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Atypical kinetics of cytochrome P450 enzymes in pharmacology and toxicology. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 95:131-176. [PMID: 35953154 DOI: 10.1016/bs.apha.2022.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atypical kinetics are observed in metabolic reactions catalyzed by cytochrome P450 enzymes (P450). Yet, this phenomenon is regarded as experimental artifacts in some instances despite increasing evidence challenging the assumptions of typical Michaelis-Menten kinetics. As P450 play a major role in the metabolism of a wide range of substrates including drugs and endogenous compounds, it becomes critical to consider the impact of atypical kinetics on the accuracy of estimated kinetic and inhibitory parameters which could affect extrapolation of pharmacological and toxicological implications. The first half of this book chapter will focus on atypical non-Michaelis-Menten kinetics (e.g. substrate inhibition, biphasic and sigmoidal kinetics) as well as proposed underlying mechanisms supported by recent insights in mechanistic enzymology. In particular, substrate inhibition kinetics in P450 as well as concurrent drug inhibition of P450 in the presence of substrate inhibition will be further discussed. Moreover, mounting evidence has revealed that despite the high degree of sequence homology between CYP3A isoforms (i.e. CYP3A4 and CYP3A5), they have the propensities to exhibit vastly different susceptibilities and potencies of mechanism-based inactivation (MBI) with a common drug inhibitor. These experimental observations pertaining to the presence of these atypical isoform- and probe substrate-specific complexities in CYP3A isoforms by several clinically-relevant drugs will therefore be expounded and elaborated upon in the second half of this book chapter.
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Kahma H, Aurinsalo L, Neuvonen M, Katajamäki J, Paludetto MN, Viinamäki J, Launiainen T, Filppula AM, Tornio A, Niemi M, Backman JT. An automated cocktail method for in vitro assessment of direct and time-dependent inhibition of nine major cytochrome P450 enzymes - application to establishing CYP2C8 inhibitor selectivity. Eur J Pharm Sci 2021; 162:105810. [PMID: 33753217 DOI: 10.1016/j.ejps.2021.105810] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/26/2021] [Accepted: 03/16/2021] [Indexed: 12/12/2022]
Abstract
We developed an in vitro high-throughput cocktail assay with nine major drug-metabolizing CYP enzymes, optimized for screening of time-dependent inhibition. The method was applied to determine the selectivity of the time-dependent CYP2C8 inhibitors gemfibrozil 1-O-β-glucuronide and clopidogrel acyl-β-D-glucuronide. In vitro incubations with CYP selective probe substrates and pooled human liver microsomes were conducted in 96-well plates with automated liquid handler techniques and metabolite concentrations were measured with quantitative UHPLC-MS/MS analysis. After determination of inter-substrate interactions and Km values for each reaction, probe substrates were divided into cocktails I (tacrine/CYP1A2, bupropion/CYP2B6, amodiaquine/CYP2C8, tolbutamide/CYP2C9 and midazolam/CYP3A4/5) and II (coumarin/CYP2A6, S-mephenytoin/CYP2C19, dextromethorphan/CYP2D6 and astemizole/CYP2J2). Time-dependent inhibitors (furafylline/CYP1A2, selegiline/CYP2A6, clopidogrel/CYP2B6, gemfibrozil 1-O-β-glucuronide/CYP2C8, tienilic acid/CYP2C9, ticlopidine/CYP2C19, paroxetine/CYP2D6 and ritonavir/CYP3A) and direct inhibitor (terfenadine/CYP2J2) showed similar inhibition with single substrate and cocktail methods. Established time-dependent inhibitors caused IC50 fold shifts ranging from 2.2 to 30 with the cocktail method. Under time-dependent inhibition conditions, gemfibrozil 1-O-β-glucuronide was a strong (>90% inhibition) and selective (<< 20% inhibition of other CYPs) inhibitor of CYP2C8 at concentrations ranging from 60 to 300 μM, while the selectivity of clopidogrel acyl-β-D-glucuronide was limited at concentrations above its IC80 for CYP2C8. The time-dependent IC50 values of these glucuronides for CYP2C8 were 8.1 and 38 µM, respectively. In conclusion, a reliable cocktail method including the nine most important drug-metabolizing CYP enzymes was developed, optimized and validated for detecting time-dependent inhibition. Moreover, gemfibrozil 1-O-β-glucuronide was established as a selective inhibitor of CYP2C8 for use as a diagnostic inhibitor in in vitro studies.
