中文摘要：

目的 观察G蛋白信号通路调节蛋白5（RGS5）对人肺癌细胞的作用并探索其可能的分子机制.方法 采用MTT法检测过表达RGS5对人肺癌细胞系A549及Calu-3生长的影响;采用克隆形成法检测过表达RGS5及联合X射线照射对人肺癌细胞系A549及Calu-3的存活的影响;采用Western blot法检测凋亡相关蛋白的表达.结果 过表达RGS5可显著地降低人肺癌细胞系A549及Calu-3的生长,pTriEX-RGS5组在受照后48和72 h时A549、Calu-3细胞的生长抑制率分别为44.4％（F=29.18,P＜0.05）和39.27％ （F =23.04,P＜0.05）、54.3％（F=103.45,P＜0.05）和44.7％（F=108.02,P＜0.05）.RGS5可诱导肺癌细胞的凋亡,对照组、pTRiEX组及pTRiEX-RGS5组处理36 h后,A549、Calu-3细胞的凋亡率分别为（1.3±0.2）％、（3.4±0.6）％、（19.6±2.3）％（F=86.62,P＜0.05）和（3.2±0.8）％、（3.0±0.9）％、（12.8±1.8）％ （F=28.80,P＜0.05）.此外,过表达RGS5与X射线照射联合,可以显著地增强抑制肺癌细胞的存活能力.结论 RGS5可显著地抑制人肺癌细胞的生长,并且过表达RGS5可增强X射线照射对肺癌细胞的杀伤作用.

英文摘要：

Objective To investigate the effects of regulator and the underlying molecular mechanisms of G-protein signaling 5 （RGS5） on radiation response in human lung cancer cells.Methods The effects of RGS5 on viability were determined by MTT assay,and apoptosis rate was detected by flow cytometry,in human lung cancer cells.The combined effect of ionizing radiation and RGS5 on tumor cells was detected by colony formation assay.The protein expression was detected by Western blot.Results RGS5 overexpression remarkably inhibited the survival of human lung cancer cells,and the growth inhibition rate of RGS5 overexpression on A549 and Calu-3 cells were 44.4% （F =29.18,P 〈 0.05） and 39.27% （F=23.04,P〈0.05） at 48 h,and 54.3%（F=103.45,P〈0.05）,44.7%（F=108.02,P 〈 0.05） at 72 h post-irradiation,respectively.RGS5 might exert its inhibitory effects on human lung cancer cells by inducing tumor cell apoptosis,while the apoptotic cells rate in A549 and Calu-3 cells in control group,pTRiEX group and pTRiEX-RGS5 group were （1.3 ± 0.2） %,（3.4 ± 0.6） %,（19.6 ± 2.3）% （F=86.62,P〈0.05）,and （3.2±0.8）%,（3.0±0.9）%,（12.8±1.8）% （F=28.80,P 〈 0.05） at 36 h post-irradiation,respectively.Furthermore,RGS5 could sensitize the lung cancer cells to radiation.Conclusions RGS5 might play an inhibitory role in human lung cancer cell proliferation,which may explain the pathoclinical observation thet high expression of RGSS is a favorable prognostic factor in NSCLC patients.In addition,RGS5 also enhance the anti-tumor effects of radiation in human lung cancer cells.