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Indole-3-Carbinol, a Phytochemical Aryl Hydrocarbon Receptor-Ligand, Induces the mRNA Overexpression of UBE2L3 and Cell Proliferation Arrest. Curr Issues Mol Biol 2022; 44:2054-2068. [PMID: 35678668 PMCID: PMC9164055 DOI: 10.3390/cimb44050139] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/28/2022] [Accepted: 05/05/2022] [Indexed: 11/17/2022] Open
Abstract
Cervical cancer (CC) is one of the most common cancers in women, and is linked to human papillomavirus (HPV) infection. The virus oncoprotein E6 binds to p53, resulting in its degradation and allowing uncontrolled cell proliferation. Meanwhile, the HPV E7 protein maintains host cell differentiation by targeting retinoblastoma tumor suppressor. The host cell can ubiquitinate E6 and E7 through UBE2L3, whose expression depends on the interaction between the aryl hydrocarbon receptor (AhR) with Xenobiotic Responsive Elements (XREs) located in the UBE2L3 gene promoter. In this study, we used cell culture to determine the effect of indole-3-carbinol (I3C) over cellular viability, apoptosis, cell proliferation, and mRNA levels of UBE2L3 and CYP1A1. In addition, patients’ samples were used to determine the mRNA levels of UBE2L3 and CYP1A1 genes. We found that I3C promotes the activation of AhR and decreases cell proliferation, possibly through UBE2L3 mRNA induction, which would result in the ubiquitination of HPV E7. Since there is a strong requirement for selective and cost-effective cancer treatments, natural AhR ligands such as I3C could represent a novel strategy for cancer treatment.
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2
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Saito N, Kanno Y, Yamashita N, Degawa M, Yoshinari K, Nemoto K. The Differential Selectivity of Aryl Hydrocarbon Receptor (AHR) Agonists towards AHR-Dependent Suppression of Mammosphere Formation and Gene Transcription in Human Breast Cancer Cells. Biol Pharm Bull 2021; 44:571-578. [PMID: 33790107 DOI: 10.1248/bpb.b20-00961] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We had previously reported that treatment with the aryl hydrocarbon receptor (AHR) agonist β-naphthoflavone (βNF) suppressed mammosphere formation derived from cancer stem cells in human breast cancer MCF-7 cells (Cancer Lett., 317, 2012, Zhao et al.). Here, using several AHR agonists, we have investigated the association of this suppression with the classical ability to induce AHR-mediated gene transcription in the xenobiotic response element (XRE). The mammosphere formation assays were performed using wild-type and AHR-knockout MCF-7 cells in the presence of AHR agonists including 3-methylcholanthrene (3MC), benzo[a]pyrene (BaP), 7,12-dimethylbenz[a]anthracene (DMBA), 6-formylindolo[3,2-b]carbazole (FICZ), indirubin, indole-3-carbinol (I3C), indole-3-acetic acid (IAA), and kynurenine (KYN), followed by the XRE-reporter gene assays of the agonists. We showed that treatments with 3MC, BaP, and DMBA strongly suppressed mammosphere formation of the stem cells in an AHR-dependent manner, while other agonists showed weaker suppression. In reporter gene assays, the strength or duration of AHR/XRE-mediated gene transcription was found to be dependent on the agonist. Although strong transcriptional activation was observed with 3MC, FICZ, indirubin, I3C, IAA, or KYN after 6 h of treatment, only weak activation was seen with BaP or DMBA. While transcriptional activation was sustained or increased at 24 h with 3MC, BaP, or DMBA, appreciable reduction was observed with the other agonists. In conclusions, the results demonstrated that the suppressive effects of AHR agonists on mammosphere formation do not necessarily correlate with their abilities to induce AHR-mediated gene transcription. Hence, different AHR functions may be differentially induced in an agonist-dependent manner.
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Affiliation(s)
- Nao Saito
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University
| | - Yuichiro Kanno
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University.,Laboratory of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka
| | - Naoya Yamashita
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University.,Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts
| | - Masakuni Degawa
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University.,Laboratory of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka
| | - Kouichi Yoshinari
- Laboratory of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka
| | - Kiyomitsu Nemoto
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University
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3
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Furukawa S, Tsuji N, Hayashi S, Kuroda Y, Kimura M, Hayakawa C, Takeuchi K, Sugiyama A. The effects of β-naphthoflavone on rat placental development. J Toxicol Pathol 2019; 32:275-282. [PMID: 31719754 PMCID: PMC6831496 DOI: 10.1293/tox.2019-0047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 07/23/2019] [Indexed: 01/21/2023] Open
Abstract
The morphological effects of β-naphthoflavone (β-NF) on placental development in
pregnant rats were examined. β-NF, administered to pregnant rats intraperitoneally at 15
mg/kg bw from gestation day (GD) 9 to GD 14, had no effect on maternal body weight gain,
mortality, or clinical sign. In the β-NF-exposed rats, intrauterine growth retardation
(IUGR) rates increased on GDs 17 and 21, although there was no effect on fetal mortality
rate, fetal or placental weight, or external fetal abnormality. Histopathologically, β-NF
induced apoptosis and inhibition of cell proliferation of the trophoblastic septa in the
labyrinth zone, resulting in its poor development. In the basal zone, β-NF induced
spongiotrophoblast apoptosis and delayed glycogen islet regression, resulting in their
cystic degeneration. β-NF-induced CYP1A1 expression was detected in the endothelial cells
of the fetal capillaries in the labyrinth zone and in the endothelial cells of the spiral
arteries in the metrial gland, but not in any trophoblasts. This indicates that CYP1A1 is
inducible in the endothelial cells of the fetal capillaries in the labyrinth zone, and
that these cells have an important role in metabolizing CYP1A1 inducers crossing the
placental barrier.
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Affiliation(s)
- Satoshi Furukawa
- Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Naho Tsuji
- Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Seigo Hayashi
- Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Yusuke Kuroda
- Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Masayuki Kimura
- Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Chisato Hayakawa
- Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Kazuya Takeuchi
- Biological Research Laboratories, Nissan Chemical Corporation, 1470 Shiraoka, Shiraoka-shi, Saitama 349-0294, Japan
| | - Akihiko Sugiyama
- Veterinary Clinical Pathology, Faculty of Veterinary Medicine Okayama University of Science, 1-3 Ikoinooka, Imabari, Ehime 794-8555, Japan
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4
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Matz DK, Chuck J, Hosmer RJ, Piper HC, Link JE, Fitzgerald SD, Steibel JP, Bursian SJ. Induction of maxillary and mandibular squamous epithelial cell proliferation in mink (Neovison vison) by β-naphthoflavone. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2019; 38:460-463. [PMID: 30525228 DOI: 10.1002/etc.4329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 08/27/2018] [Accepted: 12/03/2018] [Indexed: 06/09/2023]
Abstract
A jaw lesion reported in mink exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD-like chemicals is considered a potential indicator of exposure to these chemicals. Many of the effects of TCDD-like chemicals are induced through interaction with the aryl hydrocarbon receptor. The present study indicates that mink dosed with β-naphthoflavone, which is an aryl hydrocarbon receptor ligand but not a TCDD-like chemical, also develop the lesion. Environ Toxicol Chem 2019;38:460-463. © 2018 SETAC.
