine squamous cell cancers and two of two larger cell cancers. Five protooncogenes were found to be commonly altered in tumors at frequencies between 12% and 60%. These were c-myc, c-myb, c-ras-Ha, c-erbB-1 and c-erb-B-2. Alterations in c-erbB-1 and c-erbB-2 correlated with histologic type of tumor and were more common in advanced cancers. Allelic deletions of c-ras-Ha or c-myb were frequently observed in primary tumors which recurred or progressed after surgery (five of six). Analysis of protooncogenes may provide insights into the pathogenesis of lung cancer and may aid in predicting clinical behavior. PMID: 3677003 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 497: Nippon Rinsho. 1987 Dec;45(12):2887-92. [Oncogenes and its products in hematopoietic malignancies] [Article in Japanese] Naoe T, Yamada K, Shiku H, Kurosawa Y. PMID: 3328801 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 498: J Immunol. 1987 Dec 1;139(11):3822-7. Differential expression of the c-myb proto-oncogene marks the pre-B cell/B cell junction in murine B lymphoid tumors. Bender TP, Kuehl WM. National Cancer Institute-Navy Medical Oncology Branch, Bethesda, MD 20814. A series of murine B lymphoid tumor cell lines which are representative of the pre-B cell, immature and mature B cell, and plasma cell stages of B cell development have been examined for expression of c-myb proto-oncogene mRNA. The pre-B cell lymphoma cell lines express equivalent high steady state levels of c-myb mRNA. In contrast, the B cell lymphoma and plasmacytoma cell lines express steady state c-myb mRNA at levels which are 0.005 to 0.1 times that of the pre-B cell lymphoma lines. These results correlate high levels of c-myb mRNA expression with the pre-B cell stage of development. Subclones of the 1881 pre-B cell lymphoma which express K light chain and are surface IgM-positive as well as two types of hybrid B lymphoid cell lines have been used to demonstrate that surface immunoglobulin expression is not sufficient to result in the down-regulation of c-myb mRNA levels or changes in the expression N-myc mRNA, lambda 5 mRNA, or the BP-1 surface antigen which are markers of the pre-B cell stage of development. Thus, changes in the expression of genes which are independent of immunoglobulin expression are associated with transition from the pre-B cell to the immature B cell stage of development. PMID: 3316389 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 499: Cancer Res. 1987 Dec 1;47(23):6236-42. Amplification and expression of protooncogenes in human small cell lung cancer cell lines. Kiefer PE, Bepler G, Kubasch M, Havemann K. Institute of Cancer Research and Molecular Biology, Philipps-University Marburg, West Germany. Amplification and expression of 16 protooncogenes were examined in 12 established small cell lung cancer (SCLC) cell lines. Seven of 12 cell lines showed a 20- to 35-fold amplification of the c-myc oncogene, 3 cell lines showed an 80- to 130-fold amplification of N-myc oncogene, and one cell line had a simultaneous amplification of the c-myb and N-myc oncogene. In this cell line both oncogenes were transcriptionally highly active at the same time. A variant subpopulation of SCLC expressed an 8.5-kilobase v-fms homologous transcript at high levels but without amplification of the c-fms gene. All cell lines examined had similar RNA levels of the N-ras, Ki-ras, Ha-ras, and c-raf1 oncogenes. DNA amplification, however, was undetectable. The protooncogenes c-fes, c-fos, and c-erbB were expressed very weakly and the transcripts of the oncogenes c-mos, c-sis, c-erbA, c-src, and c-abl were not observed in any of the 12 SCLC-cell lines. From these data we conclude that beyond the oncogenes myc and myb, oncogenes whose gene products are GTP binding proteins and phosphokinases may also be necessary to develop and keep the malignant state of SCLC. The v-fms homologous transcript found may be involved in the transition of the classic cell type to the variant cell type of SCLC. PMID: 2824028 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 500: Virus Genes. 1987 Nov;1(1):35-47. High affinity interleukin 2 receptors in HTLV-1-infected T cells can mediate signals for gene expression. Sakitani M, Nakamura M, Fujii M, Sugamura K, Hinuma Y. Institute for Virus Research, Kyoto University, Japan. The expression of transcripts of the c-myb and c-myc protooncogenes and the interleukin 2 receptor (IL-2R) gene in human T cells infected with human T-cell leukemia virus type 1 (HTLV-1) after exposure to interleukin 2 (IL-2) were examined. Infection with HTLV-1 is known to be associated with constitutive expression of IL-2R, although infected cells do not require IL-2 for growth. Northern blot analysis showed that expression of the mRNAs of the c-myb, c-myc, and IL-2R genes were markedly increased by addition of IL-2 into the cultures, indicating that IL-2R transduced signals for gene expression in these cells as in normal T cells. Studies on distinct HTLV-1-infected T cell clones that differed in numbers of high-affinity IL-2R, showed that the extents of increase in mRNA expression by IL-2 were correlated with the number of high-affinity IL-2R. This correlation was confirmed by demonstration that the levels of mRNA expression were proportional to the numbers of IL-2-bound high-affinity but not low-affinity receptors. Thus, the signals induced by IL-2 for gene expression may be through high-affinity IL-2R. PMID: 3509878 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 501: Anticancer Res. 1987 Nov-Dec;7(6):1117-23. Aberrant oncogene expression in uncultured human sarcoma and melanoma. Shin DM, Gupta V, Donner L, Chawla S, Benjamin R, Gutterman J, Blick M. Department of Medical Oncology, University of Texas M.D. Anderson Hospital and Tumor Institute, Houston 77030. Protooncogenes have the ability to induce and/or maintain the transformed state when they are overly expressed or altered by mutation or gene rearrangement. To study the possible involvement of these cellular oncogenes in the neoplastic transformation, we have analyzed their expression in 44 fresh samples obtained from primary, recurrent, or metastatic tumors from patients with a variety of sarcomas and a melanoma. Our analysis was carried out by the northern blot technique using poly (A)+ RNA hybridized with human cellular DNA probes. A normal 2.3-kb c-myc transcript was observed almost universally at various levels. A normal c-k-ras transcript of 5.2-kb was detected at a low level in most of the samples. In three samples we detected aberrant c-k-ras transcripts of 7.0 and 8.5-kb, while in two other samples we found an aberrant lower-molecular-weight transcript of 1.4-kb. N-myc was expressed in only three samples, and in all instances, the transcripts were aberrant (more than 10-kb). A normal 3.7-kb c-sis transcript was expressed at a low level in most of the sarcomas and the melanoma but was uniquely overexpressed in giant cell tumors of bone. C-fos (2.2-kb) was expressed at a low level in almost half of the samples; c-myb was never expressed. We conclude that c-k-ras, n-myc, c-sis, and c-myc are aberrantly or overexpressed in sarcoma/melanoma, and their activation may play a role in the transforming events leading to development and/or progression of these tumors. PMID: 3442409 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 502: Biochem J. 1987 Nov 1;247(3):701-6. Proto-oncogene expression in proliferating and differentiating cardiac and skeletal muscle. Claycomb WC, Lanson NA Jr. Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, New Orleans 70112. We have examined the expression of 13 proto-oncogenes in proliferating and terminally differentiated cardiac and skeletal muscle. Total RNA was prepared from intact ventricular cardiac-muscle tissue and from purified ventricular cardiac-muscle cells of neonatal and adult rats and from cultured proliferating and terminally differentiated L6A1 rat skeletal-muscle cells. cDNA probes for histone H4, thymidine kinase, myosin heavy chain and M-creatine kinase were used to assess cellular proliferation and differentiation. Oncogenes c-myc, c-raf, c-erb-A, c-ras-H, c-ski, and c-sis were expressed in both proliferating and differentiated cardiac muscle tissue and cells, whereas c-myb expression was not observed in either. c-src was expressed only in neonatal cardiac muscle tissue and cells. c-fms, c-abl, and c-ras-K were expressed in tissue from both neonatal and adult animals but only in purified cells from neonatal animals. c-fes/fps was expressed only in neonatal cardiac muscles cells. c-fos expression was not observed in cardiac-muscle tissue from either neonatal or adult rats, but surprisingly was abundantly expressed in freshly isolated cardiac-muscle cells from animals of both ages. These results emphasize that biochemical analysis using intact cardiac-muscle tissue may not necessarily reflect muscle-specific cell processes. They also show that the expression of c-fos can be activated by the cell isolation procedure. c-myc, c-ski, c-ras-H, c-ras-K, c-abl, c-raf and c-erb-A were expressed in both proliferating and terminally differentiated skeletal-muscle cells, whereas c-myb, c-fos, c-src and c-fms transcripts were observed only in proliferating cells. c-fes/fps and c-sis were not expressed in dividing or fused skeletal-muscle cells. These results demonstrate unique tissue and cell-specific patterns of proto-oncogene expression and suggest that these genes may be involved with the regulation of cellular proliferation and terminal differentiation in striated muscle. PMID: 2447874 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 503: Cancer Res. 1987 Oct 15;47(20):5266-9. Expression of c-myb protooncogene and other cell cycle-related genes in normal and neoplastic human colonic mucosa. Torelli G, Venturelli D, Colo A, Zanni C, Selleri L, Moretti L, Calabretta B, Torelli U. Center for Experimental Haematology, University of Modena, Italy. The expression of c-myb, c-myc, histone H3, and ornithine decarboxylase genes was examined by Northern blot analysis in the normal and neoplastic mucosa of ten subjects affected by colon cancer. The mRNA levels of c-myb protooncogene were detected at low levels in all normal samples but were increased in the neoplastic mucosa of six cases in comparison to the normal counterpart. In five of these six cases the mRNA levels of c-myc, histone H3, and ornithine decarboxylase mRNAs were also increased, suggesting that there is a relation between the high expression of c-myb and the fraction of cycling neoplastic cells. PMID: 3652034 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 504: Cell. 1987 Oct 9;51(1):41-50. v-myb dominance over v-myc in doubly transformed chick myelomonocytic cells. Ness SA, Beug H, Graf T. Differentiation Programme, European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany. Chick myelomonocytic cells transformed by the v-myc oncogene resemble mature macrophages; those transformed by v-myb or v-myb,ets exhibit an immature phenotype. We have analyzed whether these oncogenes are capable of altering the differentiation phenotype of transformed cells by introducing both v-myc plus either v-myb or v-myb,ets into the same cells. Surprisingly, the doubly transformed cells were found to be essentially indistinguishable from cells transformed by v-myb or v-myb,ets alone even when they expressed a high level of v-myc protein. These results demonstrate that v-myb is dominant over v-myc and that, while v-myc induces cell proliferation without affecting differentiation, v-myb induces in the same target cells both proliferation and a block or reversal of differentiation. PMID: 2820586 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 505: J Immunol. 1987 Oct 1;139(7):2143-8. Differential expression of nuclear proto-oncogenes in T cells triggered with mitogenic and nonmitogenic T3 and T11 activation signals. Shipp MA, Reinherz EL. Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA. The relationship between induction of nuclear proto-oncogenes and cellular proliferation is not fully understood. To better define this relationship, we have studied c-fos, c-myc, and c-myb mRNA induction in T lymphocytes where early and late activation events have been clearly delineated. In T cells, initial activation from G0 to G1 results from stimulation of either the antigen/major histocompatibility complex receptor (T3-Ti) or the T11 structure; further cycle progression and proliferation follow interaction of interleukin 2 (IL-2) with the IL-2 receptor. These events can be dissected with monoclonal antibodies to T3 or T11 which cause early activation but differ in their ability to initiate IL-2-dependent cycle progression and proliferation. In T lymphocytes triggered through either T3-Ti or T11, c-fos is induced with a nonmitogenic activation signal whereas c-myb is only induced with a mitogenic signal capable of triggering IL-2 and IL-2 receptor expression. Furthermore, c-myc induction is biphasic and associated with both early and late activation events. Early c-myc, like c-fos, is induced with a nonmitogenic signal. In contrast, induction of late c-myc, like that of c-myb, requires a mitogenic signal. Thus, appearance of c-fos and initial c-myc mRNA seem to be early responses to membrane signaling whereas late c-myc and c-myb are more directly associated with actual cellular proliferation. That nonmitogenic stimulation of T cells via T3-Ti not only abrogates T11-mediated proliferation but also eliminates late c-myc and c-myb transcription further supports this notion. PMID: 2821108 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 506: J Immunol. 1987 Sep 15;139(6):2075-80. Effects of anti-proliferative cyclic AMP on interleukin 2-stimulated gene expression. Farrar WL, Evans SW, Rapp UR, Cleveland JL. Elevation of intracellular cyclic adenosine 3':5' monophosphate (cAMP) inhibits interleukin 2 (IL-2)-stimulated proliferation of a murine cytotoxic cell clone, CT6. The effects of antiproliferative dosages of stable cAMP-derivative, 8-bromoadenosine 3':5'-monophosphate (8-Br-cAMP), on steady state mRNA expression stimulated by IL-2 was examined. IL-2 stimulated mRNA accumulation of three nuclear proto-oncogenes c-fos, c-myc, and c-myb. 8-Br-cAMP alone stimulated c-fos, c-myb, and IL-2 receptor mRNA accumulation as determined by Northern blot analysis. 8-Br-cAMP, however, markedly inhibited c-myc expression stimulated by IL-2. Furthermore, although c-fos and IL-2 receptor mRNA expression was potentiated by 8-Br-cAMP, suppression of protein synthesis was seen. We show that antiproliferative cAMP stimulates similar mRNA expression as does IL-2, with the exception of c-myc. Although a comparative stimulation of steady state mRNA accumulation of some genes occurs, cAMP may profoundly effect protein synthesis. cAMP, therefore, acts on multiple targets involved in the macromolecular events stimulated by IL-2. PMID: 3040863 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 507: Hokkaido Igaku Zasshi. 1987 Sep;62(5):798-807. [Analysis of c-onc genes in choriocarcinoma cells] [Article in Japanese] Fujino T. Department of Obstetrics and Gynecology, Hokkaido University School of Medicine, Sapporo, Japan. Regulatory or structural alterations of c-onc genes including amplification, rearrangement and point mutation was implicated in the causation of various malignant tumors. However, such changes of molecular levels have not been reported so far in choriocarcinoma cells. In the present study, thus, 5 choriocarcinoma cell lines were analyzed by hybridization using 16 oncogene probes. By Southern blot hybridization of DNA extracted from these cells, 8 fold amplification of c-myc gene and rearrangement of c-fms gene were shown in ENAMI cells, although the role of these alterations remained unknown. Northern blot hybridization performed simultaneously demonstrated multiple expression of c-onc genes. 4 choriocarcinoma cell lines (HCCM, CHl, CCl, ENAMI) expressed at least 11 c-onc genes (H-ras, K-ras, N-ras, c-myc, N-myc, fos, fms, src, yes, erb B and raf); though the degree of expression of H-ras, C-myc, erb B and fms in these cells was either similar or enhanced as compared with normal fibroblast, the expression of two c-onc genes (N-myc and fos) was extremely enhanced. However, expression of K-ras and myb was either low or not detected. The multiple expression of c-onc genes seems to reflect partly on growth advantages of trophoblast. Transfection assay using NIH3T3 cells failed to form any transformed foci. Since choriocarcinoma cells which derived from the transformation of trophoblast of complete mole possess the genetic characteristics identical to the one of cells of complete mole, chromosomal instability was assumed to play a major role for multiple oncogene expression in choriocarcinoma cells. PMID: 3692432 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 508: J Immunol. 1987 Sep 1;139(5):1550-6. Direct activation of human resting T cells by IL 2: the role of an IL 2 receptor distinct from the Tac protein. Bich-Thuy LT, Dukovich M, Peffer NJ, Fauci AS, Kehrl JH, Greene WC. High concentrations of interleukin 2 (IL 2) were shown to produce a delayed but pronounced proliferation of purified resting T cells in the apparent absence of other activation signals. Because these stimulatory effects of IL 2 occurred in the absence of detectable Tac+ cells, the possibility that IL 2 might be initially interacting with an IL 2 binding protein distinct from the Tac protein was studied. Chemical cross-linking studies with 125I-IL 2 revealed the presence of an IL 2 binding protein distinct from the Tac protein on the surface of these unstimulated T cells. This second IL 2 receptor has an estimated molecular size of 70,000 daltons, lacks reactivity with the anti-Tac antibody, and appears to be identical to the p70 protein recently proposed as a component of the high affinity IL 2 receptor. Scatchard analysis of IL 2 binding assays performed with the unactivated T cells revealed approximately 600 to 700 p70 sites per cell and an apparent Kd of 340 pM. These data indicate that the p70 protein present on resting T cells binds IL 2 with an intermediate affinity compared with the previously recognized high and low affinity forms of the receptor and may account for the high concentration of IL 2 needed to induce resting T cell proliferation. To investigate the early biologic consequences of IL 2 binding to the p70 protein, potential changes in the expression of genes involved in T cell activation were examined. Northern blotting revealed the rapid induction of c-myc, c-myb, and Tac mRNA after stimulation of resting T cells with a high concentration of IL 2. The anti-Tac antibody did not inhibit IL 2 induced expression of these genes, suggesting that the p70 protein rather than the Tac antigen or the high affinity IL 2 receptor complex mediated this signal. However, in contrast to these early activation events, the anti-Tac antibody significantly inhibited IL 2 induced T cell proliferation. This finding implicates the high affinity form of the IL 2 receptor in the proliferative response of the IL 2 activated T cells. Thus these data support a two step model for the induction of resting T cell proliferation by high doses of IL 2 involving the initial generation of an activation or "competence" signal through the p70 protein and a subsequent proliferation or "progression" signal through the high affinity form of the receptor. PMID: 3040856 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 509: Mol Biol Med. 1987 Aug;4(4):213-27. Specificity of proto-oncogene amplification in human malignant diseases. Masuda H, Battifora H, Yokota J, Meltzer S, Cline MJ. Department of Medicine, University of California, Los Angeles 90024. DNAs from 253 fresh human tumors of 38 different types were hybridized with 17 different oncogene probes. The analysis demonstrated unique associations between amplification of specific oncogenes and specific types of tumors. In a large number of cases it was determined that amplified oncogenes occurred in 10 to 20% of tumors with the following specific associations: c-myc in adenocarcinomas, squamous carcinomas and sarcomas but not hematologic malignancies; c-erbB2 in adenocarcinomas, particularly breast cancers; c-erbB1 in squamous carcinomas; N-myc in neuroblastomas. A small number of cases suggested other specific associations: amplified c-myb in breast cancers; amplified c-ras-Ha and c-ras-Ki in ovarian carcinomas. In addition, there was a correlation between amplification of c-myc and the clinical stage of adenocarcinomas, and amplification of c-erbB2 and the clinical stage and lymph node involvement of breast cancers. PMID: 3670047 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 510: Leukemia. 