1
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André C, Auclair J, Gagné F. The influence of rainfall events on the toxicity of urban wastewaters to freshwater mussels Elliptio complanata. Comp Biochem Physiol C Toxicol Pharmacol 2024; 277:109842. [PMID: 38237842 DOI: 10.1016/j.cbpc.2024.109842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/06/2023] [Accepted: 01/11/2024] [Indexed: 01/21/2024]
Abstract
The cumulative impacts of rainfall frequency and intensity towards the ecotoxicity of urban pollution is gaining more and more attention in these times of climate change. The purpose of this study was to examine the ecotoxicological impacts of combined sewers overflows and municipal effluent discharge sites during 3 periods (years) of varying intensity precipitations to freshwater mussels Elliptio complanata. Mussels were placed in benthic cages for 3 months during the summer at 2 overflow discharge and 8 km downstream sites including an upstream site for three consecutive years with low (164 mm), medium (182 mm) and high (248 mm) amounts of rain. The results revealed that the effects were mainly influenced by suspended matter loadings and to the dissolved components to a lesser extent. Impacts at the downstream and overflow sites were noticeable at the reproduction (vitellogenin), genotoxicity, neurotoxicity (dopamine and serotonin changes) levels in addition to xenobiotic biotransformation revealed by glutathione S-transferase activity and metallothioneins for organic and heavy metals respectively. The site downstream the effluent produced most of the effects compared to the overflow sites in the Saint-Lawrence River. However, the impacts of combined sewers overflows could become problematic in low dilution systems such as small river and lakes.
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Affiliation(s)
- C André
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill, Montréal, Québec H2Y 2E7, Canada
| | - J Auclair
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill, Montréal, Québec H2Y 2E7, Canada
| | - F Gagné
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, 105 McGill, Montréal, Québec H2Y 2E7, Canada..
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2
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Gillam EMJ, Kramlinger VM. Opportunities for Accelerating Drug Discovery and Development by Using Engineered Drug-Metabolizing Enzymes. Drug Metab Dispos 2023; 51:392-402. [PMID: 36460479 DOI: 10.1124/dmd.121.000743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/08/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
The study of drug metabolism is fundamental to drug discovery and development (DDD) since by mediating the clearance of most drugs, metabolic enzymes influence their bioavailability and duration of action. Biotransformation can also produce pharmacologically active or toxic products, which complicates the evaluation of the therapeutic benefit versus liability of potential drugs but also provides opportunities to explore the chemical space around a lead. The structures and relative abundance of metabolites are determined by the substrate and reaction specificity of biotransformation enzymes and their catalytic efficiency. Preclinical drug biotransformation studies are done to quantify in vitro intrinsic clearance to estimate likely in vivo pharmacokinetic parameters, to predict an appropriate dose, and to anticipate interindividual variability in response, including from drug-drug interactions. Such studies need to be done rapidly and cheaply, but native enzymes, especially in microsomes or hepatocytes, do not always produce the full complement of metabolites seen in extrahepatic tissues or preclinical test species. Furthermore, yields of metabolites are usually limiting. Engineered recombinant enzymes can make DDD more comprehensive and systematic. Additionally, as renewable, sustainable, and scalable resources, they can also be used for elegant chemoenzymatic, synthetic approaches to optimize or synthesize candidates as well as metabolites. Here, we will explore how these new tools can be used to enhance the speed and efficiency of DDD pipelines and provide a perspective on what will be possible in the future. The focus will be on cytochrome P450 enzymes to illustrate paradigms that can be extended in due course to other drug-metabolizing enzymes. SIGNIFICANCE STATEMENT: Protein engineering can generate enhanced versions of drug-metabolizing enzymes that are more stable, better suited to industrial conditions, and have altered catalytic activities, including catalyzing non-natural reactions on structurally complex lead candidates. When applied to drugs in development, libraries of engineered cytochrome P450 enzymes can accelerate the identification of active or toxic metabolites, help elucidate structure activity relationships, and, when combined with other synthetic approaches, provide access to novel structures by regio- and stereoselective functionalization of lead compounds.
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Affiliation(s)
- Elizabeth M J Gillam
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, Australia (E.M.J.G.) and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee (V.M.K.)
| | - Valerie M Kramlinger
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, Australia (E.M.J.G.) and Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee (V.M.K.)
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3
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Citalopram and Cannabidiol: In Vitro and In Vivo Evidence of Pharmacokinetic Interactions Relevant to the Treatment of Anxiety Disorders in Young People. J Clin Psychopharmacol 2021; 41:525-533. [PMID: 34121064 DOI: 10.1097/jcp.0000000000001427] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Cannabidiol (CBD), a major nonintoxicating constituent of cannabis, exhibits anxiolytic properties in preclinical and human studies and is of interest as a novel intervention for treating anxiety disorders. Existing first-line pharmacotherapies for these disorders include selective serotonin reuptake inhibitor and other antidepressants. Cannabidiol has well-described inhibitory action on cytochrome P450 (CYP450) drug-metabolizing enzymes and significant drug-drug interactions (DDIs) between CBD and various anticonvulsant medications (eg, clobazam) have been described in the treatment of epilepsy. Here, we examined the likelihood of DDIs when CBD is added to medications prescribed in the treatment of anxiety. METHODS The effect of CBD on CYP450-mediated metabolism of the commonly used antidepressants fluoxetine, sertraline, citalopram, and mirtazapine were examined in vitro. Cannabidiol-citalopram interactions were also examined in vivo in patients (n = 6) with anxiety disorders on stable treatment with citalopram or escitalopram who received ascending daily doses of adjunctive CBD (200-800 mg) over 12 weeks in a recent clinical trial. RESULTS Cannabidiol minimally affected the metabolism of sertraline, fluoxetine, and mirtazapine in vitro. However, CBD significantly inhibited CYP3A4 and CYP2C19-mediated metabolism of citalopram and its stereoisomer escitalopram at physiologically relevant concentrations, suggesting a possible in vivo DDI. In patients on citalopram or escitalopram, the addition of CBD significantly increased citalopram plasma concentrations, although it was uncertain whether this also increased selective serotonin reuptake inhibitor-mediated adverse events. CONCLUSIONS Further pharmacokinetic examination of the interaction between CBD and citalopram/escitalopram is clearly warranted, and clinicians should be vigilant around the possibility of treatment-emergent adverse effects when CBD is introduced to patients taking these antidepressants.
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Lim SYM, Alshagga MA, Alshawsh MA, Ong CE, Pan Y. In vitro effects of 95% khat ethanol extract (KEE) on human recombinant cytochrome P450 (CYP)1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2 and CYP3A5. Drug Metab Pers Ther 2021; 37:55-67. [PMID: 35146975 DOI: 10.1515/dmpt-2021-1000196] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 06/21/2021] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Khat, a natural amphetamine-like psychostimulant plant, are widely consumed globally. Concurrent intake of khat and xenobiotics may lead to herb-drug interactions and adverse drug reactions (ADRs). This study is a continuation of our previous study, targeted to evaluate the in vitro inhibitory effects of khat ethanol extract (KEE) on human cytochrome (CYP) 1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2, and CYP3A5, major human drug metabolizing enzymes. METHODS In vitro fluorescence enzyme assays were employed to assess CYPs inhibition with the presence and absence of various KEE concentrations. RESULTS KEE reversibly inhibited CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2 and CYP3A5 but not CYP1A2 with IC50 values of 25.5, 99, 4.5, 21, 27, 17, and 10 μg/mL respectively. No irreversible inhibition of KEE on all the eight CYPs were identified. The Ki values of CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2 and CYP3A5 were 20.9, 85, 4.8, 18.3, 59.3, 3, and 21.7 μg/mL, respectively. KEE inhibited CYP2B6 via competitive or mixed inhibition; CYP2E1 via un-competitive or mixed inhibition; while CYP2A6, CYP2C8, CYP2C19, CYP2J2 and CYP3A5 via non-competitive or mixed inhibition. CONCLUSIONS Caution should be taken by khat users who are on medications metabolized by CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2, and CYP3A5.