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Affiliation(s)
- Helinä Kahma
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Clinical Pharmacology, HUS Diagnostic Center, Helsinki University Hospital, Helsinki, Finland
| | - Laura Aurinsalo
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mikko Neuvonen
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jani Katajamäki
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Marie-Noëlle Paludetto
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jenni Viinamäki
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland
| | - Terhi Launiainen
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland
| | - Anne M Filppula
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Aleksi Tornio
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Clinical Pharmacology, HUS Diagnostic Center, Helsinki University Hospital, Helsinki, Finland
| | - Mikko Niemi
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Clinical Pharmacology, HUS Diagnostic Center, Helsinki University Hospital, Helsinki, Finland
| | - Janne T Backman
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Clinical Pharmacology, HUS Diagnostic Center, Helsinki University Hospital, Helsinki, Finland.
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Schleiff MA, Flynn NR, Payakachat S, Schleiff BM, Pinson AO, Province DW, Swamidass SJ, Boysen G, Miller GP. Significance of Multiple Bioactivation Pathways for Meclofenamate as Revealed through Modeling and Reaction Kinetics. Drug Metab Dispos 2020; 49:133-141. [PMID: 33239334 PMCID: PMC7841419 DOI: 10.1124/dmd.120.000254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/05/2020] [Indexed: 12/20/2022] Open
Abstract
Meclofenamate is a nonsteroidal anti-inflammatory drug used in the treatment of mild-to-moderate pain yet poses a rare risk of hepatotoxicity through an unknown mechanism. Nonsteroidal anti-inflammatory drug (NSAID) bioactivation is a common molecular initiating event for hepatotoxicity. Thus, we hypothesized a similar mechanism for meclofenamate and leveraged computational and experimental approaches to identify and characterize its bioactivation. Analyses employing our XenoNet model indicated possible pathways to meclofenamate bioactivation into 19 reactive metabolites subsequently trapped into glutathione adducts. We describe the first reported bioactivation kinetics for meclofenamate and relative importance of those pathways using human liver microsomes. The findings validated only four of the many bioactivation pathways predicted by modeling. For experimental studies, dansyl glutathione was a critical trap for reactive quinone metabolites and provided a way to characterize adduct structures by mass spectrometry and quantitate yields during reactions. Of the four quinone adducts, we were able to characterize structures for three of them. Based on kinetics, the most efficient bioactivation pathway led to the monohydroxy para-quinone-imine followed by the dechloro-ortho-quinone-imine. Two very inefficient pathways led to the dihydroxy ortho-quinone and a likely multiply adducted quinone. When taken together, bioactivation pathways for meclofenamate accounted for approximately 13% of total metabolism. In sum, XenoNet facilitated prediction of reactive metabolite structures, whereas quantitative experimental studies provided a tractable approach to validate actual bioactivation pathways for meclofenamate. Our results provide a foundation for assessing reactive metabolite load more accurately for future comparative studies with other NSAIDs and drugs in general.