1987 Aug;1(8):597-602. Proto-oncogene expression in human normal bone marrow. Evinger-Hodges MJ, Dicke KA, Gutterman JU, Blick M. Department of Hematology, U.T. M.D. Anderson Hospital & Tumor Institute, Houston 77030. We and other investigators have previously reported our findings on oncogene expression in human leukemia in an attempt to study the possible involvement of these genes in the leukemic state. An important shortcoming of these studies has been the lack of information on the expression of these genes in normal hematopoietic cells. To address this question we analyzed both the transcript size and level of expression of six oncogenes in fresh hematopoietic cells obtained from hematologically normal individuals and compared the results to those found in fresh samples obtained from patients with various forms of leukemia (acute myelogenous leukemia, acute lymphocytic leukemia, and chronic myelogenous leukemia). We found low level expression of c-myc, c-myb, c-fes, and c-raf in normal bone marrow in sharp contrast to the high levels of expression found in some forms of leukemia. C-fos was highly expressed in both normal bone marrow and certain leukemias. We were unable to detect c-sis expression in our normal samples. With the exception of c-fes, there was no variation in transcript size when comparing normal and leukemic samples. Having defined the transcript sizes and levels of expression for these proto-oncogenes in normal hematopoietic cells, we know that aberrant transcript size for the genes we have studied is not a common event in leukemias. The levels of expression, however, vary widely between normal hematopoietic cells and leukemia as well as between different types of leukemia. PMID: 3669772 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 511: J Natl Cancer Inst. 1987 Jul;79(1):67-76. Changes in proto-oncogene expression associated with reversal of macrophage-like differentiation of HL 60 cells. Studzinski GP, Brelvi ZS. Prolonged exposure to 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] of 2 sublines (AB-2 and AB-26) of human promyelocytic HL 60 leukemia cells produced increased adherence of the cells to the culture substratum. Advantage was taken of this property to separate physically a population of cells highly enriched in macrophage-like forms. When these differentiated cells were placed in culture medium free of 1,25(OH)2D3, there was a rapid reversal of the features of the differentiated phenotype, monitored by the loss of alpha-naphthyl butyrate esterase activity and the loss of adherence to the substrate. The reversal was accompanied by the resumption of normal rates of DNA synthesis, mitosis, and reaccumulation of c-myc and c-myb transcripts. The levels of transcripts of oncogenes c-fos and c-fms, which became abundant in the phenotypically differentiated cultures, declined along with the loss of adhesiveness and reversion to more primitive myeloblastic forms. These changes in proto-oncogene expression became evident before cell proliferation resumed, thereby excluding the diluting effect of the outgrowth of undifferentiated cells. It is concluded that in this system there is no firm commitment to terminal, as opposed to early, differentiation in the great majority of the cells and that the expression of the monocytic maturation-associated genes c-fos and c-fms is down-regulated when macrophage-like cells dedifferentiate. This strengthens the case for an association between macrophage differentiation and the expression of oncogenes c-fos and c-fms. PMID: 3474450 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 512: J Clin Oncol. 1987 Jul;5(7):999-1006. Proto-oncogene abnormalities in human breast cancer: correlations with anatomic features and clinical course of disease. Cline MJ, Battifora H, Yokota J. DNAs from fifty-three primary breast cancers were hybridized with 16 different proto-oncogene or oncogene probes. Abnormalities of one or more of five proto-oncogenes were found in fifty-eight percent of tumors at the time of mastectomy. Amplification of c-myc and c-erbB-2, and allelic deletions of c-ras-Ha and c-myb were the most common abnormalities. The presence of altered proto-oncogenes correlated with clinical stage of the cancers. Fifteen of 43 evaluable tumors of stages I to III recurred, and four of five evaluable stage IV tumors progressed within 16 to 24 months of surgery. All but one of the cancers that recurred or progressed had detectably altered proto-oncogenes (P less than .001). Analysis of proto-oncogenes may have prognostic value in breast cancer. PMID: 3474361 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 513: Int J Cell Cloning. 1987 Jul;5(4):255-66. Oncogene expression in myelopoiesis. Rowley PT, Skuse GR. Oncogenes are a class of genes hypothesized to be causally related to neoplasia. To date, specific oncogenes have been recognized chiefly by their ability to transform test cells to a neoplastic phenotype. This has been accomplished largely through mutational analysis of the genotype of retroviruses or through the analysis of tumor cell DNA by in vitro transfection of rodent fibroblasts. Oncogenes are believed to arise by some genetic alteration from normal cellular genes called proto-oncogenes. Although the normal function of most proto-oncogenes is unknown, it has been proposed that they may function as tissue-specific and temporally specific regulators of differentiation. The role of oncogenes in lymphoid malignancies has been extensively analyzed. Less is known about their role in myeloid leukemias and especially in normal myelopoiesis. Space limitations permit discussion of only salient features of a limited number of oncogenes; we have arbitrarily selected myc, myb, fos, fms, fes, sis, and abl. Publication Types: Review PMID: 3305725 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 514: Cancer Genet Cytogenet. 1987 Jul;27(1):45-50. Chromosomal abnormalities in a primary small cell lung cancer. Sozzi G, Bertoglio MG, Borrello MG, Giani S, Pilotti S, Pierotti M, Della Porta G. A cytogenetic analysis of a fresh primary tumor specimen of small cell lung cancer showed a del(3)(p14p23) in the majority of metaphases. Additional clonal changes were found in the karyotype. No abnormalities for Ha-ras, Ki-ras, N-ras, myb, or myc were detected by Southern blot analysis of the tumor DNA. Publication Types: Case Reports PMID: 3034398 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 515: Semin Oncol. 1987 Jun;14(2 Suppl 1):192-201. Proto-oncogene expression in HL-60 cells exposed to ara-C. Sato H, Preisler HD. To verify the reported differentiation/maturation-inducing effects of cytosine-beta-D-arabinofuranoside (ara-C, Sigma Chemical Corp, St Louis) on hematopoietic cells, we studied the morphologic changes and patterns of proto-oncogene expression in HL-60 cells that had been exposed to the drug. At the 1 X 10(-7) mol/L concentration of ara-C, approximately 10% of HL-60 cells became nitroblue tetrazolium (NBT) reduction test positive after four days exposure. However, no cells became nonspecific esterase-positive during the culture period. Doses less than 1 X 10(-8) mol/L had virtually no effect on maturation and proliferation of the target cells while doses greater than 1 X 10(-6) mol/L were lethal to HL-60 cells. Cells treated with 1 X 10(-7) mol/L and 1 X 10(-9) mol/L ara-C did not evidence any of the changes in c-myc, c-myb, c-fos, or c-fes that are noted when dimethyl sulfoxide (DMSO) or 12-0-tetradecanoyl phorbol 13-acetate (TPA, Sigma Chemical Corp, St Louis) are used to induce the differentiation of HL-60 cells. In both doses, temporary decreases of the S-phase specific and proliferation related histone H3 gene expression occurred. This phenomenon may be related to an increase in the tendency of these cells to spontaneously differentiate. Because of the possibility of drug inactivation during culture and because HL-60 cells have already matured to the promyelocytic stage, these kinds of experimental systems may be inadequate in in vitro models for low-dose ara-C therapy. PMID: 3296204 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 516: Eur J Cancer Clin Oncol. 1987 Jun;23(6):623-9. Oncogene amplifications, rearrangements, and restriction fragment length polymorphisms in human leukaemia. Boehm TL, Hirth HP, Kornhuber B, Drahovsky D. Zentrum der Biologischen Chemie, Universitat Frankfurt am Main, FRG. We have determined the prevalence of amplification and rearrangements for c-myc, c-myb, c-mos, bcr, c-abl, c-Ha-ras-1, c-N-ras, and c-K-ras-2 in a total of 51 cases of human leukaemia (19 patients with AML, 13 cases with CML, 14 cases with ALL, and 5 cases with CLL). Amplifications at a level of more than 2 two copies per haploid genome are apparently very rare and were found only once for c-myb in a c-ALL patient. Oncogene rearrangements were not found except for bcr, which was rearranged in all cases of CML, and 5 cases of ALL studied. Restriction fragment lengths polymorphisms (RFLPs) were also analysed. A previously described rare 5 kb EcoRI allele at the c-mos locus was absent in our patients. Rare alleles at the c-Ha-ras-1 locus were found to be significantly more prevalent in our patients than in a control group. Transfection experiments revealed no dominant transforming oncogenes in the tumour DNA of 3 patients carrying such rare alleles. PMID: 2888656 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 517: J Immunol. 1987 May 15;138(10):3495-504. Role of c-myc and other genes in interleukin 2 regulated CT6 T lymphocytes and their malignant variants. Cleveland JL, Rapp UR, Farrar WL. The cloned murine cytotoxic T cell line CT6 solely requires interleukin 2 (IL 2) for viability and cell cycle progression. Treatment of G arrested cultures of CT6 cells with recombinant IL 2 induces the rapid sequential expression of the nuclear proto-oncogenes c-fos, c-myc, and c-myb but does not affect the expression of several cytosolic or membrane-associated proto-oncogenes. A comparison of early genes induced by growth factor treatment of quiescent NIH/3T3 fibroblasts and CT6 cells demonstrated that only c-fos and c-myc induction is shared in the two different lineages. Factor-independent lines derived from CT6 cells show no mitogenic response to IL 2, yet binding of IL 2 with its receptor in the cells was capable of inducing the expression of c-fos and c-myc. In factor-independent cell lines, c-myc was uniformly expressed at high constitutive levels, suggesting that c-myc abrogates growth factor requirements of these cells. The levels of c-myc expression in the factor-independent lines was not due to an autocrine production of IL 2 but may be a consequence of constitutively activated IL 2 receptors. PMID: 3106484 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 518: J Cell Biochem. 1987 May;34(1):31-8. Suppression of tumorigenicity in somatic cell hybrids does not involve quantitative changes in transcription of cellular Ha-ras, Ki-ras, myc, and fos oncogenes. Schafer R, Geisse S, Willecke K. The transcriptional activity of ten cellular oncogenes was analyzed in somatic cell hybrids that had been obtained after fusion of tumorigenic Chinese hamster cells and normal mouse fibroblasts. The hybrids showed either the tumorigenic or the nontumorigenic phenotype (suppression of tumorigenicity). Out of ten c-onc genes analyzed, four (c-Ha-ras, c-Ki-ras, c-myc, and c-fos) were found to be transcriptionally active at similar levels in tumorigenic as well as in nontumorigenic (suppressed) hybrids. Thus we conclude that suppression of tumorigenicity in Chinese hamster X mouse somatic cell hybrids does not correlate with quantitative changes in expression of these cellular oncogenes. The remaining six cellular oncogenes (c-abl, c-erb A and B, c-fes, c-myb, and c-sis) were not transcriptionally active in these hybrids. PMID: 3584261 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 519: Gastroenterology. 1987 May;92(5 Pt 1):1174-80. Erratum in: Gastroenterology 1987 Jul;93(1):223. Protooncogene abnormalities in colon cancers and adenomatous polyps. Meltzer SJ, Ahnen DJ, Battifora H, Yokota J, Cline MJ. To determine the frequency and clinical significance of oncogene abnormalities in colon cancer, deoxyribonucleic acids from 45 colon carcinomas and 15 benign adenomas were hybridized with 14 different protooncogene probes. Abnormalities of oncogenes were found in 22% of cancers at the time of resection. Amplification of c-myc or c-erbB-2 and allelic deletion of c-ras-Ha or c-myb were the most frequent abnormalities. The presence of altered oncogenes did not correlate with Dukes' stage, tumor progression, or patient survival after resection. One adenoma had an allelic deletion of the c-myb oncogene which was not seen in either the normal colon or an adjacent carcinoma. These data indicate that the spectrum of altered protooncogenes in colon carcinoma is similar to that of other adenocarcinomas, and that unstable oncogenes can be found before overt malignancy develops. PMID: 3557013 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 520: Oncogene. 1987 May;1(2):223-8. Proto-oncogene expression in cloned T lymphocytes: mitogens and growth factors induce different patterns of expression. Reed JC, Alpers JD, Scherle PA, Hoover RG, Nowell PC, Prystowsky MB. Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6082. We have compared the effects of a mitogenic lectin, concanavalin A (Con A), and a growth factor, interleukin-2 (IL-2), on the expression of the c-myc, c-fos, and c-myb proto-oncogenes in cloned T lymphocytes. Accumulation of c-myc mRNA was induced by both ConA and IL-2 in these cells. In contrast, expression of c-fos was stimulated primarily by ConA, and accumulation of c-myb mRNA was induced predominantly by IL-2. Thus, ConA and IL-2 induce expression of overlapping, but non-identical, sets of proto-oncogenes in T lymphocytes. Investigations with several different cloned T cells revealed that: (1) c-myb is not induced in all T cells stimulated to grow, indicating that its expression may not be absolutely required for their proliferation; and (2) expression of c-myc, even in combination with c-fos, can be insufficient for growth, demonstrating functional differences between cellular and viral oncogenes in T cells. These observations provide insight into the roles of the c-myc, c-fos, and c-myb proto-oncogenes in normal T cell responses. PMID: 3501855 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 521: Blood. 1987 May;69(5):1542-5. Expression of c-fos, c-myb, and c-myc in human monocytes: correlation with monocytic differentiation. Lee J, Mehta K, Blick MB, Gutterman JU, Lopez-Berestein G. Terminal differentiation of human monocytic leukemia cells (THP-1 cells) was associated with the induction of c-fos, the down regulation of c-myb, and no significant change in the level of c-myc expression. Gamma interferon, which resulted in a slight decrease in c-myb but no change in c-fos or c-myc expression, had a transient antiproliferative effect without a morphological or functional differentiation of THP-1 cells. Resting human peripheral blood monocytes have a high c-fos, a low c-myc, and no detectable c-myb expression. These findings suggest that a switch in c-fos/c-myb expression is associated with the terminal differentiation of cells of the monocytic lineage. PMID: 3105625 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 522: J Cell Physiol. 1987 Apr;131(1):43-9. Coordinate expression of c-myc, c-myb, and histone H4 genes in reversibly differentiating HL 60 cells. Brelvi ZS, Studzinski GP. The expression of oncogenes c-myc and c-myb in human leukemic cells HL 60 was compared to the expression of histone H4 gene, known to be cell-cycle dependent. Steady-state levels of mRNA transcribed from these genes were determined by simultaneous hybridization of Northern transfers with four probes, and the rates of gene expression were measured by nuclear transcription ("run-on") assays. Expression of genes c-myc, c-myb and histone H4 varied coordinately and in parallel with the rates of DNA synthesis, while the rates of total and ribosomal RNA synthesis, the expression of gene c-Ha-ras, unrelated to proliferation of these cells, and gene p 72, a constitutively expressed human gene, were unchanged. Further, the levels of c-myc and c-myb mRNA but not p 72 mRNA were higher in cell populations enriched for S phase cells. Thus, transcription of genes c-myc and c-myb in HL 60 cells appears to be linked to DNA replication in a manner previously demonstrated for core histone gene expression. PMID: 3032993 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 523: J Virol. 