OBJECTIVETo investigate the effects of matrine on the anti-tumor efficiency of H22 murine hepatocarcinoma cell-based vaccine modified by TIM2 gene in vivo.

METHODThe combinant eukaryotic expression vector pIRES2-EGFP-TIM2 was constructed and transfected into H22 cells by lipofectamin. The monoclone of the positive H22-TIM2 cells and negative control H22-EGFP cells were selected by G418 pressure and limited dilution method in turn. The H22 whole-cell-based vaccine were inoculated to establish the tumor-bearing mouse model, and its oncogenicity and immunogenicity were observed in vivo. Then the matrine was administered to the tumor-bearing mice inoculated by H22-TIM2 cells, H22-EGFP cells and H22 cells, and the inhibitory effect of matrine on tumor was studied.

RESULTThe co-expression of EGFP protein and TIM2 mRNA were detected in H22-TIM2 cells. The rate of tumor formation in mice injected of H22-TIM2 cells was 41%, lower than that of H22 cells and H22-EGFP cells injection (92%) in mice. The growth of tumor were significantly inhibited vaccinated with H22-TIM2 cells in mice. The inhibitory rate of tumor (IR) was 69.2% in mice of H22-TIM2 group, higher than that of mice treated with matrine and H22 cells injection, the later was 67.5%. Matrine could dramatically strengthen the anti-tumor efficiency of H22 cells modified by TIM2 gene, with the highest tumor inhibitory rate (IR) (90.6%) in all the experimental mice. The spleen index, populations of CD4-positive lymphocytes and the ratio of CD4-positive to CD8-positive lymphocytes of spleen in mice vaccinated of H22-TIM2 cells were obviously higher than those in the other groups.

CONCLUSIONThe oncogenicity of H22 cells is markedly impaired after modified by TIM2 gene. Matrine can strengthen the inhibitory effect of H22-TIM2 cells on tumor in mice. These data give us important clues to further study the biological role of TIM2 gene in tumor immunity and explore the molecular mechanism of matrine in suppressing tumor.