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Affiliation(s)
- Danielle K Matz
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing Michigan, USA
| | - Joanna Chuck
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
| | - Robin J Hosmer
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
| | - Hannah C Piper
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
| | - Jane E Link
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
| | - Scott D Fitzgerald
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan, USA
- Michigan State University Veterinary Diagnostic Laboratory, Lansing, Michigan, USA
| | - Juan P Steibel
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
| | - Steven J Bursian
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
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5
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β-Naphthoflavone-Induced Mitochondrial Respiratory Damage in Cyp1 Knockout Mouse and in Cell Culture Systems: Attenuation by Resveratrol Treatment. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:5213186. [PMID: 29098061 PMCID: PMC5618780 DOI: 10.1155/2017/5213186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/15/2017] [Indexed: 12/21/2022]
Abstract
A number of xenobiotic-inducible cytochrome P450s (CYPs) are now known to be localized in the mitochondrial compartment, though their pharmacological or toxicological roles remain unclear. Here, we show that BNF treatment markedly inhibits liver mitochondrial O2 consumption rate (OCR), ADP-dependent OCR, and also reserve OCR, in wild-type mice but not in Cyp1a1/1a2(-/-) double knockout mice. BNF treatment markedly affected mitochondrial complex I and complex IV activities and also attenuated mitochondrial gene expression. Furthermore, under in vitro conditions, BNF treatment induced cellular ROS production, which was inhibited by mitochondria-targeted antioxidant Mito-CP and CYP inhibitor proadefin, suggesting that most of the ROS production was intramitochondrial and probably involved the catalytic activity of mitochondrial CYP1 enzymes. Interestingly, our results also show that the AHR antagonist resveratrol, markedly attenuated BNF-induced liver mitochondrial defects in wild-type mice, confirming the role of AHR and AHR-regulated CYP1 genes in eliciting mitochondrial dysfunction. These results are consistent with reduced BNF-induced mitochondrial toxicity in Cyp1a1/1a2(-/-) mice and elevated ROS production in COS cells stably expressing CYP1A1. We propose that increased mitochondrial ROS production and respiratory dysfunction are part of xenobiotic toxicity. Resveratrol, a chemopreventive agent, renders protection against BNF-induced toxicity.
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Kimura M, Mizukami S, Watanabe Y, Onda N, Yoshida T, Shibutani M. Aberrant cell cycle regulation in rat liver cells induced by post-initiation treatment with hepatocarcinogens/hepatocarcinogenic tumor promoters. ACTA ACUST UNITED AC 2016; 68:399-408. [PMID: 27402199 DOI: 10.1016/j.etp.2016.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/22/2016] [Accepted: 06/07/2016] [Indexed: 01/23/2023]
Abstract
The present study aimed to determine the onset time of hepatocarcinogen/hepatocarcinogenic tumor promoter-specific cell proliferation, apoptosis and aberrant cell cycle regulation after post-initiation treatment. Six-week-old rats were treated with the genotoxic hepatocarcinogen, carbadox (CRB), the marginally hepatocarcinogenic leucomalachite green (LMG), the tumor promoter, β-naphthoflavone (BNF) or the non-carcinogenic hepatotoxicant, acetaminophen, for 2, 4 or 6 weeks during the post-initiation phase using a medium-term liver bioassay. Cell proliferation activity, expression of G2 to M phase- and spindle checkpoint-related molecules, and apoptosis were immunohistochemically analyzed at week 2 and 4, and tumor promotion activity was assessed at week 6. At week 2, hepatocarcinogen/tumor promoter-specific aberrant cell cycle regulation was not observed. At week 4, BNF and LMG increased cell proliferation together with hepatotoxicity, while CRB did not. Additionally, BNF and CRB reduced the number of cells expressing phosphorylated-histone H3 in both ubiquitin D (UBD)(+) cells and Ki-67(+) proliferating cells, suggesting development of spindle checkpoint dysfunction, regardless of cell proliferation activity. At week 6, examined hepatocarcinogens/tumor promoters increased preneoplastic hepatic foci expressing glutathione S-transferase placental form. These results suggest that some hepatocarcinogens/tumor promoters increase their toxicity after post-initiation treatment, causing regenerative cell proliferation. In contrast, some genotoxic hepatocarcinogens may disrupt the spindle checkpoint without facilitating cell proliferation at the early stage of tumor promotion. This suggests that facilitation of cell proliferation and disruption of spindle checkpoint function are induced by different mechanisms during hepatocarcinogenesis. Four weeks of post-initiation treatment may be sufficient to induce hepatocarcinogen/tumor promoter-specific cellular responses.
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Affiliation(s)
- Masayuki Kimura
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan; Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Sayaka Mizukami
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan; Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Yousuke Watanabe
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan; Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Nobuhiko Onda
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Toshinori Yoshida
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Makoto Shibutani
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.
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7
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Hsu SY, Liou JW, Cheng TL, Peng SY, Lin CC, Chu YY, Luo WC, Huang ZK, Jiang SJ. beta-Naphthoflavone protects from peritonitis by reducing TNF-alpha-induced endothelial cell activation. Pharmacol Res 2015; 102:192-9. [PMID: 26453957 DOI: 10.1016/j.phrs.2015.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 10/01/2015] [Accepted: 10/02/2015] [Indexed: 01/06/2023]
Abstract
β-Naphthoflavone (β-NF), a ligand of the aryl hydrocarbon receptor, has been shown to possess anti-oxidative properties. We investigated the anti-oxidative and anti-inflammatory potential of β-NF in human microvascular endothelial cells treated with tumor necrosis factor-alpha (TNF-α). Pretreatment with β-NF significantly inhibited TNF-α-induced intracellular reactive oxygen species, translocation of p67(phox), and TNF-α-induced monocyte binding and transmigration. In addition, β-NF significantly inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. The mRNA expression levels of the inflammatory cytokines TNF-α and IL-6 were reduced by β-NF, as was the infiltration of white blood cells, in a peritonitis model. The inhibition of adhesion molecules was associated with suppressed nuclear translocation of NF-κB p65 and Akt, and suppressed phosphorylation of ERK1/2 and p38. The translocation of Egr-1, a downstream transcription factor involved in the MEK-ERK signaling pathway, was suppressed by β-NF treatment. Our findings show that β-NF inhibits TNF-α-induced NF-kB and ERK1/2 activation and ROS generation, thereby suppressing the expression of adhesion molecules. This results in reduced adhesion and transmigration of leukocytes in vitro and prevents the infiltration of leukocytes in a peritonitis model. Our findings also suggest that β-NF might prevent TNF-α-induced inflammation.
