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Cronin MTD, Bauer FJ, Bonnell M, Campos B, Ebbrell DJ, Firman JW, Gutsell S, Hodges G, Patlewicz G, Sapounidou M, Spînu N, Thomas PC, Worth AP. A scheme to evaluate structural alerts to predict toxicity - Assessing confidence by characterising uncertainties. Regul Toxicol Pharmacol 2022; 135:105249. [PMID: 36041585 PMCID: PMC9585125 DOI: 10.1016/j.yrtph.2022.105249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 07/12/2022] [Accepted: 08/17/2022] [Indexed: 11/26/2022]
Abstract
Structure-activity relationships (SARs) in toxicology have enabled the formation of structural rules which, when coded as structural alerts, are essential tools in in silico toxicology. Whilst other in silico methods have approaches for their evaluation, there is no formal process to assess the confidence that may be associated with a structural alert. This investigation proposes twelve criteria to assess the uncertainty associated with structural alerts, allowing for an assessment of confidence. The criteria are based around the stated purpose, description of the chemistry, toxicology and mechanism, performance and coverage, as well as corroborating and supporting evidence of the alert. Alerts can be given a confidence assessment and score, enabling the identification of areas where more information may be beneficial. The scheme to evaluate structural alerts was placed in the context of various use cases for industrial and regulatory applications. The analysis of alerts, and consideration of the evaluation scheme, identifies the different characteristics an alert may have, such as being highly specific or generic. These characteristics may determine when an alert can be used for specific uses such as identification of analogues for read-across or hazard identification. Structural alerts are useful tools for predictive toxicology. 12 criteria to evaluate structural alerts have been identified. A strategy to determine confidence of structural alerts is presented. Different use cases require different characteristics of structural alerts. A Scheme to Evaluate Structural Alerts to Predict Toxicity – Assessing Confidence By Characterising Uncertainties.
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Affiliation(s)
- Mark T D Cronin
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Franklin J Bauer
- KREATiS SAS, 23 rue du Creuzat, ZAC de St-Hubert, 38080, L'Isle d'Abeau, France
| | - Mark Bonnell
- Science and Risk Assessment Directorate, Environment & Climate Change Canada, 351 St. Joseph Blvd, Gatineau, Quebec, K1A 0H3, Canada
| | - Bruno Campos
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Bedfordshire, MK44 1LQ, UK
| | - David J Ebbrell
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - James W Firman
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Steve Gutsell
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Bedfordshire, MK44 1LQ, UK
| | - Geoff Hodges
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Bedfordshire, MK44 1LQ, UK
| | - Grace Patlewicz
- Center for Computational Toxicology and Exposure (CCTE), US Environmental Protection Agency, 109 TW Alexander Dr, RTP, NC, 27709, USA
| | - Maria Sapounidou
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Nicoleta Spînu
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Paul C Thomas
- KREATiS SAS, 23 rue du Creuzat, ZAC de St-Hubert, 38080, L'Isle d'Abeau, France
| | - Andrew P Worth
- European Commission, Joint Research Centre (JRC), Ispra, Italy.
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2
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Modes of action considerations in threshold expectations for health effects of benzene. Toxicol Lett 2020; 334:78-86. [DOI: 10.1016/j.toxlet.2020.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 09/05/2020] [Accepted: 09/10/2020] [Indexed: 01/21/2023]
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3
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Schnatter AR, Rooseboom M, Kocabas NA, North CM, Dalzell A, Twisk J, Faulhammer F, Rushton E, Boogaard PJ, Ostapenkaite V, Williams SD. Derivation of an occupational exposure limit for benzene using epidemiological study quality assessment tools. Toxicol Lett 2020; 334:117-144. [PMID: 32497562 DOI: 10.1016/j.toxlet.2020.05.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/20/2020] [Accepted: 05/28/2020] [Indexed: 02/04/2023]
Abstract
This paper derives an occupational exposure limit for benzene using quality assessed data. Seventy-seven genotoxicity and 36 haematotoxicity studies in workers were scored for study quality with an adapted tool based on that of Vlaanderen et al., 2008 (Environ Health. Perspect. 116 1700-5). These endpoints were selected as they are the most sensitive and relevant to the proposed mode of action (MOA) and protecting against these will protect against benzene carcinogenicity. Lowest and No- Adverse Effect Concentrations (LOAECs and NOAECs) were derived from the highest quality studies (i.e. those ranked in the top tertile or top half) and further assessed as being "more certain" or "less certain". Several sensitivity analyses were conducted to assess whether alternative "high quality" constructs affected conclusions. The lowest haematotoxicity LOAECs showed effects near 2 ppm (8 h TWA), and no effects at 0.59 ppm. For genotoxicity, studies also showed effects near 2 ppm and showed no effects at about 0.69 ppm. Several sensitivity analyses supported these observations. These data define a benzene LOAEC of 2 ppm (8 h TWA) and a NOAEC of 0.5 ppm (8 h TWA). Allowing for possible subclinical effects in bone marrow not apparent in studies of peripheral blood endpoints, an OEL of 0.25 ppm (8 h TWA) is proposed.