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Affiliation(s)
- Sharoen Yu Ming Lim
- Division of Biomedical Science, School of Pharmacy, University of Nottingham Malaysia Campus, Semenyih, Selangor Darul Ehsan, Malaysia
| | - Mustafa Ahmed Alshagga
- Division of Biomedical Science, School of Pharmacy, University of Nottingham Malaysia Campus, Semenyih, Selangor Darul Ehsan, Malaysia
| | | | - Chin Eng Ong
- School of Pharmacy, International Medical University, Wilayah Persekutuan, Kuala Lumpur, Malaysia
| | - Yan Pan
- Division of Biomedical Science, School of Pharmacy, University of Nottingham Malaysia Campus, Semenyih, Selangor Darul Ehsan, Malaysia
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5
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Juvonen RO, Ahinko M, Jokinen EM, Huuskonen J, Raunio H, Pentikäinen OT. Substrate Selectivity of Coumarin Derivatives by Human CYP1 Enzymes: In Vitro Enzyme Kinetics and In Silico Modeling. ACS OMEGA 2021; 6:11286-11296. [PMID: 34056284 PMCID: PMC8153946 DOI: 10.1021/acsomega.1c00123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/08/2021] [Indexed: 05/05/2023]
Abstract
Of the three enzymes in the human cytochrome P450 family 1, CYP1A2 is an important enzyme mediating metabolism of xenobiotics including drugs in the liver, while CYP1A1 and CYP1B1 are expressed in extrahepatic tissues. Currently used CYP substrates, such as 7-ethoxycoumarin and 7-ethoxyresorufin, are oxidized by all individual CYP1 forms. The main aim of this study was to find profluorescent coumarin substrates that are more selective for the individual CYP1 forms. Eleven 3-phenylcoumarin derivatives were synthetized, their enzyme kinetic parameters were determined, and their interactions in the active sites of CYP1 enzymes were analyzed by docking and molecular dynamic simulations. All coumarin derivatives and 7-ethoxyresorufin and 7-pentoxyresorufin were oxidized by at least one CYP1 enzyme. 3-(3-Methoxyphenyl)-6-methoxycoumarin (19) was 7-O-demethylated by similar high efficiency [21-30 ML/(min·mol CYP)] by all CYP1 forms and displayed similar binding in the enzyme active sites. 3-(3-Fluoro-4-acetoxyphenyl)coumarin (14) was selectively 7-O-demethylated by CYP1A1, but with low efficiency [0.16 ML/(min mol)]. This was explained by better orientation and stronger H-bond interactions in the active site of CYP1A1 than that of CYP1A2 and CYP1B1. 3-(4-Acetoxyphenyl)-6-chlorocoumarin (20) was 7-O-demethylated most efficiently by CYP1B1 [53 ML/(min·mol CYP)], followed by CYP1A1 [16 ML/(min·mol CYP)] and CYP1A2 [0.6 ML/(min·mol CYP)]. Variations in stabilities of complexes between 20 and the individual CYP enzymes explained these differences. Compounds 14, 19, and 20 are candidates to replace traditional substrates in measuring activity of human CYP1 enzymes.
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Affiliation(s)
- Risto O. Juvonen
- School
of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Box 1627, 70211 Kuopio, Finland
| | - Mira Ahinko
- Department
of Biological and Environmental Science & Nanoscience Center, University of Jyvaskyla, P.O. Box 35, FI-40014 Jyvaskyla, Finland
| | - Elmeri M. Jokinen
- Institute
of Biomedicine, Faculty of Medicine, Integrative Physiology and Pharmacology, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
| | - Juhani Huuskonen
- Department
of Chemistry, University of Jyvaskyla, P.O. Box 35, FI-40014 Jyvaskyla, Finland
| | - Hannu Raunio
- School
of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Box 1627, 70211 Kuopio, Finland
| | - Olli T. Pentikäinen
- Department
of Biological and Environmental Science & Nanoscience Center, University of Jyvaskyla, P.O. Box 35, FI-40014 Jyvaskyla, Finland
- Institute
of Biomedicine, Faculty of Medicine, Integrative Physiology and Pharmacology, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
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6
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Raunio H, Pentikäinen O, Juvonen RO. Coumarin-Based Profluorescent and Fluorescent Substrates for Determining Xenobiotic-Metabolizing Enzyme Activities In Vitro. Int J Mol Sci 2020; 21:ijms21134708. [PMID: 32630278 PMCID: PMC7369699 DOI: 10.3390/ijms21134708] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 01/03/2023] Open
Abstract
Activities of xenobiotic-metabolizing enzymes have been measured with various in vitro and in vivo methods, such as spectrophotometric, fluorometric, mass spectrometric, and radioactivity-based techniques. In fluorescence-based assays, the reaction produces a fluorescent product from a nonfluorescent substrate or vice versa. Fluorescence-based enzyme assays are usually highly sensitive and specific, allowing measurements on small specimens of tissues with low enzyme activities. Fluorescence assays are also amenable to miniaturization of the reaction mixtures and can thus be done in high throughput. 7-Hydroxycoumarin and its derivatives are widely used as fluorophores due to their desirable photophysical properties. They possess a large π-π conjugated system with electron-rich and charge transfer properties. This conjugated structure leads to applications of 7-hydroxycoumarins as fluorescent sensors for biological activities. We describe in this review historical highlights and current use of coumarins and their derivatives in evaluating activities of the major types of xenobiotic-metabolizing enzyme systems. Traditionally, coumarin substrates have been used to measure oxidative activities of cytochrome P450 (CYP) enzymes. For this purpose, profluorescent coumarins are very sensitive, but generally lack selectivity for individual CYP forms. With the aid of molecular modeling, we have recently described several new coumarin-based substrates for measuring activities of CYP and conjugating enzymes with improved selectivity.
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Affiliation(s)
- Hannu Raunio
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70600 Kuopio, Finland;
- Correspondence:
| | - Olli Pentikäinen
- Institute of Biomedicine, Faculty of Medicine, University of Turku, 20520 Turku, Finland;
| | - Risto O. Juvonen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70600 Kuopio, Finland;
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7
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Mukherjee P, Berns EJ, Patino CA, Hakim Moully E, Chang L, Nathamgari SSP, Kessler JA, Mrksich M, Espinosa HD. Temporal Sampling of Enzymes from Live Cells by Localized Electroporation and Quantification of Activity by SAMDI Mass Spectrometry. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2000584. [PMID: 32452612 PMCID: PMC7401324 DOI: 10.1002/smll.202000584] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/07/2020] [Accepted: 04/16/2020] [Indexed: 05/07/2023]
Abstract
Measuring changes in enzymatic activity over time from small numbers of cells remains a significant technical challenge. In this work, a method for sampling the cytoplasm of cells is introduced to extract enzymes and measure their activity at multiple time points. A microfluidic device, termed the live cell analysis device (LCAD), is designed, where cells are cultured in microwell arrays fabricated on polymer membranes containing nanochannels. Localized electroporation of the cells opens transient pores in the cell membrane at the interface with the nanochannels, enabling extraction of enzymes into nanoliter-volume chambers. In the extraction chambers, the enzymes modify immobilized substrates, and their activity is quantified by self-assembled monolayers for matrix-assisted laser desorption/ionization (SAMDI) mass spectrometry. By employing the LCAD-SAMDI platform, protein delivery into cells is demonstrated. Next, it is shown that enzymes can be extracted, and their activity measured without a loss in viability. Lastly, cells are sampled at multiple time points to study changes in phosphatase activity in response to oxidation by hydrogen peroxide. With this unique sampling device and label-free assay format, the LCAD with SAMDI enables a powerful new method for monitoring the dynamics of cellular activity from small populations of cells.
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Affiliation(s)
- Prithvijit Mukherjee
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA
| | - Eric J Berns
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Cesar A Patino
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | | | - Lingqian Chang
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - S Shiva P Nathamgari
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA
| | - John A Kessler
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Milan Mrksich
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Department of Chemistry, Northwestern University, Evanston, IL, 60208, USA
- Department of Cell and Development Biology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Horacio D Espinosa
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA
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8
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Sasikumar PG, Ramachandra RK, Adurthi S, Dhudashiya AA, Vadlamani S, Vemula K, Vunnum S, Satyam LK, Samiulla DS, Subbarao K, Nair R, Shrimali R, Gowda N, Ramachandra M. A Rationally Designed Peptide Antagonist of the PD-1 Signaling Pathway as an Immunomodulatory Agent for Cancer Therapy. Mol Cancer Ther 2019; 18:1081-1091. [PMID: 31015307 DOI: 10.1158/1535-7163.mct-18-0737] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 10/26/2018] [Accepted: 04/15/2019] [Indexed: 11/16/2022]
Abstract
Pioneering success of antibodies targeting immune checkpoints such as PD-1 and CTLA4 has opened novel avenues for cancer immunotherapy. Along with impressive clinical activity, severe immune-related adverse events (irAE) due to the breaking of immune self-tolerance are becoming increasingly evident in antibody-based approaches. As a strategy to better manage severe adverse effects, we set out to discover an antagonist targeting PD-1 signaling pathway with a shorter pharmacokinetic profile. Herein, we describe a peptide antagonist NP-12 that displays equipotent antagonism toward PD-L1 and PD-L2 in rescue of lymphocyte proliferation and effector functions. In preclinical models of melanoma, colon cancer, and kidney cancers, NP-12 showed significant efficacy comparable with commercially available PD-1-targeting antibodies in inhibiting primary tumor growth and metastasis. Interestingly, antitumor activity of NP-12 in a preestablished CT26 model correlated well with pharmacodynamic effects as indicated by intratumoral recruitment of CD4 and CD8 T cells, and a reduction in PD-1+ T cells (both CD4 and CD8) in tumor and blood. In addition, NP-12 also showed additive antitumor activity in preestablished tumor models when combined with tumor vaccination or a chemotherapeutic agent such as cyclophosphamide known to induce "immunologic cell death." In summary, NP-12 is the first rationally designed peptide therapeutic targeting PD-1 signaling pathways exhibiting immune activation, excellent antitumor activity, and potential for better management of irAEs.
