1: J Cell Physiol. 2006 Jan;206(1):280-1. 

MEK hyperphosphorylation coincides with cell cycle shut down of cultured smooth
muscle cells.

Vogel S, Kubin T, von der Ahe D, Deindl E, Schaper W, Zimmermann R.

Department of Experimental Cardiology, Max Planck Institute, Bad Nauheim,
Germany.

Smooth muscle cells (SMCs) form the backbone of arteries and their proliferation
hallmarks collateral vessel growth, a process termed arteriogenesis, as well as
pathogenic responses such as restenosis. Since signaling pathways in SMCs are
the main targets for therapeutic interventions, we aimed to determine how and to
what extent the activation of the ubiquitous MEK-ERK signaling pathway
correlates with important in vivo phenomena such as dedifferentiation, nuclear
activation, and proliferation of SMCs. Specificity of this pathway was monitored
using MEK inhibitors UO126 and PD98059 in platelet derived growth factor-AB
(PDGF-AB) and fibroblast growth factor-2 (FGF-2)-stimulated SMCs. PDGF-AB
induced a rapid MEK activation followed by phosphorylation of the MEK substrates
ERK1/2, while FGF-2 showed a less pronounced and delayed activation. Both growth
factors triggered a marked phosphorylation of c-Myc and expression of Egr1.
Pretreatment with MEK inhibitors suppressed the activation of the ERK cascade,
abolished the downregulation of desmin and led to cell-cycle arrest. However,
the reversibility of p27(Kip1) downregulation by UO126 was mainly observed after
PDGF-AB stimulation, indicating MEK independent p27(Kip1) downregulation by
FGF-2. Surprisingly, treatment of SMCs with UO126 or PD98059 increased the level
of MEK phosphorylation in a dose-dependent manner at serine residues 217/221 in
the presence as well as in the absence of both growth factors. Our results
strongly imply that depending on the environmental context phosphorylation of
serines 217/221 serves as an "on" as well as an "off " switch. (c) 2005
Wiley-Liss, Inc.The original article to which this Erratum refers was published
online on 26 May 2005 J Cell Physiol 2005;DOI 10.1002/jcp.20437.

PMID: 16136547 [PubMed - in process]


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2: J Cell Physiol. 2006 Jan;206(1):25-34. 

MEK hyperphosphorylation coincides with cell cycle shut down of cultured smooth
muscle cells.

Vogel S, Kubin T, von der Ahe D, Deindl E, Schaper W, Zimmermann R.

Department of Experimental Cardiology, Max Planck Institute, Bad Nauheim,
Germany.

Smooth muscle cells (SMCs) form the backbone of arteries and their proliferation
hallmarks collateral vessel growth, a process termed arteriogenesis, as well as
pathogenic responses such as restenosis. Since signaling pathways in SMCs are
the main targets for therapeutic interventions, we aimed to determine how and to
what extent the activation of the ubiquitous MEK-ERK signaling pathway
correlates with important in vivo phenomena such as dedifferentiation, nuclear
activation and proliferation of SMCs. Specificity of this pathway was monitored
using MEK inhibitors UO126 and PD98059 in platelet derived growth factor-AB
(PDGF-AB)- and fibroblast growth factor-2 (FGF-2)-stimulated SMCs. PDGF-AB
induced a rapid MEK activation followed by phosphorylation of the MEK substrates
ERK1/2 while FGF-2 showed a less pronounced and delayed activation. Both growth
factors triggered a marked phosphorylation of c-Myc and expression of Egr1.
Pretreatment with MEK inhibitors suppressed the activation of the ERK cascade,
abolished the down-regulation of desmin and led to cell cycle arrest. However,
the reversibility of p27(Kip1) down-regulation by UO126 was mainly observed
after PDGF-AB stimulation, indicating MEK independent p27(Kip1) down-regulation
by FGF-2. Surprisingly, treatment of SMCs with UO126 or PD98059 increased the
level of MEK phosphorylation in a dose dependent manner at serine residues
217/221 in the presence as well as in the absence of both growth factors. Our
results strongly imply that depending on the environmental context
phosphorylation of serines 217/221 serves as an "on" as well as an "off "
switch. (c) 2005 Wiley-Liss, Inc.

PMID: 15920755 [PubMed - in process]


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3: Blood. 2005 Aug 15;106(4):1382-91. Epub 2005 May 12. 

c-Jun N-terminal kinase (JNK) is required for survival and proliferation of
B-lymphoma cells.

Gururajan M, Chui R, Karuppannan AK, Ke J, Jennings CD, Bondada S.

Department of Microbiology, Immunology, & Molecular Genetics, University of
Kentucky, Lexington, KY, USA.

Several primary murine and human B lymphomas and cell lines were found to
constitutively express high levels of the activated form of c-jun N-terminal
kinase (JNK), a member of the mitogen-activated protein (MAP) kinase family.
Proliferation of murine B lymphomas CH31, CH12.Lx, BKS-2, and WEHI-231 and the
human B lymphomas BJAB, RAMOS, RAJI, OCI-Ly7, and OCI-Ly10 was strongly
inhibited by SP600125, an anthrapyrazolone inhibitor of JNK, in a dose-dependent
manner. The lymphoma cells underwent apoptosis and arrested at the G2/M phase of
cell cycle. Furthermore, JNK-specific small interfering RNA (siRNA) inhibited
the growth of both murine and human B lymphomas. Thus in the B-lymphoma model,
JNK appears to have a unique prosurvival role. Survival signals provided by CD40
and interleukin-10 (IL-10) together reversed the growth inhibition induced by
the JNK inhibitor. c-Myc protein levels were reduced in the presence of both
SP600125 and JNK-specific siRNA, and CD40 ligation restored c-Myc levels.
Moreover, Bcl-xL rescued WEHI-231 cells from apoptosis induced by the JNK
inhibitor. The JNK inhibitor also reduced levels of early growth response gene-1
(Egr-1) protein, and overexpressing Egr-1 partially rescued lymphoma cells from
apoptosis. Thus, JNK may act via c-Myc and Egr-1, which were shown to be
important for B-lymphoma survival and growth.

PMID: 15890690 [PubMed - indexed for MEDLINE]


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4: Ultrasound Med Biol. 2005 May;31(5):703-8. 

Early gene response to low-intensity pulsed ultrasound in rat osteoblastic
cells.

Sena K, Leven RM, Mazhar K, Sumner DR, Virdi AS.

Department of Anatomy and Cell Biology, Rush University Medical Center, 600 S.
Paulina Street, Chicago, IL 60612, USA.

The aim of the current research was to quantify the changes in gene expression
in rat bone marrow derived stromal cells (BMSC) to low intensity pulsed
ultrasound (LIPUS) during early time points after the ultrasound application.
LIPUS at 1.5 MHz, 30 mW/cm(2) was applied to BMSC for a single 20 min treatment.
Real-time PCR was carried out to quantify the expression of early response genes
and bone differentiation marker genes 0.5, 1, 3, 6 and 12 h after the end of the
LIPUS treatment. Compared with the controls, LIPUS treatment resulted in
elevated transient expression of early response genes (c-jun, c-myc, COX-2,
Egr-1, TSC-22) as well as the bone differentiation marker genes, osteonectin and
osteopontin, at 3 h. This induction of early response genes as well as
extracellular matrix genes associated with cell proliferation and
differentiation may represent the effect of LIPUS to cells of osteoblastic
lineage.

PMID: 15866420 [PubMed - indexed for MEDLINE]


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5: Cancer Genet Cytogenet. 2005 May;159(1):1-9. 

A combination of molecular cytogenetic analyses reveals complex genetic
alterations in conventional renal cell carcinoma.

Strefford JC, Stasevich I, Lane TM, Lu YJ, Oliver T, Young BD.

Cancer Research UK Medical Oncology Unit, Queen Mary University of London,
Charterhouse Square, London, UK. jcs@soton.ac.uk

Here we report the complex pattern of genomic imbalances and rearrangements in a
panel of 19 renal cell carcinoma cell lines detected with molecular cytogenetic
analysis. Consistent heterogeneity in chromosome number was found, and most cell
lines showed a near-triploid chromosome complement. Several cell lines showed
deletions of the TP53 (alias p53), CDKN2A (alias p16), and VHL genes. Multiplex
fluorescence in situ hybridization (M-FISH) analysis revealed chromosome 3
translocated to several other partners chromosomes, as well as breakage events
commonly affecting chromosomes 1, 5, 8, 10, and 17. The most common abnormality
detected with comparative genomic hybridization (CGH) was deletions of
chromosome 3p, with loss of the RASSF1, FHIT, and p44S10 loci frequently
involved. CGH gain of 5q showed overrepresentation of the EGR1 and CSF1R genes.
Recurrent alterations to chromosome 7 included rearrangement of 7q11 and gains
of the EGFR, TIF1, and RFC2 genes. Several lines exhibited rearrangement of
12q11 approximately q14 and overrepresentation of CDK4 and SAS loci. M-FISH
revealed several other recurrent translocations, and CGH findings included loss
of 9p, 14q, and 18q and gain of 8q, 12, and 20. Further genomic microarray
changes included loss of MTAP, IGH@, HTR1B, and SMAD4 (previously MADH4) and
gains of MYC and TOP1. An excellent correlation was observed between the genomic
array and FISH data, demonstrating that this technique is effective and
accurate. The aberrations detected here may reflect important pathways in renal
cancer pathogenesis.

PMID: 15860350 [PubMed - indexed for MEDLINE]


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6: Blood. 2005 Aug 1;106(3):871-8. Epub 2005 Apr 19. 

Egr-1 abrogates the block imparted by c-Myc on terminal M1 myeloid
differentiation.

Shafarenko M, Liebermann DA, Hoffman B.

Fels Institute for Cancer Research and Molecular Biology, Temple University
School of Medicine, 3307 N Broad St, Philadelphia, PA 19140, USA.

