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Lee S, Ka Y, Lee B, Lee I, Seo YE, Shin H, Kho Y, Ji K. Single and mixture toxicity evaluation of avobenzone and homosalate to male zebrafish and H295R cells. CHEMOSPHERE 2023; 343:140271. [PMID: 37758070 DOI: 10.1016/j.chemosphere.2023.140271] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 09/22/2023] [Accepted: 09/23/2023] [Indexed: 10/02/2023]
Abstract
Avobenzone and homosalate are widely used in sunscreens to provide ultraviolet (UV) protection, either as single compounds or in combination. Some UV filters exhibit estrogenic or anti-androgenic activities, however, studies regarding their interactions and toxicity in mixtures are limited. In this study, the effect of the toxicity of a binary mixture comprising avobenzone (0.72 μg L-1) and homosalate (1.02 and 103 μg L-1) on steroid hormone biosynthesis were investigated using male zebrafish and human adrenocortical carcinoma (H295R) cells. In fish exposed to homosalate, a significant decrease in the gonadosomatic index, testosterone level, and transcription of several genes (e.g, hsd3b2, cyp17a1, and hsd17b1) and a significant increase in the hepatosomatic index, liver steatosis, 17β-estradiol level, and transcription of vtg gene were observed. These results suggest that estrogenic and anti-androgenic effects of homosalate were mediated by the steroidogenic pathway. The presence of 0.72 μg L-1 of avobenzone augmented the anti-androgenic responses in male fish. The testosterone level in the H295R cells were significantly decreased after they were exposed to homosalate alone or in combination with avobenzone, which is consistent with observations in male zebrafish. Further studies need to be conducted to understand the endocrine disrupting properties of long-term exposure to substances typically used in sunscreens.
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Affiliation(s)
- Sujin Lee
- Department of Environmental Health, Graduate School at Yongin University, Yongin, Gyeonggi, 17092, Republic of Korea
| | - Yujin Ka
- Department of Environmental Health, Graduate School at Yongin University, Yongin, Gyeonggi, 17092, Republic of Korea
| | - Bomi Lee
- Institute of Natural Science, Yongin University, Yongin, Gyeonggi, 17092, Republic of Korea
| | - Inhye Lee
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, Republic of Korea
| | - Ye Eun Seo
- Department of Food Technology & Service, Eulji University, Seongnam, Gyeonggi, 13135, Republic of Korea
| | - Hyewon Shin
- Department of Health, Environment & Safety, Eulji University, Seongnam, Gyeonggi, 13135, Republic of Korea
| | - Younglim Kho
- Department of Health, Environment & Safety, Eulji University, Seongnam, Gyeonggi, 13135, Republic of Korea
| | - Kyunghee Ji
- Department of Environmental Health, Graduate School at Yongin University, Yongin, Gyeonggi, 17092, Republic of Korea.
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Garnovskaya M, Feshuk M, Stewart W, Friedman KP, Thomas RS, Deisenroth C. Evaluation of a high-throughput H295R homogenous time resolved fluorescence assay for androgen and estrogen steroidogenesis screening. Toxicol In Vitro 2023; 92:105659. [PMID: 37557933 PMCID: PMC10903741 DOI: 10.1016/j.tiv.2023.105659] [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] [Received: 04/28/2023] [Revised: 07/06/2023] [Accepted: 08/06/2023] [Indexed: 08/11/2023]
Abstract
The H295R test guideline assay evaluates the effect of test substances on synthesis of 17β-estradiol (E2) and testosterone (T). The objective of this study was to leverage commercial immunoassay technology to develop a more efficient H295R assay to measure E2 and T levels in 384-well format. The resulting Homogenous Time Resolved Fluorescence assay platform (H295R-HTRF) was evaluated against a training set of 36 chemicals derived from the OECD inter-laboratory validation study, EPA guideline 890.1200 aromatase assay, and azole fungicides active in the HT-H295R assay. Quality control performance criteria were met for all conditions except E2 synthesis inhibition where low basal hormone synthesis was observed. Five proficiency chemicals were active for both the E2 and T endpoints, consistent with guideline classifications. Of the nine OECD core reference chemicals, 9/9 were concordant with outcomes for E2 and 7/9 for T. Likewise, 9/13 and 11/13 OECD supplemental chemicals were concordant with anticipated effects for E2 and T, respectively. Of the 10 azole fungicides screened, 7/10 for E2 and 8/10 for T exhibited concordant outcomes for inhibition. Generally, all active chemicals in the training set demonstrated equivalent or greater potency in the H295R-HTRF assay, supporting the sensitivity of the platform. The adaptation of HTRF technology to the H295R model provides an efficient way to evaluate E2 and T modulators in accordance with guideline specifications.
