Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, People's Republic of China.
Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China.
Eur J Drug Metab Pharmacokinet. 2021 Jan;46(1):129-139. doi: 10.1007/s13318-020-00659-9.
Rapamycin and its semi-synthetic analogues (rapalogues) are frequently used in combination with other prescribed medications in clinical settings. Although the inhibitory effects of rapalogues on cytochrome P450 enzymes (CYPs) have been well examined, the inhibition potentials of rapalogues on human esterases have not been investigated. Herein, the inhibition potentials and inhibitory mechanisms of six marketed rapalogues on human esterases are investigated.
The inhibitory effects of six marketed rapalogues (rapamycin, zotarolimus, temsirolimus, everolimus, pimecrolimus and tacrolimus) on three major esterases, including human carboxylesterases 1 (hCES1A), human carboxylesterases 2 (hCES2A) and butyrylcholinesterase (BuChE), were assayed using isozyme-specific substrates. Inhibition kinetic analyses and docking simulations were performed to investigate the inhibitory mechanisms of the rapalogues with strong hCES2A inhibition potency.
Zotarolimus and pimecrolimus displayed strong inhibition of human hCES2A but these agents did not inhibit hCES1A or BuChE. Further investigation demonstrated that zotarolimus could strongly inhibit intracellular hCES2A in living HepG2 cells, with an estimated IC value of 4.09 µM. Inhibition kinetic analyses revealed that zotarolimus inhibited hCES2A-catalyzed fluorescein diacetate hydrolysis in a mixed manner, with the K value of 1.61 µM. Docking simulations showed that zotarolimus could tightly bind on hCES2A at two district ligand-binding sites, consistent with its mixed inhibition mode.
Our findings demonstrate that several marketed rapalogues are potent and specific hCES2A inhibitors, and these agents can serve as leading compounds for the development of more efficacious hCES2A inhibitors to modulate the pharmacokinetic profiles and toxicity of hCES2A-substrate drugs (such as the anticancer agent irinotecan).
雷帕霉素及其半合成类似物（雷帕霉素类似物）经常在临床环境中与其他规定的药物联合使用。尽管雷帕霉素类似物对细胞色素 P450 酶（CYPs）的抑制作用已得到充分研究，但尚未研究雷帕霉素类似物对人酯酶的抑制潜力。在此，研究了六种市售雷帕霉素类似物对人酯酶的抑制潜力和抑制机制。
使用同工酶特异性底物测定了六种市售雷帕霉素类似物（雷帕霉素、佐他莫司、替西罗莫司、依维莫司、吡美莫司和他克莫司）对三种主要酯酶（人羧酸酯酶 1（hCES1A）、人羧酸酯酶 2（hCES2A）和丁酰胆碱酯酶（BuChE））的抑制作用。进行抑制动力学分析和对接模拟，以研究具有强 hCES2A 抑制活性的雷帕霉素类似物的抑制机制。
佐他莫司和吡美莫司对人 hCES2A 显示出强烈的抑制作用，但这些药物不抑制 hCES1A 或 BuChE。进一步的研究表明，佐他莫司可以强烈抑制活 HepG2 细胞内的 hCES2A，估计 IC 值为 4.09 µM。抑制动力学分析表明，佐他莫司以混合方式抑制 hCES2A 催化的荧光素二乙酸酯水解，K 值为 1.61 µM。对接模拟表明，佐他莫司可以紧密结合 hCES2A 的两个区配体结合位点，与其混合抑制模式一致。
我们的研究结果表明，几种市售雷帕霉素类似物是强效和特异性的 hCES2A 抑制剂，这些药物可以作为开发更有效的 hCES2A 抑制剂的先导化合物，以调节 hCES2A 底物药物（如抗癌药伊立替康）的药代动力学特征和毒性。