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Affiliation(s)
- Sheng-Yao Hsu
- Department ofOphthalmology,ChinaMedicalUniversity-AnNan Hospital,Tainan,Taiwan.; School of Medicine, China Medical University, Taichung, Taiwan
| | - Je-Wen Liou
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Tsung-Lin Cheng
- Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Orthopaedic Research Center, College of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shih-Yi Peng
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Chi-Chen Lin
- Institute of Biomedical Sciences, College of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Yuan-Yuan Chu
- Postgraduate program in Biochemistry, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Wei-Cheng Luo
- Master program in Microbiology, Immunology and Biochemistry, School of Medicine Master Thesis, Tzu Chi University, Hualien, Taiwan
| | - Zheng-Kai Huang
- Bachelor in Department of Molecular Biology and Human Genetics, College of Life Sciences, Tzu Chi University, Hualien, Taiwan
| | - Shinn-Jong Jiang
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien, Taiwan.
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Yamada F, Sumida K, Saito K. An improved model of predicting hepatocarcinogenic potential in rats by using gene expression data. J Appl Toxicol 2015. [PMID: 26198598 DOI: 10.1002/jat.3184] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Carcinogenicity studies using animals are expensive and time consuming. Therefore, the development of a highly accurate carcinogenicity prediction system to interpret short-term test results would be beneficial. The Ames test is popular for mutagens; however, it cannot detect non-genotoxic carcinogens. Previously, we reported a prediction system using gene expression data obtained from a short-term (28-day) study that screened candidate compounds for testing in long-term carcinogenicity studies. In this study, our system was improved by adding more gene expression data. To establish our new system, we used the data of 93 test compounds (41 hepatocarcinogens and 52 non-hepatocarcinogens). Analysis of liver gene expression data by dividing compounds into 'for training' and 'for test' categories (20 cases assigned randomly) using Support Vector Machine (SVM) identified a set of marker probe sets that could be used to predict hepatocarcinogenicity. The assigned 42 probe sets have included the cancer- or c-Myc-related genes such as Hsp90, Pink1, Hspc111, Fbx29, Hepsin, Syndecan2 and Synbindin. Compared with the older version, the improved system had a higher concordance rate with the training data and a good performance with the external test data.
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Affiliation(s)
- Fumihiro Yamada
- Sumitomo Chemical Co., Ltd., 3-1-98 Kasugadenaka, Konohana-ku, Osaka, 554-8558, Japan
| | - Kayo Sumida
- Sumitomo Chemical Co., Ltd., 3-1-98 Kasugadenaka, Konohana-ku, Osaka, 554-8558, Japan
| | - Koichi Saito
- Sumitomo Chemical Co., Ltd., 3-1-98 Kasugadenaka, Konohana-ku, Osaka, 554-8558, Japan
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9
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Henderson CJ, McLaughlin LA, Osuna-Cabello M, Taylor M, Gilbert I, McLaren AW, Wolf CR. Application of a novel regulatable Cre recombinase system to define the role of liver and gut metabolism in drug oral bioavailability. Biochem J 2015; 465:479-88. [PMID: 25377919 PMCID: PMC6949133 DOI: 10.1042/bj20140582] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The relative contribution of hepatic compared with intestinal oxidative metabolism is a crucial factor in drug oral bioavailability and therapeutic efficacy. Oxidative metabolism is mediated by the cytochrome P450 mono-oxygenase system to which cytochrome P450 reductase (POR) is the essential electron donor. In order to study the relative importance of these pathways in drug disposition, we have generated a novel mouse line where Cre recombinase is driven off the endogenous Cyp1a1 gene promoter; this line was then crossed on to a floxed POR mouse. A 40 mg/kg dose of the Cyp1a1 inducer 3-methylcholanthrene (3MC) eliminated POR expression in both liver and small intestine, whereas treatment at 4 mg/kg led to a more targeted deletion in the liver. Using this approach, we have studied the pharmacokinetics of three probe drugs--paroxetine, midazolam, nelfinavir--and show that intestinal metabolism is a determinant of oral bioavailability for the two latter compounds. The Endogenous Reductase Locus (ERL) mouse represents a significant advance on previous POR deletion models as it allows direct comparison of hepatic and intestinal effects on drug and xenobiotic clearance using lower doses of a single Cre inducing agent, and in addition minimizes any cytotoxic effects, which may compromise interpretation of the experimental data.
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Affiliation(s)
- Colin J. Henderson
- Division of Cancer Research, Level 9, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, U.K
| | - Lesley A. McLaughlin
- Division of Cancer Research, Level 9, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, U.K
| | - Maria Osuna-Cabello
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Malcolm Taylor
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Ian Gilbert
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
| | - Aileen W. McLaren
- Division of Cancer Research, Level 9, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, U.K
| | - C. Roland Wolf
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
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10
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Kimura M, Mizukami S, Watanabe Y, Hasegawa-Baba Y, Onda N, Yoshida T, Shibutani M. Disruption of spindle checkpoint function ahead of facilitation of cell proliferation by repeated administration of hepatocarcinogens in rats. J Toxicol Sci 2015; 40:855-71. [DOI: 10.2131/jts.40.855] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Masayuki Kimura
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology
- Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University
| | - Sayaka Mizukami
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology
- Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University
| | - Yousuke Watanabe
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology
- Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University
| | - Yasuko Hasegawa-Baba
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology
| | - Nobuhiko Onda
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology
| | - Toshinori Yoshida
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology
| | - Makoto Shibutani
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology
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11
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Heinrich P, Diehl U, Förster F, Braunbeck T. Improving the in vitro ethoxyresorufin-O-deethylase (EROD) assay with RTL-W1 by metabolic normalization and use of β-naphthoflavone as the reference substance. Comp Biochem Physiol C Toxicol Pharmacol 2014; 164:27-34. [PMID: 24768776 DOI: 10.1016/j.cbpc.2014.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 04/03/2014] [Accepted: 04/10/2014] [Indexed: 01/07/2023]
Abstract
The ethoxyresorufin-O-deethylase (EROD) assay is a widely applied method for the evaluation of the dioxin-like activity of single substances and environmental samples. As for most enzyme assays, the specific activity is normally related to total protein contents, the determination of which has clear limitations in high-throughput assays. EROD induction potentials are usually expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents, a substance highly toxic to humans. In order to compensate for these shortcomings, two modifications of the EROD protocol are proposed: (1) EROD activity is normalized to the metabolic activity of the cells as determined by a modified thiazolyl blue tetrazolium (MTT) assay and expressed as metabolic cell equivalents (MCE) based on MTT data rather than to protein contents. Via MCE data, cytotoxicity information can always be reported in parallel to EROD data; with the protocol presented here, MTT and EROD data are collected simultaneously. (2) Among several reference substances tested (2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), β-naphthoflavone and benzo[a]pyrene), β-naphthoflavone proved to be the most suitable reference for the routine in vitro EROD assay, although TCDD has generally been preferred for purely scientific reasons.