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Affiliation(s)
| | | | - Srinivas Adurthi
- Aurigene Discovery Technologies Limited, Bangalore, Karnataka, India
| | - Amit A Dhudashiya
- Aurigene Discovery Technologies Limited, Bangalore, Karnataka, India
| | | | | | | | - Leena K Satyam
- Aurigene Discovery Technologies Limited, Bangalore, Karnataka, India
| | | | | | - Rashmi Nair
- Aurigene Discovery Technologies Limited, Bangalore, Karnataka, India
| | - Rajeev Shrimali
- Aurigene Discovery Technologies Limited, Bangalore, Karnataka, India
| | - Nagaraj Gowda
- Aurigene Discovery Technologies Limited, Bangalore, Karnataka, India
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9
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Juvonen RO, Ahinko M, Huuskonen J, Raunio H, Pentikäinen OT. Development of new Coumarin-based profluorescent substrates for human cytochrome P450 enzymes. Xenobiotica 2018; 49:1015-1024. [DOI: 10.1080/00498254.2018.1530399] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Risto O. Juvonen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Mira Ahinko
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Juhani Huuskonen
- Department of Chemistry, University of Jyvaskyla, Jyvaskyla, Finland
| | - Hannu Raunio
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Olli T. Pentikäinen
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
- Institute of Biomedicine, Faculty of Medicine Integrative Physiology and Pharmacology, University of Turku, Turku, Finland
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10
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Kosaka M, Kosugi Y, Hirabayashi H. Risk Assessment Using Cytochrome P450 Time-Dependent Inhibition Assays at Single Time and Concentration in the Early Stage of Drug Discovery. J Pharm Sci 2017; 106:2839-2846. [DOI: 10.1016/j.xphs.2017.04.077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/28/2017] [Accepted: 04/28/2017] [Indexed: 02/07/2023]
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11
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Anderson LL, Berns EJ, Bugga P, George AL, Mrksich M. Measuring Drug Metabolism Kinetics and Drug-Drug Interactions Using Self-Assembled Monolayers for Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry. Anal Chem 2016; 88:8604-9. [PMID: 27467208 DOI: 10.1021/acs.analchem.6b01750] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The competition of two drugs for the same metabolizing enzyme is a common mechanism for drug-drug interactions that can lead to altered kinetics in drug metabolism and altered elimination rates in vivo. With the prevalence of multidrug therapy, there is great potential for serious drug-drug interactions and adverse drug reactions. In an effort to prevent adverse drug reactions, the FDA mandates the evaluation of the potential for metabolic inhibition by every new chemical entity. Conventional methods for assaying drug metabolism (e.g., those based on HPLC) have been established for measuring drug-drug interactions; however, they are low-throughput. Here we describe an approach to measure the catalytic activity of CYP2C9 using the high-throughput technique self-assembled monolayers for matrix-assisted laser desorption-ionization (SAMDI) mass spectrometry. We measured the kinetics of CYP450 metabolism of the substrate, screened a set of drugs for inhibition of CYP2C9 and determined the Ki values for inhibitors. The throughput of this platform may enable drug metabolism and drug-drug interactions to be interrogated at a scale that cannot be achieved with current methods.
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Affiliation(s)
- Lyndsey L Anderson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine , Chicago, Illinois 60611, United States
| | | | | | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine , Chicago, Illinois 60611, United States
| | - Milan Mrksich
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine , Chicago, Illinois 60611, United States
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12
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Effect of [Cu(4,7-dimethyl-1,10-phenanthroline)(acetylacetonato)]NO3, Casiopeína III-Ea, on the activity of cytochrome P450. Toxicol In Vitro 2016; 33:16-22. [DOI: 10.1016/j.tiv.2016.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/27/2016] [Accepted: 02/15/2016] [Indexed: 11/19/2022]
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13
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Saad M, Cavanaugh K, Verbueken E, Pype C, Casteleyn C, Van Ginneken C, Van Cruchten S. Xenobiotic metabolism in the zebrafish: a review of the spatiotemporal distribution, modulation and activity of Cytochrome P450 families 1 to 3. J Toxicol Sci 2016; 41:1-11. [DOI: 10.2131/jts.41.1] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Moayad Saad
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Kate Cavanaugh
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Evy Verbueken
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Casper Pype
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Christophe Casteleyn
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Chris Van Ginneken
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
| | - Steven Van Cruchten
- Applied Veterinary Morphology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Belgium
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14
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Sang Z, Long H, Yang T, Ye W, Yang X, Chen G, Wang Z, Luo Y. The in vivo and in vitro phase I metabolism of FYL-67, a novel oxazolidinone antibacterial drug, studied by LC-MS/MS. Drug Test Anal 2015; 8:976-84. [PMID: 26472252 DOI: 10.1002/dta.1887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 08/17/2015] [Accepted: 08/24/2015] [Indexed: 02/05/2023]
Abstract
In our previous study, FYL-67, a novel linezolid analogue with the morpholinyl ring replaced by a 4-(pyridin-2-yl)-1H-pyrazol-1-yl group, was demonstrated to own an excellent activity against Gram-positive organisms,such as methicillin-resistant Staphylococcus aureus (MRSA). However, metabolic biotransformation was not investigated. This study was performed to identify the phase I metabolites of FYL-67 using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The chemical structures were confirmed by comparison with corresponding chemical standards obtained internal. Primary elucidation of the metabolic pathway of FYL-67 in vitro was performed using liver preparations (microsomes and hepatocytes) from rats and humans, and SD (Sprague Dawley, rat, rattus norvegicus) rats were used for the study of in vivo approach. To the end, two metabolites (M1 and M2 ) were detected after in vitro as well as in vivo experiments. Based on LC-MS/MS analyses, the metabolites were demonstrated to be 5-(aminomethyl)-3-(3-fluoro-4-(4-(pyridin-2-yl)-1H-pyrazol-1-yl)phenyl)oxazolidin-2-one (M1 ) and 3-(3-fluoro-4-(4-(pyridin-2-yl)-1H-pyrazol-1-yl)phenyl)-5-(hydroxymethyl)oxazolidin-2-one (M2 ). Amide hydrolysis at acetyl group of FYL-67 leading to the formation of M1 was observed and suggested to play a major role in both in vivo and in vitro phase I metabolism of FYL-67. M1 was demonstrated to undergo a further oxidation to form M2 . In addition, the results indicated no species difference existing between rats and humans. The outcomes of our research can be utilized for the development and validation of the analytical method for the quantification of FYL-67 as well as its metabolites in biological samples. Furthermore, it is helpful to conduct studies of pharmacodynamics and toxicodynamics. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Zitai Sang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital Sichuan University, and Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, 610041, P. R. China
| | - Haiyue Long
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital Sichuan University, and Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, 610041, P. R. China
| | - Tao Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital Sichuan University, and Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, 610041, P. R. China
| | - Weiwei Ye
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital Sichuan University, and Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, 610041, P. R. China
| | - Xiaoyan Yang
- Department of Pharmaceutical and Bioengineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan, 610065, P. R. China
| | - Gong Chen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital Sichuan University, and Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, 610041, P. R. China
| | - Zhenling Wang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital Sichuan University, and Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, 610041, P. R. China
| | - Youfu Luo
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital Sichuan University, and Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, 610041, P. R. China
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15
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Stuchlíková L, Matoušková P, Bártíková H, Vokřál I, Lamka J, Štolcová T, Pětníková H, Szotáková B, Kubíček V, Skálová L. Monepantel induces hepatic cytochromes p450 in sheep in vitro and in vivo. Chem Biol Interact 2015; 227:63-8. [DOI: 10.1016/j.cbi.2014.12.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 12/04/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
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16
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Auw L, Subehan, Sukrasno, Kadota S, Tezuka Y. Constituents of Indonesian Medicinal Plant Averrhoa bilimbi and Their Cytochrome P450 3A4 and 2D6 Inhibitory Activities. Nat Prod Commun 2015. [DOI: 10.1177/1934578x1501000116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
As constituents of Averrhoa bilimbi leaves we identified three new compounds (1-3) together with 12 known ones (4-15); their inhibitory activities on cytochrome P450 3A4 (CYP3A4) and 2D6 (CYP2D6) were examined. Among the isolated compounds, the mixture of 1 and 2, and compounds 4 and 9 showed strong inhibition on CYP3A4, but mild or no inhibition on CYP2D6. These compounds revealed the characteristics of 1) time- and concentration-dependent inhibition, 2) requirement of NADPH for the inhibition, 3) no protection by nucleophiles, and 4) suppression of the inhibition by competitive inhibitor. Thus, they are suggested to be mechanism-based inactivators of CYP3A4 and CYP2D6. The kinetic parameters for the inactivation (kinact and KI) were 0.19 min–1 and 36.7 μM for the mixture of 1 and 2, 0.126 min–1 and 10.5 μM for 4, and 0.29 min–1 and 23.4 μM for 9.
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Affiliation(s)
- Lidyawati Auw
- Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Subehan
- Biofarmaka Research Center, Faculty of Pharmacy, Hasanuddin University, Jl. Perintis Kemerdekaan Km 10, Makassar, 90245, Indonesia
| | - Sukrasno
- School of Pharmacy, Institut Teknologi Bandung, Labtek VII, Ganesha 10, Bandung 40132, Indonesia
| | - Shigetoshi Kadota
- Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Yasuhiro Tezuka
- Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa 920-1181, Japan
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17
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Rundfeldt C, Gasparic A, Wlaź P. Imepitoin as novel treatment option for canine idiopathic epilepsy: pharmacokinetics, distribution, and metabolism in dogs. J Vet Pharmacol Ther 2014; 37:421-34. [PMID: 24611573 PMCID: PMC4280904 DOI: 10.1111/jvp.12117] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 01/21/2014] [Indexed: 11/26/2022]
Abstract
Imepitoin is a novel anti-epileptic licensed in the European Union for the treatment of canine idiopathic epilepsy. The aim of this study was to characterize the pharmacokinetics of imepitoin in dogs and to evaluate the interaction with drug metabolizing enzymes. Upon administration of imepitoin tablets at a dose of 30 mg/kg to beagle dogs, high plasma levels were observed within 30 min following oral dosing, with maximal plasma concentrations of 14.9–17.2 μg/mL reached after 2–3 h. In a crossover study, co-administration of imepitoin tablets with food reduced the total AUC by 30%, but it did not result in significant changes in Tmax and Cmax, indicating lack of clinical relevance. No clinically relevant effects of sex and no accumulation or metabolic tolerance were observed upon twice daily dosing. Following single dose administration of 10–100 mg/kg, dose linearity was found. Administering [14C] imepitoin, high enteral absorption of 92% and primary fecal excretion were identified. Plasma protein binding was only 55%. At therapeutic plasma concentrations, imepitoin did not inhibit microsomal cytochrome P450 family liver enzymes in vitro. In rats, no relevant induction of liver enzymes was found. Therefore, protein binding or metabolism-derived drug–drug interactions are unlikely. Based on these data, imepitoin can be dosed twice daily, but the timing of tablet administration in relation to feeding should be kept consistent.