Both deregulated growth and blocks in differentiation cooperate in the
multistage process of leukemogenesis. Thus, understanding functional
interactions between genes that regulate normal blood cell development,
including cell growth and differentiation, and how their altered expression
contributes to leukemia, is important for rational drug design. Previously, we
have shown that the zinc finger transcription factor Egr-1 plays a role in
monocytic differentiation. Ectopic expression of Egr-1 in M1 myeloblastic
leukemia cells was observed to activate the macrophage differentiation program
in the absence of the differentiation inducer interleukin 6 (IL-6) and to
promote terminal differentiation in its presence. In addition, we have shown
that deregulated expression of the proto-oncogene c-myc blocks the myeloid
terminal differentiation program. Here we show that restoring expression of
Egr-1 in M1 cells that express deregulated c-Myc abrogates the c-Myc block in
terminal differentiation, resulting in cells that undergo functional macrophage
maturation. However, there is an absence of both growth arrest and cell
adhesion. In addition, Egr-1 expression diminished M1myc leukemogenicity in
vivo. These findings indicate that Egr-1 can act as a tumor suppressor gene and
suggest that Egr-1 or Egr-1 targets may provide important tools for
differentiation therapy in certain leukemic phenotypes.

PMID: 15840692 [PubMed - indexed for MEDLINE]


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7: J Biol Chem. 2005 Jun 10;280(23):22172-80. Epub 2005 Apr 7. 

Thrombin modulates the expression of a set of genes including thrombospondin-1
in human microvascular endothelial cells.

McLaughlin JN, Mazzoni MR, Cleator JH, Earls L, Perdigoto AL, Brooks JD,
Muldowney JA 3rd, Vaughan DE, Hamm HE.

Department of Pharmacology, Division of Cardiovascular Medicine, Vanderbilt
University Medical Center, 444 Robinson Research Building, 23rd Avenue South at
Pierce, Nashville, TN 37232 , USA. joseph.mclaughlin@vanderbilt.edu

Thrombospondin-1 (THBS1) is a large extracellular matrix glycoprotein that
affects vasculature systems such as platelet activation, angiogenesis, and wound
healing. Increases in THBS1 expression have been liked to disease states
including tumor progression, atherosclerosis, and arthritis. The present study
focuses on the effects of thrombin activation of the G-protein-coupled,
protease-activated receptor-1 (PAR-1) on THBS1 gene expression in the
microvascular endothelium. Thrombin-induced changes in gene expression were
characterized by microarray analysis of approximately 11,000 different human
genes in human microvascular endothelial cells (HMEC-1). Thrombin induced the
expression of a set of at least 65 genes including THBS1. Changes in THBS1 mRNA
correlated with an increase in the extracellular THBS1 protein concentration.
The PAR-1-specific agonist peptide (TFLLRNK-PDK) mimicked thrombin stimulation
of THBS1 expression, suggesting that thrombin signaling is through PAR-1.
Further studies showed THBS1 expression was sensitive to pertussis toxin and
protein kinase C inhibition indicating G(i/o)- and G(q)-mediated pathways. THBS1
up-regulation was also confirmed in human umbilical vein endothelial cells
stimulated with thrombin. Analysis of the promoter region of THBS1 and other
genes of similar expression profile identified from the microarray predicted an
EBOX/EGRF transcription model. Expression of members of each family, MYC and
EGR1, respectively, correlated with THBS1 expression. These results suggest
thrombin formed at sites of vascular injury increases THBS1 expression into the
extracellular matrix via activation of a PAR-1, G(i/o), G(q),
EBOX/EGRF-signaling cascade, elucidating regulatory points that may play a role
in increased THBS1 expression in disease states.

PMID: 15817447 [PubMed - indexed for MEDLINE]


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8: Crit Rev Eukaryot Gene Expr. 2004;14(4):287-300. 

Neuroendocrine cells in prostate cancer.

Amorino GP, Parsons SJ.

Department of Microbiology, University of Virginia Health Sciences Center,
Charlottesville, VA 22908, USA.

Neuroendocrine (NE) cells are found in prostate tumors, and their incidence is
considered a promising prognostic indicator for the development of
androgen-independent disease. NE cells are derived from non-NE prostate cancer
cells and secrete factors that can act in a paracrine manner to stimulate the
survival, growth, motility, and metastatic potential of prostatic carcinoma
cells. Factors such as IL-6, epinephrine, and forskolin induce NE
differentiation in prostate cancer cells; the mechanisms involve increases in
intracellular cAMP, protein kinase A (PKA) activation and reduced intracellular
calcium levels. Transcription factors implicated in the acquisition of NE
characteristics by prostate cancer cells include STAT3, CREB, EGR1, c-fos, and
NF-kappaB. Expression of Chromogranin A, neuron-specific enolase, bcl-2, and the
androgen receptor are modulated during NE differentiation and serve as molecular
markers for NE cells. Most importantly, NE cells secrete neuropeptides, such as
bombesin, neurotensin, PTHrP, serotonin, and calcitonin, which trigger growth
and survival responses in androgen-independent prostate cancer cells. Prostate
cancer cell receptors that play a role in these processes include the
gastrin-releasing peptide (GRP) receptor, neurotensin receptors, and the
epidermal growth-factor receptor (EGFR). Signal-transduction molecules activated
by these neuropeptides include Src, focal adhesion kinase (FAK), ERK, and
PI3K/Akt, with subsequent activation of Elk-1, NF-kappaB, and c-myc
transcription factors. A multitude of genes are then expressed by prostate
cancer cells, which are involved in proliferation, anti-apoptosis, migration,
metastasis, and angiogenesis. Targeting of these pathways at multiple levels can
be exploited to inhibit the process by which NE cells contribute to the
progression of androgen-independent, treatment-refractory prostate cancer.

Publication Types:
    Review

PMID: 15663358 [PubMed - indexed for MEDLINE]


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9: Toxicol Lett. 2004 Dec 30;154(3):191-200. 

Cadmium at a non-toxic dose alters gene expression in mouse testes.

Zhou T, Jia X, Chapin RE, Maronpot RR, Harris MW, Liu J, Waalkes MP, Eddy EM.

Gamete Biology Section, Laboratory of Reproductive and Developmental Toxicology,
National Institute of Environmental Health Sciences, National Institutes of
Health, Research Triangle Park, NC 27709, USA.

The testes are important targets of cadmium (Cd)-induced toxicity and
carcinogenicity in rodents. Exposure to Cd at environmentally relevant low
levels is a significant human health concern, but the effects of Cd on the
rodent testes at doses that do not cause overt lesions are poorly defined. We
used cDNA microarray and quantitative real-time RT-PCR assays to determine gene
expression profiles in the testes of CD-1 mice 12-72 h after a single s.c.
injection of 5 micromol/kg CdCl2. This dose of Cd did not produce overt
histopathological changes, but clearly altered the expression of some genes that
are likely to be important in toxicity responses. The most significant changes
in gene expression occurred 24 h after treatment, corresponding to when the
highest level of Cd was detected in the testes. Increased expression of the
C-myc and Egr1 genes strongly suggests acute stress responses. Repressed
expression of cell cycle-regulated cyclin B1 and CDC2 proteins indicates a
potential for causing G2/M arrest and disturbance of meiosis. Decreased
expression of pro-apoptotic genes, particularly Casp3, and DNA repair genes
possibly contributes to Cd-induced carcinogenesis. These results indicate that
changes in gene expression occur well before overt effects of Cd-induced
testicular toxicity and carcinogenicity are apparent.

PMID: 15501611 [PubMed - indexed for MEDLINE]


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10: Nucleic Acids Res. 2004 Sep 23;32(17):4955-61. Print 2004. 

In silico identification of transcriptional regulators associated with c-Myc.

Elkon R, Zeller KI, Linhart C, Dang CV, Shamir R, Shiloh Y.

The David and Inez Myers Laboratory for Genetic Research, Department of Human
Genetics, Sackler School of Medicine, Tel Aviv University, Israel.

The development of powerful experimental strategies for functional genomics and
accompanying computational tools has brought major advances in the delineation
of transcriptional networks in organisms ranging from yeast to human. Regulation
of transcription of eukaryotic genes is to a large extent combinatorial. Here,
we used an in silico approach to identify transcription factors (TFs) that form
recurring regulatory modules with c-Myc, a protein encoded by an oncogene that
is frequently disregulated in human malignancies. A recent study identified, on
a genomic scale, human genes whose promoters are bound by c-Myc and its
heterodimer partner Max in Burkitt's lymphoma cells. Using computational
methods, we identified nine TFs whose binding-site signatures are highly
overrepresented in this promoter set of c-Myc targets, pointing to possible
functional links between these TFs and c-Myc. Binding sites of most of these TFs
are also enriched on the set of mouse homolog promoters, suggesting functional
conservation. Among the enriched TFs, there are several regulators known to
control cell cycle progression. Another TF in this set, EGR-1, is rapidly
activated by numerous stress challenges and plays a central role in
angiogenesis. Experimental investigation confirmed that c-Myc and EGR-1 bind
together on several target promoters. The approach applied here is general and
demonstrates how computational analysis of functional genomics experiments can
identify novel modules in complex networks of transcriptional regulation.

Publication Types:
    Evaluation Studies

PMID: 15388797 [PubMed - indexed for MEDLINE]


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11: Oncogene. 2003 Nov 13;22(51):8246-54. 

DeltaNp73 can modulate the expression of various genes in a p53-independent
fashion.

Kartasheva NN, Lenz-Bauer C, Hartmann O, Schafer H, Eilers M, Dobbelstein M.

Institut fur Virologie, Philipps-Universitat Marburg, Robert Koch Str. 17,
Marburg 35037, Germany.

