放射诱导经Egr-1启动子调控的腺病毒介导CDglyTK基因的肿瘤靶向表达  

Tumor targeted expression of adenovirus mediated CDglyTK gene regulated by irradiation via Egr -1 promoter

作　　者：魏道严[1] 戴冰冰[1] 陈诗书[1] 

机构地区：[1]上海第二医科大学生化教研室,200025

出　　处：《中华医学杂志》2001年第16期999-1003,共5页National Medical Journal of China

基　　金：国家自然科学基金(No .3970 440 );国家 863高技术计划基金 (No .86 3 10 2 45 2 )资助项目

摘　　要：目的　构建由Egr 1基因启动子驱动CDglyTK基因表达的腺病毒载体 ,通过放射诱导调控CDglyTK基因的肿瘤靶向表达 ,用于肝癌的基因 放射治疗。方法　利用细菌内高效同源重组法 ,制备腺病毒载体AdEgr CD/TK。MM45T .Li肝癌细胞感染AdEgr CD/TK后 ,体外观察γ射线照射诱导CDglyTK基因表达及在前药 5 FC、GCV存在的条件下细胞相对存活率的变化。利用荷瘤小鼠肝癌模型观察不同处理的抑瘤效应。结果　体外实验结果显示 ,γ射线照射可明显诱导CDglyTK基因在MM45T .Li肿瘤细胞内的表达 ,并呈剂量依赖性 ;显著增强细胞对前药 5 FC、GCV的敏感性 (P <0 0 1) ;当 5 FC和GCV同时存在时具有明显的协同效应。体内抗肿瘤实验结果提示 ,与单纯肿瘤局部照射 (TLI)、瘤内注射AdEgr CD/TK +腹腔注射 5 FC +GCV等处理组相比 ,瘤内注射AdEgr CD/TK +腹腔注射 5 FC +GCV合并TLI组的抗瘤效果最好 (P <0 .0 1) ,并可使 30 %的肿瘤完全消退 ,且未见全身毒性反应的增加。结论　利用放射调控CDglyTK基因的肿瘤靶向表达 ,是一种安全。Objective To construct adenoviral vecter of AdEgr CD/TK in which CDglyTK gene was driven by Egr 1 promoter, and control the tumor targeted expression of CDglyTK gene by γ irradiation so as to observe the effects of gene radiotherapy of liver cancer. Methods Adenoviral vector of AdEgr CD/TK was generated through homologous recombination in bacteria. The expression of CDglyTK gene in MM45T.Li cells infected with AdEgr CD/TK and exposed to different doses ofγ irradiation were analyzed, and the relative survival rate of the cells in presence of prodrugs 5 FC and GCV was tested. In addition, the tumor suppression effects of different treatments were investigated in 64 mice bearing liver cancer by observing the size of tumor at interval of four days. Results In vitro experiment showed that γ irradiation markedly and dose dependently induced CDglyTK expression in MM45T.Li tumor cells, and significantly enhanced the sensitivity of MM45T.Li cells infected with AdEgr CD/TK to prodrugs 5 FC or GCV resulting in cell being killed( P <0.01). A synergetic cytotoxic effect was found when both 5 FC and GCV were added. In vivo experiment revealed that, compared with other control treatments, intratumoral injection of AdEgr CD/TK combined with intraperitoneal injection of GCV+5 FC and TLI obviously suppressed tumor growth ( P <0.01), with 30% of the tumor eradicated completely while without causing the increase of whole body cytotoxic effect. Conclusion Tumor targeted expression of CDglyTK gene under the control of irradiation represents a novel strategy for safe and effective gene therapy of cancer and might have wide application in the future.

关 键 词：腺病毒 基因疗法 基因表达调控 肿瘤 放射疗法 

分 类 号：R73-36[医药卫生—肿瘤]