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Jochum K, Miccoli A, Sommersdorf C, Poetz O, Braeuning A, Tralau T, Marx-Stoelting P. Comparative case study on NAMs: towards enhancing specific target organ toxicity analysis. Arch Toxicol 2024:10.1007/s00204-024-03839-7. [PMID: 39207506 DOI: 10.1007/s00204-024-03839-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Accepted: 08/08/2024] [Indexed: 09/04/2024]
Abstract
Traditional risk assessment methodologies in toxicology have relied upon animal testing, despite concerns regarding interspecies consistency, reproducibility, costs, and ethics. New Approach Methodologies (NAMs), including cell culture and multi-level omics analyses, hold promise by providing mechanistic information rather than assessing organ pathology. However, NAMs face limitations, like lacking a whole organism and restricted toxicokinetic interactions. This is an inherent challenge when it comes to the use of omics data from in vitro studies for the prediction of organ toxicity in vivo. One solution in this context are comparative in vitro-in vivo studies as they allow for a more detailed assessment of the transferability of the respective NAM data. Hence, hepatotoxic and nephrotoxic pesticide active substances were tested in human cell lines and the results subsequently related to the biology underlying established effects in vivo. To this end, substances were tested in HepaRG and RPTEC/tERT1 cells at non-cytotoxic concentrations and analyzed for effects on the transcriptome and parts of the proteome using quantitative real-time PCR arrays and multiplexed microsphere-based sandwich immunoassays, respectively. Transcriptomics data were analyzed using three bioinformatics tools. Where possible, in vitro endpoints were connected to in vivo observations. Targeted protein analysis revealed various affected pathways, with generally fewer effects present in RPTEC/tERT1. The strongest transcriptional impact was observed for Chlorotoluron in HepaRG cells (increased CYP1A1 and CYP1A2 expression). A comprehensive comparison of early cellular responses with data from in vivo studies revealed that transcriptomics outperformed targeted protein analysis, correctly predicting up to 50% of in vivo effects.
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Affiliation(s)
- Kristina Jochum
- Department of Pesticides Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Andrea Miccoli
- Department of Pesticides Safety, German Federal Institute for Risk Assessment, Berlin, Germany
- Institute for Marine Biological Resources and Biotechnology (IRBIM), National Research Council, Ancona, Italy
- Department of Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | | | - Oliver Poetz
- Signatope GmbH, Tübingen, Germany
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Albert Braeuning
- Department of Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Tewes Tralau
- Department of Pesticides Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Philip Marx-Stoelting
- Department of Pesticides Safety, German Federal Institute for Risk Assessment, Berlin, Germany.
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2
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Ip BC, Madnick SJ, Zheng S, van Tongeren TCA, Hall SJ, Li H, Martin S, Spriggs S, Carmichael P, Chen W, Ames D, Breitweiser LA, Pence HE, Bowling AJ, Johnson KJ, Cubberley R, Morgan JR, Boekelheide K. Development of a human liver microphysiological coculture system for higher throughput chemical safety assessment. Toxicol Sci 2024; 199:227-245. [PMID: 38335931 PMCID: PMC11131024 DOI: 10.1093/toxsci/kfae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2024] Open
Abstract
Chemicals in the systemic circulation can undergo hepatic xenobiotic metabolism, generate metabolites, and exhibit altered toxicity compared with their parent compounds. This article describes a 2-chamber liver-organ coculture model in a higher-throughput 96-well format for the determination of toxicity on target tissues in the presence of physiologically relevant human liver metabolism. This 2-chamber system is a hydrogel formed within each well consisting of a central well (target tissue) and an outer ring-shaped trough (human liver tissue). The target tissue chamber can be configured to accommodate a three-dimensional (3D) spheroid-shaped microtissue, or a 2-dimensional (2D) cell monolayer. Culture medium and compounds freely diffuse between the 2 chambers. Human-differentiated HepaRG liver cells are used to form the 3D human liver microtissues, which displayed robust protein expression of liver biomarkers (albumin, asialoglycoprotein receptor, Phase I cytochrome P450 [CYP3A4] enzyme, multidrug resistance-associated protein 2 transporter, and glycogen), and exhibited Phase I/II enzyme activities over the course of 17 days. Histological and ultrastructural analyses confirmed that the HepaRG microtissues presented a differentiated hepatocyte phenotype, including abundant mitochondria, endoplasmic reticulum, and bile canaliculi. Liver microtissue zonation characteristics could be easily modulated by maturation in different media supplements. Furthermore, our proof-of-concept study demonstrated the efficacy of this coculture model in evaluating testosterone-mediated androgen receptor responses in the presence of human liver metabolism. This liver-organ coculture system provides a practical, higher-throughput testing platform for metabolism-dependent bioactivity assessment of drugs/chemicals to better recapitulate the biological effects and potential toxicity of human exposures.
