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Cronin JM, Yu AM. Recombinant Technologies Facilitate Drug Metabolism, Pharmacokinetics, and General Biomedical Research. Drug Metab Dispos 2023; 51:685-699. [PMID: 36948592 PMCID: PMC10197202 DOI: 10.1124/dmd.122.001008] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 03/24/2023] Open
Abstract
The development of safe and effective medications requires a profound understanding of their pharmacokinetic (PK) and pharmacodynamic properties. PK studies have been built through investigation of enzymes and transporters that drive drug absorption, distribution, metabolism, and excretion (ADME). Like many other disciplines, the study of ADME gene products and their functions has been revolutionized through the invention and widespread adoption of recombinant DNA technologies. Recombinant DNA technologies use expression vectors such as plasmids to achieve heterologous expression of a desired transgene in a specified host organism. This has enabled the purification of recombinant ADME gene products for functional and structural characterization, allowing investigators to elucidate their roles in drug metabolism and disposition. This strategy has also been used to offer recombinant or bioengineered RNA (BioRNA) agents to investigate the posttranscriptional regulation of ADME genes. Conventional research with small noncoding RNAs such as microRNAs (miRNAs) and small interfering RNAs has been dependent on synthetic RNA analogs that are known to carry a range of chemical modifications expected to improve stability and PK properties. Indeed, a novel transfer RNA fused pre-miRNA carrier-based bioengineering platform technology has been established to offer consistent and high-yield production of unparalleled BioRNA molecules from Escherichia coli fermentation. These BioRNAs are produced and processed inside living cells to better recapitulate the properties of natural RNAs, representing superior research tools to investigate regulatory mechanisms behind ADME. SIGNIFICANCE STATEMENT: This review article summarizes recombinant DNA technologies that have been an incredible boon in the study of drug metabolism and PK, providing investigators with powerful tools to express nearly any ADME gene products for functional and structural studies. It further overviews novel recombinant RNA technologies and discusses the utilities of bioengineered RNA agents for the investigation of ADME gene regulation and general biomedical research.
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Affiliation(s)
- Joseph M Cronin
- Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, CA (J.M.C., A.-M.Y.)
| | - Ai-Ming Yu
- Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, CA (J.M.C., A.-M.Y.)
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CYP2E1 in Alcoholic and Non-Alcoholic Liver Injury. Roles of ROS, Reactive Intermediates and Lipid Overload. Int J Mol Sci 2021; 22:ijms22158221. [PMID: 34360999 PMCID: PMC8348366 DOI: 10.3390/ijms22158221] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 02/08/2023] Open
Abstract
CYP2E1 is one of the fifty-seven cytochrome P450 genes in the human genome and is highly conserved. CYP2E1 is a unique P450 enzyme because its heme iron is constitutively in the high spin state, allowing direct reduction of, e.g., dioxygen, causing the formation of a variety of reactive oxygen species and reduction of xenobiotics to toxic products. The CYP2E1 enzyme has been the focus of scientific interest due to (i) its important endogenous function in liver homeostasis, (ii) its ability to activate procarcinogens and to convert certain drugs, e.g., paracetamol and anesthetics, to cytotoxic end products, (iii) its unique ability to effectively reduce dioxygen to radical species causing liver injury, (iv) its capability to reduce compounds, often generating radical intermediates of direct toxic or indirect immunotoxic properties and (v) its contribution to the development of alcoholic liver disease, steatosis and NASH. In this overview, we present the discovery of the enzyme and studies in humans, 3D liver systems and genetically modified mice to disclose its function and clinical relevance. Induction of the CYP2E1 enzyme either by alcohol or high-fat diet leads to increased severity of liver pathology and likelihood to develop ALD and NASH, with subsequent influence on the occurrence of hepatocellular cancer. Thus, fat-dependent induction of the enzyme might provide a link between steatosis and fibrosis in the liver. We conclude that CYP2E1 has many important physiological functions and is a key enzyme for hepatic carcinogenesis, drug toxicity and liver disease.
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Hu YH, Li DK, Quan ZY, Wang CY, Zhou M, Sun ZX. Exploration of components and mechanisms of Polygoni Multiflori Radix-induced hepatotoxicity using siRNA -mediated CYP3A4 or UGT1A1 knockdown liver cells. JOURNAL OF ETHNOPHARMACOLOGY 2021; 270:113845. [PMID: 33485974 DOI: 10.1016/j.jep.2021.113845] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/10/2021] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Polygoni Multiflori Radix, the dried root of Polygonum multiflorum Thunb., and its processed products have been used as restoratives for centuries in China. However, the reports of Polygoni Multiflori Radix-induced liver injury (PMR-ILI) have received wide attention in recent years, and the components and mechanism of PMR-ILI are not completely clear yet. Our previous studies found that the PMR-ILI was related to the down-regulation of some drug metabolism enzymes (DME). AIM OF THE STUDY To explore the effect of the inhibition of CYP3A4 or UGT1A1 on PMR-ILI, screen the relevant hepatotoxic components and unveil its mechanism. METHODS RT-qPCR was used to detect the effects of water extract of Polygoni Multiflori Radix (PMR) and its main components on the mRNA expression of CYP3A4 and UGT1A1 in human hepatic parenchyma cell line L02. High-performance liquid chromatography (HPLC) was employed to detect the content of major components in the PMR. And then, the stable CYP3A4 or UGT1A1 knockdown cells were generated using short hairpin RNAs (shRNA) in L02 and HepaRG cells. Hepatotoxic components were identified by cell viability assay when PMR and its four representative components, 2,3,5,4'-tetrahydroxy stilbene glycoside (TSG), emodin (EM), emodin-8-O-β-D-glucoside (EG), and gallic acid (GA), acted on CYP3A4 or UGT1A1 knockdown cell lines. The PMR-ILI mechanism of oxidative stress injury and apoptosis in L02 and HepaRG cells were detected by flow cytometry. Finally, the network toxicology prediction analysis was employed to excavate the targets of its possible toxic components and the influence on the metabolic pathway. RESULTS PMR and EM significantly inhibited the mRNA expression of CYP3A4 and UGT1A1 in L02 cells, while TSG and GA activated the mRNA expression of CYP3A4 and UGT1A1, and EG activated CYP3A4 expression while inhibited UGT1A1 expression. The contents of TSG, EG, EM and GA were 34.93 mg/g, 1.39 mg/g, 0.43 mg/g and 0.44 mg/g, respectively. The CYP3A4 or UGT1A1 knockdown cells were successfully constructed in both L02 and HepaRG cells. Low expression of CYP3A4 or UGT1A1 increased PMR cytotoxicity remarkably. Same as PMR, the toxicity of EM and GA increased in shCYP3A4 and shUGT1A1 cells, which suggested EM and GA may be the main components of hepatotoxicity in PMR. Besides, EM not only inhibited the expression of metabolic enzymes but also reduced the cytotoxicity threshold. EM and GA affected the level of ROS, mitochondrial membrane potential, Ca2+ concentration, and dose-dependent induced hepatocyte apoptosis in L02 and HepaRG cells. The network toxicology analysis showed that PMR-ILI was related to drug metabolism-cytochrome P450, glutathione metabolism, and steroid hormone biosynthesis. CONCLUSION The inhibition of mRNA expression of CYP3A4 or UGT1A1 enhanced hepatotoxicity of PMR. EM and GA, especially EM, may be the main hepatotoxic components in PMR. The mechanism of PMR, EM and GA induced hepatotoxicity was proved to be related to elevated levels of ROS, mitochondrial membrane potential, Ca2+ concentration, and induction of apoptosis in liver cells.
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Affiliation(s)
- Ying-Huan Hu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, China.
| | - Deng-Ke Li
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Zheng-Yang Quan
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Cheng-Yu Wang
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Ming Zhou
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Zhen-Xiao Sun
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, China.
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Wang T, Du H, Ma J, Shen L, Wei M, Zhao X, Chen L, Li M, Li G, Xing Q, He L, Qin S. Functional characterization of the chlorzoxazone 6-hydroxylation activity of human cytochrome P450 2E1 allelic variants in Han Chinese. PeerJ 2020; 8:e9628. [PMID: 32821545 PMCID: PMC7397980 DOI: 10.7717/peerj.9628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/08/2020] [Indexed: 11/20/2022] Open
Abstract
BACKGROUNDS Cytochrome P450 (P450) 2E1 is one of the primary enzymes responsible for the metabolism of xenobiotics, such as drugs and environmental carcinogens. The genetic polymorphisms of the CYP2E1 gene in promoter and coding regions have been identified previously in the Han Chinese population from four different geographic areas of Mainland China. METHODS To investigate whether genetic variants identified in the CYP2E1 coding region affect enzyme function, the enzymes of four single nucleotide polymorphism (SNP) variants in the coding region (novel c.1009C>T, causing p.Arg337X, where X represents the translational stop codon; c.227G>A, causing p.Arg76His; c.517G>A, yielding p.Gly173Ser; and c.1263C>T, presenting the highest allele frequency), two novel alleles (c.[227G>A;1263C>T] and c.[517G>A;1263C>T]), and the wild-type CYP2E1 were heterologously expressed in COS-7 cells and functionally characterized in terms of expression level and chlorzoxazone 6-hydroxylation activity. The impact of the CYP2E1 variant sequence on enzyme activity was predicted with three programs: Polyphen 2, PROVEAN and SIFT. RESULTS The prematurely terminated p.Arg337X variant enzyme was undetectable by western blotting and inactive toward chlorzoxazone 6-hydroxylation. The c.1263C>T and c.[517G>A;1263C>T] variant enzymes exhibited properties similar to those of the wild-type CYP2E1. The CYP2E1 variants c.227G>A and c.[227G>A;1263C>T] displayed significantly reduced enzyme activity relative to that of the wild-type enzyme (decreased by 42.8% and 32.8%, respectively; P < 0.01). The chlorzoxazone 6-hydroxylation activity of the c.517G>A transfectant was increased by 31% compared with the wild-type CYP2E1 enzyme (P < 0.01). Positive correlations were observed between the protein content and enzyme activity for CYP2E1 (P = 0.0005, r 2 = 0.8833). The characterization of enzyme function allelic variants in vitro was consistent with the potentially deleterious effect of the amino acid changes as determined by prediction tools. CONCLUSIONS These findings indicate that the genetic polymorphisms of CYP2E1, i.e., c.1009C>T (p.Arg337X), c.227G>A (p.Arg76His), and c.517G>A (p.Gly173Ser), could influence the metabolism of CYP2E1 substrates, such as chlorzoxazone.
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Affiliation(s)
- Ting Wang
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
| | - Huihui Du
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
| | - Jingsong Ma
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
| | - Lu Shen
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
| | - Muyun Wei
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
| | - Xianglong Zhao
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
| | - Luan Chen
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
| | - Mo Li
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
| | - Guorong Li
- School of Life Sciences, Shandong Normal University, Shandong, China
| | - Qinghe Xing
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Lin He
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
- Baoan Maternal and Child Health Hospital, Jinan University, Guangdong, China
| | - Shengying Qin
- Bio-X Institutes, Shanghai Jiaotong University, Shanghai, China
- Collaborative Innovation Center, Jining Medical University, Shandong, China
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Kubiak-Tomaszewska G, Tomaszewski P, Pachecka J, Struga M, Olejarz W, Mielczarek-Puta M, Nowicka G. Molecular mechanisms of ethanol biotransformation: enzymes of oxidative and nonoxidative metabolic pathways in human. Xenobiotica 2020; 50:1180-1201. [PMID: 32338108 DOI: 10.1080/00498254.2020.1761571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ethanol, as a small-molecule organic compound exhibiting both hydrophilic and lipophilic properties, quickly pass through the biological barriers. Over 95% of absorbed ethanol undergoes biotransformation, the remaining amount is excreted unchanged, mainly with urine and exhaled air.The main route of ethyl alcohol metabolism is its oxidation to acetaldehyde, which is converted into acetic acid with the participation of cytosolic NAD+ - dependent alcohol (ADH) and aldehyde (ALDH) dehydrogenases. Oxidative biotransformation pathways of ethanol also include reactions catalyzed by the microsomal ethanol oxidizing system (MEOS), peroxisomal catalase and aldehyde (AOX) and xanthine (XOR) oxidases. The resulting acetic acid can be activated to acetyl-CoA by the acetyl-CoA synthetase (ACS).It is also possible, to a much smaller extent, non-oxidative routes of ethanol biotransformation including its esterification with fatty acids by ethyl fatty acid synthase (FAEES), re-esterification of phospholipids, especially phosphatidylcholines, with phospholipase D (PLD), coupling with sulfuric acid by alcohol sulfotransferase (SULT) and with glucuronic acid using UDP-glucuronyl transferase (UGT, syn. UDPGT).The intestinal microbiome plays a significant role in the ethanol biotransformation and in the initiation and progression of liver diseases stimulated by ethanol and its metabolite - acetaldehyde, or by lipopolysaccharide and ROS.