DeltaNp73alpha is an isoform of the p53 homologue p73 that lacks an
amino-terminal transactivation domain and antagonizes the induction of gene
expression by p53. Here, we examined whether DeltaNp73alpha might also modulate
cellular transcription in the absence of p53. The expression of DeltaNp73alpha
in the p53-/- cell line H1299 reduced the mRNA levels of p21/CDKN1A, but did not
affect other p53-responsive genes. Correspondingly, the p21/CDKN1A promoter was
downregulated by DeltaNp73alpha in reporter assays, whereas other p53-responsive
promoters were not inhibited. To identify additional genes that respond to
DeltaNp73alpha in the absence of p53, microarrays carrying 4600 cDNA clones were
hybridized. The expression of 30 genes was found to be altered more than
threefold by overexpressed DeltaNp73alpha. For instance, DeltaNp73alpha
increased the expression of EGR1 and CDC6, whereas it decreased the mRNA levels
of c-MYC, cyclin A2/CCNA2, NF-kappaB1, ODC1, and RET finger protein/RFP.
Semiquantitative reverse transcription-PCR confirmed these results and further
revealed that the influence of DeltaNp73alpha on the regulation of these genes
differs from other p73 isoforms and p53. We conclude that the impact of
DeltaNp73alpha on gene expression is not limited to p53-responsive genes.
Rather, DeltaNp73alpha can regulate the expression of a variety of genes
independently of p53.

PMID: 14614448 [PubMed - indexed for MEDLINE]


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12: Nucleic Acids Res. 2003 Jul 15;31(14):3954-62. 

Transient recruitment of the hnRNP K protein to inducibly transcribed gene loci.

Ostrowski J, Kawata Y, Schullery DS, Denisenko ON, Bomsztyk K.

Department of Medicine, University of Washington, Seattle, WA 98195, USA.

The heterogeneous nuclear ribonucleoprotein K protein is an RNA- and DNA-binding
protein implicated in the regulation of multiple processes that comprise gene
expression. We used chromatin immunoprecipitation (ChIP) assays to explore K
protein interactions with serum-inducible, constitutively expressed and
untranscribed gene loci in vivo. In the rat HTC-IR hepatoma cell line, serum
treatment induced transient increases in the mRNA levels of two immediate-early
genes, egr-1 and c-myc. ChIP analysis showed that the induction of egr-1 and
c-myc genes was associated with a transient recruitment of K protein to multiple
sites within each of these loci, including the promoter and transcribed regions.
In contrast, recruitment of K protein to the constitutively transcribed
beta-actin locus and to randomly chosen non-transcribed loci was far weaker. In
rat mesangial cells, c-myc was constitutively expressed while egr-1 remained
serum responsive. In these cells, ChIP analysis showed serum-induced recruitment
to the inducible egr-1 but not to the c-myc locus. Pre-treatment with the
transcription inhibitor actinomycin D blocked the inducible but not the
constitutive binding of K protein to these loci. Taken together, the results of
this study suggest that the transient recruitment of K protein to
serum-responsive loci depends on the inducible transcription of these
immediate-early genes.

PMID: 12853611 [PubMed - indexed for MEDLINE]


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13: Oncogene. 2003 Jun 12;22(24):3821-6. 

Upregulation of c-MYC in WT1-mutant tumors: assessment of WT1 putative
transcriptional targets using cDNA microarray expression profiling of
genetically defined Wilms' tumors.

Udtha M, Lee SJ, Alam R, Coombes K, Huff V.

Department of Molecular Genetics/Cancer Genetics, The University of Texas MD
Anderson Cancer Center, Houston 77030, USA.

The Wilms' tumor suppressor gene, WT1, functions as a transcriptional regulator
that represses or activates the expression of a variety of putative target
genes. However, it is not clear which genes are the biological targets of WT1,
nor which cellular pathway(s) is critically altered in tumors as a result of WT1
mutation. To investigate in vivo the role of WT1 as a transcription factor in
Wilms' tumors, we used cDNA microarrays to compare the expression of putative
WT1 target genes in a set of 15 primary Wilmstumors carrying WT1-inactivating
mutations versus a set of 16 tumors with no WT1 mutations. We hypothesized that
the expression of direct downstream targets of WT1 that are relevant to tumor
development would differ between these two genetically distinct sets of tumors.
Using the Atlas Human Cancer 1.2 cDNA arrays to quantitate gene expression in
the 31 tumors, we found that the expression of one WT1 putative target gene,
c-MYC, statistically significantly differed between the two sets of tumors and
was upregulated in WT1-mutant tumors. This increase of relative gene expression
for c-MYC was confirmed using real-time reverse transcription-polymerase chain
reaction. The differential expression of another putative target gene, EGR1,
approached significance and was also upregulated in WT1-mutant tumors. These
data, in addition to the coexpression of c-MYC and WT1 in embryonic renal
mesenchyme, strongly suggest that c-MYC is a biologically relevant target of WT1
in Wilmstumors.

PMID: 12802290 [PubMed - indexed for MEDLINE]


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14: Int J Oncol. 2003 Jul;23(1):49-59. 

Differential gene expression profiles and identification of the genes relevant
to clinicopathologic factors in colorectal cancer selected by cDNA array method
in combination with principal component analysis.

Tsunoda T, Koh Y, Koizumi F, Tsukiyama S, Ueda H, Taguchi F, Yamaue H, Saijo N,
Nishio K.

Department of Surgery and Bioengineering Advanced Clinical Research Center,
Institute of Medical Science of Tokyo, Shiroganedai 4-6-1, Minato-Ku, Tokyo
108-8639, Japan.

The clinical outcome of patients with colorectal cancer frequently varies even
if they are at the same clinicopathologic stage. Alternative superior tumor
markers of colorectal cancer are needed for prediction of clinical outcome. To
clarify the regulatory factors in colorectal cancers, we examined differential
expression profiles using cDNA macroarray technique with surgically resected
specimens obtained from the patients with colorectal cancer. The gene profiles
by an average-linkage hierarchical clustering analysis were found to be almost
separable into two groups: tumor group and normal mucosa group. The relationship
between several clinicopathologic factors and cancer related genes were
investigated by using statistical analyses including principal component
analysis (PCA). c-myc-binding protein MM-1, and c-jun proto-oncogene were
identified as possible markers of tumor histology and clinical prognosis and
early growth response protein 1 (EGR1) was selected to play an important role in
progression of clinical stage. We conclude that, with PCA method, we
successfully selected the genes relevant to clinicopathologic factors using
limited population of clinical samples.

PMID: 12792775 [PubMed - indexed for MEDLINE]


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15: Genes Chromosomes Cancer. 2003 Jul;37(3):270-81. 

Erratum in:
    Genes Chromosomes Cancer. 2003 Jul;37(3):332.

Cytogenetic, spectral karyotyping, fluorescence in situ hybridization, and
comparative genomic hybridization characterization of two new secondary leukemia
cell lines with 5q deletions, and MYC and MLL amplification.

Knutsen T, Pack S, Petropavlovskaja M, Padilla-Nash H, Knight C, Mickley LA,
Ried T, Elwood PC, Roberts SJ.

Genetics Branch, National Cancer Institute, National Institutes of Health,
Bethesda, Maryland 20892, USA. knutsent@mail.nih.gov

Cytogenetic studies of patients with therapy-induced acute myeloid leukemia
(t-AML) have demonstrated whole chromosome loss or q-arm deletion of chromosomes
5 and/or 7 in a majority of cases. We have established two cell lines, SAML-1
and SAML-2, from two patients who developed t-AML after radiation and
chemotherapy for Hodgkin disease. In both cases, the leukemia cells contained 5q
deletions. SAML-1 has 58 chromosomes and numerous abnormalities, including
der(1)(1qter-->1p22::5q31-->5qter), der(5)(5pter-->5q22::1p22-->1pter), +8,
der(13)i(13)(q10)del(13)(q11q14.1), and t(10;11). Fluorescence in situ
hybridization (FISH) with unique sequence probes for the 5q31 region showed loss
of IL4, IL5, IRF1, and IL3, and translocation of IL9, DS5S89, EGR1, and CSFIR to
1p. SAML-2 has 45 chromosomes, del(5)(q11.2q31) with a t(12;13)ins(12;5),
leading to the proximity of IRF1 and RB1, and complex translocations of
chromosomes 8 and 11, resulting in amplification of MYC and MLL. Comparative
genomic hybridization and spectral karyotyping were consistent with the
G-banding karyotype and FISH analyses. Because a potential tumor suppressor(s)
in the 5q31 region has yet to be identified, these cell lines should prove
useful in the study of the mechanisms leading to the development of t-AML.
Copyright 2003 Wiley-Liss, Inc.

PMID: 12759925 [PubMed - indexed for MEDLINE]


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16: J Immunol. 2003 May 1;170(9):4578-92. 

The cyclopentenone-type prostaglandin 15-deoxy-delta 12,14-prostaglandin J2
inhibits CD95 ligand gene expression in T lymphocytes: interference with
promoter activation via peroxisome proliferator-activated
receptor-gamma-independent mechanisms.

Cippitelli M, Fionda C, Di Bona D, Lupo A, Piccoli M, Frati L, Santoni A.

Dipartimento di Medicina Sperimentale e Patologia, Istituto Pasteur-Fondazione
Cenci Bolognetti, University La Sapienza, Rome, Italy.