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Affiliation(s)
- Blanche C Ip
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
- Center for Alternatives to Animals in Testing, Brown University, Providence, Rhode Island 02903, USA
| | - Samantha J Madnick
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
- Center for Alternatives to Animals in Testing, Brown University, Providence, Rhode Island 02903, USA
| | - Sophia Zheng
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
| | - Tessa C A van Tongeren
- Division of Toxicology, Wageningen University and Research, 6700 EA Wageningen, The Netherlands
| | - Susan J Hall
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
| | - Hui Li
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
| | - Suzanne Martin
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom
| | - Sandrine Spriggs
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom
| | - Paul Carmichael
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom
| | - Wei Chen
- Corteva, Inc, Indianapolis, Indiana 46268, USA
| | - David Ames
- Corteva, Inc, Indianapolis, Indiana 46268, USA
| | | | | | | | | | - Richard Cubberley
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom
| | - Jeffrey R Morgan
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
- Center for Alternatives to Animals in Testing, Brown University, Providence, Rhode Island 02903, USA
| | - Kim Boekelheide
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
- Center for Alternatives to Animals in Testing, Brown University, Providence, Rhode Island 02903, USA
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3
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Yamazoe Y, Murayama N, Yoshinari K. Refined CYP2E1 ∗ Template ∗∗ system to decipher the ligand-interactions. Drug Metab Pharmacokinet 2021; 41:100413. [PMID: 34673327 DOI: 10.1016/j.dmpk.2021.100413] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 05/16/2021] [Accepted: 06/23/2021] [Indexed: 10/20/2022]
Abstract
A Template system for a prediction of human CYP2E1-mediated reactions (Drug Metab Rev 2011) has been refined with the introduction of ideas of Trigger-residue and the residue-initiated movement of ligands in the active site. The refined system also includes ideas of bi-molecule binding and angled-placement, which allow to sit diverse types of ligands on Template. With the use of these ideas in common with other Template systems for human CYP1A1, CYP1A2 and CYP3A4 (Drug Metab Pharmacokinet 2016, 2017, 2019, and 2020), 349 reactions of 192 distinct chemicals published as CYP2E1 ligands were examined in the refined system. Verifications of good and poor substrates, regioselectivity and also inhibitory interaction were available faithfully for these ligands from their placements on the refined Template and rules for interaction modes, accompanied with their deciphering information to lead to the judgements. The refined CYP2E1 Template system will thus offer more reliable estimations of human CYP2E1 catalysis toward ligands of diverse structures.
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Affiliation(s)
- Yasushi Yamazoe
- Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, 980-8578, Japan; Division of Risk Assessment, National Institute of Health Sciences, Tonomachi 3-25-26, Kawasaki-ku, Kanagawa, 210-9501, Japan.