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18
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Hu HH, Bian YC, Liu Y, Sheng R, Jiang HD, Yu LS, Hu YZ, Zeng S. Evaluation of blood–brain barrier and blood–cerebrospinal fluid barrier permeability of 2-phenoxy-indan-1-one derivatives using in vitro cell models. Int J Pharm 2014; 460:101-7. [DOI: 10.1016/j.ijpharm.2013.11.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 10/29/2013] [Accepted: 11/08/2013] [Indexed: 01/13/2023]
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19
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Murata A, Harada Y, Fukuzumi T, Nakatani K. Fluorescent indicator displacement assay of ligands targeting 10 microRNA precursors. Bioorg Med Chem 2013; 21:7101-6. [PMID: 24084297 DOI: 10.1016/j.bmc.2013.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/04/2013] [Accepted: 09/04/2013] [Indexed: 11/15/2022]
Abstract
Fluorescent indicator displacement (FID) assay is a rapid and convenient assay for identifying new ligands that bind to the target molecules. In our previous studies, we have shown that a series of 2,7-diaminoalkoxy xanthone and thioxanthone derivatives can be used as fluorescent indicators for detecting the interaction between RNA and a ligand. The xanthone and thioxanthone fluorochromes showed efficient fluorescence quenching upon binding to target RNA. Subsequent displacement of the bound-fluorochrome with a ligand that binds more strongly to the target RNA led to the recovery of the fluorescence by releasing the fluorochrome from RNA. Here we report a pilot screening of a chemical library that contains 9600 structurally diverse compounds for molecules that bind to a specific miRNA precursor using the FID assay.
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Affiliation(s)
- Asako Murata
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan
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20
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Bourdon F, Lecoeur M, Verones V, Vaccher C, Lebegue N, Dine T, Kambia N, Goossens JF. In vitro pharmacokinetic profile of a benzopyridooxathiazepine derivative using rat microsomes and hepatocytes: identification of phases I and II metabolites. J Pharm Biomed Anal 2013; 80:69-78. [PMID: 23528331 DOI: 10.1016/j.jpba.2013.02.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 02/12/2013] [Accepted: 02/14/2013] [Indexed: 10/27/2022]
Abstract
In the present study, the in vitro metabolic behavior of a benzopyridooxathiazepine (BZN), a potent tubulin polymerization inhibitor, was investigated by liquid chromatography-UV detection (LC-UV). First, simple and fast LC-UV methods have been optimized and validated to evaluate the pharmacokinetic profile of BZN using rat liver microsomes or hepatocytes primary cultures suspensions. Whatever the medium investigated, baseline resolution between the internal standard and BZN was achieved in a run time less than 15min using a Symmetry ODS column (150mm×4.6mm i.d., 5μm) and a mobile phase consisting of acetonitrile/water/formic acid 60:40:0.1 (v/v/v). Linearity was assessed in the 0.1-50μM and in the 0.05-5μM concentration ranges, respectively, in microsomal and hepatocyte matrix. According to the novel strategy based on the build of the accuracy profile, total error of the developed methods was included within the ±10% limits of acceptance. Then, from incubation of BZN with both liver microsomes and or hepatocytes, structural informations on phase I and phase II metabolites were acquired using liquid chromatography coupled to electrospray orbitrap mass spectrometer (LC-MS). Mass spectrum, double bond equivalent and elemental composition were useful data to access to the chemical structure of each metabolite. In microsomal suspension, four main metabolites were observed including monohydroxylation and dihydroxylation of the benzopyridooxathiazepine core, demethylation of the methoxyphenyl moiety, as well as their combinations. The phase II metabolites detected in hepatocytes suspension were the glucuronide adducts of both demethylated BZN and mono-oxygenated BZN. Based on the structural elucidation of the metabolites detected, we proposed an in vitro metabolic pathway of BZN, a new tubulin polymerization inhibitor.
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Affiliation(s)
- Florence Bourdon
- Univ Lille Nord de France, UDSL, EA GRIIOT, UFR Pharmacie, F-59000 Lille, France
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21
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Harskamp J, Britz-McKibbin P, Wilson JY. Functional screening of cytochrome P450 activity and uncoupling by capillary electrophoresis. Anal Chem 2011; 84:862-6. [PMID: 22148186 DOI: 10.1021/ac202787n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cytochrome P450s (CYPs) are functionally diverse monooxygenases responsible for oxidation of endogenous and xenobiotic compounds. The function of nonmammalian CYPs are largely unknown and tools for characterization limited. CYPs critical for xenobiotic metabolism are prone to catalytic cycle uncoupling resulting in reactive oxygen species (ROS) generation that is highly dependent on the specific CYP isoform and substrate interaction. This study describes the rapid assessment of the activity and coupling efficiency of CYPs using capillary electrophoresis with UV detection. The coupling efficiency of five zebrafish (Danio rerio) CYP1 isoforms with a series of fluorogenic substrate probes was determined by the rate of NADP(+) formation and compared with fluorescent product turnover rates. In most cases, NADP(+) formation significantly overestimated CYP1 catalytic activity for substrate O-dealkylation suggesting uncoupling. ROS production was confirmed by elevated hydrogen peroxide generation in poorly coupled reactions. Reactions with β-estradiol confirmed that CYP1A, 1C1, and 1C2 have greater catalytic activity and coupling efficiency; CYP1B1 and 1D1 had coupling efficiencies under 4%. This work highlights the wide disparity in uncoupling induced by unproductive substrate binding among different CYP isoforms.
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22
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De Bruyn T, Fattah S, Stieger B, Augustijns P, Annaert P. Sodium fluorescein is a probe substrate for hepatic drug transport mediated by OATP1B1 and OATP1B3. J Pharm Sci 2011; 100:5018-30. [DOI: 10.1002/jps.22694] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 06/10/2010] [Accepted: 06/14/2011] [Indexed: 01/11/2023]
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23
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Yang LP, Zhou ZW, Chen XW, Li CG, Sneed KB, Liang J, Zhou SF. Computational andin vitrostudies on the inhibitory effects of herbal compounds on human cytochrome P450 1A2. Xenobiotica 2011; 42:238-55. [DOI: 10.3109/00498254.2011.610833] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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24
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Traylor MJ, Ryan JD, Arnon ES, Dordick JS, Clark DS. Rapid and quantitative measurement of metabolic stability without chromatography or mass spectrometry. J Am Chem Soc 2011; 133:14476-9. [PMID: 21766815 DOI: 10.1021/ja203172c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolic stability measurements are a critical component of preclinical drug development. Available measurement strategies rely on chromatography and mass spectrometry, which are expensive and labor intensive. We have developed a general method to determine the metabolic stability of virtually any compound by quantifying cofactors in the mechanism of cytochrome P450 enzymes using fluorescence intensity measurements. While many previous studies have shown that simple measurements of cofactor depletion do not correlate with substrate conversion (i.e., metabolic stability) in P450 systems, the present work employs a reaction engineering approach to simplify the overall rate equation, thus allowing the accurate and quantitative determination of substrate depletion from simultaneous measurements of NADPH and oxygen depletion. This method combines the accuracy and generality of chromatography with the ease, throughput, and real-time capabilities of fluorescence.
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Affiliation(s)
- Matthew J Traylor
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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25
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Wang H, Kim RA, Sun D, Gao Y, Wang H, Zhu J, Chen C. Evaluation of the effects of 18 non-synonymous single-nucleotide polymorphisms of CYP450 2C19 onin vitrodrug inhibition potential by a fluorescence-based high-throughput assay. Xenobiotica 2011; 41:826-35. [DOI: 10.3109/00498254.2011.582893] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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26
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Tezuka Y, Morikawa K, Li F, Auw L, Awale S, Nobukawa T, Kadota S. Cytochrome P450 3A4 inhibitory constituents of the wood of Taxus yunnanensis. JOURNAL OF NATURAL PRODUCTS 2011; 74:102-105. [PMID: 21138310 DOI: 10.1021/np100665j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
From the aqueous extract of the wood of Taxus yunnanensis, which showed cytochrome P450 3A4 (CYP3A4) inhibition, a new isoflavan [(3S,4R)-4'-hydroxy-6,3'-dimethoxyisoflavan-4-ol (1)], a new degraded lignan [2,3-bis(hydroxymethyl)-7-hydroxy-6-methoxy-1-tetralone (2)], and a new lignan [(7R)-7-hydroxytaxiresinol (3)] were isolated, together with nine known lignans. Among the isolates obtained, α-conidendrin (12) showed strong CYP3A4 inhibition with an IC(50) value of 0.2 μM.
