title: Induction of cytotoxic T-lymphocytes and antitumor activity by a liposomal lipopeptide vaccine.
abstract: We have previously described a simple yet effective liposome-based therapeutic vaccine, DOTAP/E7, which contains only two molecules, the cationic lipid DOTAP and a peptide antigen derived from the E7 oncoprotein of human papillomavirus (HPV) type 16. In the current report, we have improved the vaccine formulation by incorporation of E7-lipopeptide instead of the water-soluble native E7 peptide into the DOTAP liposome. The lipopeptide consists of an N-terminal alpha- or -palmitoyl lysine connected to the E7 peptide via a dipeptide Ser-Ser linker. The DOTAP/E7-lipopeptide vaccine exhibited an enhanced functional antigen-specific CD8 (+) T lymphocyte response in vivo compared to the previous DOTAP/E7 formulation. More importantly, the cytotoxic T cells induced by the DOTAP/E7-lipopeptide vaccine could efficiently eliminate an existing HPV positive TC-1 tumor. The antitumor activity of lipopeptide formulated in DOTAP liposome was more than twice as potent as that of native E7, likely owing to the increased peptide entrapment efficiency in the liposomal complex. Our results also showed that it is essential to have the dipeptide spacer sequence between E7 peptide and the attached fatty acid to achieve a full immune response. Overall, the improved DOTAP/E7-lipopeptide vaccine described herein showed a significantly enhanced therapeutic effect for the treatment of a cervical cancer model.
authors.affiliation: Division of Molecular Pharmaceutics, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Weihsu
authors.initials: W
authors.lastname: Chen
authors.forename: Leaf
authors.initials: L
authors.lastname: Huang
mesh_terms: D000818:Animals; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology*; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D005229:Fatty Acids, Monounsaturated / Q000276:immunology; D005260:Female; D007150:Immunohistochemistry; D008055:Lipids / Q000276:immunology; D008081:Liposomes / Q000737:chemistry / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000628:therapy*; D009856:Oncogene Proteins, Viral / Q000276:immunology* / Q000378:metabolism; D050725:Papillomavirus E7 Proteins; D000644:Quaternary Ammonium Compounds / Q000276:immunology; D012097:Repressor Proteins / Q000276:immunology* / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D022223:Vaccines, Subunit
chemical_list: D019496:Cancer Vaccines; C068651:E6 protein, Human papillomavirus type 16; D005229:Fatty Acids, Monounsaturated; D008055:Lipids; D008081:Liposomes; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D000644:Quaternary Ammonium Compounds; D012097:Repressor Proteins; D022223:Vaccines, Subunit; C059731:oncogene protein E7, Human papillomavirus type 16; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane