Design, synthesis, and biological evaluation studies of novel carboxylesterase 2 inhibitors for the treatment of irinotecan-induced delayed diarrhea

• Published in: Bioorganic chemistry 2023-09, Vol.138, p.106625-106625, Article 106625
• Main Authors: Yang, Zhongcheng, Cao, Zhijun, Wang, Wenxin, Chen, Ya, Huang, Wanqiu, Jiao, Shixuan, Chen, Siliang, Chen, Lianru, Liu, Yuxia, Mao, Jianming, Zhang, Luyong, Li, Zheng
• Format: Article
• Language: English
• Subjects: Delayed diarrhea; Diarrhea - chemically induced; Diarrhea - drug therapy; Enzyme Inhibitors - pharmacology; Enzyme Inhibitors - therapeutic use; Human carboxylesterase 2; Humans; Irinotecan; Irinotecan - adverse effects; Molecular docking; Molecular Docking Simulation; Molecular Dynamics Simulation
• ISSN: 0045-2068; 1090-2120
• DOI: 10.1016/j.bioorg.2023.106625

To alleviate the side effects of delayed diarrhea caused by irinotecan, the lead compound 01 with novel skeleton was obtained by high-throughput screening in our in-house library, which resulting in the discovery of hCES2A inhibitor LK-44. [Display omitted] •LK-44 is a potent inhibitor of hCES2A and exhibits high selectivity against hCES1A.•LK-44 forms multiple interactions with key residues of hCES2A.•This study reveals the key energy-contributing amino acids in the binding pocket.•LK-44 significantly improves the delayed diarrhea induced by irinotecan.•This study provides a promising lead compound to explore better hCES2A inhibitors. Human carboxylesterase 2 (hCES2A), one of the most important serine hydrolases distributed in the small intestine and colon, plays a crucial role in the hydrolysis of various prodrugs and esters. Accumulating evidence has demonstrated that the inhibition of hCES2A effectively alleviate the side effects induced by some hCES2A-substrate drugs, including delayed diarrhea caused by the anticancer drug irinotecan. Nonetheless, there is a scarcity of selective and effective inhibitors that are suitable for irinotecan-induced delayed diarrhea. Following screening of the in-house library, the lead compound 01 was identified with potent inhibition on hCES2A, which was further optimized to obtain LK-44 with potent inhibitory activity (IC50 = 5.02 ± 0.67 μM) and high selectivity on hCES2A. Molecular docking and molecular dynamics simulations indicated that LK-44 can formed stable hydrogen bonds with amino acids surrounding the active cavity of hCES2A. The results of inhibition kinetics studies unveiled that LK-44 inhibited hCES2A-mediated FD hydrolysis in a mixed inhibition manner, with a Ki value of 5.28 μM. Notably, LK-44 exhibited low toxicity towards HepG2 cells according to the MTT assay. Importantly, in vivo studies showed that LK-44 significantly reduced the side effects of irinotecan-induced diarrhea. These findings suggested that LK-44 is a potent inhibitor of hCES2A with high selectivity against hCES1A, which has potential as a lead compound for the development of more effective hCES2A inhibitors to mitigate irinotecan-induced delayed diarrhea.