15-Deoxy-delta(12,14)-PGJ(2) (15d-PGJ(2)) is a cyclopentenone-type PG endowed
with anti-inflammatory properties and produced by different cells, including
those of the immune system. 15d-PGJ(2) is a natural ligand of the peroxisome
proliferator-activated receptor (PPAR)-gamma nuclear receptor, but relevant
PPARgamma-independent actions mediated by this prostanoid have been described.
Fas (APO-1/CD95) and its ligand (Fas-L) are cell surface proteins whose
interaction activates apoptosis of Fas-expressing targets. In T cells, the
Fas-Fas-L system regulates activation-induced cell death and has been implicated
in diseases in which lymphocyte homeostasis is compromised. Moreover, several
studies have described the pathogenic functions of Fas and Fas-L in vivo,
particularly in the induction-progression of organ-specific autoimmune diseases.
In this study we describe the effect of 15d-PGJ(2) on the activation of the
fas-L gene in T lymphocytes. We show that 15d-PGJ(2) inhibits fas-L mRNA
expression, activation-induced cell death, and fas-L promoter activity by
mechanisms independent of PPARgamma and mediated by its chemically reactive
cyclopentenone moiety. Our data indicate that 15d-PGJ(2) may repress fas-L
activation by interfering with the expression and/or transcriptional activity of
different transcription factors (early growth response types 3 and 1, NF-kappaB,
AP-1, c-Myc, Nur77) whose altered balancing and transactivation may contribute
for overall repression of this gene. In addition, the activation/expression of
the heat shock response genes HSF-1 and HSP70 is not directly involved in the
repression, and the electrophilic molecule cyclopentenone (2-cyclopenten-1-one)
may reproduce the effects mediated by 15d-PGJ(2). These results suggest that
modulation of Fas-L by 15d-PGJ(2) in T cells may represent an additional tool to
consider for treatment of specific autoimmune and inflammatory disorders.

PMID: 12707336 [PubMed - indexed for MEDLINE]


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17: Physiol Genomics. 2001 Dec 21;7(2):105-14. 

Identification of AKT-regulated genes in inducible MERAkt cells.

Kuhn I, Bartholdi MF, Salamon H, Feldman RI, Roth RA, Johnson PH.

Departments of Cancer Research, Genomics and Gene Therapy, Immunology, Berlex
Biosciences, Richmond 94804-0099, USA. Irene_Kuhn@Berlex.com

AKT/protein kinase B plays a critical role in the phosphoinositide 3-kinase
(PI3-kinase) pathway regulating cell growth, differentiation, and oncogenic
transformation. Akt1-regulated genes were identified by cDNA array hybridization
analysis using an inducible AKT1 protein, MERAKT. Treatment of MERAkt cells with
estrogen receptor ligands resulted in phosphorylative activation of MERAKT.
Genes differentially expressed in MERAkt/NIH3T3 cells treated with tamoxifen,
raloxifene, ICI-182780, and ZK955, were identified at 3 and 20 h. AKT activation
resulted in the repression of c-myc, early growth response 1 (EGR1),
transforming growth factor beta receptor III (TGF-betar III), and
thrombospondin-1 (THBS1). Although c-myc induction is often associated with
oncogenic transformation, the c-myc repression observed here is consistent with
the anti-apoptotic function of AKT. Repression of THBS1 and EGR1 is consistent
with the known pro-angiogenic functions of AKT. AKT-regulated genes were found
to be largely distinct from platelet-derived growth factor-beta
(PDGFbeta)-regulated genes; only T-cell death-associated gene 51 (TDAG51) was
induced in both cases. In contrast to their repression by AKT, c-myc, THBS1, and
EGR1 were induced by PDGFbeta, indicating negative interference between elements
upstream and downstream of AKT1 in the PDGFbeta signal transduction pathway.

PMID: 11773597 [PubMed - indexed for MEDLINE]


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18: Proc Natl Acad Sci U S A. 2001 Jun 5;98(12):6674-9. 

Stat1-independent regulation of gene expression in response to IFN-gamma.

Ramana CV, Gil MP, Han Y, Ransohoff RM, Schreiber RD, Stark GR.

Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue,
Cleveland, OH 44195, USA.

Although Stat1 is essential for cells to respond fully to IFN-gamma, there is
substantial evidence that, in the absence of Stat1, IFN-gamma can still regulate
the expression of some genes, induce an antiviral state and affect cell growth.
We have now identified many genes that are regulated by IFN-gamma in
serum-starved Stat1-null mouse fibroblasts. The proteins induced by IFN-gamma in
Stat1-null cells can account for the substantial biological responses that
remain. Some genes are induced in both wild-type and Stat1-null cells and thus
are truly Stat1-independent. Others are subject to more complex regulation in
response to IFN-gamma, repressed by Stat1 in wild-type cells and activated in
Stat1-null cells. Many genes induced by IFN-gamma in Stat1-null fibroblasts also
are induced by platelet-derived growth factor in wild-type cells and thus are
likely to be involved in cell proliferation. In mouse cells expressing the
docking site mutant Y440F of human IFN-gamma receptor subunit 1, the mouse Stat1
is not phosphorylated in response to human IFN-gamma, but c-myc and c-jun are
still induced, showing that the Stat1 docking site is not required for
Stat1-independent signaling.

PMID: 11390994 [PubMed - indexed for MEDLINE]


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19: J Immunol. 2001 Jan 15;166(2):1028-40. 

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating
polypeptide inhibit expression of Fas ligand in activated T lymphocytes by
regulating c-Myc, NF-kappa B, NF-AT, and early growth factors 2/3.

Delgado M, Ganea D.

Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA.

Activation-induced cell death in T cells, a major mechanism for limiting an
ongoing immune response, is initiated by Ag reengagement and mediated through
Fas/Fas ligand interactions. Vasoactive intestinal peptide (VIP) and pituitary
adenylate cyclase-activating polypeptide (PACAP), two multifunctional
neuropeptides, modulate innate and adaptive immunity. We reported previously
that VIP/PACAP protect T cells from activation-induced cell death through
down-regulation of Fas ligand (FasL). In this study, we investigate the
molecular mechanisms involved in the protective effect of VIP and PACAP.
VIP/PACAP reduce in a dose-dependent manner anti-CD3-induced apoptosis in 2B4.11
T cell hybridomas. The protective effect is mediated through the specific type 2
VIP receptor, and the cAMP/protein kinase A pathway. A functional study
demonstrates that VIP/PACAP inhibit activation-induced FasL expression.
VIP/PACAP inhibit the expression and/or DNA-binding activity of several
transcriptional factors involved in FasL expression, i.e., c-myc, NF-kappaB,
NF-ATp, and early growth factors (Egr) 2/3. The inhibition of NF-kappaB binding
is due to the stabilization of I-kappaB (inhibitory protein that dissociates
from NF-kappaB), through the inhibition of I-kappaB kinase alpha activity.
Subsequently, p65 nuclear translocation is significantly reduced. The inhibition
in NF-ATp binding results from a calcineurin-independent reduction in NF-ATp
nuclear translocation. VIP/PACAP inhibit the expression of Egr2 and 3, but not
of Egr1. The effects on the transcriptional factors are mediated through type 2
VIP receptor with cAMP as secondary messenger.

PMID: 11145682 [PubMed - indexed for MEDLINE]


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20: J Cell Biochem. 2000 Mar;77(2):323-32. 

ATP-stimulated c-fos and zif268 mRNA expression is inhibited by chemical hypoxia
in a rat brain-derived type 2 astrocyte cell line, RBA-2.

Hung AC, Huang HM, Tsay HJ, Lin TN, Kuo JS, Sun SH.

Institute of Neuroscience, National Yang Ming University, Taipei, Taiwan, ROC.

The stimulus-transcriptional coupling during ischemia/hypoxia was examined for
ATP-stimulated expression of immediate early genes (IEGs; c-fos, zif268, c-myc
and nur77) in a rat brain-derived type 2 astrocyte cell line, RBA-2. Incubation
of cells with 1 mM of extracellular ATP stimulated time-dependent expression of
c-fos and zif268. ATP induced the largest increases in zif268 mRNA and a lesser
one in c-fos mRNA. ATP also induced a slight increase in nur77 mRNA but was
ineffective in inducing c-myc expression in these cells. Brief exposure of cells
to potassium cyanide to simulate chemical hypoxia induced 9-fold and 7-fold
transient increases in c-fos and zif268 expression, respectively, but did not
affect c-myc or nur77 expression. When cyanide and ATP were added together, the
expression of c-fos and zif268 expression was inhibited, and the effect was
mimicked by simulating chemical hypoxia with sodium azide. To elucidate the
mechanism involved, the effect of cyanide on ATP-stimulated increases in
intracellular Ca(2+) concentrations, [Ca(2+)](i), and phospholipase D (PLD)
activities were measured. Cyanide induced an increase in [Ca(2&plus);](i) and
further enhanced the ATP-stimulated increases in [Ca(2+)](i) and PLD activities.
Nevertheless, metabolic inhibitor, iodoacetate, blocked the ATP-induced c-fos
and partially inhibited zif268 expression, and deprivation of cells with glucose
also inhibited the ATP-induced c-fos expression. Taken together, these results
demonstrate that both extracellular ATP and chemical hypoxia induce c-fos and
zif268 expression in RBA-2 type 2 astrocytes. The chemical hypoxia inhibited
ATP-stimulated c-fos and zif268 expression is not due to alterations in Ca(2+)
and PLD signaling, and is at least partially related to metabolic disturbance in
these cells. Copyright 2000 Wiley-Liss, Inc.

PMID: 10723097 [PubMed - indexed for MEDLINE]


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21: Food Chem Toxicol. 2000 Apr;38(4):339-49. 

Promotion of morphological transformation by Di-n-butyltin dichloride in
C3H/10T1/2 cells: prediction by prior expression of tumour promoter-responsive
genes.

Parfett CL, Marquardt T, Pilon R.

