[Basic research for interferon gene therapy against malignant glioma].

In order to establish new interferon therapy against malignant glioma by selective transfection of its gene, we developed a novel transfection system using liposomes bearing positive charges on their surface and entrapping plasmids containing the HuIFN- beta gene (pSV2IFN-beta). The liposomes were composed of N-(alpha -trimethylammonioacetyl) -didodecyl-D-glutamate chloride (TMAG), dilauroylphosphatidylcholine (DLPC), and dioleoylphosphatidylethanolamine (DOPE) as a molar ratio of 1:2:3. The liposomes were not observed to have cytotoxicity for human glioma cells, when applied at a rate less than 15nmol/ml. This liposome-mediated transfection of the gene into the cultured glioma cells (U-251-MG) resulted in the secretion of HuIFN- beta into the medium. The HuIFN- beta level in the culture media of glioma cells reached 23 IU/ml after 96h of incubation. When the pSV2IFN-beta containing liposomes were coupled with a monoclonal antibody (G-22 MCA) against glioma-associated antigen (G-22), the level of HuIFN-beta in the medium was 181 IU/ml, resulting in a 7-fold increase. It was indicated that this transfection system was a safe and selective method in the case of TMAG/DLPC/DOPE liposomes.