Exosomal miR-34b inhibits proliferation and the epithelial-mesenchymal transition by targeting Notch2 in ovarian cancer

Exosomal microRNA (miR) can affect signaling pathways in various physiological and pathological conditions, including ovarian cancer (OC). miR-34b, the first microRNA targeted in a human clinical trial for cancer treatment, exhibited decreased expression in several cancer types. However, the biological function of exosomal miR-34b in OC has not been elucidated. In the present study, using reverse transcription-quantitative PCR, it was reported that exosomal miR-34b is downregulated in OC cells. Exosomal miR-34b reduced cell proliferation and epithelial-mesenchymal transition (EMT) in the OC cell line SKOV3. In addition, it was confirmed that Notch2, which is upregulated in SKOV3 cells, is a target of miR-34b. Moreover, exosomal miR-34b and Notch2 levels were found to be negatively correlated. The present data highlights the importance of exosomal miR-34b-mediated inhibition of cell proliferation and EMT, suggesting that exosomal miR-34b has value as a diagnostic biomarker and a potential molecular target for the treatment of OC.