[HTML][HTML] ATR kinase inhibitor AZD6738 potentiates CD8+ T cell–dependent antitumor activity following radiation

FP Vendetti, P Karukonda, DA Clump… - The Journal of …, 2018 - Am Soc Clin Investig
FP Vendetti, P Karukonda, DA Clump, T Teo, R Lalonde, K Nugent, M Ballew, BF Kiesel…
The Journal of clinical investigation, 2018Am Soc Clin Investig
DNA-damaging chemotherapy and radiation therapy are integrated into the treatment
paradigm of the majority of cancer patients. Recently, immunotherapy that targets the
immunosuppressive interaction between programmed death 1 (PD-1) and its ligand PD-L1
has been approved for malignancies including non–small cell lung cancer, melanoma, and
head and neck squamous cell carcinoma. ATR is a DNA damage–signaling kinase activated
at damaged replication forks, and ATR kinase inhibitors potentiate the cytotoxicity of DNA …
DNA-damaging chemotherapy and radiation therapy are integrated into the treatment paradigm of the majority of cancer patients. Recently, immunotherapy that targets the immunosuppressive interaction between programmed death 1 (PD-1) and its ligand PD-L1 has been approved for malignancies including non–small cell lung cancer, melanoma, and head and neck squamous cell carcinoma. ATR is a DNA damage–signaling kinase activated at damaged replication forks, and ATR kinase inhibitors potentiate the cytotoxicity of DNA-damaging chemotherapies. We show here that the ATR kinase inhibitor AZD6738 combines with conformal radiation therapy to attenuate radiation-induced CD8+ T cell exhaustion and potentiate CD8+ T cell activity in mouse models of Kras-mutant cancer. Mechanistically, AZD6738 blocks radiation-induced PD-L1 upregulation on tumor cells and dramatically decreases the number of tumor-infiltrating Tregs. Remarkably, AZD6738 combines with conformal radiation therapy to generate immunologic memory in complete responder mice. Our work raises the possibility that a single pharmacologic agent may enhance the cytotoxic effects of radiation while concurrently potentiating radiation-induced antitumor immune responses.
The Journal of Clinical Investigation