Mutagenesis Section, Environmental Health Directorate, Health Canada,
Environmental Health Centre, Tunney's Pasture, Ottawa, Ontario, Canada.
Craig_Parfett@hc-sc.gc.ca

Previous studies in our laboratory have shown that chemical treatments may
induce increases in proliferin gene family mRNA accumulation in cultured murine
embryonic cells. Proliferin inductions are highly correlated with subsequent
promotional outcomes during two-stage focus-formation assays in C3H/10T1/2 cell
cultures. In work reported here, the strong affiliation between these two
responses was further validated after treating cells with di-n-butyltin
dichloride which is a polyvinyl chloride (PVC) plastic additive that often
contaminates food and water. Increased proliferin expression and promotion of
morphological transformation occurred at similar concentrations. Promotion of
transformation was detected at di-n-butyltin dichloride concentrations of 80 nM
(24 ng/ml) and above, if added to initiated cultures before confluent monolayers
had formed. Proliferin induction and morphological transformation were both
reduced in confluent cultures treated with di-n-butyltin dichloride, as compared
to subconfluent cultures. Proliferin expression measured in near-confluent
cultures was induced up to 10-fold during the 36-hr period following
di-n-butyltin dichloride exposure and was accompanied by increased accumulation
of transcripts from many genes regulated by oxidative stresses, growth-inducing
agents, and/or other promoting agents (asbestos, superoxide radicals ).
Di-n-butyltin dichloride-induced mRNA species included members of the fos and
jun proto-oncogene families, c-myc, egr1, ribonucleotide reductase (R2 subunit),
odc, macrophage chemotactic protein/je, hsp70, metallothionine IIA, c-sod and
mn-sod. The observed patterns of RNA accumulation suggested that a small subset
of mRNA species, including proliferin, exhibit regulatory behaviour as a
response to dissimilar agents or conditions that promote focus-formation in
C3H/10T1/2 cultures. Plausible predictions of promotional effects in two-stage
morphological transformation assays can be made from gene-expression responses
to test agents.

PMID: 10722888 [PubMed - indexed for MEDLINE]


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22: FEBS Lett. 1999 Nov 12;461(1-2):37-42. 

Involvement of the NGFI-A gene in the differentiation of neuroblastoma cells.

Pignatelli M, Cortes-Canteli M, Santos A, Perez-Castillo A.

Instituto de Investigaciones Biomedicas, CSIC, Arturo Duperier, 4, 28029,
Madrid, Spain.

The transcription factor NGFI-A is an early response gene that has been
implicated in the regulation of cell growth and differentiation and, more
recently, in apoptosis. This gene is expressed in many tissues, and is very
abundant in the brain. However, little is known about its functional role in the
differentiation of this tissue. In the present work we investigated the role of
NGFI-A in serum withdrawal-induced differentiation in N2A neuroblastoma cells.
To do so, we studied the effect of NGFI-A antisense oligonucleotides and NGFI-A
overexpression on this process. We show that neuroblastoma cells treated with an
NGFI-A antisense oligonucleotide do not undergo normal morphological
differentiation after serum withdrawal, whereas N2A cells overexpressing this
gene extend long neurites, even in the presence of serum. We also show that
NGFI-A overexpression is accompanied by an increase in the amount of
phosphorylated microtubule-associated protein MAP1B, which has been associated
with neurite outgrowth. Our results suggest that the NGFI-A gene plays an
important role in neurite extension.

PMID: 10561492 [PubMed - indexed for MEDLINE]


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23: Clin Immunol. 1999 Nov;93(2):152-61. 

Curcumin causes the growth arrest and apoptosis of B cell lymphoma by
downregulation of egr-1, c-myc, bcl-XL, NF-kappa B, and p53.

Han SS, Chung ST, Robertson DA, Ranjan D, Bondada S.

Department of Microbiology and Immunology, Department of General Surgery,
Lexington, Kentucky 40536, USA.

It has been well known that curcumin is a powerful inhibitor of proliferation of
several tumor cells. However, the molecular basis of the anti-proliferative
effect of curcumin has not been investigated in detail. In this paper, we
present evidence to show that curcumin inhibited proliferation of a variety of B
lymphoma cells. At low concentrations curcumin inhibited the proliferation of
BKS-2, an immature B cell lymphoma, more effectively than that of normal B
lymphocytes and caused the apoptosis of BKS-2 cells in a dose- and
time-dependent manner. Furthermore, curcumin downregulated the expression of
survival genes egr-1, c-myc, and bcl-X(L) as well as the tumor suppressor gene
p53 in B cells. In addition, NF-kappaB binding activity was also downregulated
almost completely by curcumin. Stimulation with CpG oligonucleotides or
anti-CD40 overcame growth inhibition induced by low concentrations of curcumin.
Our results suggest that curcumin caused the growth arrest and apoptosis of
BKS-2 immature B cell lymphoma by downregulation of growth and survival
promoting genes. Copyright 1999 Academic Press.

PMID: 10527691 [PubMed - indexed for MEDLINE]


---------------------------------------------------------------


24: J Cell Physiol. 1999 Nov;181(2):342-54. 

Immediate early gene expression in dog thyrocytes in response to growth,
proliferation, and differentiation stimuli.

Deleu S, Pirson I, Clermont F, Nakamura T, Dumont JE, Maenhaut C.

Institute of Interdisciplinary Research, School of Medicine, University of
Brussels, Brussels, Belgium. sdeleu@ulb.ac.be

In dog thyroid cells, insulin or IGF-1 induces cell growth and is required for
the mitogenic action of TSH through cyclic AMP, of EGF, and of phorbol esters.
HGF per se stimulates cell proliferation and is thus the only full mitogenic
agent. TSH and cAMP enhance, whereas EGF phorbol esters and HGF repress
differentiation expression. In this study, we have investigated for each factor
and regulatory cascade of the intermediate step of immediate early gene
induction, that is, c-myc, c-jun, jun D, jun B, c-fos, fos B, fra-1, fra-2, and
egr1; fra-1 and fra-2 expressions were very low. TSH or forskolin increased the
levels of c-myc, jun B, jun D, c-fos, and fos B while decreasing those of c-jun
and egr1. Phorbol myristate ester stimulated the expression of all the genes.
EGF and HGF stimulated the expression of all the genes except jun D and for EGF
fos B. All these effects were obtained in the presence and in the absence of
insulin, which shows that insulin is not necessary for the effects of the
mitogens on immediate early gene expression. The definition of the repertoire of
early immediate genes inductible by the various growth cascades provides a
framework for the analysis of gene expression in tumors. (1) Insulin was able to
induce all the protooncogenes investigated except fos B. This suggests that fos
B could be the factor missing for insulin to induce mitogenesis. (2) No
characteristic pattern of immediate early gene expression has been observed for
insulin, which induces cell hypertrophy and is permissive for the action of the
other growth factors. These effects are therefore not accounted for by a
specific immediate early gene expression. On the other hand, insulin clearly
enhances the effects of TSH, phorbol ester, and EGF on c-myc, junB, and c-fos
expression. This suggests that the effect of insulin on mitogenesis might result
from quantitative differences in the transcription complexes formed. (3) c-myc,
c-fos, and jun B mRNA induction by all stimulating agents, whether inducing cell
hypertrophy, or growth and dedifferentiation, or growth and differentiation,
suggests that, although these expressions are not sufficient, they may be
necessary for the various growth responses of thyroid cells. (4) The inhibition
of c-jun and egr1 mRNA expression, and the marked induction of jun D mRNA appear
to be specific features of the TSH cAMP pathway. They might be related to its
differentiating action. (5) fos B, which is induced by TSH, forskolin, phorbol
ester, and HGF but not by insulin, could be involved in the mitogenic action of
the former factors. Copyright 1999 Wiley-Liss, Inc.

PMID: 10497313 [PubMed - indexed for MEDLINE]


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25: J Am Soc Nephrol. 1999 Sep;10(9):1891-9. 

High glucose stimulates proliferation and collagen type I synthesis in renal
cortical fibroblasts: mediation by autocrine activation of TGF-beta.

Han DC, Isono M, Hoffman BB, Ziyadeh FN.

Penn Center for Molecular Studies of Kidney Diseases, Department of Medicine,
University of Pennsylvania, Philadelphia 19104-6144, USA.

Renal tubular epithelial cells and interstitial fibroblasts are active
participants in tubulointerstitial fibrosis, the best correlate of decreased
glomerular filtration in diabetic nephropathy. It was reported previously that
high ambient glucose stimulates transforming growth factor-beta (TGF-beta) mRNA
and bioactivity, promotes cellular hypertrophy, and increases collagen synthesis
in proximal tubular cells. This study evaluates the effects of high glucose and
TGF-beta on the behavior of murine renal cortical fibroblasts (TFB) in culture.
High glucose (450 mg/dl) significantly increased [3H]-thymidine incorporation
(by 60 to 80% after 24 to 72 h) and cell number, without significantly
increasing cell death when compared with normal glucose (100 mg/dl). There also
was a transient increase in the mRNA of the c-myc and egr-1 early-response
genes. Exogenous TGF-beta1 was promitogenic rather than antiproliferative in
contrast to other renal cell types. Northern blot analysis demonstrated
constitutive expression of TGF-beta1, -beta2, and -beta3 transcripts. Exposure
to high glucose increased all three TGF-beta isoforms in a time-dependent
manner. High glucose as well as exogenous TGF-beta1 also increased [3H]-proline
incorporation, alpha2(I) collagen mRNA, and type I collagen protein (measured by
immunoassay). Treatment with a neutralizing pan-selective monoclonal
anti-TGF-beta antibody markedly attenuated the stimulation by high ambient
glucose of thymidine incorporation, TGF-beta1 mRNA, and type I collagen mRNA and
protein levels. It is concluded that high ambient glucose and exogenous
TGF-beta1 share similar actions on renal fibroblasts. Moreover, the stimulation
of cell proliferation and collagen type I synthesis in these cells by high
ambient glucose are mediated by activation of an autocrine TGF-beta system.

PMID: 10477140 [PubMed - indexed for MEDLINE]


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26: Int Immunol. 1999 Jun;11(6):871-9. 

CpG oligodeoxynucleotides rescue BKS-2 immature B cell lymphoma from
anti-IgM-mediated growth inhibition by up-regulation of egr-1.

Han SS, Chung ST, Robertson DA, Chelvarajan RL, Bondada S.

Department of Microbiology and Immunology, and Sanders-Brown Research Center on
Aging, University of Kentucky, Lexington, KY 40536, USA.