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Affiliation(s)
| | | | | | - Colin M North
- ExxonMobil Biomedical Sciences, Inc, Annandale, NJ, USA
| | | | - Johannes Twisk
- Dow Chemical International Pvt. Ltd, Terneuzen, the Netherlands
| | | | - Erik Rushton
- Basell Service Company B.V., Rotterdam, the Netherlands
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4
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Djordjevic I, Wicaksono G, Solic I, Steele TWJ. In Vitro Biocompatibility of Diazirine‐Grafted Biomaterials. Macromol Rapid Commun 2020; 41:e2000235. [DOI: 10.1002/marc.202000235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/24/2020] [Indexed: 12/25/2022]
Affiliation(s)
- Ivan Djordjevic
- School of Materials Science and Engineering (MSE) Nanyang Technological University (NTU) Singapore 639798 Singapore
| | - Gautama Wicaksono
- School of Materials Science and Engineering (MSE) Nanyang Technological University (NTU) Singapore 639798 Singapore
| | - Ivan Solic
- School of Materials Science and Engineering (MSE) Nanyang Technological University (NTU) Singapore 639798 Singapore
| | - Terry W. J. Steele
- School of Materials Science and Engineering (MSE) Nanyang Technological University (NTU) Singapore 639798 Singapore
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5
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Samuelsen JT, Michelsen VB, Bruun JA, Dahl JE, Jensen E, Örtengren U. The dental monomer HEMA causes proteome changes in human THP-1 monocytes. J Biomed Mater Res A 2019; 107:851-859. [DOI: 10.1002/jbm.a.36601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/16/2018] [Accepted: 12/26/2018] [Indexed: 12/15/2022]
Affiliation(s)
| | | | - Jack-Ansgar Bruun
- Department of Medical Biology, Faculty of Health Sciences; University of Tromsø; Tromsø Norway
| | - Jon E. Dahl
- Nordic Institute of Dental Materials (NIOM); Oslo Norway
| | - Einar Jensen
- Department of Pharmacy, Faculty of Health Sciences; University of Tromsø; Tromsø Norway
| | - Ulf Örtengren
- Department of Clinical Dentistry, Faculty of Health Sciences; University of Tromsø; Tromsø Norway
- Department of Cariology; Institute for Odontology, Sahlgrenska Academy, Göteborg University; Göteborg Sweden
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6
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Gabbert S, Leontaridou M, Landsiedel R. A Critical Review of Adverse Outcome Pathway-Based Concepts and Tools for Integrating Information from Nonanimal Testing Methods: The Case of Skin Sensitization. ACTA ACUST UNITED AC 2017. [DOI: 10.1089/aivt.2017.0015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Silke Gabbert
- Environmental Economics and Natural Resources Group, Wageningen University, Wageningen, The Netherlands
| | - Maria Leontaridou
- Environmental Economics and Natural Resources Group, Wageningen University, Wageningen, The Netherlands
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7
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Böhme A, Laqua A, Schüürmann G. Chemoavailability of Organic Electrophiles: Impact of Hydrophobicity and Reactivity on Their Aquatic Excess Toxicity. Chem Res Toxicol 2016; 29:952-62. [DOI: 10.1021/acs.chemrestox.5b00398] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Alexander Böhme
- UFZ
Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany
| | - Anja Laqua
- UFZ
Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany
- Institute
for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Str. 29, 09596 Freiberg, Germany
| | - Gerrit Schüürmann
- UFZ
Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany
- Institute
for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Str. 29, 09596 Freiberg, Germany
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Patlewicz G, Ball N, Boogaard P, Becker R, Hubesch B. Building scientific confidence in the development and evaluation of read-across. Regul Toxicol Pharmacol 2015; 72:117-33. [DOI: 10.1016/j.yrtph.2015.03.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 02/08/2023]
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Towards AOP application--implementation of an integrated approach to testing and assessment (IATA) into a pipeline tool for skin sensitization. Regul Toxicol Pharmacol 2014; 69:529-45. [PMID: 24928565 DOI: 10.1016/j.yrtph.2014.06.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 05/27/2014] [Accepted: 06/01/2014] [Indexed: 12/13/2022]
Abstract