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Affiliation(s)
- Yasuhiro Tezuka
- Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
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27
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Salminen KA, Leppänen J, Venäläinen JI, Pasanen M, Auriola S, Juvonen RO, Raunio H. Simple, direct, and informative method for the assessment of CYP2C19 enzyme inactivation kinetics. Drug Metab Dispos 2010; 39:412-8. [PMID: 21148250 DOI: 10.1124/dmd.110.036376] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Many clinically relevant drug interactions involving cytochrome P450 inhibition are mediated by mechanism-based inactivation (MBI). Time-dependent inhibition is one of the major features distinguishing between reversible inhibition and MBI. It thus provides a useful screening approach for early drug interaction risk assessment. Accordingly, we developed an easy and informative fluorometric method for the assessment of CYP2C19 enzyme inactivation kinetics. Dibenzylfluorescein (DBF) is widely used as a profluorescent probe substrate for P450 activity and inhibition assays, but its use has been considered to be limited to traditional endpoint assays. We monitored CYP2C19-catalyzed metabolism of DBF using synthesized fluorescein benzyl ester and fluorescein benzyl ether along with commercially available fluorescein as intermediate standards. Furthermore, we demonstrated the use of DBF in a kinetic assay as a progress curve analysis for straightforward determination of whether a compound is a time-dependent inactivator of CYP2C19. The recombinant human CYP2C19 inactivation kinetics of isoniazid, ticlopidine, and tranylcypromine were evaluated, and their key kinetic parameters were measured from the same experiment. The known mechanism-based inactivators, isoniazid and ticlopidine, exhibited clear time-dependent inactivation with K(I) and k(inact) values of 250.5 ± 34 μM and 0.137 ± 0.006 min(-1) and 1.96 ± 0.5 μM and 0.135 ± 0.009 min(-1), respectively. Tranylcypromine did not display any time-dependent inhibition, which is consistent with its reported mechanism of competitive inhibition. In summary, DBF is suitable for use in the progress curve analysis approach and can be used as an initial screen to identify compounds that require more detailed investigations in drug interaction optimization.
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Affiliation(s)
- Kaisa A Salminen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland.
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28
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Scornaienchi ML, Thornton C, Willett KL, Wilson JY. Functional differences in the cytochrome P450 1 family enzymes from zebrafish (Danio rerio) using heterologously expressed proteins. Arch Biochem Biophys 2010; 502:17-22. [PMID: 20599672 PMCID: PMC2945726 DOI: 10.1016/j.abb.2010.06.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 06/11/2010] [Accepted: 06/15/2010] [Indexed: 11/29/2022]
Abstract
Mammalian cytochrome P450 1 (CYP1) genes are well characterized, but in other vertebrates only the functions of CYP1A genes have been well studied. We determined the catalytic activity of zebrafish CYP1A, CYP1B1, CYP1C1, CYP1C2, and CYP1D1 proteins using 11 fluorometric substrates and benzo[a]pyrene (BaP). The resorufin-based substrates, 7-ethoxyresorufin, 7-methoxyresorufin, and 7-benzyloxyresorufin, were well metabolized by all CYP1s except CYP1D1. CYP1A metabolized nearly all substrates tested, although rates for non-resorufin substrates were typically lower than resorufin-based substrates. Zebrafish CYP1s did not metabolize 7-benzyloxyquinoline, 3-[2-(N,N-diethyl-N-methylamino)ethyl]-7-methoxy-4-methylcoumarin or 7-methoxy-4-(aminomethyl)-coumarin. CYP1B1 and CYP1C2 had the highest rates of BaP metabolism. 3-Hydroxy-BaP was a prominent metabolite for all but CYP1D1. CYP1A showed broad specificity and had the highest metabolic rates for nearly all substrates. CYP1C1 and CYP1C2 had similar substrate specificity. CYP1D1 had very low activities for all substrates except BaP, and a different regioselectivity for BaP, suggesting that CYP1D1 function may be different from other CYP1s.
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Affiliation(s)
| | - Cammi Thornton
- Department of Pharmacology, University of Mississippi, University, MS, USA
| | | | - Joanna Y. Wilson
- Department of Biology, McMaster University, Hamilton, ON, Canada
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29
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Scornaienchi ML, Thornton C, Willett KL, Wilson JY. Cytochrome P450-mediated 17beta-estradiol metabolism in zebrafish (Danio rerio). J Endocrinol 2010; 206:317-25. [PMID: 20522564 PMCID: PMC8209656 DOI: 10.1677/joe-10-0075] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cytochrome P4501 (CYP1) and CYP3A proteins are primarily responsible for the metabolism of 17beta-estradiol (E(2)) in mammals. We have cloned and heterologously expressed CYP1A, CYP1B1, CYP1C1, CYP1C2, CYP1D1, and CYP3A65 from zebrafish (Danio rerio) to determine the CYP-mediated metabolism of E(2) in a non-mammalian species. Constructs of each CYP cDNA were created using a leader sequence from the bacterial ompA gene to allow appropriate expression in Escherichia coli without 5' modification of the gene. Membrane vesicles were purified, and functional CYP protein was verified using carbon monoxide difference spectra and fluorescent catalytic assays with the substrates 7-ethoxyresorufin and 7-benzyloxy-4-(trifluoromethyl)-coumarin. Rates of in vitro E(2) metabolism into 4-hydroxyE(2) (4-OHE(2)), 2-hydroxyE(2) (2-OHE(2)), and 16alpha-hydroxyE(1) (16alpha-OHE(1)) metabolites were determined by gas chromatography/mass spectrometry. The 2-OHE(2) metabolite was produced by all CYPs tested, while 4-OHE(2) was only detected following incubation with CYP1A, CYP1B1, CYP1C1, and CYP1C2. The 16alpha-OHE(1) metabolite was only produced by CYP1A. The highest rates of E(2) metabolism were from CYP1A and CYP1C1, followed by CYP1C2. CYP1B1, CYP1D1, and CYP3A65 had low rates of E(2) metabolism. E(2) metabolism by zebrafish CYP1A, CYP1C1, and CYP1C2 produced similar ratios of 4-OHE(2) to 2-OHE(2) as previous studies with mammalian CYP1As. CYP1B1 formed the highest ratio of 4-OHE(2) to 2-OHE(2) metabolites. Contrary to mammals, these results suggest that fish CYP1A and CYP1C proteins are primarily responsible for E(2) metabolism, with only minor contributions from CYP3A65 and CYP1B1. Similar to mammals, 2-OHE(2) is the predominant metabolite from CYP-mediated E(2) metabolism in fish, suggesting that all vertebrate species produce the same major E(2) metabolite.
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Affiliation(s)
- Marcus L Scornaienchi
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S4K1
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30
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Liu D, Gao Y, Wang H, Zi J, Huang H, Ji J, Zhou R, Nan Y, Wang S, Zheng X, Zhu J, Cui Y, Chen C. Evaluation of the Effects of Cytochrome P450 Nonsynonymous Single-Nucleotide Polymorphisms on Tanshinol Borneol Ester Metabolism and Inhibition Potential. Drug Metab Dispos 2010; 38:2259-65. [DOI: 10.1124/dmd.110.034439] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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31
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Van BEUSEKOM CD, SCHIPPER L, FINK-GREMMELS J. Cytochrome P450-mediated hepatic metabolism of new fluorescent substrates in cats and dogs. J Vet Pharmacol Ther 2010; 33:519-27. [DOI: 10.1111/j.1365-2885.2010.01199.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Bednarczyk D. Fluorescence-based assays for the assessment of drug interaction with the human transporters OATP1B1 and OATP1B3. Anal Biochem 2010; 405:50-8. [PMID: 20540932 DOI: 10.1016/j.ab.2010.06.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/31/2010] [Accepted: 06/04/2010] [Indexed: 11/17/2022]
Abstract
Hepatic disposition plays a significant role in the pharmacokinetics and pharmacodynamics of a variety of drugs. Sinusoidal membrane transporters have been shown to participate in the hepatic disposition of many pharmaceuticals. Two sinusoidal membrane transporters with an established role in hepatic disposition are OATP1B1 and OATP1B3 (organic anion-transporting polypeptides 1B1 and 1B3, respectively). OATP1B1 and OATP1B3 have been implicated in the hepatic uptake of statin drugs, and polymorphisms linked to OATP1B1 have been associated with deleterious patient endpoints. As a result, OATP1B1 and OATP1B3 represent sites for potential drug-drug interactions. Numerous methods exist for identifying potential drug-drug interactions with transporters. However, relatively few offer the convenience and speed of fluorescence-based assays. Here a fluorescence-based assay was developed for measuring the OATP1B1- and OATP1B3-mediated transport of 8-fluorescein-cAMP (8-FcA). The OATP1B1- and OATP1B3-mediated transport of 8-FcA was time dependent and saturable (K(m)=2.9 and 1.8 microM, V(max)=0.20 and 0.33 pmol/min/cm(2), respectively). Molecules known to interact with OATPs, including cyclosporin A, rifampicin, and glibenclamide, each demonstrated concentration-dependent inhibition of 8-FcA transport by OATP1B1 and OATP1B3. The in vitro fluorescence-based assays described here using 8-FcA as the substrate are convenient and rapid and have utility in screening drug candidates for potential drug-drug interactions with OATP1B1 and OATP1B3.