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Affiliation(s)
- Grażyna Kubiak-Tomaszewska
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | - Piotr Tomaszewski
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | - Jan Pachecka
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | - Marta Struga
- Department of Biochemistry, Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Wioletta Olejarz
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | | | - Grażyna Nowicka
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
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Guengerich FP. Cytochrome P450 2E1 and its roles in disease. Chem Biol Interact 2020; 322:109056. [PMID: 32198084 PMCID: PMC7217708 DOI: 10.1016/j.cbi.2020.109056] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 12/12/2019] [Accepted: 03/10/2020] [Indexed: 12/27/2022]
Abstract
Cytochrome P450 (P450) 2E1 is the major P450 enzyme involved in ethanol metabolism. That role is shared with two other enzymes that oxidize ethanol, alcohol dehydrogenase and catalase. P450 2E1 is also involved in the bioactivation of a number of low molecular weight cancer suspects, as validated in vivo in mouse models where cancers could be attenuated by deletion of Cyp2e1. P450 2E1 does not have a role in global production of reactive oxygen species but localized roles are possible, e.g. in mitochondria. The structures, conformations, and catalytic mechanisms of P450 2E1 have some unusual features among P450s. The concentration of hepatic P450 varies ≥10-fold among humans, possibly in part due to single nucleotide variants. The level of P450 2E1 may have relevance in the rates of oxidation of drugs, particularly acetaminophen and anesthetics.
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Affiliation(s)
- F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, 638 Robinson Research Building, 2200 Pierce Avenue, Nashville, TN, 37232-0146, USA.
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Abstract
Esophageal cancer (EC) is an extremely aggressive cancer with one of the highest mortality rates. The cancer is generally only diagnosed at the later stages and has a poor 5-year survival rate due to the limited treatment options. China and South Africa are two countries with a very high prevalence rate of EC. EC rates in South Africa have been on the increase, and esophageal squamous cell carcinoma is the predominant subtype and a primary cause of cancer-related deaths in the black and male mixed ancestry populations in South Africa. The incidence of EC is highest in the Eastern Cape Province, especially in the rural areas such as the Transkei, where the consumption of foods contaminated with Fusarium verticillioides is thought to play a major contributing role to the incidence of EC. China is responsible for almost half of all new cases of EC globally. In China, the prevalence of EC varies greatly. However, the two main areas of high prevalence are the southern Taihang Mountain area (Linxian, Henan Province) and the north Jiangsu area. In both countries, environmental toxins play a major role in increasing the chance that an individual will develop EC. These associative factors include tobacco use, alcohol consumption, nutritional deficiencies and exposure to environmental toxins. However, genetic polymorphisms also play a role in predisposing individuals to EC. These include single-nucleotide polymorphisms that can be found in both protein-coding genes and in non-coding sequences such as miRNAs. The aim of this review is to summarize the contribution of genetic polymorphisms to EC in South Africa and to compare and contrast this to the genetic polymorphisms observed in EC in the most comprehensively studied population group, the Chinese.
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Affiliation(s)
- Mohammed Alaouna
- Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Rodney Hull
- Research, Innovation & Engagements Portfolio, Mangosuthu University of Technology, Durban, South Africa,
| | - Clement Penny
- Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Zodwa Dlamini
- Research, Innovation & Engagements Portfolio, Mangosuthu University of Technology, Durban, South Africa,
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Ma J, Li Y, Li W, Li X. Hepatotoxicity of paraquat on common carp (Cyprinus carpio L.). THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 616-617:889-898. [PMID: 29107372 DOI: 10.1016/j.scitotenv.2017.10.231] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/22/2017] [Accepted: 10/22/2017] [Indexed: 06/07/2023]
Abstract
Paraquat (PQ) is a nonselective herbicide that is used worldwide and has been demonstrated to be a high risk to aquatic organisms. However, relatively little is known about the mechanisms on detoxification and hepatotoxicity of PQ in fish. In the present study, a sub-acute toxicity test of PQ exposure on common carp at 1.596 and 3.192mgL-1 for 7d was conducted under laboratory conditions. The results showed that the transcriptional levels of cytochrome P450s (CYPs), such as CYP1A, CYP2K, and CYP3A138, GSTα and GSTpi, and export pump gene MDR1, as well as the erythromycin-N-demethylase (ERND) activity were generally up-regulated by PQ exposure for 7d, indicating that these genes or enzymes are potentially involved in the detoxification of PQ in the fish liver. Further research showed that PQ exposure significantly increased the levels of HSP70, HSP90, NOS, and MDA; promoted expression of pro-inflammatory cytokines, including IL-6 and IL-8; altered the levels of anti-inflammatory cytokines IL-10 and TGF-β, and generally reduced the levels of T-AOC, SOD, CAT, and GSH. In addition, we also found that caspase-3, caspase-8, and caspase-9 were significantly activated in the fish liver following PQ exposure. In brief, the present study showed that PQ exposure induced fish liver injury by destabilizing the metabolism of fish, inhibiting antioxidant enzyme activity, elevating lipid peroxidation, and promoting an immune inflammatory response and apoptosis. The present study further enriches and perfects the mechanism theory of PQ hepatotoxicity to fish, which may be valuable for the risk assessment of PQ and human health protection.
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Affiliation(s)
- Junguo Ma
- College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China
| | - Yuanyuan Li
- College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China
| | - Weiguo Li
- College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xiaoyu Li
- College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China.
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Abstract
BACKGROUND Kawasaki disease (KD) is an acute febrile systemic vasculitis that disturbs coronary arteries. Patients' risks of adverse cardiovascular events and subclinical atherosclerosis have been found to significantly increase with polymorphisms of the human cytochrome P450. This current study aims to research the possible relationship between cytochrome P450, family 2, subfamily E and polypeptide 1 (CYP2E1) polymorphisms with KD. METHODS We selected 6 tag single-nucleotide polymorphisms (SNPs) of the CYP2E1 gene for TaqMan allelic discrimination assay in 340 KD patients and performed analysis on the clinical phenotypes and coronary artery lesions (CALs). CAL associations of tag SNPs were adjusted for age and gender in the logistic regression. RESULTS The KD patients with a CC genotype of rs915906 demonstrated a greater proportion of CAL formation (P = 0.009). Furthermore, the GG genotype frequencies of rs2070676 showed a significantly greater risk for CAL formation in KD patients (P = 0.007). However, the SNPs of the CYP2E1 gene did not influence CAL formation in the participating KD patients either with or without high-dose acetylsalicylic acid. Using the expression quantitative trait locus analyses, we found that the SNPs associated with CAL formation in KD also affected CYP2E1 expression in certain cell types. CONCLUSION This study is the first to find that the risk of CAL formation is related to CYP2E1 gene polymorphisms in KD patients.
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Wang L, Ren G, Li J, Zhu L, Niu F, Yan M, Li J, Yuan D, Jin T. Genetic polymorphism analysis of cytochrome P4502E1 (CYP2E1) in a Chinese Tibetan population. Medicine (Baltimore) 2017; 96:e8855. [PMID: 29381998 PMCID: PMC5708997 DOI: 10.1097/md.0000000000008855] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Cytochrome P4502E1 (CYP2E1) gene genetic polymorphisms vary markedly in frequency among different ethnic and racial groups.We studied the genotype distributions and allele frequencies of 3 CYP2E1 polymorphisms: CYP2E11A, CYP2E17A, and CYP2E17C by polymerase chain reaction technique in a sample of 100 healthy subjects representing Tibetan population.The frequencies of CYP2E11A, 7A, and 7C alleles were 0.705, 0.125, and 0.170, respectively. Compared with other populations, we found that the allele frequencies of the variants -352A>G (rs2070672) and -333A>T (rs2070673) in this Tibetan population have significant differences compared with European-American, African-American, Japanese, Korean, and other different geographic areas in Chinese Han population. Furthermore, the results of protein prediction revealed that the variant 6397G>A (rs61710826) could influence the protein structure and function.These findings in this study would be valuable for pharmacogenetics for drug therapy and drug discovery. However, further studies in larger samples are warranted to confirm our results.
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Affiliation(s)
- Li Wang
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Guoxia Ren
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of School of Medicine of Xi’an Jiaotong University, Xi’an
- Department of Intergrated Traditional Chinese and Western Medicine, Xi’an Chest Hospital, Xi’an
| | - Jingjie Li
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Sciences, Northwest University, Xi’an, Shaanxi, China
| | - Linhao Zhu
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Fanglin Niu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Sciences, Northwest University, Xi’an, Shaanxi, China
| | - Mengdan Yan
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Sciences, Northwest University, Xi’an, Shaanxi, China
| | - Jing Li
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Sciences, Northwest University, Xi’an, Shaanxi, China
| | - Dongya Yuan
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Tianbo Jin
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Sciences, Northwest University, Xi’an, Shaanxi, China
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Ma J, Feng Y, Jiang S, Li X. Altered cellular metabolism of HepG2 cells caused by microcystin-LR. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 225:610-619. [PMID: 28336091 DOI: 10.1016/j.envpol.2017.03.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/20/2017] [Accepted: 03/14/2017] [Indexed: 06/06/2023]
Abstract
This study aimed to evaluate the possible effects of microcystin-LR (MC-LR) exposure on the metabolism and drug resistance of human hepatocellular carcinoma (HepG2) cells. For this purpose, we first conducted an experiment to make sure that MC-LR could penetrate the HepG2 cell membrane effectively. The transcriptional levels of phase I (such as CYP2E1, CYP3A4, and CYP26B1) and phase II (such as EPHX1, SULTs, and GSTM) enzymes and export pump genes (such as MRP1 and MDR1) were altered by MC-LR-exposure for 24 h, indicating that MC-LR treatment may destabilize the metabolism of HepG2 cells. Further research showed that the CYP inducers omeprazole, ethanol, and rifampicin inhibited cell viability, in particular, ethanol, a CYP2E1 inducer, induced ROS generation, lipid peroxidation, and apoptosis in HepG2 cells treated with MC-LR. The CYP2E1 inhibitor chlormethiazole inhibited ROS generation, mitochondrial membrane potential loss, caspase-3 activity, and cytotoxicity caused by MC-LR. Meanwhile, the results also showed that co-incubation with the ROS scavenger l-ascorbic acid and MC-LR decreased ROS levels and effectively prevented apoptosis. These findings provide an interesting mechanistic explanation of cellular metabolism associated with MC-LR, i.e., MC-LR-exposure exerted toxicity on HepG2 cells and induced apoptosis of HepG2 cells via promoting CYP2E1 expression and inducing excessive ROS in HepG2 cells.
