Regulatory Effect Of MiRNA34a On DNMT1 Gene Expression In Osteosarcoma

OBJECTIVE: To investigate the effect of up-regulating the expression of mi RNA34 a in osteosarcoma cell line MG-63 to explore its effect on the downstream target gene-DNA methyltransferase 1 gene(DNMT1)and its apoptosis and proliferation of osteosarcoma cells,Learning gene targeting therapy to open up new ideas and lay the foundation for the experiment.METHODS: The experiment was divided into three groups: A group: blank group(untreated group);B group: negative control group(transfection invalid plasmid);C group: experimental group(transfection group).Lentivirus was used to construct a transfected plasmid stably expressing mi RNA34a:pc DNA3.1/pri-mi RNA34 a.The osteosarcoma cell line of the experimental group was successfully transfected,and a well-growing and stable cell line was constructed.Similarly,the negative control group was treated with a lentivirus-negative plasmid(pc DNA3.1).The blank group cell lines were not treated.Real-time fluorescence quantitative PCR was used to detect the changes of DNMT1 m RNA in the three groups of cells before and after transfection.Western Blot assay was used to detect the changes of protein expression levels in the three groups before and after transfection.Flow cytometry was used to detect changes in cell cycle,cell proliferation,and cell apoptosis and analyze them.RESULTS: After the transfection was satisfactory,the experimental data of the three cell lines were compared and analyzed.The relative expression level of DNMT1 m RNA in the experimental group(0.26±0.04)was significantly lower than that in the negative control group(1.02±0.15)and the blank control group(1.05±0.06),and the difference was statistically significant(P<0.05);The expression of DNMT1 protein was significantly lower than that of the control group(P<0.05).The proliferation of osteosarcoma cells was inhibited.The proliferation inhibition rate of the experimental group was 28.2 ± 1.69% on the 5th day after transfection;the cells of the experimental group were in the G0/G1 phase.The cell ratio was as high as 71.58±0.96%,which was significantly higher than that of the blank control group(62.99±0.67%)and the negative control group(63.54±1.33%)(P<0.05);the apoptosis was significantly increased,and the apoptosis rate of the experimental group cells was 28.20% was significantly higher than that in the blank control group(5.06%)and the negative control group(5.34%)(P<0.05).CONCLUSIONS: After transfection of pc DNA3.1/pri-mi RNA34 a plasmid with osteosarcoma MG-63 cell line,the expression of mi RNA34 a was enhanced,the m RNA and protein expression of downstream DNMT1 gene was decreased,and the apoptosis of osteosarcoma cells was promoted.Proliferation produces an inhibitory effect.mi RNA34 a has opened up new ideas for gene-targeted diagnosis and treatment of osteosarcoma in the field of molecular biology.