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Affiliation(s)
- Patrick Heinrich
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, D-69120 Heidelberg, Germany.
| | - Ulrike Diehl
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, D-69120 Heidelberg, Germany
| | - Franziska Förster
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, D-69120 Heidelberg, Germany
| | - Thomas Braunbeck
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, D-69120 Heidelberg, Germany
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12
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AhR signalling and dioxin toxicity. Toxicol Lett 2013; 230:225-33. [PMID: 24239782 DOI: 10.1016/j.toxlet.2013.10.039] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/14/2013] [Accepted: 10/18/2013] [Indexed: 12/02/2022]
Abstract
Dioxins are a family of molecules associated to several industrial accidents such as Ludwigshafen in 1953 or Seveso in 1976, to the Agent Orange used during the war of Vietnam, and more recently to the poisoning of the former president of Ukraine, Victor Yushchenko. These persistent organic pollutants are by-products of industrial activity and bind to an intracellular receptor, AhR, with a high potency. In humans, exposure to dioxins, in particular 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces a cutaneous syndrome known as chloracne, consisting in the development of many small skin lesions (hamartoma), lasting for 2-5 years. Although TCDD has been classified by the WHO as a human carcinogen, its carcinogenic potential to humans is not clearly demonstrated. It was first believed that AhR activation accounted for most, if not all, biological properties of dioxins. However, certain AhR agonists found in vegetables do not induce chloracne, and other chemicals, in particular certain therapeutic agents, may induce a chloracne-like syndrome without activating AhR. It is time to rethink the mechanism of dioxin toxicity and analyse in more details the biological events following exposure to these compounds and other AhR agonists, some of which have a very different chemical structure than TCDD. In particular various food-containing AhR agonists are non-toxic and may on the contrary have beneficial properties to human health.
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Nault R, Forgacs AL, Dere E, Zacharewski TR. Comparisons of differential gene expression elicited by TCDD, PCB126, βNF, or ICZ in mouse hepatoma Hepa1c1c7 cells and C57BL/6 mouse liver. Toxicol Lett 2013; 223:52-9. [PMID: 23994337 DOI: 10.1016/j.toxlet.2013.08.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/17/2013] [Accepted: 08/19/2013] [Indexed: 12/21/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a promiscuous receptor activated by structurally diverse synthetic and natural compounds. AhR activation may lead to ligand-specific changes in gene expression despite similarities in mode of action. Therefore, differential gene expression elicited by four structurally diverse, high affinity AhR ligands (2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 10nM, 30 μg/kg), 3,3',4,4',5-pentachlorobiphenyl (PCB126; 100nM, 300μg/kg), β-naphthoflavone (βNF; 10 μM, 90 mg/kg), and indolo[3,2-b]carbazole (ICZ; 1μM)) in mouse Hepa1c1c7 hepatoma cells and C57BL/6 mouse liver samples were compared. A total of 288, 183, 119, and 131 Hepa1c1c7 genes were differentially expressed (|fold-change|≥ 1.5, P1(t)≥ 0.9999) by TCDD, βNF, PCB126, and ICZ, respectively. Only ∼35% were differentially expressed by all 4 ligands in Hepa1c1c7 cells. In vivo, 661, 479, and 265 hepatic genes were differentially expressed following treatment with TCDD, βNF, and PCB126, respectively. Similar to Hepa1c1c7 cells, ≤ 34% of gene expression changes were common across all ligands. Principal components analysis identified time-dependent gene expression divergence. Comparisons of ligand-elicited expression between Hepa1c1c7 cells and mouse liver identified only 11 common gene expression changes across all ligands. Although metabolism may explain some ligand-specific gene expression changes, PCB126, βNF, and ICZ also elicited divergent expression compared to TCDD, suggestive of selective AhR modulation.
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Affiliation(s)
- Rance Nault
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA
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Wang B, Robertson LW, Wang K, Ludewig G. Species difference in the regulation of cytochrome P450 2S1: lack of induction in rats by the aryl hydrocarbon receptor agonist PCB126. Xenobiotica 2011; 41:1031-43. [PMID: 21970748 DOI: 10.3109/00498254.2011.603763] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CYP2S1 is an evolutionarily conserved, mainly extra-hepatic member of the CYP2 family and proposed to be regulated by the aryl hydrocarbon receptor (AhR). The present study explores AhR's regulation of CYP2S1 in male Sprague Dawley rats using PCB126 (3,3',4,4',5-pentachlorobiphenyl), the most potent AhR agonist among the PCBs. Additionally, CYP2S1 expression was examined after treatments with the classic CYP-inducers β-naphthoflavone (β-NF, AhR activator), phenobarbital (PB, CAR activator) and dexamethasone (Dex, PXR activator). CYP2S1 and CYP1A1/2, CYP1B1, CYP2B and CYP3A mRNAs were measured in liver, lung, spleen, stomach, kidney, and thymus at different time points. Constitutive CYP2S1 was expressed at comparable levels to other CYPs with the highest expression levels in stomach, kidney and lung. CYP2S1 mRNA was only non-significantly elevated by β-NF in liver tissues. PCB126 did not increase CYP2S1 mRNA in any organ and at any time point examined despite a significant induction of CYP1 genes. PCB126 reduced CYP2S1 mRNA by 40% (not significant) from the 7th post-exposure day in thymus. PB and Dex had no effect on CYP2S1 mRNA levels. These observations show that in this model CYP2S1 is not, or only weakly, regulated by AhR and not induced by CAR or PXR activators.
