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Oleaga C, García M, Solé A, Ciudad CJ, Izquierdo-Pulido M, Noé V. CYP1A1 is overexpressed upon incubation of breast cancer cells with a polyphenolic cocoa extract. Eur J Nutr 2011; 51:465-76. [DOI: 10.1007/s00394-011-0231-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 07/18/2011] [Indexed: 10/17/2022]
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Ribonnet L, van der Heiden E, Nobels I, Chaumont A, Remacle AS, De Saeger S, Schneider YJ, Scippo ML, Blust R, Pussemier L, Larondelle Y. Potential of an in vitro toolbox combined with exposure data as a first step for the risk assessment of dietary chemical contaminants. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2011; 28:1136-58. [PMID: 21762035 DOI: 10.1080/19440049.2011.584069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In vitro risk assessment of dietary contaminants has become a priority in human food safety. This paper proposes an in vitro approach associating different complementary tools in an original toolbox and aims to improve the assessment of the toxicological impact of dietary contaminants at realistic human exposure levels, with a special focus on the intestinal compartment. The system is based on the use of four complementary cellular tools, namely stress gene induction in transgenic strains of Escherichia coli, modulation of the activity of key biotransformation enzymes (cytochrome P-450 (CYP) 1A1 and 3A4) in a human intestinal cell line, and activation of aryl hydrocarbon receptor (AhR) and oestrogenic receptor (ER)-dependent genes in agonistic and antagonistic assays with luciferase reporter cells. It was applied to four chosen model molecules: ochratoxin A (OTA) and deoxynivalenol (DON), two common food-borne mycotoxins, and imazalil (IMA) and benomyl (BEN), two fungicides widely occurring in foodstuffs. All these assays were performed at or around a realistic intestinal concentration, determined through a deterministic approach based on the calculation of a theoretical maximum daily intake (TMDI). Using the four model molecules, it is clearly highlighted that induction of CYP1A1 activity and inhibition of CYP3A4 activity occurred in Caco-2 cells at a realistic intestinal concentration of IMA. Furthermore, some bacterial stress genes were induced in a range of realistic concentrations, following exposure to DON and IMA. In addition, BEN clearly provoked an ER agonistic activity in a human oestrogen sensitive reporter cell line. All these results are in accordance with the literature, suggesting that the in vitro toolbox constitutes an interesting approach in order to obtain a first 'fingerprint' of dietary contaminants at realistic human exposure for further risk assessment.
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Affiliation(s)
- L Ribonnet
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 2/8 and 5/3, B-1348 Louvain-la-Neuve, Belgium
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Vrba J, Vrublova E, Modriansky M, Ulrichova J. Protopine and allocryptopine increase mRNA levels of cytochromes P450 1A in human hepatocytes and HepG2 cells independently of AhR. Toxicol Lett 2011; 203:135-41. [DOI: 10.1016/j.toxlet.2011.03.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 03/07/2011] [Accepted: 03/08/2011] [Indexed: 11/25/2022]
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T-2 toxin is a cytochrome P450 1A1 inducer and leads to MAPK/p38- but not aryl hydrocarbon receptor-dependent interleukin-8 secretion in the human intestinal epithelial cell line Caco-2. Toxicology 2011; 284:34-41. [DOI: 10.1016/j.tox.2011.03.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 03/20/2011] [Accepted: 03/21/2011] [Indexed: 11/22/2022]
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CYP1A1/1B1 and CYP2A6/2A13 activity is conserved in cultures of differentiated primary human tracheobronchial epithelial cells. Toxicol In Vitro 2011; 25:922-9. [DOI: 10.1016/j.tiv.2011.02.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 02/17/2011] [Accepted: 02/24/2011] [Indexed: 12/19/2022]
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Molecular mechanisms of cold-induced CYP1A activation in rat liver microsomes. J Physiol Biochem 2011; 67:499-510. [PMID: 21505853 DOI: 10.1007/s13105-011-0095-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 04/11/2011] [Indexed: 10/18/2022]
Abstract
Cytochrome P4501A (the CYP1A1 and CYP1A2 enzymes) is known to metabolize anthropogenic xenobiotics to carcinogenic and mutagenic compounds. CYP1A1 transcriptional activation is regulated via the aryl hydrocarbon receptor (AhR)-dependent signal transduction pathway. CYP1A2 activation may occur through the AhR-dependent or AhR-independent signal transduction pathways. We used male Wistar rats to explore possible mechanisms of CYP1A activation induced by exposure to cold and the effects of the protein-tyrosine kinase inhibitors genistein, herbimycin A, and geldanamycin on the properties of hepatic CYP1A1 and CYP1A2 proteins following exposure to cold and to classic CYP1A inducers. The molecular mechanisms of cold-induced CYP1A1 and CYP1A2 activation are different. The CYP1A2 activation apparently occurs at the post-transcriptional level. The CYP1A1 activation, whether caused by exposure to cold or by classic CYP1A inducers, is AhR-dependent and occurs at the transcriptional level. Protein tyrosine kinase inhibitors have no effect on benzo(a)pyrene-induced CYP1A expression but alter cold-induced CYP1A1 activity and the CYP1A1 mRNA level. Thus, treatment with herbimycin A or geldanamycin leads to an increase in CYP1A1 activity, while treatment with genistein increases CYP1A1 mRNA expression and decreases CYP1A2 activity. These data elucidate the molecular mechanisms of cold-induced CYP1A activation and the role of protein kinases in the regulation of CYP1A during exposure to cold. Our results can also help identify the differences between the molecular mechanisms underlying the effects of the classic CYP1A inducers and the effects of cooling.
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Induction of cytochromes P450 1A1 and 1A2 by tanshinones in human HepG2 hepatoma cell line. Toxicol Appl Pharmacol 2011; 252:18-27. [PMID: 21262253 DOI: 10.1016/j.taap.2011.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/12/2011] [Accepted: 01/17/2011] [Indexed: 12/31/2022]
Abstract
Diterpenoid tanshinones including tanshinone IIA (TIIA), cryptotanshinone (CTS), tanshinone I (TI) and dihydrotanshinone I (DHTI) are the major bioactive components from Danshen. The major aim of our present study was to investigate the induction potential of these four main components of tanshinones (TIIA, CTS, TI, and DHTI) on the expression of CYP1A1 and CYP1A2 in HepG2 cells. Our results showed that all of these four tanshinones caused a significant time- and concentration-dependent increase in the amount of CYP1A1/2 expression in HepG2 cells. These induction effects were further characterized through transcriptional regulation: the induction of CYP1A1/2 mRNA level by tanshinones was completely blocked by the transcription inhibitor actinomycin D; the expression of CYP1A1/2 heterogeneous nuclear RNA was induced by tanshinone treatment; and CYP1A1 mRNA stability was not influenced by these tanshinones. Interestingly, tanshinones plus B[a]P produced additive/synergistic effect on CYP1A1/2 induction. In addition, the tanshinone-induced CYP1A1/2 expression was abolished by the aryl hydrocarbon receptor (AhR) antagonist resveratrol, suggesting an AhR dependent transcription mechanism. In the reporter gene assay, while TI and DHTI significantly induced AhR-dependent luciferase activity, TIIA and CTS failed to induce this activity. Collectively, the tanshinones could induce CYP1A1 and CYP1A2 expression through transcriptional activation mechanism and exert differential effects on activating AhR in HepG2 cells. Our findings suggest that rational administration of tanshinones should be considered with respect to their effect on AhR and CYP1A1/2 expression.
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Lee J, Lee E, Kwon D, Lim Y, Oh S, Oh M, Hong E. Up-regulation of cancer-related genes in HepG2 cells by TCDD requires PRMT I and IV. Mol Cell Toxicol 2010. [DOI: 10.1007/s13273-010-0017-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Han EH, Kim HG, Im JH, Jeong TC, Jeong HG. Up-regulation of CYP1A1 by rutaecarpine is dependent on aryl hydrocarbon receptor and calcium. Toxicology 2009; 266:38-47. [PMID: 19853001 DOI: 10.1016/j.tox.2009.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 10/12/2009] [Accepted: 10/12/2009] [Indexed: 01/31/2023]
Abstract
Rutaecarpine is a quinazolinocarboline alkaloid isolated from a traditional Chinese medicinal fruit, Evodia rutaecarpa. In the present study, we investigated the effect of rutaecarpine on CYP1A1 expression mediated by [Ca(2+)] and the AhR pathway in mouse hepatoma Hepa-1c1c7 cells. Rutaecarpine also significantly increased CYP1A1 enzyme activity and mRNA and protein levels. Rutaecarpine markedly induced XRE and AhR binding activity. CH-223191, an AhR antagonist, blocked the rutaecarpine-induced CYP1A1 enzyme activity and mRNA and protein expression. In addition, rutaecarpine remarkably induced the phosphorylation of Ca(2+)/calmodulin (CaM)-dependent protein kinase (CaMK). W7 and BAPTA/AM, a CaM antagonist and an intracellular Ca(2+) chelator, respectively, blocked the rutaecarpine-induced CYP1A1 enzyme activity and mRNA and protein expression. These results indicate that rutaecarpine induces CYP1A1 expression through AhR- and calcium-dependent mechanisms.
