Synthesis, characterization, molecular docking, and biological evaluation of novel ASK1 inhibitors

Abstract

Apoptosis signal regulated kinase 1 (ASK1, also known as MAP3K5) is a member of the mitogen activated protein kinase (MAPK) signaling pathway that participates in cell survival, differentiation, stress responses, and apoptosis. Inhibiting ASK1 is an attractive strategy for treating diseases such as nonalcoholic steatohepatitis and multiple sclerosis. Here, we explored and synthesized a series of new skeleton compounds containing hydrogenated indole, indole, benzimidazole, tetrahydroquinoxaline, benzoxazine, tetrahydroquinoline, phenol, nitrobenzene, pyridine as ASK1 inhibitors. Among them, 44a and 44b containing 2-triazolylpyridine fragment showed the potent inhibitory activity, with IC50 values of 0.15 and 0.31 μM, respectively. In addition, the cell survival rates of 44a and 44b at different concentrations were greater than 90%, especially at 0.05, 0.1, and 0.8 μM, their cell survival rate is higher than GS-4997, indicating that they exhibit good safety in human normal liver LO2 cells. The results of flow cytometry showed that 44a and 44b significantly blocked the progression of the G1 phase cycle. Oil red O staining experiments showed that at a concentration of 8 μM for 44a, only slightly swollen cytoplasmic fat droplets were seen in LO2 cells, and there was no significant fusion between the fat droplets. In addition, 44a, as a representative molecule, was used to study the interaction modes with ASK1 protein through molecular docking. These studies and findings provide a good choice for the future development of ASK1 inhibitors.