1987 Apr;61(4):1164-70. Dsi-1, a region with frequent proviral insertions in Moloney murine leukemia virus-induced rat thymomas. Vijaya S, Steffen DL, Kozak C, Robinson HL. Dsi-1 is a region of chromosomal DNA that underwent proviral insertion in 3 of 24 Moloney murine leukemia virus-induced rat thymomas. In one of these tumors, a provirus is also integrated adjacent to the proto-oncogene c-myc. The proviruses in Dsi-1 have been characterized and appear to be complete. The proviruses were located within a 2-kilobase region that contained four prominent DNase I-hypersensitive sites. These hypersensitive sites were observed in Moloney murine leukemia virus-induced thymomas but not in NRK cells. The region of Dsi-1 immediately 3' to the insertions cross-hybridized with human and chicken DNA, indicating that it contains highly conserved sequences. No evidence could be found for the expression of this highly conserved region. Dsi-1 was mapped to mouse chromosome 4. This location demonstrates that Dsi-1 is different from 16 of the known proto-oncogenes (c-abl, c-erbA c-erbB, c-ets-1, c-ets-2, c-fes, c-fos, c-myb, c-myc, c-raf, A-raf, c-Ha-ras, c-Ki-ras, N-ras, c-sis, and c-src) and 12 cellular regions of tumor-associated integrations in retrovirus-induced tumors (c-erbB, Fis-1, int-1, int-2, Mis-1/pvt-1, Mlvi-1, Mlvi-2, c-mos, c-myb, c-myc, Pim-1, and c-Ha-ras). Hybridization experiments indicated that Dsi-1 is probably different from five additional proto-oncogenes (c-fgr, c-fms, c-mos, neu, and c-yes) and from two additional frequent integration regions (lck and Mlvi-3). PMID: 3029411 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 524: Cancer Res. 1987 Feb 15;47(4):1052-7. Inhibition of messenger RNA transcriptional activity in ML-1 human myeloblastic leukemia cell nuclei by antiserum to a c-myb-specific peptide. Ishikura H, Honma Y, Honma C, Hozumi M, Black JD, Kieber-Emmons T, Bloch A. Antiserum to a synthetic peptide that defines a hydrophilic region within the putative c-myb translation product was prepared in the rabbit. In lysates from exponentially growing ML-1, human myeloblastic leukemia cells, the antiserum ("anti-myb") reacted with five proteins of Mr 58,000, 75,000, 85,000, 90,000 and 105,000. Of these, only p75 and a trace of p85 were detected, by immunoblotting, in extracts derived from ML-1 cell nuclei. The proteins p58, p75 and p90 were present in readily detectable amounts only in the relatively immature myeloid cell lines ML-1 and HL-60, whereas in the more mature myeloid cell line THP-1 and in the lymphoid line BALL-1 only traces of these proteins were found. p85 and p105 were detected in lysates from all cell lines tested, including myeloid and lymphoid leukemia cells and mouse 3T3 cells. In lysates from ML-1 cells induced to differentiate to monocyte/macrophages or to granulocytes, the concentrations of p58 and p75 decreased in parallel with the cell population moving to maturity; in completely mature populations these two proteins were no longer detectable. In ML-1 cells arrested in G1 by serum depletion, the amount of p58 and p75 and to a smaller extent that of p90 was decreased, whereas the concentration of p85 and p105 remained unchanged. In nuclei from exponentially growing ML-1 cells, the antiserum or its derived immunoglobulin fraction ("anti-myb IgG") inhibited mRNA transcriptional activity by 30%. DNA synthesis was not affected. In contrast, in nuclei from differentiated ML-1 cells, the mRNA transcriptional activity was not significantly inhibited by anti-myb IgG. Similarly, in nuclei from ML-1 cells arrested largely in G1 by serum depletion for 2 days, mRNA transcriptional activity was inhibited by only 11%. Upon supplementation with serum, the mRNA transcriptional activity inhibitable by anti-myb IgG increased in parallel with the increasing rate of cell growth. The difference in total mRNA transcriptional activity observed in nuclei from cells of different growth rate was accounted for by the difference in transcriptional activity inhibitable by anti-myb IgG.(ABSTRACT TRUNCATED AT 400 WORDS) PMID: 3542199 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 525: Biochem Biophys Res Commun. 1987 Feb 13;142(3):932-8. The expression of oncogenes in human developing liver and hepatomas. Zhang XK, Huang DP, Chiu DK, Chiu JF. Oncogene expression was examined in the human fetal liver and human hepatomas. Erb (B), erb (A+B), Ha-ras, myc, fos and fms oncogene expression elevated in certain stages of fetal liver development and in hepatoma as compared to the normal adult human liver. In contrast, rel, src, mos, sis, myb, Ki-ras and bas oncogenes showed no apparent change of their mRNA levels during fetal liver development and in hepatoma. Further study of erb B oncogene expression in human cirrhotic liver and hepatoma demonstrated a strong correlation between erb B expression and alteration of its gene structure. PMID: 3030308 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 526: Proc Soc Exp Biol Med. 1987 Feb;184(2):186-90. IL-2 modulation of murine T-cell oncogene expression. Seldin MF, Mountz JD, Mushinski JF, Smith HR, Steinberg AD. C-myb, a cellular oncogene associated with normal thymic development, was found to be highly expressed in four interleukin 2 (IL-2)-independent T-cell lines, but not in two of three IL-2-dependent T-cell lines. The IL-2-dependent lines, HT2 and CTLL-2, were found to have low levels of c-myb mRNA in the presence of IL-2. However, short-term IL-2 depletion resulted in at least fivefold increases in c-myb message. Add-back of IL-2 after 30 hr IL-2 depletion of CTLL-2 cells resulted in return to baseline low-level c-myb mRNA. Expression of the oncogenes myc, bas, raf, and abl as well as the T-cell genes Thy-1 and CT beta did not parallel that of c-myb. These studies indicate that removal of a growth factor can result in increased levels of a specific cellular oncogene and that two nuclear protooncogenes (c-myb and c-myc) are expressed differentially during cell growth. These results may help to explain aspects of intrathymic T-cell differentiation where there is very high c-myb expression in the face of limiting amounts of growth factors such as IL-2. PMID: 3492715 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 527: Br J Haematol. 1987 Feb;65(2):165-70. Simultaneously increased expression of the c-myc and mu chain genes in the acute blastic transformation of a chronic lymphocytic leukaemia. Torelli UL, Torelli GM, Emilia G, Selleri L, Venturelli D, Artusi T, Donelli A, Colo A, Fornieri C. A B-cell chronic lymphocytic leukaemia terminated, 5 years from the onset, with a blast crisis. Karyotype analysis showed that the terminal lymphoblastic population evolved from the original B lymphocytic clone. The levels of expression of several oncogenes, as well as the mu chain gene, were assayed by Northern blot hybridization analysis of RNA extracted from the lymphoid populations before and after the 'acute transformation'. A seven- to eight-fold increase in the expression of c-myc and mu chain genes was observed in the blast population. c-myb, c-fes, c-Haras were not expressed either before or after the blastic transformation. Publication Types: Case Reports PMID: 3103669 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 528: Cancer Res. 1987 Jan 15;47(2):527-31. Transformation of Epstein-Barr virus immortalized human B-cells by chemical carcinogens. Kessler DJ, Heilman CA, Cossman J, Maguire RT, Thorgeirsson SS. Epstein-Barr virus-immortalized human lymphocytes were used to analyze the transition from the benign hyperproliferative to the malignant transformed state. Treatment with N-acetoxy-2-acetylaminofluorene, a potent frameshift mutagen, induced conversion of the Epstein-Barr virus immortalized lymphocytes into high-grade "immunoblastic lymphomas" on injection into athymic mice, whereas injection of the untreated, original cells did not. The tumor cells were all of the B-cell lineage as determined by the presence of surface immunoglobulins and antigens detected by B-cell specific antibodies to B1 and B4, and the absence of the T-cell-specific markers, 3A1 and LEU-1. The N-acetoxy-2-acetylaminofluorene-induced tumor lines displayed abnormal diploid to tetraploid karyotypes. The fewest chromosomal rearrangement, excluding tetraploidy, observed in these chemically induced lymphomas involved a deletion in chromosome 6, and additions on both chromosomes 16 and 4. Neither major rearrangements nor amplifications were found for K-ras, H-ras, N-ras, c-myc, Blym, and c-myb in these tumor lines. PMID: 3491677 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 529: Nucleic Acids Res. 1987 Jan 12;15(1):87-103. Replication of proto-oncogenes early during the S phase in mammalian cell lines. Iqbal MA, Chinsky J, Didamo V, Schildkraut CL. Members of several classes of proto-oncogenes replicate during the first third of S-phase in two human (K562 erythroleukemia and HeLa), one Chinese hamster (CHO) and eight mouse cell lines. These cell lines exhibit a variety of specialized functions characteristic of pre-B and B cells, T cells and erythroid cells. The proto-oncogenes studied include fos, myc, myb, abl, fes, fms, mos, raf, rel, sis, Ha-ras, Ki-ras, and N-ras. In K562 cells, amplified and rearranged c-abl genes show a pattern of temporal replication during S that is similar to the pattern observed for the 5' breakpoint cluster region (bcr) and the amplified C lambda light chain immunoglobulin genes. The c-Ki-ras related sequences in CHO cells provide one example of late replicating proto-oncogene sequences that are present in multiple copies. The cellular gene N-myc replicates late during S in some of these cell lines. In three pre-B cell lines in which N-myc specific transcripts have been detected, N-myc replicates earlier in the S phase than in the other cell lines studied here. PMID: 3469620 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 530: Dermatologica. 1987;175(6):296-9. Expression of c-Myc, c-Myb, c-Erb-B and c-H-Ras oncogene mRNAs in fibroblasts cultured from psoriatic patients. Basset N, Vie A, Blanchard JM, Guilhou JJ. Clinique de Dermatologie-Phlebologie, Hopital Saint-Charles, Montpellier, France. The abnormally high rate of proliferation described in cultured psoriatic fibroblasts could result from inappropriate expression of cellular oncogenes (c-onc) associated to the control of cell division. Four c-onc (c-Myc, c-Myb, c-Erb-B, c-H-Ras) were studied in cultured fibroblasts from lesional and nonlesional psoriatic skin (n = 6) and compared with normal subjects (n = 3). RNA was analyzed by hybridization with nick-translated cloned human DNA probes after extraction by the guanidinium thiocyanate/LiCl procedure, electrophoresis and transfer on nitrocellulose. No difference in the level of c-Myc and c-Myb mRNA could be detected in psoriatic skin compared with controls. N-Ras did not give a detectable signal and c-Erb-B exhibited individual variations which were not linked to the disease. These results do not rule out subtle qualitative changes of these genes; moreover, an abnormal mRNA expression of other c-onc remains possible in psoriasis. PMID: 3691904 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 531: Oncogene Res. 1987;2(1):33-48. Common sites of viral integration in lymphomas arising in AKXD recombinant inbred mouse strains. Mucenski ML, Gilbert DJ, Taylor BA, Jenkins NA, Copeland NG. NCI-Frederick Cancer Research Facility, BRI-Basic Research Program, Frederick, Maryland 21701. Lymphomas from 21 AKXD recombinant inbred mouse strains were analyzed for retrovirally induced rearrangements in seven known or putative proto-oncogene loci. Among the rearrangements detected in the 258 lymphomas screened, most rearrangements appeared to be caused by viral integration. Rearrangements were detected in the Myc, Pvt-1, Pim-1, Mlvi-1, Mlvi-2, and Fis-1 loci, but not in the Myb locus. Seven lymphomas contained rearrangements in two loci. Nearly 90% of the rearrangements were observed in T cell lymphomas; few were detected in B cell or myeloid tumors. Rearrangements in Pvt-1, Fis-1, Mlvi-1, and Mlvi-2 were identified only in T cell lymphomas. Alterations in the Myc and Pim-1 loci, although occurring predominantly in T cell lymphomas, were occasionally detected in other types of lymphoma. These data suggest that the repertoire of cellular proto-oncogenes activated by integration of virus into lymphomas may be different for each hematopoietic cell lineage. The AKXD lymphomas represent a useful resource for identifying these sites. PMID: 3505665 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 532: 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] --------------------------------------------------------------- 533: Gene. 1987;54(1):105-11. The cDNA sequence and gene analysis of the human pim oncogene. Zakut-Houri R, Hazum S, Givol D, Telerman A. The putative oncogene pim-1 is frequently activated by provirus insertion in MuLV-induced T cell lymphomas in mice. By analogy with other cellular oncogenes that are similarly activated (e.g., myc, myb, erbB) it is possible that pim-1 may also be involved in some human tumors. To study human pim-1 we cloned and sequenced human pim-1 cDNA clones. The human pim-1 codes for a protein of 313 amino acids (aa) which is highly homologous (94%) to the deduced amino acid sequence of mouse pim-1. All the mouse pim-1 residues which are homologous to protein kinases are conserved in the human pim-1. We also isolated the human pim-1 gene and mapped it relative to the cDNA. The RNA transcript of human pim-1 is approx. 3.0 kb and it is highly expressed in the erythroleukemia cell line K562. PMID: 3475233 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 534: 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] --------------------------------------------------------------- 535: Eksp Onkol. 1987;9(6):11-7. [Chromosome aberrations and cellular antigens] [Article in Russian] S'iakste TG, Erenpreis IaG. A possible role of chromosomal abnormalities in activation of cellular oncogenes is discussed. Data about the types of chromosomal aberrations characteristic of tumours and of expression of oncogenes localized in aberrant chromosomes are compared. For some oncogenes (c-myc, c-myb, c-abl, c-fes, c-fms) a more or less distinct correlation is observed between certain types of chromosomal abnormalities and increase of oncogene expression. On the contrary, one cannot observe such correlation for other group of oncogenes (c-fos, c-ets, c-mos, c-erb-A-1, c-sis, c-src). Chromosomal aberrations are probably one of the mechanisms of cellular oncogene activation during the carcinogenesis. Publication Types: Review Review, Tutorial PMID: 3325265 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 536: Urol Res. 1987;15(6):349-53. Expression of proto-oncogenes in xenografts of human renal cell carcinomas. Karthaus HF, Bussemakers MJ, Schalken JA, Kurth KH, Feitz WF, Debruyne FM, Bloemers HP, Van de Ven WJ. Department of Urology, St. Radboud University Hospital, Nijmegen, The Netherlands. In a recent paper, we described the expression pattern of proto-oncogenes in primary human renal cell carcinoma [12]. To test the possibility of using xenografts as a useful alternative for such studies, we analyzed xenografts of a number of human renal cell carcinomas in nu/nu mice. Xenografts included RC2, RC14, RC21, RC43 and NC65. Northern blot analysis indicated that c-Ras was expressed in all these xenografts. The identity of the ras transcripts in the individual xenografts was further specified as c-Ha-ras, c-Ki-ras or N-ras. Expression of c-myc and the p53 gene was also found in a number of these tumors. Only RC21 failed to express the c-myc or the p53 gene. In all xenografts, a 3.0 kb c-fes/fps mRNA was present. In RC2, RC14, RC21 and RC43, low levels of the 4.8 kb ab 1 transcript were detectable. Transcripts of myb and sis could not be detected in any of the xenografts. The results indicated that the expression pattern of a variety of proto-oncogenes in xenografts of human renal cell carcinomas was similar to that in the primary tumors. PMID: 3324444 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 537: Blood Cells. 1987;13(1-2):277-84. Induced erythroleukemia differentiation: cellular and molecular aspects. Rifkind RA, Sheffery M, Marks PA. DeWitt Wallace Research Laboratories, Memorial Sloan-Kettering Cancer Center, New York. MELC may be induced to terminal erythroid differentiation by HMBA and other agents. Although the mechanism is not known, changes in cell function and gene expression can be identified during an early "latent" period, prior to commitment to terminal differentiation. These include a decrease in diacylglycerol concentration and in Ca+2 and phospholipid-dependent protein kinase C activity, accompanied by suppression of c-myb and c-myc gene transcription, a fall in p53 protein, and an increase in c-fos mRNA. Commitment is first detected by 12 hours and is associated with persistent suppression of c-myb gene transcription. Transcription of the erythroid-specific genes, alpha 1 and beta maj globin, is increased 10- to 30-fold, whereas synthesis of rRNA is suppressed, and there is activation or suppression of a number of additional genes that remain to be characterized. The potential regulatory roles of changes in protein kinase C activity and in proto-oncogene expression in initiating and sustaining the process of differentiation also remain to be elucidated. Publication Types: Review Review, Tutorial PMID: 3311222 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 538: Proc Natl Acad Sci U S A. 1987 Jan;84(1):199-203. Phorbol ester-induced growth arrest of murine myelomonocytic leukemic cells with virus-disrupted myb locus is not accompanied by decreased myc and myb expression. Shen-Ong GL, Holmes KL, Morse HC 3rd. A class of mouse neoplasms termed Abelson virus-induced plasmacytoid lymphosarcomas has previously been found to express abnormal myb transcripts due to a helper virus insertion into the 5' end of the c-myb locus. We have established clonal cell lines from these tumors and have shown that they all express markers characteristic of myelomonocytic, rather than lymphoid, cells. Treatment of the plasmacytoid lymphosarcoma lines with phorbol 12-myristate 13-acetate led to various degrees of growth arrest, presumably due to myelomonocytic differentiation. To date, characterization of myeloid cell lines with varying responses to phorbol 12-myristate 13-acetate has not been reported. The different clonal plasmacytoid lymphosarcoma lines should, therefore, provide a good model to help elucidate the role of altered myb locus and other protooncogenes in myelomonocytic leukemia. Contrary to studies on induced differentiation of myelomonocytic cells with normal myb locus, our results on plasmacytoid lymphosarcoma cells indicate that reduced myb and myc expression may not be obligatory for growth arrest to occur. The present study, however, supports the previous notion that the myb transforming ability may be restricted to cells of the myelomonocytic lineage. In addition, we found that only the more mature cells can undergo prolonged phorbol 12-myristate 13-acetate-induced growth arrest, suggesting that the maintenance of these leukemic cells in their proliferative state, presumably by the myb gene product, can be overcome with appropriate differentiation signal(s). PMID: 3025854 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 539: Int J Cancer. 