MicroRNA-132 inhibits cell growth and metastasis in osteosarcoma cell lines possibly by targeting Sox4

Increasing evidence has confirmed that dysregulation of microRNAs (miRNAs) can contribute to the progression and metastasis of human tumors. Previous studies have shown that dysregulation of microRNAs (miRNAs) can contribute to the progression and metastasis of human tumors. However, the precise mechanisms of miR-132 in osteosarcoma have not been well clarified. Real-time PCR was performed to detect the expression of miR-132 in osteosarcoma cell lines. miR-132 mimic, miR-132 inhibitor and negative control were transfected into osteosarcoma cells and the effects of miR-132 on the cell growth and metastasis were investigated. Furthermore, protein level of Sox4 was measured by western blotting. Luciferase assays were performed to validate Sox4 as miR-132 target in osteosarcoma cells. We found that miR-132 was downregulated in osteosarcoma cell lines. Introduction of miR-132 significantly inhibited proliferation, arrested cell cycle and induced apoptosis in osteosarcoma cells. Besides, invasion and epithelial-mesenchymal transition (EMT) of osteosarcoma cells was suppressed by overexpressing miR-132. However, downregulation of miR-132 promoted cell growth and metastasis in osteosarcoma cells. Bioinformatics analysis predicted that Sox4 was a potential target gene of miR-132. Luciferase reporter assay demonstrated that miR-132 could directly target Sox4. Moreover, the low level of miR-132 was associated with increased expression of Sox4 in osteosarcoma cells. Sox4 inhibition suppressed cell malignant behaviors. Overexpression of Sox4 in osteosarcoma cells transfected with miR-132 mimic partially reversed the inhibitory effect of miR-132. In conclusion, miR-132 inhibited cell growth and metastasis in osteosarcoma cells by downregulation of Sox4, and knockdown of Sox4 was essential for the miR-132-inhibited cell growth and metastasis in osteosarcoma cells.