EZH2 Mediated Metabolic Rewiring Promotes High-grade Serous Ovarian Cancer Progression Independently of Histone Methyltransferase Activity

Despite EZH2 is overexpressed and exerts an oncogenic role in various cancer through catalytic-dependent or -independent manner, the mechanisms of EZH2 contributing to high-grade serous ovarian cancer (HGSOC) are incompletely understood. Here, we showed that a subgroup of HGSOC patients with high EZH2 expression but low H3K27me3 level exhibited worst prognosis. We demonstrated that EZH2 degradation but not catalytic inhibition profoundly lowered EZH2 protein and blocked cell proliferation and tumorigenicity in vitro and in vivo. Ectopic expression of EZH2 without SET domain (EZH2-∆SET), which is known to be essential for catalytic activity, restored the phenotypes of EZH2 degradation. Mechanistically, we identified that IDH2 was transactivated by EZH2 to impair metabolic rewiring by disrupting the TCA cycle, which contributed to the oncogenic role of EZH2 in OC. Together, these data reveal a novel carcinogenic role of EZH2 in HGSOC, and provide potential strategies in HGSOC by targeting EZH2 non-catalytic activity. RNA-seq for OVCAR8 treated with DZNep or doxycycline-induced EZH2 silence was performed (duplicate).