[Effects of IL-18 gene transfection on the proliferation in vitro and tumorigenesis in vivo of mouse ovarian cancer cell line OVHM].

AIM: To investigate the effects of IL-18 gene transfection on proliferation, apoptosis and tumorigenesis of mouse ovarian cancer cell line OVHM. METHODS: OVHM were transfected with retrovirus encoding IL-18 gene (OVHM/IL-18). The wild OVHM and OVHM transfected with vector without IL-18 gene (OVHM/LXSN) were enrolled as the controls. The proliferation, cell cycle and apoptosis were measured by MTT and FCM respectively. The nude mice were subcutaneously inoculated with the three different cells respectively. The observation of transplanted tumor's growth and calculation of tumorigenesis ratio was made. The expression of IL-18 mRNA in tumor tissues was detected by RT-PCR, and the apoptosis of tumor cell in tissue was analyzed by electron microscope and FCM. RESULTS: The three cells cultured in vitro showed no apoptotic peaks, and no differences in proliferation and cell cycle (All P>0.05). Following inoculation, the ratios of tumorigenesis were similar in all the three groups. But in OVHM/IL-18 group, the latent period of tumorigenesis was longer with slower tumor growth rate and positive expression of IL-18 mRNA in tumor tissue. It was also observed that in the tumor cells from nude mice inoculated by OVHM/IL-18, the cells in phase of G0/G1 increased with typical morphology of apoptosis, and those in S phase decreased with decreased proliferation index and increased apoptosis index (All P<0h01). CONCLUSION: Although IL-18 gene has no cytotoxic effects in vitro, its inhibiting effects on tumorigenesis of OVHM in vivo were exerted by interdicting cell cycle and accelerating apoptosis of tumor cells.