Enhancement of gene transfer efficiency into human cancer cells by modification of retroviral vectors and addition of chemicals

Retroviral vectors have recently experienced limited use in cancer gene the rapy mainly due to poor transduction efficiency. To overcome this drawback, we attempted to enhance the transduction efficiency by employing different retroviral packaging cell lines and chemical additives. The retrovirus fro m the PG13 packaging cell line gave mostly higher or similar transduction e fficiencies in a variety of human cancer cell lines compared to the retrovi rus from the PA317, Bing, or FLYRD18 packaging cell line. A cationic liposo me, especially Lipofectamine, significantly enhanced the transduction effic iency of a retrovirus. However, the retrovirus derived from the PG13 cell l ine could not infect the murine cell line efficiently even after Lipofectam ine treatment. Furthermore, chloroquine did not improve the transduction ef ficiency regardless of the presence of chemical additives. These results, t herefore, suggested that the transduction efficiency of a retrovirus in hum an cancer cells can certainly be improved when a proper packaging cell line is chosen. In addition, this study implied that Lipofectamine is a superb additive to enhance the transduction efficiency of a retrovirus via a speci fic virus envelope protein-receptor interaction for virus entry, and that r eceptor-mediated endocytosis does not seem to be the leading route of virus delivery to liberate a virus genome.