Retroviral-mediated HSV-tk gene terapy on bladder cancdcer ex vivo and its hystander effect

HSV-TK gene was transferred into urine hladder cancer cell line T739 by retrovirus in vitro. Tumors were induced in syngneic mice by peritonum injection with different ratio of T739 and T739TK cells. At the same time, subcutaneous tumors in back were established with parent T739 cells. After 6 days administration of GCV tumor volume and survival time were investigated. Tumor growth was inhibited and mice surrvival time prolonged with higher TK gene gransfer ratio, when the ratio was above 50% subcutaneous tumor growth was also inhibited sinificantly. The effects of hsv-tk/gcv on bladder cancer is enhanced by igher gene transfer ratio and the didstant bystander effect is found.