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HADDAD S. CYP1A1* 2 A gene polymorphism frequency in Syrian breast cancer patients. Meta Gene 2021. [DOI: 10.1016/j.mgene.2021.100861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Sridhar J, Goyal N, Liu J, Foroozesh M. Review of Ligand Specificity Factors for CYP1A Subfamily Enzymes from Molecular Modeling Studies Reported to-Date. Molecules 2017; 22:molecules22071143. [PMID: 28698457 PMCID: PMC6152251 DOI: 10.3390/molecules22071143] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/01/2017] [Accepted: 07/03/2017] [Indexed: 02/03/2023] Open
Abstract
The cytochrome P450 (CYP) family 1A enzymes, CYP1A1 and CYP1A2, are two of the most important enzymes implicated in the metabolism of endogenous and exogenous compounds through oxidation. These enzymes are also known to metabolize environmental procarcinogens into carcinogenic species, leading to the advent of several types of cancer. The development of selective inhibitors for these P450 enzymes, mitigating procarcinogenic oxidative effects, has been the focus of many studies in recent years. CYP1A1 is mainly found in extrahepatic tissues while CYP1A2 is the major CYP enzyme in human liver. Many molecules have been found to be metabolized by both of these enzymes, with varying rates and/or positions of oxidation. A complete understanding of the factors that govern the specificity and potency for the two CYP 1A enzymes is critical to the development of effective inhibitors. Computational molecular modeling tools have been used by several research groups to decipher the specificity and potency factors of the CYP1A1 and CYP1A2 substrates. In this review, we perform a thorough analysis of the computational studies that are ligand-based and protein-ligand complex-based to catalog the various factors that govern the specificity/potency toward these two enzymes.
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Affiliation(s)
- Jayalakshmi Sridhar
- Department of Chemistry, Xavier University of Louisiana, 1 Drexel Dr., New Orleans, LA 70125, USA.
| | - Navneet Goyal
- Department of Chemistry, Xavier University of Louisiana, 1 Drexel Dr., New Orleans, LA 70125, USA.
| | - Jiawang Liu
- Department of Chemistry, Xavier University of Louisiana, 1 Drexel Dr., New Orleans, LA 70125, USA.
| | - Maryam Foroozesh
- Department of Chemistry, Xavier University of Louisiana, 1 Drexel Dr., New Orleans, LA 70125, USA.
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Fernandes GMM, Russo A, Proença MA, Gazola NF, Rodrigues GH, Biselli-Chicote PM, Silva AE, Netinho JG, Pavarino &EC, Goloni-Bertollo EM. CYP1A1, CYP2E1 and EPHX1 polymorphisms in sporadic colorectal neoplasms. World J Gastroenterol 2016; 22:9974-9983. [PMID: 28018104 PMCID: PMC5143764 DOI: 10.3748/wjg.v22.i45.9974] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/08/2016] [Accepted: 11/16/2016] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the contribution of polymorphisms in the CYP1A1, CYP2E1 and EPHX1 genes on sporadic colorectal cancer (SCRC) risk.
METHODS Six hundred forty-one individuals (227 patients with SCRC and 400 controls) were enrolled in the study. The variables analyzed were age, gender, tobacco and alcohol consumption, and clinical and histopathological tumor parameters. The CYP1A1*2A, CYP1A1*2C CYP2E1*5B and CYP2E1*6 polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The EPHX1 Tyr113His, EPHX1 His139Arg and CYP1A1*2C polymorphisms were detected by real-time PCR. Chi-squared test and binary logistic regression were used in the statistical analysis. Haplotype analysis was conducted using the Haploview program, version 2.05.
RESULTS Age over 62 years was a risk factor for SCRC development (OR = 7.54, 95%CI: 4.94-11.50, P < 0.01). Male individuals were less susceptible to SCRC (OR = 0.55, 95%CI: 0.35-0.85, P < 0.01). The CYP2E1*5B polymorphism was associated with SCRC in the codominant (heterozygous genotype: OR = 2.66, 95%CI: 1.64-4.32, P < 0.01), dominant (OR = 2.82, 95%CI: 1.74-4.55, P < 0.01), overdominant (OR = 2.58, 95%CI: 1.59-4.19, P < 0.01), and log-additive models (OR = 2.84, 95%CI: 1.78-4.52, P < 0.01). The CYP2E1*6 polymorphism was associated with an increased SCRC risk in codominant (heterozygous genotype: OR = 2.81, 95%CI: 1.84-4.28, P < 0.01; homozygous polymorphic: OR = 7.32, 95%CI: 1.85-28.96, P < 0.01), dominant (OR = 2.97, 95%CI: 1.97-4.50, P < 0.01), recessive (OR = 5.26, 95%CI: 1.35-20.50, P = 0.016), overdominant (OR = 2.64, 95%CI: 1.74-4.01, P < 0.01), and log-additive models (OR = 2.78, 95%CI: 1.91-4.06, P < 0.01). The haplotype formed by the minor alleles of the CYP2E1*5B (C) and CYP2E1*6 (A) polymorphisms was associated with SCRC (P = 0.002). However, the CYP1A1*2A, CYP1A1*2C, EPHX1 Tyr113His and EPHX1 His139Arg polymorphisms were not associated with SCRC.
CONCLUSION In conclusion, the results demonstrated that CYP2E1*5B and CYP2E1*6 minor alleles play a role in the development of SCRC.
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Genome Editing of the CYP1A1 Locus in iPSCs as a Platform to Map AHR Expression throughout Human Development. Stem Cells Int 2016; 2016:2574152. [PMID: 27148368 PMCID: PMC4842384 DOI: 10.1155/2016/2574152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/17/2016] [Indexed: 12/12/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that increases the expression of detoxifying enzymes upon ligand stimulation. Recent studies now suggest that novel endogenous roles of the AHR exist throughout development. In an effort to create an optimized model system for the study of AHR signaling in several cellular lineages, we have employed a CRISPR/CAS9 genome editing strategy in induced pluripotent stem cells (iPSCs) to incorporate a reporter cassette at the transcription start site of one of its canonical targets, cytochrome P450 1A1 (CYP1A1). This cell line faithfully reports on CYP1A1 expression, with luciferase levels as its functional readout, when treated with an endogenous AHR ligand (FICZ) at escalating doses. iPSC-derived fibroblast-like cells respond to acute exposure to environmental and endogenous AHR ligands, and iPSC-derived hepatocytes increase CYP1A1 in a similar manner to primary hepatocytes. This cell line is an important innovation that can be used to map AHR activity in discrete cellular subsets throughout developmental ontogeny. As further endogenous ligands are proposed, this line can be used to screen for safety and efficacy and can report on the ability of small molecules to regulate critical cellular processes by modulating the activity of the AHR.
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Amrani I, Bulatova N, Awidi A, Yousef AM, Melhem JM, Al-Masri M, Tahoun LA. Lack of Association between CYP1A1 M2 and M4 Polymorphisms and Breast Carcinoma in Jordanian Women: a Case-Control Study. Asian Pac J Cancer Prev 2016; 17:387-93. [DOI: 10.7314/apjcp.2016.17.1.387] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Mutation and protein expression analysis of CYP1A1 gene-a study on female breast cancer cases from India. Tumour Biol 2013; 35:1965-71. [PMID: 24096584 DOI: 10.1007/s13277-013-1262-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 09/25/2013] [Indexed: 10/26/2022] Open
Abstract
Increased risk may be associated with exposure to genotoxic agents during breast development because the undifferentiated ductal elements of breast are more susceptible to the action of genotoxic early in life and thus an impairment in Cytochrome P 4501A1 (CYP1A1) may contribute to the development of breast cancer. Therefore, we carried out the population-based study in a total of 105 Indian female breast cancer cases with equal normal adjacent controls. A total of 20 samples (20/105, 19.04 %) showed final mutations in the exon 7 of the CYP1A1 gene where 5 cases harbored frame shift mutation (deletion of G nucleotide), and the remaining were missense mutation observed in 15 cases of breast cancer with significant association to histological grade (chi square -7.20, p = 0.02), tumor stage (chi square -6.36, p = 0.01), menopausal stage (chi square -9.76, p = 0.001), and ER status (chi square -4.22, p = 0.03). We further did protein expression analysis of CYP1A1 through immunohistochemistry where 66 cases showed down or no expression (+) (66/105, 62.85 %), 28 cases with moderate expression (++) (28/105, 26.66 %), and 11 cases with high expression (+++) (11/105, 10.47 %). Highly significant associations were observed between protein expression and clinico-pathological variables like Her 2 category (chi square = 31.73, p < 0.0001) and tumor stage (chi square = 10.27, p = 0.005). Importantly, mutation(s) of the type like deletion of A nucleotide and missense mutation (Gly > Val) exclusively showed low (+) or no expression for the CYP1A1 protein when studied in relation to each other. In summary, CYP1A1 may be associated with breast cancer and its down regulation may serve as an important tool in the field of biomarker study.
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Szabó K, Kemény L. Studying the genetic predisposing factors in the pathogenesis of acne vulgaris. Hum Immunol 2011; 72:766-73. [PMID: 21669244 DOI: 10.1016/j.humimm.2011.05.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 04/28/2011] [Accepted: 05/13/2011] [Indexed: 02/04/2023]
Abstract
Acne is one of the most common dermatologic diseases in the developed regions of the world, affecting a large percentage of the population. Despite the great improvement in the number and quality of studies of the molecular etiology of this disease in the past 3 decades, the detailed molecular pathogenesis and the cause of the large individual variations in severity of skin symptoms remain unknown. The roles of genetic inheritance and special genetic susceptibility and protective factors have been suggested for over 100 years, but their identification and determination started only in the 1990s. To date, only a small number of genetic polymorphisms affecting the expression and/or function of a handful of genes have been investigated. This review surveys the major findings of the classic and molecular genetic studies that have been conducted in this field, draws conclusions, and indicates how the available data help our current understanding of the pathogenesis of this common skin disease.
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Affiliation(s)
- Kornélia Szabó
- Dermatological Research Group of the Hungarian Academy of Sciences, Szeged, Hungary.
