转TK基因的人结肠癌细胞对多种原药敏感性的研究

Human Colon Carcinoma Cells Transduced with TK Gene were Sensitive to Several Prodrugs

构建了含有单纯疱疹病毒胸苷激酶基因（HSV-TK）的重组逆转录病毒载体LTKSN．经PA317细胞包装后，感染人结肠癌细胞株LoVo．用G418筛选到稳定表达HSV-TK基因的细胞克隆LoVo／LTKSN．LoVo／LTKSN与野生型LoVo细胞相比，生长曲线无明显差异，细胞形态亦无改变．细胞毒试验证明LoVo／LTKSN对GCV的敏感性很高，半杀伤浓度IC50为0.5μmol/L，比野生型细胞提高了4000倍以上．三种不同的原药GCV，ACV和BVDU对LoLo／LTKSN具有效果不等的杀伤作用．BVDU和GCV联合作用效果更好．旁杀伤效果十分明显，低浓度GCV就可以将合10%LoVo／LTKSN的混合细胞中的大部分肿瘤细胞杀死．

Recombinant retroviral vector LTKSN containing herpes simplex virus thymidine kinase gene was constructed. After packaging into PA317 cell line,infectious particles were used to in feet human colon carcinoma cell line LoVo. Single clone harbouring HSV-TK gene was picked after G418 selection. There was no significant difference in cell growth curve or morphology between the LoVo/LTKSN and the wild type cells. But LoVo/LTKSN became 4 000 times more sensitive to the cytotoxicity of GCV(IC50= 0.5μmol/L)than LoVo. The three prodrugs GCV,ACV,BVDU when used separately showed different effect on LoVo/LTKSN and the combination of BVDU with GCV showed better effect. When LoVo/LTKSN cells were mixed with wild type LoVo cells at a ratio of 10: 90,significant bystander effect was observed in vitro after they were treated with nontoxic levels of GCV.