1986 Dec 15;38(6):821-7. Unsuitability of monoclonal antibodies to oncogene proteins for anti-tumour drug-targeting. Embleton MJ, Habib NA, Garnett MC, Wood C. Monoclonal antibodies (MAbs) to ras, sis, erb-B, src, myb and myc oncoproteins were evaluated for their potential to target anti-cancer drugs to malignant cells. Each antibody was tested for reactivity against both fixed and viable cultured human tumour cells by immunofluorescence, and all reacted against a variety of fixed tumour cell preparations. Reactions were also observed against fixed non-malignant cells. None, however, reacted significantly with viable cells. Two antibodies (against ras and myc proteins) were tested for their ability to localize to tumour xenografts in nude mice, and conjugates were constructed by linking these antibodies to methotrexate using human serum albumin as an intermediate carrier. Neither antibody localized to tumour in vivo, and the methotrexate conjugates were not significantly cytotoxic for tumour cells in vitro, in contrast to similar conjugates simultaneously prepared with a proven anti-tumour MAb (791T/36). It was concluded that currently available MAbs to oncogene proteins are not suitable vectors for targeting cytotoxic agents to tumour cells. PMID: 3539823 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 540: Cancer Res. 1986 Dec;46(12 Pt 1):6311-5. Mechanism of interaction between antineoplastic agents and natural differentiation factors in the induction of human leukemic cell maturation. Honma Y, Honma C, Bloch A. DNA-specific agents have the capacity to induce the maturation of ML-1 human myeloblastic leukemia cells to monocyte/macrophages if adequate concentrations of fetal bovine serum or mitogen-stimulated human leukocyte-conditioned medium (CM) are present in the culture medium. Fetal bovine serum and CM contain specific differentiation-inducing factors that, in conjunction with the drugs, bring about cell maturation. To examine the mechanism by which this interactive effect occurs, ML-1 cells were exposed to actinomycin D or daunomycin in various combinations with CM, using concentrations at which neither the drug nor CM, when applied individually, induced maturation to a significant extent. Pretreatment for 3 days with drug followed by treatment for 3 days with CM caused maturation of 75% of the cells, as determined by the appearance of Fc receptors. Other markers of differentiation, including alpha-napthyl acetate esterase, acid phosphatase, and morphology, also reflected the increase in maturation. The simultaneous application of drug and CM was equally effective in inducing differentiation. Pretreatment of the cells with CM followed by treatment with drug failed to induce maturation, whereas pretreatment with CM followed by a second application of CM caused the expression of Fc receptors in 62% of the cells. In contrast, pretreatment with drug followed by a second application of drug did not induce differentiation significantly. These results indicate that the drug sensitizes the cells to respond to concentrations of CM to which they would otherwise be refractive. The drug-induced sensitization is reversible. At sensitizing drug concentrations, cell viability was preserved but, as measured by radiolabeling for 1 h, total RNA synthesis was decreased by 38% and mRNA synthesis by 87%. At these drug concentrations, the synthesis of mRNA specified by all seven oncogenes examined (myb, myc, abl, fos, N-ras, sis, erb B) was decreased by 15-60%. The administration of CM subsequent to drug caused a further decrease of some mRNA levels (c-myb, c-myc) but increased the level of others (c-fos). The drug-induced lowering of mRNA levels is considered to inhibit the synthesis of proteins specifically required for G1-S transit and maintenance of the proliferation program, amplifying, thereby, the maturation signal emitted by the differentiation factors present in serum and in CM. As a result, expression of the maturation program is initiated. PMID: 3465437 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 541: Mol Cell Biol. 1986 Dec;6(12):4244-50. Diltiazem inhibits transferrin receptor expression and causes G1 arrest in normal and neoplastic T cells. Neckers LM, Bauer S, McGlennen RC, Trepel JB, Rao K, Greene WC. Transferrin receptor expression is essential for the proliferation of both normal and malignant T cells. While transferrin receptor expression in normal T cells is tightly coupled to interleukin-2 receptor expression, transferrin receptor expression in malignant cells is usually constitutive and is released from this constraint. Temporally, the appearance of these membrane receptors is preceded by changes in the expression of the proto-oncogenes c-myc and c-myb. In addition, although an increase in the level of intracellular free calcium occurs early in the sequence of T-cell activation, the activation events dependent on this calcium flux have not been resolved. In the present study we report that diltiazem, an ion channel-blocking agent that inhibits calcium influx, arrested the growth in vitro of both normal and malignant human T cells in the G1 phase of the cell cycle. However, diltiazem did not inhibit the expression of c-myc or interleukin-2 receptor mRNA and protein in normal mitogen-activated T cells or the constitutive expression of c-myc and c-myb mRNA in malignant T cells (T acute lymphoblastic leukemia cells). In contrast, diltiazem prevented the induction of transferrin receptor (mRNA and protein) in normal T cells and caused a progressive loss of transferrin receptor (mRNA and protein) in malignant T cells. These data demonstrate that diltiazem can dissociate several growth-related processes normally occurring in G1 and thereby disrupt the biochemical cascade leading to cell proliferation. PMID: 2432398 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 542: Cancer Res. 1986 Oct;46(10):5162-6. Expression of growth-regulated genes in human acute leukemias. Ferrari S, Narni F, Mars W, Kaczmarek L, Venturelli D, Anderson B, Calabretta B. We have investigated the expression of six growth-regulated genes (c-myc, c-myb, p53, 4F1, 2F1, and ornithine decarboxylase) and the S-phase-specific histone H3 gene in acute myeloid and lymphoid leukemic cells. We have purposely chosen three growth-regulated protooncogenes that share similar biological features and three gene sequences that have in common the cell cycle dependence of their expression in cells of different tissue and in different species. The level of expression was determined by measuring the amounts of specific RNA by Northern blot analysis. Levels of expression of the six growth-regulated genes were compared to the level of expression of the S-phase-specific H3 gene and among themselves. This method distinguishes the increased expression of a growth-regulated gene due to a true altered activation from over-expression which simply reflects an increase in the fraction of cycling cells. We have found that six of 14 patients with acute leukemias have markedly high ratios of c-myc/H3, c-myc/p53, and c-myc/c-myb expression. Two patients with altered c-myc expression have also a high ratio p53/H3. Within the group of cell cycle-dependent genes the ratios of expression seem in the overall much more regular with the clear exception of a patient with acute myelogenous leukemia in which the ratios 4F1/H3 and 2F1/H3 are significantly increased. A possible interpretation of these findings is that the fraction of noncycling leukemic cells that often constitute the majority of the entire leukemic population is in some cases in a true resting state, whereas in other cases heterogeneous degrees of growth arrest might occur. The altered expression of c-myc seems the feature most commonly associated with this putative growth arrest of leukemic cells suggesting that this gene may contribute to the impairment of proliferative control that is associated with the leukemic phenotype. PMID: 3756869 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 543: Cancer Res. 1986 Oct;46(10):5302-11. Enhanced expression of c-myc and decreased expression of c-fos protooncogenes in chemically and radiation-transformed C3H/10T1/2 Cl 8 mouse embryo cell lines. Shuin T, Billings PC, Lillehaug JR, Patierno SR, Roy-Burman P, Landolph JR. c-abl, c-fos, c-Ha-ras, c-myc, and c-mos were expressed whereas c-sis, c-fms, c-rel, c-src, and c-myb expression was not detectable in C3H/10T1/2 Cl 8 (10T1/2) cells and in eight chemically and radiation-transformed 10T1/2 cell lines. The expression of c-abl, c-fos, c-Ha-ras, and c-myc was growth-related in nontransformed 10T1/2 cells. c-abl and c-fos expression increased at confluence by 5- and 9-fold, respectively, compared to that in log phase cells. c-Ha-ras and c-myc transcripts were most abundant in log phase cells and decreased by 70 and 50%, respectively, in confluent cells. There were no significant growth-related changes in the expression of c-Ha-ras, c-myc, or c-abl in methylcholanthrene-transformed Cl 15 cells. The c-fos transcript was not detected in Cl 15 cell cultures. c-abl, c-fos, c-ras, and c-myc were expressed in whole C3H mouse embryo tissue, mouse liver, and 10T1/2 cells. Sizes of these protooncogene transcripts in 10T1/2 cells were the same as those in whole embryo tissue, except that 10T1/2 cells did not express the 8.2-kilobase abl transcript. At subconfluence, equivalent low levels of c-mos expression were observed in nontransformed and in the eight transformed 10T1/2 cell lines. The level of c-abl expression was similar in the nontransformed and in the eight transformed cell lines, but there was a new 8.2-kilobase transcript in the transformed MCA Cl 15 cell line. c-fos was expressed in 10T1/2 cells but was not detectable or greatly reduced in eight transformed cell lines. c-Ha-ras was expressed to a similar extent in eight transformed cell lines and in nontransformed 10T1/2 cells. In the UVC-4 transformed cell line, extra 3.3-kilobase Ha-ras and 7.5-kilobase Ki-ras transcripts were observed. c-myc was expressed at 4- to 7-fold higher levels in six transformed cell lines compared to 10T1/2 cells. There were no major rearrangements in or amplification of the c-myc gene in three transformed cells overexpressing this gene 5-fold. These studies show that enhanced expression of c-myc and decreased expression of c-fos correlate with the chemically and radiation transformed states of 10T1/2 cells. Changes in c-fos and c-myc oncogene expression may be casually linked to late stages of neoplastic transformation in these chemically and radiation transformed 10T1/2 cell lines. PMID: 2875790 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 544: Mol Biol (Mosk). 1986 Sep-Oct;20(5):1409-21. [Transcription of cellular oncogenes in human tumors] [Article in Russian] Spitkovskii DD, Zborovskaia IB, Kiselev FL. The analysis of 11 various oncogenes expression in different human tumors showed that each tumor is characterised by a specific functioning program of these genes. In 40-50% of tumors the oncogenes ras, fos and myc are expressed. All other oncogenes are either considered to be "silent" or are expressed only in few cases. The increased expression of sis and myb oncogenes is observed in metastases. PMID: 3773891 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 545: Proc Natl Acad Sci U S A. 1986 Sep;83(18):6849-53. Changes in gene expression associated with induced differentiation of erythroleukemia: protooncogenes, globin genes, and cell division. Ramsay RG, Ikeda K, Rifkind RA, Marks PA. Hexamethylenebisacetamide (HMBA)-induced differentiation of murine erythroleukemia cells (MELC) is a multistep process involving an early latent period during which a number of metabolic changes have been detected, but the cells are not yet committed irreversibly to differentiate. Commitment is defined as the capacity of MELC to go on to express the program of terminal cell division and gene expression (such as the accumulation of globin mRNA) upon removal of the HMBA from the culture. In the presence of HMBA, a small proportion of MELC are committed by 10-12 hr and greater than 90% by 48-60 hr. The present study shows that, during the initial 4 hr of culture, HMBA causes a marked decrease in c-myb and c-myc and an increase in c-fos mRNA levels. With continued culture, the decrease in c-myb and the increase in c-fos mRNA persists, while c-myc mRNA returns to control levels before the time that MELC begin to show irreversible differentiation. Dexamethasone, which blocks expression of HMBA-induced MELC differentiation, does not alter the early pattern of changes in protooncogene mRNA nor the sustained elevation of c-fos, but it does inhibit the continued suppression of c-myb allowing c-myb to return toward control levels. Hemin, which induces MELC to accumulate globins but does not initiate commitment to terminal cell division, does not alter these protooncogene mRNA levels. These studies suggest that, although the early decrease in c-myb and c-myc and increase in c-fos mRNAs may be involved in the multistep events leading to differentiation, the continued suppression of c-myb is critical for HMBA-induced MELC commitment to terminal cell division. PMID: 3462732 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 546: Lab Invest. 1986 Sep;55(3):269-75. Expression of monocyte-specific oncogenes c-fos and c-fms in HL60 cells treated with vitamin D3 analogs correlates with inhibition of DNA synthesis and reduced calmodulin concentration. Brelvi ZS, Christakos S, Studzinski GP. Monocytic differentiation of cultured leukemic cells HL60 can be induced by a variety of compounds including analogs of vitamin D3. We studied the expression of oncogenes c-fos, c-fms, c-fes, c-myb, c-myc, and c-Ha-ras during this process, and attempted to relate these and a conventional marker of monocytic differentiation, the nonspecific esterase activity, to changes in cytosol levels of the Ca2+-binding proteins. The analogs of vitamin D3, 1 alpha,25-dihydroxycholecalciferol, 1 alpha,25-dihydroxy-26,27-hexafluorocholecalciferol, and 1 alpha,25-dihydroxy-24R-fluorocholecalciferol, reduced the total calcium binding activity and the cellular levels of calmodulin, but calbindin D28k could not be detected in HL 60 cells. A correlation was evident between the potency of these compounds as inducers of differentiation demonstrated by nonspecific esterase activity, the degree of reduction in calmodulin concentration, the rate of the inhibition of DNA synthesis and of expression of c-myc and c-myb genes, and the induction of the expression of oncogenes c-fos and c-fms. These experiments indicate that the events which underlie monocytic differentiation of HL 60 cells can be observed to occur in discrete steps which include an inhibition of DNA synthesis, a reduction of cellular levels of calmodulin, and altered expression of several oncogenes. PMID: 3018359 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 547: Nature. 1986 Aug 21-27;322(6081):748-50. Expression of a transfected human c-myc oncogene inhibits differentiation of a mouse erythroleukaemia cell line. Dmitrovsky E, Kuehl WM, Hollis GF, Kirsch IR, Bender TP, Segal S. The Friend-virus-derived mouse erythroleukaemia (MEL) cell lines represent transformed early erythroid precursors that can be induced to differentiate into more mature erythroid cells by a variety of agents including dimethyl sulphoxide (DMSO). There is a latent period of 12 hours after inducer is added, when 80-90% of the cells become irreversibly committed to the differentiation programme, undergoing several rounds of cell division before permanently ceasing to replicate. After DMSO induction, a biphasic decline in steady-state levels of c-myc and c-myb messenger RNAs occurs. Following the initial decrease in c-myc mRNA expression, the subsequent increase occurs in, and is restricted to, the G1 phase of the cell cycle. We sought to determine whether the down-regulation is a necessary step in chemically induced differentiation. Experiments reported here indicate that expression in MEL cells of a transfected human c-myc gene inhibits the terminal differentiation process. PMID: 3528861 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 548: Br J Dermatol. 1986 Aug;115 Suppl 31:128-32. Onc-gene expression in hyperplasia induced by tape stripping or by topical application of TPA. Giacomoni PU. Guinea-pig ears were treated topically with 20 nmol of 12-O-tetradecanoyl phorbol-13-acetate, or deprived of their horny layer by nine successive strippings. At different times after the treatment, the animals were sacrificed, the epidermis removed from the ears, and the RNA from the epidermis purified and analysed by dot-blot hybridization in order to assess and determine the amount of RNA able to hybridize to each one of the 18 onc-gene DNA probes. The following probes were used: v-src, v-fps, v-yes, v-ros, v-myc, c-myc, v-erb AB, v-myb, v-mos, v-Ha-ras, v-Ki-ras, v-abl, v-fos, v-fes, v-fms, c-sis, B-lym, v-raf. At 0 h, expression of B-lym and of myc and fos is seen. ErbAB mRNA is detected between 10 min and 4 h after stripping, as well as after TPA application. B-lym mRNA is detected for up to 36 h after stripping and for up to 8 h after TPA application. C-myc mRNa is detected for up to 36 h after tape stripping, but only for the first hour after TPA application. RNA complementary to the other onc probes was not detected, and synthesis of RNA complementary to an actin DNA probe was observed for 8 h after TPA application. PMID: 2427103 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 549: Cancer Res. 1986 Aug;46(8):4097-103. Differential expression of protooncogenes related to transformation and cancer progression in rat myoblasts. Leibovitch SA, Leibovitch MP, Guillier M, Hillion J, Harel J. We previously derived, from a nonmalignant clonal line of rat myogenic cells (L6 alpha 1), two sublines which have lost the capacity to differentiate, the M4 cell of low malignancy and the RMS4 cell of high malignancy. In the present study it is shown that 14 of 15 protooncogenes analyzed exhibit detectable levels of transcripts during L6 alpha 1 cell proliferation. When L6 alpha 1 cells from myotubes, the levels of c-abl, c-myb, and c-Ha-ras transcripts remain unchanged, the level of c-N-ras RNA is augmented, the level of c-erbB RNA is markedly reduced, and all other c-onc transcripts (c-erbA, c-sis, c-src, c-fes, c-fms, c-fos, c-myc, c-Ki-ras, and the putative tyrosine kinase transcript of the c-fgr gene) become hardly, if at all, detectable. Surprisingly, when the three cell types are growing at similar rates only, one protooncogene (c-mos) is not expressed at detectable levels in L6 alpha 1, two others (c-fos, c-erbA) are not expressed in M4 or in RMS4, and three additional ones (c-erbB, c-sis, c-src) are expressed in M4 but not in RMS4. Moreover the level of c-fes RNAs is markedly lower in RMS4 than in M4 or L6 alpha 1. By contrast, the level of two c-Ki-ras 5.4- and 2.2-kilobase transcripts is lower in M4 and L6 alpha 1 than in RMS4, and the latter contains another abundant c-Ki-ras 3.8-kilobase transcript which is hardly detectable in M4 and not at all in L6 alpha 1. These data suggest an activation of the c-Ki-ras gene in the malignant myoblasts and some relationship between the progression of malignancy and inactivation of certain other c-onc genes. PMID: 2425941 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 550: J Virol. 