Improvements in gene therapy technologies.

We have combined hemagglutinating virus of Japan (HVJ; Sendai virus) with liposomes for efficient in vitro and in vivo fusion-mediated gene delivery. The HVJ-liposome was a highly efficient vehicle for the introduction of oligonucleotides into cells in vivo as well as for the transfer of genes <100 kbp without damaging cells. By coupling the Epstein-Barr (EB) virus replicon apparatus with HVJ-liposomes (virosomes), transgene expression was sustained in vitro and in vivo. When we added cationic lipids, the HVJ-cationic liposomes increased gene delivery 100 to 800 times in vitro compared with the conventional anionic virosomes and were also more useful for gene expression in restricted areas of organs and for gene therapy of disseminated cancers. We further discovered that the use of anionic virosomes with a virus-mimicking lipid composition (artificial viral envelope; AVE type) increased transfection efficiency approximately 10 fold in vivo, especially in the heart, liver, kidney, and muscle. Most animal organs were found to be suitable targets for the fusigenic virosomes, and numerous gene therapy strategies using this system were successful in animals. The combination of suicide gene therapy with radiation was very effective for killing hepatomas in a mouse model. Arteriosclerosis obliterans in animal models was cured by the transfer of hepatocyte growth factor.