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Affiliation(s)
- Junguo Ma
- College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China
| | - Yiyi Feng
- College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China
| | - Siyu Jiang
- College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xiaoyu Li
- College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China.
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Hepatotoxicity in Rats Induced by Aqueous Extract of Polygoni Multiflori Radix, Root of Polygonum multiflorum Related to the Activity Inhibition of CYP1A2 or CYP2E1. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017. [PMID: 28626488 PMCID: PMC5463189 DOI: 10.1155/2017/9456785] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The objective of this study is to investigate the relationship between the hepatotoxicity induced by Polygoni Multiflori Radix (PMR, root of Polygonum multiflorum Thunb., He Shou Wu) and the activity of CYP1A2 or CYP2E1 in the rat liver. Levels of rat serum transaminases ALT and AST were not altered but the activity of CYP1A2 or CYP2E1 in the rat liver was significantly inhibited after oral administration of aqueous extract of PMR under the experimental dosage. However, levels of ALT and AST were significantly increased and the activity of CYP1A2 or CYP2E1 was significantly decreased after injection of specific inhibitor for CYP1A2 or CYP2E1 combined with oral administration of aqueous extract of PMR, especially under the repeated treatment over interval times. Liver histopathological observation showed that a moderate liver injury occurred in rats receiving PMR treatment with the activity of CYP1A2 or CYP2E1 inhibited, but there was no significant liver damage in rats receiving PMR treatment or CYP inhibitor alone. These suggested that low level activity of CYP1A2 or CYP2E1 from genetic polymorphism among people might be one of the important reasons for the hepatotoxicity induced by PMR in clinical practice.
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13
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Ben Chaaben A, Abaza H, Douik H, Chaouch L, Ayari F, Ouni N, Mamoghli T, Ben Guezella D, Mejri R, Harzallah L, Guemira F. [Genetic polymorphism of cytochrome P450 2E1 and the risk of nasopharyngeal carcinoma]. Bull Cancer 2015; 102:967-72. [PMID: 26582733 DOI: 10.1016/j.bulcan.2015.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 09/17/2015] [Indexed: 01/15/2023]
Abstract
Cytochrome P450 2E1 (CYP2E1) is a detoxifying enzyme that belongs to the phase I metabolism of xenobiotics. This enzyme is encoded by a highly polymorphic gene whose common polymorphism corresponds to the substitution of cytosine (C) and thymine (T) at position -1019 (rs2031920). This polymorphism has been identified in several cancers including nasopharyngeal cancer (NPC). The study involved 124 patients with nasopharyngeal carcinoma, compared with 166 healthy controls. The presence or absence of the polymorphism is determined by PCR-RFLP. The frequency comparison between the two groups is determined by the χ(2) test. The analysis of our results showed a significant difference between the two groups regarding the mutant genotype (C2/C2) (5% vs. 0.5%, P=0.04) and has a risk factor for NPC in Tunisia (OR=8.39; CI 95% [0.99-388.1]). Also, the C2 allele was significantly associated with the group of patients than the control group (6% vs. 2%, P=0.016) and increased three times the risk of NPC in Tunisia (OR=2.99, CI 95% [1.12-8.79]). Our results confirm the results reported in other populations and emphasize the importance of the involvement of this gene in the development of detoxification of the NPC, which seems more and more strongly associated with environmental factors.
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Affiliation(s)
- Arij Ben Chaaben
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie.
| | - Hajer Abaza
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie
| | - Hayet Douik
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie
| | - Leila Chaouch
- Institut Pasteur de Tunis, laboratoire d'hématologie moléculaire et cellulaire, Tunis, Tunisie
| | - Fayza Ayari
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie
| | - Nesrine Ouni
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie
| | - Tasnim Mamoghli
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie
| | | | - Rachida Mejri
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie
| | - Latifa Harzallah
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie
| | - Fethi Guemira
- Institut Salah Azaiz, laboratoire de biologie Clinique, Tunis, Tunisie
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Abstract
Esophageal cancer (EC) is one of the most common malignancies in low- and medium-income countries and represents a disease of public health importance because of its poor prognosis and high mortality rate in these regions. The striking variation in the prevalence of EC among different ethnic groups suggests a significant contribution of population-specific environmental and dietary factors to susceptibility to the disease. Although individuals within a demarcated geographical area are exposed to the same environment and share similar dietary habits, not all of them will develop the disease; thus genetic susceptibility to environmental risk factors may play a key role in the development of EC. A wide range of xenobiotic-metabolizing enzymes are responsible for the metabolism of carcinogens introduced via the diet or inhaled from the environment. Such dietary or environmental carcinogens can bind to DNA, resulting in mutations that may lead to carcinogenesis. Genes involved in the biosynthesis of these enzymes are all subject to genetic polymorphisms that can lead to altered expression or activity of the encoded proteins. Genetic polymorphisms may, therefore, act as molecular biomarkers that can provide important predictive information about carcinogenesis. The aim of this review is to discuss our current knowledge on the genetic risk factors associated with the development of EC in different populations; it addresses mainly the topics of genetic polymorphisms, gene-environment interactions, and carcinogenesis. We have reviewed the published data on genetic polymorphisms of enzymes involved in the metabolism of xenobiotics and discuss some of the potential gene-environment interactions underlying esophageal carcinogenesis. The main enzymes discussed in this review are the glutathione S-transferases (GSTs), N-acetyltransferases (NATs), cytochrome P450s (CYPs), sulfotransferases (SULTs), UDP-glucuronosyltransferases (UGTs), and epoxide hydrolases (EHs), all of which have key roles in the detoxification of environmental and dietary carcinogens. Finally, we discuss recent advances in the study of genetic polymorphisms associated with EC risk, specifically with regard to genome-wide association studies, and examine possible challenges of case-control studies that need to be addressed to better understand the interaction between genetic and environmental factors in esophageal carcinogenesis.
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Affiliation(s)
- Marco Matejcic
- a International Centre for Genetic Engineering and Biotechnology, Cape Town Component , Observatory , Cape Town , South Africa , and
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15
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Glesse N, Rohr P, Monticielo OA, Rech TF, Brenol JCT, Xavier RM, Kvitko K, Chies JAB. Genetic polymorphisms of glutathione S-transferases and cytochrome P450 enzymes as susceptibility factors to systemic lupus erythematosus in southern Brazilian patients. Mol Biol Rep 2014; 41:6167-79. [DOI: 10.1007/s11033-014-3496-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 06/17/2014] [Indexed: 01/05/2023]
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Lee JK, Chung HJ, Fischer L, Fischer J, Gonzalez FJ, Jeong H. Human placental lactogen induces CYP2E1 expression via PI 3-kinase pathway in female human hepatocytes. Drug Metab Dispos 2014; 42:492-9. [PMID: 24408518 PMCID: PMC3965907 DOI: 10.1124/dmd.113.055384] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 01/08/2014] [Indexed: 12/29/2022] Open
Abstract
The state of pregnancy is known to alter hepatic drug metabolism. Hormones that rise during pregnancy are potentially responsible for the changes. Here we report the effects of prolactin (PRL), placental lactogen (PL), and growth hormone variant (GH-v) on expression of major hepatic cytochromes P450 expression and a potential molecular mechanism underlying CYP2E1 induction by PL. In female human hepatocytes, PRL and GH-v showed either no effect or small and variable effects on mRNA expression of CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1, 3A4, and 3A5. On the other hand, PL increased expression level of CYP2E1 mRNA with corresponding increases in CYP2E1 protein and activity levels. Results from hepatocytes and HepaRG cells indicate that PL does not affect the expression or activity of HNF1α, the known transcriptional activator of basal CYP2E1 expression. Furthermore, transient transfection studies and Western blot results showed that STAT signaling, the previously known mediator of PL actions in certain tissues, does not play a role in CYP2E1 induction by PL. A chemical inhibitor of PI3-kinase signaling significantly repressed the CYP2E1 induction by PL in human hepatocytes, suggesting involvement of PI3-kinase pathway in CYP2E1 regulation by PL. CYP2E1-humanized mice did not exhibit enhanced CYP2E1 expression during pregnancy, potentially because of interspecies differences in PL physiology. Taken together, these results indicate that PL induces CYP2E1 expression via PI3-kinase pathway in human hepatocytes.
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Affiliation(s)
- Jin Kyung Lee
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois (J.K.L., H.J.C., L.F., J.F., H.J.); College of Pharmacy, Gyeongsang National University, Jinju, South Korea (H.J.C.); Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois (H.J.)
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17
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Chong ETJ, Lee CC, Chua KH, Chuah JA, Lee PC. RsaI but not DraI polymorphism in CYP2E1 gene increases the risk of gastrointestinal cancer in Malaysians: a case-control study. BMJ Open 2014; 4:e004109. [PMID: 24394801 PMCID: PMC3902529 DOI: 10.1136/bmjopen-2013-004109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVES Our study aimed to investigate the association of CYP2E1 C-1019T RsaI and T7678A DraI polymorphisms and factors such as age, gender and ethnicity to the risk of gastrointestinal cancer (GIC) in Malaysians. DESIGN Case-control study. SETTING Malaysia. PARTICIPANTS 520 consented healthy blood donors with no previous GIC record and 175 patients with GIC. MEASUREMENTS C-1019T RsaI and T7678A DraI genotyping of CYP2E1 gene; direct sequencing. RESULTS This study reveals that the variant c2 allele and carrier with at least one c2 allele of C-1019T single nucleotide polymorphism (SNP) significantly increased the risk of GIC but no significant association was found between T7678A SNP and combined analysis of C-1019T and T7678A SNPs to risk of GIC. The Malaysian Chinese had greater risk of GIC compared with the Malays, Indians and KadazanDusun. An increased risk of GIC was observed in individuals aged >40 years and women had a 2.22-fold and 1.58-fold increased risk of stomach and colorectal cancers, respectively, when compared with men. LIMITATIONS The future research should be conducted with a larger sample population and including the gene-gene and gene-environmental interactions. CONCLUSIONS Our study suggests that the rare c2 allele and carrier with at least one c2 allele of CYP2E1 RsaI polymorphism significantly elevated the risk of GIC and may be used as a genetic biomarker for early screening of GIC in Malaysians. The risk age-group has been shifted to a younger age at 40s and women showed a significant greater risk of stomach and colorectal cancers than men.
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Affiliation(s)
- Eric Tzyy Jiann Chong
- School of Science and Technology, Universiti Malaysia Sabah, Jalan UMS, Kota Kinabalu, Sabah, Malaysia
| | - Chong Cin Lee
- School of Science and Technology, Universiti Malaysia Sabah, Jalan UMS, Kota Kinabalu, Sabah, Malaysia
| | - Kek Heng Chua
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jitt Aun Chuah
- Surgery Department, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
| | - Ping-Chin Lee
- School of Science and Technology, Universiti Malaysia Sabah, Jalan UMS, Kota Kinabalu, Sabah, Malaysia
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Abstract
Concomitant use of alcohol and medications may lead to potentially serious medical conditions. Increasing prescription medication abuse in today's society necessitates a deeper understanding of the mechanisms involved in alcohol-medication interactions in order to help prevent adverse events. Interactions of medications with alcohol result in altered bioavailability of the medication or alcohol (pharmacokinetic interactions) or modification of the effects at receptor or ion channel sites to alter behavioral or physical outcome (pharmacodynamic interactions). The nature of pharmacokinetic or pharmacodynamic interactions involved in alcohol-medication interactions may differ between acute and chronic alcohol use and be influenced by race, gender, or environmental or genetic factors. This review focuses on the mechanisms underlying pharmacokinetic and pharmacodynamic interactions between alcohol and medications and provides examples for such interactions from replicated research studies. In conclusion, further translational research is needed to address several gaps in our current knowledge of alcohol-medication interactions, including those under various pathologic conditions.