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CORDERO KARINA, ESPINOZA IRIS, CACERES DANTE, ROCO ANGELA, MIRANDA CARLA, SQUICCIARINI VALENTINA, SANTANDER PAULA, LEE KUEN, SAAVEDRA IVÁN, QUIÑONES LUIS. Oral cancer susceptibility associated with the CYP1A1 and GSTM1 genotypes in Chilean individuals. Oncol Lett 2010; 1:549-553. [PMID: 22966341 PMCID: PMC3436421 DOI: 10.3892/ol_00000097] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 03/03/2010] [Indexed: 11/06/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) contained in tobacco smoke acquire carcinogenicity following their activation by xenobiotic-metabolizing enzymes to highly reactive metabolites. The cytochrome P4501A1 (CYP1A1) enzyme is central to the metabolic activation of these PAHs, and GSTM1 is the main enzyme responsible for its detoxification. CYP1A1 and GSTM1 polymorphisms were evaluated in 124 Chilean healthy controls and 48 oral cancer patients through PCR-based restriction fragment length polymorphism. In the healthy controls, frequencies of the CYP1A1 variant alleles for m1 (CYP1A1(*)2A) and the GSTM1null genotype were found to be 0.25 and 0.19, respectively. In the oral cancer patients, these frequencies were 0.33 and 0.50, respectively. Thus, the GSTM1 and m1 rare alleles were significantly more frequent in the oral cancer patients compared to the controls. The estimated relative risk for oral cancer associated with the single genotype CYP1A1 or GSTM1 was 2.08 for wt/m1, 1.04 for m1/m1 and 4.16 for the GSTM1null genotype. For smokers, the estimated relative risk (adjusted by age and gender) was higher in the individuals carrying the m1 allele of CYP1A1 [wt/m1: odds ratio (OR)=5.68, P=0.0080; m1/m1: OR=7.77, P=0.0420] or GSTM1null genotype (OR=20.81, P<0.0001). Combined genotypes CYP1A1 and GSTM1 increased the risk significantly (wt/m1/GSTM1null: OR=19.14, P=0.0030; m1/m1/GSTM1null: OR=21.39, P=0.0130). Taken together, these findings suggest that Chilean individuals carrying single or combined GSTM1 and CYP1A1 polymorphisms may be more susceptible to oral cancer induced by environmental tobacco smoking.
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Affiliation(s)
- KARINA CORDERO
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
| | - IRIS ESPINOZA
- Department of Oral Pathology, Faculty of Odontology, University of Chile, Chile
| | - DANTE CACERES
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
- Epidemiology Division, School of Public Health, Faculty of Medicine, University of Chile, Chile
| | - ANGELA ROCO
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
- San Juan de Dios Hospital, Santiago, Chile
| | - CARLA MIRANDA
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
- San Juan de Dios Hospital, Santiago, Chile
| | - VALENTINA SQUICCIARINI
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
| | - PAULA SANTANDER
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
| | - KUEN LEE
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
| | - IVÁN SAAVEDRA
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
| | - LUIS QUIÑONES
- Center of Pharmacological and Toxicological Research (IFT), Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
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Li R, Shugart YY, Zhou W, An Y, Yang Y, Zhou Y, Zhang B, Lu D, Wang H, Qian J, Jin L. Common genetic variations of the cytochrome P450 1A1 gene and risk of hepatocellular carcinoma in a Chinese population. Eur J Cancer 2008; 45:1239-1247. [PMID: 19110417 DOI: 10.1016/j.ejca.2008.11.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 10/29/2008] [Accepted: 11/07/2008] [Indexed: 11/30/2022]
Abstract
Cytochrome P450 1A1 is a major enzyme in the bioactivation of exogenous procarcinogens of hepatocellular carcinoma (HCC). However, the contribution of common genetic variants in CYP1A1 to the HCC risk in Chinese populations has not been thoroughly investigated. In this study, we examined the association between HCC and four selected tagging single nucleotide polymorphisms (SNPs) of CYP1A1, and the risk of CYP1A1 haplotypes/diplotypes in 1006 pathologically confirmed HCC patients and 1015 cancer-free controls, from a Han Chinese population. Haplotypes/diplotypes were constructed from observed genotypes using the Haplo.Stats program. Relative risk was estimated by using multivariable logistic regression method. To summarise, we detected an increased HCC risk in rs4646421 variant carriers (OR 1.30, 95% CI 1.05-1.61) and rs2198843 variant carriers (OR 1.33, 95% CI 1.05-1.69), and a reduced risk of HCC (OR 0.70. 95% CI 0.52-0.94) associated with homozygote carriers of rs4886605 variant. These association signals were also observed in non-smokers with rs4646421 (OR 1.56, 95% CI 1.16-2.08) and rs4886605 (OR 0.61, 95% CI 0.40-0.91). Compared to the most common CYP1A1 haplotype CCAG, the haplotype TTGC conferred an increased risk of HCC (OR 1.26, 95% CI 1.04-1.52). Similarly, the TTGC/TTGC diplotype conferred an increased risk of HCC compared with diplotype CCAG/CCAG (OR 2.06, 95% CI 1.23-3.45, P=0.006). Interestingly, the diplotype TTAC/CCAG also conferred an increased risk of HCC (OR 1.76, 95% CI 1.22-2.54, P=0.003). Our results suggested that common genetic variants in CYP1A1 may modulate the risk of developing HCC in the study population, particularly in non-smokers. However, our findings need to be validated in at least one independent study of Han Chinese population.
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Affiliation(s)
- Rui Li
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, 220 Handan Rd., Shanghai 200433, PR China
| | - Yin Yao Shugart
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Weiping Zhou
- The Third Department of Hepatic Surgery, Eastern Hepatobiliary Surgery Hospital, Shanghai, PR China
| | - Yu An
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, 220 Handan Rd., Shanghai 200433, PR China
| | - Yuan Yang
- The Third Department of Hepatic Surgery, Eastern Hepatobiliary Surgery Hospital, Shanghai, PR China; International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, Shanghai, PR China
| | - Yun Zhou
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, Shanghai, PR China
| | - Beibei Zhang
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, Shanghai, PR China
| | - Daru Lu
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, 220 Handan Rd., Shanghai 200433, PR China
| | - Hongyang Wang
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, Shanghai, PR China.
| | - Ji Qian
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, 220 Handan Rd., Shanghai 200433, PR China.
| | - Li Jin
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, 220 Handan Rd., Shanghai 200433, PR China
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Minh SD, Below S, Müller C, Hildebrandt JP. Novel mammalian cell lines expressing reporter genes for the detection of environmental chemicals activating endogenous aryl hydrocarbon receptors (ArhR) or estrogen receptors (ER). Toxicol In Vitro 2008; 22:1935-47. [DOI: 10.1016/j.tiv.2008.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 08/11/2008] [Accepted: 09/08/2008] [Indexed: 11/25/2022]
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Singh V, Rastogi N, Sinha A, Kumar A, Mathur N, Singh MP. A Study on the Association of Cytochrome-P450 1A1 Polymorphism and Breast Cancer Risk in North Indian Women. Breast Cancer Res Treat 2006; 101:73-81. [PMID: 16807674 DOI: 10.1007/s10549-006-9264-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Accepted: 04/28/2006] [Indexed: 10/24/2022]
Abstract
Cytochrome P-450 1A1 (CYP1A1) is involved in the 2-hydroxylation of estrogens and mammary carcinogens into 2-hydroxy catechol metabolites. Many commonly occurring single nucleotide polymorphism (SNP) are reported in CYP1A1 in various populations that include, isoleucine to valine substitution at 462 codon in heme binding region in exon 7 (A to G transition at position 2455; M2), threonine to asparagine substitution at codon 461 (C to A transversion at position 2453; M4), T to C transition at 3801 position (M1) and T to C transition at position 3205 (M3) in 3' non-coding region. Epidemiological studies have shown inconsistent patterns between CYP1A1 polymorphism and breast cancer risk among various populations. Most of the studies have shown significant association between CYP1A1 genotype polymorphism and breast cancer risk. The present investigation was therefore undertaken to investigate the association of M1, M2, M3 and M4 polymorphisms and their subsequent contribution in premenopausal and postmenopausal women with breast cancer risk in north Indian women. Genomic DNA was isolated from case controls and breast cancer patients, specific segments of genomic DNA were amplified and restriction fragment length polymorphism (RFLP) was performed. CYP1A1 expression and catalytic activity were also assessed in premenopausal and postmenopausal case controls and patients. Polymorphism at M1, M2 and M4 alleles was detected and odds ratio for W/M1 and M1/M1 was calculated as 1.07 (95% CI, 0.59-1.87) and 0.74 (95% CI, 0.28-1.96) respectively. Odds ratio for W/M1 and M1/M1 alleles in premenopausal and postmenopausal women was 1.09 (95% CI, 0.45-2.49)/0.62 (95% CI, 0.10-2.66) and 1.60 (95% CI, 0.60-4.22)/1.06 (95% CI, 0.22-7.33) respectively. Odds ratio for W/M4 and M4/M4 allele was 1.20 (95% CI, 0.65-2.24)/4.55 (95% CI, 0.44-226.2) and 0.96 (95% CI, 0.36-2.64)/4.51 (95% CI, 0.23-273.0) respectively in total and premenopausal women. In postmenopausal women odds ratio was calculated as 1.16 (95% CI, 0.45-2.94) for M4/W but it could not be detected for M4/M4 since this genotype was not found in any postmenopausal case controls. Odds ratio for W/M2 genotype was calculated 0.57 (95% CI, 0.28-1.02), 1.06 (95% CI, 0.40-2.47) and 0.33 (95% CI, 0.12-0.89) respectively for total, premenopausal and postmenopausal women, however, in any group the odds ratio for M2/M2 could not be detected as M2/M2 genotype was not found in breast cancer patients. Polymorphism at M1 and M4 alleles was not found significantly associated with breast cancer risk and only wild type genotype was found in case controls and patients for M3 allele. Lack of protective association between CYP1A1 M2 genotype was also observed, however, in postmenopausal women a significant protective association with breast cancer risk was found (odds ratio, 0.33; 95% CI, 0.12-0.89; P-value 0.03). Similarly, no significant alteration in CYP1A1 expression and catalytic activity was observed in wild type and variant genotypes both in premenopausal and postmenopausal patients as compared with their respective controls. The results obtained from the present investigation thus suggest that probably CYP1A1 (M1, M2, M3, and M4) polymorphism alone does not play a significant role in the breast cancer risk in north Indian women.
