MicroRNA-503 represses epithelial-mesenchymal transition and inhibits metastasis of osteosarcoma by targeting c-myb.

Deregulated expression of miRNAs contributes to the development of osteosarcoma. Our previous study has showed that miR-503 was downregulated in osteosarcoma tissues. However, the mechanism of the miR-503 in osteosarcoma development still remains largely undefined. In our study, we found that miR-503 overexpression suppressed cell invasion and migration and inhibited epithelial-to-mesenchymal transition (EMT) of MG-63. Furthermore, we identified that c-myb, an oncogene, was a direct target of miR-503. Moreover, overexpression of c-myb could rescue miR-503-suppressed invasion and EMT. The expression of c-myb was upregulated in osteosarcoma cell lines. Therefore, we conclude that high miR-503 expression suppressed osteosarcoma cell mobility and EMT through targeting c-myb, and this may serve as a therapeutic target.