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.
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.
Kang
Tae Heung
TH
Laboratory of Infection and Immunology, Graduate School of Medicine, Korea University, Ansan, Gyeonggi, Korea.
Lee
Jin Hyup
JH
Noh
Kyung Hee
KH
Han
Hee Dong
HD
Shin
Byung Cheol
BC
Choi
Eun Young
EY
Peng
Shiwen
S
Hung
Chien-Fu
CF
Wu
T-C
TC
Kim
Tae Woo
TW
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
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