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Affiliation(s)
- Bingxuan Wang
- Human Toxicology, University of Iowa, Iowa City, USA
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15
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Ahmad I, Maria VL, Oliveira M, Pacheco M, Santos MA. Modulatory role of copper on β-naphthoflavone-induced DNA damage in European eel (Anguilla anguilla L.). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2008; 71:806-812. [PMID: 18304634 DOI: 10.1016/j.ecoenv.2008.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 01/08/2008] [Accepted: 01/11/2008] [Indexed: 05/26/2023]
Abstract
Gill and kidney DNA integrity (alkaline unwinding assay) was assessed in Anguilla anguilla exposed for 24-h to copper (Cu: 1 or 2.5 μM), with or without 24-h pre-exposure to a polycyclic aromatic hydrocarbon (PAH)-like compound--β-naphthoflavone (BNF: 2.7 μM). Gill showed DNA integrity loss in all the exposure conditions, reflecting a dual mode of BNF-Cu interaction depending on the metal concentration. Thus, antagonistic or additive effects were observed for BNF+Cu 1 μM or BNF+Cu 2.5 μM, respectively. Kidney showed decreased DNA integrity for single exposures (BNF, Cu 1 μM), whereas sequential exposures displayed higher DNA integrity than BNF alone, revealing a Cu antagonistic effect at both the concentrations. The results also demonstrated that (i) both organs are receptive for Cu inhibitory role against BNF genotoxicity; (ii) kidney is more resistant to Cu individual exposures; and (iii) under multi-pollution conditions genotoxicity cannot be predicted on the basis of individual chemicals responses.
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Affiliation(s)
- I Ahmad
- CESAM & Animal Physiology/Ecotoxicology Sector, Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal.
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16
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Brauze D, Widerak M, Cwykiel J, Szyfter K, Baer-Dubowska W. The effect of aryl hydrocarbon receptor ligands on the expression of AhR, AhRR, ARNT, Hif1alpha, CYP1A1 and NQO1 genes in rat liver. Toxicol Lett 2006; 167:212-20. [PMID: 17069994 DOI: 10.1016/j.toxlet.2006.09.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 09/26/2006] [Accepted: 09/26/2006] [Indexed: 11/21/2022]
Abstract
The aryl hydrocarbon receptor (AhR) mediates a variety of biological responses to ubiquitous environmental pollutants. AhR together with ARNT, AhRR, HIF1alpha represent a novel basic helix-loop-helix/PAS family of transcriptional regulators. Their interplay may affect the xenobiotic response. In this study, the effect of i.p. administration of different AhR ligands on the expression of AhR, AhRR, ARNT, HIF1alpha and CYP1A1 and NAD(P)H: quinone oxidoreductase (NQO1), the enzymes controlled by AhR were examined in Sprague-Dawley rat liver. Quantitative real-time RT-PCR analysis revealed no changes in the mRNA expression of ARNT and HIF1alpha following 3-methylcholanthrene (3-MC), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or beta-naphthoflavone (BNF) treatment. AhRR expression was affected by TCDD but not by BNF and 3-MC. Expression of AhR mRNA and of the markers of its activation, CYP1A1 and NQO1, was significantly increased by administration of TCDD, 3-MC and, to lower extent, BNF. These results indicate that binding of the ligands to AhR up-regulates the mRNA transcription not only of CYP1A1 and NQO1, but also of AhR itself. The level of AhR induction depends on the potency of xenobiotic metabolizing enzymes inducer.
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Affiliation(s)
- Damian Brauze
- Institute of Human Genetics, Polish Academy of Sciences, ul. Strzeszyńska 32, 60-479 Poznań, Poland.
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Springman KR, Kurath G, Anderson JJ, Emlen JM. Contaminants as viral cofactors: assessing indirect population effects. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2005; 71:13-23. [PMID: 15642628 DOI: 10.1016/j.aquatox.2004.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Revised: 09/23/2004] [Accepted: 10/04/2004] [Indexed: 05/24/2023]
Abstract
Current toxicological methods often miss contaminant effects, particularly when immune suppression is involved. The failure to recognize and evaluate indirect and sublethal effects severely limits the applicability of those methods at the population level. In this study, the Vitality model is used to evaluate the population level effects of a contaminant exerting only indirect, sublethal effects at the individual level. Juvenile rainbow trout (Oncorhynchus mykiss) were injected with 2.5 or 10.0 mg/kg doses of the model CYP1A inducer, beta-naphthoflavone (BNF) as a pre-stressor, then exposed to a challenge dose of 10(2) or 10(4) pfu/fish of infectious hematopoietic necrosis virus (IHNV), an important viral pathogen of salmonids in North America. At the end of the 28-d challenge, the mortality data were processed according to the Vitality model which indicated that the correlation between the average rate of vitality loss and the pre-stressor dose was strong: R2=0.9944. Average time to death and cumulative mortality were dependent on the BNF dose, while no significant difference between the two viral dosages was shown, implying that the history of the organism at the time of stressor exposure is an important factor in determining the virulence or toxicity of the stressor. The conceptual framework of this model permits a smoother transfer of results to a more complex stratum, namely the population level, which allows the immunosuppressive results generated by doses of a CYP1A inducer that more accurately represent the effects elicited by environmentally-relevant contaminant concentrations to be extrapolated to target populations. The indirect effects of other environmental contaminants with similar biotransformation pathways, such as polycyclic aromatic hydrocarbons (PAH), could be assessed and quantified with this model and the results applied to a more complex biological hierarchy.
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Affiliation(s)
- Kathrine R Springman
- Columbia Basin Research, School of Fisheries, University of Washington, Puget Sound Plaza, 1325 4th Avenue, Suite 1820, Seattle, WA 98101-2509, USA.
