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 a sialoglycoprotein receptors using a complex of poly-L-lysine (PLL)-condense d DNA and galactosylated bovine serum albumin (GalBSA) (GPD complex), DNA w as first combined with PLL and then with GalBSA via charge interaction (Gal BSA : PLL : DNA=3 : 0.5 : 1, w/w/w). This vector was characterized by dynam ic laser light scattering, gel retardation assay, and electron microscopy t o determine the particle size, electrostatic charge interaction, and 3-D st ructure. 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 d iameter of 145+/-24.2 nm, and the complex was positively charged, The compl ex was tested for specificity and efficiency of gene transfer in cultured h uman hepatoblastoma cell line Hep G2 and mouse fibroblast cells NIH/3T3 in vitro. Cellular uptake was specifically dependent on the abundance of galac tose receptors on target cells. Hep G2 cells transfected with CPD complexed with the fusogenic peptide KALA (WEAKLAKLAKLAKHLAKALAKALKACEA) showed a si gnificantly higher reporter gene activity than those transfected with GPD c omplex alone or free DNA-KALA complex. The efficiency of gene transfer medi ated by GPD-KALA complex,vas not affected by the presence of serum in the t ransfection medical, The reporter gene activity in NIH/3T3 cells transfecte d with GPD complex was very low regardless of the presence of KALA and almo st the same as that transfected with bovine serum albumin (BSA)-PLL-DNA com plex (BPD complex). This gene transfer formulation may find potential appli cations for the gene therapy of liver diseases.