Gene packaging with lipids, peptides and viruses inhibits transfection by electroporation in vitro.

To develop improved methods of gene delivery, packaging DNA in chemical or viral vectors could increase electroporation-mediated transfection. To test this hypothesis, electroporation was applied to DU145 prostate cancer cells incubated with green fluorescent protein-encoded DNA plasmid either naked or packaged with cationic lipid (Lipofectin), polycationic peptide (salmon protamine) or retroviral vectors (Moloney murine leukemia viruses) and then assayed for gene expression and cell viability. Cationic lipid or electroporation alone each significantly increased transfection, but their combination was less effective. Addition of protamine peptide during electroporation was also less effective than electroporation alone. The combination of retroviral vectors and electroporation transfected fewer cells than retrovirus alone. We conclude that the combination of electroporation with chemical or viral vectors does not improve gene transfection in vitro.