miR-31 inhibits proliferation and promotes apoptosis of osteosarcoma cells through PAX9

Objective: To investigate the role of microRNA-31 (miR-31) in osteosarcoma and the molecular mechanism of miR-31 in proliferation and apoptosis of osteosarcoma. Methods:real-time quantitative PCR (qRT-PCR) was used to detect the expression of miR-31 in human osteosarcoma. Pearson 's chisquared was applied to detect the correlation between miR-31 and clinicopathological features. CCK-8 and ANNEXIN-FITC/PI double staining were used to detect the proliferation and apoptosis of osteosarcoma cells. Results: The results of qRT-PCR showed that the expression of miR-31 was down-regulated in osteosarcoma tissues compared with matched precancerous bone tissues. The level of miR-31 in osteosarcoma tissues with high-grade malignancy and poor overall survival was even lower. CCK-8 and Annexin-FITC/PI double staining assays showed that miR-31 inhibited proliferation and promoted apoptosis of osteosarcoma cells. According to luciferase assay, miR-31 inhibited PAX9 expression directly. And PAX9 promoted proliferation and inhibited apoptosis of osteosarcoma cells. Conclusion:miR-31 inhibits proliferation and promotes apoptosis of osteosarcoma cells by targeting PAX9. miR-31 and PAX9 can be used as therapeutic targets for osteosarcoma.