title: Exosome-based tumor antigens-adjuvant co-delivery utilizing genetically engineered tumor cell-derived exosomes with immunostimulatory CpG DNA.
abstract: For cancer immunotherapy via tumor antigen vaccination in combination with an adjuvant, major challenges include the identification of a particular tumor antigen and efficient delivery of the antigen as well as adjuvant to antigen-presenting cells. In this study, we proposed an efficient exosome-based tumor antigens-adjuvant co-delivery system using genetically engineered tumor cell-derived exosomes containing endogenous tumor antigens and immunostimulatory CpG DNA. Murine melanoma B16BL6 cells were transfected with a plasmid vector encoding a fusion streptavidin (SAV; a protein that binds to biotin with high affinity)-lactadherin (LA; an exosome-tropic protein) protein, yielding genetically engineered SAV-LA-expressing exosomes (SAV-exo). SAV-exo were combined with biotinylated CpG DNA to prepare CpG DNA-modified exosomes (CpG-SAV-exo). Fluorescent microscopic observation revealed the successful modification of exosomes with CpG DNA by SAV-biotin interaction. CpG-SAV-exo showed efficient and simultaneous delivery of exosomes with CpG DNA to murine dendritic DC2.4 cells in culture. Treatment with CpG-SAV-exo effectively activated DC2.4 cells and enhanced tumor antigen presentation capacity. Immunization with CpG-SAV-exo exhibited stronger in vivo antitumor effects in B16BL6 tumor-bearing mice than simple co-administration of exosomes and CpG DNA. Thus, genetically engineered CpG-SAV-exo is an effective exosome-based tumor antigens-adjuvant co-delivery system that will be useful for cancer immunotherapy.
authors.affiliation: Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Morishita
authors.affiliation: Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan. Electronic address: ytakahashi@pharm.kyoto-u.ac.jp.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Matsumoto
authors.affiliation: Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Makiya
authors.initials: M
authors.lastname: Nishikawa
authors.affiliation: Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Takakura
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage* / Q000235:genetics; D000818:Animals; D000951:Antigens, Neoplasm / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology*; D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics; D004247:DNA / Q000235:genetics*; D004338:Drug Combinations; D055354:Exosomes / Q000235:genetics / Q000276:immunology*; D005818:Genetic Engineering / Q000379:methods*; D007114:Immunization / Q000379:methods; D007167:Immunotherapy / Q000379:methods; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000235:genetics / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm; D004338:Drug Combinations; D004247:DNA
keywords: Cancer vaccine; CpG DNA; Drug delivery; Exosomes; Genetic engineering; Tumor antigens