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Affiliation(s)
- Maria Garnovskaya
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States
| | - Madison Feshuk
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States
| | - Wendy Stewart
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States
| | - Katie Paul Friedman
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States
| | - Russell S Thomas
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States
| | - Chad Deisenroth
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States.
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Tinwell H, Karmaus A, Gaskell V, Gomes C, Grant C, Holmes T, Jonas A, Kellum S, Krüger K, Malley L, Melching-Kollmuss S, Mercier O, Pandya H, Placke T, Settivari R, De Waen B. Evaluating H295R steroidogenesis assay data for robust interpretation. Regul Toxicol Pharmacol 2023; 143:105461. [PMID: 37490962 DOI: 10.1016/j.yrtph.2023.105461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/22/2023] [Accepted: 07/21/2023] [Indexed: 07/27/2023]
Abstract
The in vitro H295R steroidogenesis assay (OECD TG 456) is used to determine a chemical's potential to interfere with steroid hormone synthesis/metabolism. As positive outcomes in this assay can trigger significant higher tiered testing, we compiled a stakeholder database of reference and test item H295R data to characterize assay outcomes. Information concerning whether a Level 5 reproductive toxicity study was triggered due to a positive outcome in the H295R assay was also included. Quality control acceptance criteria were not always achieved, suggesting this assay is challenging to conduct within the guideline specifications. Analysis of test item data demonstrated that pairwise significance testing to controls allowed for overly sensitive statistically significant positive outcomes, which likely contribute to the assay's high positive hit rate. Complementary interpretation criteria (e.g., 1.5-fold change threshold) markedly reduced the rate of equivocal and positive outcomes thus improving identification of robust positive effects in the assay. Finally, a case study (positive H295R outcome and no endocrine adversity in vivo) is presented, which suggests that stricter data interpretation criteria could refine necessary in vivo follow-up testing. Overall, the described additional criteria could improve H295R data interpretation and help inform on how to best leverage this assay for regulatory purposes.
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Affiliation(s)
- H Tinwell
- Bayer SAS, 16 Rue Jean-Marie Leclair, 69009, Lyon, France.
