Extracellular vesicle-encapsulated microRNA-424 exerts inhibitory function in ovarian cancer by targeting MYB

BACKGROUND: Recent studies have suggested a crucial role of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in ovarian cancer treatment. We, therefore, set out to explore the mechanism through which MSC-derived EVs delivered microRNA-424 (miR-424) to influence the development of ovarian cancer. METHODS: Bioinformatics analyses were first performed to screen ovarian cancer-related differentially expressed genes and to predict regulatory miRNAs. Then, dual-luciferase reporter gene assay was carried out to verify the relationship between miR-424 and MYB. Subsequently, the characterized MSCs and isolated EVs were co-cultured with ovarian cancer cells, followed by determination of the expression patterns of miR-424, MYB, vascular endothelial growth factor (VEGF), and VEGF receptor (VEGFR), respectively. In addition, the effects of EVs-delivered miR-424 on the proliferation, migration, invasion and tube formation of ovarian cancer cells were assessed using gain- and loss-of-function approaches. Lastly, tumor xenograft was induced in nude mice to illustrate the influence of EVs-loaded miR-424 on ovarian cancer in vivo. RESULTS: Our data exhibited that MYB was highly-expressed and miR-424 was poorly-expressed in ovarian cancer. More importantly, MYB was identified as a target gene of miR-424. Additionally, the transfer of miR-424 by MSC-derived EVs was found to repress the proliferation, migration, and invasion of ovarian cancer cells, with a reduction in the expressions of VEGF and VEGFR. Furthermore, MSC-derived EVs over-expressing miR-424 could inhibit the proliferation, migration, and tube formation of human umbilical vein endothelial cells, and also suppressed tumorigenesis and angiogenesis of ovarian tumors in vivo. CONCLUSION: Collectively, our findings indicate that MSC-derived EVs transfer miR-424 to down-regulate MYB, which ultimately led to the inhibition of the tumorigenesis and angiogenesis of ovarian cancer. Hence, this study offers a potential prognostic marker and a therapeutic target for ovarian cancer.