沉默 ATM基因对人胃癌细胞 BGC823放射敏感性的影响

目的：探讨毛细血管扩张突变基因（ATM）对人胃癌细胞放射敏感性的影响。方法：将 ATM基因敲减后获取得到的稳定转染克隆细胞和空载细胞同时通过不同剂量的照射后，观察敲减 ATM基因前后 BGC823细胞平板克隆形成率，并使用流式细胞术，观察 ATM被敲减后对细胞周期和凋亡的影响。结果：BGC823细胞中的 ATM被敲减后，经不同剂量的照射（2、4、6和8Gy）克隆形成率分别为（15．4±0．9）％、（9．2±0．3）％、（2．2±0．1）％和（1．0±0．1）％，远低于空载细胞的克隆形成率分别为（28．1±0．6）％、（15．6±0．8）％、（5．3±0．1）％和（1．8±0．1）％，P 均小于0．05，有显著性差异。采用相同剂量（4Gy）照射后，流式细胞术检测发现，BGC823细胞中的 ATM被敲减后，细胞周期被阻滞，细胞停止生长，并在12h 后出现凋亡的现象。结论：ATM基因的表达可影响胃癌细胞的放射敏感性，ATM的表达被敲减后对 BGC823细胞的放射起到增敏作用。ATM基因在胃癌放射敏感性方面可能有非常重要的作用。

Effect of silencing of ATMexpression by siRNA on radiosensitivity of human gastric adeno-carcinoma BGC823 cells

Objective:To study the effect of interference of ataxia -telangiectasia mutated(ATM)expression of the radiosensitivity on human gastric cancer BGC823 cells.Methods:Using the plasmid of interfering RNA to trans-fect BGC823 cells.The mRNA and protein expression level of ATMwas measured by RT -PCR,Real -time PCR and Western blot,respectively.Using the colonies formation assay to observe the change of cell radiosensitivity by different doses of irradiation.Cell cycle and cell apoptosis were analyzed by flow cytometry.Results:The expression of ATMin the BGC823 cells were knocked out by small interfering RNA(siRNA),the colonies formation numbers/ratios of BGC823 -Ri -ATMcells were (15.4 ±0.9)%,(9.2 ±0.3)%,(2.2 ±0.1)% and (1.0 ±0.1)% by the differ-ent doses of irradiation (2,4,6,and 8Gy),which were lower than the BGC823 -Vector's colonies formation numbers/ratios (28.1 ±0.6)%,(15.6 ±0.8)%,(5.3 ±0.1)% and (1.8 ±0.1)% respectively(P <0.05).The flow cy-tometry detection that the BGC823 -Ri -ATMcells were induced cell cycle arrest and apoptosis by 4Gy intensity ra-dioactivity after 12h,but not incurred in the vector cells.Conclusion:ATM gene expression can affect the radiation sensitivity of gastric cancer cells,the silencing of ATMincrease the radiotherapy sensitization of BGC823 cells.ATM gene may play an important role in gastric cancer radiation sensitivity.