| | - A Karmaus
- Inotiv, 601 Keystone Park Drive, Morrisville, NC, 27560, United States
| | - V Gaskell
- Nufarm UK Ltd, Wyke Lane, Bradford, BD12 9EJ, UK
| | - C Gomes
- BASF SE, Experimental Toxicology and Ecology, Carl-Bosch-Strasse 38, 67056, Ludwigshafen, Germany
| | - C Grant
- Regulatory Science Associates, Kip Marina, Inverkip, Renfrewshire, PA16 OAS, UK
| | - T Holmes
- ADAMA Deutschland GmbH, Edmund-Rumpler-Str. 651149, Koeln (Cologne), Germany
| | - A Jonas
- Sumitomo Chemical Agro Europe, Parc D'Affaires de Crécy, 10A Rue de La Voie Lactée, 69370, Saint Didier Au Mont D'Or, France
| | - S Kellum
- Corteva Agriscience, Haskell R&D Center, 1090 Elkton Rd, Bldg 320, Newark, DE, 19711, USA
| | - K Krüger
- HELM AG, Nordkanalstrasse 28, 20097, Hamburg, Germany
| | - L Malley
- FMC, Stine Research Center, 1090 Elkton Road, Newark, DE, 19711, USA
| | | | - O Mercier
- Sumitomo Chemical Agro Europe, Parc D'Affaires de Crécy, 10A Rue de La Voie Lactée, 69370, Saint Didier Au Mont D'Or, France
| | - H Pandya
- UPL Limited, Mumbai, 400051, India
| | - T Placke
- Syngenta, Rosentalstrasse 67, CH-4058 Basel, Switzerland
| | - R Settivari
- Corteva Agriscience, Haskell R&D Center, 1090 Elkton Rd, Bldg 320, Newark, DE, 19711, USA
| | - B De Waen
- ISK, De Kleetlaan 12b, 1831, Machelen, Belgium
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Cheminformatics analysis of chemicals that increase estrogen and progesterone synthesis for a breast cancer hazard assessment. Sci Rep 2022; 12:20647. [PMID: 36450809 PMCID: PMC9712655 DOI: 10.1038/s41598-022-24889-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 11/22/2022] [Indexed: 12/03/2022] Open
Abstract
Factors that increase estrogen or progesterone (P4) action are well-established as increasing breast cancer risk, and many first-line treatments to prevent breast cancer recurrence work by blocking estrogen synthesis or action. In previous work, using data from an in vitro steroidogenesis assay developed for the U.S. Environmental Protection Agency (EPA) ToxCast program, we identified 182 chemicals that increased estradiol (E2up) and 185 that increased progesterone (P4up) in human H295R adrenocortical carcinoma cells, an OECD validated assay for steroidogenesis. Chemicals known to induce mammary effects in vivo were very likely to increase E2 or P4 synthesis, further supporting the importance of these pathways for breast cancer. To identify additional chemical exposures that may increase breast cancer risk through E2 or P4 steroidogenesis, we developed a cheminformatics approach to identify structural features associated with these activities and to predict other E2 or P4 steroidogens from their chemical structures. First, we used molecular descriptors and physicochemical properties to cluster the 2,012 chemicals screened in the steroidogenesis assay using a self-organizing map (SOM). Structural features such as triazine, phenol, or more broadly benzene ramified with halide, amine or alcohol, are enriched for E2 or P4up chemicals. Among E2up chemicals, phenol and benzenone are found as significant substructures, along with nitrogen-containing biphenyls. For P4up chemicals, phenol and complex aromatic systems ramified with oxygen-based groups such as flavone or phenolphthalein are significant substructures. Chemicals that are active for both E2up and P4up are enriched with substructures such as dihydroxy phosphanedithione or are small chemicals that contain one benzene ramified with chlorine, alcohol, methyl or primary amine. These results are confirmed with a chemotype ToxPrint analysis. Then, we used machine learning and artificial intelligence algorithms to develop and validate predictive classification QSAR models for E2up and P4up chemicals. These models gave reasonable external prediction performances (balanced accuracy ~ 0.8 and Matthews Coefficient Correlation ~ 0.5) on an external validation. The QSAR models were enriched by adding a confidence score that considers the chemical applicability domain and a ToxPrint assessment of the chemical. This profiling and these models may be useful to direct future testing and risk assessments for chemicals related to breast cancer and other hormonally-mediated outcomes.