| | - Norie Murayama
- Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan
| | - Kouichi Yoshinari
- Laboratory of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
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Deisenroth C, DeGroot DE, Zurlinden T, Eicher A, McCord J, Lee MY, Carmichael P, Thomas RS. The Alginate Immobilization of Metabolic Enzymes Platform Retrofits an Estrogen Receptor Transactivation Assay With Metabolic Competence. Toxicol Sci 2021; 178:281-301. [PMID: 32991717 DOI: 10.1093/toxsci/kfaa147] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The U.S. EPA Endocrine Disruptor Screening Program utilizes data across the ToxCast/Tox21 high-throughput screening (HTS) programs to evaluate the biological effects of potential endocrine active substances. A potential limitation to the use of in vitro assay data in regulatory decision-making is the lack of coverage for xenobiotic metabolic processes. Both hepatic- and peripheral-tissue metabolism can yield metabolites that exhibit greater activity than the parent compound (bioactivation) or are inactive (bioinactivation) for a given biological target. Interpretation of biological effect data for both putative endocrine active substances, as well as other chemicals, screened in HTS assays may benefit from the addition of xenobiotic metabolic capabilities to decrease the uncertainty in predicting potential hazards to human health. The objective of this study was to develop an approach to retrofit existing HTS assays with hepatic metabolism. The Alginate Immobilization of Metabolic Enzymes (AIME) platform encapsulates hepatic S9 fractions in alginate microspheres attached to 96-well peg lids. Functional characterization across a panel of reference substrates for phase I cytochrome P450 enzymes revealed substrate depletion with expected metabolite accumulation. Performance of the AIME method in the VM7Luc estrogen receptor transactivation assay was evaluated across 15 reference chemicals and 48 test chemicals that yield metabolites previously identified as estrogen receptor active or inactive. The results demonstrate the utility of applying the AIME method for identification of false-positive and false-negative target assay effects, reprioritization of hazard based on metabolism-dependent bioactivity, and enhanced in vivo concordance with the rodent uterotrophic bioassay. Integration of the AIME metabolism method may prove useful for future biochemical and cell-based HTS applications.
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Affiliation(s)
- Chad Deisenroth
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Danica E DeGroot
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Todd Zurlinden
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Andrew Eicher
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - James McCord
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Mi-Young Lee
- Safety and Environmental Assurance Centre, Unilever, Colworth Science, Park, Bedford, Sharnbrook MK44 1LQ, UK
| | - Paul Carmichael
- Safety and Environmental Assurance Centre, Unilever, Colworth Science, Park, Bedford, Sharnbrook MK44 1LQ, UK
| | - Russell S Thomas
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
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5
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Ozawa S, Miura T, Terashima J, Habano W, Ishida S. Recent Progress in Prediction Systems for Drug-induced Liver Injury Using in vitro Cell Culture. Drug Metab Lett 2020; 14:25-40. [PMID: 33267768 DOI: 10.2174/1872312814666201202112610] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/26/2020] [Accepted: 11/03/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND In order to avoid drug-induced liver injury (DILI), in vitro assays, which enable the assessment of both metabolic activation and immune reaction processes that ultimately result in DILI, are needed. OBJECTIVE In this study, the recent progress in the application of in vitro assays using cell culture systems is reviewed for potential DILI-causing drugs/xenobiotics and a mechanistic study on DILI, as well as for the limitations of in vitro cell culture systems for DILI research. METHODS Information related to DILI was collected through a literature search of the PubMed database. RESULTS The initial biological event for the onset of DILI is the formation of cellular protein adducts after drugs have been metabolically activated by drug metabolizing enzymes. The damaged peptides derived from protein adducts lead to the activation of CD4+ helper T lymphocytes and recognition by CD8+ cytotoxic T lymphocytes, which destroy hepatocytes through immunological reactions. Because DILI is a major cause of drug attrition and drug withdrawal, numerous in vitro systems consisting of hepatocytes and immune/inflammatory cells, or spheroids of human primary hepatocytes containing non-parenchymal cells have been developed. These cellular-based systems have identified DILIinducing drugs with approximately 50% sensitivity and 90% specificity. CONCLUSION Different co-culture systems consisting of human hepatocyte-derived cells and other immune/inflammatory cells have enabled the identification of DILI-causing drugs and of the actual mechanisms of action.