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Affiliation(s)
- Eun Hee Han
- Department of Toxicology, College of Pharmacy, Chungnam National University, 220 Gung-dong, Yuseong-Gu, Daejeon 305-764, South Korea
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Skupinska K, Misiewicz-Krzeminska I, Lubelska K, Kasprzycka-Guttman T. The effect of isothiocyanates on CYP1A1 and CYP1A2 activities induced by polycyclic aromatic hydrocarbons in Mcf7 cells. Toxicol In Vitro 2009; 23:763-71. [PMID: 19362136 DOI: 10.1016/j.tiv.2009.04.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2008] [Revised: 03/31/2009] [Accepted: 04/01/2009] [Indexed: 12/13/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs)--environmental carcinogens--are metabolized by CYP1A1 and CYP1A2 enzymes to oxy-derivatives, which are able to bind to DNA and initiate carcinogenesis. PAHs induce CYP1A1 and CYP1A2 activity, which increases the risk of development of carcinogenesis. Isothiocyanates (ITCs), naturally occurring in Brassica vegetables, possess chemopreventive properties and are able to reduce the CYP1A enzyme activity. In this paper we report our study of the ability of ITCs: sulforaphane and its analogues: isothiocyanate-2-oxohexyl and alyssin, to inhibit CYP1A1 and CYP1A2 enzyme activity induced by the PAHs, anthracene (ANT) and dibenzo[a,h]anthracene (DBA) in human breast cancer cell line Mcf7. The aim was to determine whether the differences in structure of ITCs change their inhibitory properties, and whether these properties depend on the type of inducer. The results indicate that the properties of ITCs depend on the type of PAH: ITCs are more potent in inhibiting activity induced by the weaker inducer. It was also found that the change in ITCs' structure influences their activities. ITC 2-oxohexyl was the weakest inhibitor, whereas sulforaphane and alyssin exhibited similar potency. The study revealed that inhibition of CYP1A1 activity is direct whereas inhibition of CYP1A2 activity is not only direct but is also caused by the level of protein disturbance.
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Matsumura F. The significance of the nongenomic pathway in mediating inflammatory signaling of the dioxin-activated Ah receptor to cause toxic effects. Biochem Pharmacol 2009; 77:608-26. [DOI: 10.1016/j.bcp.2008.10.013] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 09/26/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022]
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62
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Aung HH, Vasu VT, Valacchi G, Corbacho AM, Kota RS, Lim Y, Obermueller-Jevic UC, Packer L, Cross CE, Gohil K. Effects of dietary carotenoids on mouse lung genomic profiles and their modulatory effects on short-term cigarette smoke exposures. GENES AND NUTRITION 2008; 4:23-39. [PMID: 19104882 PMCID: PMC2654053 DOI: 10.1007/s12263-008-0108-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 12/01/2008] [Indexed: 02/08/2023]
Abstract
Male C57BL/6 mice were fed diets supplemented with either beta-carotene (BC) or lycopene (LY) that were formulated for human consumption. Four weeks of dietary supplementations results in plasma and lung carotenoid (CAR) concentrations that approximated the levels detected in humans. Bioactivity of the CARs was determined by assaying their effects on the activity of the lung transcriptome (~8,500 mRNAs). Both CARs activated the cytochrome P450 1A1 gene but only BC induced the retinol dehydrogenase gene. The contrasting effects of the two CARs on the lung transcriptome were further uncovered in mice exposed to cigarette smoke (CS) for 3 days; only LY activated ~50 genes detected in the lungs of CS-exposed mice. These genes encoded inflammatory-immune proteins. Our data suggest that mice offer a viable in vivo model for studying bioactivities of dietary CARs and their modulatory effects on lung genomic expression in both health and after exposure to CS toxicants.
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Affiliation(s)
- Hnin H Aung
- Center for Comparative Respiratory Biology and Medicine, Clinical Nutrition and Vascular Medicine, Genome and Biomedical Sciences Facility, University of California, 6404A, 451 East Health Sciences Drive, Davis, CA, 95616, USA
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Arukwe A, Nordbø B. Hepatic biotransformation responses in Atlantic salmon exposed to retinoic acids and 3,3',4,4'-tetrachlorobiphenyl (PCB congener 77). Comp Biochem Physiol C Toxicol Pharmacol 2008; 147:470-82. [PMID: 18373956 DOI: 10.1016/j.cbpc.2008.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 02/07/2008] [Accepted: 02/09/2008] [Indexed: 01/15/2023]
Abstract
Active derivatives of vitamin A are essential in physiological processes such as cell growth, differentiation, morphogenesis and development. The biological functions of vitamin A are mediated through the retinoid acid receptors (RARs) and retinoid X receptors (RXRs). Aryl hydrocarbon receptor (AhR) agonists such as planar halogenated compounds are known to interfere with vitamin A homeostasis in both field and laboratory studies. In this study, we have investigated the molecular interactions between vitamin A and AhR signalling pathways using juvenile Atlantic salmon and agonists for both receptor pathways. Groups of juvenile salmon were treated with all-trans- and 9-cis-retinoic acid mixture (7:3 ratio) dissolved in DMSO (dimethyl sulfoxide) at 0.1, 1 and 10 mg/kg fish weight. The mixture was force fed singly or in combination with 0.1 mg 3,3',4,4'-tetrachlorobiphenyl (co-planar congener 77)/kg fish weight dissolved in DMSO. Liver samples were collected 3 days after PCB-77 exposure. A separate group exposed to combined retinoic acid (1 mg/kg for 5 days) and PCB-77, was sampled at 3, 7 and 14 days after PCB-77 exposure. Liver samples collected from all exposure groups were analyzed for gene (RARalpha, AhR2alpha, AhR2beta, CYP1A1, UGT1 and GSTpi) expression using real-time PCR and activity (7-ethoxyresorufin O-deethylase (EROD), UGT and GST) using biochemical methods with specific substrates. Our data showed that exposure to RA alone did not produce a significant increase of RARalpha mRNA levels, and the presence of PCB-77 attenuated the expression of RARalpha in RA dose- and time-specific manner. In addition, RA produced a dose-dependent increase of CYP1A1 mRNA and activity (EROD) levels without concomitant increase in AhR2 isoforms. When administered alone, PCB-77 produced increased CYP1A1, UGT1 and GSTpi mRNA and enzyme levels. The PCB-77-induced CYP1A1, UGT1 and GSTpi (mRNA and activity) levels were modulated by RA, in a parameter and dose-specific manner. In general, our data show an interaction between vitamin A and AhR signalling that may affect retinoid homeostasis in fish.
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Affiliation(s)
- Augustine Arukwe
- Department of Biology, Norwegian University of Science and Technology (NTNU), Høyskoleringen 5, 7491 Trondheim, Norway.
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Alonso M, Casado S, Miranda C, Tarazona JV, Navas JM, Herradón B. Decabromobiphenyl (PBB-209) activates the aryl hydrocarbon receptor while decachlorobiphenyl (PCB-209) is inactive: experimental evidence and computational rationalization of the different behavior of some halogenated biphenyls. Chem Res Toxicol 2008; 21:643-58. [PMID: 18311929 DOI: 10.1021/tx700362u] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In rat H4IIE cells permanently transfected with a luciferase gene under the control of AhR, incubation with PBB-209 led to a statistically significant increase of luminescence. In this system, PCB-209 only caused a small induction of luciferase activity. In a fish cell line, only PBB-209 was able to provoke an induction of ethoxyresorufin- O-deethylase activity. Ligand binding to the AhR was studied by means of a cell-free in vitro system in which the activation of AhR is very unlikely to occur without ligand binding. None of the biphenyls studied provoked any activation of AhR in this system. To rationalize the results and to get insight into the molecular mechanism of activation of AhR by PBB-209 as compared with PCB-209, a comprehensive computational study was carried out on these congeners as well as on PCB-126 and PCB-169, two potent AhR activators through ligand binding. The calculations include (i) conformational analysis and dipole moments of each conformer, (ii) aromaticity indices, (iii) molecular electrostatic potentials, (iv) quadrupole moments, (v) electronic and reactivity descriptors, and (vi) dissociation energies of C-Cl and C-Br bonds in model aromatic compounds. It was found that some molecular features of PBB-209, such as the electrostatic potential (EP) and EP-derived descriptors (Politzer's parameters), indicate that PBB-209 is more similar to PCB-126 and PCB-169 than to PCB-209, which share quite similar geometries based on the substitution pattern. The similarity between PBB-209, PCB-126, and PCB-169 seems to hint that these three compounds can share, at least partially, similar mechanisms of activation of AhR. It is unquestionable that PCB-126 and PCB-169 directly bind AhR and PBB-209 does not. We hypothesize that there are several simultaneous mechanisms for activation of AhR, and the most active compounds act for more than one mechanism.
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Affiliation(s)
- Mercedes Alonso
- Instituto de Química Orgánica General, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
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Degner SC, Kemp MQ, Hockings JK, Romagnolo DF. Cyclooxygenase-2 Promoter Activation by the Aromatic Hydrocarbon Receptor in Breast Cancer MCF-7 Cells: Repressive Effects of Conjugated Linoleic Acid. Nutr Cancer 2007; 59:248-57. [DOI: 10.1080/01635580701485585] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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66
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Kumar A, Upadhyay G, Modi DR, Singh MP. The involvement of secondary signaling molecules in cytochrome P-450 1A1-mediated inducible nitric oxide synthase expression in benzo(a)pyrene-treated rat polymorphonuclear leukocytes. Life Sci 2007; 81:1575-84. [DOI: 10.1016/j.lfs.2007.09.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 09/14/2007] [Accepted: 09/18/2007] [Indexed: 11/24/2022]
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Jos A, Segner H, Herradón B, Repetto G, Navas JM. Induction of EROD activity by 1-phenylimidazole and β-naphthoflavone in rainbow trout cultured hepatocytes: A comparative study. Toxicol In Vitro 2007; 21:1307-10. [PMID: 17521864 DOI: 10.1016/j.tiv.2007.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2006] [Revised: 02/22/2007] [Accepted: 03/25/2007] [Indexed: 11/30/2022]
Abstract
The classical pathway for induction of cytochrome P4501A (CYP1A) by xenobiotics is ligand binding to the aryl hydrocarbon receptor (AhR). However, several studies with mammalian cell systems point out a range of xenobiotics including imidazole derivatives, which are able to activate CYP1A through non-classical mechanisms. The objective of the present work is to compare induction of CYP1A (determined at the catalytic level as 7-ethoxyresorufin-O-deethylase, EROD) in rainbow trout (Oncorhynchus mykiss) hepatocytes by the prototypic AhR ligand, beta-naphthoflavone (betaNF), and by the imidazole derivative, 1-phenylimidazole (PIM). PIM was able to induce EROD activity although its potency was clearly lower than that of betaNF. In order to assess the relative importance of classical AhR ligand binding and alternative signaling pathways in CYP1A induction by PIM, co-exposure experiments with the partial AhR antagonist alpha-naphthoflavone (alphaNF) or with inhibitors of protein kinase C (staurosporine) and tyrosine kinases (genistein, herbimicine) were performed. alphaNF and herbimicin provoked a decrease of EROD induction both by betaNF and PIM, whereas staurosporine and genistein remained without effect. The overall similarities in the response of betaNF and PIM to the various inhibitors suggest that both compounds, in apparent contrast to the behaviour of some other imidazole derivatives, induce CYP1A following similar mechanisms.
