Receptor-mediated gene transfer to cells of hepatic origin by galactosylated albumin-polylysine complexes.

To study whether we could enhance the liver targeting of DNA delivery via asialoglycoprotein receptors using a complex of poly-L-lysine (PLL)-condensed DNA and galactosylated bovine serum albumin (GalBSA) (GPD complex), DNA was first combined with PLL and then with GalBSA via charge interaction (GalBSA: PLL: DNA=3:0.5:1, w/w/w). This vector was characterized by dynamic laser light scattering, gel retardation assay, and electron microscopy to determine the particle size, electrostatic charge interaction, and 3-D structure. An electron micrography of GPD complex, where GalBSA: PLL: DNA=3:0.5:1 (w/w/w), showed a structure of spherical particles with a mean diameter of 145+/-24.2 nm, and the complex was positively charged. The complex was tested for specificity and efficiency of gene transfer in cultured human hepatoblastoma cell line Hep G2 and mouse fibroblast cells NIH/3T3 in vitro. Cellular uptake was specifically dependent on the abundance of galactose receptors on target cells. Hep G2 cells transfected with GPD complexed with the fusogenic peptide KALA (WEAKLAKALAKALAKHLAKALAKALKACEA) showed a significantly higher reporter gene activity than those transfected with GPD complex alone or free DNA-KALA complex. The efficiency of gene transfer mediated by GPD-KALA complex was not affected by the presence of serum in the transfection medium. The reporter gene activity in NIH/3T3 cells transfected with GPD complex was very low regardless of the presence of KALA and almost the same as that transfected with bovine serum albumin (BSA)-PLL-DNA complex (BPD complex). This gene transfer formulation may find potential applications for the gene therapy of liver diseases.