scholarly journals Trans-repressor activity of nuclear glycosaminoglycans on Fos and Jun/AP-1 oncoprotein-mediated transcription.

1992 ◽  
Vol 116 (1) ◽  
pp. 31-42 ◽  
Author(s):  
S J Busch ◽  
G A Martin ◽  
R L Barnhart ◽  
M Mano ◽  
A D Cardin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Enhanced Recovery ◽  
Present Report ◽  
Binding Activity ◽  
Heparin Binding ◽  
Dna Binding Activity ◽  
Cycle Arrest ◽  
Specific Mrnas ◽  
F9 Teratocarcinoma

Heparin blocks the phorbol ester-induced progression of nontransformed cells through the G0/G1 phase (Wright, T.C., L.A. Pukac, J.J. Castellot, M.J. Karnovsky, R.A. Levine, H.-Y. Kim-Park, and J. Campisi. 1989. Proc. Natl. Acad. Sci. USA. 86: 3199-3203) or G1 to S phase (Reilly, C. F., M. S. Kindy, K. E. Brown, R. D. Rosenberg, and G. E Sonenshein. 1989. J. Biol. Chem. 264:6990-6995) of the cell cycle. Cell cycle arrest was associated with decreased levels of stage-specific mRNAs suggesting transcriptional regulation of cell growth. In the present report, we show that heparin selectively repressed TPA-inducible AP-1-mediated gene expression. Heparin-induced trans-repression was observed in primary vascular smooth muscle cells, as well as in the transformed HeLa cell line and in nondifferentiated F9 teratocarcinoma cells. Inhibition of AP-1-mediated trans-activation occurred with heparin and pentosan polysulfate but not with chondroitin sulfate A or C. Heparin-binding peptides or heparitinase I addition to nuclear lysates of heparin-treated cells allowed enhanced recovery of endogenous AP-1-specific DNA binding activity. We propose a model in which nuclear glycosaminoglycans play a trans-regulatory role in altering the patterns of inducible gene expression.

Rb regulates C/EBPβ-DNA-binding activity during 3T3-L1 adipogenesis

2004 ◽  
Vol 286 (2) ◽  
pp. C349-C354 ◽  
Author(s):  
Kathryn A. Cole ◽  
Anne W. Harmon ◽  
Joyce B. Harp ◽  
Yashomati M. Patel
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Cell Cycle Arrest ◽  
Transcriptional Activation ◽  
Binding Activity ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Dna Binding Activity ◽  
Cycle Arrest ◽  
Rb Phosphorylation

Two pathways are initiated upon 3T3-L1 preadipocyte differentiation: the reentry of cells into the cell cycle and the initiation of a cascade of transcriptional events that “prime” the cell for differentiation. The “priming” event involves the synthesis of members of the CCAAT/enhancer binding protein (C/EBP) family of transcription factors. However, the relationship between these two pathways is unknown. Here we report that in the 3T3-L1 preadipocytes induced to differentiate, cell cycle progression and the initiation of differentiation are linked by a cell cycle-dependent Rb-C/EBPβ interaction. Cell cycle arrest in G1 by l-mimosine inhibited differentiation-induced C/EBPβ-DNA-binding activity and Rb phosphorylation. However, cell cycle arrest after the G1/S transition by aphidicolin or nocodazole did not prevent C/EBPβ-DNA-binding activity or Rb phosphorylation. Furthermore, hypophosphorylated Rb and C/EBPβ coimmunoprecipitated, whereas phosphorylated Rb and C/EBPβ did not. Electrophoretic mobility shift assays demonstrated that recombinant hypophosphorylated Rb decreased C/EBPβ-DNA-binding activity and that Rb overexpression inhibited C/EBPβ-induced transcriptional activation of a C/EBPα-promoter-luciferase reporter gene. We conclude that C/EBPβ-DNA-binding activity is regulated by its interaction with hypophosphorylated Rb, thereby linking the progression of the cell cycle to the initiation of differentiation during 3T3-L1 adipogenesis.

scholarly journals E2F1 sumoylation as a protective cellular mechanism in oxidative stress response

2020 ◽  
Vol 117 (26) ◽  
pp. 14958-14969 ◽  
Author(s):  
Joshua D. Graves ◽  
Yu-Ju Lee ◽  
Kang Liu ◽  
Gang Li ◽  
Fang-Tsyr Lin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Transcriptional Activity ◽  
Tumor Grade ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Cycle Arrest ◽  
A Cell ◽  
Oxidative Insult

Oxidative stress is a ubiquitous threat to all aerobic organisms and has been implicated in numerous pathological conditions such as cancer. Here we demonstrate a pivotal role for E2F1, a cell cycle regulatory transcription factor, in cell tolerance of oxidative stress. Cells lacking E2F1 are hypersensitive to oxidative stress due to the defects in cell cycle arrest. Oxidative stress inhibits E2F1 transcriptional activity, independent of changes in association with Rb and without decreasing its DNA-binding activity. Upon oxidative insult, SUMO2 is extensively conjugated to E2F1 mainly at lysine 266 residue, which specifically modulates E2F1 transcriptional activity to enhance cell cycle arrest for cell survival. We identify SENP3, a desumoylating enzyme, as an E2F1-interacting partner. Oxidative stress inhibits the interaction between E2F1 and SENP3, which leads to accumulation of sumoylated E2F1. SENP3-deficient cells exhibit hypersumoylation of E2F1 and are resistant to oxidative insult. High levels of SENP3 in breast cancer are associated with elevated levels of E2F targets, high tumor grade, and poor survival. Given the prevalence of elevated levels of SENP3 across numerous cancer types, the SENP3-E2F1 axis may serve as an avenue for therapeutic intervention in cancer.