Cross-linking of the IgM antigen receptor on an immature B cell lymphoma (BKS-2)
induces growth arrest and apoptosis. This is accompanied by down-regulation of
the immediate early genes, egr-1 and c-myc, and a reduction in NF-kappaB
activity. Anti-IgM-induced growth arrest and apoptosis of this murine B cell
lymphoma were prevented by oligodeoxynucleotides (ODN) containing the CpG motif,
which are also known to be stimulatory for mature and immature B cells. The CpG
but not non-CpG ODN rescued BKS-2 cells from anti-IgM-mediated growth inhibition
by up-regulation of egr-1 and c-myc expression as well as by restoring NF-kappaB
activity. Interestingly, changes in egr-1 expression occurred more rapidly than
in c-myc expression. Also the c-myc levels remained high up to 6 h after
addition of the anti-IgM, which was also the time until which the addition of
CpG could be delayed without affecting its ability to provide complete
protection. This CpG-induced rescue of B lymphoma cells was blocked by antisense
egr-1 ODN, suggesting that the expression of egr-1 is important for the effects
of CpG ODN on the growth and survival of BKS-2 cells.

PMID: 10360960 [PubMed - indexed for MEDLINE]


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27: 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]


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28: Am J Physiol. 1997 Dec;273(6 Pt 2):H2678-86. 

BNP gene expression is specifically modulated by stretch and ET-1 in a new model
of isolated rat atria.

Bruneau BG, Piazza LA, de Bold AJ.

University of Ottawa Heart Institute, Ottawa Civic Hospital, Ontario, Canada.

We have assessed the effects of stretch or endothelin-1 (ET-1) on atrial
natriuretic factor (ANF) and brain natriuretic peptide (BNP) secretion and gene
expression using a new model of isolated right atria from the rat. This model
allows for comparatively long-term in vitro study of adult tissue while
retaining the anatomic conformation of the atrium. Stretch and ET-1 resulted in
a transient stimulation of ANF and BNP secretion, with an initially larger
proportional increase in ANF release. Stretch and ET-1 induced a marked increase
in BNP gene expression after 1.5 and 4 h, respectively; the increase in BNP mRNA
levels was maintained throughout the 8-h experimental period. Stretch and ET-1
also stimulated c-myc and Egr-1 mRNA levels, two markers of mechanical and
receptor-mediated transcriptional activation. The selective response of BNP gene
to stretch and ET-1 and the distinct responses of ANF and BNP secretion indicate
that the atrial cardiocytes have the capability to individually regulate the
synthesis of its endocrine products. This suggests that each hormone plays a
specific role in the response of the heart to hemodynamic or neuroendocrine
imbalances.

PMID: 9435604 [PubMed - indexed for MEDLINE]


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29: Pflugers Arch. 1997 Sep;434(5):568-74. 

In vivo carbon monoxide exposure and hypoxic hypoxia stimulate immediate early
gene expression.

Gess B, Wolf K, Pfeifer M, Riegger GA, Kurtz A.

Institut fur Physiologie, Universitat Regensburg, Germany.

This study aimed to examine the influence of acute tissue hypoxygenation on the
expression of immediate early genes in different rat tissues. To this end male
Sprague-Dawley rats were exposed to 0.1% carbon monoxide for 0.5, 1 and 6 h or
to 9% oxygen for 6 h and mRNA levels for c-jun, c-fos, c-myc and EGR-1 were
assayed by RNase protection in hearts, kidneys, livers and lungs. We found that
hypoxia increased c-jun mRNA levels between twofold (lung) and eightfold (liver)
in all organs examined; c-fos mRNA increased between three-fold (lung) and
20-fold (heart); c-myc mRNA increased between twofold (lung) and sixfold
(heart); and EGR-1 mRNA increased between twofold (lung) and sixfold (heart).
Our findings suggest that acute tissue hypoxygenation is a general stimulus of
the expression of immediate early genes in vivo. With regard to the sensitivity
to hypoxia, organ differences appear to exist in that the lung is rather
insensitive, whilst the heart is rather sensitive.

PMID: 9242720 [PubMed - indexed for MEDLINE]


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30: Blood. 1997 Feb 15;89(4):1197-206. 

Characterization of cis-acting sequences and trans-acting signals regulating
early growth response 1 and c-fos promoters through the granulocyte-macrophage
colony-stimulating factor receptor in BA/F3 cells.

Watanabe S, Kubota H, Sakamoto KM, Arai K.

Department of Molecular and Developmental Biology, Institute of Medical Science,
The University of Tokyo, Japan.

Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) activates a set
of genes such as c-fos, jun, myc, and early growth response gene 1 (egr-1).
Studies on BA/F3 cells that express hGM-CSF receptor (hGMR) showed that two
different signaling pathways controlled by distinct regions within the beta
subunit are involved in activation of c-fos/c-jun genes and in c-myc,
respectively. However, the region(s) of the beta subunit responsible for
activation of the egr-1 gene and other regulatory genes has not been identified.
We describe here how egr-1 promoter is activated by hGMR through two regions of
the beta subunit, with these regions being required for activation of the c-fos
promoter. Coexpression of dominant negative (dn) Ras (N17ras) or dn JAK2 almost
completely suppressed the activation of egr-1 and c-fos promoters. Deletion
analysis of egr-1 promoter showed two cis-acting regions responsible for
activation by hGM-CSF or mouse interleukin-3 (mIL-3), one between nucleotide
positions (nt) -56 and -116, and the other between nt -235 and -480, which
contains tandem repeats of the serum response element (SRE) sites. Similar
experiments with the c-fos promoter showed that cis-acting regions containing
the SRE/AP-1 sites is sufficient for activation by hGM-CSF. Based on these
observations, we propose that signaling pathways activating egr-1 and c-fos
promoters are controlled by SRE elements, either through the same or overlapping
pathways that involve JAK2 and Ras.

PMID: 9028942 [PubMed - indexed for MEDLINE]


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31: 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]


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32: Mol Cell Biol. 1996 May;16(5):2283-94. 

Role of EGR1 in regulation of stimulus-dependent CD44 transcription in B
lymphocytes.

Maltzman JS, Carman JA, Monroe JG.

Department of Pathology and Laboratory Medicine, University of Pennsylvania,
School of Medicine, Philadelphia, 19104, USA.

The immediate-early gene egr-1 encodes a transcription factor (EGR1) that links
B-cell antigen receptor (BCR) signals to downstream activation events through
the regulation of previously unidentified target genes. Here we identify the
gene encoding the lymphocyte homing and migration protein CD44 as a target of
EGR1 regulation in B cells. BCR-induced increases in CD44 mRNA expression and
transcription levels are shown to occur in EGR1-expressing but not in
nonexpressing subclones of the B-cell line WEHI-231. Kinetics of egr-1
transcription and the appearance of nuclear EGR1 protein precede CD44 induction
and occur within 30 min after stimulation in the EGR1-expressing subclone. A
single EGR1 binding motif is demonstrated at bp -301 of the human CD44 promoter.
Cotransfection of a CD44 promoter-chloramphenicol acetyltransferase reporter
construct with an egr-1 expression vector resulted in a 6.5- to 8.5-fold
induction of transcriptional activity relative to an empty expression vector.
The EGR1 binding motif was shown to be necessary for stimulus-induced expression
of a CD44 promoter-chloramphenicol acetyltransferase reporter construct in
nontransformed B lymphocytes and was required for transactivation by an EGR1
expression vector in a B-cell line. These studies identify EGR1 as an
intermediary linking BCR-derived signals to the induction of CD44. The relevance
of these molecular events to BCR signal transduction and antigen-stimulated
B-cell-mediated immune responses is discussed.

PMID: 8628295 [PubMed - indexed for MEDLINE]


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33: Endocrinology. 1996 Jan;137(1):137-43. 

Alpha 1-adrenergic stimulation of isolated rat atria results in discoordinate
increases in natriuretic peptide secretion and gene expression and enhances
Egr-1 and c-Myc expression.

Bruneau BG, Piazza LA, de Bold AJ.

University of Ottawa Heart Institute Research Center, Ottawa Civic Hospital,
Ontario, Canada.

We studied the effects of alpha1-adrenergic stimulation on atrial natriuretic
factor (ANF) and brain natriuretic peptide (BNP) secretion and gene expression
in isolated right atria. The early-response genes Egr-1 and c-myc were also
studied as potential markers of transcriptional activation after
alpha1-adrenergic stimulation. Isolated right atria from rats were stimulated
for up to 8 h by the alpha1-adrenergic agonist phenylephrine (PE). PE at 10, 50,
or 100 microM stimulated the secretion of immunoreactive (ir) ANF, beginning at
0.5 h and peaking after 1.5 h, IrANF secretion remained significantly elevated
for 8 h with 100 microM PE, reached control levels after 5 h with 10 microM PE,
and after 6 h microM PE with 50 microM PE, PE at 50 or 100 microM stimulated
irBNP secretion after 15 min, which peaked at 1 h, and thereafter remained above
control levels. Calculation of irANF/irBNP ratios revealed that their stimulated
secretion was not coregulated. PE caused significant changes in steady state
transcript levels for the genes studied. After 6 h, 50 microM PE caused a 49%
increase in ANF messenger RNA (mRNA) levels. BNP mRNA levels were increased by
135% after 6 h and by 77% after 8 h. Egr-1 mRNA levels were increased by 81%
after 4 h, 167 after 6 h, and 40% after 8 h of treatment, mRNA levels of c-myc
were increased by 49% after 4 h and 53% after 6 h. PE-induced increases in
secretion and gene expression were inhibited by the alpha1-adrenergic receptor
antagonist prozosin (10 microM). We conclude that both ANF and BNP secretion
from atria can be stimulated by PE, and that their secretion is not coregulated.
The kinetics of enhanced natriuretic peptide gene expression and secretion did
not change in parallel, suggesting that these processes are not acutely
coordinated. The enhanced expression of Egr-1 and c-myc suggests that they may
be involved in the modulation of atrial gene expression in response to
alpha1-adrenergic stimulation. The results presented suggest that compensatory
adrenergic activation such as those seen in several clinical entities may be one
of the factors that provide long-term enhanced natriuretic peptide production,
thus contributing to the maintenance of cardiovascular homeostasis.

