MicroRNA-128 promotes proliferation in osteosarcoma cells by downregulating PTEN.

MicroRNAs are a class of small noncoding RNAs that function as critical gene regulators through targeting mRNAs for translational repression or degradation. Several studies have indicated that abnormal expression of miRNAs occurs frequently in human osteosarcoma. In the present study, we found that miR-128 expression was significantly increased in osteosarcoma tissues compared to adjacent normal tissues. Ectopic overexpression of miR-128 significantly promoted while suppression of miR-128 by its antisense inhibited the proliferation of MG63 and U2OS cells. At the molecular level, our results demonstrated that miR-128 overexpression could repress expression of PTEN by directly targeting PTEN 3'-untranslated region. Consistently, downstream AKT signaling was altered by miR-128 overexpression or knockdown. Therefore, our results suggest that miR-128 plays an important role in the proliferation of human osteosarcoma cells by directly regulation of PTEN/AKT signaling.