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Affiliation(s)
- Virendra Singh
- Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Post Box 80, Lucknow, 226 001, UP, India
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Ueda R, Iketaki H, Nagata K, Kimura S, Gonzalez FJ, Kusano K, Yoshimura T, Yamazoe Y. A common regulatory region functions bidirectionally in transcriptional activation of the human CYP1A1 and CYP1A2 genes. Mol Pharmacol 2006; 69:1924-30. [PMID: 16505155 DOI: 10.1124/mol.105.021220] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The human CYP1A1 and CYP1A2 genes on chromosome 15 are orientated head-to-head and are separated by a 23-kilobase (kb) intergenic spacer region. Thus, the possibility exists for sharing common regulatory elements contained in the spacer region responsible for transcriptional activation and regulation of the CYP1A1 and CYP1A2 genes. In the present study, a reporter gene construct containing -22.4 kb of the 5'-flanking region of the CYP1A2 gene was found to support beta-naphthoflavone (BNF) and 3-methylchoranthrene (3-MC)-mediated transcriptional activation. The responsive region was also functional in directing activation of the CYP1A1 promoter, indicating that the region works bidirectionally to govern transcriptional activation of both CYP1A1 and CYP1A2. To simultaneously evaluate transcriptional activation of both genes, a dual reporter vector was developed in which the spacer region was inserted between two different reporter genes, firefly luciferase and secreted alkaline phosphatase. Transient transfection of the dual reporter vector in HepG2 cells revealed increases in both reporter activities after exposure of the cells to BNF and 3-MC. Deletion studies of the spacer region indicated that a region from -464 to -1829 of the CYP1A1 gene works bidirectionally to enhance the transcriptional activation of not only CYP1A1 but also CYP1A2. In addition, a negative bidirectional regulatory region was found to exist from -18,989 to -21,992 of the CYP1A1 gene. These data established that induction of human CYP1A1 and CYP1A2 is simultaneously controlled through bidirectional and common regulatory elements.
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Affiliation(s)
- Rika Ueda
- Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki-Aoba 6-3, Aoba-ku, Sendai 980-8578, Japan
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Masson LF, Sharp L, Cotton SC, Little J. Cytochrome P-450 1A1 gene polymorphisms and risk of breast cancer: a HuGE review. Am J Epidemiol 2005; 161:901-15. [PMID: 15870154 DOI: 10.1093/aje/kwi121] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cytochrome P-450 (CYP) 1A1 plays a key role in phase I metabolism of polycyclic aromatic hydrocarbons and in estrogen metabolism. It is expressed predominantly in extrahepatic tissues, including the breast. Four CYP1A1 gene polymorphisms (3801T --> C, Ile462Val, 3205T --> C, and Thr461Asp) have been studied in relation to breast cancer. The 3801C variant is more common than the Val variant. Both variants occur more frequently in Asians than in White populations. The 3205T --> C polymorphism has been observed in African Americans only. Little data are available on the geographic/ethnic distribution of the Thr461Asp polymorphism. The functional significance of the polymorphisms is unclear. In 17 studies, no consistent association between breast cancer and CYP1A1 genotype was found. Meta-analysis found no significant risk for the genotypes 1) 3801C/C (relative risk (RR) = 0.97, 95% confidence interval (CI): 0.52, 1.80) or 3801T/C (RR = 0.91, 95% CI: 0.70, 1.19) versus 3801T/T, 2) Val/Val (RR = 1.04, 95% CI: 0.63, 1.74) or Ile/Val (RR = 0.92, 95% CI: 0.76, 1.10) versus Ile/Ile, or 3) Asp/Asp (RR = 0.95, 95% CI: 0.20, 4.49) or Thr/Asp (RR = 1.12, 95% CI: 0.87, 1.43) versus Thr/Thr. Future studies should explore possible interactions between CYP1A1 and sources of polycyclic aromatic hydrocarbons, markers of estrogen exposure, other lifestyle factors influencing hormonal levels, and other genes involved in polycyclic aromatic hydrocarbon metabolism or hormonal biosynthesis.
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Affiliation(s)
- L F Masson
- Epidemiology Group, Department of Public Health, University of Aberdeen, Aberdeen, Scotland.
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Nioi P, Hayes JD. Contribution of NAD(P)H:quinone oxidoreductase 1 to protection against carcinogenesis, and regulation of its gene by the Nrf2 basic-region leucine zipper and the arylhydrocarbon receptor basic helix-loop-helix transcription factors. Mutat Res 2004; 555:149-71. [PMID: 15476858 DOI: 10.1016/j.mrfmmm.2004.05.023] [Citation(s) in RCA: 297] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 05/14/2004] [Accepted: 05/15/2004] [Indexed: 04/30/2023]
Abstract
NAD(P)H:quinone oxidoreductase 1 (NQO1) is a key enzyme involved in defence against reactive forms of oxygen and inhibition of neoplasia. Under conditions of oxidative stress, expression of NQO1 is induced, and the resulting increase in oxidoreductase protein provides the cell with multiple layers of protection against environmental insults. Firstly, the catalytic activity of NQO1 is directed towards the complete reduction and detoxication of highly reactive quinones. Secondly, the oxidoreductase maintains the endogenous lipid-soluble antioxidants, alpha-tocopherol-hydroquinone and ubiquinol in their reduced and active forms. Thirdly, NQO1 is required for the stabilisation of p53 protein in response to DNA-damaging stimuli, and it thereby influences cell fate decisions. In view of the anticarcinogenic actions of NQO1, an understanding of the mechanisms that govern its expression is desirable. The redox sensitivity of NQO1 transcription occurs through a cis-acting antioxidant response element (ARE) located within the regulatory region of the mouse, rat and human genes. This element recruits the positively acting basic leucine zipper (bZip) transcription factor NF-E2 p45-related factor 2 (Nrf2). Under normal constitutive conditions, Nrf2 associates with the cytoskeletal-binding protein Keap1, which regulates the subcellular distribution of the bZip factor and also targets it for proteasome-dependent degradation. Oxidative stress inhibits the Nrf2-Keap1 interaction, thus promoting nuclear accumulation of the transcription factor and transactivation of NQO1 and other ARE-driven genes. Mouse, rat and human NQO1 can also be induced by planar aromatic hydrocarbons through a cis-acting xenobiotic response element (XRE) located in their gene promoters. The XRE recruits the arylhydrocarbon receptor (AhR) and AhR nuclear translocator. Cross-talk may occur between Nrf2 and AhR, but the details of this process remain to be elucidated.
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Affiliation(s)
- Paul Nioi
- Biomedical Research Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
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15
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Marchand A, Barouki R, Garlatti M. Regulation of NAD(P)H:quinone oxidoreductase 1 gene expression by CYP1A1 activity. Mol Pharmacol 2004; 65:1029-37. [PMID: 15044633 DOI: 10.1124/mol.65.4.1029] [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: 02/03/2023] Open
Abstract
The dioxin 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD) induces phase I and II xenobiotic metabolizing enzymes (XME) which act sequentially to eliminate different classes of xenobiotics. The transcriptional effects of TCDD are generally mediated by the arylhydrocarbon receptor (AhR). We hypothesized that TCDD could also act indirectly, by increasing the activity of cytochrome P450 1A1 (CYP1A1), a phase I gene, which could then mediate the induction of other XME genes, such as the NAD(P)H:quinone oxidoreductase 1 (NQO1). To test this hypothesis, NQO1 gene expression was monitored after either overexpression of CYP1A1 or siRNA-mediated knock-down of CYP1A1 activity in the hepatoma cell line HepG2. Overexpression of CYP1A1 in the absence of TCDD was carried out using either adenoviral infection or the "Tet-off" system. Recombinant adenoviruses were produced encoding no protein, CYP1A1 (Ad1A1), or a mutated inactive CYP1A1 (Ad1A1mut). In the HepG2 Tet-off cell line, CYP1A1 expression was induced by the removal of doxycycline (dox) from the cell medium. Ad1A1 infection or dox removal induced CYP1A1 activity and H(2)O(2) production similarly to TCDD treatment. Moreover, in both systems, the amount of NQO1 mRNA increased to the same level as after TCDD treatment (approximately 2-fold). The UDP-glucuronosyl transferase 1A6 (UGT1A6) gene is also similarly regulated. NQO1 gene expression was not induced when mutant, inactive CYP1A1 was overexpressed or when the antioxidant N-acetyl cysteine (NAC) was added to Ad1A1. Finally, either NAC or siRNA directed against CYP1A1 mRNA decreased the induction of NQO1 gene expression by TCDD. We conclude that, after exposure to TCDD, the NQO1 gene expression can be controlled by CYP1A1 activity through an oxidative stress mediated pathway.
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Affiliation(s)
- A Marchand
- Institut National de la Santé et de la Recherche Médicale, Unité-490, 45 rue des Saints-Pères, 75006 Paris, France.
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16
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Gil L, Martínez V, Riquelme R, Ancic P, González G, Rodríguez L, Adonis M. Occupational and environmental levels of mutagenic PAHs and respirable particulate matter associated with diesel exhaust in Santiago, Chile. J Occup Environ Med 2004; 45:984-92. [PMID: 14506341 DOI: 10.1097/01.jom.0000085891.74340.5a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This work studied the mutagenic potential and polycyclic aromatic hydrocarbon (PAH) levels onto PM10 collected in diesel revision plants, in an urban area as well as in a rural area in Santiago, Chile. The PM10 average levels in diesel emission plants during working hours (there is no occupational PM10 Chilean standard) were significantly higher than the atmospheric Chilean PM10 standard and highly mutagenic and with high PAHs levels. Additionally, we evaluated the contribution of CYP1A1 and GSTM1 polymorphisms on 1-OH-pyrene urinary levels. The diesel-exposed workers carrying the CYP1A1*2A allele showed significantly higher 1-OH-P levels than the subjects from the rural area with the same genotype. The higher levels of 1-OH-P were found in individuals carrying the combined CYP1A1*2A and GSTM1 null genotype. This kind of information might be relevant to establish prevention, protection, and mitigation actions to protect public health.
