Abstract：Objective To investigate the effect of silencing of ataxia-telangiectasia mutated (ATM) expression by plasmid-mediated RNA interference on the radiosensitivity of human lung adenocarcinoma A549 cells. Methods Eukaryotic expression plasmid containing ATM small interfering RNA (siRNA)(pSilencer2.1-ATM), as well as pSilencer2.1-nonspecific, was constructed. Lung adenocarcinoma A549 cells were divided into positive group, negative group, and control group to be transfected with pSilencer2.1-ATM, pSilencer2.1-nonspecific, and no plasmid, respectively. The mRNA and protein expression of ATM was measured by RT-PCR and Western blot, respectively. The change in cell radiosensitivity was observed by colony-forming assay. Cell cycle and cell apoptosis were analyzed by flow cytometry. Results The eukaryotic expression plasmid containing ATM siRNA was successfully constructed. The RT-PCR and Western blot demonstrated that the expression of ATM was down-regulated in the positive group. The sensitization enhancement ratios (D0 ratios) for the positive group and negative group were 1.50 and 1.01, respectively. The flow cytometry revealed that the proportions of A549 cells in G1 and G2/M phases were significantly lower in the positive group than in the control group (51.27% vs 61.85%, P=0.012;6.34% vs 10.91%, P=0.008) and that the apoptosis rate was significantly higher in the positive group than in the control group and negative group (49.31% vs 13.58%, P=0.000;49.31% vs 13.17%, P=0.000). Conclusions Silencing of ATM expression may increase the radiosensitivity of human lung adenocarcinoma A549 cells, probably by affecting the cell cycle and promoting cell apoptosis.
Liu Xiaoqun,Qiao Tiankui.. Effect of silencing of ATM expression by siRNA on radiosensitivity of human lung adenocarcinoma A549 cells[J]. Chinese Journal of Radiation Oncology, 2014, 23(1): 73-77.
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