American Association for Cancer Research
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Figure S2 from Radiotherapy Combined with Novel STING-Targeting Oligonucleotides Results in Regression of Established Tumors

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posted on 2023-03-30, 23:27 authored by Jason R. Baird, David Friedman, Benjamin Cottam, Thomas W. Dubensky, David B. Kanne, Shelly Bambina, Keith Bahjat, Marka R. Crittenden, Michael J. Gough

Figure S2. Role of T cells in local control by RR-CDG alone



Cytotoxic therapies prime adaptive immune responses to cancer by stimulating the release of tumor-associated antigens. However, the tumor microenvironment into which these antigens are released is typically immunosuppressed, blunting the ability to initiate immune responses. Recently, activation of the DNA sensor molecule STING by cyclic dinucleotides was shown to stimulate infection-related inflammatory pathways in tumors. In this study, we report that the inflammatory pathways activated by STING ligands generate a powerful adjuvant activity for enhancing adaptive immune responses to tumor antigens released by radiotherapy. In a murine model of pancreatic cancer, we showed that combining CT-guided radiotherapy with a novel ligand of murine and human STING could synergize to control local and distant tumors. Mechanistic investigations revealed T-cell–independent and TNFα-dependent hemorrhagic necrosis at early times, followed by later CD8 T-cell–dependent control of residual disease. Clinically, STING was found to be expressed extensively in human pancreatic tumor and stromal cells. Our findings suggest that this novel STING ligand could offer a potent adjuvant for leveraging radiotherapeutic management of pancreatic cancer. Cancer Res; 76(1); 50–61. ©2015 AACR.