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Affiliation(s)
- A Jos
- Area of Toxicology, Faculty of Pharmacy, University of Seville, Professor García González 2, E-41012 Seville, Spain
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Gaube F, Wolfl S, Pusch L, Kroll TC, Hamburger M. Gene expression profiling reveals effects of Cimicifuga racemosa (L.) NUTT. (black cohosh) on the estrogen receptor positive human breast cancer cell line MCF-7. BMC Pharmacol 2007; 7:11. [PMID: 17880733 PMCID: PMC2194763 DOI: 10.1186/1471-2210-7-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 09/20/2007] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Extracts from the rhizome of Cimicifuga racemosa (black cohosh) are increasingly popular as herbal alternative to hormone replacement therapy (HRT) for the alleviation of postmenopausal disorders. However, the molecular mode of action and the active principles are presently not clear. Previously published data have been largely contradictory. We, therefore, investigated the effects of a lipophilic black cohosh rhizome extract and cycloartane-type triterpenoids on the estrogen receptor positive human breast cancer cell line MCF-7. RESULTS Both extract and purified compounds clearly inhibited cellular proliferation. Gene expression profiling with the extract allowed us to identify 431 regulated genes with high significance. The extract induced expression pattern differed from those of 17beta-estradiol or the estrogen receptor antagonist tamoxifen. We observed a significant enrichment of genes in an anti-proliferative and apoptosis-sensitizing manner, as well as an increase of mRNAs coding for gene products involved in several stress response pathways. These functional groups were highly overrepresented among all regulated genes. Also several transcripts coding for oxidoreductases were induced, as for example the cytochrome P450 family members 1A1 and 1B1. In addition, some transcripts associated with antitumor but also tumor-promoting activity were regulated. Real-Time RT-PCR analysis of 13 selected genes was conducted after treatment with purified compounds - the cycloartane-type triterpene glycoside actein and triterpene aglycons - showing similar expression levels compared to the extract. CONCLUSION No estrogenic but antiproliferative and proapoptotic gene expression was shown for black cohosh in MCF-7 cells at the transcriptional level. The effects may be results of the activation of different pathways. The cycloartane glycosides and - for the first time - their aglycons could be identified as an active principle in black cohosh.
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Affiliation(s)
- Friedemann Gaube
- Institute of Pharmacy, Department of Pharmaceutical Biology, University of Jena, Semmelweisstr. 10, 07743 Jena, Germany
| | - Stefan Wolfl
- Clinic of Internal Medicine II, University of Jena, Erlanger Allee 101, 07747 Jena, Germany
- Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Im Neuenheimerfeld 364, 69120 Heidelberg, Germany
| | - Larissa Pusch
- Clinic of Internal Medicine II, University of Jena, Erlanger Allee 101, 07747 Jena, Germany
| | - Torsten C Kroll
- Clinic of Internal Medicine II, University of Jena, Erlanger Allee 101, 07747 Jena, Germany
| | - Matthias Hamburger
- Institute of Pharmacy, Department of Pharmaceutical Biology, University of Jena, Semmelweisstr. 10, 07743 Jena, Germany
- Department of Pharmaceutical Sciences, Institute of Pharmaceutical Biology, University of Basel, Klingelbergstr. 50, CH-4053 Basel, Switzerland
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Sugihara K, Okayama T, Kitamura S, Yamashita K, Yasuda M, Miyairi S, Minobe Y, Ohta S. Comparative study of aryl hydrocarbon receptor ligand activities of six chemicals in vitro and in vivo. Arch Toxicol 2007; 82:5-11. [PMID: 17899013 DOI: 10.1007/s00204-007-0232-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Accepted: 07/27/2007] [Indexed: 11/24/2022]
Abstract
The aryl hydrocarbon receptor (AhR) ligand activities of six known AhR ligands were compared in vivo and in vitro. The in vivo ligand activity was estimated in terms of induction of cytochrome P450 1A1/2 activities, i.e., ethoxyresorufin-O-dealkylase (EROD) and methoxyresorufin-O-dealkylase (MROD) activities, and in vitro ligand activity was evaluated with a recombinant yeast reporter gene assay. The test chemicals were 3-methylcholanthrene (MC), beta-naphthoflavone (beta-NF), indirubin, indigo, 3,3'-diindolylmethane (DIM) and diphenyl-p-phenylenediamine (DPPD). The first four showed potent AhR ligand activity in vitro, comparable with that of 2,3,7,8-tetrachlorodibenzo-p-dioxin, while DIM and DPPD showed weaker activity. Administration of MC and beta-NF to mice caused significant induction of EROD and MROD activities, while indirubin, indigo and DIM also induced these activities, but less potently. DPPD also induced the activities, but was toxic at higher doses. These enhancing effects were lost or greatly reduced in Ahr-null mice (Ahr (-/-)). Our results suggest that EROD and MROD activity assays are useful for evaluating the AhR ligand activity of chemicals in vivo, where the biodynamics of the chemicals plays an important role.
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Affiliation(s)
- Kazumi Sugihara
- Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
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Ito S, Chen C, Satoh J, Yim S, Gonzalez FJ. Dietary phytochemicals regulate whole-body CYP1A1 expression through an arylhydrocarbon receptor nuclear translocator-dependent system in gut. J Clin Invest 2007; 117:1940-50. [PMID: 17607366 PMCID: PMC1890999 DOI: 10.1172/jci31647] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 04/24/2007] [Indexed: 12/20/2022] Open
Abstract
Cytochrome P450 1A1 (CYP1A1) is one of the most important detoxification enzymes due to its broad substrate specificity and wide distribution throughout the body. On the other hand, CYP1A1 can also produce highly carcinogenic intermediate metabolites through oxidation of polycyclic aromatic hydrocarbons. We describe what we believe to be a novel regulatory system for whole-body CYP1A1 expression by a factor originating in the gut. A mutant mouse was generated in which the arylhydrocarbon receptor nuclear translocator (Arnt) gene is disrupted predominantly in the gut epithelium. Surprisingly, CYP1A1 mRNA expression and enzymatic activities were markedly elevated in almost all non-gut tissues in this mouse line. The induction was even observed in early-stage embryos in pregnant mutant females. Interestingly, the upregulation was CYP1A1 selective and lost upon administration of a synthetic purified diet. Moreover, the increase was recovered by addition of the natural phytochemical indole-3-carbinol to the purified diet. These results suggest that an Arnt-dependent pathway in gut has an important role in regulation of the metabolism of dietary CYP1A1 inducers and whole-body CYP1A1 expression. This machinery might be involved in naturally occurring carcinogenic processes and/or other numerous biological responses mediated by CYP1A1 activity.
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Affiliation(s)
- Shinji Ito
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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71
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Xu M, Li D, Lu Y, Chen GQ. Leukemogenic AML1-ETO fusion protein increases carcinogen-DNA adduct formation with upregulated expression of cytochrome P450-1A1 gene. Exp Hematol 2007; 35:1249-55. [PMID: 17560011 DOI: 10.1016/j.exphem.2007.04.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 03/26/2007] [Accepted: 04/20/2007] [Indexed: 11/28/2022]
Abstract
OBJECTIVE AML1-ETO fusion protein is a product of chromosome translocation t(8;21) frequently occurred in acute myeloid leukemia (AML), but its sole expression appears to fail to cause overt leukemia in vivo. In this study, we investigated whether AML1-ETO expression impinged on action of chemical carcinogens-DNA adduct formation. MATERIALS AND METHODS AML1-ETO fusion protein was conditionally induced in engineered U937-A/E 9/14/18 cells. The formation of polycyclic aromatic hydrocarbon (PAH)-DNA adducts and the expression of PAH-metabolizing enzymes cytochrome P450 (CYP) 1A1 and arylhydrocarbon receptor (AhR) were detected by Western blot and/or quantitative RT-PCR. Luciferase reporter system was used to detect the regulation of AML1-ETO on CYP1A1 transcription. RESULTS Our results showed that AML1-ETO induction significantly increased the formation of carcinogen benzopyrene-DNA adducts in leukemic cells. In line with the effect, we also found that AML1-ETO induction upregulated CYP1A1 expression, which was dependent on AML1-binding motif in the promotor of CYP1A1 gene. Additionally, AML1-ETO protein also increased AhR expression, a ligand-activated transcription factor that mediates PAHs-induced CYP1A1 gene expression. CONCLUSION These data, combined with its inhibitory effect on DNA repair as reported previously, propose that the presence of AML1-ETO increases the susceptibility of cells to chemical carcinogens, which favors the development of additional genetic alterations.
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Affiliation(s)
- Min Xu
- Institute of Health Science, Shanghai Jiao-Tong University School of Medicine/Shanghai Institutes of Biological Sciences and School of Graduate, Chinese Academy of Sciences, Shanghai, China
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72
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Andersson C, Katsiadaki I, Lundstedt-Enkel K, Orberg J. Effects of 17alpha-ethynylestradiol on EROD activity, spiggin and vitellogenin in three-spined stickleback (Gasterosteus aculeatus). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2007; 83:33-42. [PMID: 17445917 DOI: 10.1016/j.aquatox.2007.03.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 03/12/2007] [Accepted: 03/15/2007] [Indexed: 05/15/2023]
Abstract
The three-spined stickleback (Gasterosteus aculeatus) has quantifiable biomarkers of exposure to estrogens (vitellogenin), androgens (spiggin) and aryl hydrocarbon receptor (AhR) agonists (EROD activity) and is therefore a promising test species for biomonitoring of reprotoxic chemicals in aquatic environments. In this study we evaluated the effects of 17alpha-ethynylestradiol (EE(2)) on EROD activity, induction of vitellogenin and spiggin, hepatosomatic index (HSI), ovarian somatic index (OSI) and nephrosomatic index (NSI). Adult male and female three-spined sticklebacks were exposed to concentrations of 0-170 ng EE(2)/l (measured concentrations) in a flow-through system for 21 days. Exposure to 170 ng EE(2)/l resulted in a significant 8- and 9-fold induction of gill EROD activity in males and females, respectively. In livers, EROD activity expressed in relation to microsomal protein content was suppressed due to a significant increase in microsomal protein content. Hepatic EROD activity per se expressed as picomol/min was not affected by exposure to EE(2). The lowest observed effect concentration for induction of vitellogenin in males was 53.7 ng EE(2)/l. In females, vitellogenin levels were significantly higher in those exposed to 170 ng EE(2)/l compared to controls. Spiggin production was significantly inhibited and NSI lower in males exposed to 170 ng EE(2)/l. In both females and males LSI was significantly higher in fish exposed to 170 ng EE(2)/l than in controls. In females exposed to 170 ng EE(2)/l, OSI was significantly lower and NSI higher than controls. The observed results from this study show that a synthetic estrogen can affect the well-known biomarker of exposure for dioxin-like compounds, EROD activity, and further that this response can differ between tissues. These findings are important for interpretation of biomonitoring data.
