MicroRNA-145 targets vascular endothelial growth factor and inhibits invasion and metastasis of osteosarcoma cells.

MicroRNAs are important gene regulators that play a profound role in tumorigenesis. MicroRNA-145 (miR-145), an important member in the family of microRNAs, is under-expressed in several types of tumors and acts as a tumor suppressor. The role and probable pathways of miR-145 in osteosarcoma carcinogenesis are still unknown. In this study, we found that miR-145 was significantly under-expressed in osteosarcoma tissues, and the over-expression of miR-145 could inhibit invasion and angiopoiesis of osteosarcoma cells. Furthermore, the results showed that vascular endothelial growth factor (VEGF) expression was down-regulated in osteosarcoma cells after miR-145 transfection. On the basis of these results, we performed the luciferase assay and verified that miR-145 could down-regulate VEGF at the translational level by partially binding to VEGF 3' untranslated region (3'UTR). Therefore, it can be concluded that miR-145 can inhibit invasion and metastasis of osteosarcoma cells. One of the mechanisms is the down-regulation of VEGF expression by miR-145 by binding to the 3'UTR of VEGF mRNA specifically. These novel findings may have extensive implications for an effective gene therapy of osteosarcoma.