辐射增强启动子调控的p53基因联合照射对肿瘤细胞的作用

Combination effect of radiation and p53 gene regulated by a radiation-enhanced promoter on tumor cells

目的研究辐射增强启动子调控的野生型-p53抑癌基因系统联合照射对人肿瘤细胞系HeLa和A549细胞的特异性杀伤作用.方法 构建辐射增强启动子pE6（TATA）-p53,Westernblot检测不同射线剂量诱导下人肺腺癌A549细胞系和人宫颈癌HeLa细胞系中P53蛋白的表达水平,筛选出最适的照射剂量;AnnexinV-FITC试剂盒检测肿瘤细胞系早期凋亡率;利用克隆形成实验检测此系统对肿瘤细胞放射敏感性的影响.结果在HeLa和A549细胞中,P53蛋白表达均受放射线诱导增高,且在6 Gy时辐射诱导活性最高;实验组质粒的细胞早期凋亡率与转染对照组质粒的细胞早期凋亡率相比有明显提高（F=11.018、10.736,P＜0.05）.HeLa细胞和A549细胞的放射增敏比（SER）分别为2.56和2.36.结论辐射增强启动子调控的p53基因系统具有显著的诱导肿瘤细胞凋亡的作用,可以提高肿瘤细胞的辐射敏感性,对肿瘤的治疗提供了新思路.

Objective To study the specific killing effect in human carcinoma cells aftercombination treatment of radiation and p53 gene regulated by a radiation-enhanced promoter.Methods Aplasmid pE6 （TATA）-p53 was constructed.After irradiation,the expression of P53 was detected withWestern blot assay,apoptosis was detected by Annexin V-FITC,and cell survival was detected byclonogenic assay then the sensitivity enhancement ratio （SER） was analyzed for HeLa and A549 cells.Results The expression of P53 were increased in the irradiated cells and 6 Gy irradiation triggered thestrongest activity.After p53 transfection,radiation-induced apoptosis was obviously enhanced incomparison with the control group without gene transfection （F =11.018,10.736,P ＜ 0.05）.The SER ofp53-promoter was 2.36 for A549 cells and 2.56 for Hela cells.Conclusions The p53-plasmid promotercould induce apoptosis and enhance the radiosensitivity of tumor cells,which may provide a noveltherapeutic strategy for cancer treatment.