Inhibition of TC-1 Tumor Progression by Cotransfection of Saxatilin and IL-12 Genes Mediated by Lipofection or Electroporation

Recently, a number of reports have demonstrated that coexpression of therapeutic genes having different anticancer mechanisms is a more effective strategy for anticancer gene therapy than single gene expression. Saxatilin, a novel disintegrin from snake venom, has recently been shown to have potent antiangiogenic functions, such as inhibition of platelet aggregation, bFGF-induced proliferation of HUVEC, and vitronectin-induced smooth muscle cell migration. IL-12 is a well-known immune modulator that promotes Thl-type antitumor immune responses and inhibits angiogenesis as well. The saxatilin and/or IL-12 genes were transfected intratumorally into C57BL/6 mice carrying TC-1 transformed mouse lung endothelial cells by either lipofection or electroporation. The plasmids encoding saxatilin and IL-12 were administered to tumor tissues via novel cationic liposomes consisting of dimyristyl-glutamyl-lysine (DMKE). On the other hand, expression of the genes was also induced by electroporation after naked pDNA injection to the tumor tissues. Lipofection of saxatilin and/or IL-12 genes appeared to be slightly more effective in inhibition of tumor growth than electroporation of the same genes. Cotransfection of saxatilin and IL-12 genes was clearly more effective than individual administration of either gene. This result implies that cotransfection of saxatilin and IL-12 genes represents an innovative modality for anticancer gene therapy.