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Affiliation(s)
- Bankole A Johnson
- Department of Psychiatry and Brain Science Research Consortium at the University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Chamindi Seneviratne
- Department of Psychiatry, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
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19
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Shahriary GM, Galehdari H, Jalali A, Zanganeh F, Alavi SMR, Aghanoori MR. CYP2E1*5B, CYP2E1*6, CYP2E1*7B, CYP2E1*2, and CYP2E1*3 Allele Frequencies in Iranian Populations. Asian Pac J Cancer Prev 2012; 13:6505-10. [DOI: 10.7314/apjcp.2012.13.12.6505] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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20
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Abstract
Over the last three decades, direct hepatotoxic effects of ethanol were established, some of which were linked to redox changes produced by NADH generated via the alcohol dehydrogenase (ADH) pathway and shown to affect the metabolism of lipids, carbohydrates, proteins, and purines. It was also determined that ethanol can be oxidized by a microsomal ethanol oxidizing system (MEOS) involving a specific cytochrome P-450; this newly discovered ethanol-inducible cytochrome P-450 (P-450 IIEi) contributes to ethanol metabolism, tolerance, energy wastage (with associated weight loss), and the selective hepatic perivenular toxicity of various xenobiotics. Their activation by P-450IIEi now provides an understanding of the increased susceptibility of the heavy drinker to the toxicity of industrial solvents, anaesthetic agents, commonly prescribed drugs, over-the-counter analgesics, and chemical carcinogens. P-450 induction also explains depletion (and toxicity) of nutritional factors such as vitamin A. As a consequence, treatment with vitamin A and other nutritional factors is beneficial, but must take into account a narrowed therapeutic window in alcoholics who have increased needs for nutrients and also display an enhanced susceptibility to some of their adverse effects. Acetaldehyde (the metabolite produced from ethanol by either ADH or MEOS) impairs hepatic oxygen utilization and forms protein adducts, resulting in antibody production, enzyme inactivation, and decreased DNA repair. It also stimulates collagen production by the vitamin A storing cells (lipocytes) and myofibroblasts, and causes glutathione depletion. Supplementation with S-adenosyl-L-methionine partly corrects the depletion and associated mitochondrial injury, whereas administration of polyunsaturated lecithin opposes the fibrosis. Thus, at the cellular level, the classic dichotomy between the nutritional and toxic effects of ethanol has now been bridged. The understanding of how the ensuing injury eventually results in irreversible scarring or cirrhosis may provide us with improved modalities for treatment and prevention.
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Affiliation(s)
- C S Lieber
- Alcohol Research & Treatment Center, Bronx VA Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA
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21
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Catanzaro I, Naselli F, Saverini M, Giacalone A, Montalto G, Caradonna F. Cytochrome P450 2E1 variable number tandem repeat polymorphisms and health risks: a genotype-phenotype study in cancers associated with drinking and/or smoking. Mol Med Rep 2012; 6:416-20. [PMID: 22614694 DOI: 10.3892/mmr.2012.914] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 04/25/2012] [Indexed: 11/06/2022] Open
Abstract
Cytochrome P450 2E1 (CYP2E1) is one of the main enzymes involved in the oxidation of ethanol and in the transformation of a number of potentially dangerous compounds. It has various polymorphic sites, one of which is a variable number tandem repeat (VNTR) polymorphism previously described in the 5'-flanking region. The aim of this study was to investigate the genotype-phenotype association between CYP2E1 VNTR polymorphisms and risky health habits in healthy subjects and to analyze the associations between these polymorphisms with drinking- and/or smoking-related cancers. We analyzed 166 healthy subjects by genotyping for the CYP2E1 VNTR polymorphism associated with drinking and/or smoking habits by the more sensitive restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) method, using the NlaIV restriction enzyme. Sixty cases of pancreatic adenocarcinoma (PA) and 66 with hepatocellular carcinoma (HCC), were also genotyped. Statistical analysis was carried out to investigate the genotype-phenotype associations and to compare certain genotypes and cancer. We found 7 genotypes both in the healthy subjects and patients. The A1/A1 genotype was observed to be mainly associated with non-drinkers and -smokers (87.5 and 75.0%, respectively); moreover it was never found in the PA or HCC patients. Conversely, a weak association between A2/A3 with smokers (45.8%) and A4/A4 with drinkers (53.9%) was detected. In addition, the A4/A4 genotype was found to be significantly associated to PA [odds ratio (OR)=3.25; 95% confidence interval (CI) 1.21-7.50]. Our data demonstrate that certain CYP2E1 VNTR genotypes are associated with drinking and/or smoking habits; consequently, they may contribute either to the decreased or increased risk of developing drinking- and/or smoking-related cancers. In particular, we hypothesize that the A1/A1 VNTR genotype may have a protective role against drinking- and/or smoking-related cancers, and that A4/A4 may be a high-risk genotype during the early stages of cancer.
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Affiliation(s)
- Irene Catanzaro
- Department of Molecular and Biomolecular Sciences and Technologies (STEMBIO), Section of Cellular Biology, University of Palermo, I-90128 Palermo, Italy
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22
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Feng J, Pan X, Yu J, Chen Z, Xu H, El-Rifai W, Zhang G, Xu Z. Functional PstI/RsaI polymorphism in CYP2E1 is associated with the development, progression and poor outcome of gastric cancer. PLoS One 2012; 7:e44478. [PMID: 22957075 PMCID: PMC3434136 DOI: 10.1371/journal.pone.0044478] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 08/07/2012] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Cytochrome P450 2E1 (CYP2E1), an ethanol-inducible enzyme, has been shown to metabolically activate various carcinogens, which is critical for the development and progression of cancers. It has demonstrated that CYP2E1 polymorphisms alter the transcriptional activity of the gene. However, studies on the association between CYP2E1 polymorphisms (PstI/RsaI or DraI) and gastric cancer have reported conflicting results. Thus, the aim of the present study was to investigate whether CYP2E1 polymorphisms is associated with the development and progression of gastric cancer and its prognosis in Chinese patients. METHODS A case-control study was conducted in which CYP2E1 PstI/RsaI and DraI polymorphisms were analyzed in 510 Chinese patients with gastric cancer and 510 age- and sex- matched healthy controls by PCR-RFLP. Odds ratios were estimated by multivariate logistic regression, and the lifetime was calculated by Kaplan-Meier survival curves. In addition, a meta-analysis was also conducted to verify the findings. RESULTS For CYP2E1 PstI/RsaI polymorphism, C2C2 homozygotes (OR = 2.15; CI: 1.18-3.94) and C2 carriers (OR = 1.48; CI: 1.13-1.96) were associated with an increased risk of gastric cancer when compared with C1C1 homozygotes. Both C1C2 and C2C2 genotypes were associated with advanced stage, but not the grade of gastric cancer. Moreover, C2C2 genotype was identified as an independent marker of poor overall survival for gastric cancer. However, there was not any significant association between CYP2E1 DraI polymorphism and the risk of gastric cancer. In the meta-analysis, pooled data from 13 studies confirmed that the CYP2E1 PstI/RsaI polymorphism was associated with a significantly increased risk of gastric cancer. CONCLUSION CYP2E1 PstI/RsaI polymorphism is associated with increased risk of development, progression and poor prognosis of gastric cancer in Chinese patients. Pooled data from 13 studies, mainly in Asian countries, are in agreement with our findings.
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Affiliation(s)
- Jin Feng
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xiaolin Pan
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Junbo Yu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zheng Chen
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hao Xu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Wael El-Rifai
- Department of Surgery, Cancer Biology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Guoxin Zhang
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
- * E-mail: (ZX); (GZ)
| | - Zekuan Xu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
- * E-mail: (ZX); (GZ)
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Sevior DK, Pelkonen O, Ahokas JT. Hepatocytes: the powerhouse of biotransformation. Int J Biochem Cell Biol 2011; 44:257-61. [PMID: 22123318 DOI: 10.1016/j.biocel.2011.11.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 10/12/2011] [Accepted: 11/14/2011] [Indexed: 01/10/2023]
Abstract
Liver is the most important organ involved in biotransformation of xenobiotics. Within the main organisational unit, the hepatocyte, is an assembly of enzymes commonly classified as phase I and phase II enzymes. The phase I enzymes principally cytochrome P450 catalyse both oxidative and reductive reactions of a bewildering number of xenobiotics. Many of the products of phase I enzymes become substrates for the phase II enzymes, which catalyse conjugation reactions making use of endogenous cofactors. As xenobiotic metabolising enzymes are responsible for the toxicity of many chemicals and drugs, testing the role of the biotransformation enzymes and the transporters within the hepatocyte is critical. New methodologies may be able to provide information to allow for better in vitro to in vivo extrapolation of data.
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24
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Singh S, Sherkhane PD, Kale SP, Eapen S. Expression of a human cytochrome P4502E1 in Nicotiana tabacum enhances tolerance and remediation of γ-hexachlorocyclohexane. N Biotechnol 2011; 28:423-9. [PMID: 21458603 DOI: 10.1016/j.nbt.2011.03.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 03/15/2011] [Accepted: 03/24/2011] [Indexed: 10/18/2022]
Abstract
Lindane (γ-hexachlorocyclohexane), a persistent organo-chlorine insecticide widely used in developing countries, has a negative effect as a polluting agent of soil and surface waters. Plants can be used for remediation of organic pollutants and their efficiency can be enhanced by introduction of heterologous genes. Mammalian cytochrome P4502E1 (CYP2E1), an important monooxygenase is involved in the degradation of a wide range of xenobiotics including environmental pollutants/herbicides and pesticides. Here, we report the development of transgenic tobacco plants expressing human CYP2E1 and the efficacy of plants for remediation of lindane. Transgenic tobacco plants with CYP2E1 showed enhanced tolerance to lindane when grown in hydroponic medium and soil compared to control plants. Remediation of (14)C-labeled lindane from hydroponic medium was higher in transgenic plants compared to that of control plants, with the best performing line showing 25% higher removal of lindane from solution than control plants. Similar results were seen in plants grown in soil spiked with lindane. The present study has shown that transgenic plants expressing CYP2E1 gene have potential use for remediation of lindane from contaminated solutions and soil.
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Affiliation(s)
- Sudhir Singh
- Nuclear Agriculture & Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
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25
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Pohl HR, Scinicariello F. The impact of CYP2E1 genetic variability on risk assessment of VOC mixtures. Regul Toxicol Pharmacol 2011; 59:364-74. [PMID: 21295098 DOI: 10.1016/j.yrtph.2011.01.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 01/26/2011] [Accepted: 01/28/2011] [Indexed: 01/14/2023]
Abstract
Humans are simultaneously exposed to multiple chemicals in the environment. Many of the chemicals use the same enzymes in their metabolic pathways. Competitive inhibition may occur as one of the possible interactions between the xenobiotics in human body. For example, many volatile organic compounds (VOCs) are metabolized using P450 enzymes, specifically CYP2E1. Inheritable gene alterations may result in changes of function of the enzymes in different human subpopulations. Variations in quantity and/or quality of particular isoenzymes may cause differences in the metabolism of VOCs. These variations may cause higher sensitivity in certain populations. Using examples of three different mixtures, this review paper outlines the variances in CYP2E1 isoenzymes, effect of exposure to such mixtures on sensitive populations, and approaches to mixtures risk assessment.
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Affiliation(s)
- Hana R Pohl
- Agency for Toxic Substances and Disease Registry, US Department of Health and Human Services, Atlanta, GA 30333, USA.