Since the OECD published the Adverse Outcome Pathway (AOP) for skin sensitization, many efforts have focused on how to integrate and interpret nonstandard information generated for key events in a manner that can be practically useful for decision making. These types of frameworks are known as Integrated Approaches to Testing and Assessment (IATA). Here we have outlined an IATA for skin sensitization which focuses on existing information including non testing approaches such as QSAR and read-across. The IATA was implemented into a pipeline tool using OASIS technology to provide a means of systematically collating and compiling relevant information which could be used in an assessment of skin sensitization potential. A test set of 100 substances with available skin sensitization information was profiled using the pipeline IATA. In silico and in chemico profiling information alone was able to correctly predict skin sensitization potential, with a preliminary accuracy of 73.85%. Information from other relevant endpoints (e.g., Ames mutagenicity) was found to improve the accuracy (to 87.6%) when coupled with a reaction chemistry mechanistic understanding. This pipeline platform could be useful in the assessment of skin sensitization potential and marks a step change in how non testing approaches can be practically applied.
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Rorije E, Aldenberg T, Buist H, Kroese D, Schüürmann G. The OSIRIS Weight of Evidence approach: ITS for skin sensitisation. Regul Toxicol Pharmacol 2013; 67:146-56. [DOI: 10.1016/j.yrtph.2013.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 06/11/2013] [Accepted: 06/12/2013] [Indexed: 01/24/2023]
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11
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Patlewicz G, Ball N, Booth ED, Hulzebos E, Zvinavashe E, Hennes C. Use of category approaches, read-across and (Q)SAR: General considerations. Regul Toxicol Pharmacol 2013; 67:1-12. [DOI: 10.1016/j.yrtph.2013.06.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/25/2013] [Accepted: 06/03/2013] [Indexed: 10/26/2022]
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12
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Nendza M, Gabbert S, Kühne R, Lombardo A, Roncaglioni A, Benfenati E, Benigni R, Bossa C, Strempel S, Scheringer M, Fernández A, Rallo R, Giralt F, Dimitrov S, Mekenyan O, Bringezu F, Schüürmann G. A comparative survey of chemistry-driven in silico methods to identify hazardous substances under REACH. Regul Toxicol Pharmacol 2013; 66:301-14. [DOI: 10.1016/j.yrtph.2013.05.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 05/09/2013] [Accepted: 05/11/2013] [Indexed: 11/29/2022]
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13
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Péry ARR, Schüürmann G, Ciffroy P, Faust M, Backhaus T, Aicher L, Mombelli E, Tebby C, Cronin MTD, Tissot S, Andres S, Brignon JM, Frewer L, Georgiou S, Mattas K, Vergnaud JC, Peijnenburg W, Capri E, Marchis A, Wilks MF. Perspectives for integrating human and environmental risk assessment and synergies with socio-economic analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 456-457:307-316. [PMID: 23624004 DOI: 10.1016/j.scitotenv.2013.03.099] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 03/29/2013] [Accepted: 03/29/2013] [Indexed: 06/02/2023]
Abstract
For more than a decade, the integration of human and environmental risk assessment (RA) has become an attractive vision. At the same time, existing European regulations of chemical substances such as REACH (EC Regulation No. 1907/2006), the Plant Protection Products Regulation (EC regulation 1107/2009) and Biocide Regulation (EC Regulation 528/2012) continue to ask for sector-specific RAs, each of which have their individual information requirements regarding exposure and hazard data, and also use different methodologies for the ultimate risk quantification. In response to this difference between the vision for integration and the current scientific and regulatory practice, the present paper outlines five medium-term opportunities for integrating human and environmental RA, followed by detailed discussions of the associated major components and their state of the art. Current hazard assessment approaches are analyzed in terms of data availability and quality, and covering non-test tools, the integrated testing strategy (ITS) approach, the adverse outcome pathway (AOP) concept, methods for assessing uncertainty, and the issue of explicitly treating mixture toxicity. With respect to exposure, opportunities for integrating exposure assessment are discussed, taking into account the uncertainty, standardization and validation of exposure modeling as well as the availability of exposure data. A further focus is on ways to complement RA by a socio-economic assessment (SEA) in order to better inform about risk management options. In this way, the present analysis, developed as part of the EU FP7 project HEROIC, may contribute to paving the way for integrating, where useful and possible, human and environmental RA in a manner suitable for its coupling with SEA.