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Teles M, Pacheco M, Santos MA. Anguilla anguilla L. liver ethoxyresorufin O-deethylation, glutathione S-transferase, erythrocytic nuclear abnormalities, and endocrine responses to naphthalene and beta-naphthoflavone. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2003; 55:98-107. [PMID: 12706398 DOI: 10.1016/s0147-6513(02)00134-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effects of naphthalene (NAP) and beta-naphthoflavone (BNF) on phase I biotransformation and genotoxicity in Anguilla anguilla L. were evaluated. Phase II biotransformation and cortisol levels were also assessed in NAP-treated fish. Two groups of eels were exposed to either a NAP or a BNF concentration range (0.1-2.7 microM) for different exposure periods (2-72 h). An early significant ethoxyresorufin O-deethylation (EROD) activity inhibition was observed, especially for the highest NAP concentrations at 2-6 h exposure and for BNF at 2h exposure. However, a significant EROD activity increase was detected from 16 to 72 h exposure for NAP and from 4 to 72 h exposure for BNF. The cytochrome P450 (P450) content was not dose related. However, with regard to BNF exposure, P450 was the first biomarker to respond. Liver alanine transaminase (ALT) activity was measured as an indicator of hepatic health condition. ALT results demonstrated that the EROD activity decrease, previously described for NAP, was not related to tissue damage. Nevertheless, the highest BNF concentrations were demonstrated to induce liver damage and to impair the EROD activity response. An increased genotoxic response, measured as erythrocytic nuclear abnormalities (ENA), was observed during the first 8h NAP exposure. However, for exposures longer than 8 h, ENA frequency returned to the control levels. This response profile may reflect a considerable DNA repair capacity and/or a metabolic adaptation providing an efficient NAP biotransformation and consequent detoxification. BNF revealed no ENA alterations for all concentrations and exposure lengths. In the NAP experiment a causal relationship between immature erythrocytes (IE) and ENA frequency disappearance was not found. BNF results with regard to IE frequency revealed an ability to alter the balance between erythropoiesis and removal of erythrocytes. Liver glutathione S-transferase activity was significantly induced after 2 and 48 h NAP exposure. A cortisol-impaired response seems to occur from 4 to 24 h NAP exposure, demonstrating an endocrine disruption. However, an adaptation process seems to occur after 48 h, since the plasma cortisol had a tendency to increase. The present findings confirm the usefulness of the adopted biomarkers. The ecological risk associated with aquatic contamination by NAP was also confirmed by the present data.
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Elovaara E, Väänänen V, Mikkola J. Simultaneous analysis of naphthols, phenanthrols, and 1-hydroxypyrene in urine as biomarkers of polycyclic aromatic hydrocarbon exposure: intraindividual variance in the urinary metabolite excretion profiles caused by intervention with beta-naphthoflavone induction in the rat. Arch Toxicol 2003; 77:183-93. [PMID: 12698233 DOI: 10.1007/s00204-003-0436-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2002] [Accepted: 12/05/2002] [Indexed: 11/28/2022]
Abstract
Two fluorimetric HPLC methods are described for the quantification of naphthols, phenanthrols and 1-hydroxypyrene (1-OHP) in urine specimens obtained from male Wistar rats exposed to naphthalene, phenanthrene and pyrene. The polycyclic aromatic hydrocarbons (PAHs) were given intraperitoneally, either alone (1.0 mmol/kg body weight) or as an equimolar mixture (0.33 mmol/kg), using the same dosages for repeated treatments on week 1 and week 2. Between these treatments, PAH-metabolizing activities encoded by aryl hydrocarbon (Ah) receptor-controlled genes were induced in the rats with beta-naphthoflavone (betaNF). Chromatographic separation of five phenanthrols (1-, 2-, 3-, 4-, and 9-isomers) was accomplished using two different RP C-18 columns. Despite selective detection (programmable wavelengths), the quantification limits in the urine ranged widely: 1-OHP (0.18 microg/l) <phenanthrols (0.34-0.45 microg/l) <2-naphthol (1.5 microg/l) <1-naphthol (4 micro g/l). The relative standard deviation of the methods was good, as also was the reproducibility. The molar fraction of the dose excreted in 24-h urine as naphthols (<or=4.0%), phenanthrols (<or=1.1%), and 1-OHP (<or=2.4%) was low. Urinary disposition increased differentially in betaNF-induced rats: naphthols, 9-phenanthrol (1- to-2-fold); 2-, 3-, and 4-phenanthrols (4- to 5-fold); 1-phenanthrol and 1-OHP (over 11-fold). The OH-metabolites were analyzed before and after enzymatic hydrolysis (beta-glucuronidase/arylsulfatase). The percentage excreted as a free phenol in urine varied for 1-OHP (2-11%), 1-naphthol (36-51%), 2-naphthol (59-65%), and the phenanthrols (29-94%). 1-Naphthyl- and 1-pyrenyl beta- d-glucuronide served as measures for the completeness of enzymatic hydrolysis. Characteristic differences observed in the urinary disposition of naphthalene, phenanthrene, and pyrene are described, as well as important factors (dose, metabolic capacity, relative urinary output) associated with biomarker validation. This intervention study clarifies intraindividual variation in PAH metabolism and provides useful information for the development of new methods applicable in the biomonitoring of PAH exposure in humans.
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Affiliation(s)
- Eivor Elovaara
- Laboratory of Toxicokinetics and Metabolism, Department of Industrial Hygiene and Toxicology, Finnish Institute of Occupational Health, 00250, Helsinki, Finland.
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20
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Pacheco M, Santos MA. Naphthalene and beta-naphthoflavone effects on Anguilla anguilla L. hepatic metabolism and erythrocytic nuclear abnormalities. ENVIRONMENT INTERNATIONAL 2002; 28:285-293. [PMID: 12220115 DOI: 10.1016/s0160-4120(02)00037-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effects of a polycyclic aromatic hydrocarbon (PAH) such as naphthalene (NAP)--an environmental contaminant--and beta-naphthoflavone (BNF)--a model substance (PAH-like compound)--were investigated in European eel (Anguilla anguilla L.) over 3-, 6-, and 9-day exposure (0.1-2.7 microM). Both xenobiotics revealed to be strong biotransformation (phase I) inducers. After 3-day exposure, liver ethoxyresorufin O-deethylase (EROD) activity was significantly increased by all NAP and BNF tested concentrations. At 6 and 9 days, liver EROD activity was significantly induced mainly by the highest NAP and BNF concentrations. Liver cytochrome P450 content was significantly induced after 3-day exposure to 0.9 and 2.7 microM BNF and 9-day exposure to 0.1, 0.3 and 0.9 microM NAP. Liver alanine transaminase (ALT) activity was measured as an indicator of hepatic health condition, revealing a significant decrease after 6-day exposure to 0.9 microM BNF. Genotoxicity measured as erythrocytic nuclear abnormalities (ENA) was detected in all BNF treated fish on day 6, whereas on day 9, ENA frequencies returned to control levels, significantly decreasing at 0.9 microM BNF exposure. Immature erythrocytes (IE) frequency demonstrated a decreasing tendency along the BNF experiment and concomitantly with the above ENA response. The present experimental results elect EROD activity in A. anguilla as a useful short- to medium-term biomarker of exposure to both PAH and PAH-like compounds. However, some problems can emerge in the presence of high xenobiotic concentrations. Concerning genotoxicity, it is hypothesized that ENA response depends on different factors such as the exhaustion of the detoxification process, the balance erythropoiesis/erythrocytic catabolism and the DNA repairing capacity.