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26
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Wang Y, Guan S, Acharya P, Koop DR, Liu Y, Liao M, Burlingame AL, Correia MA. Ubiquitin-dependent proteasomal degradation of human liver cytochrome P450 2E1: identification of sites targeted for phosphorylation and ubiquitination. J Biol Chem 2011; 286:9443-56. [PMID: 21209460 DOI: 10.1074/jbc.m110.176685] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human liver CYP2E1 is a monotopic, endoplasmic reticulum-anchored cytochrome P450 responsible for the biotransformation of clinically relevant drugs, low molecular weight xenobiotics, carcinogens, and endogenous ketones. CYP2E1 substrate complexation converts it into a stable slow-turnover species degraded largely via autophagic lysosomal degradation. Substrate decomplexation/withdrawal results in a fast turnover CYP2E1 species, putatively generated through its futile oxidative cycling, that incurs endoplasmic reticulum-associated ubiquitin-dependent proteasomal degradation (UPD). CYP2E1 thus exhibits biphasic turnover in the mammalian liver. We now show upon heterologous expression of human CYP2E1 in Saccharomyces cerevisiae that its autophagic lysosomal degradation and UPD pathways are evolutionarily conserved, even though its potential for futile catalytic cycling is low due to its sluggish catalytic activity in yeast. This suggested that other factors (i.e. post-translational modifications or "degrons") contribute to its UPD. Indeed, in cultured human hepatocytes, CYP2E1 is detectably ubiquitinated, and this is enhanced on its mechanism-based inactivation. Studies in Ubc7p and Ubc5p genetically deficient yeast strains versus corresponding isogenic wild types identified these ubiquitin-conjugating E2 enzymes as relevant to CYP2E1 UPD. Consistent with this, in vitro functional reconstitution analyses revealed that mammalian UBC7/gp78 and UbcH5a/CHIP E2-E3 ubiquitin ligases were capable of ubiquitinating CYP2E1, a process enhanced by protein kinase (PK) A and/or PKC inclusion. Inhibition of PKA or PKC blocked intracellular CYP2E1 ubiquitination and turnover. Here, through mass spectrometric analyses, we identify some CYP2E1 phosphorylation/ubiquitination sites in spatially associated clusters. We propose that these CYP2E1 phosphorylation clusters may serve to engage each E2-E3 ubiquitination complex in vitro and intracellularly.
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Affiliation(s)
- YongQiang Wang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158-2517, USA
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Cytochrome 3A and 2E1 in human liver tissue: Individual variations among normal Japanese subjects. Life Sci 2010; 86:393-401. [PMID: 20102722 DOI: 10.1016/j.lfs.2010.01.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 01/07/2010] [Accepted: 01/12/2010] [Indexed: 12/28/2022]
Abstract
AIMS The metabolism of drugs, xenobiotic compounds, and other endogenous/exogenous substrates generally begins with their oxidation through cytochrome P450 (CYP). The results of recent pharmacogenetic analyses have demonstrated CYP's polymorphisms to be related to individual differences in metabolism, but only a limited number of CYP3A4 and CYP2E1 variant alleles influence enzymatic activities. Therefore, CYP gene expression profiling of both normal and pathological human livers should provide critical information for an evaluation of the biological significance of CYPs. MAIN METHODS In our present study, we first characterized the individual differences in CYP3A4 and CYP2E1 expression levels among Japanese normal or non-pathological liver tissue obtained from autopsy or surgery using immunohistochemistry and quantitative RT-PCR array of phase I metabolic enzymes with combined laser capture microscopy and qPCR analysis. KEY FINDINGS Both CYP3A4 and CYP2E1 mRNA and proteins were predominantly detected in hepatocytes surrounding central veins in normal liver, but there were marked individual differences in both CYP3A4 and CYP2E1 mRNA and proteins among the 23 Japanese subjects examined. Individual differences in CYP3A and CYP2E1 subtypes were also detected in the livers obtained from monozygotic neonatal Japanese female twins with different survival periods. CYP3A and CYP2E1-positive cells were decreased in number in non-pathological hepatocytes of diseased livers compared to those in disease-free livers from autopsy. SIGNIFICANCE The above results suggest that individual differences in CYP3A4 and CYP2E1 exist among normal human liver tissues and in non-pathological hepatocytes between diseased and normal liver, and these differences may be important in evaluating the pharmacodynamics of various substances.
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Shahabi HN, Westberg L, Melke J, Håkansson A, Belin AC, Sydow O, Olson L, Holmberg B, Nissbrandt H. Cytochrome P450 2E1 gene polymorphisms/haplotypes and Parkinson's disease in a Swedish population. J Neural Transm (Vienna) 2009; 116:567-73. [PMID: 19381774 DOI: 10.1007/s00702-009-0221-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 03/21/2009] [Indexed: 11/26/2022]
Abstract
Cytochrome P450 2E1 (CYP2E1), which inter alia is located in dopamine containing neurons in the substantia nigra, has been hypothesized to be of importance for the pathophysiology of Parkinson's disease (PD), either by its production of reactive oxygen species (ROS) or by its capability to detoxify putative neurotoxins. Numerous polymorphisms in the coding and non-coding regions of the gene for this enzyme have been reported. Different variants may account for inter-individual differences in the activity of the enzyme or production of ROS. In this study, the CYP2E1 gene was examined in a control population (n = 272) and a population with PD (n = 347), using a tag-single nucleotide polymorphism (tSNP) approach founded on HapMap Data. Six tSNPs were used in the analysis and haplotype block data were obtained. In case of significance, the SNP was further examined regarding early/late age of disease onset and presence of relatives with PD. We found an association between allele and genotype frequencies of the C/G polymorphism at intron 7 (rs2070676) of this gene and PD (P value of 0.026 and 0.027, respectively). Furthermore, analysis of the rs2070676 polymorphism in subgroups of patients with age of disease onset higher than 50 years and those not having a relative with PD also demonstrated a significant difference with controls. This was seen in both genotype (corresponding to P value = 0.039 and 0.032) and allele (P = 0.027 and 0.017 respectively) frequency. As a representative of many polymorphisms or in possible linkage disequilibrium with other functional variants, it is possible that rs2070676 could influence the regulation of the enzyme. In conclusion, our results display an association between the rs2070676 polymorphism and PD. Additional investigations are needed to elucidate the importance of this polymorphism for the activity of CYP2E1 and PD susceptibility.
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Affiliation(s)
- H Niazi Shahabi
- Department of Pharmacology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
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Kimura T, Kawasaki Y, Okumura F, Sone T, Natsuki R, Isobe M. Ethanol-induced expression of glutamate–cysteine ligase catalytic subunit gene is mediated by NF-κB. Toxicol Lett 2009; 185:110-5. [DOI: 10.1016/j.toxlet.2008.12.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 12/05/2008] [Accepted: 12/05/2008] [Indexed: 10/21/2022]
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Miller GP. Advances in the interpretation and prediction of CYP2E1 metabolism from a biochemical perspective. Expert Opin Drug Metab Toxicol 2008; 4:1053-64. [PMID: 18680440 DOI: 10.1517/17425255.4.8.1053] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Cytochrome P450 2E1 (CYP2E1) plays a central role in the metabolism and metabolic activation of a large number of small, mostly xenobiotic compounds. These qualities distinguish CYP2E1 from traditional enzymes and pose significant challenges to understanding the role and consequences of CYP2E1-mediated metabolism. OBJECTIVE This review discusses recent advances in kinetic profiling, quantitative structure-activity relationships and structural studies that have furthered the development of tools to interpret and predict CYP2E1 metabolism. METHODS Analysis of kinetic profiles by specific mechanisms produces important parameters describing specificity, stoichiometry and metabolism of molecules. Quantitative structure-activity relationships reveal a more specific basis for molecular recognition by CYP2E1. The corresponding protein structures imparting these interactions are the focus of chemical modifications, site-directed mutagenesis and homology modeling studies. RESULTS Compilation of kinetic profiling for CYP2E1 substrates established the selectivity for small substrates, whose characteristics could be generalized in parameters for hydrophobicity and steric properties as determined by quantitative structure-activity relationships. The possibility of an effector site for monocyclic compounds added an interesting variable to these modeling efforts. Various structural studies identified important residues contributing to binding and catalysis as well as the volume and location of the active site relative to the heme moiety. Pressure and carbon monoxide-binding experiments also demonstrated the inherent conformational flexibility of CYP2E1 that may contribute to rate-limiting steps during catalytic turnover. CONCLUSION Although combinations of these approaches have reinforced important observations, more work is needed to verify findings and seek broader impacts for various interpretative and predictive tools.
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Affiliation(s)
- Grover P Miller
- University of Arkansas for Medical Sciences, Department of Biochemistry and Molecular Biology, 4301 W. Markham Street, Slot 516, Little Rock, AR 72205, USA.
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31
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Zhang Y, Liu Q, Liu Q, Duan H, Cheng J, Jiang S, Huang X, Leng S, He F, Zheng Y. Association between metabolic gene polymorphisms and susceptibility to peripheral nerve damage in workers exposed ton-hexane: A preliminary study. Biomarkers 2008; 11:61-9. [PMID: 16484137 DOI: 10.1080/13547500500451176] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Chronic exposure to n-hexane may result in peripheral neuropathy. 2,5-Hexanedione (2,5-HD) has been identified as a toxic metabolite of n-hexane. The CYP2E1, CYP1A1 and GST genes are involved in the formation of 2,5-hexanedione from n-hexane as well as the elimination of 2,5-HD-formed electrophile, and these genes are highly polymorphic in the general population. A nested case-control study in an industrial cohort was conducted to evaluate the associations between polymorphisms in these metabolic genes and n-hexane-induced peripheral nerve damage. The study subjects included 22 cases, who worked in a printing factory with symptoms of peripheral nerve damage, and 163 controls, who came from the same factory of cases. DNA was extracted from blood samples and genotyping was conducted for CYP2E1 Pst, CYP2E1 Dra, CYP2E1 Ins96, CYP1A1 Msp, GSTT1 null, GSTM1 null and GSTP1 105V. Unconditional logistic regression was applied to estimate the odds ratio and 95% confidence intervals. There were no significant differences between the two groups regarding age, sex, smoking and alcohol status. A significant association between Dra polymorphism and peripheral nerve damage was found. The frequency of CYP2E1 Dra homozygous mutation in the case group (18.2%) was higher than that in the control group (3.7%, p=0.015). Individuals with homozygote genotype (CC) of CYP2E1 Dra had a significantly higher risk of peripheral nerve damage compared with those with DD genotype (adjusted OR=?.58, 95% CI=1.32-23.65) after n-hexane exposure duration, sex, age, smoking and alcohol status were adjusted. No significant association was found that CYP2E1 Pst, CYP2E1 Ins96, CYP1A1 Msp, GSTT1, GSTM1, GSTP gene polymorphisms associated with the susceptibility of peripheral nerve damage. These findings suggested that CYP2E1 gene might increase the susceptibility to n-hexane-induced peripheral damage.
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Affiliation(s)
- Y Zhang
- National Institute for Occupational Health and Poison Control, Chinese Centre for Disease Control and Prevention, Beijing, China
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Hayashi N, Tsutsumi M, Fukura M, Yano H, Tsuchishima M, Takase S. Effect of chronic dietary ethanol consumption on colonic cancer in rats induced by 1,1-dimethylhydrazine. Alcohol Clin Exp Res 2008; 31:S72-6. [PMID: 17331170 DOI: 10.1111/j.1530-0277.2006.00290.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND The pathogenetic correlation between chronic alcohol consumption and development of colon cancer is not clear. The role of alcohol abuse in the carcinogenic action of 1,1-dimethylhydrazine (DMH), which induces tumors in the colon, was evaluated. METHODS Twenty male rats were fed liquid diets containing ethanol or carbohydrates for 39 weeks. DMH (20 mg/kg body weight, once a week) was injected subcutaneously from the 5th to the 20th week. Pair feeding was stopped at 10:00 am and DMH was administered at 02:00 pm. Ethanol was not detected in the blood at the time of injection. Liquid diets were provided again at 05:00 pm until 10:00 am next day. The animals were killed at the end of the 39th week, and the colons were removed for examination for the number of aberrant crypt foci (ACF) by methylene blue staining. Tissue sections were stained for histology and cytochrome P4502E1 (CYP2E1) expression. RESULTS The number of ACF in colons obtained from ethanol-fed rats with DMH was 24 (n=5, 4.4+/-2.5/rat), which was significantly (p<0.001) more than that of the other treated rats: only 3 (n=5, 0.6+/-0.5/rat) in the pair-fed control rats with DMH, and none in the ethanol-fed or control-fed rats without DMH. Cytochrome P4502E1 staining demonstrated marked expression in the colon mucosa from ethanol-fed rats, but not in the pair-fed control rats. CONCLUSIONS The increased expression of CYP2E1 induced by chronic ethanol consumption promotes the development of DMH-induced colon cancer.