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Affiliation(s)
- Shogo Ozawa
- Department of Clinical Pharmaceutical Sciences, Division of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Yahaba. Japan
| | - Toshitaka Miura
- Department of Clinical Pharmaceutical Sciences, Division of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Yahaba. Japan
| | - Jun Terashima
- Department of Clinical Pharmaceutical Sciences, Division of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Yahaba. Japan
| | - Wataru Habano
- Department of Clinical Pharmaceutical Sciences, Division of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Yahaba. Japan
| | - Seiichi Ishida
- Department of Pharmacology, National Institute of Health Sciences, Kawasaki. Japan
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Travelli C, Aprile S, Mattoteia D, Colombo G, Clemente N, Scanziani E, Terrazzino S, Alisi MA, Polenzani L, Grosa G, Genazzani AA, Tron GC, Galli U. Identification of potent triazolylpyridine nicotinamide phosphoribosyltransferase (NAMPT) inhibitors bearing a 1,2,3-triazole tail group. Eur J Med Chem 2019; 181:111576. [PMID: 31400709 DOI: 10.1016/j.ejmech.2019.111576] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 12/14/2022]
Abstract
The enzyme nicotinamide phosphoribosyltransferase is both a key intracellular enzyme for NAD biosynthesis (iNAMPT) and an extracellular cytokine (eNAMPT). The relationship between this latter role and the catalytic activity of the enzyme is at present unknown. With the intent of discovering inhibitors specifically able to target eNAMPT, we increased the polarity of MV78 (EC50 = 5.8 nM; IC50 = 3.1 nM), a NAMPT inhibitor previously discovered by us. The replacement of a phenyl ring with a 1,2,3-triazole bearing a protonable N,N-dialkyl methanamine group gave a series of molecules which maintained the inhibition of the enzymatic activity but were unable to cross the plasma membrane and affect cell viability in vitro. Compounds 30b and 30f can therefore be considered as the first experimental/pharmacological tools for scientists that wish to understand the role of the catalytic activity of eNAMPT. Serendipitously, we also discovered a compound (25) which, notwithstanding its high polarity, was able to cross the plasma membrane being cytotoxic, a potent NAMPT inhibitor and effective in reducing growth of triple negative mammary carcinoma in mice. In our hands, 25 lacked retinal and cardiac toxicity, although we observed a lesser toxicity of NAMPT inhibitors in general compared to other reports.
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Affiliation(s)
- Cristina Travelli
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy; Dipartimento di Scienze del Farmaco, Università degli Studi di Pavia, Viale Taramelli 12, 27100, Pavia, Italy
| | - Silvio Aprile
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy
| | - Daiana Mattoteia
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy
| | - Giorgia Colombo
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy
| | - Nausicaa Clemente
- Dipartimento di Scienze della Salute and IRCAD, Università degli Studi del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
| | - Eugenio Scanziani
- Dipartimento di Medicina Veterinaria, Università degli Studi di Milano, Via Celoria 10, 20133, Milano, Italy; Mouse and Animal Pathology Lab (MAPLab), Fondazione Università degli Studi di Milano, Viale Ortles 22/4, 20139, Milano, Italy
| | - Salvatore Terrazzino
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy
| | - Maria Alessandra Alisi
- Angelini RR&D (Research, Regulatory & Development), Angelini S.p.A, Piazzale della Stazione Snc, 00071, S. Palomba, Roma, Italy
| | - Lorenzo Polenzani
- Angelini RR&D (Research, Regulatory & Development), Angelini S.p.A, Piazzale della Stazione Snc, 00071, S. Palomba, Roma, Italy
| | - Giorgio Grosa
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy
| | - Armando A Genazzani
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy
| | - Gian Cesare Tron
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy
| | - Ubaldina Galli
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2, 28100, Novara, Italy.