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Affiliation(s)
- Carin Andersson
- Department of Environmental Toxicology, Uppsala University, Norbyvägen 18A, SE-75236 Uppsala, Sweden.
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73
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Fang XK, Huang DF, Wang ZX, Wan CL, Sun T, Xu WJ, Liu CY, Zhou P, Qiao ZD. Identification of the proteins related to cytochrome P450 induced by fenvalerate in a Trichoplusia ni cell line. Cell Biol Toxicol 2007; 23:445-57. [PMID: 17484068 DOI: 10.1007/s10565-007-9006-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Accepted: 03/07/2007] [Indexed: 10/23/2022]
Abstract
In order to reveal the metabolic reaction to the presence of fenvalerate mediated by P450 in insects, we used the trypan blue exclusion technique and 3-(4,5-dimethylthiazol)-2,5-diphenyltrazolium bromide (MTT) reduction assay to assess the vitality of Trichoplusia ni (Tn) cells treated with fenvalerate, and observed dose- and time-dependent changes in total cellular P450s. In addition, two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) were used to identify the proteins involved in the fenvalerate reaction process. Finally, the cDNA of P450 fragments was cloned and real-time RT-PCR was performed. Our data showed that at the 0-15 mumol/L challenge concentration of fenvalerate, at which the vitality of Tn cells was not affected (p > 0.05), there was a tendency toward a dose- and time-response of total cellular P450s, which peaked at the 9 h (p < 0.05) and 12 h (p < 0.01) time points following 12.5 mumol/L stimulation with fenvalerate. The 2-DE assay detected more than 1300 protein spots in each two-dimensional gel, of which 33 spots displayed significant differences. Among the changed spots, three isoforms of P450 were identified. One of the three P450 cDNA fragments (CYP4L4) was cloned and sequenced, and its expression in treated Tn cells increased significantly (p < 0.01). It was found that fenvalerate induced the expression of P450s in insect cells. This suggests that fenvalerate could be metabolized by CYP4L4 through a hydroxylation reaction in insect cells.
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Affiliation(s)
- Xin-Kui Fang
- School of Agriculture and Biology, Shanghai Jiaotong University, 800 Dongchuan Road, 200240 Shanghai, PR China
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74
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Dávila-Borja VM, Belmont JA, Espinosa JJ, Moreno-Sánchez R, Albores A, Montero RD. Induction of CYP1A1 and CYP2E1 in rat liver by histamine: binding and kinetic studies. Arch Toxicol 2007; 81:697-709. [PMID: 17431589 DOI: 10.1007/s00204-007-0202-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 03/12/2007] [Indexed: 10/23/2022]
Abstract
Histamine (HA) may bind to cytochrome P450 (CYP450) in rat liver microsomes. The CYP450-HA complex seems to regulate some cellular processes such as proliferation. In the present work, it is shown that HA increases the activity and protein level of CYP1A1 and CYP2E1, in vivo. CYP1A1 is associated with polycyclic aromatic hydrocarbon-mediated carcinogenesis and CYP2E1 with liver damage by oxidative stress. Studies of enzyme kinetics and binding with rat liver microsomes and supersomes were carried out to determine whether HA is a substrate of CYP1A1 and/or CYP2E1. The lack of NADPH oxidation in the presence of HA showed that it is not a substrate for CYP1A1. Activity measurements using the O-dealkylation of ethoxyresorufin indicated that HA is a mixed-type inhibitor of CYP1A1 in both microsomes and supersomes. On the other hand, HA induced a significant NADPH oxidation catalyzed by CYP2E1 supersomes, strongly suggesting that HA is a substrate for this isoform. Furthermore, HA is consumed in the presence of CYP2E1-induced microsomes and supersomes, as determined by o-phtalaldehyde complexes with HA by HPLC. The present findings may contribute to understand better the physiological function of CYP450 in relation with inflammation and other physiological processes in which HA may have a relevant role.
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Affiliation(s)
- Víctor M Dávila-Borja
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, P.O. Box 70228, Mexico, DF 04510, Mexico
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75
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Park S, Dong B, Matsumura F. Rapid activation of c-Src kinase by dioxin is mediated by the Cdc37-HSP90 complex as part of Ah receptor signaling in MCF10A cells. Biochemistry 2007; 46:899-908. [PMID: 17223712 DOI: 10.1021/bi061925f] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the mechanism by which activation of the Ah receptor by dioxin (TCDD) was accompanied by rapid activation of c-Src kinase activity. A Western blotting analysis showed that such action of TCDD in MCF10A cells could effectively be suppressed by treatment with a specific inhibitor of Src family kinase, PP-2, as judged by Western blot detection of the active form of Src protein, indicating that Src kinase is directly activated by TCDD. Such an event, occurring within 10-30 min of the addition of TCDD, is also accompanied by simultaneous translocation of both Src and cdc37 proteins from cytosol into the 100,000 x g membrane fraction containing the plasma membrane. By dissociating the cytosolic Src-cdc37-HSP90 complex with 17 nM geldanamycin, an optimum concentration for affecting this cytosolic cdc37 complex, but not the cytosolic Ah receptor complex, we could show that the action of TCDD in activating c-Src and cdc37 was abolished, but not its action on CYP1A1. The important role of cdc37 in the action of TCDD-induced activation of c-Src was also confirmed by blocking cdc37 gene translation with the antisense oligonucleotide treatment as well as the siRNA preparation designed to silence cdc37 expression. To understand the functional meaning of the disruption of the Src-cdc37-HSP90 complex by 17 nM geldanamycin at the cellular level, we investigated its effect on TCDD-induced anti-apoptotic action. The results showed that geldanamycin at this concentration could also abolish this cellular effect of TCDD. Interestingly, such a role of cdc37 in mediating the action of TCDD appears to be limited to activation of c-Src kinase, but not kinases associated with activation of NFkB, C/EBPalpha, or ERK. Together, these observations support the hypothesis that there is a specific coordination between the activation of the cytosolic Ah receptor and the c-Src- and cdc37-containing HSP90 complex.
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Affiliation(s)
- Sujin Park
- Department of Environmental Toxicology, University of California, 1 Shields Avenue, Davis, California 95616, USA
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76
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Hu W, Sorrentino C, Denison MS, Kolaja K, Fielden MR. Induction of Cyp1a1 Is a Nonspecific Biomarker of Aryl Hydrocarbon Receptor Activation: Results of Large Scale Screening of Pharmaceuticals and Toxicants in Vivo and in Vitro. Mol Pharmacol 2007; 71:1475-86. [PMID: 17327465 DOI: 10.1124/mol.106.032748] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Expression of Cyp1a1 and its related enzyme activity have long been used as a biomarker for aryl hydrocarbon receptor (AhR) activation and a warning of dioxin-like toxicity. As a result, induction of Cyp1a1 by pharmaceutical drug candidates or environmental contaminants raises significant concern in risk assessment. The current study evaluates the specificity of Cyp1a1 induction as a marker for AhR affinity and activation and provides context to assess the relevancy of AhR activation to risk assessment. In vivo experiments examined the expression of Cyp1a1 and other AhR-regulated genes in liver, kidney, and heart in response to 596 compounds. From this data set, a subset of 147 compounds was then evaluated for their ability to activate or bind to the AhR using a combination of gel shift, reporter gene, and competitive receptor binding assays. Whereas in vivo Cyp1a1 mRNA expression is a sensitive marker for AhR activation, it lacks specificity, because 81 (59%) of 137 compounds were found to significantly induce Cyp1a1 in vivo but were not verified to bind or activate the AhR in vitro. Combining in vivo and in vitro findings, we identified nine AhR agonists, six of which are marketed therapeutics and have been approved by the U.S. Food and Drug Administration, including leflunomide, flutamide, and nimodipine. These drugs do not produce dioxin-like toxicity in rats or in humans. These data demonstrate that induction of Cyp1a1 is a nonspecific biomarker of direct AhR affinity and activation and lend further support to the hypothesis that Cyp1a1 induction and/or AhR activation is not synonymous with dioxin-like toxicity.
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Affiliation(s)
- Wenyue Hu
- Iconix Biosciences, Inc., 325 E. Middlefield Road, Mountain View, CA 94043, USA
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77
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Perepechaeva ML, Sidorova YA, Grishanova AY. Effect of cold stress on expression of genes for the AhR-dependent pathway of CYP1 regulation in rat liver. Bull Exp Biol Med 2006; 141:315-8. [PMID: 17073148 DOI: 10.1007/s10517-006-0159-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The level of mRNA for cytochromes P450 (CYP1A1, CYP1A2, and CYP1B1) and CYP1 regulatory proteins (heat shock protein, aryl hydrocarbon receptor, aryl hydrocarbon receptor repressor, and aryl hydrocarbon receptor nuclear translocator) was measured in the liver of rats after cold stress (4 degrees C). The CYP1A1 mRNA level increased and remained high for 10 days after 5-day cold exposure. The level of mRNA for CYP1A2, heat shock protein, and aryl hydrocarbon receptor nuclear translocator decreased by the 10th day. The level of mRNA for CYP1B1, aryl hydrocarbon receptor, and aryl hydrocarbon receptor nuclear translocator remained unchanged over this period.