1986 Jul;59(1):172-5. Dispersed chromosomal localization of the proto-oncogenes transduced into the genome of Mill Hill 2 or E26 leukemia virus. Symonds G, Quintrell N, Stubblefield E, Bishop JM. Both Mill Hill 2 and E26 retroviruses have transduced two cellular genes--c-myc and c-mil/mht (Mill Hill 2) and c-myb and c-ets (E26). We localized the genes transduced by these viruses to different chromosomes: c-myc and c-myb to relatively large chromosomes and c-mil/mht and c-ets to microchromosomes. Thus, like avian erythroblastosis virus, each of these retroviruses has transduced two cellular genes unlinked in the chicken genome. PMID: 3012116 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 551: Proc Natl Acad Sci U S A. 1986 Jun;83(12):4394-8. Expression of cellular oncogenes in primary cells from human acute leukemias. Mavilio F, Sposi NM, Petrini M, Bottero L, Marinucci M, De Rossi G, Amadori S, Mandelli F, Peschle C. The structure and the expression of 11 cellular oncogenes (protooncogenes) were analyzed in primary cells from 20 acute lymphocytic (ALL) and 31 acute myelogenous (AML) leukemia patients. Neoplastic cells, obtained prior to initiation of therapy, were purified and classified, on the basis of both surface antigen pattern and morphology, into pre-B, B, and T ALL and M1-M5 AML. RNA was extracted and analyzed for expression of cellular oncogenes coding for nuclear proteins (c-myc, c-myb, c-fos), the beta-chain of platelet-derived growth factor (c-sis), growth factor receptors or related proteins (c-src, c-abl, c-fes, c-erbB), or putative intermediate transducers of mitogenic signals (c-Ha-ras, c-Ki-ras, c-N-ras). Quantitative analysis of total RNA was carried out by dot blot hybridization to specific cDNA or genomic probes. Number and size of transcripts were evaluated by blot hybridization of electrophoretically fractionated poly(A)+ RNA. Expression of c-myc and c-myb was detected in all leukemic cells at variable levels and was characterized by well-defined patterns within ALL subtypes. Conversely, significant levels of c-fos transcripts were detected only in myelomonocytic (M4) and monocytic (M5) leukemias. Among the "src-family," c-fes was expressed more in AML than ALL, and c-abl was expressed at variable but not elevated levels in all leukemia types. c-Ha-ras was uniformly expressed at low levels, as in non-neoplastic cells. c-Ki-ras transcription was detected only in T ALL; N-ras expression was barely demonstrable. The structure of these protooncogenes was not grossly modified, as evaluated by Southern analysis, except for c-myc rearrangement in B ALL. These studies indicate that cellular oncogene expression in specific subtypes of leukemic cells may relate to either the proliferative activity (c-myc, c-myb) or the differentiation state (c-fos) of the cells, or possibly to expression of receptors for putative hemopoiesis-related growth factors (c-fes, c-abl). Our data provide a basis for in-depth analysis of protooncogene expression in normal and neoplastic hemopoiesis. PMID: 3520570 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 552: Proc Natl Acad Sci U S A. 1986 Jun;83(11):3982-6. Sequential expression of protooncogenes during lectin-stimulated mitogenesis of normal human lymphocytes. Reed JC, Alpers JD, Nowell PC, Hoover RG. The proliferation of non-neoplastic T lymphocytes is regulated, in part, by the coordinated expression of genes encoding T-cell growth factor (interleukin 2, IL2), IL2 receptors (IL2R), and transferrin receptors (TFR). In addition to growth factors and their receptors, protooncogenes may regulate lymphocyte proliferation. We used cloned cDNAs homologous to 21 different protooncogenes to screen for their expression at the mRNA level in human peripheral blood mononuclear cells (PBMC) stimulated with the mitogenic lectin phytohemagglutinin (PHA), and we compared the time course of accumulation of mRNAs for these protooncogenes to that of mRNAs for the IL2, IL2R, TFR, and histone H3 genes. mRNAs for c-abl, c-ets, c-yes, and N-ras were present in unstimulated PBMC. After stimulation of PBMC by PHA, we detected marked increases within 10 min in the levels of mRNA for c-fos and c-myc; within 6 hr for IL2 and IL2R mRNAs; within 14 hr for c-myb, p53, N-ras, and TFR mRNAs; and within 24-36 hr for H3 mRNA. Expression of c-abl, c-ets, and c-yes increased gradually following stimulation with PHA. None of the other protooncogenes tested was expressed in PBMC. Addition of the protein synthesis inhibitor cycloheximide, before the addition of PHA to cultures, abolished the PHA-induced accumulation of mRNAs for c-myb, N-ras, and TFR, but not of mRNAs for c-fos, c-myc, IL2, and IL2R. These data indicate that c-fos, c-myc, IL2, and IL2R belong to a group of genes expressed early, whereas c-myb, N-ras, and TFR belong to a group of genes expressed later in PHA-activated PBMC, and that the products of the c-fos and c-myc protooncogenes are not required for expression of IL2 or IL2R genes. Addition of purified IL2 augmented the expression of the later-expressed genes c-myb, p53, N-ras, and TFR in PHA-stimulated cultures of PBMC, as well as of the early genes c-myc and IL2R, but not of c-fos and IL2, thus suggesting that PHA and IL2 stimulate the expression of overlapping, but nonidentical, sets of genes in PBMC. PMID: 3012540 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 553: Blood. 1986 Jun;67(6):1698-704. Absence of oncogene amplifications and occasional activation of N-ras in lymphoblastic leukemia of childhood. Rodenhuis S, Bos JL, Slater RM, Behrendt H, van 't Veer M, Smets LA. To examine whether determination of (1) the copynumber or restriction pattern of certain oncogenes or (2) the mutational activation of the N-ras gene might contribute to the risk classification of acute lymphoblastic leukemia of childhood (ALL), we investigated DNA isolated from lymphoblasts of untreated patients. Restriction enzyme analysis of cellular oncogenes was performed on DNA of 25 patients. No rearrangements could be demonstrated within or near the genes c-myc, c-myb, c-abl, bcr, c-Ki-ras, and N-ras. No amplifications of these genes nor of N-myc or c-Ha-ras were present. Eight of 21 patients were heterozygote for "rare" Ha-ras allelic restriction fragments that have been associated with an increased risk of developing a malignancy. These patients were clinically indistinguishable from patients lacking these fragments. The breakpoint cluster region (bcr) that is rearranged in all patients with Philadelphia chromosome positive chronic myeloid leukemia, was normal in all cases, including at least one patient with Philadelphia chromosome positive ALL. A 2.8 kb HindIII fragment of a hitherto unknown gene or pseudogene related to v-myb probably derives from the Y chromosome. Nineteen patients were examined for point mutations in the N-ras gene, using a novel synthetic oligonucleotide hybridization assay. In two patients activating point mutations were present, both in positions 1 of the 12th codon. Both patients were somewhat older than the others (16 and 11 years), had L2 morphology, and were shown to have high growth fractions of tumor in their bone marrow. PMID: 3011151 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 554: Arthritis Rheum. 1986 Jun;29(6):755-60. Increased proto-oncogene expression in peripheral blood lymphocytes from patients with systemic lupus erythematosus and other autoimmune diseases. Boumpas DT, Tsokos GC, Mann DL, Eleftheriades EG, Harris CC, Mark GE. Using RNA hybridization techniques, we examined the expression of proto-oncogenes associated with lymphocyte activation in vitro in patients with systemic lupus erythematosus and other autoimmune diseases. T and B lymphocytes from these patients were found to have significantly increased expression of c-myc, c-myb, and c-raf RNA when compared with those of normal individuals. Among the mononuclear cell subpopulations, B lymphocytes expressed higher levels of RNA for these proto-oncogenes compared with the T lymphocytes. Since prompt expression of these and other proto-oncogenes occurs in fibroblasts and lymphocytes following mitogenic stimulation, we propose that the present findings reflect the pathologically activated state of various lymphocytic subpopulations which is observed in systemic lupus erythematosus and in other autoimmune diseases. Endogenous and exogenous factors which lead to the expression of autoimmunity might share the induction of proto-oncogene expression as a common pathogenetic step. PMID: 2424462 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 555: J Exp Med. 1986 May 1;163(5):1292-307. Oncogene expression in autoimmune and normal peripheral blood mononuclear cells. Klinman DM, Mushinski JF, Honda M, Ishigatsubo Y, Mountz JD, Raveche ES, Steinberg AD. PBMC from patients with autoimmune diseases and from normal controls were studied for the expression of several cellular oncogenes. Gene expression was assessed by Northern blot analysis of poly(A)+ RNA obtained from leukapheresis samples. Patients with SLE expressed significantly more c-myc protooncogene RNA than did normal controls. Increased expression of the N-ras protooncogene was found in that subset of patients whose autoimmune disease was very active. Cells from individuals with SLE, but not from those with other autoimmune illnesses, showed significantly decreased levels of the c-myb and c-fos protooncogenes. To examine the implications of these findings, B and T cells were purified from apheresis samples donated by normal volunteers. When mitogen was used to activate the B cells in vitro, their pattern of protooncogene expression changed to resemble that found in freshly isolated cells from lupus patients. These results suggest that the differences detected in the expression of protooncogenes by patients with SLE may be due to the abnormal activation of their B cells in vivo. The pattern of protooncogene expression found in patients with other autoimmune illnesses is consistent with the activation of additional cell types in those diseases. PMID: 3701256 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 556: Cancer Res. 1986 May;46(5):2482-7. Antigens expressed on NIH 3T3 cells following transformation with DNA from human pancreatic tumor. Hollingsworth MA, Rebellato LM, Moore JW, Finn OJ, Metzgar RS. This report documents that the pancreatic adenocarcinoma cell line, HPAF, contains oncogene activity detected by transformation of NIH 3T3 cells through transfection with HPAF DNA. The HPAF transfected NIH 3T3 cells do not contain oncogenes homologous with c-H-ras, c-K-ras, c-N-ras, v-fms, c-myb, c-sis, v-fgr, c-mos, c-myc, c-fos, v-fes, v-src, v-erb A, v-erb B, c-N-myc, v-raf, or v-abl, other than the endogenous mouse genes. The transfectants do express proteins detected by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis which were not found in nontransfected NIH 3T3 cells. Monoclonal antibodies raised against the transfectants recognize proteins not found in untransfected NIH 3T3 cells that are antigenically identical to proteins found in the HPAF cells. These antigens are also detected on six other human pancreatic adenocarcinoma cell lines but show a much more restricted distribution on lymphoblastoid, melanoma, prostatic carcinoma, and normal skin fibroblast cell lines. PMID: 3697988 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 557: Mol Cell Biol. 1986 May;6(5):1796-802. Coordinate regulation of myelomonocytic phenotype by v-myb and v-myc. Symonds G, Klempnauer KH, Snyder M, Moscovici G, Moscovici C, Bishop JM. Both avian myeloblastosis virus (by the action of v-myb) and avian myelocytomatosis virus MC29 (by the action of v-myc) transform cells of the myelomonocytic lineage. Whereas avian myeloblastosis virus elicits a relatively immature phenotype, cells transformed by MC29 resemble mature macrophages. When cells previously transformed by v-myb were superinfected with MC29, their phenotype was rapidly altered to that of a more mature cell. These superinfected cells expressed both v-myb (at a level similar to that found before superinfection) and v-myc. It therefore appears that the expression of v-myc can elicit certain properties of a more differentiated phenotype. In addition, unlike cells transformed by v-myb alone, the cells expressing both v-myb and v-myc could not be induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate to differentiate to fully mature macrophages. Cells with a morphology similar to that of the superinfected cells were elicited by simultaneously infecting yolk sac macrophages with avian myeloblastosis virus and MC29. Such cells expressed both v-myb and v-myc. These results indicate that expression of v-myb and v-myc in infected cells coordinately regulates myelomonocytic phenotype and that the two viral oncogenes vary in their ability to interfere with tumor promoter-induced differentiation. Our findings also sustain previous suggestions that the oncogenes v-myb and v-myc may not transform target cells by simply blocking differentiation. PMID: 3023905 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 558: Cancer Res. 1986 May;46(5):2457-62. Glucocorticoid inhibition of c-myc, c-myb, and c-Ki-ras expression in a mouse lymphoma cell line. Eastman-Reks SB, Vedeckis WV. Glucocorticoid hormone treatment of certain T-cell-derived lymphomas and leukemias and of immature thymocytes results in cell death. Furthermore, glucocorticoid-mediated killing of S49 mouse lymphoma cells appears to involve the control of the cell cycle; i.e., S49 cells treated with glucocorticoids are arrested in G1 of the cell cycle when events controlling cell proliferation occur. The protooncogenes, c-myc, c-myb, and c-Ki-ras may be involved in cell cycle regulation and proliferation state in both normal and neoplastic cells. We report here that the steady state mRNA levels of c-myc, c-myb, and c-Ki-ras in S49 cells are dramatically and rapidly decreased after glucocorticoid treatment. Minimal expression is observed after 9 h, remaining at a constant low level at 11 h. Flow cytometry reveals no significant alteration in the cell cycle distribution of S49 cells up to 12 h after treatment. These findings suggest that glucocorticoids suppress the expression of these protooncogenes and that this may be the mechanism whereby glucocorticoids inhibit cell cycle progression in T-lymphoid cell lines. PMID: 3008988 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 559: J Exp Med. 1986 Apr 1;163(4):922-37. Lymphokine and nonlymphokine mRNA levels in stimulated human T cells. Kinetics, mitogen requirements, and effects of cyclosporin A. Granelli-Piperno A, Andrus L, Steinman RM. Northern and dot blotting with a panel of DNA probes were used to monitor the levels of specific mRNAs in mitogen-stimulated human T cells. The induction of IL-2 and IFN mRNAs required the synergistic action of PMA and either PHA or OKT3 mAb. In contrast, several nonlymphokine genes, the protooncogenes c-fos and c-myc, and the IL-2-R gene, were induced by either PHA or PMA alone. PHA increased the background levels of a 70 kD heat shock protein mRNA, but did not affect the observed background of c-myb mRNA. For all mRNAs that were induced, isolated CD4 and CD8 T cell subsets behaved similarly. Exogenous IL-2 had little (IFN) or no (IL-2) effect on lymphokine mRNAs, but significantly increased c-myc, IL-2-R and heat shock protein mRNAs. Therefore, the stimuli for lymphokine mRNAs differed from those required for several inducible nonlymphokine genes. IL-2 and IFN mRNAs exhibited some important similarities with c-myc, however. The levels of IL-2, IFN, and c-myc mRNA followed similar kinetics, peaking at 3 h in restimulated blasts and at 12 h in unstimulated T cells. The subsequent downregulation of lymphokine and c-myc mRNAs was retarded by cycloheximide. The induction of IL-2, IFN, and c-myc mRNAs was blocked by the immunosuppressive drug CsA, but not by the inactive analog CsH, and this block occurred at the level of nuclear transcription. Since the exogenous stimuli for lymphokine and c-myc gene expression differ, we suggest that intracellular controls must be shared to account for the similarities in their kinetics of expression and CsA sensitivity. PMID: 2419474 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 560: Biochem Biophys Res Commun. 1986 Mar 28;135(3):1112-8. Sequential expression of proto-oncogenes during a mouse erythroleukemia cell differentiation. Todokoro K, Ikawa Y. To investigate the possible involvement of proto-oncogenes in the regulation of cell differentiation and proliferation, their transcriptional levels were measured by Northern blot analysis during the process of dimethyl sulfoxide-induced differentiation of mouse erythroleukemia cells. The differentiation into erythrocytes was accompanied by sequential transient expression of the proto-oncogenes in the order of c-fos, c-myb, c-myc and c-k-ras, during the first 48 hr of differentiation induction. Following the transient expression of these proto-oncogenes, adult type sss-globin and embryonic type yl-globin gene transcripts appeared and accumulated in terminally differentiated cells. The expression of ten other proto-oncogenes examined here were not detected, nor dramatically changed during differentiation process. PMID: 3457564 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 561: Br J Haematol. 1986 Feb;62(2):287-92. Cellular levels of mRNA from c-myc, c-myb and c-fes onc-genes in normal myeloid and erythroid precursors of human bone marrow: an in situ hybridization study. Emilia G, Donelli A, Ferrari S, Torelli U, Selleri L, Zucchini P, Moretti L, Venturelli D, Ceccherelli G, Torelli G. The expression of three onc-genes, c-myc, c-myb and c-fes, has been evaluated at the cellular level in myeloid and erythroid precursors of normal human bone marrow, by "in situ" hybridization with tritium-labelled probes. A relatively large amount of m-RNA from the three onc-genes was detected in myeloblasts and promyelocytes, but whereas the expression of c-myc and c-myb decreased in more advanced stage of maturation of the myeloid lineage, c-fes mRNA remained at a relatively high level until the granulocyte stage. c-myc and c-myb were expressed at a fairly high level in basophilic erythroblasts, which also showed low levels of c-fes mRNA. No expression of these onc-genes was detectable in more mature erythroblasts. Megakaryocytes showed high levels of m-RNA from all three onc-genes. Our results suggest that c-myc and c-myb expression is related in some way to the cellular proliferation of myeloid and erythroid precursors, whereas c-fes expression is more restricted to myeloid differentiation. PMID: 3947550 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 562: Science. 