An experimental study on cervix cancer with combination of HSV-TK/GCV suicide gene therapy system and 60Co radiotherapy

Background: To evaluate the killing effect of HSV-TK/GCV suicide gene therapy system combined with Co-60 radiotherapy on human cervical cancer Hela cell line in vitro and in vivo, and to explore the radiosensitization by HSV-TK/GCV system. Methods: HSV-TK/GCV suicide gene therapy system and Co-60 radiotherapy were used separately or in combination on human cervical cancer Hela cell line in vitro and in vivo to compare their effects. Colony formation test and the rate of radiosensitization effect (E/O) were employed to observed the radiosensitization by HSV-TK/GCV system. Results: HSV-TK/GCV suicide gene therapy system had strong therapeutic effects on Hela cells in vitro and in vivo (the inhibition rates were 45.8% and 39.5%, respectively), moreover, the combined administration of gene therapy and radiotherapy had stronger therapeutic effects in vitro and in vivo (the inhibition rate was 87.5% in vitro, and the inhibition rate was 87.9% in vivo) (P < 0.01). The inhibition rate by radiotherapy alone was 42.4% in vitro and 35.8% in vivo. The sensitivity of combined therapy to radiotherapy increased more than that of therapy alone, the ability of colony formation decreased (P < 0.01). The rate of radiosensitivity effect (E/O) was 3.17(> 1.4), indicating HSV-TK/GCV system could exert a sensitizing effect on Co-60 radiotherapy of the transplanted human cervical cancer cell in nude mice. Conclusion: HSV-TK/GCV system had radiosensitization. Gene therapy combined with radiotherapy may be a good supplementary method for cervix cancer synthetic treatment.