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Foster MJ, Patlewicz G, Shah I, Haggard DE, Judson RS, Paul Friedman K. Evaluating structure-based activity in a high-throughput assay for steroid biosynthesis. COMPUTATIONAL TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 24:1-23. [PMID: 37841081 PMCID: PMC10569244 DOI: 10.1016/j.comtox.2022.100245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Data from a high-throughput human adrenocortical carcinoma assay (HT-H295R) for steroid hormone biosynthesis are available for >2000 chemicals in single concentration and 654 chemicals in multi-concentration (mc). Previously, a metric describing the effect size of a chemical on the biosynthesis of 11 hormones was derived using mc data referred to as the maximum mean Mahalanobis distance (maxmMd). However, mc HT-H295R assay data remain unavailable for many chemicals. This work leverages existing HT-H295R assay data by constructing structure-activity relationships to make predictions for data-poor chemicals, including: (1) identification of individual structural descriptors, known as ToxPrint chemotypes, associated with increased odds of affecting estrogen or androgen synthesis; (2) a random forest (RF) classifier using physicochemical property descriptors to predict HT-H295R maxmMd binary (positive or negative) outcomes; and, (3) a local approach to predict maxmMd binary outcomes using nearest neighbors (NNs) based on two types of chemical fingerprints (chemotype or Morgan). Individual chemotypes demonstrated high specificity (85-98%) for modulators of estrogen and androgen synthesis but with low sensitivity. The best RF model for maxmMd classification included 13 predicted physicochemical descriptors, yielding a balanced accuracy (BA) of 71% with only modest improvement when hundreds of structural features were added. The best two NN models for binary maxmMd prediction demonstrated BAs of 85 and 81% using chemotype and Morgan fingerprints, respectively. Using an external test set of 6302 chemicals (lacking HT-H295R data), 1241 were identified as putative estrogen and androgen modulators. Combined results across the three classification models (global RF model and two local NN models) predict that 1033 of the 6302 chemicals would be more likely to affect HT-H295R bioactivity. Together, these in silico approaches can efficiently prioritize thousands of untested chemicals for screening to further evaluate their effects on steroid biosynthesis.
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Affiliation(s)
- M J Foster
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
- National Student Services Contractor, Oak Ridge Associated Universities
| | - G Patlewicz
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
| | - I Shah
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
| | - D E Haggard
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
| | - R S Judson
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
| | - K Paul Friedman
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
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El-Masri H, Paul Friedman K, Isaacs K, Wetmore BA. Advances in computational methods along the exposure to toxicological response paradigm. Toxicol Appl Pharmacol 2022; 450:116141. [PMID: 35777528 PMCID: PMC9619339 DOI: 10.1016/j.taap.2022.116141] [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] [Received: 04/12/2022] [Revised: 05/27/2022] [Accepted: 06/23/2022] [Indexed: 10/17/2022]
Abstract
Human health risk assessment is a function of chemical toxicity, bioavailability to reach target biological tissues, and potential environmental exposure. These factors are complicated by many physiological, biochemical, physical and lifestyle factors. Furthermore, chemical health risk assessment is challenging in view of the large, and continually increasing, number of chemicals found in the environment. These challenges highlight the need to prioritize resources for the efficient and timely assessment of those environmental chemicals that pose greatest health risks. Computational methods, either predictive or investigative, are designed to assist in this prioritization in view of the lack of cost prohibitive in vivo experimental data. Computational methods provide specific and focused toxicity information using in vitro high throughput screening (HTS) assays. Information from the HTS assays can be converted to in vivo estimates of chemical levels in blood or target tissue, which in turn are converted to in vivo dose estimates that can be compared to exposure levels of the screened chemicals. This manuscript provides a review for the landscape of computational methods developed and used at the U.S. Environmental Protection Agency (EPA) highlighting their potentials and challenges.
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Affiliation(s)
- Hisham El-Masri
- Center for Computational Toxicology and Exposure, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC, USA.
