Download MendeleyMolecular Insights into Microbial beta-Glucuronidase Inhibition to Abrogate CPT-11 Toxicity.
Roberts, A.B., Wallace, B.D., Venkatesh, M.K., Mani, S., Redinbo, M.R.(2013) Mol Pharmacol 84: 208-217
- PubMed: 23690068 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1124/mol.113.085852
- Primary Citation Related Structures:
4JHZ - PubMed Abstract:
Bacterial β-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 β-glucuronidases in the GI lumen can significantly damage the intestinal epithelium. Furthermore, selective disruption of bacterial β-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 β-glucuronidase inhibitors that inhibit Escherichia coli β-glucuronidase in vitro with Ki values between 180 nM and 2 μM, and disrupt the enzyme in E. coli cells, with EC50 values as low as 300 nM. All compounds are selective for E. coli β-glucuronidase without inhibiting purified mammalian β-glucuronidase, and they do not impact the survival of either bacterial or mammalian cells. The 2.8 Å resolution crystal structure of one inhibitor bound to E. coli β-glucuronidase demonstrates that it contacts and orders only a portion of the "bacterial loop" present in microbial, but not mammalian, β-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 β-glucuronidase inhibition, which may improve human drug efficacy and toxicity.
- Departments of Biochemistry, Chemistry and Microbiology, University of North Carolina at Chapel Hill, NC, USA.
Organizational Affiliation:
