miR-532-3p suppresses proliferation and invasion of ovarian cancer cells via GPNMB/HIF-1α/HK2 axis

Objective: Identifying a new target of miR-532-3p and studying its functional mechanism to explore the detailed anti-tumor mechanism of miR-532-3p in ovarian cancer. Methods: Biological and molecular methods including real-time quantitative PCR (RT-qPCR), Western blotting, colony formation, in vitro migration and invasion assays, glucose consumption and lactate production assays, RNA interference and tumor xenograft mouse models were used to study the role of miR-532-3p and its target in ovarian cancer. mRNA sequencing, dual-luciferase reporter assay and immunohistochemistry (IHC) were used to identify miR-532-3p target. STRING dataset analysis, qPCR and Western blotting were used to investigate the downstream pathway of the target of miR-532-3p. Results: Forced expression of miR-532-3p inhibited the proliferation, migration and invasion of ovarian cancer cells in vitro and the tumor growth in nude mice. RNA sequencing found 299 mRNAs were downregulated in miR-532-3p-overexpressed ovarian cancer cells, and bioinformatic analysis indicated Glycoprotein Non -metastatic Melanoma Protein B (GPNMB), a type I membrane glycoprotein, was the potential target of miR-532-3p. GPNMB was reduced at both RNA and protein levels in miR-532-3p-overexpressed ovarian cancer cells. Dual-luciferase reporter assay determined GPNMB as the target of miR-532-3p. Interference of GPNMB inhibited the proliferation, migration, invasion, glucose consumption and lactate production of ovarian cancer cells. Knocking down of GPNMB reduced the protein level of HIF-1 alpha without affecting HIF-1 alpha mRNA level. Over -expression of GPNMB reversed the antitumor effect of miR-532-3p. Conclusion: miR-532-3p exerted the anti-cancer effect by targeting GPNMB/ HIF-1 alpha/ HK2 pathway to inhibit aerobic glycolysis in ovarian cancer.