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Affiliation(s)
- Nobuhiko Hayashi
- Department of Gastroenterology, Kanazawa Medical University, Uchinada, Ishikawa, Japan
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Hanioka N, Yamamoto M, Iwabu H, Jinno H, Tanaka-Kagawa T, Naito S, Shimizu T, Masuda K, Katsu T, Narimatsu S. Functional characterization of human and cynomolgus monkey cytochrome P450 2E1 enzymes. Life Sci 2007; 81:1436-45. [DOI: 10.1016/j.lfs.2007.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2007] [Revised: 08/03/2007] [Accepted: 09/05/2007] [Indexed: 11/24/2022]
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Chen Y, Li G, Yin S, Xu J, Ji Z, Xiu X, Liu L, Ma D. Genetic polymorphisms involved in toxicant-metabolizing enzymes and the risk of chronic benzene poisoning in Chinese occupationally exposed populations. Xenobiotica 2007; 37:103-12. [PMID: 17178637 DOI: 10.1080/00498250601001662] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Benzene is a recognized haematotoxin and leukaemogen, but its mechanism of action and the role of genetic susceptibility are still unclear. Cytochrome P450 2E1 (CYP2E1) and myeloperoxidase (MPO) are involved in benzene activation; and NAD (P)H:quinine oxidoreductase 1 (NQO1), glutathione S-transferase theta 1 (GSTT1) and glutathione S-transferase mu 1 (GSTM1) participate in benzene detoxification. The common, well-studied single-nucleotide polymorphisms (SNPs) were analysed in these genes drawn from the toxicant-metabolizing pathways. A total of 100 workers with chronic benzene poisoning (CBP) and 90 controls were enrolled in China. There was a 2.82-fold (95% CI = 1.42-5.58) increased risk of CBP in the subjects with the NQO1 609C > T mutation genotype (T/T) compared with those carrying heterozygous (C/T) and wild-type (C/C). The subjects with the GSTT1 null genotype had a 1.91-fold (95% CI = 1.05-3.45) increased risk of CBP compared with those with GSTT1 non-null genotype. There was no association of CYP2E1 and MPO genotype with CBP. A three genes' interaction showed that there was a 20.41-fold (95% CI = 3.79-111.11) increased risk of CBP in subjects with the NQO1 609C > T T/T genotype and with the GSTT1 null genotype and the GSTM1 null genotype compared with those carrying the NQO1 609C > T C/T and C/C genotype, GSTT1 non-null genotype, and GSTM1 non-null genotype. The study provides evidence of an association of a gene-gene interaction with the risk of CBP.
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Affiliation(s)
- Y Chen
- College of Public Health, XinJiang Medical University, Urumqi, China.
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Ulusoy G, Arinç E, Adali O. Genotype and allele frequencies of polymorphic CYP2E1 in the Turkish population. Arch Toxicol 2007; 81:711-8. [PMID: 17380320 DOI: 10.1007/s00204-007-0200-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Accepted: 03/06/2007] [Indexed: 01/28/2023]
Abstract
Cytochrome P4502E1 (CYP2E1) gene shows genetic polymorphisms that vary markedly in frequency among different ethnic and racial groups. We studied the genotype distributions and allele frequencies of three CYP2E1 polymorphisms: CYP2E1*5B (RsaI/PstI RFLP, C-1053T/G-1293C SNP, rs2031920 /rs3813867), CYP2E1*6 (DraI RFLP, T7632A SNP, rs6413432), and CYP2E1*7B (DdeI RFLP, G-71T SNP, rs6413420) by PCR/RFLP technique in a sample of 206 healthy subjects representing Turkish population. CYP2E1*5B polymorphism analysis yielded the genotype distribution as 96.12% for *1A/*1A (c1/c1), and 3.88% for *1A/*5B (c1/c2). The genotype frequencies for CYP2E1*6 polymorphism were found as 83.98% for *1A/*1A (T/T), 15.53% for *1A/*6 (T/A) and 0.49% for *6/*6 (A/A). For CYP2E1*7B (G-71T) polymorphism, the genotype frequencies were determined to be 86.89% for *1A/*1A (G/G), 12.62% for *1A/*7B (G/T) and 0.49% for *7B/*7B (T/T). Accordingly, the allele frequencies for *5B, *6 and *7B were 1.94, 8.25, and 6.80%, respectively. The genotype distributions of CYP2E1*5B and *6 in Turkish population were similar to those in other Caucasian populations, while differed significantly from East Asian populations. Recently, a novel and functionally important CYP2E1*7B polymorphism was identified in the promoter region. There have been few studies and limited data on CYP2E1*7B polymorphism frequency in the world and, so far, no information has been available for Turkish population. The genotype frequencies of CYP2E1*7B in Turkish population were found to be similar to those of other Caucasian populations. Population studies like this could be useful in assessing the susceptibility of different populations to chemical-induced diseases, including several types of cancer.
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Affiliation(s)
- Gulen Ulusoy
- Biochemistry Graduate Programme and Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey
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Shadley JD, Divakaran K, Munson K, Hines RN, Douglas K, McCarver DG. Identification and functional analysis of a novel human CYP2E1 far upstream enhancer. Mol Pharmacol 2007; 71:1630-9. [PMID: 17353354 DOI: 10.1124/mol.106.031302] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Both transcriptional and post-transcriptional CYP2E1 regulatory mechanisms are known, resulting in 20-fold or greater variation in CYP2E1 expression. To evaluate functional regulatory elements controlling transcription, CYP2E1 promoter constructs were used to make adenovirus vectors containing CYP2E1 promoter-driven luciferase reporters for analyses in both primary human hepatocytes and HepG2 cells. A 1.2-kilobase pair portion of the CYP2E1 promoter was associated with 5- to 10-fold greater luciferase activity. This upstream region contained five direct repeats of 59 base pairs (bp) that increased thymidine kinase-driven luciferase reporter activity in HepG2 cells more than 5-fold, regardless of orientation. Electrophoretic mobility shift assays (EMSAs) identified sequence-specific nuclear protein binding to the 59-bp repeats that was dependent on a 17-bp sequence containing a canonical GATA binding site (WGATAR). Competitive and supershift EMSA identified the participation of GATA4, another GATA family member or GATA-like factor, and a third factor unrelated to the GATA family. Involvement of the tricho-rhino-phalangeal syndrome-1 factor, which also binds a GATA sequence, was eliminated. Rather, competitive EMSA using known binding sequences for the orphan nuclear receptors, steroidogenic factor-1 (or NR5A1), and fetoprotein transcription factor (or NR5A2) implicated an NR5A member in binding a sequence overlapping the canonical GATA. Chromatin immunoprecipitation assay demonstrated in vivo binding of NR5A2 to the enhancer sequence in human hepatocytes. The enhancer sequence is conserved within the human population but seems species-specific. The identification of this novel enhancer and its putative mechanism adds to the complexities of human CYP2E1 regulation.
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Affiliation(s)
- Jeff D Shadley
- Clinical Pharmacology, Pharmacogenetics & Teratology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226-4801, USA.
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Abstract
Bernard B. Brodie's laboratory was the first to examine the mechanisms of drug-induced toxicity at the molecular level. They found that acetaminophen hepatotoxicity was due to the metabolic activation of the drug to a highly reactive toxic metabolite that depleted cellular glutathione and covalently bound to protein. Subsequent studies revealed that activation of acetaminophen to an active metabolite is primarily carried out by CYP2E1, an ethanol-inducible cytochrome P450 that was first suggested by characterization of the microsomal ethanol oxidation system. CYP2E1 is developmentally regulated, under liver-specific control, and undergoes substrate-induced protein stabilization. It is also regulated by starvation and diabetes through insulin-dependent mRNA stabilization. In addition to acetaminophen, CYP2E1 metabolically activates a large number of low M(r) toxicants and carcinogens and thus is of great toxicological importance. The mechanism of regulation CYP2E1 and its role in acetaminophen toxicity will be discussed.
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Affiliation(s)
- Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Building 37/Room 3106, Bethesda, MD 20892, USA.
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Al-Dosari M, Zhang G, Knapp JE, Liu D. Direct Assessment of Promoter Activity of Human Cytochrome P450 Genes Using Optimized Transfection in Vitro and in Vivo. Biosci Rep 2006; 26:217-29. [PMID: 16850252 DOI: 10.1007/s10540-006-9017-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Although transcription regulation of human cytochrome P450 enzymes (CYP) is known to play an important role in drug metabolism and homeostasis, factors influencing the expression of various CYP genes in humans remain largely undefined. We used three cell lines and CD-1 mice to assess the activity of genomic promoter sequences of human CYP2D6, 1A2, 3A4, 2C9, 2C18, and 2E1 genes. CYP promoter sequences were amplified by PCR using human liver genomic DNA as the template and cloned into pGL3-Basic vectors that contain a luciferase reporter gene but lack promoter or enhancer sequences. Each plasmid construct was transfected into cells in vitro using polyethylenimine (PEI) as the transfection reagent and into mice using the recently developed hydrodynamics-based procedure. Relative promoter strength was determined by the level of luciferase expression in transfected cells. All six human CYP promoters are active in driving reporter gene expression in cultured hepatic HepG2 cells and non-hepatic cells such as human embryonic kidney fibroblasts (293 cells) and murine melanoma cells (BL-16) as well as cells in intact mouse liver, lung, heart, kidney and spleen. The order of strength among CYP promoters examined was found to be 2D6 > 1A2 > 3A4 > 2C9 > 2C18 > 2E1.