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7
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Ford KA, Ryslik G, Sodhi J, Halladay J, Diaz D, Dambach D, Masuda M. Computational predictions of the site of metabolism of cytochrome P450 2D6 substrates: comparative analysis, molecular docking, bioactivation and toxicological implications. Drug Metab Rev 2015; 47:291-319. [DOI: 10.3109/03602532.2015.1047026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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8
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Hsiao YW, Petersson C, Svensson MA, Norinder U. A Pragmatic Approach Using First-Principle Methods to Address Site of Metabolism with Implications for Reactive Metabolite Formation. J Chem Inf Model 2012; 52:686-95. [DOI: 10.1021/ci200523f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Ya-Wen Hsiao
- AstraZeneca Research and Development Södertälje, SE-151 85
Södertälje, Sweden
| | - Carl Petersson
- AstraZeneca Research and Development Södertälje, SE-151 85
Södertälje, Sweden
| | - Mats A. Svensson
- AstraZeneca Research and Development Södertälje, SE-151 85
Södertälje, Sweden
| | - Ulf Norinder
- AstraZeneca Research and Development Södertälje, SE-151 85
Södertälje, Sweden
- Department of Pharmacy, Uppsala University, SE-751 23 Uppsala, Sweden
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9
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Kikura-Hanajiri R, Kawamura M, Miyajima A, Sunouchi M, Goda Y. Chiral analyses of dextromethorphan/levomethorphan and their metabolites in rat and human samples using LC-MS/MS. Anal Bioanal Chem 2011; 400:165-74. [PMID: 21311876 DOI: 10.1007/s00216-011-4707-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 01/07/2011] [Accepted: 01/22/2011] [Indexed: 01/10/2023]
Abstract
In order to develop an analytical method for the discrimination of dextromethorphan (an antitussive medicine) from its enantiomer, levomethorphan (a narcotic) in biological samples, chiral analyses of these drugs and their O-demethyl and/or N-demethyl metabolites in rat plasma, urine, and hair were carried out using LC-MS/MS. After the i.p. administration of dextromethorphan or levomethorphan to pigmented hairy male DA rats (5 mg/kg/day, 10 days), the parent compounds and their three metabolites in plasma, urine and hair were determined using LC-MS/MS. Complete chiral separation was achieved in 12 min on a Chiral CD-Ph column in 0.1% formic acid-acetonitrile by a linear gradient program. Most of the metabolites were detected as being the corresponding O-demethyl and N, O-didemethyl metabolites in the rat plasma and urine after the hydrolysis of O-glucuronides, although obvious differences in the amounts of these metabolites were found between the dextro and levo forms. No racemation was observed through O- and/or N-demethylation. In the rat hair samples collected 4 weeks after the first administration, those differences were more clearly detected and the concentrations of the parent compounds, their O-demethyl, N-demethyl, and N, O-didemethyl metabolites were 63.4, 2.7, 25.1, and 0.7 ng/mg for the dextro forms and 24.5, 24.6, 2.6, and 0.5 ng/mg for the levo forms, respectively. In order to fully investigate the differences of their metabolic properties between dextromethorphan and levomethorphan, DA rat and human liver microsomes were studied. The results suggested that there might be an enantioselective metabolism of levomethorphan, especially with regard to the O-demethylation, not only in DA rat but human liver microsomes as well. The proposed chiral analyses might be applied to human samples and could be useful for discriminating dextromethorphan use from levomethorphan use in the field of forensic toxicology, although further studies should be carried out using authentic human samples.
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Affiliation(s)
- Ruri Kikura-Hanajiri
- Division of Pharmacognosy, Phytochemistry and Narcotics, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya, Tokyo 158-8501, Japan.
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10
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Chan K, Lehmler HJ, Sivagnanam M, Feng CY, Robertson L, O'Brien PJ. Cytotoxic effects of polychlorinated biphenyl hydroquinone metabolites in rat hepatocytes. J Appl Toxicol 2010; 30:163-71. [PMID: 19830680 DOI: 10.1002/jat.1483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants that exhibit various toxic effects in animals and exposed human populations. The molecular mechanisms of PCB toxicity have been attributed to the toxicological properties of its metabolites, such as hydroquinones, formed by cytochrome-P-450 oxidation. The effects of PCB hydroquinone metabolites towards freshly isolated rat hepatocytes were investigated. Hydroquinones can be oxidized to semiquinones and/or quinone metabolites. These metabolites can conjugate glutathione or can oxidize glutathione as a result of redox cycling. This depletes hepatocyte glutathione, which can inhibit cellular defence mechanisms, causing cell death and an increased susceptibility to oxidative stress. However in the following, glutathione-depleted hepatocytes became more resistant to the hydroquinone metabolites of PCBs. This suggested that their glutathione conjugates were toxic and that there was a third type of quinone toxicity mechanism which involved a hydrogen peroxide-accelerated autoxidation of the hydroquinones to form toxic electrophilic quinone and semiquinone-glutathione conjugates.