scholarly journals Arsenic hexoxide has differential effects on cell proliferation and genome-wide gene expression in human primary mammary epithelial and MCF7 cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Donguk Kim ◽  
Na Yeon Park ◽  
Keunsoo Kang ◽  
Stuart K. Calderwood ◽  
Dong-Hyung Cho ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cancer Cells ◽  
Mammary Epithelial ◽  
Mcf7 Cells ◽  
Differential Effects ◽  
Cycle Arrest ◽  
Genome Wide ◽  
Human Mammary Epithelial ◽  
Genome Wide Gene Expression

AbstractArsenic is reportedly a biphasic inorganic compound for its toxicity and anticancer effects in humans. Recent studies have shown that certain arsenic compounds including arsenic hexoxide (AS4O6; hereafter, AS6) induce programmed cell death and cell cycle arrest in human cancer cells and murine cancer models. However, the mechanisms by which AS6 suppresses cancer cells are incompletely understood. In this study, we report the mechanisms of AS6 through transcriptome analyses. In particular, the cytotoxicity and global gene expression regulation by AS6 were compared in human normal and cancer breast epithelial cells. Using RNA-sequencing and bioinformatics analyses, differentially expressed genes in significantly affected biological pathways in these cell types were validated by real-time quantitative polymerase chain reaction and immunoblotting assays. Our data show markedly differential effects of AS6 on cytotoxicity and gene expression in human mammary epithelial normal cells (HUMEC) and Michigan Cancer Foundation 7 (MCF7), a human mammary epithelial cancer cell line. AS6 selectively arrests cell growth and induces cell death in MCF7 cells without affecting the growth of HUMEC in a dose-dependent manner. AS6 alters the transcription of a large number of genes in MCF7 cells, but much fewer genes in HUMEC. Importantly, we found that the cell proliferation, cell cycle, and DNA repair pathways are significantly suppressed whereas cellular stress response and apoptotic pathways increase in AS6-treated MCF7 cells. Together, we provide the first evidence of differential effects of AS6 on normal and cancerous breast epithelial cells, suggesting that AS6 at moderate concentrations induces cell cycle arrest and apoptosis through modulating genome-wide gene expression, leading to compromised DNA repair and increased genome instability selectively in human breast cancer cells.

scholarly journals Iodide- and Glucose-Handling Gene Expression Regulated by Sorafenib or Cabozantinib in Papillary Thyroid Cancer

2015 ◽  
Vol 100 (5) ◽  
pp. 1771-1779 ◽  
Author(s):  
Maomei Ruan ◽  
Min Liu ◽  
Qianggang Dong ◽  
Libo Chen
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Signal Transduction ◽  
Cell Proliferation ◽  
Thyroid Cancer ◽  
Western Blot ◽  
Glucose Transporter ◽  
Signal Transduction Pathways ◽  
Papillary Thyroid ◽  
Cycle Arrest

Abstract Context: The aberrant silencing of iodide-handling genes accompanied by up-regulation of glucose metabolism presents a major challenge for radioiodine treatment of papillary thyroid cancer (PTC). Objective: This study aimed to evaluate the effect of tyrosine kinase inhibitors on iodide-handling and glucose-handling gene expression in BHP 2-7 cells harboring RET/PTC1 rearrangement. Main Outcome Measures: In this in vitro study, the effects of sorafenib or cabozantinib on cell growth, cycles, and apoptosis were investigated by cell proliferation assay, cell cycle analysis, and Annexin V-FITC apoptosis assay, respectively. The effect of both agents on signal transduction pathways was evaluated using the Western blot. Quantitative real-time PCR, Western blot, immunofluorescence, and radioisotope uptake assays were used to assess iodide-handling and glucose-handling gene expression. Results: Both compounds inhibited cell proliferation in a time-dependent and dose-dependent manner and caused cell cycle arrest in the G0/G1 phase. Sorafenib blocked RET, AKT, and ERK1/2 phosphorylation, whereas cabozantinib blocked RET and AKT phosphorylation. The restoration of iodide-handling gene expression and inhibition of glucose transporter 1 and 3 expression could be induced by either drug. The robust expression of sodium/iodide symporter induced by either agent was confirmed, and 125I uptake was correspondingly enhanced. 18F-fluorodeoxyglucose accumulation was significantly decreased after treatment by either sorafenib or cabozantinib. Conclusions: Sorafenib and cabozantinib had marked effects on cell proliferation, cell cycle arrest, and signal transduction pathways in PTC cells harboring RET/PTC1 rearrangement. Both agents could be potentially used to enhance the expression of iodide-handling genes and inhibit the expression of glucose transporter genes.

