STING is part of the innate immune system, the body’s first line of response to foreign invaders. The protein is like a molecular fire alarm that is triggered by errant DNA signaling the presence of a bacterial or viral infection. Once STING is activated, it causes a cascade of molecular events that leads to inflammation.
Cancer companies want to intentionally trigger STING to spur inflammation in tumors, which may help recruit cancer-killing immune cells and boost the effectiveness of a popular class of immunotherapy drugs called checkpoint inhibitors. In some diseases, like STING-associated vasculopathy with onset in infancy (SAVI), a mutation in the protein itself can lead to perpetual STING activation and inflammation. In other diseases, like Aicardi-Goutières syndrome, mutations in DNA-degrading proteins lead to a buildup of DNA inside cells, triggering STING. There are instances where STING is activated by damaged cells releasing their own DNA.