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Affiliation(s)
- M L Perepechaeva
- Laboratory for Biochemistry of Foreign Compounds, Institute of Molecular Biology and Biophysics, Siberian Division of the Russian Academy of Medical Sciences, Novosibirsk
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78
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Sagredo C, Øvrebø S, Haugen A, Fujii-Kuriyama Y, Baera R, Botnen IV, Mollerup S. Quantitative analysis of benzo[a]pyrene biotransformation and adduct formation in Ahr knockout mice. Toxicol Lett 2006; 167:173-82. [PMID: 17049425 DOI: 10.1016/j.toxlet.2006.09.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 09/14/2006] [Accepted: 09/15/2006] [Indexed: 10/24/2022]
Abstract
Benzo[a]pyrene (BP) is an ubiquitous environmental pollutant with potent mutagenic and carcinogenic properties. The Ah receptor (Ahr) is involved in the metabolic activation of BP and is therefore important in the induction of chemical carcinogenesis. In this study, the relationship between Ahr genotype and biotransformation of BP in internal organs was investigated in Ahr (+/+), Ahr (+/-) and Ahr (-/-) mice. The mice were treated with BP (100mg/kg) by gavage. Gene expression was measured after 24h by real-time RT-PCR and showed induction of Cyp1a1 in liver and lung, and Cyp1b1 in lung in both Ahr (+/+) and Ahr (+/-). No induction of the Cyp genes was observed in the Ahr (-/-). There was a significant basal expression of Cyp1b1 in the liver of all genotypes, and this expression was independent of the BP exposure. Analyzed by HPLC-fluorescence, there were increased levels of protein and DNA adducts, metabolites, conjugates and unmetabolized BP in the internal organs of Ahr (-/-) as compared to Ahr (+/+) and Ahr (+/-) mice. This may be partly explained by a delayed bioactivation of BP in the Ahr deficient mice. The BP metabolism observed in the Ahr (-/-) mice is also evidence of an Ahr independent biotransformation of BP.
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Affiliation(s)
- Carlos Sagredo
- Section for Toxicology, National Institute of Occupational Health, P.O. Box 8149 Dep., N-0033 Oslo, Norway
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79
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Cho CW, Kim CW. Toxicoproteomics in the study of aromatic hydrocarbon toxicity. BIOTECHNOL BIOPROC E 2006. [DOI: 10.1007/bf02932029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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80
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Chan NLS, Wang H, Wang Y, Leung HY, Leung LK. Polycyclic aromatic hydrocarbon-induced CYP1B1 activity is suppressed by perillyl alcohol in MCF-7 cells. Toxicol Appl Pharmacol 2006; 213:98-104. [PMID: 16307765 DOI: 10.1016/j.taap.2005.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Revised: 09/28/2005] [Accepted: 10/07/2005] [Indexed: 10/25/2022]
Abstract
Perillyl alcohol (POH) is a dietary monoterpene with potential applications in chemoprevention and chemotherapy. Although clinical trials are under way, POH's physiological and pharmacological properties are still unclear. In the present study, the effect of POH on polycyclic aromatic hydrocarbon (PAH)-induced genotoxicity, and the related expression were examined in MCF-7 cells. Exposure to environmental toxicant increases the risk of cancer. Many of these compounds are pro-carcinogens and are biotransformed into their ultimate genotoxic structures by xenobiotic metabolizing enzymes. CYP1A1 and 1B1 are enzymes that catalyze the biotransformation of dimethylbenz[a]anthracene (DMBA). Our data revealed that 0.5 microM of POH was effective in blocking DMBA-DNA binding. Ethoxyresorufin-O-deethylase (EROD) assay indicated that the administration of POH inhibited the DMBA-induced enzyme activity in MCF-7 cells. Enzyme kinetic analysis revealed that POH inhibited CYP1B1 but not CYP1A1 activity. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay also demonstrated that the monoterpene reduced CYP1B1 mRNA abundance induced by DMBA. The present study illustrated that POH might inhibit and downregulate CYP1B1, which could protect against PAH-induced carcinogenesis.
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Affiliation(s)
- Nelson L S Chan
- Department of Biochemistry, The Chinese University of Hong Kong, Rm. 507C MMW Bldg., Shatin, N.T., Hong Kong
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81
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Coe KJ, Nelson SD, Ulrich RG, He Y, Dai X, Cheng O, Caguyong M, Roberts CJ, Slatter JG. Profiling the hepatic effects of flutamide in rats: a microarray comparison with classical aryl hydrocarbon receptor ligands and atypical CYP1A inducers. Drug Metab Dispos 2006; 34:1266-75. [PMID: 16611858 DOI: 10.1124/dmd.105.009159] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The antiandrogen flutamide (FLU) is used primarily for prostate cancer and is an idiosyncratic hepatotoxicant that sometimes causes severe liver problems. To investigate FLU's overt hepatic effects, especially on inducible drug clearance-related gene networks, FLU's hepatic gene expression profile was examined in female Sprague-Dawley rats using approximately 22,500 oligonucleotide microarrays. Rats were dosed daily for 3 days with FLU at 500, 250, 62.5, 31.3, and 15.6 mg/kg/day, and hepatic RNA was isolated. FLU resulted in the dose-dependent regulation of approximately 350 genes. Employing a gene-response compendium, FLU was compared with three classical aryl hydrocarbon receptor (AhR) ligands, 3-methylcholanthrene, benzo[a]pyrene, and beta-naphthoflavone, and four atypical CYP1A inducers, indole-3-carbinol (I3C), omeprazole (OME), chlorpromazine (CPZ), and clotrimazole (CLO). The FLU gene response was comparable with classical AhR ligands across a signature AhR ligand gene set that included CYP1A1 and other members of the AhR gene battery. Dose-related responses of CYP1 genes established a maximum response ceiling and discerned potency differences in atypical inducers. FLU had a sharp down-regulation of c-fos that was comparable with all the compounds except CPZ and CLO. FLU absorption, distribution, metabolism, and excretion (ADME) gene expression analysis revealed that FLU, as well as I3C and OME, induced CYP2B and CYP3A, distinguishing them from the classical AhR ligands. By using a compendium of gene expression profiles, FLU was shown to signal in rats similar to an AhR activator with additional CYP2B and CYP3A effects that most resembled the ADME gene expression pattern of the atypical CYP1A inducers I3C and OME.
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Affiliation(s)
- Kevin J Coe
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
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82
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Becker A, Albrecht C, Knaapen AM, Schins RPF, Höhr D, Ledermann K, Borm PJA. Induction of CYP1A1 in rat lung cells following in vivo and in vitro exposure to quartz. Arch Toxicol 2006; 80:258-68. [PMID: 16547697 DOI: 10.1007/s00204-006-0084-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Accepted: 02/13/2006] [Indexed: 10/24/2022]
Abstract
Respirable quartz has been classified as a human lung carcinogen, but the mechanism by which quartz exposure leads to lung cancer has not been clarified. Consistently higher risks of lung cancer are reported in smokers with quartz exposure and we therefore hypothesised that quartz exposure may alter the expression of enzyme systems involved in activation/detoxification of pre-carcinogens in cigarette smoke. More specifically we studied cytochrome P4501A1 (CYP1A1) expression using reverse transcriptase polymerase chain reaction and immunohistochemistry (IHC) upon in vitro and in vivo quartz exposure. In vitro incubation of rat lung epithelial cells with DQ12 quartz for 24 h showed a dose-dependent induction of CYP1A1-mRNA. On the other hand, CYP1A1 message was not increased in lung epithelial cells isolated from rats at 3, 28 or 90 days after intratracheal instillation of 2 mg DQ12. Following IHC for CYP1A1 protein in rat lung sections from later time-points (180 and 360 days), we observed an increase in the number of CYP1A1 positive cells. After in vivo quartz exposure, protein expression of the Aryl hydrocarbon receptor (AhR) was increased and nuclear translocation of AhR was observed at the same time-points. In conclusion, our findings demonstrate an effect of quartz exposure on chronic CYP1A1 expression in vivo, whereas the in vitro models show an immediate upregulation. We suggest that this upregulation of CYP1A1 may act as a co-carcinogenic pathway in quartz exposed workers by activation of pre-carcinogens such as those present in cigarette smoke.
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Affiliation(s)
- Andrea Becker
- Particle Research, Institut für Umweltmedizinische Forschung gGmbH an der Heinrich-Heine Universität, Dusseldorf, Germany
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83
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Yoon CY, Park M, Kim BH, Park JY, Park MS, Jeong YK, Kwon H, Jung HK, Kang H, Lee YS, Lee BJ. Gene Expression profile by 2,3,7,8-Tetrachlorodibenzo-p-Dioxin in the Liver of Wild-Type (AhR+/+) and Aryl Hydrocarbon Receptor-Deficient (AhR-/-) Mice. J Vet Med Sci 2006; 68:663-8. [PMID: 16891777 DOI: 10.1292/jvms.68.663] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is one of the most toxic environmental pollutants that cause various biological effects on mammals. The purpose of our study was to identify the genes involved in hepatotoxicity and hepatocarcinogenesis caused by TCDD. C57BL/6 (AhR+/+, wild type) and B6.129-AhR<tm1Bra>/J (AhR-/-, knock out) mice were injected i.p. with a single treatment of TCDD at the dose of 100 microg/kg body weight. Relative liver weight was significantly increased at 72 hr after TCDD treatment without an apparent histopathological change in AhR+/+ mice (p<0.05). TCDD treatment also significantly increased activity of serum alanine aminotransferase in AhR-/- mice (p<0.05). The liver was analyzed for gene expression profiles 72 hr later. As compared with AhR-/- mice, the expression of 51 genes (>3-fold) was changed in AhR+/+ mice; 28 genes were induced, while 23 genes were repressed. Most of the genes were associated with chemotaxis, inflammation, carcinogenesis, acute-phase response, immune responses, cell metabolism, cell proliferation, signal transduction, and tumor suppression. This study suggests that the microarray analysis of genes in the liver of AhR+/+ and AhR-/- mice may help to clarify the mechanism of AhR-mediated hepatotoxicity and hepatocarcinogenesis by TCDD.
