Ligand-Tagged Cationic Liposome Facilitates Efficient Gene Delivery to Folate Receptors

Non-viral cationic liposome/DNA complexes (lipoplexes) have been used extensively in gene delivery approaches, although they have shown lower efficiency compared to viral carriers. In this study, a rational strategy was employed taking advantage of a combination of cationic liposomes prepared using the cationic cytofectin MSO9 and a folate ligand to create a more selective and effective gene delivery system to target cancer cells that overexpress the folate receptor (FR). The folate receptor-negative HEK293 (FR-), and folate receptor-positive HeLa (FR+) and KB (FR++) cell lines were employed to evaluate the efficiency of this novel gene delivery system under serum conditions. Folate was conjugated to the distal ends of DSPE-PEG₂₀₀₀ to create DSPE-PEG₂₀₀₀-FOL, which was then incorporated into the cationic liposomal bilayer. Our observations indicate that FA-labelled lipoplexes confer greater DNA protection, with PEGylated systems (liposome : pDNA) producing smallersized particles (<200 nm) ensuring appropriate pDNA release and targeted delivery. Moreover, FA-labelled lipoplexes attained higher transfection activity over nonfolate-labelled lipoplexes in FR-positive cell lines as confirmed by the luciferase and flow cytometry assays. Our results collectively highlight the potential of this lipid-based targeted gene delivery approach for future in vivo applications.