MiR-362 suppresses cervical cancer progression via directly targeting BAP31 and activating TGFβ/Smad pathway

BAP31 (B-cell receptor-associated protein 31) is an important regulator of intracellular signal transduction and highly expressed in several cancer tissues or testicular tissues. Our previous study had revealed that elevated BAP31 plays a crucial role in the progress and metastasis of cervical cancer. Even so, the precise mechanism of abnormal BAP31 elevation in cervical cancer has not been fully elucidated. We revealed that the expression of BAP31 was mainly regulated by microRNA-362 (miR-362), which was markedly downregulated in cervical cancer tissues and negatively correlated with clinical tumor staging. Overexpression of miR-362 inhibited cervical cancer cell proliferation and increased the proportion of apoptotic cells. Furthermore, miR-362 reduced the tumor sizes and prolonged mice survival time in xenograft nude mice model. Finally, we demonstrated that the BAP31/SPTBN1 complex regulated tumor progression through the Smad 2/3 pathway under the control of miR-362. Collectively, our findings demonstrated that miR-362 could work as an anti-oncomiR that inhibits proliferation and promotes apoptosis in cervical cancer cells via BAP31 and TGFβ/Smad pathway. Overexpression of miR-362 might be a potential therapeutic strategy for cervical cancer.