Targeting CARM1 in ovarian cancer with EZH2 and PARP inhibitors

Coactivator-associated arginine methyltransferase 1 (CARM1)-expressing high-grade serous ovarian cancers are characterized by poor prognosis and limited therapeutic options. Here we discuss a novel therapeutic strategy to target CARM1-expressing ovarian cancer based on a combination of poly (ADP-ribose) polymerase (PARP) and enhancer of zeste homology 2 (EZH2) inhibitors

Repurposing Pan-HDAC Inhibitors for ARID1A-Mutated Ovarian Cancer

Summary: ARID1A, a subunit of the SWI/SNF complex, is among the most frequently mutated genes across cancer types. ARID1A is mutated in more than 50% of ovarian clear cell carcinomas (OCCCs), diseases that have no effective therapy. Here, we show that ARID1A mutation confers sensitivity to pan-HDAC inhibitors such as SAHA in ovarian cancers. This correlated with enhanced growth suppression induced by the inhibition of HDAC2 activity in ARID1A-mutated cells. HDAC2 interacts with EZH2 in an ARID1A status-dependent manner. HDAC2 functions as a co-repressor of EZH2 to suppress the expression of EZH2/ARID1A target tumor suppressor genes such as PIK3IP1 to inhibit proliferation and promote apoptosis. SAHA reduced the growth and ascites of the ARID1A-inactivated OCCCs in both orthotopic and genetic mouse models. This correlated with a significant improvement of survival of mice bearing ARID1A-mutated OCCCs. These findings provided preclinical rationales for repurposing FDA-approved pan-HDAC inhibitors for treating ARID1A-mutated cancers. : Fukumoto et al. show that ARID1A mutation confers sensitivity to pan-HDAC inhibitors such as SAHA in ovarian cancers. This correlated with enhanced growth suppression induced by the inhibition of HDAC2 activity in ARID1A-mutated cells. These findings provided preclinical rationales for repurposing FDA-approved pan-HDAC inhibitors for treating ARID1A-mutated cancers. Keywords: ovarian cancer, ARID1A, HDAC2, pan-HDAC inhibitor, SAHA, SWI/SNF, chromatin remodelin