Development of glycyrrhetinic acid-modified stealth cationic liposomes for gene delivery

The glycyrrhetinic acid-modified stealth cationic liposomes (GA–PEG–CLs) loaded with pDNA (GA–PEG–CLPs) were developed and found to transfect human hepatocellular carcinoma cell line HepG2 with high efficiency. GA–PEG–CLs were comprised of DOTAP, cholesterol (Chol) and glycyrrhetinic acid–polyethyleneglycol–cholesterol conjugate (GA–PEG–Chol). Agarose gel electrophoresis revealed that 5% GA–PEG–CLs constituted by DOTAP/Chol/GA–PEG–Chol at molar ratio of 50:45:5 could completely entrap pDNA at a lower liposomes/pDNA weight ratios of 4:1 (N/P ratio: 1.14). Compared to ordinary cationic liposomes (CLs), steric cationic liposomes (PEG–CLs) and 1% GA–PEG–CLs made from DOTAP/Chol/MPEG2000-Chol/GA–PEG–Chol at molar ratio of 50:45:4:1, 5% GA–PEG–CLs were found to possess the highest transfection efficiency as gene vectors in serum-free or serum-containing medium in PKCα over-expressed HepG2 cells but no significance difference in human embryonic kidney cell line HEK 293. Additionally, 5% GA–PEG–CLs have the lowest cytotoxicity on human normal hepatocyte cell line L02. The competitive inhibition experiments mediated by GA were carried out in HepG2 cells, which demonstrated that GA–PEG–CLs could deliver selectively pDNA to hepatoma cells by the targeting moiety GA. In conclusion, GA–PEG–CLs containing 5% GA–PEG–Chol might be one of the most potential gene vectors as hepatoma targeting therapy.