Synthesis and biological evaluation of quinoxaline derivatives as ASK1 inhibitors

Inhibiting apoptosis signal regulated kinase 1 (ASK1) is an attractive strategy for treating diseases such as non-alcoholic steatohepatitis and multiple sclerosis. Here, we report the discovery of a dibromo substituted quinoxaline fragment containing <b>26e</b> as an effective small-molecule inhibitor of ASK1, with an IC₅₀ value of 30.17 nM. In addition, the cell survival rate of <b>26e</b> at different concentrations was greater than 80%, especially at 0.4 μM. Its cell survival rate was significantly higher than <b>GS-4997</b>, indicating its good safety in normal human liver LO2 cells. The Oil Red O staining experiment showed that <b>26e</b> decreased the lipid droplets in a dose-dependent manner. Further biochemical analyses revealed that <b>26e</b> could reduce the content of T-CHO, LDL, and TG in FFA-induced LO2 cells, and had the potential to treat non-alcoholic fatty disease. These findings provide a good choice for the future development of ASK1 inhibitors.

抑制凋亡信号调节激酶1（apoptosis signal regulated kinase 1, ASK1）是治疗非酒精性脂肪性肝炎（non-alcoholic steatohepatitis）、多发性硬化（multiple sclerosis）等疾病的颇具吸引力的策略。本研究报道了一种含<b>26e</b>的二溴取代喹喔啉（dibromo substituted quinoxaline）片段类小分子ASK1有效抑制剂，其半数抑制浓度（IC₅₀）为30.17 nM。此外，<b>26e</b>在不同浓度下的细胞存活率均高于80%，尤其在0.4 μM浓度时表现优异；其细胞存活率显著优于<b>GS-4997</b>，表明该化合物在正常人肝LO2细胞中具备良好的安全性。油红O染色（Oil Red O staining）实验结果显示，<b>26e</b>可呈剂量依赖性减少细胞内脂滴（lipid droplets）。进一步生化分析表明，<b>26e</b>能够降低游离脂肪酸（free fatty acid, FFA）诱导的LO2细胞内总胆固醇（total cholesterol, T-CHO）、低密度脂蛋白（low-density lipoprotein, LDL）及甘油三酯（triglyceride, TG）的含量，具备治疗非酒精性脂肪性疾病（non-alcoholic fatty disease）的潜力。上述研究结果为未来ASK1抑制剂的开发提供了优质的候选选择。