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Affiliation(s)
- Lionel Gil
- Laboratorio de Bioquímica y Toxicología Ambiental, Facultad de Medicina, ICBM, Universidad de Chile, Santiago.
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17
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Acevedo C, Opazo JL, Huidobro C, Cabezas J, Iturrieta J, Quiñones Sepúlveda L. Positive correlation between single or combined genotypes of CYP1A1 and GSTM1 in relation to prostate cancer in Chilean people. Prostate 2003; 57:111-7. [PMID: 12949934 DOI: 10.1002/pros.10274] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The prostate cancer is a slowly progressing disease that begins decades prior to diagnosis. It has been suggested that there might be differences in susceptibility due to genetic polymorphisms in biotransformation enzyme genes. In the present work, associations between CYP1A1(Msp1), GSTM1(-/-) polymorphisms, and prostate cancer were analyzed in a case-control study. METHODS Genomic DNA was isolated from peripheral blood samples, collected on EDTA. PCR-RFLP was used to determine simultaneously Msp1 and GSTM1(-/-) polymorphisms. RESULTS In cancer patients, frequency of m2 variant allele (0.377) and GSTM1(-/-) (0.362) showed statistically significant increases compared to the control group (0.262 and 0.227, respectively). The estimate relative risks (OR) were higher for individuals carrying combined CYP1A1 and GSTM1 rare genotypes, in relation to individuals carrying CYP1A1 or GSTM1 alone. Multivariate logistic regression analysis including confounding factors (age, digital examination, and PSA antigen) showed even higher risk for individuals carrying m2m2 genotype (OR = 3.99; 95% CI, 1.27-12.54), GST(-/-) genotype (OR = 2.75; 95% CI, 1.31-5.79), and m2m2/GST(-) genotype (OR = 16.63; 95% CI, 1.67-165.48). CONCLUSIONS Taken together, these findings suggest that Chilean people carrying single or combined GSTM1 and CYP1A1 polymorphisms are more susceptible to prostate cancer.
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Affiliation(s)
- Cristian Acevedo
- Laboratory of Chemical Carcinogenesis and Pharmacogenetics, Programe of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
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18
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Kirton SB, Kemp CA, Tomkinson NP, St-Gallay S, Sutcliffe MJ. Impact of incorporating the 2C5 crystal structure into comparative models of cytochrome P450 2D6. Proteins 2002; 49:216-31. [PMID: 12211002 DOI: 10.1002/prot.10192] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cytochrome P450 2D6 (CYP2D6) metabolizes approximately one third of the drugs in current clinical use. To gain insight into its structure and function, we have produced four different sets of comparative models of 2D6: one based on the structures of P450s from four different microorganisms (P450 terp, P450 eryF, P450 cam, and P450 BM3), another on the only mammalian P450 (2C5) structure available, and the other two based on alternative amino acid sequence alignments of 2D6 with all five of these structures. Principal component analysis suggests that inclusion of the 2C5 crystal structure has a profound effect on the modeling process, altering the general topology of the active site, and that the models produced differ significantly from all of the templates. The four models of 2D6 were also used in conjunction with molecular docking to produce complexes with the substrates codeine and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP); this identified Glu 216 [in the F-helix; substrate recognition site (SRS) 2] as a key determinant in the binding of the basic moiety of the substrate. Our studies suggest that both Asp 301 and Glu 216 are required for metabolism of basic substrates. Furthermore, they suggest that Asp 301 (I-helix, SRS-4), a residue thought from mutagenesis studies to bind directly to the basic moiety of substrates, may play a key role in positioning the B'-C loop (SRS-1) and that the loss of activity on mutating Asp 301 may therefore be the result of an indirect effect (movement of the B'-C loop) on replacing this residue.
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Affiliation(s)
- Stewart B Kirton
- Department of Chemistry, University of Leicester, Leicester, United Kingdom
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19
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Szklarz GD, Paulsen MD. Molecular modeling of cytochrome P450 1A1: enzyme-substrate interactions and substrate binding affinities. J Biomol Struct Dyn 2002; 20:155-62. [PMID: 12354067 DOI: 10.1080/07391102.2002.10506831] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Human cytochrome P450 1A1, which is present in lungs, plays an important role in the metabolic activation of chemical carcinogens, and in particular, is thought to be linked to lung cancer. The mechanism of carcinogenesis is related to the enzyme's ability to oxidize highly toxic compounds, such as polycyclic aromatic hydrocarbons (PAHs), to their carcinogenic derivatives. In order to better understand P450 1A1 function, a homology model of this enzyme has been constructed. The model has been based on the structure of P450 2C5, the first mammalian P450 to be crystallized. The coordinates of the model have been calculated using a consensus strategy, and the resulting structure has been evaluated with the ProStat and Profiles-3D programs. P450 1A1 substrates, such as benzo[a]pyrene, ethoxyresorufin and methoxyresorufin, were then docked into the active site of the model, and key amino acid residues able to interact with the substrate, have been identified. The analysis of enzyme-substrate interactions indicated that hydrophobic interactions are mainly responsible for binding of these substrates in the active site. Moreover, the non-bond enzyme-substrate interaction energy for ethoxyresorufin was lower than that for methoxyresorufin, which is consistent with higher activity of 1A1 towards the former substrate. Key residue Val-382 may play an important role in these interactions. Additionally, we performed binding free energy calculations for the three substrates. The obtained values were similar to those observed experimentally, which suggests that this approach might be useful for prediction of binding constants.
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Affiliation(s)
- Grazyna D Szklarz
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV 26506-9530, USA.
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20
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Strichman-Almashanu LZ, Lee RS, Onyango PO, Perlman E, Flam F, Frieman MB, Feinberg AP. A genome-wide screen for normally methylated human CpG islands that can identify novel imprinted genes. Genome Res 2002; 12:543-54. [PMID: 11932239 PMCID: PMC187522 DOI: 10.1101/gr.224102] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
DNA methylation is a covalent modification of the nucleotide cytosine that is stably inherited at the dinucleotide CpG by somatic cells, and 70% of CpG dinucleotides in the genome are methylated. The exception to this pattern of methylation are CpG islands, CpG-rich sequences that are protected from methylation, and generally are thought to be methylated only on the inactive X-chromosome and in tumors, as well as differentially methylated regions (DMRs) in the vicinity of imprinted genes. To identify chromosomal regions that might harbor imprinted genes, we devised a strategy for isolating a library of normally methylated CpG islands. Most of the methylated CpG islands represented high copy number dispersed repeats. However, 62 unique clones in the library were characterized, all of which were methylated and GC-rich, with a GC content >50%. Of these, 43 clones also showed a CpG(obs)/CpG(exp) >0.6, of which 30 were studied in detail. These unique methylated CpG islands mapped to 23 chromosomal regions, and 12 were differentially methylated regions in uniparental tissues of germline origin, i.e., hydatidiform moles (paternal origin) and complete ovarian teratomas (maternal origin), even though many apparently were methylated in somatic tissues. We term these sequences gDMRs, for germline differentially methylated regions. At least two gDMRs mapped near imprinted genes, HYMA1 and a novel homolog of Elongin A and Elongin A2, which we term Elongin A3. Surprisingly, 18 of the methylated CpG islands were methylated in germline tissues of both parental origins, representing a previously uncharacterized class of normally methylated CpG islands in the genome, and which we term similarly methylated regions (SMRs). These SMRs, in contrast to the gDMRs, were significantly associated with telomeric band locations (P =.0008), suggesting a potential role for SMRs in chromosome organization. At least 10 of the methylated CpG islands were on average 85% conserved between mouse and human. These sequences will provide a valuable resource in the search for novel imprinted genes, for defining the molecular substrates of the normal methylome, and for identifying novel targets for mammalian chromatin formation.
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Affiliation(s)
- Liora Z Strichman-Almashanu
- Department of Medicine, Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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21
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NAKAMURO K, UENO H, OKUNO T, SAKAZAKI H, KAWAI H, KAMEI T, UGAWA M. Contribution of Endocrine-Disrupting Chemicals to Estrogenicity of Environmental Water. ACTA ACUST UNITED AC 2002. [DOI: 10.2965/jswe.25.355] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Quiñones L, Lucas D, Godoy J, Cáceres D, Berthou F, Varela N, Lee K, Acevedo C, Martínez L, Aguilera AM, Gil L. CYP1A1, CYP2E1 and GSTM1 genetic polymorphisms. The effect of single and combined genotypes on lung cancer susceptibility in Chilean people. Cancer Lett 2001; 174:35-44. [PMID: 11675150 DOI: 10.1016/s0304-3835(01)00686-3] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CYP1A1, CYP2E1 and GSTM1 polymorphisms were evaluated in Chilean healthy controls and lung cancer patients. In the Chilean healthy group, frequencies of CYP1A1 variant alleles for MspI (m2 or CYP1A1*2A) and ile/val (val or CYP1A1*2B) polymorphisms were 0.25 and 0.33, respectively. Frequencies of variant alleles C (CYP2E1*6) and c2 (CYP2E1*5B) for CYP2E1 were 0.21 and 0.16, respectively and frequency for GSTM1(-) was 0.24. The presence of variant alleles for GSTM1, MspI and Ile/val polymorphisms was more frequent in cases than in controls. However, frequencies for the c2 and C alleles were not significantly different in controls and in cases. The estimated relative risk for lung cancer associated to a single mutated allele in CYP1A1, CYP2E1 or GSTM1 was 2.41 for m2, 1.69 for val, 1.16 for C, 0.71 for c2 and 2.46 for GSTM1(-). The estimated relative risk was higher for individuals carrying combined CYP1A1 and GSTM1 mutated alleles (m2/val, OR=6.28; m2/GSTM1(-), OR=3.56) and lower in individuals carrying CYP1A1 and CYP2E1 mutated alleles (m2/C, OR=1.39; m2/c2, OR=2.00; val/C, OR=1.45; val/c2, OR=0.48; not significant). The OR values considering smoking were 4.37 for m2, 4.05 for val, 3.47 for GSTM1(-), 7.38 for m2/val and 3.68 for m2/GSTM1(-), higher values than those observed without any stratification by smoking. Taken together, these findings suggest that Chilean people carrying single or combined GSTM1 and CYP1A1 polymorphisms could be more susceptible to lung cancer induced by environmental pollutants such as polycyclic aromatic hydrocarbons.
