Efficiency of liposomes surface-modified with soybean-derived sterylglucoside as a liver targeting carrier in HepG2 cells

We investigated the interaction of liposomes surface-modified with soybean-derived sterylglucoside (SG) (SG-liposomes) with HepG2 cells in the point of involvement of asialoglycoprotein receptor (ASGP-R) mediated endocytosis and examined the efficiency of SG-liposomes as drug carriers using 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) as a maker of liposome, carboxylated polystyrene microspheres (Fluoresbrite) as a model drug not taken up in cells and doxorubicin (DXR). SG-liposomes were composed of dipalmitoylphosphatidylcholine (DPPC), cholesterol (Ch) and SG (DPPC/Ch/SG=6:3:1, molar ratio) and DiI, Fluoresbrite and DXR were entrapped in SG-liposomes, respectively. Each SG-liposome was incubated with HepG2 cells at 4 or 37°C, and co-incubated with asialofetuin (AF) as a competitor of ASGP-R. The association of DiI, Fluoresbrite or DXR entrapped in SG-liposomes with HepG2 cells at 37°C was significantly higher than that in liposomes containing no SG. That of DiI and Fluoresbrite was reduced significantly by the incubation with AF, but that of DXR was not affected. These findings suggest that Fluoresbrite behaves like the lipid component of SG-liposomes, but DXR in SG-liposomes does not behave similar to the lipid component of SG-liposomes, thus, its drug behavior released from liposomes may be due to its physicochemical properties. SG-liposomes are potentially useful drug carriers to the liver, because the glucose residue may work as a kind of ligand for ASGP-R.