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Affiliation(s)
- Katie Chan
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, 144 College St., Toronto, ON, Canada M5S 3M2
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11
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Rydberg P, Vasanthanathan P, Oostenbrink C, Olsen L. Fast prediction of cytochrome P450 mediated drug metabolism. ChemMedChem 2010; 4:2070-9. [PMID: 19852016 DOI: 10.1002/cmdc.200900363] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cytochrome P450 mediated metabolism of drugs is one of the major determinants of their kinetic profile, and prediction of this metabolism is therefore highly relevant during the drug discovery and development process. A new rule-based method, based on results from density functional theory calculations, for predicting activation energies for aliphatic and aromatic oxidations by cytochromes P450 is developed and compared with several other methods. Although the applicability of the method is currently limited to a subset of P450 reactions, these reactions describe more than 90 % of the metabolites. The rules employed are relatively few and general, and when combined with solvent-accessible surface area calculations to account for steric accessibility, the method gives a major P450 metabolite as first-ranked position for 75 % of the substrates, and ranked in the top three for 90 % of substrates for a set of 20 substrates. In combination with docking, it can predict isoform-specific metabolism, and we apply this on CYP1A2 with very good results on 81 substrates, for which we find a major metabolite ranked in the top three for 90 % of the substrates (100 % in the training set and 87 % in the larger test set).
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Affiliation(s)
- Patrik Rydberg
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
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12
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Jason TLH, Koropatnick J, Berg RW. Toxicology of antisense therapeutics. Toxicol Appl Pharmacol 2004; 201:66-83. [PMID: 15519609 DOI: 10.1016/j.taap.2004.04.017] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2003] [Accepted: 04/28/2004] [Indexed: 12/24/2022]
Abstract
Targeting unique mRNA molecules using antisense approaches, based on sequence specificity of double-stranded nucleic acid interactions should, in theory, allow for design of drugs with high specificity for intended targets. Antisense-induced degradation or inhibition of translation of a target mRNA is potentially capable of inhibiting the expression of any target protein. In fact, a large number of proteins of widely varied character have been successfully downregulated using an assortment of antisense-based approaches. The most prevalent approach has been to use antisense oligonucleotides (ASOs), which have progressed through the preclinical development stages including pharmacokinetics and toxicological studies. A small number of ASOs are currently in human clinical trials. These trials have highlighted several toxicities that are attributable to the chemical structure of the ASOs, and not to the particular ASO or target mRNA sequence. These include mild thrombocytopenia and hyperglycemia, activation of the complement and coagulation cascades, and hypotension. Dose-limiting toxicities have been related to hepatocellular degeneration leading to decreased levels of albumin and cholesterol. Despite these toxicities, which are generally mild and readily treatable with available standard medications, the clinical trials have clearly shown that ASOs can be safely administered to patients. Alternative chemistries of ASOs are also being pursued by many investigators to improve specificity and antisense efficacy and to reduce toxicity. In the design of ASOs for anticancer therapeutics in particular, the goal is often to enhance the cytotoxicity of traditional drugs toward cancer cells or to reduce the toxicity to normal cells to improve the therapeutic index of existing clinically relevant cancer chemotherapy drugs. We predict that use of antisense ASOs in combination with small molecule therapeutics against the target protein encoded by the antisense-targeted mRNA, or an alternate target in the same or a connected biological pathway, will likely be the most beneficial application of this emerging class of therapeutic agent.