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Affiliation(s)
- L Quiñones
- Faculty of Medicine, Laboratory of Environmental Toxicology and School of Public Health, University of Chile, Santiago, Chile
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23
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Corchero J, Pimprale S, Kimura S, Gonzalez FJ. Organization of the CYP1A cluster on human chromosome 15: implications for gene regulation. PHARMACOGENETICS 2001; 11:1-6. [PMID: 11207026 DOI: 10.1097/00008571-200102000-00001] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The sequence and organization of the CYP1A cluster on human chromosome 15 was determined. A human genomic clone from a BAC library, containing both CYP1A1 and CYP1A2 genes, was isolated and sequenced. The results of Southern blot analysis using human genomic DNA were compatible with the structure of the BAC clone. The CYP1A1 and CYP1A2 genes are separated by a 23 kb segment that contains no other open reading frames. The CYP1A1 and CYP1A2 genes are in opposite orientation, revealing that the 5' flanking region is in common between the two genes. Analysis of the sequence obtained revealed the presence of xenobiotic response elements (XREs) previously reported for CYP1A1 and CYP1A2 and several additional consensus sequences for putative XREs. The presence of all the XREs upstream of both genes suggest that some of the regulatory elements known to control CYP1A1 gene expression, could also control CYP1A2 gene expression.
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Affiliation(s)
- J Corchero
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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24
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Anttila S, Lei XD, Elovaara E, Karjalainen A, Sun W, Vainio H, Hankinson O. An uncommon phenotype of poor inducibility of CYP1A1 in human lung is not ascribable to polymorphisms in the AHR, ARNT, or CYP1A1 genes. PHARMACOGENETICS 2000; 10:741-51. [PMID: 11186136 DOI: 10.1097/00008571-200011000-00008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cigarette smoking can induce CYP1A1 in the lung. Induction requires the aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor nuclear translocator (ARNT) proteins. Lung samples from seven of 75 Finnish patients who smoked until the time of surgery exhibited absent or low levels of CYP1A1 protein, mRNA and enzymatic activity, suggesting that these individuals might be genetically non or poorly inducible for CYP1A1. All seven lung samples expressed normal levels of AHR mRNA and ARNT mRNA, indicating that they did not carry inactivating polymorphisms in the 5' upstream regulatory regions of these genes. Sequencing of cDNAs encompassing the complete coding regions of AHR and ARNT identified a previously known codon 554 polymorphism in AHR, which was present in the homozygous state in one individual. This polymorphism, which leads to an amino acid substitution, has previously been reported either to have no effect or to enhance CYP1A1 induction. Previously unreported silent single nucleotide polymorphisms were identified in codon 44 of AHR and codon 189 of ARNT. 1500 bp of genomic sequence from the 5' upstream regulatory sequence of the CYP1A1 gene was also sequenced in the non-inducible individuals. A nucleotide substitution polymorphism at position -459 was detected in the heterozygous state in two individuals. This polymorphic site does not reside in any known regulatory sequence. The complete CYP1A1 coding sequence and intron/exon boundaries were then sequenced. None of the non or poorly inducible individuals exhibited any polymorphisms, either homozygous or heterozygous compared to representative inducible individuals or the previously published CYP1A1 sequence. Thus, no polymorphisms in the AHR, ARNT or CYP1A1 genes were identified that could be responsible for the non/low inducibility phenotype observed.
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Affiliation(s)
- S Anttila
- Department of Pathology and Laboratory Medicine and Johnson Comprehensive Cancer Center, University of California, Los Angeles, USA
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25
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Linder MW, Falkner KC, Srinivasan G, Hines RN, Prough RA. Role of canonical glucocorticoid responsive elements in modulating expression of genes regulated by the arylhydrocarbon receptor. Drug Metab Rev 1999; 31:247-71. [PMID: 10065375 DOI: 10.1081/dmr-100101917] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- M W Linder
- Department of Biochemistry and Molecular Biology School of Medicine, University of Louisville, Kentucky 40292, USA
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26
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Bentivegna CS, Ihnat MA, Baptiste NS, Hamilton JW. Developmental regulation of the 3-methylcholanthrene- and dioxin-inducible CYP1A5 gene in chick embryo liver in vivo. Toxicol Appl Pharmacol 1998; 151:166-73. [PMID: 9705900 DOI: 10.1006/taap.1998.8439] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cDNA sequences for two dioxin-inducible cytochrome P450s in chicken, CYP1A4 and CYP1A5, have recently been reported which correspond to two dioxin-inducible forms of P450 previously designated as TCDDAHH and TCDDAA, respectively. The developmental expression of CYP1A4-associated aryl hydrocarbon (benzo[a]pyrene) hydroxylase (AHH) activity and its association with expression of the Ah receptor had previously been characterized in chick embryo liver. The purpose of this study was to examine the developmental regulation of the second dioxin-inducible P450 gene, CYP1A5, in chick embryo liver. A partial gene sequence for CYP1A5 indicated that the intron/exon organization of this gene was identical to that of the CYP1A1 and CYP1A2 mammalian genes and was present in a single copy in the genome. CYP1A5 mRNA was expressed basally in chick embryo liver and was highly inducible by the Ah receptor ligands, 3-methylcholanthrene, beta-naphthoflavone, and 3,4,3', 4'-tetrachlorobiphenyl (TCB), but not by the phenobarbital analog, glutethimide. CYP1A5 mRNA levels were increased 40- to 50-fold within 5 h after a single TCB treatment, corresponding to a 30- to 40-fold increase in the transcription rate of the CYP1A5 gene at this time point. In contrast to a previous report that CYP1A5 mRNA expression was inducible by estradiol, we observed no effects of estradiol or dexamethasone on CYP1A5 mRNA expression, either alone or in combination with TCB. Basal and TCB-inducible CYP1A5 mRNA expression was maximal in liver at 8 days of development and remained high throughout the remainder of embryonic development. Thus, CYP1A5 appears to be regulated in a very similar manner to CYP1A4 in chick embryo liver.
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Affiliation(s)
- C S Bentivegna
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire, 03755-3835, USA
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27
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Black VH, Wang AF, Henry M, Shaw PM. Induction of CYP1A1, but not CYP1A2, in adrenals of 3, 3'-methylcholanthrene-treated guinea pigs. Arch Biochem Biophys 1998; 354:197-205. [PMID: 9637727 DOI: 10.1006/abbi.1998.0636] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To test the inducibility of CYP1A homologs in guinea pig adrenal, the effects of 3,3'-methylcholanthrene, an archetypal inducer of CYP1A, were compared in guinea pig adrenal and liver. Western blot analysis showed that levels of both CYP1A1 (53 kDa) and CYP1A2 (56 kDa) increasedin liver microsomes of 3,3'-methylcholanthrene-treated guinea pigs. In adrenals, an immunoreactive protein comigrating with liver CYP1A1 was detected only after 3,3'-methylcholanthrene treatment. Protein comigrating with CYP1A2 was never detected in adrenal microsomes. A third inducible immunoreactive protein (57 kDa) was seen in liver, but not adrenal, after 3, 3'-methylcholanthrene treatment. Another immunoreactive protein (52 kDa), present constitutively in liver and adrenal microsomes, was not induced in either tissue by 3,3'-methylcholanthrene. The precise identities of the inducible 57-kDa and the noninducible 52-kDa proteins remain to be determined. However, the identity of the 53-kDa protein in the adrenal as CYP1A1 was confirmed by RT-PCR, Northern blot, and sequence analysis. Similar analyses demonstrated that, despite the fact that the 56-kDa protein was not detectable in adrenal microsomes, CYP1A2 mRNA was present in adrenals of control animals. Strikingly, CYP1A2 mRNA decreased in adrenal, but increased in liver, following 3,3'-methylcholanthrene treatment, underscoring differences in the regulation of CYP1A expression in the two tissues. Levels of ethoxyresorufin and methyoxyresorufin metabolism correlated with levels of CYP1A1 and CYP1A2 protein, respectively.
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Affiliation(s)
- V H Black
- Department of Cell Biology and Kaplan Cancer Center, New York University School of Medicine, New York, New York, 10016, USA.
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28
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Wei YD, Helleberg H, Rannug U, Rannug A. Rapid and transient induction of CYP1A1 gene expression in human cells by the tryptophan photoproduct 6-formylindolo[3,2-b]carbazole. Chem Biol Interact 1998; 110:39-55. [PMID: 9566724 DOI: 10.1016/s0009-2797(97)00111-7] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Studies to assess the induction of CYP1A1 gene expression by tryptophan derived oxidation products which are suggested as endogenous ligands for the Ah receptor are described. For the two high affinity Ah receptor ligands produced from tryptophan, the chemical structure was recently identified as 6-formylindolo[3,2-b]carbazole (FICZ) and 6,12-diformylindolo[3,2-b]carbazole (dFICZ), respectively. Therefore these two compounds show a close similarity to the indolecarbinol-derived condensation product indolo[3,2-b]carbazole (ICZ). Incubation of cells from a human keratinocyte (HaCaT) cell line together with ICZ, FICZ, dFICZ and some structurally related indole compounds was performed. The compound with the highest affinity to the Ah receptor, FICZ, was found to be the most efficient inducer of CYP1A1 gene expression in short time incubation (0.5 h) experiments. With longer incubation times (24 h) ICZ was the most efficient inducer. The two most active compounds, FICZ and ICZ, caused increased mRNA levels already at a concentration of 100 pM. FICZ was also shown to increase CYP1A1 mRNA levels in fresh human peripheral blood cells at the same low concentration. FICZ and ICZ were furthermore compared with regard to their capacity to inhibit cDNA-expressed human CYP1A1 enzyme and FICZ was found to be the most potent inhibitor. The inhibition was, however, transient in character indicating that FICZ is also an exceptionally good substrate for the CYP1A1 enzyme. The results showing the potent and transient effect of these formylindolocarbazoles, thus emphasize their important properties as signal substances in the Ah receptor pathway. This makes the most potent compound, FICZ, a good candidate for the endogenous ligand of the Ah receptor necessary for normal development and for the basal expression of Ah receptor-dependent genes.
