Effect of miRNA-1-3p on biological function of osteosarcoma cells via myocyte enhancer factor 2A / 肿瘤研究与临床

ABSTRACT

Objective:To investigate the effect of miRNA-1-3p (miR-1-3p) on expression of myocyte enhancer factor 2A (MEF2A) and the biological function of osteosarcoma cells.Methods:The tumor tissues and adjacent normal tissues of 20 patients with osteosarcoma who were clinically diagnosed in Shanxi Provincial Cancer Hospital from January 2019 to January 2020 were collected, and the expression of miR-1-3p in the samples was detected by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). The expression of miR-1-3p in osteosarcoma cell lines U2-OS, SAOS-2, MG63, SW1353 and human normal osteoblast cell line hFOB1.19 was detected by qRT-PCR, then the cell line with the lowest expression of miR-1-3p was selected for follow-up experiments. An overexpression miR-1-3p vector was constructed (miR-1-3p mimcs). The miR-1-3p overexpression group was transfected with miR-1-3p mimcs, and the control group was transfected with empty vector (miR-1-3p nc). CCK-8 method was used to detect the proliferation activity of cells; flow cytometry was used to detect the changes of cell apoptosis and cell cycle. miRwalk database was used to predict the miR-1-3p target gene, and the target gene was verified by dual-luciferase reporter gene assay; Western blot was used to detect the expression of MEF2A protein in cells of each group.Results:Compared with adjacent tissues, the expression of miR-1-3p in osteosarcoma tissues was down-regulated (0.31±0.14 vs. 0.62±0.21), and the difference was statistically significant ( t = 5.31, P<0.01). The expression of miR-1-3p in U2-OS cells was the lowest; compared with the control group, the proliferation activity of U2-OS cells was inhibited in miR-1-3p overexpression group (48 h absorbance value 0.56±0.01 vs. 0.77±0.03, t = 2.77, P<0.01; 72 h absorbance value 0.87±0.02 vs. 1.40±0.03, t = 2.93, P<0.01); G 1/S cell cycle arrest increased [G 1 phase (38.24±0.55)% vs. (32.11±0.80)%, t = 9.27, P = 0.01; S phase (61.24±0.90)% vs. (67.78±0.83)%, t = 7.52, P = 0.02]; early apoptotic rate increased [(11.20±0.12)% vs. (1.50±0.12)%, t = 2.91, P<0.05], miRwalk database predicted that the miR-1-3p target gene was MEF2A. The result of dual-luciferase reporter gene assay showed that miR-1-3p bound to MEF2A 3'UTR, and the luciferase activity of U2-OS cells in miR-1-3p overexpression group was lower than that in the control group (renilla luciferase/firefly luciferase activity ratio 0.53±0.06 vs. 1.00±0.04, t = 4.04, P < 0.05). Western blot showed that the expression of MEF2A protein in U2-OS cells of miR-1-3p overexpression group was lower than that of the control group (protein relative expression 0.41±0.14 vs. 0.77±0.12, t = 3.93, P < 0.05). Conclusions:The low expression of miR-1-3p may be associated with the proliferation, apoptosis and cycle changes of osteosarcoma cells. miR-1-3p can negatively regulate the expression of MEF2A protein and regulate the occurrence and development of osteosarcoma.