Circular RNA circMBOAT2 promotes prostate cancer progression via a miR-1271-5p/mTOR axis

Abstract

Patients with advanced prostate cancer (PCa) have poor prognosis. Circular RNAs (circRNAs) regulate biological processes in a variety of cancers, but the precise roles of circRNAs in PCa are poorly understood. Herein, we identified a novel circRNA, termed circMBOAT2 (has_circ_0007334), which was significantly overexpressed in PCa tissues and cell lines. Overexpression of circMBOAT2 was associated with high Gleason score, advanced pathological T stage, and poor prognosis. Overexpression of circMBOAT2 promoted proliferation, migration, and invasion of PCa cells <i>in vitro</i>, and enhanced tumorigenesis and metastasis <i>in vivo</i>. Mechanistically, circMBOAT2 overexpression upregulated the expression of mTOR by acting as a decoy for miR-1271-5p, resulting in the activation of the PI3K/Akt pathway, ultimately promoting the progression of PCa. Importantly, application of an inhibitor of mTOR significantly antagonized circMBOAT2-mediated PCa tumorigenesis <i>in vivo</i>. circMBOAT2 promotes proliferation and metastasis of PCa through miR-1271-5p/mTOR axis-mediated activation of the PI3K/Akt pathway. In summary, our findings uncover a molecular mechanism in the progression of PCa and indicate that circMBOAT2 may be a useful prognostic biomarker and therapeutic target in PCa.