cGAS is essential for the antitumor effect of immune checkpoint blockade

Hua Wang, Shuiqing Hu, Xiang Chen, Heping Shi, Chuo Chen, Lijun Sun, Zhijian J. Chen

Research output: Contribution to journalArticlepeer-review

311 Scopus citations


cGMP-AMP (cGAMP) synthase (cGAS) is a cytosolic DNA sensor that activates innate immune responses. cGAS catalyzes the synthesis of cGAMP, which functions as a second messenger that binds and activates the adaptor protein STING to induce type I interferons (IFNs) and other immune modulatory molecules. Here we show that cGAS is indispensable for the antitumor effect of immune checkpoint blockade in mice. Wild-type, but not cGAS-deficient, mice exhibited slower growth of B16 melanomas in response to a PD-L1 antibody treatment. Consistently, intramuscular delivery of cGAMP inhibited melanoma growth and prolonged the survival of the tumor-bearing mice. The combination of cGAMP and PD-L1 antibody exerted stronger antitumor effects than did either treatment alone. cGAMP treatment activated dendritic cells and enhanced cross-presentation of tumor-associated antigens to CD8 T cells. These results indicate that activation of the cGAS pathway is important for intrinsic antitumor immunity and that cGAMP may be used directly for cancer immunotherapy.

Original languageEnglish (US)
Pages (from-to)1637-1642
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number7
StatePublished - Feb 14 2017


  • Cancer
  • PD-L1
  • cGAMP
  • cGAS

ASJC Scopus subject areas

  • General


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