PMID: 8536605 [PubMed - indexed for MEDLINE]


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34: J Pediatr Gastroenterol Nutr. 1995 Aug;21(2):158-64. 

Early proliferative events following intestinal resection in the rat.

Sacks AI, Warwick GJ, Barnard JA.

Department of Pediatrics, Vanderbilt University School of Medicine, Nashville,
Tennessee 37232-2576, USA.

Partial resection of the small intestine results in compensatory proliferation
and adaptation in the remaining small intestinal mucosa. The molecular
mechanisms governing the proliferative response are not known, nor has the
timing of events associated with proliferation been adequately defined,
particularly during the period just after resection. We designed experiments to
characterize early (within 24 h) proliferative events associated with proximal
intestinal resection and sought to determine the cell type that first responds
to proliferative stimuli. Twenty-one day old male Sprague-Dawley rats underwent
a 70% proximal intestinal resection or transection (control). Poly(A) RNA was
isolated from the distal (ileal) remnants. Northern blots showed a marked
induction of the immediate early genes zif-268, nup-475, and c-myc 1-3 h
following resection, but not following transection. Immunohistochemical analysis
of c-myc expression in ileal crypt epithelial cells showed a biphasic induction
that was most marked 6 h after resection and less prominent 24 h after
resection. Immunostaining with 5-bromodeoxyuridine (5-BrdU) was restricted to
ileal crypt nuclei and was maximal 24 h after resection. All these events were
observed in the absence of nutrient intake. Taken together, these data show that
a potent nutrient-independent stimulus for intestinal epithelial cell
proliferation occurs within minutes of partial small intestinal resection and
that the first targets of this stimulus are crypt epithelial cells in the
residual intestine.

PMID: 7472902 [PubMed - indexed for MEDLINE]


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35: Cell Immunol. 1995 May;162(2):309-14. 

Constitutive and inducible levels of egr-1 and c-myc early growth response gene
expression in self-renewing B-1 lymphocytes.

Wang Z, Morris DL, Rothstein TL.

Department of Medicine, Boston University Medical Center, Massachusetts 02118,
USA.

B-1 lymphocytes constitute a mature B cell population that differs from
conventional B cells in signaling requirements for cell cycle progression, being
unusually responsive to PKC agonism but refractory to antigen receptor
stimulation. Further, B-1 cells are self-renewing and derive from surface
immunoglobulin-positive precursors. A previous report on clonally derived B-1
cells suggested that increased levels of expression of c-myc might underlie
these unusual growth characteristics. This issue has now been reexamined using
primary B-1 cells. The possible role of egr-1, in addition to c-myc, in
specifying the responsiveness of B-1 cells was evaluated by determining levels
of gene expression at baseline and after mitogenic treatment. Expression of the
two genes was similar in B-1 and B-2 cells prior to stimulation. Subsequently,
B-1 cells responded with higher levels of gene expression than B-2 cells
regardless of ultimate cell cycle progression, with the exception of stimulation
by anti-Ig. Overall, there was no apparent direct correlation between stimulated
levels of expression of egr-1 or c-myc and mitogen-induced S phase entry, nor
were B-1 cells characterized by constitutively elevated levels of either
proto-oncogene that might explain their capacity for self-renewal.

PMID: 7743559 [PubMed - indexed for MEDLINE]


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36: Cardiovasc Res. 1994 Oct;28(10):1519-25. 

Selective changes in natriuretic peptide and early response gene expression in
isolated rat atria following stimulation by stretch or endothelin-1.

Bruneau BG, de Bold AJ.

University of Ottawa Heart Institute, Ottawa Civic Hospital, Ontario, Canada.

OBJECTIVE: Important physiological and pathophysiological conditions are
associated with changes in secretion and synthesis of atrial natriuretic factor
(ANF) and brain natriuretic peptide (BNP). The aim of this study was to examine
the effects of mechanical stretch and endothelin-1 on ANF and BNP secretion and
gene expression in isolated adult rat atria, as paradigms for mechanical and
endocrine stimulation of atrial tissue. The expression of the early response
genes c-fos, c-jun, Egr-1, and c-myc was also studied, since their protein
products may be involved in controlling natriuretic peptide gene expression.
METHODS: Isolated rat atria were stimulated by stretch (5 g) or endothelin-1
(10(-7) M) for 30 min, 2 h, or 4 h. ANF and BNP secretion was measured by
radioimmunoassay, and relative mRNA levels were determined by northern blotting.
RESULTS: Atrial stretch resulted in an immediate 1.8-fold increase in ANF
release, which returned to basal levels after 160 min. Endothelin-1 caused a
gradual increase in ANF release, up to 2.3 times basal levels, and thereafter
returned towards basal levels. BNP secretion was increased threefold by
endothelin-1, and remained significantly raised for 90 min. BNP mRNA levels were
transiently increased by 33% after 2 h of endothelin-1 stimulation. Stretch
increased c-fos mRNA levels (+55%) and Egr-1 mRNA levels (+70%) after 2 h, and
increased c-myc mRNA levels (+69%) after 4 h. Endothelin-1 increased Egr-1 mRNA
levels up to +767% after 4 h. CONCLUSIONS: Endothelin-1 stimulates BNP secretion
from rat atria; this is followed by an increase in BNP mRNA levels. Conversely,
acute secretion of ANF by stretch or endothelin-1 is not accompanied by changes
in ANF mRNA levels. Atrial stretch results in changes in the expression of the
early response genes c-fos, Egr-1, and c-myc, while endothelin-1 stimulates
Egr-1 expression. The specific changes in natriuretic peptide and early response
gene expression reveal distinct mechanisms of modulation of atrial gene
expression by mechanical and endocrine stimuli.

PMID: 8001040 [PubMed - indexed for MEDLINE]


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37: 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]


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38: J Biol Chem. 1994 Jun 10;269(23):16137-42. 

Platelet-derived growth factor (PDGF) induction of egr-1 is independent of PDGF
receptor autophosphorylation on tyrosine.

Mundschau LJ, Forman LW, Weng H, Faller DV.

Boston University School of Medicine, Cancer Research Center, Massachusetts
02118.

Autophosphorylation of the platelet-derived growth factor (PDGF) receptor on
tyrosine, which is dependent upon and occurs immediately after ligand binding,
has been linked to the activation of second messenger pathways thought to be
necessary for the induction of gene expression, DNA synthesis, and mitogenesis.
We have investigated PDGF signal transduction in Balb/c3T3 and NIH-3T3 cells at
the level of immediate-early gene induction under three conditions in which PDGF
receptor autophosphorylation in response to PDGF binding is blocked: cells
transformed by v-rasKi, cells transformed by v-mos, and cells treated with
genistein, a specific inhibitor of tyrosine kinases. PDGF induction of
immediate-early genes c-myc, c-fos, and JE is blocked in these systems.
Induction of another immediate-early gene, egr-1, occurs normally despite the
absence of measurable tyrosine kinase activity. The same results were obtained
when cells were stimulated with PDGF-AA or PDGF-BB. It is not yet clear if this
receptor tyrosine kinase-independent signal utilizes known PDGF second
messengers, but these results demonstrate a new arm of the PDGF signal
transduction pathway which operates in the absence of, and independently from,
autophosphorylation of the receptor on tyrosine.

PMID: 8206913 [PubMed - indexed for MEDLINE]


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39: FEBS Lett. 1993 Mar 22;319(3):221-4. 

The induction of early response genes in rat smooth muscle cells by PDGF-AA is
not sufficient to stimulate DNA-synthesis.

Sachinidis A, Schulte K, Ko Y, Meyer zu Brickwedde MK, Hoppe V, Hoppe J, Vetter
H.

Medizinische Universitats-Poliklinik, Bonn, Germany.

The effect of the three platelet-derived growth factor (PDGF) isoforms AA, AB
and BB on the induction of the early growth response genes c-fos, egr-1 and
c-myc mRNA in vascular smooth muscle cells from rat was compared with their
respective mitogenic potency. The three PDGF isoforms strongly stimulated the
induction to a similar extent. In contrast, PDGF-AB and -BB provoked a marked
DNA synthesis whereas PDGF-AA exerted only a poor mitogenic effect in smooth
muscle cells. PDGF-AA-stimulated receptor autophosphorylation was not detectable
in comparison with the strong effect elicited by PDGF-AB or -BB and correlated
with its low mitogenicity but not with the almost equal induction of the early
response genes. It is discussed that no or only very low receptor
phosphorylation is required to link receptor activation to the induction of
c-fos, egr-1 or c-myc. Furthermore the induction of the investigated gene does
not seem to be sufficient for an optimal mitogenic response.

PMID: 7681410 [PubMed - indexed for MEDLINE]


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40: Proc Natl Acad Sci U S A. 1992 Oct 15;89(20):9905-9. 

Roles of mechano-sensitive ion channels, cytoskeleton, and contractile activity
in stretch-induced immediate-early gene expression and hypertrophy of cardiac
myocytes.

Sadoshima J, Takahashi T, Jahn L, Izumo S.

Indursky Laboratory of Molecular Cardiology, Beth Israel Hospital, Boston, MA
02215.