1986 Jan 17;231(4735):261-5. Alterations of myc, myb, and rasHa proto-oncogenes in cancers are frequent and show clinical correlation. Yokota J, Tsunetsugu-Yokota Y, Battifora H, Le Fevre C, Cline MJ. Alterations of c-myc, c-rasHa, or c-myb oncogenes were found in more than one-third of human solid tumors. Amplification of c-myc occurred in advanced, widespread tumors or in aggressive primary tumors. Apparent allelic deletions of c-rasHa and c-myb can be correlated with progression and metastasis of carcinomas and sarcomas. PMID: 3941898 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 563: Cancer Surv. 1986;5(2):309-27. Oncogenes with potential nuclear function: myc, myb and fos. Eisenman RN, Thompson CB. The protein products of the retroviral oncogenes, v-myc, v-myb and v-fos, and their normal cellular counterparts, the c-myc, c-myb and c-fos proto-oncogenes, have been found to be localized predominantly in the nucleus. In view of the oncogenicity of the retroviral forms of these genes, it is probable that they have central roles in the nuclear events involved in cellular proliferation and differentiation. To investigate these possibilities, detailed studies on the expression of these 'nuclear oncogenes' have been performed. The cellular forms of all three genes are normally expressed in a variety of cell types during proliferation and have RNA and protein products with short half-lives, which is consistent with the idea that they may have regulatory roles. Studies have shown that both c-myc and c-fos are induced during the stimulation of quiescent cells to enter the cell cycle and are continually expressed in replicating cells. In contrast, c-myb levels are greatest in cells as they prepare to enter and traverse S phase. Both c-myc and c-myb expression cease as cells terminally differentiate, whereas in some cell types c-fos is induced during differentiation. Unregulated expression of all three genes has distinct effects on cellular differentiation: myc seems to inhibit differentiation of several cell types when expressed at high levels; myb does not appear to effect differentiation in the systems in which it has been examined; and fos appears to be able to induce differentiation of some cell types. In most cell types, c-myc and c-myb expression is controlled primarily by posttranscriptional mechanisms, whereas c-fos expression is regulated primarily at the transcriptional level. The protein products of these oncogenes are all phosphorylated and probably undergo additional modifications. The nuclear association of these proteins is complex and apparently takes multiple forms. Taken together, these data suggest that all three nuclear oncogenes have distinct regulatory functions with respect to cellular proliferation and differentiation. Several models for function are discussed. PMID: 3779660 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 564: Leuk Res. 1986;10(10):1249-54. Differential patterns of expression of cell cycle-related genes in blast cells of acute myeloid leukemia. Torelli U, Selleri L, Venturelli D, Donelli A, Emilia G, Ceccherelli G, Turchi L, Torelli G. The expression of two G1-specific clones, p2A9 and p4F1, of two cell cycle-related oncogenes, c-myc and c-myb and of one S phase-specific gene, the H3 histone gene, was explored in 11 cases of acute myeloid leukemia. Both Northern blot analysis and in-situ hybridization were employed. Differential patterns of gene expression were observed. In 6 out of 11 cases a considerable or high expression of the p2A9 and p4F1 clones and of c-myc and c-myb oncogenes was observed. In 2 cases a high expression of c-myc was matched by low or absent expression of the other genes examined. In 3 cases the expression of 2A9, 4F1, c-myc and c-myb was very low or undetectable. In two of these cases a considerable expression of the H3 histone gene was observed. PMID: 3464813 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 565: J Cell Biochem. 1986;32(1):11-21. Regulated expression of the c-myb and c-myc oncogenes during erythroid differentiation. Kirsch IR, Bertness V, Silver J, Hollis GF. We have investigated the expression of the genes c-myb, c-myc, and alpha globin in murine erythroid cells at different stages of development, in viral-induced erythroleukemias, as well as in two mouse erythroleukemia cell lines that can be induced to terminally differentiate when exposed to dimethylsulfoxide. We find that there is a reciprocal correlation between the cell's production of messenger RNA for c-myb and globin. c-myc message shows a similar but less dramatic decrease coincident with globin RNA production. Initially with the administration of an inducing agent, dimethylsulfoxide, there is a rapid decrease of myc and myb mRNA, which is followed by signs of differentiation in the induced culture. We conclude that these oncogenes function in early maturational stages of development of these cells. In the erythroleukemic state these genes are down-regulated by forced differentiation and may play a direct role in influencing the state of differentiation of these cells. PMID: 3464612 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 566: Ann N Y Acad Sci. 1986;486:327-32. Oncogene expression in neurofibromatosis. Rowley PT, Kosciolek B, Bader JL. To investigate the role of oncogenes in malignancies characteristic of neurofibromatosis, oncogene transcripts were quantitated in a neurofibrosarcoma and in control tissue from a patient with hereditary neurofibromatosis. Sis and N-ras were moderately hyperexpressed, raf, Blym, and erbA were slightly hyperexpressed, and abl, erbB, fes/fps, fgr, fos, mos, myb, myc, N-myc, rasHarvey, rasKirsten, ros, src, and yes were not hyperexpressed in the tumor compared to the control tissue. Although additional tumors will be assayed before conclusions are possible, it may be significant that the two oncogenes most hyperexpressed are prior suspects for a pathogenetic role in tumors of the nervous system. PMID: 3105396 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 567: Adv Cancer Res. 1986;47:99-188. Oncogenes in retroviruses and cells: biochemistry and molecular genetics. Bister K, Jansen HW. Publication Types: Review PMID: 3022566 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 568: J Virol. 1986 Jan;57(1):371-5. Oncogene expression in reticuloendotheliosis virus-transformed lymphoid cell lines and avian tissues. Herzog NK, Bargmann WJ, Bose HR Jr. The genome of reticuloendotheliosis virus (REV-T) contains a unique oncogene, designated v-rel, which is inserted into the env region. Employing a cloned rel DNA probe, a single 2.9- to 3.0-kilobase v-rel mRNA was identified in poly(A)+ RNA from REV-T-transformed lymphoid cell lines. A 4.0-kilobase rel-specific transcript corresponding to the cellular homolog of the v-rel oncogene was identified in MSB-1 cells, a herpesvirus-transformed lymphoid cell line. Cytodot hybridization was used to quantitate the levels of rel, c-rel, c-myc, c-myb, c-abl, c-fms, c-Ha-ras, c-Ki-ras, c-src, c-yes, c-mos, and c-sis mRNA in REV-T-transformed cells. The levels of rel transcription in REV-T-transformed cells were elevated only two to eightfold over levels found in the transformed immature avian lymphoid cell line MSB-1. The relatively modest levels of rel transcription in REV-T-transformed cells and the significant differences between the lengths of the v-rel and c-rel mRNA suggest that REV-T transformation is the result of the production of an altered rel protein. The c-rel proto-oncogene is expressed in all avian hematopoietic tissues but is not expressed at significant levels in brain and muscle. The transcription of other proto-oncogenes is not enhanced in REV-T-transformed lymphoid cell lines. PMID: 2867231 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 569: J Cell Physiol. 1985 Dec;125(3):465-70. Density-dependent arrest of DNA replication is accompanied by decreased levels of c-myc mRNA in myogenic but not in differentiation-defective myoblasts. Sejersen T, Sumegi J, Ringertz NR. Myoblasts from primary rat cultures and established mouse (Cl10) and rat (L6, Ama 420) cell lines were examined for c-oncogene expression during exponential growth and under conditions which allowed myogenic differentiation. The abundance of c-Ki-ras transcripts in mRNA from confluent, quiescent cultures was reduced to 15-40% of that in mRNA from exponentially growing cells. This reduction was found both in primary myoblast cultures, myoblast lines that formed myotubes (L6 and Cl10) and in a differentiation defective subline (Ama 420). The level of c-myc transcripts was lowered when myogenic rat L6 myoblasts reached a high cell density, stopped DNA synthesis and formed myotubes. At the same cell density, growth arrested myoblasts of differentiation defective Ama 420 cells maintained a high level of c-myc expression. This shows that DNA replication and c-myc expression are independently regulated. All myoblast lines also showed expression of c-abl during exponential growth phase. Reduced expression was seen in differentiated L6 and Cl10 cultures. No expression was detected when mRNA from multiplying and differentiating myoblasts cultures were probed for c-myb, c-erbA, c-erbB, c-mos, c-fes, and c-src. The observations are consistent with a role for c-Ki-ras in myoblast proliferation and suggest that a reduction in c-myc expression may be a necessary prerequisite for terminal myogenic differentiation. PMID: 4066768 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 570: Lancet. 1985 Nov 9;2(8463):1035-9. Acute myelogenous leukaemia with c-myc amplification and double minute chromosomes. Alitalo K, Saksela K, Winqvist R, Alitalo R, Keski-Oja J, Laiho M, Ilvonen M, Knuutila S, de la Chapelle A. Cytogenetic analysis of bone-marrow cells from a woman with preleukaemia showed numerous mitoses with trisomy 4 and double minute chromosomes. These abnormalities were later seen in blood cells during subsequent acute myeloid leukaemia (AML). Complete remission was achieved with three courses of doxorubicin, cytosine arabinoside, and prednisone. A further clonal abnormality, trisomy 6, was seen in leukaemic cells after the first relapse. Analyses of total DNA from the peripheral-blood cells during relapse showed that the c-myc oncogene was amplified about 30-fold in the leukaemic cells. The N-myc, c-mos, and c-myb oncogenes showed only single-copy signals. On average about two copies of c-myc resided on each dmin chromosome. The finding of amplification of a cellular oncogene (c-myc) in fresh AML cells containing double minute chromosomes suggests that clonal evolution of some leukaemia cell populations may involve selection for increased dosage of oncogenes. Publication Types: Case Reports PMID: 2865517 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 571: Cell. 1985 Nov;43(1):253-61. Studies on the interaction of the human c-myc protein with cell nuclei: p62c-myc as a member of a discrete subset of nuclear proteins. Evan GI, Hancock DC. We have analyzed the localization of the human c-myc product (p62c-myc) at steady state in cells by immunoprecipitation and immunoblotting. We show that p62c-myc is extracted from nuclei by mild salt concentrations (below 200 mM), without affecting gross nuclear structure or causing extraction of major chromatin components. We observe no association between p62c-myc and the nuclear matrix. We also demonstrate that p62c-myc is a member of a discrete subset of nuclear proteins that are all rendered irreversibly insoluble in situ by exposure of isolated nuclei to physiological temperatures (37 degrees C). p62c-myc is sequestered into a similar insoluble complex in cells that have been subjected to heat shock. Finally, we show that avian v-myc and v-myb proteins in isolated nuclei also become insoluble after exposure to temperatures above 37 degrees C. We discuss the possible implications of these results. PMID: 3907852 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 572: Biochem Biophys Res Commun. 1985 Oct 30;132(2):548-54. Expression of cellular oncogenes in human prostatic carcinoma cell lines. Rijnders AW, van der Korput JA, van Steenbrugge GJ, Romijn JC, Trapman J. Prostatic cancer is one of the most frequent forms of malignancy in Western countries. Initially, growth of the majority of prostate tumors can be manipulated by endocrine therapy. However, ultimately androgen independent tumors continue to grow. We studied the expression of oncogenes in four different human prostatic carcinoma cell lines: PC 3, PC 133, PC 135, which are androgen independent, and the hormone dependent PC 82 cell line. Large amounts of Ha-ras and myc mRNA were present in all cell lines. Transcripts of fes, int-1 and abl were never detected. In some of the cell lines the presence of N-ras, Ki-ras, myb, fos, fms and sis mRNA was observed. The PC 82 cell line showed, in addition to myc and Ha-ras high levels of fos expression. Inhibition of tumor cell proliferation by withdrawal of androgen was accompanied by a tenfold reduction of the fos mRNA level and a twofold reduction of Ha-ras transcripts. In contrast, the expression of myc was not changed. PMID: 3904752 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 573: Mol Cell Biol. 1985 Oct;5(10):2874-7. Activation of c-myb expression by phytohemagglutinin stimulation in normal human T lymphocytes. Torelli G, Selleri L, Donelli A, Ferrari S, Emilia G, Venturelli D, Moretti L, Torelli U. The expression of c-myb in normal human T lymphocytes directly derived from a normal subject and not adapted to continuous growth in culture was found to be markedly increased after phytohemagglutinin stimulation. In the same cells, the expression of c-myc mRNA is a much earlier event compared with the appearance of c-myb mRNA, which takes place soon after that of histone H3 mRNA. The increase in c-myb expression was not due to a particular T-lymphocyte subset, as shown by in situ hybridization assays. PMID: 3915538 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 574: Cancer Res. 1985 Sep;45(9 Suppl):4568s-4573s. Production of oncogene-specific proteins and human T-cell leukemia (lymphotropic) retrovirus (HTLV-I) envelope protein in bacteria and its potential for use in human cancers and seroepidemiological surveys. Papas TS, Samuel KP, Kan NC, Ascione R, Wong-Staal F, Lautenberger JA. The oncogenes coding for the Harvey murine sarcoma virus p21ras protein as well as those coding for myc, myb, and mht products were fused to the amino-terminal portion of the bacteriophage lambda cII gene on the expression vector pJL6. In addition two regions of the gene for the human T-cell leukemia virus subgroup I (HTLV-I) envelope were expressed in our bacterial system. Each of 11 human sera tested that had been shown to contain antibodies to HTLV-I or -II by an enzyme-linked immunosorbent assay recognized the bacterially synthesized envelope proteins. No reaction was detected when 17 control sera were tested. This system will be useful for large-scale seroepidemiological surveys for HTLV-I and related human retroviruses. The other oncogene products expressed in our bacterial vector system also demonstrated specific immunoreactivities. In addition to this feature the bacterial ras protein was seen to bind guanosine diphosphate and was capable of autophosphorylation. Taken together these data suggest that the proteins produced with high efficiency by the bacterial expression system can be immunologically recognized as antigens and can in part perform some of their associated biochemical functions. PMID: 2861893 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 575: Exp Cell Res. 1985 Sep;160(1):19-30. Expression of cellular oncogenes in teratoma-derived cell lines. Sejersen T, Sumegi J, Ringertz NR. The expression of ten proto-oncogenes was studied in cell lines derived from transplantable mouse teratomas. The cell lines represent different forms of early embryonic cell specialization. The analysis included two embryonal carcinoma (EC) lines (PCC3 and F9), and four differentiated cell lines derived from teratocarcinoma, namely trophoblastoma (3-TDM), parietal endoderm (PYS-2), visceral endoderm (PSA5-E) and skeletal myoblasts (Cl10). The expression of c-oncogenes was studied by analysing poly(A)+RNA for complementary sequences by dot blot and Northern blot hybridization. The results were related to the rate of cell multiplication and the state of differentiation by examining [3H]thymidine incorporation, growth curves and tissue-specific differentiation markers. Expression of c-myc and c-Ki-ras was found in all cell lines. In dot blot assays, poly(A)+RNA from all cell lines also hybridized with v-abl and v-sis probes. A marked decrease in c-myc expression was found in teratoma-derived myoblasts differentiating into myotubes. A similar reduction was found when 'nullipotent' F9 cells were induced by retinoic acid (RA) to form primitive endoderm. However, reduction of the growth rates of the parietal and visceral endodermal cell lines were not accompanied by decreased expression of c-myc or c-Ki-ras. Hybridization signals obtained with a v-sis probe was low in all teratoma-derived cell lines tested, except for the myogenic cell line Cl10. Both in exponentially growing and differentiated cultures of this line, two size classes of transcripts hybridized strongly to the v-sis probe. However, these transcripts, 7 and 3 kb, most likely represent endogenous retroviral transcripts and not c-sis transcripts. Expression of c-myb, c-mos, c-fes, c-src and c-erb A and c-erb B could not be detected in any of the cell lines studied. PMID: 2412863 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 576: Virology. 1985 Aug;145(1):154-64. Avian retrovirus S13: properties of the genome and of the transformation-specific protein. Benedict SH, Maki Y, Vogt PK. The avian retrovirus S13 codes for an env-linked transformation-specific glycoprotein with a molecular weight of 155,000 (gp155). Treatment of gp155 with endoglycosidase H or growth of S13-infected cells in the presence of tunicamycin reduces the molecular weight of gp155 to about 140K, but these gp155-related molecules may still contain sugar residues. The gp155 protein is not incorporated into virions; it is phosphorylated, but in immunoprecipitates does not show protein kinase activity. The genome of S13 is an 8.5-kilobase (kb) RNA; the helper virus genome is 7.5 kb in size. The putative onc sequences of S13 do not hybridize to DNA probes representing src, erb A, erb B, myc, myb, fps, fms, H-ras, B-lym, abl, rel, and ets. PMID: 2990097 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 577: Virology. 1985 Jul 15;144(1):115-26. Oncogene expression in murine splenic T cells and in murine T-cell neoplasms. Mally MI, Vogt M, Swift SE, Haas M. The differential expression of a series of proto-oncogenes has been examined in a group of cultured murine T-cell lymphomas that were induced following virus inoculation into, or X irradiation of, C57BL/6 mice. Two classes of T lymphoma cell lines were studied: growth factor-dependent (autocrine) cells, and growth factor-independent T lymphoma cells. Cell lines that were established from X-irradiation-induced T lymphomas were growth factor dependent, whereas T lymphoma lines grown from virus-induced tumors were generally growth factor independent. Of 18 cellular proto-oncogenes studied, five (c-myc, c-myb, c-abl, c-rasHa, c-rasKi) were consistently expressed in all cell lines tested. Thirteen other proto-oncogenes (c-mos, c-sis, c-rel, c-yes, c-fes3, c-fes4, c-fos, c-fms, c-src, c-erbA, c-erbB, int-1, Pim-1) were not expressed in any of the T lymphoma cells tested. Concanavalin A-stimulated spleen cells, representative of replicating T cells, expressed c-myc, c-abl, and Pim-1, suggesting that the products of these proto-oncogenes are involved in T-cell proliferation. The results indicate no qualitative differences (albeit some quantitative differences) in proto-oncogene expression between the growth factor-dependent and growth factor-independent cells. This suggests that expression of the five proto-oncogenes is in itself not sufficient to induce the progression of the growth factor-dependent cells to their fully growth factor-independent counterparts. Changes in the regulation of one or more of the five active proto-oncogenes, i.e., from an inducible to a constitutive state, and/or additional changes in the expression of other cellular genes may be required to induce the transformation of neoplastic T cells from growth factor dependence to growth factor independence. PMID: 2414915 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 578: Jpn J Cancer Res. 1985 Jul;76(7):551-4. c-myc Gene amplification in primary stomach cancer. Koda T, Matsushima S, Sasaki A, Danjo Y, Kakinuma M. Fourteen human primary stomach cancer tissues were screened by Southern blot hybridization using six oncogene probes (myc, myb, H-ras, K-ras, abl, mos), and an amplification of c-myc oncogene was found in one tissue. This is the first report of c-onc amplification in primary stomach cancer tissue. PMID: 2993214 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 579: Virology. 