MicroRNA-203 inhibits proliferation and invasion, and promotes apoptosis of osteosarcoma cells by targeting Runt-related transcription factor 2.

Accumulating evidence indicates that microRNA-203 (miR-203) is abnormally expressed in many human tumor tissues and significantly associated with the occurrence, development and clinical outcomes of human tumors. The aim of this study was to determine the target genes and functional significance of miR-203 in osteosarcoma cells. We found reduced expression of miR-203 in osteosarcoma tissues and cells (MG63 and U2-OS) compared with the adjacent normal tissues and normal osteoblastic cells (hFOB1.19), respectively. In vitro studies further demonstrated that exogenous miR-203 overexpression inhibited osteosarcoma cell proliferation and invasion, and promoted apoptosis. At the molecular level, our results confirmed that apoptosis, cell cycle and invasion-related proteins were regulated by miR-203. Our findings also revealed that Runt-related transcription factor 2 (RUNX2) was directly negatively regulated by miR-203. These results suggested that miR-203 may function as a tumor suppressor and may therefore have therapeutic potential in the treatment of human osteosarcoma.