cGAS promotes sepsis in radiotherapy of cancer by up-regulating caspase-11 signaling.

Radiotherapy is the most common strategy in the treatment of cancer. However, radiation-induced acute complications, in particular sepsis, render patients in a life-threatening status or lead to delay of therapy that largely influences patients' overall responses. The understanding of sepsis in radiotherapy is currently scant and effective medicine is not available by far. Here, with WT mice as control, we challenged mice deficient to cGas, Caspase-11, Gsdmd or Asc with cecal ligation and puncture (CLP, a sepsis model) after a treatment of thorax irradiation. We found that radiation robustly upgraded caspase-11 pathway in irradiated region and consequently deteriorated lung injury and mortality in the sepsis model. cGas knockout markedly attenuated radiation-upgraded caspase-11 and restored sepsis. Deficiency of non-canonical inflammasome, caspase-11 and the downstream GSDMD, rather than an AIM2 inflammasome component, ASC, dramatically protected against radiation-promoted injury and mortality in septic mice. The protection may attribute to the inhibition of caspase-11-mediated pyroptosis in endothelial cells of the lung. Thus, blocking cGAS/caspase-11 signaling would be an adjuvant treatment strategy for preventing sepsis in radiotherapy of cancer.