| | - Katie Paul Friedman
- Center for Computational Toxicology and Exposure, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Kristin Isaacs
- Center for Computational Toxicology and Exposure, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Barbara A Wetmore
- Center for Computational Toxicology and Exposure, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC, USA
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Burgoon LD, Borgert CJ. Comment on "Application of an in Vitro Assay to Identify Chemicals That Increase Estradiol and Progesterone Synthesis and Are Potential Breast Cancer Risk Factors". ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:58002. [PMID: 35507340 PMCID: PMC9067438 DOI: 10.1289/ehp11083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
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Rudel RA, Cardona B, Borrel A, Kay JE. Response to "Comment on 'Application of an in Vitro Assay to Identify Chemicals That Increase Estradiol and Progesterone Synthesis and Are Potential Breast Cancer Risk Factors'". ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:58003. [PMID: 35507338 PMCID: PMC9067437 DOI: 10.1289/ehp11400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
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Barton-Maclaren TS, Wade M, Basu N, Bayen S, Grundy J, Marlatt V, Moore R, Parent L, Parrott J, Grigorova P, Pinsonnault-Cooper J, Langlois VS. Innovation in regulatory approaches for endocrine disrupting chemicals: The journey to risk assessment modernization in Canada. ENVIRONMENTAL RESEARCH 2022; 204:112225. [PMID: 34666016 DOI: 10.1016/j.envres.2021.112225] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Globally, regulatory authorities grapple with the challenge of assessing the hazards and risks to human and ecosystem health that may result from exposure to chemicals that disrupt the normal functioning of endocrine systems. Rapidly increasing number of chemicals in commerce, coupled with the reliance on traditional, costly animal experiments for hazard characterization - often with limited sensitivity to many important mechanisms of endocrine disruption -, presents ongoing challenges for chemical regulation. The consequence is a limited number of chemicals for which there is sufficient data to assess if there is endocrine toxicity and hence few chemicals with thorough hazard characterization. To address this challenge, regulatory assessment of endocrine disrupting chemicals (EDCs) is benefiting from a revolution in toxicology that focuses on New Approach Methodologies (NAMs) to more rapidly identify, prioritize, and assess the potential risks from exposure to chemicals using novel, more efficient, and more mechanistically driven methodologies and tools. Incorporated into Integrated Approaches to Testing and Assessment (IATA) and guided by conceptual frameworks such as Adverse Outcome Pathways (AOPs), emerging approaches focus initially on molecular interactions between the test chemical and potentially vulnerable biological systems instead of the need for animal toxicity data. These new toxicity testing methods can be complemented with in silico and computational toxicology approaches, including those that predict chemical kinetics. Coupled with exposure data, these will inform risk-based decision-making approaches. Canada is part of a global network collaborating on building confidence in the use of NAMs for regulatory assessment of EDCs. Herein, we review the current approaches to EDC regulation globally (mainly from the perspective of human health), and provide a perspective on how the advances for regulatory testing and assessment can be applied and discuss the promises and challenges faced in adopting these novel approaches to minimize risks due to EDC exposure in Canada, and our world.
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Affiliation(s)
- T S Barton-Maclaren
- Existing Substances Risk Assessment Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Canada.
| | - M Wade
- Environmental Health Centre, Environmental Health, Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - N Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Ste Anne de Bellevue, QC, Canada
| | - S Bayen
- Faculty of Agricultural and Environmental Sciences, McGill University, Ste Anne de Bellevue, QC, Canada
| | - J Grundy
- New Substances Assessment and Control Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Canada
| | - V Marlatt
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - R Moore
- New Substances Assessment and Control Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Canada
| | - L Parent
- Département Science et Technologie, Université TÉLUQ, Montréal, QC, Canada
| | - J Parrott
- Water Science and Technology Directorate, Environment and Climate Change Canada, Burlington, ON, Canada
| | - P Grigorova
- Département Science et Technologie, Université TÉLUQ, Montréal, QC, Canada
| | - J Pinsonnault-Cooper
- New Substances Assessment and Control Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Canada
