Abstract
Cancer cells acquire essential characteristics for metastatic dissemination through the process of epithelial-to-mesenchymal transition (EMT), which is regulated by gene expression and chromatin remodeling changes. The enhancer of zeste homolog 2 (EZH2), the catalytic subunit of the polycomb repressive complex 2 (PRC2), catalyzes trimethylation of lysine 27 of histone H3 (H3K27me3) to repress gene transcription. Here we report the functional roles of EZH2-catalyzed H3K27me3 during EMT in ovarian cancer (OC) cells. TGF-β-induced EMT in SKOV3 OC cells was associated with decreased levels of EZH2 and H3K27me3 (P < 0.05). These effects were delayed (~72 h relative to EMT initiation) and coincided with increased (> 15- fold) expression of EMT-associated transcription factors ZEB2 and SNAI2. EZH2 knockdown (using siRNA) or enzymatic inhibition (by GSK126) induced EMT-like changes in OC cells. The EMT regulator ZEB2 was upregulated in cells treated with either approach. Furthermore, TGF-β enhanced expression of ZEB2 in EZH2 siRNA- or GSK126-treated cells (P < 0.01), suggesting that H3K27me3 plays a role in TGF-β- stimulated ZEB2 induction. Chromatin immunoprecipitation assays confirmed that TGF-β treatment decreased binding of EZH2 and H3K27me3 to the ZEB2 promoter (P < 0.05). In all, these results demonstrate that EZH2, by repressing ZEB2, is required for the maintenance of an epithelial phenotype in OC cells.
Original language | English (US) |
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Pages (from-to) | 84453-84467 |
Number of pages | 15 |
Journal | Oncotarget |
Volume | 7 |
Issue number | 51 |
DOIs | |
State | Published - 2016 |
Funding
This work was supported by the National Cancer Institute (CA182832 to DM and KN) and the V Foundation (to DM and KN).
Keywords
- EMT
- EZH2
- GSK126
- H3K27me3
- Ovarian cancer
ASJC Scopus subject areas
- Oncology