Inhibition of EZH2 Action has Contrasting Effects on Ovarian Cancer Stem Cell Populations (SRI 2022)
We demonstrated in vitro and in vivo that cisplatin and PARP inhibitors (PARPi) enrich for ovarian cancer stem cells (CSCs). Therefore, our objective was to assess how disruption of EZH2 action and/or reduction of EZH2 affects CSC populations alone or in combination with PARPi or carboplatin treatment. We treated OvCa cell lines (A2780, OVCAR4, displaying relatively high levels of EZH2) with vehicle(s), single agent EZH2 inhibitor GSK-126, carboplatin, the PARPi (olaparib), and combinations of GSK-126 with carboplatin or olaparib... Together, these data suggest EZH2 disruption of H3K27 trimethylation status negatively impacts the levels of ALDH active cells, but promotes an increase in PROM1 and subsequently CD133 positive cells. However, the combination of GSK-126 with carboplatin or PARPi was sufficient to negate the increase in CD133 positive populations suggesting the combination strategy could reduce CSC populations that contribute to recurrence.