Mechanical loading of cardiac and skeletal muscles in vivo and in vitro causes
rapid activation of a number of immediate-early (IE) genes and hypertrophy of
muscle cells. However, little is known as to how muscle cells sense mechanical
load and transduce it into intracellular signals of gene regulation. We examined
roles of putative cellular mechanotransducers, mechanosensitive ion channels,
the cytoskeleton, and contractile activity in stretch-induced hypertrophy of
cardiac myocytes grown on a deformable silicone sheet. Using the patch-clamp
technique, we found a single class of stretch-activated cation channel that was
completely blocked by gadolinium (Gd3+). Inhibition of this channel by Gd3+ did
not affect either the stretch-induced expression of IE genes or the increase in
protein synthesis. Neither disruption of microtubules with colchicine nor that
of actin microfilaments by cytochalasin D prevented the stretch-induced IE gene
expression and increase in protein synthesis. Arresting contractile activity of
myocytes by high K+, tetrodotoxin, or Ba2+ did not affect the stretch-induced IE
gene expression. Tetrodotoxin-arrested myocytes could increase protein synthesis
in response to stretch. These results suggest that Gd(3+)-sensitive ion
channels, microtubules, microfilaments, and contractile activity may not be
necessary for transduction of mechanical stretch into the IE gene expression and
hypertrophy. The stimulus of membrane stretch may be transmitted to the cell
nucleus through some mechanisms other than electrical or direct mechanical
transduction in cardiac myocytes.

PMID: 1384064 [PubMed - indexed for MEDLINE]


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41: J Immunol. 1992 Sep 15;149(6):1867-75. 

Inducible cell contact signals regulate early activation gene expression during
B-T lymphocyte collaboration.

Klaus SJ, Parker DC.

Department of Molecular Genetics and Microbiology, University of Massachusetts
Medical Center, Worcester 01655.

B cells get help in the antibody response by presenting processed Ag to Th
cells. We asked whether the Ag-presenting B cell must induce Th functions before
receiving help, or whether B cell activation is a direct consequence of T cell
recognition of Ag on the B cell surface. To obtain a prompt and sensitive
indication of the receipt of growth signals, we measured mRNA levels of the
immediate early genes, c-myc and egr-1, in T and B cells separated from
Ag-specific B-T conjugates of normal, resting murine B cells and a Th line.
Although Ag-dependent increases in B cell c-myc expression occur as early as 2 h
after conjugation, early c-myc expression in the B cell was also seen when the
Th cells were activated with immobilized anti-CD3 in the absence of Ag
recognition. Therefore, T cell activation rather than Ag recognition per se
appears to be responsible for the early c-myc signal in the B cells. The c-myc
response in the B cell depends on induction of a contact-dependent helper
function in the T cell, which is inhibitable by cyclosporin A acting on the T
cell. Delivery of contact help is not blocked by anti-class II MHC antibody.
Contact with activated Th cells induces a different pattern of immediate early
gene expression from that induced by cross-linking the B cell Ag receptor.

PMID: 1387663 [PubMed - indexed for MEDLINE]


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42: Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5437-41. 

Brief visual experience induces immediate early gene expression in the cat
visual cortex.

Rosen KM, McCormack MA, Villa-Komaroff L, Mower GD.

Massachusetts General Hospital, Department of Neurobiology, Harvard Medical
School, Boston 02129.

Brief visual experience causes rapid physiological changes in the visual cortex
during early postnatal development. A possible mediator of these effects is the
immediate early genes whose protein products are involved in the rapid response
of neurons to transsynaptic stimulation. Here we report evidence that the levels
of immediate early gene mRNAs in the visual cortex can be altered by
manipulating the visual environment. Specifically, we find that brief (1 h)
visual experience in dark-reared cats causes dramatic transient inductions of
egr1, c-fos, and junB mRNAs in the visual cortex but not in the frontal cortex.
Levels of c-jun and c-myc mRNAs are unaffected. These results suggest that
select combinatorial interactions of immediate early gene proteins are an
important step in the cascade of events through which visually elicited activity
controls visual cortical development.

PMID: 1376920 [PubMed - indexed for MEDLINE]


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43: J Biol Chem. 1991 Jul 15;266(20):12813-6. 

Egr-1, a serum-inducible zinc finger protein, regulates transcription of the rat
cardiac alpha-myosin heavy chain gene.

Gupta MP, Gupta M, Zak R, Sukhatme VP.

Department of Medicine, University of Chicago, Illinois 60637.

Egr-1 is an early growth response gene that encodes a protein with three zinc
fingers and is involved in transcriptional regulation. In adult heart myocytes,
in contrast to c-fos and c-myc, high levels of Egr-1 mRNA expression have been
shown. Here we report that Egr-1 transactivates rat cardiac alpha-MHC gene
expression. In serum-starved primary cultures of 18-day-old fetal rat heart
myocytes, addition of serum evoked expression of both Egr-1 and alpha-MHC gene
transcripts. Inclusion of 10 microM cycloheximide in these cultures for 48 h
caused a greater increase in Egr-1 mRNA, whereas the expression of alpha-MHC
transcripts was ablated. To examine the involvement of Egr-1 in alpha-MHC
induction, we transfected primary cultures of cardiac myocytes with plasmids
pCMVEgr-1 (Egr-1 expression vector) and pMP3.3CAT containing -2.9- to
+0.42-kilobase sequences of the alpha-MHC gene fused to the coding region of the
chloramphenicol acetyltransferase (CAT) gene. Cotransfection of pCMVEgr-1
stimulated expression of pMP3.3CAT 10-15-fold. Furthermore, pCMVEgr-1 also
stimulated expression of the endogenous alpha-MHC gene in primary cultures of
cardiac myocytes. Transactivation of pMP3.3CAT expression by pCMVEgr-1 was also
observed by transfecting the myogenic cell line Sol 8, but not in L6E9 cells or
in NIH3T3 fibroblasts. By creating progressive 5' deletions of the alpha-MHC
gene, we found that the region extending between -1698 and -1283 base pairs is
necessary for Egr-1-induced expression of the alpha-MHC/CAT construct. These
results define a physiological target for the Egr-1 transcription factor and
delineate a novel mechanism for regulation of the alpha-MHC gene.

PMID: 2071571 [PubMed - indexed for MEDLINE]


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44: Mol Endocrinol. 1991 Jun;5(6):829-35. 

In vivo regulation of Zif268 messenger RNA expression by 17 beta-estradiol in
the rat uterus.

Suva LJ, Harm SC, Gardner RM, Thiede MA.

Department of Bone Biology and Osteoporosis Research Merck, Sharp, and Dohme
Research Laboratories, West Point, Pennsylvania 19486.

Administration of 17 beta-estradiol (E2) induces a mitogenic response in the rat
uterus. Previous studies have shown that this effect involves the transient
activation of c-fos and c-myc expression, followed by significant increases in
both DNA synthesis and cell proliferation. Zif268 is a zinc finger-containing,
DNA-binding transcription factor that has been implicated in the regulation of
cell growth and development and has been shown to be coregulated with c-fos in a
number of systems. To determine whether Zif268 is also a target for estrogen
regulation, we measured the effects of E2 on Zif268 mRNA expression in the
uterus of the ovariectomized rat. In this report we demonstrate that although
low levels of Zif268 mRNA expression are detectable in the uteri from
ovariectomized control rats, treatment with E2 (4, 40, or 400 micrograms/kg BW)
induces a rapid and transient 45- to 50-fold increase in the level of Zif268
mRNA 2 h after E2 treatment. The elevated levels of Zif268 mRNA returned to
basal 6 h after hormone treatment. Lower doses of E2 (0.004, 0.04, and 0.4
micrograms/kg) had little or no effect on Zif268 mRNA expression, while higher
doses of E2 (4-400 micrograms/kg) resulted in maximal increases in Zif268
expression. Dexamethasone, 5 alpha-dihydrotestosterone, and progesterone had no
effect on uterine Zif268 mRNA expression, and the induction of Zif268 by E2 was
abolished by pretreating the animals with the RNA synthesis inhibitor
actinomycin-D. In addition, stimulation of Zif268 mRNA expression was observed
with the short-acting estrogen estriol, suggesting that the response may be
specific for estrogenic steroids.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 1717835 [PubMed - indexed for MEDLINE]


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45: Oncogene Res. 1991;6(1):1-12. 

Interleukin-3 and phorbol esters induce different patterns of immediate-early
gene expression in an interleukin-3 dependent cell line.

McCubrey JA, Steelman LS, McKearn JP.

Department of Microbiology & Immunology, East Carolina University School of
Medicine, Greenville, North Carolina 27858.

The myeloid interleukin-3 (IL-3) dependent cell line, FDC-P1, enters the G0
stage of the cell cycle after IL-3 deprivation for 24 hr. The expression of 13
protooncogenes and immediate-early genes was compared with 4 "control" genes
after the addition of either IL-3 or phorbol myristate acetate (PMA) to
IL-3-deprived cells. mRNA transcripts encoding c-myc and the T-cell receptor
c-gamma gene were induced to high levels only after IL-3 addition, whereas
c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 were induced transiently only
after PMA addition. The remaining genes (fra-1, p53, jun-D, c-Ha-ras, c-Ki-ras,
c-raf, beta-actin, ornithine decarboxylase, and histone 2B) were detected after
culture with either IL-3 or PMA. When cells were serum- and IL-3-deprived,
c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 were detected after exposure to
either serum or PMA. Moreover, culture with cycloheximide and PMA resulted in
superinduction of these genes, whereas cycloheximide and IL-3 addition did not.
mRNAs encoding these genes had half-lives of 10-20 min after PMA treatment,
whereas that of beta-actin was longer (greater than 2 hr), suggesting that short
mRNA half-lives contributed to the transient nature of these genes. Although
c-fos, fos-B, c-jun, jun-B, Krox-20, and Krox-24 expression can be detected in
IL-3-dependent cells after exposure to either PMA or serum, these genes were not
detected after IL-3 addition, which allows cell-cycle progression. These results
document the existence of IL-3 and PMA-responsive genes and demonstrate that
IL-3 and protein kinase C agonists can induce distinct patterns of gene
expression.

PMID: 1705318 [PubMed - indexed for MEDLINE]


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