| | - V S Langlois
- Institut National de la Recherche Scientifique (INRS), Centre Eau Terre Environnement, Quebec City, QC, Canada
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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: 10] [Impact Index Per Article: 3.3] [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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Cardona B, Rudel RA. Application of an in Vitro Assay to Identify Chemicals That Increase Estradiol and Progesterone Synthesis and Are Potential Breast Cancer Risk Factors. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:77003. [PMID: 34287026 PMCID: PMC8293912 DOI: 10.1289/ehp8608] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
BACKGROUND Established breast cancer risk factors, such as hormone replacement therapy and reproductive history, are thought to act by increasing estrogen and progesterone (P4) activity. OBJECTIVE We aimed to use in vitro screening data to identify chemicals that increase the synthesis of estradiol (E2) or P4 and evaluate potential risks. METHOD Using data from a high-throughput (HT) in vitro steroidogenesis assay developed for the U.S. Environmental Protection Agency (EPA) ToxCast program, we identified chemicals that increased estradiol (E2-up) or progesterone (P4-up) in human H295R adrenocortical carcinoma cells. We prioritized chemicals by their activity. We compiled in vivo studies and assessments about carcinogenicity and reproductive/developmental (repro/dev) toxicity. We identified exposure sources and predicted intakes from the U.S. EPA's ExpoCast. RESULTS We found 296 chemicals increased E2 (182) or P4 (185), with 71 chemicals increasing both. In vivo data often showed effects consistent with this mechanism. Of the E2- and P4-up chemicals, about 30% were likely repro/dev toxicants or carcinogens, whereas only 5-13% were classified as unlikely. However, most of the chemicals had insufficient in vivo data to evaluate their effects. Of 45 chemicals associated with mammary gland effects, and also tested in the H294R assay, 29 increased E2 or P4, including the well-known mammary carcinogen 7,12-dimethylbenz(a)anthracene. E2- and P4-up chemicals include pesticides, consumer product ingredients, food additives, and drinking water contaminants. DISCUSSION The U.S. EPA's in vitro screening data identified several hundred chemicals that should be considered as potential risk factors for breast cancer because they increased E2 or P4 synthesis. In vitro data is a helpful addition to current toxicity assessments, which are not sensitive to mammary gland effects. Relevant effects on the mammary gland are often not noticed or are dismissed, including for 2,4-dichlorophenol and cyfluthrin. Fifty-three active E2-up and 59 active P4-up chemicals that are in consumer products, food, pesticides, or drugs have not been evaluated for carcinogenic potential and are priorities for study and exposure reduction. https://doi.org/10.1289/EHP8608.
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Nanba K, Blinder AR, Rainey WE. Primary Cultures and Cell Lines for In Vitro Modeling of the Human Adrenal Cortex. TOHOKU J EXP MED 2021; 253:217-232. [PMID: 33840647 DOI: 10.1620/tjem.253.217] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The human adrenal cortex is a complex endocrine organ that produces mineralocorticoids, glucocorticoids and androgens. These steroids are produced in distinct cell types located within the glomerulosa, fasciculata and reticularis of the adrenal cortex. Abnormal adrenal steroidogenesis leads to a variety of diseases that can cause hypertension, metabolic syndrome, infertility and premature adrenarche. The adrenal cortex can also develop steroid-producing adenomas and rarely adrenocortical carcinomas. In vitro cell culture models provide important tools to study molecular and cellular mechanisms controlling both the physiologic and pathologic conditions of the adrenal cortex. In addition, the presence of multiple steroid-metabolizing enzymes within adrenal cells makes it a model for defining possible endocrine disruptors that might block these enzymes. The regulation and dysregulation of human adrenal steroid production and cell division/tumor growth can be studied using freshly isolated cells but this requires access to human adrenal glands, which are not available to most investigators. Immortalized human adrenocortical cell lines have proven to be of considerable value in studying the molecular and biochemical mechanisms controlling adrenal steroidogenesis and tumorigenesis. Current human adrenal cell lines include the original NCI-H295 and its substrains: H295A, H295R, HAC13, HAC15, HAC50 and H295RA as well as the recently established MUC-1, CU-ACC1 and CU-ACC2. The current review will discuss the use of primary cultures of fetal and adult adrenal cells as well as adrenocortical cell lines as in vitro models for the study of human adrenal physiology and pathophysiology.