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Affiliation(s)
- A R R Péry
- INERIS, Parc Alata, BP2, 60550 Verneuil-en-Halatte, France.
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14
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Thaens D, Heinzelmann D, Böhme A, Paschke A, Schüürmann G. Chemoassay screening of DNA-reactive mutagenicity with 4-(4-nitrobenzyl)pyridine - application to epoxides, oxetanes, and sulfur heterocycles. Chem Res Toxicol 2012; 25:2092-102. [PMID: 22889134 DOI: 10.1021/tx3001412] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Organic electrophiles have the potential to covalently attack DNA bases, and thus initiate mutagenic and carcinogenic processes. In this context, aromatic nitrogen sites of the DNA bases are often particularly nucleophilic, with guanine N7 being one of the most favored sites of adduct formation with electrophilic xenobiotics. Employing 4-(4-nitrobenzyl)pyridine (NBP) as model nucleophile with a respective aromatic ═N- unit, a new kinetic variant of a photometric chemoassay for sensing the DNA reactivity of organic compounds is introduced and applied to 21 three- and four-membered oxygen and sulfur heterocycles (15 epoxides, two thiiranes, three oxetanes, and one thietane). Besides six unreactive compounds (oxetanes, thietane, and aliphatic epoxides with six or more side-chain carbons), second-order rate constants of the electrophile-NBP reaction, k(NBP), were obtained for 15 compounds, ranging from (1.16 ± 0.05)·10⁻³ to (36.5 ± 0.6)·10⁻³ L mol⁻¹ min⁻¹ in a methanol/tris-HCl buffer (16/84 v/v) reaction medium. Solvolysis as confounding factor was addressed by determining respective first-order rate constants k(solv). Analysis of the k(NBP) values resulted in structure-reactivity relationships, and comparison with literature data from the Ames test bacterial strains TA100, TA1535, and TA97 (Salmonella typhimurium) as well as from WP2 uvrA (Escherichia coli) revealed significant log-log relationships between the mutagenic potency of the heterocycles and their reactivity toward NBP. The latter demonstrates the potential of the NBP chemoassay as a nonanimal component of integrated testing strategies for REACH, enabling an efficient screening of organic electrophiles with respect to their DNA reactivity and associated mutagenicity and carcinogenicity.
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Affiliation(s)
- Diana Thaens
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstraße 15, 04318 Leipzig, Germany
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15
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Inroads to predict in vivo toxicology-an introduction to the eTOX Project. Int J Mol Sci 2012; 13:3820-3846. [PMID: 22489185 PMCID: PMC3317745 DOI: 10.3390/ijms13033820] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/30/2012] [Accepted: 03/14/2012] [Indexed: 12/20/2022] Open
Abstract
There is a widespread awareness that the wealth of preclinical toxicity data that the pharmaceutical industry has generated in recent decades is not exploited as efficiently as it could be. Enhanced data availability for compound comparison (“read-across”), or for data mining to build predictive tools, should lead to a more efficient drug development process and contribute to the reduction of animal use (3Rs principle). In order to achieve these goals, a consortium approach, grouping numbers of relevant partners, is required. The eTOX (“electronic toxicity”) consortium represents such a project and is a public-private partnership within the framework of the European Innovative Medicines Initiative (IMI). The project aims at the development of in silico prediction systems for organ and in vivo toxicity. The backbone of the project will be a database consisting of preclinical toxicity data for drug compounds or candidates extracted from previously unpublished, legacy reports from thirteen European and European operation-based pharmaceutical companies. The database will be enhanced by incorporation of publically available, high quality toxicology data. Seven academic institutes and five small-to-medium size enterprises (SMEs) contribute with their expertise in data gathering, database curation, data mining, chemoinformatics and predictive systems development. The outcome of the project will be a predictive system contributing to early potential hazard identification and risk assessment during the drug development process. The concept and strategy of the eTOX project is described here, together with current achievements and future deliverables.