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Affiliation(s)
- M Pacheco
- Department of Biology, University of Aveiro, Portugal.
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Shoda T, Mitsumori K, Onodera H, Toyoda K, Uneyama C, Takada K, Hirose M. Liver tumor-promoting effect of beta-naphthoflavone, a strong CYP 1A1/2 inducer, and the relationship between CYP 1A1/2 induction and Cx32 decrease in its hepatocarcinogenesis in the rat. Toxicol Pathol 2000; 28:540-7. [PMID: 10930040 DOI: 10.1177/019262330002800406] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Interrelationships among induction of cytochrome P-450 (CYP) 1A1/2, decrease in connexin 32 (Cx32), and liver tumor-promoting activity by beta-naphthoflavone (BNF) in the promotion stage were examined in a 2-stage liver carcinogenesis model. A total of 20 male Fischer 344 rats were initiated with a single intraperitoneal injection of 150 mg/kg of diethylnitrosamine (DEN) or were given the saline vehicle alone. Starting 2 weeks later, they were fed a diet containing 2%, 1%, or 0% BNF for 6 weeks. All animals were subjected to a two-thirds partial hepatectomy at week 3 and were sacrificed at week 8. Absolute and relative liver weights were significantly increased in the DEN+BNF groups as compared to the DEN-alone group. Diffuse hepatocellular hypertrophy with cytoplasmic eosinophilia, sometimes accompanied by development of adenoma-like hepatic foci, was observed in the BNF-treated rats. Remarkable induction of cytochrome CYP 1A1/2 and significant increase in CYP 2E1 were noted in the DEN+BNF groups, and positive immunohistochemical staining for both was observed diffusely. The areas of Cx32-positive spots per hepatocyte in the centrilobular areas of livers of the BNF-treated rats were significantly decreased, but no changes were observed in periportal areas. The numbers and areas of foci positive for glutathione S-transferase placental form were increased in the BNF-treated groups. These results suggest that BNF is a liver tumor promoter that, unlike phenobarbital, does not induce CYP 2B1/2 isozymes, and there seems to be no direct relationship between CYP 1A1/2 induction and Cx32 reduction in BNF hepatocarcinogenesis.
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Affiliation(s)
- T Shoda
- Division of Pathology, National Institute of Health Sciences, Tokyo, Japan
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Shoda T, Mitsumori K, Takahashi T, Horiuchi KI, Yamazaki Y, Suzuki Y, Katsuda Y, Yokomoto Y, Kurumi M. Liver Tumor Promotion by .BETA.-Naphthoflavone, a Strong CYP 1A1/2 Inducer, in a 28 Week Two-stage Rat Hepatocarcinogenesis Model Using Diethylnitrosamine as an Initiator. J Toxicol Pathol 2000. [DOI: 10.1293/tox.13.37] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Toshiyuki Shoda
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
- Section of Safety, Research Laboratories, Torii Pharmaceutical Co., Ltd. 1-2-1 Ohnodai, Midori-ku, Chiba-shi, Chiba 267-0056, Japan
| | - Kunitoshi Mitsumori
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Tadakazu Takahashi
- Section of Safety, Research Laboratories, Torii Pharmaceutical Co., Ltd. 1-2-1 Ohnodai, Midori-ku, Chiba-shi, Chiba 267-0056, Japan
| | - Ken-ichi Horiuchi
- Section of Safety, Research Laboratories, Torii Pharmaceutical Co., Ltd. 1-2-1 Ohnodai, Midori-ku, Chiba-shi, Chiba 267-0056, Japan
| | - Yuji Yamazaki
- Section of Safety, Research Laboratories, Torii Pharmaceutical Co., Ltd. 1-2-1 Ohnodai, Midori-ku, Chiba-shi, Chiba 267-0056, Japan
| | - Yusuke Suzuki
- Section of Safety, Research Laboratories, Torii Pharmaceutical Co., Ltd. 1-2-1 Ohnodai, Midori-ku, Chiba-shi, Chiba 267-0056, Japan
| | - Yoshiaki Katsuda
- Section of Safety, Research Laboratories, Torii Pharmaceutical Co., Ltd. 1-2-1 Ohnodai, Midori-ku, Chiba-shi, Chiba 267-0056, Japan
| | - Yasuki Yokomoto
- Section of Safety, Research Laboratories, Torii Pharmaceutical Co., Ltd. 1-2-1 Ohnodai, Midori-ku, Chiba-shi, Chiba 267-0056, Japan
| | - Masateru Kurumi
- Section of Safety, Research Laboratories, Torii Pharmaceutical Co., Ltd. 1-2-1 Ohnodai, Midori-ku, Chiba-shi, Chiba 267-0056, Japan
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Liu DY, Gorrod JW. Induction and inhibition of the in vitro N1-oxidation of 9-benzyladenine and isomeric 9-(nitrobenzyl)adenines. DRUG METABOLISM AND DRUG INTERACTIONS 1999; 15:141-57. [PMID: 10707120 DOI: 10.1515/dmdi.1999.15.2-3.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
The present study investigated some aspects of the enzymology of the in vitro N1-oxidation of 9-benzyladenine (BA) and isomeric 9-(nitrobenzyl)adenines (NBAs) using various potential inducers and inhibitors of cytochrome P-450 (CYP). When incubated with phenobarbital-induced rabbit hepatic microsomes, the N1-oxidation rates of BA and 9-(4-nitrobenzyl)adenine were about 6- and 2-fold higher than that of the control, respectively; while the N1-oxidation of 9-(2-nitrobenzyl)adenine and 9-(3-nitrobenzyl)adenine was not markedly affected. In contrast, beta-naphthoflavone and Arochlor 1254 showed no inductive effects towards the N1-oxidation of any of these substrates. Using 12 typical CYP inhibitors, it was found that nifedipine (CYP3A inhibitor) and haloperidol (CYP2D inhibitor) showed significant inhibition towards the N1-oxidation of BA and NBAs. Therefore, the N1-oxidation of BA and NBAs is probably catalysed by CYP3A and CYP2D subfamilies. Furthermore, when 9-(4-nitrobenzyl)adenine was incubated with compounds which possessed a certain chemical similarity to the adenine substrate, various degrees of inhibition of N1-oxidation of 9-(4-nitrobenzyl)adenine were observed. These observations allowed a preliminary indication as to the structure-metabolism relationship of 9-substituted adenine derivatives.