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Affiliation(s)
- Mohammed Al-Dosari
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, 527 Salk Hall, Pittsburgh, PA 15261, USA
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Yoon Y, Park HD, Park KU, Kim JQ, Chang YS, Song J. Associations between CYP2E1 promoter polymorphisms and plasma 1,3-dimethyluric acid/theophylline ratios. Eur J Clin Pharmacol 2006; 62:627-31. [PMID: 16841220 DOI: 10.1007/s00228-006-0165-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Accepted: 05/15/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Theophylline is metabolized to 1,3-dimethyluric acid (1,3-DMU), 3-methylxanthine, and 1-methylxanthine by CYP1A2 and partly by CYP2E1. Because 1,3-DMU is the major metabolite of theophylline, the 1,3-DMU/theophylline ratio is viewed as a good indicator of theophylline metabolic clearance. Here, we investigated the associations between 1,3-DMU/theophylline ratios and genetic polymorphisms of CYP2E1 and CYP1A2. METHODS Polymerase chain reaction (PCR) and direct sequencing or PCR-restriction fragment length polymorphism (RFLP) were performed to analyze CYP2E1 and CYP1A2 promoter polymorphisms in 62 Korean asthma patients. Plasma theophylline and 1,3-DMU levels were measured by liquid chromatography-tandem mass spectrometry. RESULTS Eleven polymorphisms including Ins(96), -1566 T>A, -1515 T>G, -1414 C>T, -1295 G>C, -1055 C>T, -1027 T>C, -930 A>G, -807 T>C, -352 A>G, and -333 T>A were detected in the 5' flanking region of the CYP2E1 gene (numbering according to GenBank Accession number NT_017795). Of these, five single nucleotide polymorphisms (SNPs) (-1566 T>A, -1295 G>C, -1055 C>T, -1027 T>C, and -807 T>C) were closely linked. Another three polymorphisms (Ins(96,) -930 A>G, and -352 A>G) and two polymorphisms (-1515 T>G and -333 T>A) were also closely linked. The five closely linked polymorphisms were associated with significantly different 1,3-DMU/theophylline ratios between heterozygotes plus homozygotes of a rare allele (n=23, 0.0368+/-0.0171) and common allelic homozygotes (n=39, 0.0533+/-0.0343) (p=0.024 by Mann-Whitney U test). In the CYP1A2 gene, the -2964G>A polymorphisms exhibited a significant difference in 1,3-DMU/theophylline levels between heterozygotes plus homozygotes of a rare allele (n=30, 0.0406+/-0.0272) and homozygotes of a common allele (n=32, 0.0534+/-0.0316) (p=0.032). CONCLUSION We confirm that hydroxylation at the 8 position of theophylline (1,3-DMU) is significantly affected by genetic polymorphism in CYP2E1 in addition to CYP1A2.
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Affiliation(s)
- Yeomin Yoon
- Department of Laboratory Medicine, Konkuk University College of Medicine, Seoul, South Korea
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Tsutsumi M, George J, Ishizawa K, Fukumura A, Takase S. Effect of chronic dietary ethanol in the promotion of N-nitrosomethylbenzylamine-induced esophageal carcinogenesis in rats. J Gastroenterol Hepatol 2006; 21:805-13. [PMID: 16704527 DOI: 10.1111/j.1440-1746.2005.04040.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND The pathogenetic correlation between chronic alcohol consumption and development of esophageal cancer is not clear. The role of alcohol abuse in the carcinogenic action of N-nitrosomethylbenzylamine, which induces tumors in the esophagus, has been evaluated. METHODS Twenty male rats were fed liquid diets containing ethanol or carbohydrates for 30 weeks. N-nitrosomethylbenzylamine (0.1 mg/kg, twice a week) was injected i.p. from the 9th to 19th week. The pair feeding was stopped at 9.00 am and N-nitrosomethylbenzylamine was administered at 10.00 am. Ethanol was not detected in the blood at the time of injection. Liquid diets were provided again at 3 pm until 9 am next day. The animals were killed at the end of the 30th week. The esophagi were collected and examined for visible tumors. The tissue sections were stained for histology and CYP2E1expression. RESULTS While 5-8 esophageal squamous polyps developed in all rats in the ethanol group, only one polyp each was formed in five out of the 10 rats in the control group. The size of the polyps was significantly larger in the ethanol group, when compared to the control group. Invasive squamous cell carcinoma was also observed in 50% of the animals in the ethanol group. Cytochrome P4502E1 (CYP2E1) staining demonstrated marked expression in the esophageal mucosa in the ethanol group, but not in the control group. CONCLUSIONS The increased expression of CYP2E1 induced by chronic ethanol consumption promotes the development of N-nitrosomethylbenzylamine-induced esophageal tumorigenesis. However, the molecular mechanism of the increased production of esophageal tumors during alternative administration of N-nitrosomethylbenzylamine and ethanol is not clear.
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Affiliation(s)
- Mikihiro Tsutsumi
- Division of Gastroenterology, Department of Internal Medicine, Kanazawa Medical University, Uchinada, Ishikawa, Japan.
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Rossini A, Lima SS, Rapozo DCM, Faria M, Albano RM, Pinto LFR. CYP2A6 and CYP2E1 polymorphisms in a Brazilian population living in Rio de Janeiro. Braz J Med Biol Res 2006; 39:195-201. [PMID: 16470306 DOI: 10.1590/s0100-879x2006000200005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytochrome P450 (CYP) is a superfamily of enzymes involved in the metabolism of endogenous compounds and xenobiotics. CYP2A6 catalyzes the oxidation of nicotine and the activation of carcinogens such as aflatoxin B1 and nitrosamines. CYP2E1 metabolizes ethanol and other low-molecular weight compounds and can also activate nitrosamines. The CYP2A6 and CYP2E1 genes are polymorphic, altering their catalytic activities and susceptibility to cancer and other diseases. A number of polymorphisms described are ethnic-dependent. In the present study, we determined the genotype and allele frequencies of the main CYP2A6 and CYP2E1 polymorphisms in a group of 289 volunteers recruited at the Central Laboratory of Hospital Universitário Pedro Ernesto. They had been residing in the city of Rio de Janeiro for at least 6 months and were divided into two groups according to skin color (white and non-white). The alleles were determined by allele specific PCR (CYP2A6) or by PCR-RFLP (CYP2E1). The frequencies of the CYP2A6*1B and CYP2A6*2 alleles were 0.29 and 0.02 for white individuals and 0.24 and 0.01 for non-white individuals, respectively. The CYP2A6*5 allele was not found in the population studied. Regarding the CYP2E1*5B allele, we found a frequency of 0.07 in white individuals, which was statistically different (P < 0.05) from that present in non-white individuals (0.03). CYP2E1*6 allele frequency was the same (0.08) in both groups. The frequencies of CYP2A6*1B, CYP2A6*2 and CYP2E1*6 alleles in Brazilians are similar to those found in Caucasians and African-Americans, but the frequency of the CYP2E1*5B allele is higher in Brazilians.
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Affiliation(s)
- A Rossini
- Departamento de Bioquímica, Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Al-Dosari M, Zhang G, Knapp JE, Liu D. Evaluation of viral and mammalian promoters for driving transgene expression in mouse liver. Biochem Biophys Res Commun 2006; 339:673-8. [PMID: 16316630 DOI: 10.1016/j.bbrc.2005.11.063] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Accepted: 11/11/2005] [Indexed: 11/22/2022]
Abstract
Fifteen luciferase plasmid constructs driven by various promoters including cytomegalovirus (CMV), Rous sarcoma virus (RSV), human serum albumin (SA), alpha-1 antitrypsin (AAT), cytochrome P450 CYP1A2, CYP2C9, CYP2C18, CYP2D6, CYP3A4, mouse CYP2b10, human amyloid precursor protein (APP), chicken beta actin (ACT), nuclear factor kappa B (NFkappaB), and heat shock protein 70 (HS) promoters were hydrodynamically introduced into mouse hepatocytes, and the level and persistence of luciferase gene expression were examined. Eight hours post-gene transfer, the CMV and AAT promoters showed the highest activity, followed by the CYP2D6, HS, and RSV promoters which were slightly less active. The human serum albumin promoter exhibited the lowest activity among the promoters examined. The time course of gene expression showed a two-phase decline in luciferase activity with a rapid phase within the first 5-7 days and a slower decline thereafter. Results from Southern and Northern blot analyses revealed a good correlation between the decline of luciferase activity and the decrease in mRNA level, suggesting promoter silencing as the possible mechanism for the observed transient luciferase gene expression. Inclusion of EBN1 and oriP sequences of Epstein-Barr virus into the plasmid extended the period of active transcription for about one week. These results provide important information concerning the role of promoters in regulating transgene expression and for the proper design of plasmids for gene expression and gene therapy.
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Affiliation(s)
- Mohammed Al-Dosari
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA 15261, USA
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Bauer M, Herbarth O, Aust G, Graebsch C. Molecular cloning and expression of novel alternatively spliced cytochrome P450 2E1 mRNAs in humans. Mol Cell Biochem 2005; 280:201-7. [PMID: 16311924 DOI: 10.1007/s11010-005-0169-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Accepted: 06/23/2005] [Indexed: 12/26/2022]
Abstract
Human cytochrome P450 2E1 (CYP2E1) is a phase I metabolizing enzyme. It is involved in the biotransformation of xenobiotics and endogenous substrates. Inter-individual genetic polymorphisms of the CYP2E1 gene are associated with different cancer diseases as well as alcohol and nicotine dependence. We report here for the first time three novel alternative spliced mRNA transcripts which are more frequently present in lung carcinoma cell lines as in hepatocyte cell lines. They are unexpected detectable in blood leukocytes from healthy volunteers but not in normal and cancerous lung tissue. The full-length wildtype transcript of CYP2E1 is described to be concomitant to an alternatively spliced mRNA transcript. Stimulation with CYP2E1-inducing agents did not change the splicing transcript pattern. The three splicing variants should lead to truncated non-functional proteins. Thus the genetic diversity of CYP2E1 is additionally extended at the transcriptional level of gene expression. The physiological role of the splicing variants is not known, yet, but they seem to be related to the carcinogenic property of the cell lines.
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Affiliation(s)
- Mario Bauer
- Department of Human Exposure Research and Epidemiology, UFZ - Centre for Environmental Research Leipzig-Halle, Permoser street 15, 04318, Leipzig, Germany.
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Fairhead M, Giannini S, Gillam EMJ, Gilardi G. Functional characterisation of an engineered multidomain human P450 2E1 by molecular Lego. J Biol Inorg Chem 2005; 10:842-53. [PMID: 16283395 DOI: 10.1007/s00775-005-0033-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 09/12/2005] [Indexed: 11/24/2022]
Abstract
The human cytochrome P450s constitute an important family of monooxygenase enzymes that carry out essential roles in the metabolism of endogenous compounds and foreign chemicals. We present here results of a fusion between a human P450 enzyme and a bacterial reductase that for the first time is shown does not require the addition of lipids or detergents to achieve wild-type-like activities. The fusion enzyme, P450 2E1-BMR, contains the N-terminally modified residues 22-493 of the human P450 2E1 fused at the C-terminus to residues 473-1049 of the P450 BM3 reductase (BMR). The P450 2E1-BMR enzyme is active, self-sufficient and presents the typical marker activities of the native human P450 2E1: the hydroxylation of p-nitrophenol (KM=1.84+/-0.09 mM and kcat of 2.98+/-0.04 nmol of p-nitrocatechol formed per minute per nanomole of P450) and chlorzoxazone (KM=0.65+/-0.08 mM and kcat of 0.95+/-0.10 nmol of 6-hydroxychlorzoxazone formed per minute per nanomole of P450). A 3D model of human P450 2E1 was generated to rationalise the functional data and to allow an analysis of the surface potentials. The distribution of charges on the model of P450 2E1 compared with that of the FMN domain of BMR provides the ground for the understanding of the interaction between the fused domains. The results point the way to successfully engineer a variety of catalytically self-sufficient human P450 enzymes for drug metabolism studies in solution.
