Influence of lipid components on gene delivery by polycation liposomes: Transfection efficiency, intracellular kinetics and in vivo tumor inhibition.

Transfection efficiency of non-viral gene vectors is influenced by many factors, including chemical makeup, cellular uptake pathway and intracellular delivery. To investigate the effect of lipid saturation on transfection efficiency of polycation liposomes (PCLs), a soybean phospholipids (SPL), egg phospholipids (EPL) and hydrogenated soybean phosphatidylcholine (HSPC) series was used to prepare PCLs. Testing these PCLs in a luciferase assay indicated that with increasing saturation (SPL<EPL<HSPC), the ability to confer gene expression decreased. The effect of protamine combined with these PCLs was also studied in different cell lines. Improved transfection because of protamine incorporation was dependent on lipid saturation and on the cell line tested. The kinetics of cellular uptake and intracellular distribution was studied using flow cytometry and laser scanning confocal microscope, which showed that naked oligonucleotide (ODN) and PCLs/ODN complexes became equilibrium after 4h incubation. PCLs containing SPL (PCLs-S) and 1,2-dieleoyl-sn-glycero-3-phosphoethanolamine (PCLs-D) increased uptake rates by 2.20- and 5.45-fold, respectively. Furthermore, pCMV-IL-12 transfection mediated by PCLs-D showed excellent tumor inhibition efficiency compared with control and naked pCMV-IL-12 treatments in vivo.