Molecular Insights into Microbial β-Glucuronidase Inhibition to Abrogate CPT-11 Toxicity
Molecular Insights into Microbial β-Glucuronidase Inhibition to Abrogate CPT-11 Toxicity
复制标题
DOI：
10.1124/mol.113.085852
复制
发表时间：
2013-08-01
影响因子：
3.6
通讯作者：
Redinbo, Matthew R.
中科院分区：
文献类型：
--
作者：
Roberts, Adam B.;Wallace, Bret D.;Redinbo, Matthew R.
由共生的肠道微生物群表达的细菌β-葡萄糖醛酸苷酶似乎在药物诱导的胃肠道上皮细胞毒性中发挥重要作用。对于抗癌药物CPT-11(伊立替康)和非甾体抗炎药物双氯芬酸，研究表明，GI腔内细菌β-葡萄糖醛酸苷酶将药物代谢物中的葡萄糖醛酸苷部分清除，可显著损害肠道上皮。此外，小分子抑制剂选择性地破坏细菌β-葡萄糖苷酸酶可以减轻这些副作用，对于CPT-11{7-乙基-10-[4-(1-哌啶基)-1-哌啶基]}，这些副作用可能是剂量限制的。在这里，我们表征了新型微生物β-葡萄糖醛酸酶抑制剂，它们在体外抑制大肠杆菌β-葡萄糖苷酸酶，K-I值在180 NM到2 MU M之间，并在大肠杆菌细胞中干扰该酶，EC50值低至300 NM。所有化合物对大肠杆菌β-葡萄糖醛酸苷酶具有选择性，不抑制纯化的哺乳动物β-葡萄糖苷酸酶，并且它们不影响细菌或哺乳动物细胞的生存。一种与大肠杆菌β-葡萄糖苷酸酶结合的抑制剂的2.8埃分辨率晶体结构表明，它只接触和排序存在于微生物而不是哺乳动物的β-葡萄糖醛酸酶中的一部分“细菌环”。在这组研究中检测到的最有效的化合物被发现可以保护小鼠免受CPT-11引起的腹泻。综上所述，这些数据促进了我们对选择性微生物β-葡萄糖醛酸酶抑制的化学和结构基础的理解，这可能会提高人类的药物疗效和毒性。
Bacterial beta-glucuronidases expressed by the symbiotic intestinal microbiota appear to play important roles in drug-induced epithelial cell toxicity in the gastrointestinal (GI) tract. For the anticancer drug CPT-11 (irinotecan) and the nonsteroidal anti-inflammatory drug diclofenac, it has been shown that removal of the glucuronide moieties from drug metabolites by bacterial beta-glucuronidases in the GI lumen can significantly damage the intestinal epithelium. Furthermore, selective disruption of bacterial beta-glucuronidases by small molecule inhibitors alleviates these side effects, which, for CPT-11 {7-ethyl-10-[4-(1-piperidino)-1-piperidino]}, can be dose limiting. Here we characterize novel microbial beta-glucuronidase inhibitors that inhibit Escherichia coli beta-glucuronidase in vitro with K-i values between 180 nM and 2 mu M, and disrupt the enzyme in E. coli cells, with EC50 values as low as 300 nM. All compounds are selective for E. coli beta-glucuronidase without inhibiting purified mammalian beta-glucuronidase, and they do not impact the survival of either bacterial or mammalian cells. The 2.8 angstrom resolution crystal structure of one inhibitor bound to E. coli beta-glucuronidase demonstrates that it contacts and orders only a portion of the "bacterial loop" present in microbial, but not mammalian, beta-glucuronidases. The most potent compound examined in this group was found to protect mice against CPT-11-induced diarrhea. Taken together, these data advance our understanding of the chemical and structural basis of selective microbial beta-glucuronidase inhibition, which may improve human drug efficacy and toxicity.