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Affiliation(s)
- Michael Fairhead
- Division of Molecular Biosciences, Faculty of Life Sciences, Imperial College London, South Kensington, SW7 2AZ, London, UK
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Cartmell MT, Schulz HU, O'Reilly DA, Yang BM, Kielstein V, Dunlop SP, Halangk W, Demaine AG, Kingsnorth AN. Cytochrome P450 2E1 high activity polymorphism in alcohol abuse and end-organ disease. World J Gastroenterol 2005; 11:6445-9. [PMID: 16425414 PMCID: PMC4355784 DOI: 10.3748/wjg.v11.i41.6445] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 04/01/2005] [Accepted: 04/02/2005] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate a possible role for a recently identified polymorphism in the gene of cytochrome P450 2E1, the presence of which is associated with high activity of the enzyme. METHODS Two hundred and thirty-nine alcohol consumers, ICD 10.1/.2 (ALC), and 208 normal controls were studied. PCR amplification of the CYP2E1 gene region was performed to assess polymorphic variation. Fisher's exact test was used to assess the data. RESULTS Twelve normal controls (5.8%) possessed the insertion. Five ALC (2.1%) had the insertion; of these 2 of 144 with alcohol induced chronic pancreatitis, none of 28 with alcoholic liver disease and 3 of 67 without end-organ disease had the polymorphism. A significantly Lower frequency of subjects possessed the insertion than normal controls [P=0.049 (genotype analysis P=0.03)]. To further assess, if there was a relationship to alcohol problems per se or end-organ disease, we compared patients with alcohol induced end-organ disease vs alcoholic controls without end-organ disease vs normal controls which again showed a significant difference [P=0.045 (genotype analysis, P=0.011)], further sub-group analysis did not identify which group(s) accounted for these differences. CONCLUSION We have shown the frequencies of this high-activity polymorphism in alcohol related patient groups for the first time. The frequency is significantly less in alcoholics than normal controls, as with high activity polymorphisms of alcohol dehydrogenase. The biological significance, and whether the relevance is solely for alcoholism or is there a relationship to end-organ disease, would benefit from the assessment in the populations with a greater frequency of this polymorphism.
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Affiliation(s)
- Mark T Cartmell
- Department of Surgery, Derriford Hospital, and Department of Molecular Medicine, Plymouth Postgraduate Medical School, PL6 8DH, United Kingdom.
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Cheung C, Yu AM, Ward JM, Krausz KW, Akiyama TE, Feigenbaum L, Gonzalez FJ. The cyp2e1-humanized transgenic mouse: role of cyp2e1 in acetaminophen hepatotoxicity. Drug Metab Dispos 2004; 33:449-57. [PMID: 15576447 DOI: 10.1124/dmd.104.002402] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The cytochrome P450 (P450) CYP2E1 enzyme metabolizes and activates a wide array of toxicological substrates, including alcohols, the widely used analgesic acetaminophen, acetone, benzene, halothane, and carcinogens such as azoxymethane and dimethylhydrazine. Most studies on the biochemical and pharmacological actions of CYP2E1 are derived from studies with rodents, rabbits, and cultured hepatocytes; therefore, extrapolation of the results to humans can be difficult. Creating "humanized" mice by introducing the human CYP2E1 gene into Cyp2e1-null mice can circumvent this disadvantage. A transgenic mouse line expressing the human CYP2E1 gene was established. Western blot and high-performance liquid chromatography/mass spectrometry analyses revealed human CYP2E1 protein expression and enzymatic activity in the liver of CYP2E1-humanized mice. Treatment of mice with the CYP2E1 inducer acetone demonstrated that human CYP2E1 was inducible in this transgenic model. The response to the CYP2E1 substrate acetaminophen was explored in the CYP2E1-humanized mice. Hepatotoxicity, resulting from the CYP2E1-mediated activation of acetaminophen, was demonstrated in the livers of CYP2E1-humanized mice by elevated serum alanine aminotransferase levels, increased hepatocyte necrosis, and decreased P450 levels. These data establish that in this humanized mouse model, human CYP2E1 is functional and can metabolize and activate different CYP2E1 substrates such as chlorzoxazone, p-nitrophenol, acetaminophen, and acetone. CYP2E1-humanized mice will be of great value for delineating the role of human CYP2E1 in ethanol-induced oxidative stress and alcoholic liver damage. They will also function as an important in vivo tool for predicting drug metabolism and disposition and drug-drug interactions of chemicals that are substrates for human CYP2E1.
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Affiliation(s)
- Connie Cheung
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Building 37, Room 3106, 9000 Rockville Pike, Bethesda, MD 20892, USA
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Abdel-Razzak Z, Garlatti M, Aggerbeck M, Barouki R. Determination of interleukin-4-responsive region in the human cytochrome P450 2E1 gene promoter. Biochem Pharmacol 2004; 68:1371-81. [PMID: 15345327 DOI: 10.1016/j.bcp.2004.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Accepted: 06/04/2004] [Indexed: 11/26/2022]
Abstract
Cytochrome P450 2E1 (CYP2E1) gene expression is known to be induced by interleukin-4 (IL4) and repressed by inflammatory cytokines, such as interleukin-1beta3 (IL1beta3) in human hepatocytes. The mechanisms involved in these transcriptional regulations remain elusive. In order to study these mechanisms, various constructs of the human CYP2E1 promoter were prepared and transfected into the human HepG2 hepatoma cell line. Our findings revealed that an IL4-responsive region of 128bp (-671/-544) was required to mediate induction by IL4. IL1beta caused moderate but significant decrease of the promoter activity, which was abolished when the two cytokines were combined. The IL1beta inhibitory effect is mediated through a regulatory sequence independent of that of IL4. Furthermore, by using specific signaling pathway inhibitors, we demonstrated that IL4 activation required protein kinase C (PKC) activation. In addition, our results suggest that induction by IL4 was not dependent on a single binding site but rather on a complex region which includes putative binding sites for signal transducer and activator of transcription (STAT)6, activator protein (AP)-1, nuclear factor kappa-B (NFkappaB), nuclear factor of activated T cells (NFAT) and CCAAT enhancer binding protein (C/EBP). Electrophoretic mobility shift assays suggest that AP1 and NFAT transcription factors are able to bind to three sites in the IL4-responsive region.
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Yamazaki Y, Fujita KI, Nakayama K, Suzuki A, Nakamura K, Yamazaki H, Kamataki T. Establishment of ten strains of genetically engineered Salmonella typhimurium TA1538 each co-expressing a form of human cytochrome P450 with NADPH-cytochrome P450 reductase sensitive to various promutagens. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2004; 562:151-62. [PMID: 15279838 DOI: 10.1016/j.mrgentox.2004.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Revised: 06/10/2004] [Accepted: 06/10/2004] [Indexed: 10/26/2022]
Abstract
We newly developed 10 Salmonela typhimurium TA1538 strains each co-expressing a form of human cytochrome P450s (P450 or CYP) together with NADPH-cytochrome P450 reductase (CPR) for highly sensitive detection of mutagenic activation of mycotoxins, polycyclic aromatic hydrocarbons, heterocyclic amines, and aromatic amines at low substrate concentrations. Each form of P450 (CYP1A1, CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4 or CYP3A5) expressed in the TA1538 cells efficiently catalyzed the oxidation of a representative substrate. Aflatoxin B1 was mutagenically activated effectively by CYP1A1, CYP1A2, and CYP3A4 and weakly by CYP2A6 and CYP2C8 expressed in S. typhimurium TA1538. CYP1A1 and CYP1A2 were responsible for the mutagenic activation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-acetylaminofluorene. Benzo[a]pyrene was also activated efficiently by CYP1A1 and weakly by CYP1A2, CYP2C9, CYP2C19, and CYP3A4 expressed in TA1538. These results suggest that the newly developed S. typhimurium TA1538 strains are applicable for detecting the activation of promutagens of which mutagenic activation is not or weakly detectable with N-nitrosamine-sensitive YG7108 strains expressing human P450s.
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Affiliation(s)
- Yoshiyuki Yamazaki
- Laboratory of Drug Metabolism, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
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Lieber CS. Alcoholic fatty liver: its pathogenesis and mechanism of progression to inflammation and fibrosis. Alcohol 2004; 34:9-19. [PMID: 15670660 DOI: 10.1016/j.alcohol.2004.07.008] [Citation(s) in RCA: 423] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Revised: 07/16/2004] [Accepted: 07/20/2004] [Indexed: 02/06/2023]
Abstract
Liver disease in the alcoholic is due not only to malnutrition but also to ethanol's hepatotoxicity linked to its metabolism by means of the alcohol dehydrogenase and cytochrome P450 2E1 (CYP2E1) pathways and the resulting production of toxic acetaldehyde. In addition, alcohol dehydrogenase-mediated ethanol metabolism generates the reduced form of nicotinamide adenine dinucleotide (NADH), which promotes steatosis by stimulating the synthesis of fatty acids and opposing their oxidation. Steatosis is also promoted by excess dietary lipids and can be attenuated by their replacement with medium-chain triglycerides. Through reduction of pyruvate, elevated NADH also increases lactate, which stimulates collagen synthesis in myofibroblasts. Furthermore, CYP2E1 activity is inducible by its substrates, not only ethanol but also fatty acids. Their excess and metabolism by means of this pathway generate release of free radicals, which cause oxidative stress, with peroxidation of lipids and membrane damage, including altered enzyme activities. Products of lipid peroxidation such as 4-hydroxynonenal stimulate collagen generation and fibrosis, which are further increased through diminished feedback inhibition of collagen synthesis because acetaldehyde forms adducts with the carboxyl-terminal propeptide of procollagen in hepatic stellate cells. Acetaldehyde is also toxic to the mitochondria, and it aggravates their oxidative stress by binding to reduced glutathione and promoting its leakage. Oxidative stress and associated cellular injury promote inflammation, which is aggravated by increased production of the proinflammatory cytokine tumor necrosis factor-alpha in the Kupffer cells. These are activated by induction of their CYP2E1 as well as by endotoxin. The endotoxin-stimulated tumor necrosis factor-alpha release is decreased by dilinoleoylphosphatidylcholine, the active phosphatidylcholine (PC) species of polyenylphosphatidylcholine (PPC). Moreover, defense mechanisms provided by peroxisome proliferator-activated receptor alpha and omega fatty acid oxidation are readily overwhelmed, particularly in female rats and also in women who have low hepatic induction of fatty acid-binding protein (L-FABPc). Accordingly, the intracellular concentration of free fatty acids may become high enough to injure membranes, thereby contributing to necrosis, inflammation, and progression to fibrosis and cirrhosis. Eventually, hepatic S-adenosylmethionine and PCs become depleted in the alcoholic, with impairment of their multiple cellular functions, which can be restored by PC replenishment. Thus, prevention and therapy opposing the development of steatosis and its progression to more severe injury can be achieved by a multifactorial approach: control of alcohol consumption, avoidance of obesity and of excess dietary long-chain fatty acids, or their replacement with medium-chain fatty acids, and replenishment of S-adenosylmethionine and PCs by using PPC. Progress in the understanding of the pathogenesis of alcoholic fatty liver and its progression to inflammation and fibrosis has resulted in prospects for their better prevention and treatment.
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Man XB, Tang L, Qiu XH, Yang LQ, Cao HF, Wu MC, Wang HY. Expression of cytochrome P4502E1 gene in hepatocellular carcinoma. World J Gastroenterol 2004; 10:1565-8. [PMID: 15162526 PMCID: PMC4572755 DOI: 10.3748/wjg.v10.i11.1565] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: To investigate cytpchrome P4502E1 (CYP2E1) gene expression in occurrence and progression of hepatocellular carcinoma (HCC).
METHODS: The human liver arrayed library was spotted onto the nylon membranes to make cDNA array. Hybridization of cDNA array was performed with labeled probes synthesized from RNA isolated from HCC and adjacent liver tissues. Sprague-Dawley rats were administrated diethylnitrosamine (DENA) to induce HCC. CYP2E1 expression was detected by the method of RT-PCR and Northern blot analysis.
RESULTS: CYP2E1 was found by cDNA array hybridization to express differently between HCC and liver tissues. CYP2E1 only expressed in liver, but did not express in HCC tissues and expressed lowly in cirrhotic tissues. In the progression of cirrhosis and HCC, the expression level of CYP2E1 was gradually decreased and hardly detected until the late stage of HCC.
CONCLUSION: Using arrayed library to make cDNA arrays is an effective method to find differential expression genes. CYP2E1 is a unique gene expressing in liver but did not express in HCC. CYP2E1 expression descended along with the initiation and progression of HCC, which is noteworthy further investigations in its significance in the development of HCC.
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Affiliation(s)
- Xiao-Bo Man
- International Co-operation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, 225 Changhai Road, Shanghai 200438, China
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