Background: Osteosarcoma (OS) is one of the most common malignant tumors of bone, and microRNAs (miRNAs/miRs) serve critical roles in the progression of human OS. The aim of the present study was to investigate the role of miR-495-3p in OS. Methods: The expression of miR-495-3p in OS tissues and adjacent tissues from 30 patients was measured by reverse transcription-quantitative PCR (RT-qPCR). Human OS cell lines (U-2 OS, MG-63 and Saos-2 cells) and normal osteoplastic cells (hFoB 1.19 cells) were employed to perform the further analysis. The cell proliferation ability of MG-63 cells was measured by Cell Counting Kit-8 assay and colony formation assay. In addition, cell invasion and migration were evaluated by Transwell and scratch wound healing assays, respectively. Flow cytometry was applied to assess cell apoptosis and the cell cycle. Moreover, RT-qPCR and Western blotting were performed to measure mRNA and protein expression. A luciferase reporter assay was used to verify the target gene of miR-495-3p. Furthermore, a xenograft OS model was made to evaluate the effect of miR-495-3p in vivo. Results: The results revealed that miR-495-3p was downregulated in the OS tissues and GBM cell lines. Additionally, miR-495-3p overexpression suppressed the proliferation, migration and invasion of MG-63 cells. Simultaneously, cell apoptosis was promoted, accompanied by cell cycle arrest, after transfecting with miR-495-3p mimics. In addition, the expression levels of cell apoptosis-related proteins were increased, whereas proteins of the cell cycle were decreased. Importantly, C1q/TNF-related protein 3 (CTRP3) was confirmed as a direct target of miR-495-3p. A xenograft tumor model was employed to verify the effects of miR-495-3p on OS. Conclusion: On the basis of these results, we conclude that miR-495-3p overexpression inhibited cell proliferation, migration and invasion by downregulating CTRP3. Therefore, miR-495-3p may act as a tumor suppressor and an underlying target for OS treatment.
Keywords: C1q/TNF-related protein 3; invasion; miR-495-3p; osteosarcoma.