腺病毒介导的双自杀基因对直肠癌细胞的杀伤作用

目的 探讨直肠癌的基因治疗方法。方法 用重组腺病毒介导外源胞嘧啶脱氨酶（CD）基因、单纯疱疹病毒胸苷激酶（HSV－tk）基因转移到人直肠癌细胞系HR－8348，通过细胞集落形成实验、细胞存活率测定（MTT法），检测、分析CD和HSV－tk双自杀基因系统对肿瘤细胞的作用。结果 重组腺病毒介导的CD和HSV－tk自杀基因可在HR－8348细胞高效表达。用腺病毒穿梭质粒pAdCMV-Linkl(CD tk)、Linkl(-)、pAdCMV-Linkl(CD)、pAdCMV-Kinkl(tk）重组腺病毒感染HR－8348细胞，不加5－氟胞嘧啶（5－FC）、环氧鸟苷（GCV），各组肿瘤细胞的集落形成和存活率的差异无显著性意义（P＞0．05）。应用5－FC、GCV后，pAdCMV-Linkl(CD tk)转染组细胞集落形成和存活率显著低于对照组pAdCMV-Link（－）转染组（P＜0．01），也低于pAdCMV-Linkl(CD)、pAdCMV-Linkl(tk）转染组（P＜0．05）。CD和5－FC、HSV－tk和GCV系统联合使用较单一自杀基因系统对HR－8348直肠癌细胞的集落形成、细胞生长有更显著的抑制作用，对肿瘤细胞有更强的杀伤能力和“旁观者效应”。结论 CD和HSV－tk双自杀基因联合作为肿瘤基因治疗的一种手段和方法，较单一自杀基因具有更强的抗肿瘤作用。

Antitumor effects of cytosine deaminase and HSV-tk double suicide gene with adenovirus mediation on rectal cancer cells

Objective To study antitumor effects of cytosine deaminase (CD) gene/5 fluorocytosine (5 FC) and herpes simplex virus thymidine kinase(HSV tk) gene/ganciclovir (GCV) systems on rectal cancer cells with adenovirus mediation. Methods CD and HSV tk double suicide genes were transinfected into HR 8348 rectal cacer cells with recombinant adenovirus mediation. The expression of CD and HSV tk genes was detected with RT PCR. Plating efficiency and MTT method were used to evaluate the antitumor effect of CD and 5 FC, HSV tk and GCV systems. Results Adenovirus was recombined with pAdCMV Link1(CD tk),pAdCMV Link1(-), pAdCMV Link1(CD), and pAdCMV Link1(tk) plasmids respectively. HR 8348 cells were infected with the recombined adenovirus and the high expression of CD and (or) HSV tk genes was found in the corresponding group of tumor cells. Before use of prodrug 5 FC and GCV, the plating efficiency and survival rate of the cells in each group were without significantly different ( P >0 05). But the plating efficiency and survival rate of the tumor cells in pAdCMV Link1(CD tk) transinfection group were more highly inhibited than in control, pAdCMV Link1(-) ( P <0 01)and single suicide gene transinfection groups ( P <0 05) after use of 5 FC and GCV. Combined of use CD and 5 FC, HSV tk and GCV systems remarkbly inhibited the plating efficiency and growth of tumor cells transinfected with double suicide genes. Conclution Transinfection of CD and HSV tk double suicide genes has a powerful antitumor effect.