IN-VIVO TRANSFER OF A FOREIGN GENE TO KERATINOCYTES USING THE HEMAGGLUTINATING VIRUS OF JAPAN LIPOSOME METHOD

The hemagglutinating virus of Japan (HVJ)-liposome method involves the entrapment of DNA and nuclear protein within liposomes and the use of HVJ to enhance liposome fusion with cell membranes. This method has b een used successfully for in vivo gene transfer to various types of ti ssue, In this study, we investigated whether this method transfers gen es effectively to normal and malignantly transformed keratinocytes in vivo. We applied HVJ-liposome complex (HLC) containing the beta-galact osidase gene to the tape-stripped skin of hairless rats and detected t he enzyme activity in the keratinocytes of the treated skin. Compariso n of this method with the naked DNA injection method, which was shown recently to be useful for in vivo gene transfer to keratinocytes, demo nstrated that the transfer efficiency of the latter was about 5 times higher than that of the former. We assessed the efficacy of the HVJ-li posome method for gene transfer to transformed keratinocytes by examin ing the effect of HLC containing the herpes simplex virus thymidine ki nase gene on the growth of mouse squamous cell carcinomas. Local injec tion of HLC into the tumors followed by administration of ganciclovir to mice resulted in tumor growth inhibition. These results indicate th at the HVJ-liposome method is suitable for in vivo gene transfer to ke ratinocytes; also that this method may prove a good tool for basic res earch into keratinocyte biology and future keratinocyte gene therapy.