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Affiliation(s)
- Tracey L H Jason
- Cancer Research Laboratories, London Regional Cancer Centre, London, Ontario, Canada N6A 4L6
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Combes RD. The case for taking account of metabolism when testing for potential endocrine disruptors in vitro. Altern Lab Anim 2004; 32:121-35. [PMID: 15601241 DOI: 10.1177/026119290403200210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Legislation in the USA, Europe and Japan will require that chemicals are tested for their ability to disrupt the hormonal systems of mammals. Such chemicals are known as endocrine disruptors (EDs), and will require extensive testing as part of the new European Union Registration, Evaluation and Authorisation of Chemicals (REACH) system for the risk assessment of chemicals. Both in vivo and in vitro tests are proposed for this purpose, and there has been much discussion and action concerning the development and validation of such tests. However, to date, little interest has been shown in incorporating metabolism into in vitro tests for EDs, in sharp contrast to other areas of toxicity testing, such as genotoxicity, and, ironically, such in vitro tests are criticised for not modelling in vivo metabolism. This is despite the existence of much information showing that endogenous and exogenous steroids are extensively metabolised by Phase I and Phase II enzymes both in the liver and in hormonally active tissues. Such metabolism can lead to the activation or detoxification of steroids and EDs. The absence of metabolism from these tests could give rise to false-positive data (due to lack of detoxification) or false-negative data (lack of activation). This paper aims to explain why in vitro assays for EDs should incorporate mammalian metabolising systems. The background to ED testing, the test methods available, and the role of mammalian metabolism in the activation and detoxification of both endogenous and exogenous steroids, are described. The available types of metabolising systems are compared, and the potential problems in incorporating metabolising systems into in vitro tests for EDs, and how these might be overcome, are discussed. It is recommended that there should be: a) an assessment of the intrinsic metabolising capacity of cell systems used in tests for EDs; b) an investigation into the relevance of using the prostaglandin H synthase system for metabolising EDs; and c) a feasibility study into the generation of genetically engineered mammalian cell lines expressing specific metabolising enzymes, which could also be used to detect EDs.
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Affiliation(s)
- Robert D Combes
- FRAME, Russell & Burch House, 96-98 North Sherwood Street, Nottingham NG1 4EE, UK.
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Kitamura S, Sanoh S, Kohta R, Suzuki T, Sugihara K, Fujimoto N, Ohta S. Metabolic Activation of Proestrogenic Diphenyl and Related Compounds by Rat Liver Microsomes. ACTA ACUST UNITED AC 2003. [DOI: 10.1248/jhs.49.298] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Seigo Sanoh
- Graduate School of Biomedical Sciences, Hiroshima University
| | - Ryuki Kohta
- Graduate School of Biomedical Sciences, Hiroshima University
| | - Tomoharu Suzuki
- Graduate School of Biomedical Sciences, Hiroshima University
| | - Kazumi Sugihara
- Graduate School of Biomedical Sciences, Hiroshima University
| | - Nariaki Fujimoto
- Research Institute for Radiation Biology and Medicine, Hiroshima University
| | - Shigeru Ohta
- Graduate School of Biomedical Sciences, Hiroshima University
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Chapter 7: Biokinetics. Altern Lab Anim 2002. [DOI: 10.1177/026119290203001s07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
This chapter is an update of the data on substrates, reactions, inducers, and inhibitors of human CYP enzymes published previously by Rendic and DiCarlo (1), now covering selection of the literature through 2001 in the reference section. The data are presented in a tabular form (Table 1) to provide a framework for predicting and interpreting the new P450 metabolic data. The data are formatted in an Excel format as most suitable for off-line searching and management of the Web-database. The data are presented as stated by the author(s) and in the case when several references are cited the data are presented according to the latest published information. The searchable database is available either as an Excel file (for information contact the author), or as a Web-searchable database (Human P450 Metabolism Database, www.gentest.com) enabling the readers easy and quick approach to the latest updates on human CYP metabolic reactions.
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Affiliation(s)
- Slobodan Rendic
- Faculty of Pharmacy and Biochemistry, University of Zagreb, Croatia.
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