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Affiliation(s)
- Mary Alexandra Schleiff
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
| | - Noah R Flynn
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
| | - Sasin Payakachat
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
| | - Benjamin Mark Schleiff
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
| | - Anna O Pinson
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
| | - Dennis W Province
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
| | - S Joshua Swamidass
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
| | - Gunnar Boysen
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
| | - Grover P Miller
- Departments of Biochemistry and Molecular Biology (M.A.S, G.P.M.) and Environmental and Occupational Health (G.B.), University of Arkansas for Medical Sciences, Little Rock, Arizona (M.A.S.); Department of Pathology and Immunology, Washington University, St. Louis, Missouri (N.R.F., S.J.S.); Department of Chemistry, Hendrix College, Conway, Arizona (S.P.); and Independent Researcher (B.M.S.) and Department of Chemistry and Biochemistry (A.O.P., D.W.P.), Harding University, Searcy, Arkansas
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In vitro evaluation of the metabolic enzymes and drug interaction potential of triapine. Cancer Chemother Pharmacol 2020; 86:633-640. [PMID: 32989483 DOI: 10.1007/s00280-020-04154-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 09/17/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE To investigate the metabolic pathways of triapine in primary cultures of human hepatocytes and human hepatic subcellular fractions; to investigate interactions of triapine with tenofovir and emtricitabine; and to evaluate triapine as a perpetrator of drug interactions. The results will better inform future clinical studies of triapine, a radiation sensitizer currently being studied in a phase III study. METHODS Triapine was incubated with human hepatocytes and subcellular fractions in the presence of a number of inhibitors of drug metabolizing enzymes. Triapine depletion was monitored by LC-MS/MS. Tenofovir and emtricitabine were co-incubated with triapine in primary cultures of human hepatocytes. Triapine was incubated with a CYP probe cocktail and human liver microsomes, followed by LC-MS/MS monitoring of CYP specific metabolite formation. RESULTS Triapine was not metabolized by FMO, AO/XO, MAO-A/B, or NAT-1/2, but was metabolized by CYP450s. CYP1A2 accounted for most of the depletion of triapine. Tenofovir and emtricitabine did not alter triapine depletion. Triapine reduced CYP1A2 activity and increased CYP2C19 activity. CONCLUSION CYP1A2 metabolism is the major metabolic pathway for triapine. Triapine may be evaluated in cancer patients in the setting of HIV with emtricitabine or tenofovir treatment. Confirmatory clinical trials may further define the in vivo triapine metabolic fate and quantify any drug-drug interactions.
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Danek PJ, Wójcikowski J, Daniel WA. The atypical neuroleptics iloperidone and lurasidone inhibit human cytochrome P450 enzymes in vitro. Evaluation of potential metabolic interactions. Pharmacol Rep 2020; 72:1685-1694. [PMID: 32279279 PMCID: PMC7704495 DOI: 10.1007/s43440-020-00102-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/20/2020] [Accepted: 03/31/2020] [Indexed: 02/07/2023]
Abstract
Background The present study aimed at examining the inhibitory effect of two atypical neuroleptics iloperidone and lurasidone on the main human cytochrome P450 (CYP) enzymes in pooled human liver microsomes and cDNA-expressed CYP enzymes (supersomes). Methods The activity of these enzymes was determined by the following CYP-specific reactions: caffeine 3-N-demethylation/CYP1A2, diclofenac 4′-hydroxylation/CYP2C9, perazine N-demethylation/CYP2C19, bufuralol 1′-hydroxylation/CYP2D6 and testosterone 6β-hydroxylation/CYP3A4, respectively, using HPLC. Results Iloperidone inhibited the activity of CYP3A4 via a noncompetitive mechanism (Ki = 0.38 and 0.3 µM in liver microsomes and supersomes, respectively) and CYP2D6 via a competitive mechanism (Ki = 2.9 and 10 µM in microsomes and supersomes). Moreover, iloperidone attenuated the activity of CYP1A2 (Ki = 45 and 31 µM in microsomes and supersomes) and CYP2C19 via a mixed mechanism (Ki = 6.5 and 32 µM in microsomes and supersomes) but did not affect CYP2C9. Lurasidone moderately inhibited CYP1A2 (Ki = 12.6 and 15.5 µM in microsomes and supersomes), CYP2C9 (Ki = 18 and 3.5 µM in microsomes and supersomes) and CYP2C19 via a mixed mechanism (Ki = 18 and 18.4 µM in microsomes and supersomes), and CYP3A4 via a competitive mechanism (Ki = 29.4 and 9.1 µM in microsomes and supersomes). Moreover, lurasidone competitively, though weakly diminished the CYP2D6 activity (Ki = 37.5 and 85 µM in microsomes and supersomes). Conclusion The examined neuroleptics showed inhibitory effects on different CYP enzymes. The obtained results indicate that metabolic/pharmacokinetic interactions with iloperidone (involving mainly CYP3A4 and CYP2D6) and possibly with lurasidone (involving CYP1A2, CYP2C9 or CYP2C19) may occur during combined therapy.
