Influence of Stereochemistry on the Bioactivation and Glucuronidation of 4-Ipomeanol
| Autor: | John P. Kowalski, Constanze Wiek, Dale Whittington, Aaron M. Teitelbaum, Allan E. Rettie, Oliver T. Parkinson, Helmut Hanenberg, Michele Scian, Matthew G. McDonald, Katharina Roellecke |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Stereochemistry Medizin Glucuronidation Metabolism Transport and Pharmacogenomics 03 medical and health sciences 0302 clinical medicine Glucuronides Microsomes medicine Humans Toxins Biological Pharmacology chemistry.chemical_classification Dose-Response Relationship Drug Chemistry Terpenes Niflumic acid Stereoisomerism Hep G2 Cells Prodrug Suicide gene UGT2B7 030104 developmental biology Enzyme Microsome Molecular Medicine Stereoselectivity 030217 neurology & neurosurgery medicine.drug |
| Zdroj: | The Journal of pharmacology and experimental therapeutics. 368(2) |
| ISSN: | 1521-0103 |
| Popis: | A potential CYP4B1 suicide gene application in engineered T-cell treatment of blood cancers has revived interest in the use of 4-ipomeanol (IPO) in gene-directed enzyme prodrug therapy, in which disposition of the administered compound may be critical. IPO contains one chiral center at the carbon bearing a secondary alcohol group; it was of interest to determine the effect of stereochemistry on 1) CYP4B1-mediated bioactivation and 2) (UGT)-mediated glucuronidation. First, (R)-IPO and (S)-IPO were synthesized and used to assess cytotoxicity in HepG2 cells expressing rabbit CYP4B1 and re-engineered human CYP4B1, where the enantiomers were found to be equipotent. Next, a sensitive UPLC-MS/MS assay was developed to measure the IPO-glucuronide diastereomers and product stereoselectivity in human tissue microsomes. Human liver and kidney microsomes generated (R)- and (S)-IPO-glucuronide diastereomers in ratios of 57:43 and 79:21, respectively. In a panel of 13 recombinantly expressed UGTs, UGT1A9 and UGT2B7 were the major isoforms responsible for IPO glucuronidation. (R)-IPO-glucuronide diastereoselectivity was apparent with each recombinant UGT, except UGT2B15 and UGT2B17, which favored the formation of (S)-IPO-glucuronide. Incubations with IPO and the UGT1A9-specific chemical inhibitor niflumic acid significantly decreased glucuronidation in human kidney, but only marginally in human liver microsomes, consistent with known tissue expression patterns of UGTs. We conclude that IPO glucuronidation in human kidney is mediated by UGT1A9 and UGT2B7. In human liver, it is mediated primarily by UGT2B7 and, to a lesser extent, UGT1A9 and UGT2B15. Overall, the lack of pronounced stereoselectivity for IPO's bioactivation in CYP4B1-transfected HepG2 cells, or for hepatic glucuronidation, suggests the racemate is an appropriate choice for use in suicide gene therapies. |
| Databáze: | OpenAIRE |
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