Effect of down-regulation of miR-3917 on proliferation and expression of PER2 in lung cancer A549 cells

LI Peng; WEN Shilei; ZHANG Feng

doi:10.3969/j.issn.1009-0460.2018.01.003

Abstract：Objective To investigate the effect of microRNA-3917 (miR-3917) on the proliferation of lung cancer cells and the expression of biological clock gene Period2 (PER2). Methods The recovered A549 cells were cultured to logarithmic growth phase. The pEGFP-miR-3917-siRNA plasmid vector targeting miR-3917 was transfected into A549 cells by 10, 20 and 50 nmol/L liposome. The expression of green fluorescent protein was observed under fluorescence microscope after 48 h transfection. According to the experimental design, they were divided into control group, empty load group and interference group. The plasmid concentration in empty load group and interference group was 50 nmol/L. The real-time quantitative PCR (QPCR) was used to detect the relative expression of miR-3917 at 48 h after transfection. The mRNA and protein levels of PER2 were detected by QPCR and Western blotting after at 48 h after transfection, respectively. The inhibitive rates of proliferation at 24, 48 and 72 h after transfection were detected by CCK-8 assay. Dual luciferase target assay was employed to verify that PER2 was a direct target of miR-3917. Results The relative expression levels of miR-3917 in control group, empty load group and interference group were 1.007±0.018,1.068±0.084 and 0.171±0.052. The relative expression level of miR-3917 in the interference group was lower than that in the control group and empty load group, and the difference was statistically significant (P<0.05). The relative expression levels of PER2 were 1.060±0.129, 1.086±0.229 and2.920±0.927 in the control group, empty load group and interference group, and the protein levels were 0.204±0.046, 0.183±0.043 and 0.512±0.117. The mRNA and protein levels of PER2 in the interference group were higher than those in the control group and empty load group, and the difference was statistically significant (P<0.05). Compared with the control group and empty load group, the proliferative ability decreased in interference group. The inhibitive rates of proliferation were (34.192±5.268)％, (33.527±6.603)％ and (30.591±7. 788)％ at 24,48,72 h in interference group, higher than other two groups, and the difference was statistically significant (P<0.05). miR-3917 could significantly inhibit the luciferase activity of wild-type PER2-3' UTR plasmid transfected cells, but had no significant effect on the luciferase activity of mutant PER2-3 ' UTR plasmid transfected cells. Conclusion Downregulation of miR-3917 can inhibit the proliferation of lung cancer cells and increase the expression of PER2. miR-3917 has a targeted regulation effect on PER2, and can be used as a new target for the prevention and treatment of lung cancer.