Genome analysis identifies the p15ink4b tumor suppressor as a direct target of the ZNF217/CoREST complex.
The ZNF217 oncoprotein is a constituent of a core transcriptional complex that includes CoREST, histone deacetylase 1/2, lysine demethylase 1, and the C-terminal binding protein 1/2. We have combined genome-wide expression profiling and chromatin immunoprecipitation with directed selection and ligation (ChIP-DSL) to identify a subset of genes directly regulated by ZNF217. Our results establish p15(ink4b) as a direct target of the ZNF217 complex. Downregulation of ZNF217 in MCF-7 breast cancer cells resulted in a dramatic increase in p15(ink4b) expression and coincided with increases in dimethylation of H3-K4 and, surprisingly, a decrease in K9/K14-H3 acetylation. Stimulation of HaCaT cells with transforming growth factor beta (TGF-beta) resulted in a release of ZNF217 and a concomitant binding of SMAD2 to the proximal promoter, which preceded increases in ink4b protein expression. Furthermore, the changes in chromatin marks at the p15(ink4b) promoter following TGF-beta stimulation were similar to those observed following ZNF217 downregulation. Collectively, these results establish the ZNF217 complex as a novel negative regulator of the p15(ink4b) gene and may constitute an important link between amplification of ZNF217 and the loss of TGF-beta responsiveness in breast cancer.
Thillainadesan
Gobi
G
Department of Oncology, London Regional Cancer Program and The Lawson Health Research Institute, London, Ontario, Canada.
Isovic
Majdina
M
Loney
Esther
E
Andrews
Joseph
J
Tini
Marc
M
Torchia
Joseph
J
D001943:Breast Neoplasms / Q000378:metabolism; D045744:Cell Line, Tumor; D056970:Co-Repressor Proteins; D050762:Cyclin-Dependent Kinase Inhibitor p15 / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D023281:Genomics; D006801:Humans; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000378:metabolism; D015534:Trans-Activators / Q000302:isolation & purification / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism
D056970:Co-Repressor Proteins; D050762:Cyclin-Dependent Kinase Inhibitor p15; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; C121019:RCOR1 protein, human; D012097:Repressor Proteins; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; C113698:ZNF217 protein, human