Abstract
MicroRNAs (miRNAs/miRs) are non-coding RNAs that regulate protein synthesis by targeting mRNAs for translational repression or degradation. Previous studies have reported that aberrant expression of miR‑744 may be involved in human osteosarcoma; however, the underlying mechanisms remain elusive. In the present study, the expression levels of miR‑744 and its downstream signals were determined by reverse transcription‑quantitative PCR and western blotting. Cell proliferation was assessed using the bromodeoxyuridine assay, and the target of miR‑744 was investigated using a dual‑luciferase activity assay. The present study identified a significant upregulation of miR‑744 in osteosarcoma tissues compared with adjacent non‑tumor tissues. Furthermore, it was demonstrated that ectopic overexpression of miR‑744 induced by a miR‑744 precursor significantly enhanced proliferation of the osteosarcoma cell line MG63, whereas opposite results were observed following suppression of miR‑744 with its inhibitor. Moreover, as a unique anti‑oncogene, PTEN was identified as a direct target of miR‑744. It was confirmed that miR‑744 downregulated PTEN expression in MG63 cells by targeting the PTEN 3'untranslated region, and that the downstream AKT signal was also regulated by miR‑744. Collectively, the present results suggested that miR‑744 promoted proliferation of human osteosarcoma cells by directly regulating the PTEN/AKT signaling pathway.