title: Enhancing dendritic cell vaccine potency by combining a BAK/BAX siRNA-mediated antiapoptotic strategy to prolong dendritic cell life with an intracellular strategy to target antigen to lysosomal compartments.
abstract: Dendritic cell (DC)-based vaccines have become important in immunotherapeutics as a measure for generating antitumor immune responses. We have previously demonstrated that linkage of the antigen gene to a lysosomal targeting signal, a sorting signal of the lysosome-associated membrane protein type 1 (LAMP-1), enhances the potency of DC-based vaccines. DCs have a limited life span, hindering their long-term ability to prime antigen-specific T cells. In this study, we attempted to further improve the potency of a DC vaccine that targets human papilloma virus 16 (HPV16) E7 to a lysosomal compartment (DC-Sig/E7/LAMP-1) by combining a strategy to prolong DC life. We show that small interfering RNA-targeting Bak and Bax proteins can be used to allow transfected DCs to resist being killed by T cells. This is done by downregulating these proapoptotic proteins, which have been known as so-called gate keepers in mitochondria-mediated apoptosis. DCs expressing intact E7 or Sig/E7/LAMP-1 became resistant to attack by CD8+ T cells after transfection with BAK/BAX siRNA, leading to enhanced E7-specific T cell activation in vitro and in vivo. More importantly, vaccination with E7-presenting DCs transfected with BAK/BAX siRNA generated a strong therapeutic effect against an E7-expressing tumor in vaccinated mice, compared with DCs transfected with control siRNA. Our data indicate that a combination of strategies to enhance intracellular Ag processing and to prolong DC life may offer a promising strategy for improving DC vaccine potency.
authors.affiliation: Laboratory of Infection and Immunology, Graduate School of Medicine, Korea University, Ansan, Gyeonggi, Korea.
authors.forename: Tae Heung
authors.initials: TH
authors.lastname: Kang
authors.forename: Jin Hyup
authors.initials: JH
authors.lastname: Lee
authors.forename: Kyung Hee
authors.initials: KH
authors.lastname: Noh
authors.forename: Hee Dong
authors.initials: HD
authors.lastname: Han
authors.forename: Byung Cheol
authors.initials: BC
authors.lastname: Shin
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Shiwen
authors.initials: S
authors.lastname: Peng
authors.forename: Chien-Fu
authors.initials: CF
authors.lastname: Hung
authors.forename: T-C
authors.initials: TC
authors.lastname: Wu
authors.forename: Tae Woo
authors.initials: TW
authors.lastname: Kim
mesh_terms: D000818:Animals; D017209:Apoptosis; D018414:CD8-Positive T-Lymphocytes; D019496:Cancer Vaccines / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology*; D015536:Down-Regulation; D006801:Humans; D051907:Lysosomal Membrane Proteins / Q000235:genetics / Q000276:immunology; D008247:Lysosomes / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology; D050725:Papillomavirus E7 Proteins; D034741:RNA, Small Interfering / Q000502:physiology*; D013602:T-Lymphocytes, Cytotoxic; D014162:Transfection; D014611:Vaccination; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000235:genetics* / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics* / Q000378:metabolism; D052118:Lysosomal-Associated Membrane Protein 1
chemical_list: D019496:Cancer Vaccines; D051907:Lysosomal Membrane Proteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D034741:RNA, Small Interfering; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; C494773:Bak1 protein, mouse; C494827:Bax protein, mouse; C052255:Lamp1 protein, mouse; D052118:Lysosomal-Associated Membrane Protein 1; C059731:oncogene protein E7, Human papillomavirus type 16