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G 1 / S Arrest Induced by Histone Deacetylase Inhibitor Sodium Butyrate in E 1 A Ras-transformed Cells Is Mediated through Down-regulation of E 2 F Activity and Stabilization of-Catenin *
| Content Provider | Semantic Scholar |
|---|---|
| Author | Abramova, Maria V. Pospelova, Tatiana V. Nikulenkov, Fedor Hollander, Christine M. Fornace, Albert J. Pospelov, Valery A. |
| Copyright Year | 2006 |
| Abstract | Tumor cells are often characterized by a high and growth factor-independent proliferation rate. We have previously shown that REF cells transformed with oncogenes E1A and c-Ha-Ras do not undergo G1/S arrest of the cell cycle after treatment with genotoxic factors. In this work, we used sodium butyrate, a histone deacetylase inhibitor, to show that E1A Ras transformants were able to stop proliferation and undergo G1/S arrest. Apart from inducing G1/S arrest, sodium butyrate was shown to change expression of a number of cell cycle regulatory genes. It down-regulated cyclinsD1, E, andAaswell as c-myc and cdc25A and up-regulated the cyclin-kinase inhibitor p21waf1. Accordingly, activities of cyclin E-Cdk2 and cyclin A-Cdk2 complexes in sodium butyrate-treated cells were decreased substantially. Strikingly, E2F1 expressionwas also down-modulated at the levels of gene transcription, the protein content, and the E2F transactivating capability. To further study the role of p21waf1 in the sodium butyrate-induced G1/S arrest and the E2F1 down-modulation, we established E1A Ras transformants from mouse embryo fibroblast cells with deletion of the cdkn1a (p21waf1) gene. Despite the absence of p21waf1, sodium butyrate-treated mERas transformants reveal a slightly delayed G1/S arrest as well as down-modulation of E2F1 activity, implying that the observed effects are mediated through an alternative p21waf1independent signaling pathway. Subsequent analysis showed that sodium butyrate induced accumulation of -catenin, a downstream component of the Wnt signaling. The results obtained indicate that the antiproliferative effect of histone deacetylase inhibitors on E1A Ras-transformed cells can be mediated, alongside other mechanisms, through down-regulation of E2F activity and stabilization of -catenin. Chromatin structure and eventually gene transcription are regulated at the level of histone acetylation and histone deacetylation (1–4). Higher levels of histone acetylation have been associated with transcriptional activation; correspondingly, an inactive chromatin structure correlates with histone deacetylation mediated by histone deacetylases (HDACs).3 Both of these processes, acetylation and deacetylation of histones, are involved in control of cell growth, differentiation, and apoptosis. Deregulation of these pathways can trigger development of human diseases (e.g. p300 histone acetylase gene alteration is linked with development of tumors such as colorectal and gastric carcinomas) (1, 5). Increasing evidence has been reported that HDAC inhibitors are able to suppress cell proliferation and to induceG1/S and/or G2/M block of the cell cycle in various tumor cells (2, 3, 6, 7). Moreover, it has been reported thatHDAC inhibitors can cause apoptotic cell death in a number of tumor cells (3, 8, 9). Due to theirmarked antiproliferation effect, inhibitors ofHDACactivity are currently being tested in cancer therapeutics clinical trials (2, 6). In the majority of tumor cells, there are various dysfunctions of negative regulators of the cell cycle (p21waf1 or p27kip1 cyclinCdk inhibitor and tumor suppressor p53 and/or pRb) or elevated expression of positive regulators (cyclin D, Cdks, c-Myc), allowing the cells to avoid arrest at the G1/S or G2/M checkpoints by various DNA-damaging and stress factors. The fact that HDAC inhibitors are able to stop proliferation of different transformed cells indicates that they can also utilize noncanonical p53/Waf1-independent pathways for inducing the cell cycle arrest. The mechanisms by which HDAC inhibitors stop proliferation of tumor cells are far from clear. Gene expression profiling data indicate that not more than 2% of all genes change their transcription in HDAC inhibitor-treated cells, with most of these controlling cell cycle progression (10). In this work, to study the antiproliferative effect of HDAC inhibitor sodium butyrate, we used primary embryonic fibroblast (REF andMEF) cells transformed with E1A and c-Ha-Ras * This study was supported by Russian Foundation for Basic Research Grants 06-04-49058 and 04-04-49766 and by Civilian Research and Development Foundation Grant RB1-2511-ST-03. This work also was supported in part by the “Molecular and Cell Biology,” Russian Academy of Sciences program and by an award (G-3-00-336) from NCI, National Institutes of Health (to V. A. P.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. □S The on-line version of this article (available at http://www.jbc.org) contains supplemental Fig. S1. 1 Present address: Dept. of Genetics and Complex Diseases, Harvard School of Public Health, Bldg. II, Rm. 121, 665 Huntington Ave., Boston, MA 02115. 2 To whom correspondence should be addressed. Tel.: 812-297-1816; Fax: 812-297-0341; E-mail: Pospelov_v@mail.ru. 3 The abbreviations used are: HDAC, histone deacetylase; MEF, mouse embryo fibroblast; REF, rat embryo fibroblast; RT, reverse transcription; APC, adenomatous polyposis coli; BIO, 6-bromoindirubin-3 -oxime; NaB, sodium butyrate; CREB, cAMP-response element-binding protein; GAPDH, glyceraldehyde-3-phosphate dehydrogenase. THE JOURNAL OF BIOLOGICAL CHEMISTRY VOL. 281, NO. 30, pp. 21040 –21051, July 28, 2006 Printed in the U.S.A. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.jbc.org/content/281/30/21040.full.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
