title: Attenuated expression of A20 markedly increases the efficacy of double-stranded RNA-activated dendritic cells as an anti-cancer vaccine.
abstract: A20 is a zinc finger protein with ubiquitin-modifying activity. A20 has been described as negatively regulating signaling induced by the TNF receptor and TLR family in a number of cell types, including mouse bone marrow-derived dendritic cells (DCs). However, the expression and effect of A20 in activated human monocyte-derived DCs have not been previously evaluated. We report that DCs activated with the TLR3 ligand poly(I:C) up-regulate A20. Down-regulating A20 demonstrated its role in the functional activation of DCs. A20 down-regulated DCs showed higher activation of the transcription factors NF-kappaB and activator protein-1, which resulted in increased and sustained production of IL-6, IL-10, and IL-12p70. We additionally silenced the immunosuppressive cytokine IL-10 and demonstrated that IL-10 inhibits T cell proliferation. We further demonstrated that A20 down-regulated DCs skew naive CD4+ T cells toward IFN-gamma producing Th1 cells, a process which is dependent on IL-12p70 and which is unaffected by IL-10. Furthermore, A20 and/or IL-10 down-regulated DCs had an enhanced capacity to prime Melan-A/MART-1 specific CD8+ T cells. Finally, we demonstrated that potent T cell stimulatory DCs are generated by the simultaneous delivery of poly(I:C12U), A20, or A20/IL-10 small interfering RNA and Ag-encoding mRNA, introducing a one step approach to improve DC-based vaccines. Together these findings demonstrate that A20 negatively regulates NF-kappaB and activator protein-1 in DCs and that down-regulation of A20 results in DCs with enhanced T cell stimulatory capacity.
authors.affiliation: Laboratory of Molecular and Cellular Therapy, Department of Physiology-Immunology, Medical School of the Vrije Universiteit Brussel, Brussels, Belgium. karine.breckpot@vub.ac.be
authors.forename: Karine
authors.initials: K
authors.lastname: Breckpot
authors.forename: Cindy
authors.initials: C
authors.lastname: Aerts-Toegaert
authors.forename: Carlo
authors.initials: C
authors.lastname: Heirman
authors.forename: Uschi
authors.initials: U
authors.lastname: Peeters
authors.forename: Rudi
authors.initials: R
authors.lastname: Beyaert
authors.forename: Joeri L
authors.initials: JL
authors.lastname: Aerts
authors.forename: Kris
authors.initials: K
authors.lastname: Thielemans
mesh_terms: D000276:Adjuvants, Immunologic / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000235:genetics* / Q000276:immunology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D004268:DNA-Binding Proteins; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism / Q000637:transplantation*; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology*; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis; D018664:Interleukin-12 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D034622:RNA Interference / Q000276:immunology; D012330:RNA, Double-Stranded / Q000502:physiology*; D034741:RNA, Small Interfering / Q000502:physiology; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D019496:Cancer Vaccines; D004268:DNA-Binding Proteins; D015850:Interleukin-6; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D018808:Transcription Factor AP-1; D016753:Interleukin-10; D018664:Interleukin-12; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3