STING agonists in cancer immunotherapy: a brief review

The “STimulator of INterferon Genes” (STING) represents the primary sensors of cytosolic double-stranded DNA (dsDNA). The STING cellular signaling pathway is considered an attractive pharmacological target for cancer immunotherapy due to its immunostimulatory potential. In fact, activation of the intracellular STING protein triggers the secretion of type I IFNs, which results in immune-mediated tumor elimination and generation of antitumor immune memory. Two types of STING agonists were developed: cyclic dinucleotides (CDNs) and non-nucleotide small molecule agonists. Preclinical studies of STING agonists have demonstrated remarkable results in many tumor models, resulting in complete and durable therapeutic responses in a majority of treated mice. This review provides a brief summary of the latest research findings on STING agonists, their delivery to the tumor and the strategies being employed to enhance their efficacy in cancer immunotherapy.