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Bártíková H, Krízová V, Stepnicková M, Lamka J, Kubícek V, Skálová L, Szotáková B. Activities of biotransformation enzymes and flubendazole metabolism in lambs (Ovis aries): effect of gender and flubendazole therapy. Pharmacol Rep 2010; 62:362-73. [PMID: 20508292 DOI: 10.1016/s1734-1140(10)70276-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 09/28/2009] [Indexed: 10/25/2022]
Abstract
The effect of flubendazole (FLU) therapy on in vitro FLU biotransformation and the activities of selected biotransformation enzymes were investigated in male and female lambs. Four experimental groups were used: control (untreated) ewes and rams and FLU-treated ewes and rams (orally, 15 mg/kg per day, for three consecutive days). Subcellular fractions were prepared from liver and intestinal mucosa 24 h after the final dosage was administered. Activities of cytochromes P450 (CYP), flavine monooxygenases (FMO), carbonyl reducing enzymes, UDP-glucuronosyl transferase (UGT) and glutathione S-transferase were tested. Significant gender differences were observed for FMO-mediated activity (2-fold higher in ram lambs) and UGT activity (up to 30% higher in ewe lambs), but no gender differences were observed in FLU metabolism. FLU-treatment of lambs moderately changed the activities of some CYPs, FMO, and UGT in liver microsomes. In vitro FLU reduction was not altered in the liver, but was slightly higher in the small intestine of FLU pre-treated lambs. This correlated with the higher carbonyl reductase activities measured in the gut mucosa of these animals.
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Affiliation(s)
- Hana Bártíková
- Faculty of Pharmacy, Charles University, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
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Litten BA, Smith R, Banfield E. An Automated 1536-Well Microplate Format Cytochrome P450 Inhibition Assay Using a Tecan Freedom EVO Workstation with Integrated Innovadyne Nanodrop II Dispenser. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.jala.2009.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A Tecan EVO Workstation and Innovadyne Nanodrop II liquid dispenser have been integrated to provide an automated miniaturized cytochrome P450 inhibition assay, using 1536-well plate technology. The Tecan EVO was used to perform larger volume bulk reagent and compound dilution operations along with plate manipulations using the Tecan Robotic Manipulator. All reagent additions to the 1536-well microplates were performed exclusively by the Nanodrop dispenser, which is capable of accurate and precise pipetting at volumes as low as 100 nL. Miniaturization from 96- to 1536-well plate formats has enabled a fourfold increase in P450 inhibition assay capacity, while reducing reagent costs by approximately 20-fold.
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Affiliation(s)
| | - Robin Smith
- AstraZeneca plc, Alderley Park, Macclesfield, Cheshire, UK
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35
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BÃRTÃKOVà H, KÅÃŽOVà V, LAMKA J, KUBÃÄEK V, SKÃLOVà L, SZOTÃKOVà B. Flubendazole metabolism and biotransformation enzymes activities in healthy sheep and sheep with haemonchosis. J Vet Pharmacol Ther 2010; 33:56-62. [DOI: 10.1111/j.1365-2885.2009.01112.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Mori K, Hashimoto H, Takatsu H, Tsuda-Tsukimoto M, Kume T. Cocktail-substrate assay system for mechanism-based inhibition of CYP2C9, CYP2D6, and CYP3A using human liver microsomes at an early stage of drug development. Xenobiotica 2009; 39:415-22. [PMID: 19480547 DOI: 10.1080/00498250902822204] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
We established a mechanism-based inhibition cocktail-substrate assay system using human liver microsomes and drug-probe substrates that enabled simultaneous estimation of the inactivation of main cytochrome P450 (CYP) enzymes, CYP2C9, CYP2D6, and CYP3A, in drug metabolism. The inactivation kinetic parameters of typical mechanism-based inhibitors, tienilic acid, paroxetine, and erythromycin, for each enzyme in the cocktail-substrate assay were almost in agreement with the values obtained in the single-substrate assay. Using this system, we confirmed that multiple CYP inactivation caused by mechanism-based inhibitors such as isoniazid and amiodarone could be detected simultaneously. Mechanism-based inhibition potency can be estimated by the determination of the observed inactivation rate constants (k(obs)) at a single concentration of test compounds because the k(obs) of eleven CYP3A inactivators at 10 microM in the assay system nearly corresponded to k(inact)/K(I) values, an indicator of a compound's propensity to alter the activity of a CYP in vivo (R(2) = 0.97). Therefore, this cocktail-substrate assay is considered to be a powerful tool for evaluating mechanism-based inhibition at an early stage of drug development.
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Affiliation(s)
- K Mori
- Drug Metabolism and Pharmacokinetic Research Laboratory, Mitsubishi Tanabe Pharma Corporation, Toda, Japan
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37
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Mei L, Zhang L, Dai R. An inhibition study of beauvericin on human and rat cytochrome P450 enzymes and its pharmacokinetics in rats. J Enzyme Inhib Med Chem 2009; 24:753-62. [DOI: 10.1080/14756360802362041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Li Mei
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510663, China
| | - Lixin Zhang
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Renke Dai
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510663, China
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38
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Jones BC, Middleton DS, Youdim K. 6 Cytochrome P450 Metabolism and Inhibition: Analysis for Drug Discovery. PROGRESS IN MEDICINAL CHEMISTRY 2009; 47:239-63. [DOI: 10.1016/s0079-6468(08)00206-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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39
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Locuson CW, Ethell BT, Voice M, Lee D, Feenstra KL. Evaluation of Escherichia coli membrane preparations of canine CYP1A1, 2B11, 2C21, 2C41, 2D15, 3A12, and 3A26 with coexpressed canine cytochrome P450 reductase. Drug Metab Dispos 2008; 37:457-61. [PMID: 19074522 DOI: 10.1124/dmd.108.025312] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The preparation of bacterial membranes ("Bactosomes") containing expressed canine (beagle) hepatic cytochromes P450 (P450s) is described. cDNAs from seven canine P450s were subcloned into inducible expression plasmids and, for the first time, cotransformed and expressed with a canine P450 oxidoreductase in Escherichia coli to produce active, full-length, native sequence P450s. Enzyme expression levels, although variable, were generally sufficient to enable short incubation times and to limit the total protein present in enzyme incubations. Steady-state kinetics of CYP1A1, 2C21, and 2D15 Bactosomes demonstrated similarities with dog liver microsomes or Baculosomes. However, 3A12 lacked substrate inhibition in the formation of 1'-OH midazolam, and 2B11 displayed non-Michaelis-Menten kinetics, suggesting possible differences in protein interaction effects. In monitoring the metabolites of common P450 substrates, phenacetin deethylation, temazepam demethylation, and bufuralol 1'-hydroxylation were shown to be relatively selective reactions catalyzed by CYP1A1, 2B11, and 2D15, respectively. 1'-OH midazolam was formed in higher quantities by CYP2B11 and 2C21 than by 3A12, raising questions about the use of midazolam as a CYP3A12 probe in vivo. In summary, a panel of recombinant P450s was produced to make up for the lack of commercially available canine P450 isoforms. The Bactosomes are expected to facilitate reaction phenotyping and metabolic drug-drug interaction assessment in canine drug development and to enable the study of interspecies differences in P450-mediated drug metabolism.
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Affiliation(s)
- Charles W Locuson
- Pfizer Animal Health, Pfizer, Inc., Veterinary Medicine Research and Development, Metabolism and Safety, 333 Portage Street, KZO-300-413, Kalamazoo, MI 49001, USA.
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40
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Fry JR, Hammond AH, Jassi KL, Bass AE, Bruce G, Laughton C, Shaw PN, Bylov IE, Kovalenko SM. Selectivity of 7-alkoxycoumarins as probe substrates for rat hepatic cytochrome P450 forms is influenced by the substitution pattern on the coumarin nucleus. Xenobiotica 2008; 34:707-22. [PMID: 15690760 DOI: 10.1080/00498250400003463] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
1. The O-dealkylation of 7-alkoxycoumarins is widely used as an assay to characterize cytochrome P450 (CYP) activity. These substrates can also undergo oxidative attack at additional sites on the coumarin nucleus, which may influence their apparent selectivity for particular CYP forms. 2. Accordingly, the effect of blockade of these additional sites was investigated on the selectivity towards rat hepatic CYP forms, with emphasis on the CYP1A and 2B forms. 3. Blockade of the 3-/4- and 6-positions resulted in substrates for which the CYP1A1/2 selectivity of the unsubstituted 7-alkoxycoumarins was altered to a CYP2B selectivity; this was achieved with little overall change in the molecular dimensions of the substrate. Limited analysis of other inducible CYP forms indicated at most only small effects of structure modification on activity. 4. The findings suggest that the sensitivity of probe substrates for CYP forms may be limited by the occurrence of competing side reactions of the substrate, and that better probes may be derived by blocking the sites of these side reactions.