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Affiliation(s)
- Kazutaka Nanba
- Department of Molecular and Integrative Physiology, University of Michigan.,Department of Endocrinology and Metabolism, National Hospital Organization Kyoto Medical Center
| | - Amy R Blinder
- Department of Molecular and Integrative Physiology, University of Michigan
| | - William E Rainey
- Department of Molecular and Integrative Physiology, University of Michigan.,Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan
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14
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Cardona B, Rudel RA. US EPA's regulatory pesticide evaluations need clearer guidelines for considering mammary gland tumors and other mammary gland effects. Mol Cell Endocrinol 2020; 518:110927. [PMID: 32645345 PMCID: PMC9183204 DOI: 10.1016/j.mce.2020.110927] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/03/2020] [Accepted: 06/23/2020] [Indexed: 01/05/2023]
Abstract
Breast cancer risk from pesticides may be missed if effects on mammary gland are not assessed in toxicology studies required for registration. Using US EPA's registration documents, we identified pesticides that cause mammary tumors or alter development, and evaluated how those findings were considered in risk assessment. Of 28 pesticides that produced mammary tumors, EPA's risk assessment acknowledges those tumors for nine and dismisses the remaining cases. For five pesticides that alter mammary gland development, the implications for lactation and cancer risk are not assessed. Many of the mammary-active pesticides activate pathways related to endocrine disruption: altering steroid synthesis in H295R cells, activating nuclear receptors, or affecting xenobiotic metabolizing enzymes. Clearer guidelines based on breast cancer biology would strengthen assessment of mammary gland effects, including sensitive histology and hormone measures. Potential cancer risks from several common pesticides should be re-evaluated, including: malathion, triclopyr, atrazine, propylene oxide, and 3-iodo-2-propynyl butylcarbamate (IPBC).
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15
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Nyffeler J, Haggard DE, Willis C, Setzer RW, Judson R, Paul-Friedman K, Everett LJ, Harrill JA. Comparison of Approaches for Determining Bioactivity Hits from High-Dimensional Profiling Data. SLAS DISCOVERY 2020; 26:292-308. [PMID: 32862757 DOI: 10.1177/2472555220950245] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phenotypic profiling assays are untargeted screening assays that measure a large number (hundreds to thousands) of cellular features in response to a stimulus and often yield diverse and unanticipated profiles of phenotypic effects, leading to challenges in distinguishing active from inactive treatments. Here, we compare a variety of different strategies for hit identification in imaging-based phenotypic profiling assays using a previously published Cell Painting data set. Hit identification strategies based on multiconcentration analysis involve curve fitting at several levels of data aggregation (e.g., individual feature level, aggregation of similarly derived features into categories, and global modeling of all features) and on computed metrics (e.g., Euclidean and Mahalanobis distance metrics and eigenfeatures). Hit identification strategies based on single-concentration analysis included measurement of signal strength (e.g., total effect magnitude) and correlation of profiles among biological replicates. Modeling parameters for each approach were optimized to retain the ability to detect a reference chemical with subtle phenotypic effects while limiting the false-positive rate to 10%. The percentage of test chemicals identified as hits was highest for feature-level and category-based approaches, followed by global fitting, whereas signal strength and profile correlation approaches detected the fewest number of active hits at the fixed false-positive rate. Approaches involving fitting of distance metrics had the lowest likelihood for identifying high-potency false-positive hits that may be associated with assay noise. Most of the methods achieved a 100% hit rate for the reference chemical and high concordance for 82% of test chemicals, indicating that hit calls are robust across different analysis approaches.
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Affiliation(s)
- Johanna Nyffeler
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, NC, USA.,Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | - Derik E Haggard
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, NC, USA.,Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | - Clinton Willis
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, NC, USA.,Oak Ridge Associated Universities (ORAU), Oak Ridge, TN, USA
| | - R Woodrow Setzer
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, NC, USA
| | - Richard Judson
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, NC, USA
| | - Katie Paul-Friedman
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, NC, USA
| | - Logan J Everett
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, NC, USA
| | - Joshua A Harrill
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, NC, USA
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