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Affiliation(s)
- Przemysław J Danek
- Department of Pharmacokinetics and Drug Metabolism, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Jacek Wójcikowski
- Department of Pharmacokinetics and Drug Metabolism, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Władysława A Daniel
- Department of Pharmacokinetics and Drug Metabolism, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
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Kahma H, Filppula AM, Launiainen T, Viinamäki J, Neuvonen M, Evangelista EA, Totah RA, Backman JT. Critical Differences between Enzyme Sources in Sensitivity to Detect Time-Dependent Inactivation of CYP2C8. Drug Metab Dispos 2019; 47:436-443. [PMID: 30709838 PMCID: PMC11022894 DOI: 10.1124/dmd.118.085498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/24/2019] [Indexed: 12/18/2022] Open
Abstract
Clopidogrel acyl-β-d-glucuronide is a mechanism-based inhibitor of cytochrome P450 2C8 in human liver microsomes (HLMs). However, time-dependent inactivation (TDI) of CYP2C8 could not be detected in an earlier study in human recombinant CYP2C8 (Supersomes). Here, we investigate whether different enzyme sources exhibit differences in detection of CYP2C8 TDI under identical experimental conditions. Inactivation of CYP2C8 by amiodarone (100 μM), clopidogrel acyl-β-d-glucuronide (100 μM), gemfibrozil 1-O-β-glucuronide (100 μM), and phenelzine (100 μM) was investigated in HLMs and three recombinant human CYP2C8 preparations (Supersomes, Bactosomes, and EasyCYP Bactosomes) using amodiaquine N-deethylation as the marker reaction. Furthermore, the inactivation kinetics of CYP2C8 by clopidogrel glucuronide (5-250 μM) was determined in Supersomes and Bactosomes. Amiodarone caused weak TDI in all enzyme preparations tested, while the extent of inactivation by clopidogrel glucuronide, gemfibrozil glucuronide, and phenelzine varied markedly between preparations, and even different Supersome lots. Both glucuronides caused strong inactivation of CYP2C8 in HLMs, Bactosomes and in one Supersome lot (>50% inhibition), but significant inactivation could not be reliably detected in other Supersome lots or EasyCYP Bactosomes. In Bactosomes, the concentration producing half of kinact (KI) and maximal inactivation rate (kinact) of clopidogrel glucuronide (14 μM and 0.054 minute-1) were similar to those determined previously in HLMs. Phenelzine caused strong inactivation of CYP2C8 in one Supersome lot (91% inhibition) but not in HLMs or other recombinant CYP2C8 preparations. In conclusion, different enzyme sources and different lots of the same recombinant enzyme preparation are not equally sensitive to detect inactivation of CYP2C8, suggesting that recombinant CYPs should be avoided when identifying mechanism-based inhibitors.
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Affiliation(s)
- Helinä Kahma
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Anne M Filppula
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Terhi Launiainen
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Jenni Viinamäki
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Mikko Neuvonen
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Eric A Evangelista
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Rheem A Totah
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
| | - Janne T Backman
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, and Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland (H.K., A.M.F., T.L., J.V., M.N., J.T.B.) and Department of Medicinal Chemistry, University of Washington, Seattle, Washington (E.A.E., R.A.T.)
