[Combination therapy of experimental murine hepatoma with mIL-12 gene and MHC I gene mediated by liposome].

BACKGROUND & OBJECTIVE: Interleukin-12 gene and MHC I gene have been used in gene therapy for cancer individually. To explore the synergistic antitumor effects of these two genes, the therapeutic effects of mIL-12 gene combined with MHC I (mouse H-2K) gene mediated by cationic liposome for experimental murine hepatoma were investigated. METHODS: Balb/C mouse liver cancer MM45T. Li cells were transfected with pcDNA3/mIL-12, pcDNA3/H-2Kb(H-2K of C57BL/6 mouse), and pcDNA3/GFP (reporter gene) mediated by lipofectAMINE 2000(LF 2000). The expressions of foreign genes in transfected cells were detected. Balb/C mice were inoculated subcutaneously with pcDNA3/mIL-12 and pcDNA3/H-2Kb transfected MM45T. Li. The tumorigenesis of the inoculated cells was detected. After intratumoral injection with LF2000-plasmid DNA complexes, the growth of murine tumor and the survival time of the tumor bearing mice were observated. RESULTS: The optimal ratio of LF2000: DNA is 3:1(microgram: microgram). The transfection efficiency reached to 30%. RT-PCR result showed the specific amplified fragments of the mIL-12 cDNA and H-2Kb cDNA in the transfected cells. Western blot analysis showed the expression of H-2Kb protein at 57 kDa. ELISA assay showed that the secretory mIL-12 was 48 ng/ml/10(6) cells. The tumorigenesis was decreased for transfected MM45T. Li cells with pcDNA3/mIL-12 and pcDNA3/H-2Kb. FACS assay showed that the numbers of CD3+, CD4+, and CD8+ cells from murine spleen were increased more in therapeutic group than in control group. The tumors grow slowly. The mIL-12 gene combined with H-2Kb gene has stronger antitumor effect for mouse liver cancer than single gene. CONCLUSION: The combination therapy with mIL-12 gene and MHC I gene mediated by LF-2000 have the positive synergistic antitumor effect for experimental murine hepatoma.