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Affiliation(s)
- Chang Yong Yoon
- Department of Toxicology, National Institute of Toxicological Research, Seoul, Korea
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84
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Brevini TAL, Cillo F, Antonini S, Gandolfi F. Effects of endocrine disrupters on the oocytes and embryos of farm animals. Reprod Domest Anim 2005; 40:291-9. [PMID: 16008759 DOI: 10.1111/j.1439-0531.2005.00592.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Currently, approximately 60 chemicals have been identified as endocrine disruptors (EDs): exogenous agents that interfere with the synthesis, secretion, transport, metabolism, binding, action, or elimination of natural blood-borne hormones. Farm animals ingest these substances with food and drinking water. Their stability and lipid solubility has led to increased concern that these substances may compromise the reproductive health of both humans and animals. Oocytes are a permanent cell population established before birth which is exposed to environmental stimuli for a period that, in farm animals, can be as long as several years. Oocyte competence is acquired within the ovary during the developmental stages that precede ovulation and its role is critical during the interval between fertilization and the so-called maternal to embryonic transition, when the transcriptional activity of the embryonic genome becomes fully functional. Any perturbation of these delicate process is likely to reduce oocyte developmental competence and, therefore, to cause an arrest of embryonic development at any given stage. A critical analysis of the doses and time of exposure is presented together with a description of the effects of different EDs on farm animal oocytes and early embryonic development. Finally some of the mechanisms mediating EDs effects on the oocytes will be described. In particular the role of arylhydrocarbon receptor, maternal mRNA stability and cytoplasmic remodelling during oocyte maturation will be discussed in some details.
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Affiliation(s)
- T A L Brevini
- Department of Anatomy of Domestic Animals, University of Milan, Milan, Italy
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85
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Aluru N, Vuori K, Vijayan MM. Modulation of Ah receptor and CYP1A1 expression by alpha-naphthoflavone in rainbow trout hepatocytes. Comp Biochem Physiol C Toxicol Pharmacol 2005; 141:40-9. [PMID: 15949971 DOI: 10.1016/j.cca.2005.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Revised: 05/02/2005] [Accepted: 05/03/2005] [Indexed: 11/18/2022]
Abstract
The objective of this study was to evaluate whether alpha-naphthoflavone (ANF) modulates aryl hydrocarbon receptor (AhR) signaling in rainbow trout (Oncorhynchus mykiss). AhR and cytochrome P450 1A1 (CYP1A1) protein and mRNA content were used as indictors of AhR signaling. Primary culture of rainbow trout hepatocytes were exposed to different concentrations of ANF (10(-9)-10(-5) M), while beta-naphthoflavone (BNF 10(-10)-10(-6) M) and a combination of ANF and BNF were used to elucidate the impact of ANF on AhR signaling. ANF increased AhR and CYP1A1 protein expression in a concentration-related manner; the maximal induction was about 50% that of BNF. Despite the differences in protein content between ANF and BNF stimulation, the maximal AhR and CYP1A1 mRNA abundance seen with the high concentrations of ANF and BNF were similar. ANF significantly decreased ( approximately 50%) BNF-induced AhR protein expression (only at 10(-9) M), but not CYP1A1 protein and gene expression. In addition, ANF at a sub-maximal concentration (10(-7) M) did not affect BNF-induced AhR protein content, but increased the sensitivity of hepatocytes to BNF-mediated CYP1A1 protein expression. Taken together, the mode of action of ANF appears similar to BNF, including modulation of AhR expression and activation of AhR-mediated signaling in rainbow trout hepatocytes. Overall, ANF is not only a partial AhR agonist, but may also modify BNF-mediated AhR signaling in trout hepatocytes.
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Affiliation(s)
- Neelakanteswar Aluru
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1 Canada
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86
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Ferraris M, Flora A, Chiesara E, Fornasari D, Lucchetti H, Marabini L, Frigerio S, Radice S. Molecular mechanism of the aryl hydrocarbon receptor activation by the fungicide iprodione in rainbow trout (Oncorhynchus mykiss) hepatocytes. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2005; 72:209-220. [PMID: 15820101 DOI: 10.1016/j.aquatox.2004.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Revised: 12/10/2004] [Accepted: 12/19/2004] [Indexed: 05/24/2023]
Abstract
The dicarboximide fungicide iprodione (Ip) causes oxidative damage as a result of the production of free oxygen radicals, and induces cytochrome P4501A3 (CYP1A3) in cultured rainbow trout hepatocytes. The aim of this study was to characterise some of the molecular mechanisms by means of which Ip activates the aryl hydrocarbon receptor (AhR) and subsequently induces the CYP1A3 gene in rainbow trout (Oncorhynchus mykiss). The study was performed using primary hepatocytes and transfected HepG2 cells with a reporter construct, in which luciferase gene expression is under the transcriptional control of a multimerised xenobiotic response elements (4XREs), or a 2.3 Kb DNA fragment (corresponding to the trout CYP1A3 gene promoter). Ip exposure increased rainbow trout hepatocyte CYP1A3 mRNA over time and increased the expression of reporter gene in HepG2, thus suggesting that Ip induces the CYP1A3 gene by activating the AhR. Genistein, a tyrosine kinase inhibitor, efficiently inhibited the Ip-mediated induction of the CYP1A3 gene as demonstrated by mRNA level decrease and the impaired activation of the luciferase reporter gene constructs. Staurosporine, an inhibitor of protein kinase C, also suppressed the induction by Ip. When the AhR antagonist alpha-naphthoflavone was added to the cultures, Ip-mediated CYP1A3 induction was suppressed. These findings are consistent with a mechanism of Ip-mediated CYP1A3 gene induction that involves the activation of the AhR complex via phosphorylation-dephosphorylation reactions.
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Affiliation(s)
- Michela Ferraris
- Department of Pharmacology, Chemotherapy and Medical Toxicology E. Trabucchi, University of Milan, Via Vanvitelli 32, 20129 Milan, Italy.
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87
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Ramesh A, Walker SA, Hood DB, Guillén MD, Schneider K, Weyand EH. Bioavailability and risk assessment of orally ingested polycyclic aromatic hydrocarbons. Int J Toxicol 2005; 23:301-33. [PMID: 15513831 DOI: 10.1080/10915810490517063] [Citation(s) in RCA: 335] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are a family of toxicants that are ubiquitous in the environment. These contaminants generate considerable interest, because some of them are highly carcinogenic in laboratory animals and have been implicated in breast, lung, and colon cancers in humans. These chemicals commonly enter the human body through inhalation of cigarette smoke or consumption of contaminated food. Of these two pathways, dietary intake of PAHs constitutes a major source of exposure in humans. Although many reviews and books on PAHs have been published, factors affecting the accumulation of PAHs in the diet, their absorption following ingestion, and strategies to assess risk from exposure to these hydrocarbons following ingestion have received much less attention. This review, therefore, focuses on concentrations of PAHs in widely consumed dietary ingredients along with gastrointestinal absorption rates in humans. Metabolism and bioavailability of PAHs in animal models and the processes, which influence the disposition of these chemicals, are discussed. The utilitarian value of structure and metabolism in predicting PAH toxicity and carcinogenesis is also emphasized. Finally, based on intake, disposition, and tumorigenesis data, the exposure risk to PAHs from diet, and contaminated soil is presented. This information is expected to provide a framework for refinements in risk assessment of PAHs from a multimedia exposure perspective.
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Affiliation(s)
- Aramandla Ramesh
- Department of Pharmacology, Meharry Medical College, Nashville, Tennessee 37208, USA.
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88
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Sidorova YA, Grishanova AY, Lyakhovich VV. Rat hepatic CYP1A1 and CYP1A2 induction by menadione. Toxicol Lett 2005; 155:253-8. [PMID: 15603920 DOI: 10.1016/j.toxlet.2004.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2004] [Revised: 08/03/2004] [Accepted: 10/05/2004] [Indexed: 11/23/2022]
Abstract
The effects of menadione on activities and expression of cytochrome P450 (CYP) 1A subfamily (CYP1A) isozymes in rat hepatic tissue were examined. When rats were treated orally with 15 mg/kg menadione for 4 days, the elevation of hepatic CYP1A1/1A2 specific activities in microsomal preparations was detected with approximately 5.4- and 2.5-fold increase over control values for ethoxyresorufin-O-deethylase (EROD, CYP1A1) and methoxyresorufin-O-demethylase (MROD, CYP1A2) activities, respectively. CYP1A1 and CYP1A2 mRNA levels in the liver of menadione-treated rats were approximately 11.8- and 1.8-fold higher than in controls, respectively, whereas the expression of the CYP1A regulatory proteins aryl hydrocarbon-receptor (AhR) and AhR nuclear translocator (Arnt) was not changed at the mRNA level. The result of this study demonstrates that menadione induces CYP1A1/1A2 expression in vivo through either transcriptional activation and/or mRNA stabilization.
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Affiliation(s)
- Y A Sidorova
- Institute of Molecular Biology and Biophysics, Siberian Division of Russian Academy of Medical Sciences, Timakova str. 2, Novosibirsk 630090, Russia.
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89
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Campbell SJ, Henderson CJ, Anthony DC, Davidson D, Clark AJ, Wolf CR. The murine Cyp1a1 gene is expressed in a restricted spatial and temporal pattern during embryonic development. J Biol Chem 2004; 280:5828-35. [PMID: 15572371 DOI: 10.1074/jbc.m412899200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In adult mice the cytochrome P450 Cyp1a1 gene is not constitutively expressed but is highly inducible by foreign compounds acting through the aryl hydrocarbon (Ah) receptor. However, the expression profile of the Cyp1a1 gene in the developing embryo is not well under-stood. Using established transgenic mouse lines where 8.5 kb of the rat CYP1A1 promoter is cloned upstream of the lacZ reporter gene (1), we describe the expression of the CYP1A1-driven reporter gene in all tissues through-out stages E7-E14 of embryonic development. In contrast to the absence of constitutive Cyp1a1 and lacZ transgene expression in tissues of the adult mouse, a constitutive cell-specific and time-dependent pattern of CYP1A1 promoter activity was observed in the embryo. This expression pattern was confirmed as reflecting the endogenous gene by measuring Cyp1a1 mRNA levels and protein expression by immunohistochemistry. The number of cells displaying endogenous CYP1A1 activity could be increased in the embryo upon xenobiotic challenge, but only within areas where the CYP1A1 promotor was already active. When reporter mice were bred onto a genetic background expressing a lower affinity form of the Ah receptor (DBA allele), transgene and murine Cyp1a1 protein expression were both attenuated in the adult mouse liver upon xenobiotic challenge. By comparison, constitutive CYP1A1 promoter activity in the embryo was identical in the presence of either the high or low affinity Ah receptor. These novel data suggest that the Cyp1a1 protein may play a role in murine development and that regulation of the Cyp1a1 gene during this period is either through the action of a high affinity Ah receptor ligand or by an alternative regulatory pathway.