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Affiliation(s)
- Y D Wei
- Department of Genetic and Cellular Toxicology, Stockholm University, Sweden
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29
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Falckh PH, Wu QK, Ahokas JP. CYP4T1--a cytochrome P450 expressed in rainbow trout (Oncorhynchus mykiss) liver. Biochem Biophys Res Commun 1997; 236:302-5. [PMID: 9240430 DOI: 10.1006/bbrc.1997.6957] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Total RNA isolated from a rainbow trout (Oncorhynchus mykiss) liver was subjected to RT/PCR using degenerate primers designed from homologous regions amongst cytochrome P450 CYP4 proteins. PCR amplification resulted in a single electrophoretic band which was excised, purified and sequenced directly, using cycle sequencing. The deduced protein sequence demonstrated the closest amino acid identity to rabbit CYP4B1 (54.6%) and rat CYP4B2 (55.4%). Phylogenic analysis of this sequence was found to be significantly different to any other CYP4 sequence and has been named CYP4T1. This represents the first CYP4 family member to be identified in an aquatic vertebrate.
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Affiliation(s)
- P H Falckh
- Key Centre for Applied and Nutritional Toxicology, RMIT-University, Melbourne, Australia.
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30
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Ourlin JC, Vilarem MJ, Daujat M, Harricane MC, Domergue J, Joyeux H, Baulieux J, Maurel P. Lipid-mediated transfection of normal adult human hepatocytes in primary culture. Anal Biochem 1997; 247:34-44. [PMID: 9126368 DOI: 10.1006/abio.1997.2025] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aim of this work was to develop a procedure for the lipid-mediated transfection of DNA into normal adult human hepatocytes in culture. Cells were plated in a serum-free culture medium at various cell densities, on plastic or collagen-coated dishes, both in the absence and in the presence of epidermal growth factor (EGF). The cells were incubated for various periods of time with mixtures of DNA-lipofectin or DNA-3 beta[N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-chol) liposomes, and the efficiency of transfection was assessed by measuring the activity of reporter genes, beta-galactosidase or chloramphenicol acetyl-transferase (CAT). For comparison, similar experiments were carried out with human cell lines including HepG2, Caco-2, and WRL68. The efficiency of transfection (in percentage of cells) was not significantly different after transfection with lipofectin or DC-chol and comprised between 0.04 and 1.7% (extreme values) for different cultures. The efficiency of transfection decreased as the age or density of the culture increased and increased in cultures treated with EGF. Direct measurement of the rate of DNA synthesis suggested that the efficiency of transfection was related to the number of cells entering the S phase. Under the same conditions, the efficiency of transfection was one to two orders of magnitude greater in the three cell lines. A plasmid harboring 660 bp of the 5'-flanking region of CYP1A1 (containing two xenobiotic enhancer elements) fused upstream of the promoter of thymidine kinase and the CAT reporter gene was constructed. When this plasmid was transfected in human hepatocytes, CAT activity was induced as expected. We conclude that normal adult human hepatocytes can be transfected with exogenous DNA and that the transfected construct is regulated in the manner expected from in vivo studies.
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31
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Walsh AA, Tullis K, Rice RH, Denison MS. Identification of a novel cis-acting negative regulatory element affecting expression of the CYP1A1 gene in rat epidermal cells. J Biol Chem 1996; 271:22746-53. [PMID: 8798449 DOI: 10.1074/jbc.271.37.22746] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Polycyclic aromatic hydrocarbons such as 3-methylcholanthrene are toxic to rat epidermal cells in low passages (3 to 6), but cultures of high passage (>/=15) are resistant. Since such compounds can be metabolically activated by cytochrome P4501A1, we have examined the regulation of this gene in low and high passage cells. Consistent with this difference, little or no 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible P4501A1 mRNA or enzyme activity was observed in high passage as compared to low passage cultures. Similarly, transfection of a luciferase reporter construct containing -1317 to +256 base pairs of the 5'-flanking region of the murine CYP1A1 gene was TCDD-inducible in low but not high passage cells. Ligand binding and transfection experiments demonstrated the presence of functional Ah receptor complexes in both high and low passage cells. Deletion analysis identified a 26-base pair negative regulatory DNA (NeRD) element contained within the upstream regulatory region of the CYP1A1 gene responsible for this effect. Nuclear extracts from both low and high passage cells contain a protein which specifically binds to NeRD-containing DNA. Thus, the loss of polycyclic aromatic hydrocarbon sensitivity in high passage rat epidermal cells appears to be due to decreased expression of CYP1A1, and this effect may be mediated by an altered NeRD binding factor(s) present in these cells.
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Affiliation(s)
- A A Walsh
- Department of Environmental Toxicology, University of California, Davis, California 95616-8588, USA
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32
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Daujat M, Charrasse S, Fabre I, Lesca P, Jounaïdi Y, Larroque C, Poellinger L, Maurel P. Induction of CYP1A1 gene by benzimidazole derivatives during Caco-2 cell differentiation. Evidence for an aryl-hydrocarbon receptor-mediated mechanism. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 237:642-52. [PMID: 8647108 DOI: 10.1111/j.1432-1033.1996.0642p.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The Caco-2 cell line, derived from a human colon adenocarcinoma, is unique in its property of spontaneously differentiating into a mature enterocyte cell type during its growth in culture. In this work, we compared the response of the CYP1A1 gene with the benzimidazole derivatives omeprazole and lansoprazole, and with the classical inducer beta-naphthoflavone in the Caco-2 cells at various culture stages. In addition, we characterized the Caco-2 aryl-hydrocarbon receptor. The protein-synthesis inhibitor cycloheximide led to a derepression of the CYP1A1 gene transcription, and to a superinduction when combined with either beta-naphthoflavone or benzimidazoles. Taking advantage of the spontaneous differentiation of Caco-2 cells in long-term cultures, we observed a difference in behavior between the classical inducer beta-naphthoflavone and the atypical inducer omeprazole. In the poorly differentiated cells, both compounds elicited comparable dose/response and rate of induction of CYP1A1 gene expression. In the fully differentiated cells, in contrast, the induction by omeprazole was only transient, whereas the response to beta-naphthoflavone was long lasting. The Caco-2 aryl-hydrocarbon receptor exhibited binding characteristics similar to those determined for human liver and other tissues. The induction of CYP1A1 transcription by benzimidazole derivatives in Caco-2 cells occurred with no direct binding of benzimidazole derivatives to the aryl-hydrocarbon receptor, as in human hepatocytes. However, transient transfection experiments clearly showed that the xenobiotic-responsive element enhancer, with which the activated aryl-hydrocarbon receptor interacts, could drive the induction of a heterologous promoter in the presence of benzimidazoles. Finally the presence of the activated aryl-hydrocarbon receptor in the nuclei of the Caco-2 cells exposed to these molecules was clearly demonstrated by gel-retardation experiments. These results question about the mechanism of ligand-independent activation of the aryl-hydrocarbon receptor and intracellular signaling, initiated by benzimidazole derivatives.
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Affiliation(s)
- M Daujat
- Unité 128 INSERM, CNRS, Montpellier, France
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33
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Kawajiri K, Watanabe J, Hayashi S. Identification of allelic variants of the human CYP1A1 gene. Methods Enzymol 1996; 272:226-32. [PMID: 8791781 DOI: 10.1016/s0076-6879(96)72027-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- K Kawajiri
- Department of Biochemistry, Saitama Cancer Center Research Institute, Japan
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34
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Oyama T, Mitsudomi T, Kawamoto T, Ogami A, Osaki T, Kodama Y, Yasumoto K. Detection of CYP1A1 gene polymorphism using designed RFLP and distributions of CYP1A1 genotypes in Japanese. Int Arch Occup Environ Health 1995; 67:253-6. [PMID: 7591186 DOI: 10.1007/bf00409407] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Isoleucine (Ile)-valine (Val) polymorphism, which is caused by a point mutation from A to G in exon 7, is reported to be associated with an elevated risk of lung cancer among Japanese. Because CYP1A1 catalyzes bioactivation of environmental procarcinogens, such as benzo[a]pyrene, it is very important to study the clinical meaning of Ile-Val polymorphism using an epidemiological study. In an epidemiological study, easy, economical, rapid and reliable identification of the CYP1A1 genotype is necessary. The present study shows that the new method, designed restriction fragment length polymorphism (designed RFLP), can detect Ile-Val polymorphism of CYP1A1. The Ile-Val polymorphism detected using this new method was consistent with that found by the allele-specific PCR amplifications (ASA) method in six cases tested. This new method detected Ile-Val polymorphism of CYP1A1 using 240 healthy Japanese who lived in the northern Kyusyu region. The frequency of the genotypes was as follows: Ile/Ile 159 (66.2%); Ile/Val, 65 (27.1%); Val/Val, 16 (6.7%). The frequency of the Ile gene was 0.798 and that of the Val gene, 0.202. There was no difference in Ile-Val polymorphism based on sex or age. Racial differences influenced the distribution of this polymorphism, but Japanese regional differences did not. Since this new method, designed RFLP, is rapid, reliable and suitable for large-scale screening of polymorphisms, it may be used routinely to detect Ile-Val polymorphism of CYP1A1. Furthermore, it will help to evaluate the relationship between CYP1A1 polymorphism and individual sensitivity to xenobiotics that may affect the incidence of lung cancer.