Extinction of insulin gene expression in hybrids between beta cells and fibroblasts is accompanied by loss of the putative beta-cell-specific transcription factor IEF1

1991 ◽  
Vol 11 (3) ◽  
pp. 1547-1552
Author(s):  
D Leshkowitz ◽  
M D Walker
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Binding Activity ◽  
Insulin Gene ◽  
Hybrid Cells ◽  
Dna Binding Activity ◽  
Insulin Producing Cells ◽  
Insulin Gene Expression ◽  
Insulinoma Cells

Insulin-producing cells and fibroblasts were fused to produce hybrid lines. In hybrids derived from both hamster and rat insulinoma cells, no insulin mRNA could be detected in any of seven lines examined by Northern (RNA) analysis despite the presence in each line of the insulin genes of both parental cells. Hybrid cells were transfected with recombinant chloramphenicol acetyltransferase plasmids containing defined segments of the rat insulin I gene 5' flank. We observed no transcriptional activity of the intact insulin enhancer or of IEB2, a critical cis-acting element of the insulin enhancer. IEB2 has previously been shown to interact in vitro with IEF1, a DNA-binding activity observed selectively in insulin-producing cells. Hybrid cells showed no detectable IEF1 activity. Furthermore, the insulin enhancer was unable to reduce transcription directed by the Moloney sarcoma virus enhancer in a double-enhancer construct. Thus, extinction of insulin gene expression in the hybrids apparently does not operate through a direct action of repressors on the insulin enhancer; rather, extinction is accompanied by, and may be caused by, reduced DNA-binding activity of the putative transcriptional activator IEF1.

scholarly journals Overexpression of mitogen-activated protein kinase (ERK1) enhances T- cell cytokine gene expression: role of AP1, NF-AT, and NF-KB

Blood ◽  
1993 ◽  
Vol 82 (8) ◽  
pp. 2470-2477 ◽  
Author(s):  
JH Park ◽  
L Levitt
Keyword(s):  
Gene Expression ◽  
T Cell ◽  
Dna Binding ◽  
Map Kinase ◽  
Binding Activity ◽  
Cytokine Gene Expression ◽  
Cytokine Gene ◽  
Dna Binding Activity ◽  
Mitogen Activated Protein

Abstract Transfected Jurkat cells overexpressing extracellular signal-regulated kinase (ERK1), also referred to as mitogen-activated protein (MAP) kinase, were selected by Western blotting assay using anti-ERK1 and antiphosphotyrosine antibodies in combination with a functional MAP kinase assay. We then asked whether enhanced ERK1 expression had any effect on induction of T-cell cytokine genes. The results show that overexpression of ERK1 enhances expression of T-cell interleukin-2 (IL- 2), IL-3, and granulocyte-macrophage colony-stimulating factor mRNA; no change was seen in expression of the alpha-actin gene. DNA-binding activities of the transcription factors AP1, NF-AT, and NF-kB were specifically increased twofold to fourfold in ERK1-overexpressing clones relative to nontransformed or vector-transformed cells, whereas no enhancement of CK1-CK2 protein DNA binding activity was detected after ERK1 overexpression. Additionally, increased NF-AT DNA binding activity was associated with functional enhancement of NF-AT transactivating activity in ERK1-overexpressing cells. These results provide direct evidence for the role of MAP kinase in the regulation of cytokine gene expression and indicate that such regulation is likely mediated through the enhanced DNA binding activity of specific nuclear transcription factors.

scholarly journals The Balance Between Pax5 and Id2 Activities Is the Key to AID Gene Expression

2003 ◽  
Vol 198 (9) ◽  
pp. 1427-1437 ◽  
Author(s):  
Hiroyuki Gonda ◽  
Manabu Sugai ◽  
Yukiko Nambu ◽  
Tomoya Katakai ◽  
Yasutoshi Agata ◽  
...  
Keyword(s):  
Gene Expression ◽  
B Cells ◽  
Cytidine Deaminase ◽  
Regulatory Region ◽  
Binding Activity ◽  
Class Switch ◽  
Dna Binding Activity ◽  
Activation Induced Cytidine Deaminase ◽  
Putative Regulatory Region ◽  
Kinetics Of

Pax5 activity is enhanced in activated B cells and is essential for class switch recombination (CSR). We show that inhibitor of differentiation (Id)2 suppresses CSR by repressing the gene expression of activation-induced cytidine deaminase (AID), which has been shown to be indispensable for CSR. Furthermore, a putative regulatory region of AID contains E2A- and Pax5-binding sites, and the latter site is indispensable for AID gene expression. Moreover, the DNA-binding activity of Pax5 is decreased in Id2-overexpressing B cells and enhanced in Id2−/− B cells. The kinetics of Pax5, but not E2A, occupancy to AID locus is the same as AID expression in primary B cells. Finally, enforced expression of Pax5 induces AID transcription in pro–B cell lines. Our results provide evidence that the balance between Pax5 and Id2 activities has a key role in AID gene expression.

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