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16
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Mekenyan OG, Petkov PI, Kotov SV, Stoeva S, Kamenska VB, Dimitrov SD, Honma M, Hayashi M, Benigni R, Donner EM, Patlewicz G. Investigating the Relationship between in Vitro–in Vivo Genotoxicity: Derivation of Mechanistic QSAR Models for in Vivo Liver Genotoxicity and in Vivo Bone Marrow Micronucleus Formation Which Encompass Metabolism. Chem Res Toxicol 2012; 25:277-96. [DOI: 10.1021/tx200547s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ovanes G. Mekenyan
- Laboratory of Mathematical Chemistry (LMC), As. Zlatarov University, Bourgas, Bulgaria
| | - Petko I. Petkov
- Laboratory of Mathematical Chemistry (LMC), As. Zlatarov University, Bourgas, Bulgaria
| | - Stefan V. Kotov
- Laboratory of Mathematical Chemistry (LMC), As. Zlatarov University, Bourgas, Bulgaria
| | - Stoyanka Stoeva
- Laboratory of Mathematical Chemistry (LMC), As. Zlatarov University, Bourgas, Bulgaria
| | - Verginia B. Kamenska
- Laboratory of Mathematical Chemistry (LMC), As. Zlatarov University, Bourgas, Bulgaria
| | - Sabcho D. Dimitrov
- Laboratory of Mathematical Chemistry (LMC), As. Zlatarov University, Bourgas, Bulgaria
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Tokyo, Japan
| | - Makoto Hayashi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Tokyo, Japan
- Biosafety Research Center, Foods, Drugs and Pesticides, Iwata, Japan
| | - Romualdo Benigni
- Environment and Health Department, Istituto Superiore di Sanita', Rome, Italy
| | - E. Maria Donner
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark,
Delaware 19714-0050, United States
| | - Grace Patlewicz
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark,
Delaware 19714-0050, United States
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Mulliner D, Wondrousch D, Schüürmann G. Predicting Michael-acceptor reactivity and toxicity through quantum chemical transition-state calculations. Org Biomol Chem 2011; 9:8400-12. [DOI: 10.1039/c1ob06065a] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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18
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A potential in vitro epidermal equivalent assay to determine sensitizer potency. Toxicol In Vitro 2010; 25:347-57. [PMID: 20940038 DOI: 10.1016/j.tiv.2010.10.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 10/06/2010] [Accepted: 10/06/2010] [Indexed: 11/22/2022]
Abstract
Most in vitro assays aim to distinguish sensitizers from non-sensitizers. Few aim to classify sensitizers according to potency. Here, we describe a potential method for classifying sensitizers according to their irritant potency with the aid of in house epidermal equivalents (EE). Sixteen sensitizers were applied topically in a dose response to EE for 24h. The EE-EC(50) value (effective chemical concentration required to reduce cell viability by 50%) and the EE-IL-1α(10)(×) value (chemical concentration which increases IL-1α secretion by 10-fold) were calculated. From 16 sensitizers, EE-EC(50) and/or EE-IL-1α(10×) values were obtained from 12 skin sensitizers. EE-EC(50) and IL-1α(10×) values decreased in proportion to increasing sensitizer potency. The in vitro assay correlated with existing in vivo mouse and human sensitization data (LLNA, HRIPT), and showed low intra- and inter-experimental variability. Additionally DNCB and resorcinol were correctly assessed as extreme and moderate sensitizers using commercial EE (EST1000™ and RHE™). In conclusion, our data supports the view that irritancy may in part be a factor determining sensitizer potency. Since this assay does not distinguish sensitizers from non-sensitizers, its potential application is in a tiered strategy, where Tier 1 identifies sensitizers which may then tested in Tier 2, this assay, which determines sensitizer potency.
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