Efficient gene transfer to EGF receptor overexpressing cancer cells by means of EGF-labeled cationic liposomes.

Epidermal growth factor (EGF)-labeled cationic liposomes (EGF-liposomes) were prepared for efficient gene transfer vector to EGF receptor expressing cells. Transfection activity of EGF-liposomes associating plasmid PGV-C which encodes luciferase showed a 2-fold increase in EGF receptor expressing cells, HEC-1-A, compared to that of EGF-non-labeled liposomes (N-liposomes). In EGF receptor deficient HRA cells, however, both EGF- and N-liposomes exhibited low transfection efficiency and no difference was observed between them. Furthermore, by the addition of anti EGF receptor antibody, transfection efficiency of EGF-liposomes was suppressed, suggesting EGF receptor-mediated endocytosis of EGF-liposomes. Transfection activity of EGF-liposomes was strongly dependent on the concentrations of fusogenic lipid, dioleoylphospha-tidylethanolamine in liposomes. By X-gal staining 6-8% of GCH-1(m) cells which also had EGF receptor expressed beta-galactosidase activity following the transfection by EGF-liposomes associating pSV-beta-galactosidase. These findings indicate that EGF-liposomes could be a preferable vector for EGF-receptor expressing cells.