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Peters SA, Jones CR, Ungell AL, Hatley OJD. Predicting Drug Extraction in the Human Gut Wall: Assessing Contributions from Drug Metabolizing Enzymes and Transporter Proteins using Preclinical Models. Clin Pharmacokinet 2016; 55:673-96. [PMID: 26895020 PMCID: PMC4875961 DOI: 10.1007/s40262-015-0351-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Intestinal metabolism can limit oral bioavailability of drugs and increase the risk of drug interactions. It is therefore important to be able to predict and quantify it in drug discovery and early development. In recent years, a plethora of models-in vivo, in situ and in vitro-have been discussed in the literature. The primary objective of this review is to summarize the current knowledge in the quantitative prediction of gut-wall metabolism. As well as discussing the successes of current models for intestinal metabolism, the challenges in the establishment of good preclinical models are highlighted, including species differences in the isoforms; regional abundances and activities of drug metabolizing enzymes; the interplay of enzyme-transporter proteins; and lack of knowledge on enzyme abundances and availability of empirical scaling factors. Due to its broad specificity and high abundance in the intestine, CYP3A is the enzyme that is frequently implicated in human gut metabolism and is therefore the major focus of this review. A strategy to assess the impact of gut wall metabolism on oral bioavailability during drug discovery and early development phases is presented. Current gaps in the mechanistic understanding and the prediction of gut metabolism are highlighted, with suggestions on how they can be overcome in the future.
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Affiliation(s)
- Sheila Annie Peters
- Translational Quantitative Pharmacology, BioPharma, R&D Global Early Development, Merck KGaA, Frankfurter Str. 250, F130/005, 64293, Darmstadt, Germany.
| | | | - Anna-Lena Ungell
- Investigative ADME, Non-Clinical Development, UCB New Medicines, BioPharma SPRL, Braine l'Alleud, Belgium
| | - Oliver J D Hatley
- Simcyp Limited (A Certara Company), Blades Enterprise Centre, Sheffield, UK
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Pivotal role of P450-P450 interactions in CYP3A4 allostery: the case of α-naphthoflavone. Biochem J 2013; 453:219-30. [PMID: 23651100 DOI: 10.1042/bj20130398] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We investigated the relationship between oligomerization of CYP3A4 (cytochrome P450 3A4) and its response to ANF (α-naphthoflavone), a prototypical heterotropic activator. The addition of ANF resulted in over a 2-fold increase in the rate of CYP3A4-dependent debenzylation of 7-BFC [7-benzyloxy-4-(trifluoromethyl)coumarin] in HLM (human liver microsomes), but failed to produce activation in BD Supersomes or Baculosomes containing recombinant CYP3A4 and NADPH-CPR (cytochrome P450 reductase). However, incorporation of purified CYP3A4 into Supersomes containing only recombinant CPR reproduced the behaviour observed with HLM. The activation in this system was dependent on the surface density of the enzyme. Although no activation was detectable at an L/P (lipid/P450) ratio ≥750, it reached 225% at an L/P ratio of 140. To explore the relationship between this effect and CYP3A4 oligomerization, we probed P450-P450 interactions with a new technique that employs LRET (luminescence resonance energy transfer). The amplitude of LRET in mixed oligomers of the haem protein labelled with donor and acceptor fluorophores exhibited a sigmoidal dependence on the surface density of CYP3A4 in Supersomes™. The addition of ANF eliminated this sigmoidal character and increased the degree of oligomerization at low enzyme concentrations. Therefore the mechanisms of CYP3A4 allostery with ANF involve effector-dependent modulation of P450-P450 interactions.
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Zhou D, Andersson TB, Grimm SW. In Vitro Evaluation of Potential Drug-Drug Interactions with Ticagrelor: Cytochrome P450 Reaction Phenotyping, Inhibition, Induction, and Differential Kinetics. Drug Metab Dispos 2010; 39:703-10. [DOI: 10.1124/dmd.110.037143] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Denisov IG, Frank DJ, Sligar SG. Cooperative properties of cytochromes P450. Pharmacol Ther 2009; 124:151-67. [PMID: 19555717 DOI: 10.1016/j.pharmthera.2009.05.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 05/28/2009] [Indexed: 02/07/2023]
Abstract
Cytochromes P450 form a large and important class of heme monooxygenases with a broad spectrum of substrates and corresponding functions, from steroid hormone biosynthesis to the metabolism of xenobiotics. Despite decades of study, the molecular mechanisms responsible for the complex non-Michaelis behavior observed with many members of this superfamily during metabolism, often termed 'cooperativity', remain to be fully elucidated. Although there is evidence that oligomerization may play an important role in defining the observed cooperativity, some monomeric cytochromes P450, particularly those involved in xenobiotic metabolism, also display this behavior due to their ability to simultaneously bind several substrate molecules. As a result, formation of distinct enzyme-substrate complexes with different stoichiometry and functional properties can give rise to homotropic and heterotropic cooperative behavior. This review aims to summarize the current understanding of cooperativity in cytochromes P450, with a focus on the nature of cooperative effects in monomeric enzymes.