1985 Jun;143(2):680-3. Isolation of three new avian sarcoma viruses: ASV 9, ASV 17, and ASV 25. Cavalieri F, Ruscio T, Tinoco R, Benedict S, Davis C, Vogt PK. The newly isolated avian sarcoma viruses, ASV 9, 17, and 25, cause fibrosarcomas in young chickens and induce foci of transformed cells in chick embryo fibroblast cultures. They are defective in replication and belong to envelope subgroup A. The sizes of their genomes are 6 kb (ASV 9), 5 kb (ASV 17), and 6 kb (ASV 25), respectively. All three contain long terminal repeat (LTR) and gag sequences but lack pol. env is absent from ASV 9 and ASV 25, but some env sequences are detectable in ASV 17. None of the defective viral genomes hybridized to selected onc probes representing src, fps, yes, myc, myb, and erb A. erb B appears absent from ASV 9 and ASV 17, but some hybridization between the erb B probe and the RNA of ASV 25 was detected. ASV 9 codes for a transformation-specific gag-linked protein of 130kDa. Multiple gag-linked transformation-specific proteins are seen in ASV 17 and 25; they require further study. PMID: 2998035 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 580: Clin Exp Metastasis. 1985 Apr-Jun;3(2):77-86. Expression of abl and other oncogenes is independent of metastatic potential in Abelson virus-transformed malignant murine large cell lymphoma. Rotter V, Wolf D, Blick M, Nicolson GL. The role of oncogene expression in tumor metastasis was examined using the Abelson leukemia virus-transformed murine large cell lymphoma RAW117. Cell sublines of low and high metastatic potential expressed equally abl oncogene-coded mRNA and its phosphoprotein product p160, and the capacity of p160 to become autophosphorylated with gamma-[32P]ATP was the same among low and high metastatic cells. The expression of other oncogene-coded mRNAs (fos, myc, myb), if present, was also similar in low and high metastatic RAW117 cells. Although oncogene expression is thought to be important in initiating, and in some cases maintaining, the transformed phenotype, its expression in RAW117 lymphoma cells appears to be unrelated to metastatic phenotype. PMID: 4042463 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 581: DNA. 1985 Apr;4(2):171-82. Nucleic acid sequence database VI: Retroviral oncogenes and cellular proto-oncogenes. Chen HR, Barker WC. The databases of the Protein Identification Resource at the National Biomedical Research Foundation (NBRF) contain nucleic acid and protein sequences from 18 retroviral oncogenes (v-onc) and 8 cellular proto-oncogenes (c-onc). Comparison of the sequences between the v-onc and c-onc genes reveals: (i) The c-src, c-abl, c-mos, c-fos, c-ras, c-myb, c-myc, and c-sis genes contain coding regions that are highly conserved in the respective v-onc genes with a small number of base changes. (ii) There are more transitions than transversions. (iii) Some of these base changes are silent mutations and others generate amino acid substitutions in the viral proteins. The causes of these base changes in the coding sequences and the significance to oncogenic transformation of the amino acid substitutions in the viral proteins remain to be determined. Publication Types: Review PMID: 3888572 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 582: Cancer Res. 1985 Apr;45(4):1823-7. Amplification of the c-myc oncogene in a subpopulation of human small cell lung cancer. Saksela K, Bergh J, Lehto VP, Nilsson K, Alitalo K. We have examined a panel of human lung cancer cell lines for amplification and expression of the c-myc, N-myc, and c-myb oncogenes. The cell lines analyzed represent various histopathological types of lung cancer: small cell carcinoma with neuroendocrine properties; squamous cell carcinoma with epithelial markers; and large cell carcinoma with a mixed neuroendocrine-epithelial phenotype. Two of six cell lines, both of which were small cell carcinomas, showed about a 20-fold amplification of the c-myc oncogene. In both cell lines, the amplification is accompanied by an enhanced expression of c-myc. The N-myc or c-myb genes were not amplified in any of the cell lines, nor were they expressed in detectable amounts. The results confirm and extend earlier findings on c-myc amplification in small cell lung cancer. PMID: 2983887 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 583: Vopr Onkol. 1985;31(12):44-9. [Cell oncogene expression in human stomach tumors] [Article in Russian] Spitkovskii DD, Zborovskaia IB. The paper is concerned with the analysis of expression of myc, myb, fos, ras and sis oncogenes in 11 gastric tumors of different histological patterns, 5 histologically-unaltered areas adjacent to tumor and in stomach tumor metastases into lymph nodes. A high frequency of myc, ras and fos oncogene expression was registered in all the types of tissue examined without any apparent signs of tissue specificity. The study failed to detect sis oncogene transcripts. The myb oncogene, generally dormant in solid tumors, was expressed in 2 gastric tumor metastases. PMID: 4082507 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 584: J Mol Cell Immunol. 1985;2(3):121-31. Oncogene expression in autoimmune mice. Mountz JD, Mushinski JF, Mark GE, Steinberg AD. Cellular Immunology Section, National Institute of Arthritis, Diabetes, Digestive and Kidney Diseases, Bethesda, MD 20205. Systemic autoimmune disease states are known to be associated with abnormal cell growth or differentiation. In the murine models of systemic lupus erythematosus (SLE), specific genotypes result in dysregulated growth of certain lymphocyte subpopulations. Although genes underlying autoimmune syndromes have been characterized by mendelian genetics, it has not yet been possible to characterize them at the molecular level. Recently, it has become clear that cellular proto-oncogenes can regulate cell growth and differentiation. Therefore, we have studied the expression of five different proto-oncogenes; myc, myb, abl, bas, and raf, in organs and cells of various autoimmune strains. These genes were selected because each has previously been associated with abnormal hemopoietic cell growth, and because each has been at least partially characterized at the molecular and functional level. We have found selective abnormal proto-oncogene expression associated with the characteristic abnormal cell growth or differentiation of lymphocytes of autoimmune mice. The lymph nodes of MRL-lpr/lpr mice are packed with unusual T cells. These had a marked increase in myb expression. There was a 20-40-fold increase in myb RNA in lymph nodes of lpr/lpr mice on several different genetic backgrounds. The gld/gld mouse has a very similar unusual T cell in the lymph nodes: it also had a comparable increase in myb RNA in the nodes. In contrast, myb expression was not elevated in the other autoimmune mouse strains lacking these abnormal T cells. Whereas such lpr/lpr mice had increased myb expression in the lymph nodes and splenic T cells, they had markedly subnormal myb expression in the thymus, an organ with high myb in normal and in the other autoimmune strains. These results suggest that one phase of intrathymic differentiation in other mice occurs in the periphery of lpr/lpr mice. The spleens of NZB and male BXSB mice had increased myc expression which was found to be associated with B cells upon cell separation. Similarly, increased bas and abl expression was associated with autoimmune B cells. The xid gene, which retards or prevents the expression of murine lupus by retarding B cell maturation, was associated in BXSB.xid, NZB.xid, and MRL-lpr/lpr.xid congenic mice with marked reduction in expression of myc, bas, and abl in the spleens containing B cells, but not of myb in the lpr/lpr.xid nodes containing primarily the unusual T cells. Raf expression was found to be associated in lpr/lpr and gld/gld mice with both the unusual T cells and splenic B cells.(ABSTRACT TRUNCATED AT 400 WORDS) PMID: 3916923 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 585: Kroc Found Ser. 1985;19:301-8. Cellular and molecular studies on ataxia-telangiectasia lymphoblastoid cell lines. Fiorilli M, Crescenzi M, Carbonari M, Russo G, Businco L, Aiuti F. We have examined several AT-related lesions in lymphoblastoid cell lines (LCLs) derived from AT patients. Diminished sensitivity to gamma-irradiation was found in six of seven AT-LCLs. A seventh line, from a patient with apparently normal T-cell immunity, responded normally following radiation. Constitutive proteins from exponentially growing AT-LCLs were assessed by SDS-PAGE analysis and did not differ significantly from normals. IgM synthesis was also normal except for one AT-LCL that contained native IgM molecules of different sizes, corresponding to the presence of pentamers and oligomers. Analysis under reducing conditions showed normal-sized secretory mu-chains. Finally, we examined mRNAs corresponding to two oncogenes, c-myc and c-myb, in AT and normal LCLs and found marked overproduction of c-myc in one AT-LCL (ie,, ATL6). The latter findings suggest that AT cells might be prone to aberrantly express cellular oncogenes as a result of chromosomal instability and consequent transposition of oncogenes. PMID: 3877787 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 586: Leuk Res. 1985;9(7):833-42. Study of the levels of expression of two oncogenes, c-myc and c-myb, in acute and chronic leukemias of both lymphoid and myeloid lineage. Ferrari S, Torelli U, Selleri L, Donelli A, Venturelli D, Narni F, Moretti L, Torelli G. Total cellular RNA from a series of leukemic cell populations, both myeloid and lymphoid, as well as from normal circulating lymphocytes was analysed for the expression of two cellular oncogenes, c-myc and c-myb, by Northern blot hybridization assay. Expression of c-myc but not of c-myb was observed in unstimulated normal lymphocytes. Stimulation by PHA was shown to activate the expression of both genes. Remarkably different levels of expression of c-myc were observed in ALL, whereas in CLL the expression of c-myc was uniformly low or absent. Differential expression of c-myc was detected in AML as well as in CML, c-myb was differentially expressed in AML and ALL, and absent in CLL and CML. Other single cases of hemopoietic disorders were studied, but the expression of the two oncogenes was low or absent. Neither evident genome amplification nor genome rearrangements were detected in the cell DNAs digested with restriction endonucleases. PMID: 3860696 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 587: Proc Natl Acad Sci U S A. 1985 Jan;82(2):565-9. Comparison of chemically induced and spontaneous murine thymic lymphomas in RF and AKR mice: differential expression of c-myc and c-myb. Chinsky J, Lilly F, Childs G. Expression of 11 cellular oncogenes was determined in normal vs. lymphomatous thymic tissues of RF and AKR mice; only c-myc and c-myb transcripts were detected in an age-inappropriate pattern in thymomas. Normal thymocytes from young RF mice contained RNA transcripts of both genes, but the transcripts were no longer detected at 9 or more weeks of age. More than 90% of RF thymomas, occurring at 20-28 weeks of age after skin painting with 3-methylcholanthrene at 12 weeks, contained c-myc transcripts, and 70% of the tumors contained c-myb transcripts. Seven cell lines derived from these 3-methylcholanthrene thymomas expressed both cellular genes, as did 2 rare spontaneous thymomas of 12-month-old RF mice. No indication of rearrangement or amplification of either gene was seen in any of the RF tumors or cell lines. In AKR mice, transcripts of the 2 genes persisted longer in the normal thymus than in RF mice, but they were no longer detected at 26 weeks of age. Of 3 thymomas in 6-month-old 3-methylcholanthrene-treated AKR mice, all expressed c-myb and 2 expressed c-myc. Among 11 spontaneous AKR thymomas, however, only 2 showed detectable levels of both genes, and 2 more expressed c-myc or c-myb but not both. PMID: 3855567 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 588: Cancer Res. 1985 Jan;45(1):272-5. Expression of the c-myb oncogene in human small cell lung carcinoma. Griffin CA, Baylin SB. We have found that the oncogene c-myb is differentially expressed in human lung cancer cell lines and that myb-homologous RNA can be detected only in small cell lung cancer (SCLC) cell lines. Polyadenylic acid-RNA from 13 established cell lines was examined by Northern blotting for its ability to hybridize to a radiolabeled v-myb probe. A 3.5-kilobase RNA transcript homologous to v-myb is present in four of four lines of classic SCLC and in three of four SCLC variant lines but not in five of five non-small cell lung cancer lines tested. This transcript is the same size as that found in the immature myeloid cell lines KG1, but the amount of RNA is only about 10% of that in the KG1 line. A second transcript hybridizing to v-myb, 2.4 kilobases in size, is also present in the variant SCLC lines and the COLO 320 line, all of which have amplification of the c-myc gene and markedly increased c-myc messenger RNA. The presence of myb transcripts in SCLC suggests that the myb gene may have a specific role in the initiation or maintenance of an important human epithelial tumor. PMID: 2578097 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 589: Blood. 1984 Dec;64(6):1234-9. Oncogene expression in human leukemia. Blick M, Westin E, Gutterman J, Wong-Staal F, Gallo R, McCredie K, Keating M, Murphy E. The transforming genes of retroviruses (v-onc) are derived from normal cellular genes referred to as proto-oncogenes. These cellular genes have the capacity for conversion to oncogenes (c-onc) that are capable of inducing or maintaining the transformed state when they are overly expressed or altered by mutation or rearrangement. To study the possible involvement of these genes in human leukemia, we have analyzed their expression in a variety of fresh samples. We found that a number of oncogenes are expressed in different leukemic types and that although the transcript size did not vary for each gene, the copy number did. The myc gene (2.4 kb transcript) and the rasHa gene (1.5 kb transcript) were universally expressed. But in contrast to rasHa, the myc signal intensity varied. Myb (4.5 kb transcript) was expressed in all samples except B cell diseases. We detected low levels of abl expression (multiple mRNA species) in all leukemic types analyzed. Sis gene (4.2 kb transcript) expression was restricted to one patient sample with chronic myelogenous leukemia in blast transformation. PMID: 6208953 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 590: Cell. 1984 Dec;39(3 Pt 2):439-45. Autocrine growth induced by src-related oncogenes in transformed chicken myeloid cells. Adkins B, Leutz A, Graf T. Chicken myeloid cells transformed by the v-myb-or v-myc-containing leukemia viruses, E26 and OK 10, respectively, require chicken myelomonocytic growth factor (cMGF) for proliferation in vitro. Upon superinfection with retroviruses carrying oncogenes of the src gene family, these myeloid cells acquire the ability to grow in the absence of exogenous cMGF. Conditioned medium prepared from superinfected E26 cells contains a growth-stimulating activity similar in biological and immunological properties to cMGF. This activity is reduced by more than 80% following absorption of conditioned media with antiserum against cMGF. Incubation of superinfected E26 cells with an immunoglobulin fraction of antiserum against cMGF inhibits their proliferation, indicating that the cells are dependent on the secreted factor. We conclude that viral oncogenes of the src family can induce chicken myeloid cells to produce a cMGF-like factor(s) that stimulates proliferation of these cells in an autocrine fashion. PMID: 6096003 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 591: Exp Cell Res. 1984 Dec;155(2):496-506. Increased transcription of the c-myc oncogene in two methylcholanthrene-induced quail fibroblastic cell lines. Saule S, Martin P, Gegonne A, Begue A, Lagrou C, Stehelin D. The expression of three c-onc genes (c-erb, c-myc, c-myb) was investigated in five cell lines established from fibrosarcomas induced with 20-methylcholanthrene (MCA) of Japanese quails. These cell lines showed low levels of the three c-onc genes, with the exception of two cell lines that accumulated moderate (MCAQ 1-4) and large amounts (MCAQ3-5) of c-myc RNA. Molecular cloning and restriction endonuclease analyses indicated that expression of c-myc in these two cell lines were not associated with detectable rearrangements in the c-myc locus, that the size of the c-myc transcript (2.7 kb) in MCAQ 3-5 was similar to that of the normal c-myc messenger RNAs (mRNA) and that the transcriptional activation observed in MCAQ 3-5 was not mediated by the LTR (long terminal repeat) of a proximate ALV (avian leukosis virus) provirus. Finally, when analysed with the restriction enzymes Msp I and Hpa II, the c-myc locus of MCAQ 3-5 and MCAQ 1-4 was found hypomethylated as compared with that of the other cell lines tested that show low levels of c-myc transcripts. Our results suggest that one of the ways methylcholantrene could mediate transformation is by inducing an abnormal regulation of the c-myc gene. PMID: 6094223 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 592: EMBO J. 1984 Aug;3(8):1887-90. Differential expression of c-fos in hematopoietic cells: correlation with differentiation of monomyelocytic cells in vitro. Muller R, Muller D, Guilbert L. Among various neonatal mouse tissues, elevated levels of c-fos transcripts have been detected in crude preparations of bone. Here, we show that c-fos expression originates in the bone marrow, and to a lesser extent in adherent cells (macrophages). High levels of c-fos expression were also detected in primary cultures of differentiated bone marrow-derived macrophages, but not in cell lines resembling immature hematopoietic cells. However, when the human promyelocytic cell line HL60 was induced in vitro to differentiate into macrophages, c-fos expression was readily detectable. These findings suggest that c-fos expression in mononuclear phagocytic cells is restricted to late stages of differentiation. This pattern of c-fos expression is in marked contrast to those of the c-myb and c-myc genes which are transcriptionally active predominantly in precursor cells. In the amnion, where c-fos expression increases to high levels at late stages of gestation, synthesis of c-fos protein occurs in cells that do not resemble macrophages. It thus appears that c-fos expression in several distinct cell types is correlated with differentiation processes. PMID: 6479151 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 593: Nature. 