생체계면활성제인 surfactin을 이용한 siRNA전달용 리포좀 제제화 연구

Abstract
Purpose: To investigate the use of cationic biosurfactant-containing liposomes as a delivery system of siRNA to cancer cells.
Methods: Cationic 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine (EDOPC)-based liposomes were formulated with various amounts of a biosurfactant, surfactin, ranging from 3 to 14 mole%. The extent of cellular siRNA delivery was determined by fluorescence microscopy and FACS analysis. The expression levels of the siRNA target gene were measured by reverse transcription polymerase chain reaction. Cell viability was examined using 3-(4,5-dimethylthiazole-2-yl)-2,5-di-phenyl tetrazolium bromide assay.
Results: Regardless of the liposomal composition, the size of the lipoplexes was not more than 200 nm, and the Zeta potential values were significantly reduced following complexation with siRNAs. When compared with surfactin-free liposomes, cationic surfactin liposomes showed enhanced cellular delivery of siRNA in Hela cells. More than 85% of the cells were positive for siRNA and following its delivery 14% of surfactin-containing liposomes. A survivin-specific siRNA that was delivered using surfactin-containing liposomes potently reduced the mRNA expression levels of the target gene in Hela cells. In contrast, survivin-specific siRNA delivered by surfactin-free EDOPC-based liposomes did not induce a significant reduction in mRNA levels. Moreover, cationic surfactin liposomes did not substantially reduce the cell viability. The treatment of luciferase-specific siRNA with 14% surfactin-containing liposomes showed more than 80% viability of the cells after 24 h of treatment.
Conclusion: These results suggest that cationic surfactin liposomes could be