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Affiliation(s)
- D Y Liu
- Chelsea Department of Pharmacy, King's College London, University of London, UK
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Kashfi K, McDougall CJ, Dannenberg AJ. Comparative effects of omeprazole on xenobiotic metabolizing enzymes in the rat and human. Clin Pharmacol Ther 1995; 58:625-30. [PMID: 8529327 DOI: 10.1016/0009-9236(95)90018-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Omeprazole induces CYP1A in the human liver and gut, which has led to concern about possible side effects. The purpose of this study was to compare the effects of omeprazole on phase 1 and phase 2 enzymes in the rat and human. Male rats were treated with intraperitoneal (40 or 80 mg/kg) or oral omeprazole (40 mg/kg) for 5 or 14 days, respectively. The activities and amounts of CYP1A, uridine diphosphate-glucuronosyltransferase, and glutathione transferase were determined in liver and gut. Enzyme activities were also determined in duodenal biopsy specimens from six healthy human volunteers before and after treatment with omeprazole (20 mg/day) for 10 days. Treatment with intraperitoneal omeprazole (40 mg/kg; 80 mg/kg) coinduced uridine diphosphate-glucuronosyltransferase (36%; 66%), glutathione transferase (22%; 50%), and CYP1A (26%; 50%) in rat liver. In rat small intestine, comparable levels of induction were observed for uridine diphosphate-glucuronosyltransferase and glutathione transferase; CYP1A was unaffected. Oral omeprazole had similar effects. Immunoblotting showed corresponding changes in the amounts of these enzymes. Omeprazole increased the activities of CYP1A (19% to 167%; p = 0.014) and uridine diphosphate-glucuronosyltransferase (11% to 68%; p = 0.04) in the duodenal biopsy specimens of all six human volunteers; glutathione transferase was unaffected. Thus, omeprazole coinduced multiple xenobiotic metabolizing enzymes in the rat and human. The pattern of induction differed in the rat and human, consistent with known differences in genetic regulatory elements in the two species.
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Affiliation(s)
- K Kashfi
- Department of Medicine, New York Hospital-Cornell Medical Center, NY 10021, USA
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Gagné F, Blaise C. Evaluation of the genotoxicity of environmental contaminants in sediments to rainbow trout hepatocytes. ACTA ACUST UNITED AC 1995. [DOI: 10.1002/tox.2530100309] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Vikse R, Ingebrigtsen K, Klungsøyr L, Alexander J. Effects of enzyme induction on the distribution of the food carcinogen 2-amino-3,8-dimethyl-imidazo[4,5-ss]-quinoxaline (MeIQx) in Ah-receptor- responsive- and Ah-receptor-non-responsive mice. PHARMACOLOGY & TOXICOLOGY 1995; 77:57-64. [PMID: 8532613 DOI: 10.1111/j.1600-0773.1995.tb01914.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The distribution of the food carcinogen 2-amino-3,8-dimethyl-imidazo[4,5-ss]quinoxaline (MeIQx) was studied in Ah-responsive-(C57BL/6J) and Ah-non-responsive mice (DBA/2N). The time dependent organ distribution of radioactivity after 14C-MeIQx (10 mg/kg) administration in C57BL/6J showed that at day 4 most of the radioactivity had been excreted and that the remaining radioactivity was found in liver, kidneys, lungs and spleen. C57BL/6J bound more radioactivity in the kidneys than the DBA/2N strain whereas approximately the same amount was left in the liver and lungs in both strains 4 days after MeIQx exposure. Liver microsomes of the two strains had approximately the same ability to activate MeIQx in the Ames Salmonella assay. beta-Naphthoflavone treatment of the animals greatly increased microsomal activating capacity, but only in the C57BL/6J strain. Isosafrole treatment of the animals only slightly increased the activating capacity, but particularly with microsomes from the DBA/2N strain, displacement of the putative inhibitory isosafrole metabolite greatly increased their activating capacity. In the whole animals pretreatment with beta-naphthoflavone, which induces P450IA only in the C57BL/6J strain, did not significantly change the amount of retained radioactivity in any of the strains. Isosafrole induces only P450IA2, the major N2-hydroxylating enzyme of heterocyclic amines, in both strains. Such pretreatment reduced the amount retained in the kidney of both strains whereas it reduced the retained amount of radioactivity in the liver with about 60% only in the Ah-non-responsive strain (DBA/2N). The effect of isosafrole did not persist when MeIQx was given three days after the last injection.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Vikse
- Graduate Research Laboratory, Stabekk College, Bekkestua, Norway
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Ioannides C, Parke DV. Induction of cytochrome P4501 as an indicator of potential chemical carcinogenesis. Drug Metab Rev 1993; 25:485-501. [PMID: 8313839 DOI: 10.3109/03602539308993983] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- C Ioannides
- School of Biological Sciences, University of Surrey, UK
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Different inhibition and induction profiles of hepatic drug metabolism in rats and dogs by two structurally related pyridyl diazinone cardiotonic agents. Biochem Pharmacol 1991; 41:411-7. [PMID: 1994899 DOI: 10.1016/0006-2952(91)90538-g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
ICI 153,110 and ICI 170,777, two pyridyl diazinone cardiotonic agents, produced a different profile of effects on hepatic microsomal mixed function oxidase enzymes following multiple oral dosing to rats and dogs; these differences may be related to the molecular dimensions of the two molecules. ICI 153,110 significantly increased levels of total P450, ethoxycoumarin O-deethylase and ethoxyresorufin O-deethylase in rat microsomes, indicating an induction profile (P448) similar to that of beta-naphthoflavone. This was supported by gel electrophoresis (SDS-PAGE) of microsomal proteins; a similar type of induction was observed in dog microsomes. In contrast, ICI 170,777 produced no changes indicating enzyme induction in either rat or dog. Instead, ICI 170,777 appeared to inhibit specifically the activity of aldrin epoxidase in the rat. Inhibitory activity was also indicated in the rat by prolongation of pentobarbitone sleeping time following single oral doses of either ICI 153,110 or ICI 170,777. The time-course of this effect appeared to correlate more closely with the profile of circulating metabolites, although both parent compounds were found to produce type II spectral changes on interaction with control rat microsomes. The molecular dimensions (area/depth2) of the compounds supported the finding that only ICI 153,110 should interact with or induce P448 isozymes.
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