title: Enhanced heparan sulfate proteoglycan-mediated uptake of cell-penetrating peptide-modified liposomes.
abstract: Protein transduction domains (PTDs) are used to enhance cellular uptake of drugs, proteins, polynucleotides or liposomes. In this study, functionalized Antennapedia (Antp, aa 43-58) and HIV Tat (aa 47-57) peptides were coupled to small unilamellar liposomes via thiol-maleimide linkage. Modified liposomes showed higher uptake into a panel of cell lines including tumor and dendritic cells than unmodified control liposomes. Liposome uptake was time and concentration dependent as analyzed by flow cytometry and live-cell microscopy. At least 100 PTD molecules per small unilamellar liposome (100 +/- 30 nm) were necessary for efficient translocation into cells. Cellular uptake of PTD-modified liposomes was 15- to 25-fold increased compared to unmodified liposomes and was inhibited by preincubation of liposomes with heparin. Glycosaminoglycan-deficient CHO cells showed dramatically reduced cell association of PTD-modified liposomes, confirming the important role of heparan sulfate proteoglycans in PTD-mediated uptake. Antp-liposomes used as carriers of the cytotoxic drug N4-octadecyl-1-beta-D-arabinofuranosylcytosine-(5'- 5')-3'-C-ethinylcytidine showed a reduction of the IC50 by 70% on B16F1 melanoma cells compared with unmodified liposomes. PTD-functionalized liposomes, particularly Antp-liposomes, represent an interesting novel carrier system for enhanced cell-specific delivery of a large variety of liposome-entrapped molecules.
authors.affiliation: Paul Scherrer Institut, Biomolecular Research, Molecular Cell Biology, 5232, Villingen-PSI, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Marty
authors.forename: C
authors.initials: C
authors.lastname: Meylan
authors.forename: H
authors.initials: H
authors.lastname: Schott
authors.forename: K
authors.initials: K
authors.lastname: Ballmer-Hofer
authors.forename: R A
authors.initials: RA
authors.lastname: Schwendener
mesh_terms: D000818:Animals; D005434:Flow Cytometry; D006367:HeLa Cells; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006801:Humans; D008081:Liposomes / Q000378:metabolism* / Q000633:toxicity; D051379:Mice; D008856:Microscopy, Fluorescence; D010455:Peptides / Q000378:metabolism*
chemical_list: D019812:Heparan Sulfate Proteoglycans; D008081:Liposomes; D010455:Peptides