microRNA-363 plays a tumor suppressive role in osteosarcoma by directly targeting MAP2K4.

Abnormal expression of microRNAs plays important functions in osteosarcoma. The aim of this study was to investigate expression, functions and molecular mechanisms of microRNA-363 in osteosarcoma. Quantitative Real-time PCR was used to detect the expression level of microRNA-363 in osteosarcoma tissue samples and cell lines. After transfection, CCK8 assay, cell migration and invasion assay, western blot and Dual-Luciferase report assay were performed in human osteosarcoma cells. According to the results, we found that microRNA-363 was down-regulated in osteosarcoma tissues and cell lines. In addition, low expression level of microRNA-363 was associated with tumor size, clinical stage and distant metastasis. Moreover, microRNA-363 targeted MAP2K4 to inhibit osteosarcoma cell growth, migration and invasion. In conclusion, microRNA-363 played a tumor suppressive role in osteosarcoma by directly targeting MAP2K4. These findings indicated that microRNA-363 may have therapeutic value in treating osteosarcoma.