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Affiliation(s)
- J R Fry
- School of Biomedical Sciences, Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
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41
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An automated, high-throughput, 384 well Cytochrome P450 cocktail IC50 assay using a rapid resolution LC-MS/MS end-point. J Pharm Biomed Anal 2008; 48:92-9. [PMID: 18584988 DOI: 10.1016/j.jpba.2008.05.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 05/01/2008] [Accepted: 05/09/2008] [Indexed: 11/23/2022]
Abstract
The current study focused on the development of an automated IC50 cocktail assay in a miniaturized 384 well assay format. This was developed in combination with a significantly shorter high pressure liquid chromatography (HPLC) separation and liquid chromatography-mass spectrometry (LC-MS/MS) run-time; than those currently reported in the literature. The 384-well assay used human liver microsomes in conjunction with a cocktail of probe substrates metabolized by the five major CYPs (tacrine for CYP1A2, diclofenac for CYP2C9, (S)-mephenytoin for CYP2C19, dextromethorphan for CYP2D6 and midazolam for CYP3A4). To validate the usefulness of the automated and analytical methodologies, IC50 determinations were performed for a series of test compounds known to exhibit inhibition across these five major P450s. Eight compounds (sertraline, disulfuram, ticlopidine fluconazole, fluvoxamine, ketoconazole, miconazole, paroxetine, flunitrazepam) were studied as part of a cocktail assay, and against each CYPs individually. The data showed that the IC50s generated with cocktail incubations did not differ to a great extent from those obtained in the single probe experiments and hence unlikely to significantly influence the predicted clinical DDI risk. In addition the present method offered a significant advantage over some of the existing cocktail analytical methodology in that separation can be achieved with run times as short as 1 min without compromising data integrity. Although numerous studies have been reported to measure CYP inhibition in a cocktail format the need to support growing discovery libraries not only relies on higher throughput assays but quicker analytical run times. The current study reports a miniaturized high-throughput cocktail IC50 assay, in conjunction with a robust, rapid resolution LC-MS/MS end-point offered increased sample throughput without compromising analytical sensitivity or analyte resolution.
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42
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Houck KA, Kavlock RJ. Understanding mechanisms of toxicity: insights from drug discovery research. Toxicol Appl Pharmacol 2007; 227:163-78. [PMID: 18063003 DOI: 10.1016/j.taap.2007.10.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 09/28/2007] [Accepted: 10/11/2007] [Indexed: 12/18/2022]
Abstract
Toxicology continues to rely heavily on use of animal testing for prediction of potential for toxicity in humans. Where mechanisms of toxicity have been elucidated, for example endocrine disruption by xenoestrogens binding to the estrogen receptor, in vitro assays have been developed as surrogate assays for toxicity prediction. This mechanistic information can be combined with other data such as exposure levels to inform a risk assessment for the chemical. However, there remains a paucity of such mechanistic assays due at least in part to lack of methods to determine specific mechanisms of toxicity for many toxicants. A means to address this deficiency lies in utilization of a vast repertoire of tools developed by the drug discovery industry for interrogating the bioactivity of chemicals. This review describes the application of high-throughput screening assays as experimental tools for profiling chemicals for potential for toxicity and understanding underlying mechanisms. The accessibility of broad panels of assays covering an array of protein families permits evaluation of chemicals for their ability to directly modulate many potential targets of toxicity. In addition, advances in cell-based screening have yielded tools capable of reporting the effects of chemicals on numerous critical cell signaling pathways and cell health parameters. Novel, more complex cellular systems are being used to model mammalian tissues and the consequences of compound treatment. Finally, high-throughput technology is being applied to model organism screens to understand mechanisms of toxicity. However, a number of formidable challenges to these methods remain to be overcome before they are widely applicable. Integration of successful approaches will contribute towards building a systems approach to toxicology that will provide mechanistic understanding of the effects of chemicals on biological systems and aid in rationale risk assessments.
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Affiliation(s)
- Keith A Houck
- National Center for Computational Toxicology, Office Research and Development, United Stated Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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43
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Savlík M, Polácková L, Szotáková B, Lamka J, Velík J, Skálová L. Activities of biotransformation enzymes in pheasant (Phasianus colchicus) and their modulation by in vivo administration of mebendazole and flubendazole. Res Vet Sci 2007; 83:20-6. [PMID: 17316720 DOI: 10.1016/j.rvsc.2006.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 09/10/2006] [Accepted: 10/02/2006] [Indexed: 11/23/2022]
Abstract
Basal activities of certain pheasant hepatic and intestinal biotransformation enzymes and modulation of their activities by anthelmintics flubendazole (FLBZ) and mebendazole (MBZ) were investigated in subcellular fractions that were prepared from liver and small intestine of control and FLBZ or MBZ treated birds. Several oxidation, reduction and conjugation enzyme activities were assessed. In the liver, treatment of pheasants by FLBZ or MBZ caused very slight or no changes in monooxygenase activities and conjugation enzymes. More significative changes were detected in small intestine. Metyrapone and daunorubicin reductase activities were increased by both substances in the liver. This is the first evidence that certain benzimidazoles modulate reductases of carbonyl group. With respect to the relatively slight extent of the changes caused by FLBZ or MBZ we can assume that repeated administration of therapeutic doses of both FLBZ and MBZ has probably no serious influence on pheasant biotransformation enzyme system.
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Affiliation(s)
- M Savlík
- Department of Biochemical Sciences, Faculty of Pharmacy, Charles University, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
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44
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Xia ZL, Ying JY, Sheng R, Zeng S, Hu YZ, Yao TW. In vitro metabolism of BYZX in human liver microsomes and the structural elucidation of metabolite by liquid chromatography-mass spectrometry method. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 857:266-74. [PMID: 17709305 DOI: 10.1016/j.jchromb.2007.07.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 06/28/2007] [Accepted: 07/20/2007] [Indexed: 11/17/2022]
Abstract
In vitro phase I metabolism of BYZX, a novel central-acting cholinesterase inhibitor for the treatment of the symptoms of Alzheimer's disease, was studied in human liver microsomes (HLM) and the metabolite formation pathways were investigated by chemical inhibition experiments and correlation analysis. The residual concentration of substrate and the metabolite formed in incubate were determined by HPLC method. The calibration curves of BYZX were linear over the concentration range from 5.07 microM to 200.74 microM. The relative standard deviations of within day and between day were less than 5% (n=5). The limit of detection (LOD) was 0.18 microg/mL (S/N=3) and the limit of quantification (LOQ) was 0.55 microg/mL (R.S.D.=5.2%, n=5). The determination recoveries of BYZX were in the range of 98.2-104.8%. The apparent K(m) of BYZX in HLM was 53.25+/-17.2 microM, the V(max) was 0.94+/-0.77 microM/min/mg protein, and the intrinsic clearance value (Cl(int)) was 0.018+/-0.02 mL/min/mg protein. Ketoconazole and cyclosporin A were the most potent inhibitors on BYZX metabolism in HLM with IC(50) being 0.89 microM and 18.17 microM, respectively. And the inhibition constant (K(i)) of ketoconazole was 0.42 microM. The metabolite of BYZX was N-des-ethyl-BYZX elucidated by LC-MS-MS. The results demonstrated that the developed HPLC method was reliability, simple technique, and was applicable to be used for the researches of in vitro metabolism of BYZX. CYP3A4 was the major isozyme responsible for BYZX metabolism; N-dealkylation was the major metabolic pathway of BYZX. The predominant metabolite of BYZX was N-des-ethyl-BYZX detected in vitro phase I metabolism in HLM.
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Affiliation(s)
- Zong-Ling Xia
- College of Pharmaceutical Sciences, Zhejiang University, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China
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45
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Di Marco A, Cellucci A, Chaudhary A, Fonsi M, Laufer R. High-Throughput Radiometric CYP2C19 Inhibition Assay Using Tritiated (S)-Mephenytoin. Drug Metab Dispos 2007; 35:1737-43. [PMID: 17600081 DOI: 10.1124/dmd.107.016345] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
A rapid and sensitive radiometric assay for assessing the potential of drugs to inhibit cytochrome P450 (P450) 2C19 in human liver microsomes is described. The new assay, which does not require high-performance liquid chromatography (HPLC) separation or mass spectrometric detection, is based on the release of tritium as tritiated water that occurs upon CYP2C19-mediated 4'-hydroxylation of (S)-mephenytoin labeled with tritium in the 4' position. Because this reaction is subject to an NIH shift, tritium was also introduced into the 3'- and 5'-positions of the tracer to enhance formation of a tritiated water product. Tritiated water was separated from the substrate using 96-well solid-phase extraction plates. The reaction is NADPH-dependent and sensitive to CYP2C19 inhibitors. IC(50) values for 15 diverse drugs differed less than 2.5-fold from those determined by quantification of the unlabeled 4'-hydroxy-(S)-mephenytoin product, using HPLC coupled to mass spectrometric detection. All of the steps of the new assay, namely incubation, product separation, and radioactivity counting, are performed in a 96-well format and can be automated. This assay represents a non-HPLC, high-throughput version of the classic (S)-mephenytoin 4'-hydroxylation assay, which is the most widely used method to assess the potential for CYP2C19 inhibition of new chemical entities.