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Affiliation(s)
- Ilia G Denisov
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, United States of America
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11
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Kapelyukh Y, Paine MJI, Maréchal JD, Sutcliffe MJ, Wolf CR, Roberts GCK. Multiple substrate binding by cytochrome P450 3A4: estimation of the number of bound substrate molecules. Drug Metab Dispos 2008; 36:2136-44. [PMID: 18645035 DOI: 10.1124/dmd.108.021733] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cytochrome P450 3A4, a major drug-metabolizing enzyme in man, is well known to show non-Michaelis-Menten steady-state kinetics for a number of substrates, indicating that more than one substrate can bind to the enzyme simultaneously, but it has proved difficult to obtain reliable estimates of exactly how many substrate molecules can bind. We have used a simple method involving studies of the effect of large inhibitors on the Hill coefficient to provide improved estimates of substrate stoichiometry from simple steady-state kinetics. Using a panel of eight inhibitors, we show that at least four molecules of the widely used CYP3A4 substrate 7-benzyloxyquinoline can bind simultaneously to the enzyme. Computational docking studies show that this is consistent with the recently reported crystal structures of the enzyme. In the case of midazolam, which shows simple Michaelis-Menten kinetics, the inhibitor effects demonstrate that two molecules must bind simultaneously, consistent with earlier evidence, whereas for diltiazem, the experiments provide no evidence for the binding of more than one molecule. The consequences of this "inhibitor-induced cooperativity" for the prediction of pharmacokinetics and drug-drug interactions are discussed.
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Affiliation(s)
- Yury Kapelyukh
- Biomedical Research Centre, University of Dundee, Ninewells Hospital and Medical, School, Dundee, United Kingdom
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12
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13
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Kumar V, Rock DA, Warren CJ, Tracy TS, Wahlstrom JL. Enzyme source effects on CYP2C9 kinetics and inhibition. Drug Metab Dispos 2006; 34:1903-8. [PMID: 16928789 PMCID: PMC2377028 DOI: 10.1124/dmd.106.010249] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
When choosing a recombinant cytochrome P450 (P450) enzyme system for in vitro studies, it is critical to understand the strengths, limitations, and applicability of the enzyme system to the study design. Although literature kinetic data may be available to assist in enzyme system selection, comparison of data from separate laboratories is often confounded by differences in experimental conditions and bioanalytical techniques. We measured the Michaelis-Menten kinetic parameters for four CYP2C9 substrates (diclofenac, (S)-warfarin, tolbutamide, and (S)-flurbiprofen) using four recombinant CYP2C9 enzyme systems (Supersomes, Baculosomes, RECO system, and in-house purified, reconstituted enzyme) to determine whether the enzyme systems exhibited kinetic differences in metabolic product formation rates under uniform experimental conditions. The purified, reconstituted enzyme systems exhibited higher K(m) values, reduced substrate affinity, and lower calculated intrinsic clearance values compared with baculovirus microsomal preparations. Six- to 25-fold differences in predicted intrinsic clearance values were calculated for each substrate depending on the enzyme system-substrate combination. Results suggest that P450 reductase interactions with the CYP2C9 protein and varying ratios of CYP2C9/P450 reductase in the enzyme preparations may play a role in these observed differences. In addition, when (S)-flurbiprofen was used as a substrate probe to determine CYP2C9 inhibition with a set of 12 inhibitors, decreased inhibition potency was observed across 11 of those inhibitors in the RECO purified, reconstituted enzyme compared with the Supersomes baculovirus microsomal preparation and pooled human liver microsomes. Considering these differences, consistent use of an enzyme source is an important component in producing comparable and reproducible kinetics and inhibition data with CYP2C9.
