MAPRE3 as an epigenetic target of EZH2 restricts ovarian cancer proliferation in vitro and in vivo.

Ovarian cancer (OC) is a lethal gynecologic cancer and the common cause of death within women worldwide. The polycomb group protein enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase highly expressed in various tumors, including OC. However, the mechanistic basis of EZH2 oncogenic activity in OC remain incompletely understood. Bioinformatics analysis showed that the expression of MAPRE3 was lower in OC tissues than in normal tissues, and was positively correlated with the overall survival. MAPRE3 overexpression decreased cell growth, inducing cell cycle arrest and apoptosis in OC cells, whereas MAPRE3 silencing promoted proliferation and accelerated cell cycle progression of OC cells. The in vivo study validated that overexpression of MAPRE3 impeded tumor formation and growth of OC xenografts in nude mice. In addition, knockdown of EZH2 in OC cells downregulated H3K27me3 expression and increased MAPRE3 expression. Inhibiting EZH2 in OC cells reduced the enrichment of H3K27me3 on the promoter of MAPRE3. Furthermore, MAPRE3 silencing significantly reversed changes in the expression of cell cycle and apoptosis-related markers and cell growth mediated by EZH2 knockdown in OC cells. MAPRE3 functions as a suppressor of OC and is epigenetic repressed by EZH2, suggesting a potential therapeutic strategy for OC by targeting EZH2/MAPRE3 axis.