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Affiliation(s)
- T Oyama
- Department of Surgery II, University of Occupational and Environmental Health, Kitakyushu, Japan
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35
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Crespi CL. Xenobiotic-metabolizing human cells as tools for pharmacological and toxicological research. ADVANCES IN DRUG RESEARCH VOLUME 26 1995. [DOI: 10.1016/s0065-2490(05)80006-1] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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36
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Fukuda Y, Sassa S. Suppression of cytochrome P450IA1 by interleukin-6 in human HepG2 hepatoma cells. Biochem Pharmacol 1994; 47:1187-95. [PMID: 8161348 DOI: 10.1016/0006-2952(94)90391-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The effects of interleukin-6 (IL-6), the major inducer of the acute-phase reaction, on the expression of cytochrome P450IA1 (CYPIA1) were examined using human HepG2 hepatoma cells. Treatment of cells with IL-6 decreased the level of 3-methylcholanthrene-induced CYPIA1 protein and its mRNA. Nuclear runoff analysis revealed that the effect of IL-6 was largely transcriptional. IL-6 treatment of HepG2 cells increased mRNA for microsomal heme oxygenase, the rate-limiting enzyme in heme catabolism, suggesting that the suppressive effect of IL-6 on CYPIA1 mRNA may be due to a loss of heme. Consistent with this hypothesis, simultaneous treatment of cells with Sn-mesoporphyrin, an inhibitor of heme oxygenase, prevented the IL-6-mediated suppression of CYPIA1. These findings suggest that the suppression of P450IA1 mRNA by IL-6 appears to occur, at least in part, from the decline in free heme content as a result of the induction of heme oxygenase. Our results raise the possibility that other physiological as well as environmental stimuli which affect cellular heme concentrations may also modulate the expression of P450s.
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Affiliation(s)
- Y Fukuda
- Rockefeller University, New York, NY 10021
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37
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Shen L, Wu L, Sanlioglu S, Chen R, Mendoza A, Dangel A, Carroll M, Zipf W, Yu C. Structure and genetics of the partially duplicated gene RP located immediately upstream of the complement C4A and the C4B genes in the HLA class III region. Molecular cloning, exon-intron structure, composite retroposon, and breakpoint of gene duplication. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37217-4] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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38
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Eugster HP, Sengstag C. Saccharomyces cerevisiae: an alternative source for human microsomal liver enzymes and its use in drug interaction studies. Toxicology 1993; 82:61-73. [PMID: 8236282 DOI: 10.1016/0300-483x(93)90060-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Heterologous expression of human cDNAs in the yeast Saccharomyces cerevisiae represents an attractive alternative source of human enzymes and allows metabolic studies to be performed without the need of human tissue. Here we report on the functional expression of human microsomal epoxide hydrolase (hmEH) and cytochrome P450 1A1 and 1A2 in yeast. Microsomal fractions of corresponding yeast strains exhibited enzyme specific activities which allowed the characterization of the heterologous enzymes. The use of these microsomes enabled us to study drug interactions on the respective enzymes with pharmacologically relevant drugs such as carbamazepine epoxide, valpromide and ketoconazole.
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Affiliation(s)
- H P Eugster
- Institute of Toxicology, Swiss Federal Institute of Technology, Schwerzenbach
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39
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Kikuta Y, Kusunose E, Endo K, Yamamoto S, Sogawa K, Fujii-Kuriyama Y, Kusunose M. A novel form of cytochrome P-450 family 4 in human polymorphonuclear leukocytes. cDNA cloning and expression of leukotriene B4 omega-hydroxylase. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)98360-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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40
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Kawajiri K, Nakachi K, Imai K, Watanabe J, Hayashi S. The CYP1A1 gene and cancer susceptibility. Crit Rev Oncol Hematol 1993; 14:77-87. [PMID: 8103989 DOI: 10.1016/1040-8428(93)90007-q] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A close correlation between cigarette smoking associated lung cancer incidence and an Msp I restriction fragment length polymorphism (RFLP) of the human P-450 1A1 (CYP1A1) gene was found in a Japanese population in terms of genotype frequency and cigarette dose. A Val/Ile codon difference in the primary structure of the CYP1A1 protein (Val-, Ile-type) was in linkage disequilibrium with the Msp I RFLP. A synergistic increase in susceptibility to lung cancer was found when combining genotyping of CYP1A1 and the Mu-class of glutathione S-transferase (GST1). Interindividual variability in the genetic make-up of carcinogen metabolizing enzymes may thus be a key host factor to explain the differences in susceptibility to chemical carcinogenesis among individuals.
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Affiliation(s)
- K Kawajiri
- Department of Biochemistry, Saitama Cancer Center Research Institute, Japan
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41
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Cross-coupling of signal transduction pathways: the dioxin receptor mediates induction of cytochrome P-450IA1 expression via a protein kinase C-dependent mechanism. Mol Cell Biol 1993. [PMID: 8380231 DOI: 10.1128/mcb.13.1.677] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Signal transduction by dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) is mediated by the intracellular dioxin receptor which, in its dioxin-activated state, regulates transcription of target genes encoding drug-metabolizing enzymes, such as cytochrome P-450IA1 and glutathione S-transferase Ya. Exposure of the dioxin receptor to dioxin leads to an apparent translocation of the receptor to the nucleus in vivo and to a rapid conversion of the receptor from a latent, non-DNA-binding form to a species that binds to dioxin-responsive positive control elements in vitro. This DNA-binding form of receptor appears to be a heterodimeric complex with the helix-loop-helix factor Arnt. In this study, we show that activation of the cytochrome P-450IA1 gene and minimal dioxin-responsive reporter constructs by the dioxin receptor was inhibited following prolonged treatment of human keratinocytes with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate. Inhibition of the receptor-mediated activation response was also achieved by treatment of the cells with a number of protein kinase inhibitors, one of which, calphostin C, shows selectivity for protein kinase C. Taken together, these data suggest that protein kinase C-dependent phosphorylation may play an essential role in the dioxin signaling pathway. This hypothesis is supported by the observation that pretreatment of the cells with 12-O-tetradecanoylphorbol-13-acetate inhibited the DNA-binding activity of the dioxin receptor in vivo. In vivo, the dioxin receptor was found to be a phosphoprotein. In vitro, dephosphorylation of the ligand-activated, heteromeric dioxin receptor form or dephosphorylation of the individual ligand-binding and Arnt receptor subunits inhibited the xenobiotic response element-binding activity. Moreover, dephosphorylation experiments with the individual receptor subunits prior to assembly of the xenobiotic response element-binding receptor form indicated that phosphorylation seemed to be important for the DNA-binding activity per se of the receptor, whereas Arnt appeared to require phosphorylation to interact with the receptor. Finally, a protein kinase C inhibitor-sensitive cytosolic catalytic activity that could restore the DNA-binding activity of the dephosphorylated dioxin receptor form was identified.
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42
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Gautier JC, Urban P, Beaune P, Pompon D. Engineered yeast cells as model to study coupling between human xenobiotic metabolizing enzymes. Simulation of the two first steps of benzo[a]pyrene activation. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 211:63-72. [PMID: 8425552 DOI: 10.1111/j.1432-1033.1993.tb19870.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Human microsomal epoxide hydrolase and cytochrome P450 (P450) 1A1 were coexpressed in Saccharomyces cerevisiae from expression cassettes integrated respectively into the host chromosomal DNA and on a multicopy plasmid in a strain already overexpressing yeast NADPH-cytochrome P450 reductase (P450 reductase). A styrene-oxide-hydrolase activity (2 nmol.min-1.mg microsomal protein-1) and a 7-ethoxyresorufin-O-deethylase activity (320 pmol.min-1.mg microsomal protein-1) characteristic respectively of microsomal epoxide hydrolase and P450 1A1 were detected. The conversion of benzo[a]pyrene (B[a]P) to B[a]P-7,8-dihydrodiol both in microsomal preparations and in growing yeast cells was observed, demonstrating an efficient coupling between the two human enzymes. Kinetic analysis indicated that the B[a]P-7,8-oxide produced by the P450-1A1-dependent reaction does not accumulate before hydrolysis by microsomal epoxide hydrolase. This system was also used as a control to evaluate the coupling efficiency of a mixture of microsomes or of yeast cells containing separately the individual enzymes (i.e., human P450 1A1 and microsomal epoxide hydrolase). B[a]P-7,8-oxide was well converted to the corresponding dihydrodiol with a mixture of microsomes. In contrast, when the same experiment was repeated with a mixture of cells expressing independently the two activities, dihydrodiol formation was not observed. Coexpression of human phase I and phase II enzymes in a single yeast cell and microsome mixture thus appear to be complementary tools for the simulation of human-drug-metabolism or carcinogen-metabolism pathways.