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Affiliation(s)
- Vikas Kumar
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN, USA
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14
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Xu L, Krenitsky DM, Seacat AM, Butenhoff JL, Tephly TR, Anders MW. N-glucuronidation of perfluorooctanesulfonamide by human, rat, dog, and monkey liver microsomes and by expressed rat and human UDP-glucuronosyltransferases. Drug Metab Dispos 2006; 34:1406-10. [PMID: 16720684 DOI: 10.1124/dmd.106.009399] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
N-Alkylperfluorooctanesulfonamides have been used in a range of industrial and commercial applications. Perfluorooctanesulfonamide (FOSA) is a major metabolite of N-alkylperfluorooctanesulfonamides and has a long half-life in animals and in the environment and is biotransformed to FOSA N-glucuronide. The objective of this study was to identify and characterize the human and experimental animal liver UDP-glucuronosyltransferases (UGTs) that catalyze the N-glucuronidation of FOSA. The results showed that pooled human liver and rat liver microsomes had high N-glucuronidation activities. Expressed rat UGT1.1, UGT2B1, and UGT2B12 in HK293 cells catalyzed the N-glucuronidation of FOSA but at rates that were lower than those observed in rat liver microsomes. Of the 10 expressed human UGTs (1A1, 1A3, 1A4, 1A6, 1A9, 2B4, 2B7, 2B15, and 2B17) studied, only hUGT2B4 and hUGT2B7 catalyzed the N-glucuronidation of FOSA. The kinetics of N-glucuronidation of FOSA by rat liver microsomes and by hUGT2B4/7 was consistent with a single-enzyme Michaelis-Menten model, whereas human liver microsomes showed sigmoidal kinetics. These data show that rat liver UGT1.1, UGT2B1, and UGT2B12 catalyze the N-glucuronidation of FOSA, albeit at low rates, and that hUGT2B4 and hUGT2B7 catalyze the N-glucuronidation of FOSA.
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Affiliation(s)
- Lin Xu
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 711, Rochester, NY 14642, USA
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15
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Chen Q, Tan E, Strauss JR, Zhang Z, Fenyk-Melody JE, Booth-Genthe C, Rushmore TH, Stearns RA, Evans DC, Baillie TA, Tang W. Effect of Quinidine on the 10-Hydroxylation ofR-Warfarin: Species Differences and Clearance Projection. J Pharmacol Exp Ther 2004; 311:307-14. [PMID: 15163679 DOI: 10.1124/jpet.104.069955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stimulation by quinidine of warfarin metabolism in vitro was first demonstrated with liver microsomal preparations. We report herein that this drug interaction is reproducible in an animal model but that it exhibits profound species differences. Thus, using rabbit liver microsomes and a kinetic model incorporating two binding sites, the hepatic intrinsic clearance of R-warfarin via the 10-hydroxylation pathway (CL(int)(W)) was projected to be 6 +/- 1 and 128 +/- 51 microl/min/g liver, respectively, in the absence and presence of 21 microM unbound quinidine. These estimates were consistent with the results from studies in which rabbit livers (n = 5) were perfused in situ with R-warfarin or R-warfarin plus quinidine. The CL(int)(W) increased from 7 +/- 3 to 156 +/- 106 microl/min/g liver after increasing the hepatic exposure of unbound quinidine from 0 to 21 microM. In contrast, when liver microsomes or intact livers from rats were examined, R-warfarin metabolism was inhibited by quinidine, the CL(int)(W) decreasing to 26% of the control value after exposure of perfused rat livers (n = 5) to 22 microM unbound quinidine. The third example involved monkey liver microsomes, in which the rate of 10-hydroxylation of R-warfarin was little affected in the presence of quinidine (<2-fold increase). In all three species, the 10-hydroxylation of R-warfarin was catalyzed primarily by members of CYP3A, based on immuno- and chemical inhibition analyses. These findings not only highlight the variability of drug interactions among different species but also suggest that changes in hepatic clearance resulting from stimulation of cytochrome P450 activity may be projected based on estimates generated from corresponding liver microsomal preparations.
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Affiliation(s)
- Qing Chen
- Department of Drug Metabolism, Merck Research Labs., Rahway, NJ 07065, USA
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