SR-717 free acid is a stable cGAMP mimetic and non-nucleotide STING agonist, demonstrating antitumor activity with EC50 values of 2.1 μM in ISG-THP1 (WT) and 2.2 μM in ISG-THP1 cGAS KO (cGAS KO) cell lines.

SR-717 functions as a STING activator, triggering a closed conformation that opens pathways for investigating its role as a systemic STING agonist across various contexts, including enhancing antitumor immunity. Specifically, at a concentration of 3.8 μM, SR-717 promotes PD-L1 expression in both THP1 cells and primary human peripheral blood mononuclear cells, dependent on the STING pathway.

SR-717, administered at a dosage of 30 mg/kg intraperitoneally once per day for one week, exhibits antitumor activities in both WT or Sting gt/gt mice [1]. This compound not only demonstrates significant antitumor activity, but also enhances the activation of CD8+ T cells, natural killer cells, and dendritic cells within pertinent tissues, aiding in antigen cross-priming. The administration of SR-717 under the specified conditions resulted in the maximal inhibition of tumor growth, underscoring its potential therapeutic efficacy in cancer models [1].