miR-139 inhibits osteosarcoma cell proliferation and invasion by targeting .

miR-139 has a tumor suppressor effect in many tumors. Here, we examined the suppressive role of this miRNA and its target, in osteosarcoma (OS), a highly malignant bone tumor that mainly affects children and adolescents. The expression of miR-139 was down-regulated in OS. Overexpression of miR-139 significantly inhibited OS cell proliferation, migration, and invasion. Ectopic expression of miR-139 down-regulated , a target of miR-139, by direct binding to its 3' untranslated region (3'UTR). Direct  siRNA-mediated silencing of exerted an inhibitory effect on OS cell proliferation and invasion similar to the effect of miR-139. transfection reversed the suppressive effect of miR-139 on OS cell proliferation and invasion. Both miR-139 and siRNA knockdown of significantly down-regulated and and up-regulated and . The data provided here show that miR-139 exerts suppressive effects on proliferation and invasion of OS cells by targeting .