Epithelial-mesenchymal transition (EMT) is an important contributor to drug resistance in ovarian cancer. The aims of this study were to explore the potential role of the miR-302 cluster in modulating EMT and cisplatin resistance in ovarian cancer. We used qRT-PCR and western blotting to show that miR-302 expression was lower in chemoresistant than in chemosensitive cells, and miR-302 was upregulated in chemosensitive, but not chemoresistant ovarian cancer cells in response to cisplatin treatment. We identified ATAD2 as a target of miR-302 and showed that ectopic expression of miR-302 increased cisplatin sensitivity and inhibited EMT and the invasiveness of cisplatin-resistant cells in vitro by targeting ATAD2. Knockdown of ATAD2 restored cisplatin sensitivity and reversed EMT/metastasis in cisplatin-resistant cells, as shown by western blotting and invasion/migration assays. The effect of miR-302 overexpression on EMT and invasiveness was mediated by the modulation of β-catenin nuclear expression. Immunofluorescence analysis showed that ATAD2 overexpression reversed the miR-302-induced downregulation of nuclear β-catenin in cisplatin resistant cells. A xenograft tumor model was used to show that miR-302 increases the antitumor effect of cisplatin in vivo. Taken together, these results identify a potential regulatory axis involving miR-302 and ATAD2 with a role in chemoresistance, indicating that activation of miR-302 or inactivation of ATAD2 could serve as a novel approach to reverse cisplatin resistance in ovarian cancer.
Keywords: ATAD2; Cisplatin resistance; Ovarian cancer; miR-302.
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