Gene therapy of HSV-TK transferred by the EBV based expression vector on experimental hepatocellular carcinoma

To study the therapeutic effects of herpes simplex virus thymidine kinase (HSV-TK) gene transferred by the EBV-based expression vector (pDR2) on experimental hepatocellular carcinoma, pDR2-TK gene was delivered into human hepatocellular carcinoma cell line SMMC-7721 by using liposome-mediated transfection technique, and then gene expression was detected by RT-PCR, and the killing effects were examined through MTT method. In the nude mice hepatoma model, the antitumor effects of pDR2-TK/GCV system was evaluated in terms of tumor growth. MTT results showed that the pDR2-TK/GCV had cytotoxic effect and about 70% SMMC-7721 cells were killed when GCV was at 1000 mumol/L. In vivo experiment showed that the tumor size in nude mice with transferred pDR2-TK gene was significantly smaller than that in control group (P < 0.01). On the 10th day the tumor in 3 mice (60%) disappeared completely after GCV treatment. It is concluded that the pDR2-TK/GCV system has marked killing effects on the experimental hepatocellular carcinoma.