Experimental Study of the RV-HSV-TK/GCV Suicide Gene Therapy System in Cervix Cancer

Objective To study in vitro and in vivo killing effect and the bystander effect of HSV-TK/GCV suicide gene system on cervix cancer cell line Hela. Methods GINaTK retroviral vector containing HSV-TK gene was transduced into PA317 packaging cell by lipofectin. Cervix cancer cell line Hela was infected by high titer viral supernatant. Hela/TK cells and Hela cells were used in in vitro and in vim study. In in vitro study, sensitivity of Hela/TK cells to GCV and bystander effect were observed by MTT test. In in vivo study, Hela/TK cells and Hela cells were injected s.c. into flanking BALB/C mice, GCV was administrated i. p., RT-PCR was applied to detect the expression of HSV-TK gene. Statistical analysis of the data was performed by using the ANOVA(analysis of variance). Results The Hela cells transfered with GINaTK gene displayed a higher antitumor effect than parent cells. In in vitro study, when the ratio of Hela/TK cells reached 10%, the tumor cell-killing proportion was 50%. In in vim study, all mice developed tumors in 7 days after tumor cells implanted, the ratio of tumors formation was 100%. GCV could suppress tumor formation of the Hela/TK cells. After mice treated with GCV, the median tumor volume of mice implanted with Hela/TK cells and mice with cells mixed was decreased to 52.8% (P＜0.001) and 69.4% (P＜0.001) respectively compared with the control tumors. Their median survival was significantly prolonged (P＜0.001). Conclusion The test showed that the HSV-TK gene can be transducted into cervix cancer cell Hela under the mediation of retrovirus and be stable expressed, HSV-TK/GCV suicide gene therapy system could improve the antitumoral efficiency. The bystander effect could be observated in HSV-TK/GCV system in in vitro and in vivo.