Abstract
Ionizing radiation-mediated tumor regression depends on type I interferon (IFN) and the adaptive immune response, but several pathways control I IFN induction. Here, we demonstrate that adaptor protein STING, but not MyD88, is required for type I IFN-dependent antitumor effects of radiation. In dendritic cells (DCs), STING was required for IFN-? induction in response to irradiated-tumor cells. The cytosolic DNA sensor cyclic GMP-AMP (cGAMP) synthase (cGAS) mediated sensing of irradiated-tumor cells in DCs. Moreover, STING was essential for radiation-induced adaptive immune responses, which relied on type I IFN signaling on DCs. Exogenous IFN-? treatment rescued the cross-priming by cGAS or STING-deficient DCs. Accordingly, activation of STING by a second messenger cGAMP administration enhanced antitumor immunity induced by radiation. Thus radiation-mediated antitumor immunity in immunogenic tumors requires a functional cytosolic DNA-sensing pathway and suggests that cGAMP treatment might provide a new strategy to improve radiotherapy.
Copyright © 2014 Elsevier Inc. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptive Immunity
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Adaptor Proteins, Vesicular Transport / genetics
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Animals
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Antineoplastic Agents / pharmacology
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Cells, Cultured
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Cross-Priming / immunology
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DNA / immunology*
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Dendritic Cells / immunology
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Immunity, Innate
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Interferon-beta / biosynthesis
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Interferon-beta / immunology
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Interferon-beta / pharmacology
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Membrane Proteins / genetics*
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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Myeloid Differentiation Factor 88 / genetics
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Neoplasms / immunology
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Neoplasms / radiotherapy*
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Nucleotides, Cyclic / pharmacology
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Nucleotidyltransferases / immunology*
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RNA Interference
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RNA, Small Interfering
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Radiation, Ionizing
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Receptor, Interferon alpha-beta / genetics
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Receptor, Interferon alpha-beta / immunology
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Signal Transduction / immunology
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Xanthones / pharmacology
Substances
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Adaptor Proteins, Vesicular Transport
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Antineoplastic Agents
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Ifnar1 protein, mouse
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Membrane Proteins
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Myd88 protein, mouse
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Myeloid Differentiation Factor 88
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Nucleotides, Cyclic
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RNA, Small Interfering
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Sting1 protein, mouse
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TICAM-1 protein, mouse
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Xanthones
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cyclic guanosine monophosphate-adenosine monophosphate
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vadimezan
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Receptor, Interferon alpha-beta
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Interferon-beta
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DNA
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Nucleotidyltransferases
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cGAS protein, mouse