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Affiliation(s)
- Annalise Di Marco
- Department of Pharmacology, Istituto di Recherche di Biologia Molecolare, Merck Research Laboratories, Rome, Italy
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46
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Jones DR, Ekins S, Li L, Hall SD. Computational Approaches That Predict Metabolic Intermediate Complex Formation with CYP3A4 (+b5). Drug Metab Dispos 2007; 35:1466-75. [PMID: 17537872 DOI: 10.1124/dmd.106.014613] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Some mechanism-based inhibitors cause irreversible inhibition by forming a metabolic intermediate complex (MIC) with cytochrome P450. In the present study, 54 molecules (substrates of CYP3A and amine-containing compounds that are not known substrates of CYP3A) were spectrophotometrically assessed for their propensity to cause MIC formation with recombinant CYP3A4 (+b(5)). Comparisons of common physicochemical properties showed that mean (+/-S.D.) mol. wt. of MIC-forming compounds was significantly greater than mean mol. wt. of non-MIC-forming compounds, 472 (+/-173) versus 307 (+/-137), respectively. Computational pharmacophores, logistic regression, and recursive partitioning (RP) approaches were applied to predict MIC formation from molecular structure and to generate a quantitative structure activity relationship. A pharmacophore built with SKF-525A (2-diethylaminoethyl 2:2-diphenylvalerate hydrochloride), erythromycin, amprenavir, and norverapamil indicated that four hydrophobic features and a hydrogen bond acceptor were important for these MIC-forming compounds. Two different RP methods using either simple descriptors or 2D augmented atom descriptors indicated that hydro-phobic and hydrogen bond acceptor features were required for MIC formation. Both of these RP methods correctly predicted the MIC formation status with CYP3A4 for 10 of 12 literature molecules in an independent test set. Logistic multiple regression and a third classification tree model predicted 11 of 12 molecules correctly. Both models possessed a hydrogen bond acceptor and represent an approach for predicting CYP3A4 MIC formation that can be improved using more data and molecular descriptors. The preliminary pharmacophores provide structural insights that complement those for CYP3A4 inhibitors and substrates.
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Affiliation(s)
- David R Jones
- Indiana University School of Medicine, Department of Medicine, Division of Clinical Pharmacology, Wishard Memorial Hospital, Myers Bldg. W7123, Indianapolis, IN 46220, USA
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47
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Skálová L, Krízová V, Cvilink V, Szotáková B, Storkánová L, Velík J, Lamka J. Mouflon (Ovis musimon) dicrocoeliosis: Effects of parasitosis on the activities of biotransformation enzymes and albendazole metabolism in liver. Vet Parasitol 2007; 146:254-62. [PMID: 17386978 DOI: 10.1016/j.vetpar.2007.02.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Revised: 02/16/2007] [Accepted: 02/21/2007] [Indexed: 11/15/2022]
Abstract
Parasitic infections can modify the host's ability to metabolize drugs and other xenobiotics by altering the biotransformation enzymes; these changes may have various pharmacological, toxicological or physiological consequences. In our study, several activities of liver biotransformation enzymes and in vitro metabolism of albendazole (ABZ) were tested and compared in non-infected mouflons (Ovis musimon) and in mouflons infected by lancet fluke (Dicrocoelium dendriticum). Subcellular fractions of liver homogenates were isolated from 5+5 mouflon rams (1-year-old) parasitologically negative or naturally infected by fluke. From the eight enzyme activities that were assayed, only two activities significantly differ in the case of Dicrocoelium-infected versus non-infected animals. In infected mouflons, a significant increase (53%) of thiobenzamide-S-oxidase (TBSO) activity, corresponding mainly to the activity of flavine monooxygenase (FMO), and significant decrease (60%) of glutathione-S-transferase (GST) activity was observed. In addition, dicrocoeliosis caused the enhancement of ABZ hepatic biotransformation. The velocity of the formation of (+)-ABZ sulfoxide and ABZ sulfone was significantly increased. However, the shifts in ABZ biotransformation were very mild that undesirable alterations in ABZ pharmacokinetic are not expected. From this point of view, the use of ABZ in the therapy of mouflon dicrocoeliosis in young animals can be recommended. The treatment of the same mouflons by other drugs that are mainly conjugated with glutathione, seems to be more problematic; hence, all consequences of documented reduced GST activity should be accounted.
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Affiliation(s)
- L Skálová
- Charles University in Prague, Faculty of Pharmacy, Heyrovského 1203, Hradec Králové, Czech Republic.
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48
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Watanabe A, Nakamura K, Okudaira N, Okazaki O, Sudo KI. Risk Assessment for Drug-Drug Interaction Caused by Metabolism-Based Inhibition of CYP3A Using Automated in Vitro Assay Systems and Its Application in the Early Drug Discovery Process. Drug Metab Dispos 2007; 35:1232-8. [PMID: 17392390 DOI: 10.1124/dmd.107.015016] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The CYP3A family is a major drug metabolism enzyme in humans. Metabolism-based inhibition of CYP3A might cause clinically significant drug-drug interactions (DDIs). To assess the risk of DDIs caused by metabolism-based inhibition (MBI) of CYP3A, we established an automated single time- and concentration-dependent inhibition assay. To create a diagram to assess DDI risk of compounds in the early discovery stage, we classified 171 marketed drugs by the possibility of the occurrence of in vivo DDI caused by MBI from the relationship between the inactivation activity determined in the MBI screening, the therapeutic blood or plasma concentration, and the in vivo DDI information. This analysis revealed that the DDI risk depends on both the MBI potential and the blood concentration of a compound, and provided the criteria of the DDI risk. In the assay, three compounds (midazolam, nifedipine, and testosterone) were compared as CYP3A probe substrates. The results show that the evaluation for MBI does not depend on the probe substrates used in the assay. In addition, we established an automated assay to distinguish quasi-irreversible and irreversible binding to CYP3A in which the quasi-irreversible inhibitors such as diltiazem, verapamil, and nicardipine were dissociated from CYP3A by the addition of potassium ferricyanide, whereas the irreversible inhibitors such as clozapine, delavirdine, and mibefradil were not. It provides useful information related to chemical structures likely to cause MBI. By using these MBI assays supported by an extensive database of marketed compounds, a systematic MBI evaluation paradigm was established and has been incorporated into our drug discovery process.
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Affiliation(s)
- Akiko Watanabe
- Drug Metabolism and Physicochemistry Research Laboratory, Daiichi Pharmaceutical Co., Ltd., Tokyo, Japan.
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Kool J, van Liempd SM, van Rossum H, van Elswijk DA, Irth H, Commandeur JNM, Vermeulen NPE. Development of three parallel cytochrome P450 enzyme affinity detection systems coupled on-line to gradient high-performance liquid chromatography. Drug Metab Dispos 2007; 35:640-8. [PMID: 17251308 DOI: 10.1124/dmd.106.012245] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A high resolution screening (HRS) technology is described, in which gradient high-performance liquid chromatography (HPLC) is connected on-line to three parallel placed bioaffinity detection systems containing mammalian cytochromes P450 (P450s). The three so-called enzyme affinity detection (EAD) systems contained, respectively, liver microsomes from rats induced by beta-naphthoflavone (CYP1A activity), phenobarbital (CYP2B activity), and dexamethasone (CYP3A activity). Each P450-EAD system was optimized for enzyme, substrate, and organic modifier (isopropyl alcohol, methanol, and acetonitrile) in flow injection analysis mode. Characteristic P450 ligands were used to validate the P450-EAD systems. IC(50) values of the ligands were measured and found to be similar to those obtained with conventional microtiter plate reader assays. Detection limits (n = 3; signal-to-noise ratio = 3) of potent inhibitors ranged from 1 to 3 pmol for CYP1A activity, 4 to 17 pmol for CYP2B activity, and 4 to 15 pmol for CYP3A activity. The three optimized P450-EAD systems were subsequently coupled to gradient HPLC and used to screen compound mixtures for individual ligands. Finally, to increase analysis efficiency, a HRS system was constructed in which all three P450-EAD systems were coupled on-line and in parallel to gradient HPLC. The triple parallelized P450-EAD system was shown to enable rapid profiling of individual components in complex mixtures for inhibitory activity to three different P450s.
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Affiliation(s)
- Jeroen Kool
- Vrije Universiteit, Department of Pharmacochemistry, LACDR-Division of Molecular Toxicology, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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Li X, Chen X, Li Q, Wang L, Zhong D. Validated method for rapid inhibition screening of six cytochrome P450 enzymes by liquid chromatography-tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 852:128-37. [PMID: 17267297 DOI: 10.1016/j.jchromb.2007.01.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2006] [Revised: 12/30/2006] [Accepted: 01/05/2007] [Indexed: 01/28/2023]
Abstract
In vitro drug interaction data can be used in guiding clinical interaction studies, or, the design of new candidates. To make such a claim, it must be assured that the in vitro data obtained is confident. To meet this need, a rapid liquid chromatography-tandem mass spectrometry (LC/MS/MS) method has been validated and employed for routine screening of new chemical entities for inhibition of six major human cytochrome P450 (CYP) isoforms using cDNA-expressed CYPs. Probe substrates were used near the Michaelis-Menten constant (K(m)) concentration values for CYP1A2 (phenacetin), CYP2C9 (tolbutamide), CYP2C19 (S-mephenytoin), CYP2D6 (dextromethorphan) and CYP3A4 (midazolam and dextromethorphan). The major metabolites of CYP-specific probe substrates were quantified. The LC/MS/MS method was found to be accurate and precise within the linear range of 1.0-2000 ng/ml for each analyte in enzyme incubation mixture. The lower limit of quantification (LLOQ) was 1.0 ng/ml. The limit of detection (LOD) for the tested analytes was 0.48 ng/ml or better based on signal-to-noise ratio >3. The inhibition potential of the six CYP isoforms has been evaluated using their known selective inhibitors. The 50% inhibitory concentrations (IC(50) values) measured by this method demonstrated high precision and are consistent with the literature values.
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Affiliation(s)
- Xiaoyan Li
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 646 Songtao Road, Shanghai 201203, China
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