MiR-34a Inhibits Cell Proliferation and Migration in Osteosarcoma by Downregulating DNMT1

Abstract: Objective To investigate the effects of DNA methyl transferase 1 (DNMT1) gene regulation by miR-34a in osteosarcoma (OS) MG63 cells and to determine the possible mechanisms. Methods A miR-34a mimic, mimic negative control (NC), miR-34a inhibitor, or inhibitor-NC were transfected into MG63 cells using Lipofectamine 3000. Cell viability was measured using the MTT assay. The mRNA levels of DNMT1 in MG63 cells were detected by qPCR. The proliferation of MG63 cells was detected by the CCK8 method. The protein expression of DNMT1 was measured by Western blotting. The effects of DNMT1 on the migration of MG63 cells were examined by a cell migration assay. The apoptosis of MG63 cells was detected by flow cytometry. Results The mRNA levels of DNMT1 were up-regulated in MG63 cells treated with the miR-34a inhibitor compared to other groups. The growth of MG63 cells was significantly increased in these cells. The protein expression of DNMT1 and the cell proliferation and migration decreased in the miR-34a mimic-treated group compared to the cells treated with the miR-34a inhibitor or the negative control (both P < 0.05). Conclusion By targeting the DNMT1 gene, miR-34a reduces the expression level of DNMT1 in MG63 cells, thereby affecting the viability, migration, proliferation, and apoptosis of MG63 cells. Interventions targeting the miR-34a/DNMT1 axis may represent a novel targeted therapy for OS.