title: Nuclear delivery of a therapeutic peptide by long circulating pH-sensitive liposomes: benefits over classical vesicles.
abstract: The purpose of this study is to propose a suitable vector combining increased circulation lifetime and intracellular delivery capacities for a therapeutic peptide. Long circulating classical liposomes [SPC:CHOL:PEG-750-DSPE (47:47:6 molar% ratio)] or pH-sensitive stealth liposomes [DOPE:CHEMS:CHOL:PEG(750)-DSPE (43:21:30:6 molar% ratio)] were used to deliver a therapeutic peptide to its nuclear site of action. The benefit of using stealth pH-sensitive liposomes was investigated and formulations were compared to classical liposomes in terms of size, shape, charge, encapsulation efficiency, stability and, most importantly, in terms of cellular uptake. Confocal microscopy and flow cytometry were used to evaluate the intracellular fate of liposomes themselves and of their hydrophilic encapsulated material. Cellular uptake of peptide-loaded liposomes was also investigated in three cell lines: Hs578t human epithelial cells from breast carcinoma, MDA-MB-231 human breast carcinoma cells and WI-26 human diploid lung fibroblast cells. The difference between formulations in terms of peptide delivery from the endosome to the cytoplasm and even to the nucleus was investigated as a function of time. Characterization studies showed that both formulations possess acceptable size, shape and encapsulation efficiency but cellular uptake studies showed the important benefit of the pH-sensitive formulation over the classical one, in spite of liposome PEGylation. Indeed, stealth pH-sensitive liposomes were able to deliver hydrophilic materials strongly to the cytoplasm. Most importantly, when encapsulated in pH-sensitive stealth liposomes, the peptide was able to reach the nucleus of tumorigenic and non tumorigenic breast cancer cells.
authors: Laboratory of Pharmaceutical Technology, CIRM, Department of Pharmacy, University of Liege, B36, Tour 4, Level 2, Avenue de l'hôpital, 1, B-4000 Liege, Belgium. Emilie.Ducat@ulg.ac.be
authors: E
authors: E
authors: Ducat
authors: J
authors: J
authors: Deprez
authors: A
authors: A
authors: Gillet
authors: A
authors: A
authors: Noël
authors: B
authors: B
authors: Evrard
authors: O
authors: O
authors: Peulen
authors: G
authors: G
authors: Piel
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives / Q000737:chemistry; D002460:Cell Line; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D002784:Cholesterol / Q000031:analogs & derivatives / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D005434:Flow Cytometry; D005452:Fluoresceins / Q000008:administration & dosage; D005456:Fluorescent Dyes / Q000008:administration & dosage; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000008:administration & dosage; D008081:Liposomes; D018613:Microscopy, Confocal; D010455:Peptides / Q000008:administration & dosage*; D011092:Polyethylene Glycols / Q000737:chemistry
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; D007211:Indoles; D008081:Liposomes; D010455:Peptides; D011092:Polyethylene Glycols; C007293:DAPI; C035784:N(1)-cholesterylcarbamoyl-N(8)-(4-nitrobenzo-2-oxa-1,3-diazole)-3,6-dioxaoctyl-1,8-diamine; D002784:Cholesterol; D009327:4-Chloro-7-nitrobenzofurazan; C007740:fluorexon