MiR-139 prompts the development of osteosarcomas mainly through targeting ROCK1.

Abnormal expression of miR-139 was found to be aberrantly expressed in various tumors. However, whether it is involved in osteosarcomas (OS) has never been explored. In the current study, we found that the level of ROCK1 was markedly increased in OS cancer tissues compared to that of noncancerous tissues. Meanwhile, the expression of miR-139 was markedly reduced in OS cancer tissues and cell lines. Enhanced miR-139 expression markedly suppressed colony-formation and cell invasion capacity of OS cancer cells. Dual luciferase reporter assay demonstrated that ROCK1 was a target gene of miR-139. Moreover, overexpression of ROCK1 also led to increased invasion capacity in OS cancer cells even when miR-139 was inhibited, suggesting the anti-invasion effects of miR-139 were mediated through ROCK1. In summary, our present findings indicate that miR-139 functions as a tumor suppressor in OS cancer cells mainly by targeting ROCK1.