MicroRNA-103 Promotes Proliferation and Inhibits Apoptosis in Spinal Osteosarcoma Cells by Targeting p57

Osteosarcoma is one of the most aggressive malignancies with poor prognosis rates. Many studies have demonstrated that miRNAs were involved in osteosarcoma, but the role of miR-103a in osteosarcoma remains elusive. In this study, we detected the expression levels of miR-103 in osteosarcoma and non-osteosarcoma tissues and cell lines. The binding effect of miR-103 on p57 was detected by luciferase reporter assay. After altering expressions of miR-103 or p57, viability, migration, invasion, and apoptosis of MG63 cells and expressions of proteins related with the JNK/STAT and mTOR pathways were all detected. We found the higher expression of miR-103 in osteosarcoma tissues and cell lines compared with non-osteosarcoma tissues and cell lines. miR-103 overexpression promoted survival, migration, and invasion of MG63 cells. Knockdown of miR-103a inhibited cell survival, migration, and invasion by upregulating the expression of p57, which was a target of miR-103. Moreover, miR-103a overexpression activated the JNK/STAT and mTOR pathways probably through inhibiting p57 expression. In conclusion, miR-103a acted as an oncogene in osteosarcoma, probably through activating the JNK/STAT and mTOR pathways by inhibiting p57 expression.