【摘要】 利用EGR 1启动子、CDglyTK构建pcDNA3 EGR CDglyTK重组载体 ,以pcDNA3 CMV CDglyTK质粒为对照 ,经阳离子脂质体LipofectAMINE介导转染人肝癌 740 2细胞株 ,给予不同剂量 γ射线照射 ,通过Northern印迹、Western印迹分析 ,结果表明电离辐射可诱导转染pcDNA3 EGR CDglyTK肿瘤细胞中CDglyTK的表达 ,并呈剂量依赖性 ;而在pcDNA3 CMV CDglyTK实验组中无此诱导特性。转染pcDNA3 EGR CDglyTK的肿瘤细胞单独给予 8Gy的 γ 射线处理未见细胞明显死亡 ,而电离辐射与前药 [5 FC(fluorocytosine) +GCV]的联合大大增强了杀伤肿瘤细胞的作用。研究结果证实EGR 1启动子具有电离辐射诱导特性 ,同时提示CMV启动子无此特性 ;5 FC与GCV的配伍有协同效应 ,电离辐射可明显增强肿瘤细胞对 5 FC、GCV的敏感性 ,其细胞毒性大于单独自杀基因或单独放疗。更多还原

【Abstract】 EGR-1 gene promoter and CDglyTK gene were used to construct the pcDNA3-EGR-CDglyTK recombinant vector, in which CDglyTK gene expression was under the control of EGR-1 gene promoter. Cationic liposome LipofectAMINE was used to transfect plasmids into human hepatoma 7402 cell line. Subsequently, the transfected cells were treated with different doses of γ-ray. Northern blot and Western blot showed that ionizing radiation can induce CDglyTK gene expression drived by EGR-1 promoter,in a dose-dependant manner. There was no ionizing radiation-inducible effect in pcDNA3-CMV-CDglyTK control group. Ionizing radiation also markedly enhanced the sensitivity of tumor cells transfected with pcDNA3-EGR-CDglyTK to prodrugs (GCV/5-FC) in tumor cell killing. The data indicated that EGR-1 promoter was inducible by ionizing radiation, whereas the CMV promoter was not. There was a synergetic effect between GCV and 5-FC. The cytotoxic effect of the suicide gene-ionizing radiation combination was stronger than suicide gene alone or ionizing radiation alone.更多还原