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Affiliation(s)
- Sandra J Campbell
- Cancer Research UK Molecular Pharmacology Unit, Biomedical Research Centre, University of Dundee, Level 5, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
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90
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Czekaj P, Wiaderkiewicz A, Florek E, Wiaderkiewicz R. Tobacco smoke-dependent changes in cytochrome P450 1A1, 1A2, and 2E1 protein expressions in fetuses, newborns, pregnant rats, and human placenta. Arch Toxicol 2004; 79:13-24. [PMID: 15448981 DOI: 10.1007/s00204-004-0607-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Accepted: 08/10/2004] [Indexed: 10/26/2022]
Abstract
Tobacco smoke (TS) was described as a mixture of numerous cytochrome P450 (P450) substrates, inducers, and inhibitors. These inducers and inhibitors may modify drug clearance and xenobiotic or endogenous metabolism affecting P450s expression. In the present study, the effect of gestation and TS on: (1) cytochrome P450 CYP1A1, CYP1A2, and CYP2E1 protein expressions, and (2) cytochrome P450-linked microsomal enzyme activities, were studied in fetal rat liver, rat, and human placenta and in newborn and adult rat hepatic and extrahepatic tissues. Non-pregnant and pregnant 4-month-old female Wistar rats were exposed to TS (500, 1,000, or 1,500 mg carbon monoxide per m(3) air) in a toxicological chamber for 3 weeks (6 h daily, 5 days weekly). Human placentas were sampled from non-smoking, passive smoking, or active smoking primiparas. The efficacy of exposure was assessed by measuring urine cotinine levels. The TS-dependent inductory effect on the expression of CYP1A1 and 1A2 and related monooxygenase activities, and the inhibitory/inductory effect on CYP2E1 expression in rat tissues were observed. Pregnancy was associated with decreased levels of constitutive CYP1A1 and 2E1 in hepatic and extrahepatic tissues, TS-inducible CYP1A2 expression in the liver, and CYP1A1 expression in lungs and heart, but had no inhibitory effect on TS-inducible CYP1A1 and 2E1 expression, EROD, and P450-cooperated enzyme activities in the liver, kidney, and, in the latter case, in the heart. The presence of TS-induced CYP1A1 protein was confirmed in rat and human placenta and showed in newborn liver and lungs. CYP1A2 and 2E1 proteins were detectable in fetal rat liver. It was concluded that the expression of CYP1A1, 1A2, and 2E1, which metabolize some drugs and activate carcinogens, is controlled by age-, pregnancy-, and tissue-specific regulatory mechanisms in rats. Gestational differences in the regulation of expression of CYP1A subfamily members are not excluded. CYP1A1 and 2E1, but not CYP1A2 inductory mechanisms seem to be functional in fetal liver at day 21 of pregnancy but they appeared to be uninducible under a TS exposure. In TS-exposed pregnant females and fetuses the effects of metabolic activation of CYP1A1 and 1A2 substrates might be reduced because of lower CYP expressions or poor induction, respectively.
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Affiliation(s)
- Piotr Czekaj
- II Department of Histology & Embryology, Medical University of Silesia, Medyków 18, 40-752, Katowice, Poland.
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91
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Fallone F, Villard PH, Sérée E, Rimet O, Nguyen QB, Bourgarel-Rey V, Fouchier F, Barra Y, Durand A, Lacarelle B. Retinoids repress Ah receptor CYP1A1 induction pathway through the SMRT corepressor. Biochem Biophys Res Commun 2004; 322:551-6. [PMID: 15325265 DOI: 10.1016/j.bbrc.2004.07.153] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Indexed: 10/26/2022]
Abstract
CYP1A1 isoform is mainly regulated by the transcription factor AhR and to a lesser extent by the nuclear receptor RAR. The effect of a coexposure with 3MC, a AhR ligand, and RA, a RAR ligand, which are, respectively, strong and weak CYP1A1 inducers, is poorly known. We showed in Caco-2 cells that addition of RA significantly decreased 3MC-induced CYP1A1 expression by -55% for mRNA level and -30% for promoter and enzymatic activities. We further showed that RA decreased AhR protein level. Moreover, a physical interaction between AhR and the RAR-corepressor SMRT has been described in vitro. Using the corepressor inhibitor TSA, transfected-cells with SMRT cDNA, and coimmunoprecipitation experiments, we demonstrated that RA addition repressed AhR function through a marked AhR/SMRT physical interaction. This interaction explains the decrease of 3MC-induced CYP1A1 expression. This new mechanism involving the repression of AhR-induced CYP1A1 expression by retinoids allows better knowledge of the CYP1A1 regulation.
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Affiliation(s)
- Frédérique Fallone
- FRE CNRS 2737, Faculté de Pharmacie, Université de la Méditerranée, 27 Bd Jean Moulin, 13385 Marseille Cedex 05, France
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92
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Tan Z, Huang M, Puga A, Xia Y. A critical role for MAP kinases in the control of Ah receptor complex activity. Toxicol Sci 2004; 82:80-7. [PMID: 15272135 DOI: 10.1093/toxsci/kfh228] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The heterodimeric complex of aromatic hydrocarbon receptor (AHR) and Ah receptor nuclear translocator (ARNT) plays a pivotal role in controlling the expression of drug metabolism genes, such as the cytochromes p450 (Cyp) 1a1 and 1b1, believed to be responsible for most toxic effects of the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In this study, we show that activation of Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) modulates ARNT transcription activity and potentiates the transcriptional activity of AHR/ARNT complexes. Inhibition of ERK by chemical compounds and ablation of JNK caused significant decreases in CYP1A1 induction by TCDD. Compared to wild type, JNK2 ablation significantly reduced TCDD-stimulated CYP1A1 expression in mouse thymus and testis, but not in liver. In contrast, CYP1B1 expression was unaffected in all three tissues of the knockout mice. These data suggest that JNK and ERK modulate ARNT activity and AHR/ARNT-dependent gene expression, contributing to the gene-specific and tissue-specific toxicity of environmental contaminants.
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Affiliation(s)
- Zongqing Tan
- Center for Environmental Genetics and Department of Environmental Health, University of Cincinnati Medical Center, 123 E. Shields Street, Cincinnati, OH 45267-0056, USA
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93
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Vrzal R, Ulrichová J, Dvořák Z. AROMATIC HYDROCARBON RECEPTOR STATUS IN THE METABOLISM OF XENOBIOTICS UNDER NORMAL AND PATHOPHYSIOLOGICAL CONDITIONS. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2004. [DOI: 10.5507/bp.2004.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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94
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Murphy KA, Villano CM, Dorn R, White LA. Interaction between the Aryl Hydrocarbon Receptor and Retinoic Acid Pathways Increases Matrix Metalloproteinase-1 Expression in Keratinocytes. J Biol Chem 2004; 279:25284-93. [PMID: 15075337 DOI: 10.1074/jbc.m402168200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Exposure to the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) results in a variety of pathological lesions in humans via activation of the aryl hydrocarbon receptor (AhR) pathway. It has become apparent that this pathway interacts with a variety of signaling pathways that are believed to be involved in mediating TCDD/AhR biological effects. Our hypothesis is that TCDD mediates these pathological lesions by directly altering the expression of genes involved in matrix deposition and remodeling and that the retinoic acid signaling pathway is involved in modulating TCDD-induced effects. Therefore, we examined the effect of TCDD and all-trans retinoic acid (atRA) on the expression of matrix metalloproteinase-1 (MMP-1, interstitial collagenase), one of the proteolytic enzymes that degrade type I collagen, in normal human keratinocytes. The data show that TCDD exposure results in increased MMP-1 expression in keratinocytes that is further enhanced by co-treatment with all-trans retinoic acid. TCDD-induced expression of MMP-1 appears to be mediated through two AP-1 elements in the proximal promoter of the MMP-1 gene. However, retinoic acid-mediated induction of keratinocyte MMP-1 is a result of both promoter activation and increased mRNA stability. These findings are the first to demonstrate TCDD-induced expression of MMP-1 and to demonstrate interactions between the TCDD/AhR and retinoic acid pathways on MMP-1 expression.
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Affiliation(s)
- Kyle A Murphy
- Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA
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95
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Uno S, Dalton TP, Derkenne S, Curran CP, Miller ML, Shertzer HG, Nebert DW. Oral Exposure to Benzo[a]pyrene in the Mouse: Detoxication by Inducible Cytochrome P450 Is More Important Than Metabolic Activation. Mol Pharmacol 2004; 65:1225-37. [PMID: 15102951 DOI: 10.1124/mol.65.5.1225] [Citation(s) in RCA: 236] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The cytochrome P450 (CYP1A1) enzyme metabolically activates many polycyclic aromatic hydrocarbons, including benzo[a]pyrene (BaP), to DNA- and protein-binding intermediates that are associated with toxicity, mutagenesis, and carcinogenesis. As a result, it is widely accepted that CYP1A1 potentiates the toxicity of this class of chemicals. In distinct contrast, we show here that CYP1A1 inducibility is essential in the detoxication of oral BaP. We compared Cyp1a1(-/-) knockout mice, having the genetic absence of the CYP1A1 enzyme, with Cyp1a1(+/+) wild-type mice. At an oral BaP dose of 125 mg/kg/day, Cyp1a1(-/-) mice died within 30 days whereas Cyp1a1(+/+) mice displayed no outward signs of toxicity. The rate of BaP clearance was 4-fold slower in Cyp1a1(-/-) than Cyp1a1(+/+) mice. The cause of death in Cyp1a1(-/-) mice receiving oral BaP seemed to be immunotoxicity, including toxic chemical depression of the bone marrow; some toxic effects in Cyp1a1(-/-) mice were noted at a BaP dose as low as 1.25 mg/kg/day. DNA post-labeling studies demonstrated dramatically higher BaP-DNA adduct levels in all Cyp1a1(-/-) tissues assayed, with the exception of the small intestine, which is probably a major site of BaP metabolism in Cyp1a1(+/+) mice. Different BaP-DNA adduct patterns were also observed between the two genotypes receiving oral BaP. Despite previous studies in vitro and in cell culture that have shown a participatory role for CYP1A1 in BaP toxicity, the present data indicate that, in the intact animal, inducible CYP1A1 is extremely important in detoxication and protection against oral BaP toxicity.