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Affiliation(s)
- J C Gautier
- Institut National de la Recherche Scientifique U75, CHU Necker-Enfants-Malades, Paris, France
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43
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Nelson DR, Kamataki T, Waxman DJ, Guengerich FP, Estabrook RW, Feyereisen R, Gonzalez FJ, Coon MJ, Gunsalus IC, Gotoh O. The P450 superfamily: update on new sequences, gene mapping, accession numbers, early trivial names of enzymes, and nomenclature. DNA Cell Biol 1993; 12:1-51. [PMID: 7678494 DOI: 10.1089/dna.1993.12.1] [Citation(s) in RCA: 1090] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We provide here a list of 221 P450 genes and 12 putative pseudogenes that have been characterized as of December 14, 1992. These genes have been described in 31 eukaryotes (including 11 mammalian and 3 plant species) and 11 prokaryotes. Of 36 gene families so far described, 12 families exist in all mammals examined to date. These 12 families comprise 22 mammalian subfamilies, of which 17 and 15 have been mapped in the human and mouse genome, respectively. To date, each subfamily appears to represent a cluster of tightly linked genes. This revision supersedes the previous updates [Nebert et al., DNA 6, 1-11, 1987; Nebert et al., DNA 8, 1-13, 1989; Nebert et al., DNA Cell Biol. 10, 1-14 (1991)] in which a nomenclature system, based on divergent evolution of the superfamily, has been described. For the gene and cDNA, we recommend that the italicized root symbol "CYP" for human ("Cyp" for mouse), representing "cytochrome P450," be followed by an Arabic number denoting the family, a letter designating the subfamily (when two or more exist), and an Arabic numeral representing the individual gene within the subfamily. A hyphen should precede the final number in mouse genes. "P" ("p" in mouse) after the gene number denotes a pseudogene. If a gene is the sole member of a family, the subfamily letter and gene number need not be included. We suggest that the human nomenclature system be used for all species other than mouse. The mRNA and enzyme in all species (including mouse) should include all capital letters, without italics or hyphens. This nomenclature system is identical to that proposed in our 1991 update. Also included in this update is a listing of available data base accession numbers for P450 DNA and protein sequences. We also discuss the likelihood that this ancient gene superfamily has existed for more than 3.5 billion years, and that the rate of P450 gene evolution appears to be quite nonlinear. Finally, we describe P450 genes that have been detected by expressed sequence tags (ESTs), as well as the relationship between the P450 and the nitric oxide synthase gene superfamilies, as a likely example of convergent evolution.
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Affiliation(s)
- D R Nelson
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill 27599
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44
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Berghard A, Gradin K, Pongratz I, Whitelaw M, Poellinger L. Cross-coupling of signal transduction pathways: the dioxin receptor mediates induction of cytochrome P-450IA1 expression via a protein kinase C-dependent mechanism. Mol Cell Biol 1993; 13:677-89. [PMID: 8380231 PMCID: PMC358946 DOI: 10.1128/mcb.13.1.677-689.1993] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Signal transduction by dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) is mediated by the intracellular dioxin receptor which, in its dioxin-activated state, regulates transcription of target genes encoding drug-metabolizing enzymes, such as cytochrome P-450IA1 and glutathione S-transferase Ya. Exposure of the dioxin receptor to dioxin leads to an apparent translocation of the receptor to the nucleus in vivo and to a rapid conversion of the receptor from a latent, non-DNA-binding form to a species that binds to dioxin-responsive positive control elements in vitro. This DNA-binding form of receptor appears to be a heterodimeric complex with the helix-loop-helix factor Arnt. In this study, we show that activation of the cytochrome P-450IA1 gene and minimal dioxin-responsive reporter constructs by the dioxin receptor was inhibited following prolonged treatment of human keratinocytes with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate. Inhibition of the receptor-mediated activation response was also achieved by treatment of the cells with a number of protein kinase inhibitors, one of which, calphostin C, shows selectivity for protein kinase C. Taken together, these data suggest that protein kinase C-dependent phosphorylation may play an essential role in the dioxin signaling pathway. This hypothesis is supported by the observation that pretreatment of the cells with 12-O-tetradecanoylphorbol-13-acetate inhibited the DNA-binding activity of the dioxin receptor in vivo. In vivo, the dioxin receptor was found to be a phosphoprotein. In vitro, dephosphorylation of the ligand-activated, heteromeric dioxin receptor form or dephosphorylation of the individual ligand-binding and Arnt receptor subunits inhibited the xenobiotic response element-binding activity. Moreover, dephosphorylation experiments with the individual receptor subunits prior to assembly of the xenobiotic response element-binding receptor form indicated that phosphorylation seemed to be important for the DNA-binding activity per se of the receptor, whereas Arnt appeared to require phosphorylation to interact with the receptor. Finally, a protein kinase C inhibitor-sensitive cytosolic catalytic activity that could restore the DNA-binding activity of the dephosphorylated dioxin receptor form was identified.
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Affiliation(s)
- A Berghard
- Center for Biotechnology, Karolinska Institute, Huddinge, Sweden
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45
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Lewis DF, Moereels H. The sequence homologies of cytochromes P-450 and active-site geometries. J Comput Aided Mol Des 1992; 6:235-52. [PMID: 1517776 DOI: 10.1007/bf00123379] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The amino acid sequence alignment of 16 cytochrome P-450 proteins representative of the major families is reported. The sequence matching process has been carried out on the basis of maximum homology by residue type, retention of secondary structure and minimization of deletions/insertions except where additional loop regions exist. From the starting point of known reported sequence homology matching from the literature, a realignment on the basis of conserved residues involved in both structure and function gives rise to a self-consistent set of sequences which correlates with known mechanistic and structural data. Once fitted, these archetypal sequences form a straightforward template for the alignment of all P-450 subfamilies. Computer modelling of the active-site regions constructed from homology with the bacterial form of the enzyme (P-450CAM) evinces the correct substrate specificity. Furthermore, the construction of the macromolecular assembly of components of the cytochrome P-450 system on the microsomal endoplasmic reticular membrane is presented from the evidence of site-directed mutagenesis, analysis by molecular probes, X-ray crystallography and molecular modelling.
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Affiliation(s)
- D F Lewis
- Department of Biochemistry, University of Surrey, Guildford, U.K
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Strom DK, Postlind H, Tukey RH. Characterization of the rabbit CYP1A1 and CYP1A2 genes: developmental and dioxin-inducible expression of rabbit liver P4501A1 and P4501A2. Arch Biochem Biophys 1992; 294:707-16. [PMID: 1567227 DOI: 10.1016/0003-9861(92)90745-i] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In adult rabbits, the CYP1A1 and CYP1A2 genes are expressed constitutively. Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) leads to elevations in both CYP1A1 and CYP1A2 gene products (S. T. Okino et al., 1985, Proc. Natl. Acad. Sci. USA 82, 5310-5314). In this report, we have characterized the rabbit CYP1A1 and CYP1A2 genes, and analyzed the pattern of expression of these genes in neonatal animals following exposure to TCDD. Genomic clones encoding the entire rabbit CYP1A1 and CYP1A2 genes were characterized. Restriction enzyme analysis and partial DNA sequence analysis identified the seven exons for the CYP1A1 and CYP1A2 genes. Primer extension analysis using mRNA from TCDD-treated neonatal rabbits helped confirm the start of transcription for the CYP1A genes. The length of the noncoding first exon of the CYP1A1 gene was 74 bases, compared to 90 and 88 bases for the human and rodent CYP1A1 genes. The length of the noncoding CYP1A2 gene first exon was 53 bases, similar to its counterpart in human and rodents. DNA sequence analysis of the 5' regulatory regions and comparison to the rodent and human CYP1 genes demonstrated that the rabbit CYP1A1 and CYP1A2 genes were most similar to their human orthologs. The 5' region of the CYP1A1 gene contained several consensus dioxin (Ah)-receptor responsive elements (XREs), while no functional XRE sequences were identified in the CYP1A2 gene. When expression of the two genes were monitored, a small amount of constitutive P4501A1 mRNA was detected in neonatal rabbits from the ages of 1 to 17 days, while P4501A2 mRNA levels could not be observed until 8-12 days postpartum. In response to TCDD treatment, P4501A1 mRNA levels were inducible at all neonatal time points, while P4501A2 mRNA levels could not be induced until the animals were 3-5 days postpartum. While the dioxin Ah-receptor most likely plays a major role in the induction of these genes by TCDD, early expression of the CYP1A1 and CYP1A2 genes is differentially regulated in a developmental fashion.
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Affiliation(s)
- D K Strom
- Department of Medicine, University of California, San Diego, La Jolla 92093-0812
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Fukuda Y, Ishida N, Noguchi T, Kappas A, Sassa S. Interleukin-6 down regulates the expression of transcripts encoding cytochrome P450 IA1, IA2 and IIIA3 in human hepatoma cells. Biochem Biophys Res Commun 1992; 184:960-5. [PMID: 1374245 DOI: 10.1016/0006-291x(92)90684-d] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Effects of human interleukin-6 (hIL-6), the major acute phase inducer, on the expression of transcripts encoding cytochrome P450s were examined in human hepatoma-derived cells. Using reverse-transcription polymerase chain reaction, it was demonstrated that three hepatoma cell lines, HepG2, HepG2f and Hep3B, express P450 mRNAs encoding IA1, IA2 and IIIA3, the major P450 isozymes involved in carcinogen metabolism, and that they also show induction responses to treatment with their specific inducers. When hepatoma cells were treated with hIL-6, the levels of IA1, IA2 and IIIA3 mRNAs were markedly suppressed. These findings suggest that significant down regulation of cytochrome P450s may occur during the acute phase reaction, which may result in alterations in drug biotransformation.
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Affiliation(s)
- Y Fukuda
- Rockefeller University, New York, N.Y. 10021
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Soucek P, Gut I. Cytochromes P-450 in rats: structures, functions, properties and relevant human forms. Xenobiotica 1992; 22:83-103. [PMID: 1615711 DOI: 10.3109/00498259209053106] [Citation(s) in RCA: 163] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- P Soucek
- Institute of Hygiene and Epidemiology, Department of Occupation Health, Praha, Czechoslovakia
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Abstract
Most of the chemical carcinogens in our environment are activated mainly by a restricted number of cytochrome P450 species, P450 1A1, 1A2, 2E1, and 3A. This metabolic activation of procarcinogens is a crucial part of the initial host response to the environmental exposure, since most chemical carcinogens do not show any carcinogenicity by themselves. Inter-individual variability in the metabolic activity may thus be a key host factor to explain the differences in susceptibility to chemical carcinogenesis among individuals. Recent studies on P450s in cancer etiology have provided some valuable insights into this problem.
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Affiliation(s)
- K Kawajiri
- Department of Biochemistry, Saitama Cancer Center Research Institute
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Bohm S. Identification of protein-binding sequences mediating constitutive and 12-O-tetradecanoylphorbol-13-acetate-induced VL30 transcription in cultured mouse and human keratinocytes. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54304-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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