Increased activation of cGAS-STING pathway enhances radiosensitivity of non-small cell lung cancer cells

Background Radiotherapy is an effective therapeutic approach widely used clinically in non-small cell lung cancer (NSCLC), but radioresistance remains a major challenge. New and effective radiosensitizing approaches are thus urgently needed. The activation of DNA-sensing cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has become an attractive therapeutic target, but the relationship between activation of cGAS-STING pathway and radiosensitization of NSCLC cells remains unknown. Methods Considering low expression of cGAS-STING pathway genes in NSCLC, including STING, we used an activator (STING agonist, dimeric amidobenzimidazole [diABZI]) of cGAS-STING pathway and increased activation factor (DNA double strand breaks) of cGAS-STING pathway to respectively reinforce the activation of cGAS-STING pathway in NSCLC cells. We then investigated the effect of increased activation of cGAS-STING pathway on the proliferation of H460 and A549 cells by CCK-8 and colony formation assays, and revealed the underlying mechanism. Results We found that both diABZI and the increased DNA double strand breaks could sensitize NSCLC cells to irradiation. Mechanically, our results showed that the increased activation of cGAS-STING pathway enhanced radiosensitivity by promoting apoptosis in NSCLC cells. Conclusion Taken together, we concluded that diABZI could be used as a radiosensitizer in NSCLC cells, and targeting the activation of cGAS-STING pathway has a potential to be a new approach for NSCLC radiosensitizing.