Enpp-1-IN-27 is a selective ENPP1 inhibitor with an IC50 of 14.68 nM, exhibiting approximately 410-fold selectivity over ENPP2 and roughly 10-fold selectivity over ENPP3. This compound stabilizes cGAMP levels and activates the STING pathway, leading to cytokine release and an enhanced innate immune response. In addition, Enpp-1-IN-27 activates ISRE and boosts cGAMP-mediated immune responses, demonstrating significant antitumor effects in 4T1 and CT26 syngeneic mouse models. It is applicable to breast cancer and colon cancer research.

Enpp-1-IN-27 (Compound 31) enhances cGAMP-mediated STING activity in THP-1 cells (EC50 = 16.5 μM) and HCT116 cells more effectively than cGAMP alone at concentrations of 0-50 μM over a period of 25 hours. It stimulates type I interferon response via STING pathway activation in these cell lines at 25-50 μM for 4-25 hours. At 10 μM, Enpp-1-IN-27 exhibits negligible inhibition of five major CYP enzyme subtypes (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) and shows excellent metabolic stability with over 95% microsomal stability in human, mouse, and rat liver microsomes. Additionally, it has a high kinetic solubility of 191 μM and does not significantly inhibit human hERG channels (IC50 > 100 μM).

Enpp-1-IN-27 (Compound 31) administered at a dose of 50 mg/kg via intraperitoneal injection once daily for 15-20 days showed promising antitumor activity in 4T1 and CT26 syngeneic mouse models, without any significant toxicity or adverse effects observed. A single dose of Enpp-1-IN-27 (50 mg/kg, intraperitoneal injection) demonstrated high safety, as key hepatic biomarkers, including aspartate aminotransferase (AST) and alanine aminotransferase (ALT), along with nephrotoxic indicators such as blood urea nitrogen (BUN) and serum creatinine, remained within normal limits.