1984 Jul 19-25;310(5974):249-51. Expression of myb, myc and fos proto-oncogenes during the differentiation of a murine myeloid leukaemia. Gonda TJ, Metcalf D. It is widely thought that c-onc genes (or proto-oncogenes)--the cellular progenitors of retroviral transforming genes--are involved in cellular differentiation and/or proliferation. Such ideas originate primarily from the ability of v-onc genes and 'activated' c-onc genes to induce uncontrolled cellular proliferation, and their capacity to arrest or interfere with differentiation processes in some systems. Haematopoietic cell populations provide additional support for these ideas as c-myb RNA is present in cell lines corresponding to immature, but not mature, cell types, and elevated levels have been found in tissues that are active in haematopoiesis. We have now examined the effects of induced differentiation on c-onc gene expression in a murine myeloid leukaemia cell line, WEHI-3B ('D+' subline). Our results show that the expression of c-myb and c-myc, at the level of transcription, decreases only at late stages in the monocytic differentiation of WEHI-3B cells, while expression of c-fos increases markedly. We suggest that c-myb and c-myc do not themselves control myeloid differentiation, but that they function in the maintenance of the proliferative state of myeloid cells. The induction of c-fos may reflect its role in some macrophage-specific functions. PMID: 6205276 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 594: Science. 1984 Jun 8;224(4653):1117-21. Amplification of the c-myb oncogene in a case of human acute myelogenous leukemia. Pelicci PG, Lanfrancone L, Brathwaite MD, Wolman SR, Dalla-Favera R. Amplification is one of the mechanisms by which cellular oncogenes may be altered in their function, possibly leading to neoplastic transformation. The oncogenes c-myc, c- abl , and c-Ki-ras are amplified in several different human neoplasias. The oncogene c-myb, which is specifically expressed and regulated in hematopoietic cells, was found to be amplified in cell lines ML-1, ML-2, and ML-3, which were separately cultured from cells of a patient with acute myelogenous leukemia (AML). A five- to tenfold amplification was correlated with high levels of expression of normal size c-myb messenger RNA and with chromosomal abnormalities in the region 6q22 -24, where the c-myb locus is normally located. Amplification and cytogenetic abnormalities were detected in DNA's from primary and secondary cultures of ML cells, suggesting that they may have contributed to leukemogenesis. The similar AML cell lines HL-60 and ML's contain different amplified oncogenes: c-myc and c-myb, respectively. Alternative activation of structurally and possibly functionally similar oncogenes may distinguish--at the pathogenetic level--phenotypically similar tumors. PMID: 6585957 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 595: Nature. 1984 Feb 2-8;307(5950):473-6. A novel 6:10 chromosomal translocation in the murine plasmacytoma NS-1. Perlmutter RM, Klotz JL, Pravtcheva D, Ruddle F, Hood L. Specific chromosomal abnormalities are regularly associated with many murine and human malignancies. In particular, the majority of murine plasmacytomas and human Burkitt's lymphomas contain a characteristic translocation which results in the juxtaposition of a cellular oncogene, c-myc, with the immunoglobulin heavy-chain gene locus, and this rearranged c-myc directs the synthesis of qualitatively and quantitatively abnormal transcripts which may have an aetiological role in the development of the transformed state in lymphoid malignancies. Similarly, rearrangement and abnormal expression of c-myb (ref. 10) and c-mos (ref. 11) has been reported in other murine lymphoid tumours. Here we describe a novel 6:10 chromosomal translocation in the murine plasmacytoma cell line NS-1 which juxtaposes the immunoglobulin Ck gene with a single-copy sequence of unknown function. The NS-1 plasmacytoma is a frequently used fusion partner in hybridoma production and is known to contain a rearranged c-myc gene and a genetic element which transforms normal mouse fibroblasts in DNA-mediated transfection assays. We conclude that individual B-cell tumours may contain multiple chromosomal translocations perhaps relevant to oncogenesis. PMID: 6420709 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 596: Princess Takamatsu Symp. 1984;15:139-45. Characteristics of three new avian sarcoma viruses, ASV 9, ASV 17, and ASV 25. Cavalieri F, Ruscio T, Tinoco R, Benedict S, Davis C, Vogt PK. Three new avian sarcoma viruses, ASV 9, ASV 17, and ASV 25, were isolated from spontaneous tumors. They transform chicken embryo fibroblasts but not hemopoietic cells and induce fibrosarcomas in young chicks. All three viruses belong to the envelope subgroup A and cannot replicate without a helper virus, because they lack the pol and most, if not all, of the env gene. ASV 9 and ASV 17 have a genome of 5.0 kb; the genome of ASV 25 is 6.0 kb. The following onc sequences were tested for homology to the genomes of the three new avian sarcoma viruses: src, fps, yes, myc, myb, erbA, and erbB. These tests were negative except for erbB which showed faint hybridization with the genome of ASV 25. ASV 9 codes for a prominent 130-kdalton gag-linked transformation-specific protein. ASV 17 and ASV 25 transformed cells appear to contain multiple gag-linked transformation-specific proteins that still require further study. PMID: 6100634 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 597: Nature. 1983 Dec 22-1984 Jan 4;306(5945):803-6. The protein products of the myc and myb oncogenes and adenovirus E1a are structurally related. Ralston R, Bishop JM. Structural and functional homologies have been found among proteins encoded by several retroviral oncogenes, demonstrating the existence of families of these genes. Because the retroviral oncogenes have cellular homologues, the existence of similar families among these 'cellular oncogenes' is also implied (for a review, see ref. 2). Cellular genes belonging to these families have been found in such evolutionarily distant species as humans, fruit flies, nematodes and brewer's yeast (E. Scolnick and S. Reed, personal communications), consistent with the hypothesis that these genes have evolved from a small number of ancestral sequences. We extend these observations by showing here that the proteins encoded by the oncogenes myc, myb and adenovirus E1a are structurally related. Our findings suggest that oncogenes of RNA and DNA tumour viruses may in at least some instances share evolutionary origins and function according to common principles. PMID: 6656884 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 598: Exp Cell Res. 1983 Nov;149(1):151-62. The cellular oncogenes c-myc, c-myb and c-erb are transcribed in defined types of avian hematopoietic cells. Coll J, Saule S, Martin P, Raes MB, Lagrou C, Graf T, Beug H, Simon IE, Stehelin D. The possible role of normal chicken cellular sequences c-erb, c-myb and c-myc, together referred to as c-onc genes and related to the oncogenes of defective avian acute leukemia retroviruses (DLVs), was investigated by determining the accumulation of c-onc RNA in different avian cells an cell lines. Levels of c-myc and in some instances c-myb RNA are elevated in immature hematopoietic cells or cell lines from various lineages but more mature hematopoietic cells, as well as non-hematopoietic cells, contain only low levels. In contrast, the level of c-erb RNA is generally low, but high in a small number of normal bone marrow cells. The results indicate that the cellular homologues of the viral oncogenes are differentially expressed during hematopoiesis. They also indicate that the hypothesis that DLV target cells express their homologous c-onc genes might hold for c-erb, but is not valid in its simple form for c-myc and c-myb. PMID: 6196212 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 599: Int J Cancer. 1983 Aug 15;32(2):185-91. Differential expression of c-erbB, c-myc and c-myb oncogene loci in human lymphomas and leukemias. Roy-Burman P, Devi BG, Parker JW. Total cellular polyadenylated RNA from a variety of fresh human lymphoma and leukemia cells, characterized by histopathology and certain cell surface markers, was analyzed for the expression of three distinct cellular oncogenes (c-onc genes), c-erbB, c-myc and c-myb by dot-blot hybridization assays. Probes used were molecularly cloned DNA containing the respective oncogene sequence of avian erythroblastosis virus, myelocytomatosis virus (MC29) and myeloblastosis virus. All lymphoma-leukemia cells irrespective of B, T or non-B/non-T lymphocyte lineage expressed the c-erbB locus. This gene was also found to be active in normal peripheral blood lymphocytes and lymphocytes from lymph nodes showing reactive hyperplasia. This observation suggested that c-erbB might be normally involved in cell growth functions since it was not unique to hematopoietic malignancies. In contrast to c-erbB, elevated expressions of c-myc or c-myb were detected in certain neoplasms of B-lymphocytes and some other lymphoproliferative disorders as compared to the majority of the samples tested which showed either low or undetectable levels of these transcripts. An examination of B-cell lymphomas and leukemias in which the majority of the cellular populations expressed either Kappa or lambda surface lg light chain molecules revealed variations in the levels of c-onc transcripts within a morphologic and immunologic subtype. These findings support the notion that, in general, genetic heterogeneity exists in groups of hematopoietic proliferations defined by conventional histopathologic and immunologic criteria. Although with the majority of the specimens there was no obvious correlation between the morphologic cell type of lymphoma/leukemia and the c-onc RNA levels, interestingly two of the three samples diagnosed as chronic lymphocytic leukemia, B-cell type, showed considerably increased transcription of the c-myc gene relative to the other B-cell neoplasms. Thus a class of differentiated B-cell leukemia has been identified in which the molecular mechanisms which affect c-myc gene expression can now be investigated. PMID: 6603429 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 600: Cancer Res. 1983 Aug;43(8):3912-8. Transcription of hematopoietic-associated oncogenes in childhood leukemia. Rosson D, Tereba A. We have examined the transcriptional expression of the cellular homologues of several retrovirus-associated oncogenes, myc, rel, rasH, myb, src, and erb, in uncultured childhood leukemia and normal hematopoietic cells, as a first step in determining their normal function and possible association with human neoplasia. Cellular myc-specific RNA was detected in all 30 samples of hematopoietic tissue examined, including 18 leukemias of both the lymphoid and myeloid series, three lymphomas, five normal leukocytes, and four cell lines. Although the level of expression varied over a 25-fold range, no general pattern based on cell type or disease state was evident. In addition, in all cell types examined, a single-molecular-weight myc-specific RNA species was observed. Transcriptional expression of the rel and rasH genes showed a similar lack of specificity, with the rasH gene being expressed at a low uniform level in all cell types examined. myb expression was marginally detectable in most samples, although the myeloid leukemia cells possessed approximately 4-fold higher levels. The expression of src was relatively low in most samples, with markedly elevated levels in a few diverse leukemia samples. erb expression was undetectable in all but two acute myelogenous leukemia samples. Analysis of one patient who had high levels of myc, erb, and src expression before therapy revealed a dramatic reduction in erb and src expression but not myc expression while the patient was in remission. These results indicate that primary human leukemia cells, as well as normal leukocytes, do express the cell homologues to several retrovirus-associated oncogenes, that some leukemia cells express high levels of several oncogenes, and that some of these genes are differentially expressed in specific subpopulations of cells. PMID: 6861153 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 601: Proc Natl Acad Sci U S A. 1983 Jul;80(13):3889-93. Human cytomegalovirus (strain AD169) contains sequences related to the avian retrovirus oncogene v-myc. Spector DH, Vacquier JP. We have detected nucleotide sequences related to the transforming gene (v-myc) of avian myelocytomatosis virus MC-29 in the DNA genome of human cytomegalovirus (HCMV) strain AD169. Cloned DNA representing the entire 1.5-kilobase-pair oncogene v-myc and subfragments of this gene were hybridized to EcoRI-cleaved HCMV virion DNA and cloned subgenomic HCMV DNA fragments. Only a 0.5-kilobase-pair Pst I-Sal I subfragment representing the 5' end of the coding sequence of the v-myc oncogene hybridized to the HCMV DNA. We have localized these v-myc-related sequences to five regions in the long unique segment of the HCMV genome corresponding to EcoRI fragments C, I, P, R, and b and to regions within the EcoRI junction fragments F and H at or near the repeats bounding the short unique segment. There was no hybridization of these HCMV sequences to other retroviral oncogenes tested including v-src, v-myb, v-erb, v-ST-fes, v-fos, v-ras (Harvey), v-mos, and v-abl. PMID: 6306648 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 602: Proc Natl Acad Sci U S A. 1983 Feb;80(4):1073-7. Increased expression of myc-related oncogene mRNA characterizes most BALB/c plasmacytomas induced by pristane or Abelson murine leukemia virus. Mushinski JF, Bauer SR, Potter M, Reddy EP. RNA blots of poly(A)-containing RNA from normal livers and spleens and from a number of transplantable hematopoietic and lymphoid BALB/c tumors, including early and late generation plasmacytomas, were hybridized with probes for four onc genes. abl RNA was abundant only in those tumors producing Abelson virus, bas RNA was found in approximately equal amounts in normal tissues and plasmacytomas, and myb RNA was absent in normal liver and plasmacytomas. Normal liver and spleen RNA showed faint traces of myc hybridization, but myc RNA was increased in most plasmacytomas. In one plasmacytoma, TEPC 1165, a particularly abundant amount of myc RNA was found, principally as a 3.5-kilobase band. In the other plasmacytomas, bands of 2.4- or 1.8-kilobase myc RNA were found. Southern blots of DNA from tumors that contained 2.4-kilobase or larger myc RNA showed myc hybridization to an EcoRI fragment of about 21 kilobase pairs, similar to the myc band in normal DNA. EcoRI digests of DNA from two tumors that expressed myc RNA of 1.8 kilobases showed an additional smaller myc band, suggesting that the myc gene is rearranged in these plasmacytomas. The basis for increased myc gene transcription in plasmacytomas is not understood, but the evidence suggests that different mechanisms may be operating in different plasmacytomas. Apparently, neither myc gene amplification nor myc gene rearrangement is required for increased myc transcription. PMID: 6302668 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 603: Hematol Oncol. 1983 Jan-Mar;1(1):61-75. Characterization of the expression of cellular retrovirus genes and oncogenes in feline cells. Busch MP, Devi BG, Soe LH, Perbal B, Baluda MA, Roy-Burman P. Expression of endogenous retrovirus genes and two different cellular oncogenes (c-onc genes) was examined at the transcriptional level in a variety of normal and lymphoma/leukemia tissues of the domestic cat. The two oncogenes, c-myb(related to avian myeloblastosis virus) and c-myc(related to avian myelocytomatosis virus) were selected for their association with the induction of hematopoietic malignancies, when present in the transforming retroviruses. Tissue-specific expression of endogenous feline leukemia virus (FeLV)-related genes was detected in cellular subpopulations of the cat placenta by in situ method of hybridization. Gel blotting analysis of placental poly(A)-selected RNA revealed that the FeLV-related RNA species were primarily subgenomic, representing the env gene region of the endogenous provirus elements. Like the endogenous retrovirus genes, c-myb and c-myc loci of the cat genomic DNA were also transcribed at differential levels in normal tissues of the cat. Dot-blot hybridization analysis showed that the expression of these two oncogenes was linked to growth and development as it varied with the gestational age of the fetus and from fetal to adult tissues. Among the major hematopoietic organs, spleen and bone marrow contained both c-myb and c-myc transcripts, while thymus preferentially expressed the c-myb gene. In contrast to the low level of c-myc expression in fetal thymus tissues, enhanced c-myc expression was detected in all five thymomas tested and also in several other neoplasms including two granulocytic leukemias. The feline c-myb gene was not very active in granulocytic leukemias or in three of the five thymomas. RNA gel blotting analysis of poly(A)-selected RNA of a thymoma and its lymph node metastasis showed identical pattern of c-myc transcripts. PMID: 6329934 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 604: EMBO J. 1983;2(12):2385-9. Quail embryo fibroblasts transformed by four v-myc-containing virus isolates show enhanced proliferation but are non tumorigenic. Palmieri S, Kahn P, Graf T. Quail embryo fibroblasts infected with any of the four natural avian myc gene-containing virus strains (MC29, CMII, OK10 and MH2) or with the myb, ets-containing E26 acute leukemia virus, were examined for their expression of several transformation-associated parameters. All myc-containing viruses, but not E26 or Rous sarcoma virus (used as a control) induced a dramatic stimulation of cell proliferation. In addition, the myc virus-transformed cells exhibited prominent nucleoli, possibly as a consequence of their increased proliferation. Cells transformed by MC29, OK10, MH2 and E26 were capable of growing in semi-solid medium and showed a loss of actin cables and, in most cases, of an ordered fibronectin distribution. All of the myc virus-transformed fibroblasts, as well as the E26-transformed cells, were unable to form tumors in nude mice, indicating that the myc gene (and the myb/ets genes) are not sufficient for the induction of a fully malignant phenotype in avian fibroblasts. PMID: 6321165 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 605: Gene Amplif Anal. 1983;3:147-74. High-level expression of oncogenes in Escherichia coli. Lautenberger JA, Kan NC, Court D, Pry T, Showalter S, Papas TS. Laboratory of Molecular Oncology, National Cancer Institute, Bethesda, Maryland 20205. A plasmid, pJL6, was constructed that contains a unique Cla I site 12 codons beyond the bacteriophage lambda cII gene initiation codon, as well as an adjacent unique Hind III site. These sites allowed us to fuse the sequences from the avian myelocytomatosis virus (MC29) v-myc gene, the avian myeloblastosis virus (AMV) v-myb gene, and the Harvey murine sarcoma virus (Ha-MuSV) v-ras gene to the amino-terminal portion of the cII gene. Transcription of the hybrid genes is controlled from the lambda PL promoter. When this promoter is derepressed, E. coli cells harboring the chimeric plasmid produce levels of fusion proteins that amount to over 5% of total cellular protein. Antibodies raised by the cII-myc fusion protein form an immunoprecipitate with the MC29 gene product, P110gag-myc. The cII-ras fusion protein is precipitated by monoclonal antibodies directed toward the Ha-MSV p21ras, binds GDP, and is capable of autophosphorylation. PMID: 6101025 [PubMed - indexed for MEDLINE] ---------------------------------------------------------------