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Affiliation(s)
- Shigeyuki Uno
- Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati Medical Center, OH 45267-0056, USA
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96
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Albrecht EA, Chinnaiyan AM, Varambally S, Kumar-Sinha C, Barrette TR, Sarma JV, Ward PA. C5a-induced gene expression in human umbilical vein endothelial cells. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:849-59. [PMID: 14982839 PMCID: PMC1613300 DOI: 10.1016/s0002-9440(10)63173-2] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The endothelium plays a critical role in the inflammatory process. The complement activation product, C5a, is known to have proinflammatory effects on the endothelium, but the molecular mechanisms remain unclear. We have used cDNA microarray analysis to assess gene expression in human umbilical vein endothelial cells (HUVECs) that were stimulated with human C5a in vitro. Chip analyses were confirmed by reverse transcriptase-polymerase chain reaction and by Western blot analysis. Gene activation responses were remarkably similar to gene expression patterns of HUVECs stimulated with human tumor necrosis factor-alpha or bacterial lipopolysaccharide. HUVECs stimulated with C5a showed progressive increases in gene expression for cell adhesion molecules (eg, E-selectin, ICAM-1, VCAM-1), cytokines/chemokines, and related receptors (eg, VEGFC, IL-6, IL-18R). Surprisingly, HUVECs showed little evidence for up-regulation of complement-related genes. There were transient increases in gene expression associated with broad functional activities. The three agonists used also caused down-regulation of genes that regulate angiogenesis and drug metabolism. With a single exception, C5a caused little evidence of activation of complement-related genes. These studies indicate that endothelial cells respond robustly to C5a by activation of genes related to progressive expression of cell adherence molecules, and cytokines and chemokines in a manner similar to responses induced by tumor necrosis factor-alpha and lipopolysaccharide.
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Affiliation(s)
- Eric A Albrecht
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0602, USA
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97
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Naruse M, Otsuka E, Naruse M, Ishihara Y, Miyagawa-Tomita S, Hagiwara H. Inhibition of osteoclast formation by 3-methylcholanthrene, a ligand for arylhydrocarbon receptor: suppression of osteoclast differentiation factor in osteogenic cells. Biochem Pharmacol 2004; 67:119-27. [PMID: 14667934 DOI: 10.1016/j.bcp.2003.08.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the effects of 3-methylcholanthrene (3MC), a ligand for arylhydrocarbon receptor (AhR), on osteoclastogenesis. Osteoclast-like cells, in cocultures with mouse spleen cells and clonal osteogenic stromal ST2 cells, are formed from spleen cells by a combination of the receptor activator of nuclear factor-kappaB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) produced by ST2 cells in response to 1alpha,25(OH)(2) Vitamin D(3). 3MC dose-dependently inhibited the formation of mono- and multinuclear osteoclast-like cells. However, 3MC did not inhibit the formation of osteoclast-like cells from mouse spleen cells which was supported by the exogenous soluble RANKL and M-CSF. 3MC did not affect the formation of an actin ring and pits on slices of dentine by osteoclast-like cells, both of which are typical indices of osteoclast activity. These results suggest that 3MC affects osteoclast-supporting cells such as ST2 cells but not osteoclast precursor cells and mature osteoclastic cells. When we measured the expression levels of RANKL mRNA in ST2 cells, 3MC dose-dependently decreased the level of this mRNA. However, 3MC did not affect levels of mRNAs for osteoprotegerin (OPG), M-CSF, and the receptor of 1alpha,25(OH)(2) Vitamin D(3) in ST2 cells. Furthermore, soluble RANKL was able to counteract the inhibitory effect of 3MC on the formation of osteoclast-like cells. Our findings indicate that 3MC inhibits osteoclastogenesis via the inhibition of RANKL expression in osteoblastic cells.
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Affiliation(s)
- M Naruse
- Department of Biological Sciences, Tokyo Institute of Technology, 226-8501, Yokohama, Japan
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98
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Nakatsuru Y, Wakabayashi K, Fujii-Kuriyama Y, Ishikawa T, Kusama K, Ide F. Dibenzo[A,L]pyrene-induced genotoxic and carcinogenic responses are dramatically suppressed in aryl hydrocarbon receptor-deficient mice. Int J Cancer 2004; 112:179-83. [PMID: 15352028 DOI: 10.1002/ijc.20365] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Dibenzo[a,l]pyrene (DB[a,l]P), a notorious air pollutant, is the most powerful carcinogenic polycyclic aromatic hydrocarbon (PAH) ever tested. Although the carcinogenicity of PAH may be primarily mediated by the aryl hydrocarbon receptor (AhR), the in vivo role of AhR in skin carcinogenesis remains to be defined. In this context, we investigated the genotoxic and carcinogenic responses of the AhR-deficient mouse skin to DB[a,l]P. A single painting resulted in a striking epidermal hyperplasia in AhR+/+ mice but not in AhR-/- mice. Bromodeoxyuridine-labeling index and accumulation of p53 protein in epidermal cells of AhR+/+ mice were 8- and 33-fold higher than those of AhR-/- mice, respectively. 32P-Postlabeling assay for DB[a,l]P-DNA adducts displayed a 2-fold increase in the AhR+/+ mouse skin. After DB[a,l]P exposure, AhR-/- mice arranged a nearly 60% reduction in the induction of epidermal cytochrome P450 (CYP)1A1, but CYP1B1 was constitutively expressed in both genotypes of mice, irrespective of DB[a,l]P treatment. As compared with AhR+/+ mice, AhR-/- mice had both significantly lower incidence (100% vs. 33%) and multiplicity (2.7 vs. 0.46) of skin tumors by the complete carcinogenesis study. These observations indicate that a reduced tumor yield in AhR-/- mice may be secondary to reduction of inducible CYP1A1 activation and subsequent DNA adduction. It is evident from our continuous work that although AhR is likely to play a central role in epidermal proliferation and possibly neoplastic transformation, the relative importance of AhR for carcinogenesis may be different among PAH examined.
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Affiliation(s)
- Yoko Nakatsuru
- Department of Pathology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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Huc L, Sparfel L, Rissel M, Dimanche-Boitrel MT, Guillouzo A, Fardel O, Lagadic-Gossmann D. Identification of Na+/H+exchange as a new target for toxic polycyclic aromatic hydrocarbons in liver cells. FASEB J 2003; 18:344-6. [PMID: 14656999 DOI: 10.1096/fj.03-0316fje] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ubiquitous environmental pollutants polycyclic aromatic hydrocarbons are responsible for important carcinogenic and apoptotic effects, whose mechanisms are still poorly understood, owing to the multiplicity of possible cellular targets. Among these mechanisms, alterations of ionic homeostasis have been suggested. In this work, the effects of benzo(a)pyrene [B(a)P] on pHi were tested in the rat liver F258 epithelial cell line, using the fluoroprobe carboxy-SNARF-1. After a 48-h treatment, B(a)P (50 nM) induced an alkalinization, followed by an acidification after 72 h and the development of apoptosis. Determinations of pH(i) recovery following an acid load showed an increased acid efflux at 48 h. Cariporide inhibited both the early alkalinization and the increased acid efflux, thus suggesting the involvement of Na+/H+ exchanger 1 (NHE1). Besides, alpha-naphtoflavone (alpha-NF), an inhibitor of CYP1A1-mediated B(a)P metabolism, prevented all pH(i) changes, and NHE1 activation was blocked by the antioxidant thiourea, which inhibited CYP1A1 metabolism-dependent H2O2 production. Regarding B(a)P-induced apoptosis, this was prevented by alpha-NF and bongkrekic acid, an inhibitor of mitochondria-dependent apoptosis. Interestingly, apoptosis was significantly reduced by cariporide. Taken together, our results indicate that B(a)P, via H2O2 produced by CYP1A1-dependent metabolism, induces an early activation of NHE1, resulting in alkalinization; this appears to play a significant role in mitochondria-dependent B(a)P-induced apoptosis.
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Affiliation(s)
- Laurence Huc
- INSERM U456, Détoxication et Réparation Tissulaire, Faculté de Pharmacie, Université Rennes 1, 35043 Rennes Cedex, France
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100
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Montero R, Serrano L, Dávila VM, Ito A, Plancarte A. Infection of rats with Taenia taeniformis metacestodes increases hepatic CYP450, induces the activity of CYP1A1, CYP2B1 and COH isoforms and increases the genotoxicity of the procarcinogens benzo[a]pyrene, cyclophosphamide and aflatoxin B(1). Mutagenesis 2003; 18:211-6. [PMID: 12621079 DOI: 10.1093/mutage/18.2.211] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Infection of rat liver by Taenia taeniformis metacestodes produced an increase in total CYP450 content and induced activity of the CYP1A1, CYP2B1 and COH isoforms. Variations in activity and p450 total content were found with increasing time of infection. During increased activity of p450 isoforms, rats were challenged with carcinogens metabolized by the mentioned isozymes and an increased amount of genotoxic damage was found when benzo[a] pyrene, cyclophosphamide and aflatoxin B(1) were used. No change was seen in CYP2E1 activity. These results support previous findings regarding an increased susceptibility to genotoxic damage of infected organisms.
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Affiliation(s)
- Regina Montero
- Instituto de Investigaciones Biomédicas and Facultad de Medicina, UNAM, Apdo Postal 70228, CP 04510, México DF, Mexico.
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