Blockade of miR-663b inhibits cell proliferation and induces apoptosis in osteosarcoma via regulating TP73 expression

OBJECTIVE: This study aimed to investigate the exact role of miR-663b in osteosarcoma (OS) progression and further explore the underlying molecular mechanisms. MATERIALS AND METHODS: The miR-663b expression in human OS cell lines was determined by qRT-PCR, and the results suggested that miR-663b was highly expressed in human OS cells. TargetScan was used to predict the potential targets of miR-663b, and the prediction was confirmed by dual-luciferase reporter assay. To investigate the role of miR-663b in OS, miR-663b was down-regulated in U2OS cells using miR-663b inhibitor. CCK8 and flow cytometry were preformed to investigate the proliferation and apoptosis of U2OS cells. Moreover, qRT-PCR and western blot analysis were performed to measure the mRNA and protein expression. RESULTS: We found that miR-663b directly targets TP73 and negatively regulates TP73 expression. MiR-663b inhibitor significantly decreased the proliferation ability of U2OS cells, while the percentage of apoptotic cells was markedly increased. The level of Bcl-2 was notably inhibited by miR-663b inhibitor, while Bax expression was significantly enhanced. Moreover, miR-663b down-regulation promoted p53 and p21 expression in U2OS cells. CONCLUSIONS: MiR-663b down-regulation represses proliferation and induces apoptosis in OS by targeting TP73. Therefore, we provide a potential therapeutic target for OS treatment (Fig. 6, Ref. 27).