1
|
Otsuki A, Okamura Y, Ishida N, Tadaka S, Takayama J, Kumada K, Kawashima J, Taguchi K, Minegishi N, Kuriyama S, Tamiya G, Kinoshita K, Katsuoka F, Yamamoto M. Construction of a trio-based structural variation panel utilizing activated T lymphocytes and long-read sequencing technology. Commun Biol 2022; 5:991. [PMID: 36127505 PMCID: PMC9489684 DOI: 10.1038/s42003-022-03953-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 09/06/2022] [Indexed: 11/13/2022] Open
Abstract
Long-read sequencing technology enable better characterization of structural variants (SVs). To adapt the technology to population-scale analyses, one critical issue is to obtain sufficient amount of high-molecular-weight genomic DNA. Here, we propose utilizing activated T lymphocytes, which can be established efficiently in a biobank to stably supply high-grade genomic DNA sufficiently. We conducted nanopore sequencing of 333 individuals constituting 111 trios with high-coverage long-read sequencing data (depth 22.2x, N50 of 25.8 kb) and identified 74,201 SVs. Our trio-based analysis revealed that more than 95% of the SVs were concordant with Mendelian inheritance. We also identified SVs associated with clinical phenotypes, all of which appear to be stably transmitted from parents to offspring. Our data provide a catalog of SVs in the general Japanese population, and the applied approach using the activated T-lymphocyte resource will contribute to biobank-based human genetic studies focusing on SVs at the population scale. Long-read sequencing on activated T-cells from a sample of 333 Japanese individuals (representing 111 parent-offspring trios) provides a useful reference dataset of structural variation in the Japanese population.
Collapse
Affiliation(s)
- Akihito Otsuki
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Yasunobu Okamura
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Noriko Ishida
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Shu Tadaka
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Jun Takayama
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project, Nihonbashi 1-chome Mitsui Building 15 F, 1-4-1 Nihonbashi, Chuo-ku, Tokyo, 103-0027, Japan.,Department of AI and Innovative Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Kazuki Kumada
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Junko Kawashima
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Keiko Taguchi
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.,Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Naoko Minegishi
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Shinichi Kuriyama
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Gen Tamiya
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project, Nihonbashi 1-chome Mitsui Building 15 F, 1-4-1 Nihonbashi, Chuo-ku, Tokyo, 103-0027, Japan.,Department of AI and Innovative Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Kengo Kinoshita
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.,Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Graduate School of Information Sciences, Tohoku University, 6-3-09 Aramaki Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Fumiki Katsuoka
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.,Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan
| | - Masayuki Yamamoto
- Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan. .,Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan. .,Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8573, Japan.
| |
Collapse
|
2
|
Soeroso N, Zain-Hamid R, Bihar S, Tarigan SP, Ananda FR. Genetic Polymorphism of Cyp2a6 and Cyp2a13 Genes and Environmental Tobacco Smoke Induced Lung Cancer Risk in Indonesian Female Never Smokers. Open Access Maced J Med Sci 2021. [DOI: 10.3889/oamjms.2021.6069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND: The presence of nicotine metabolite in the urine of subjects exposed to tobacco smoke represents the nicotine metabolism activity in environmental tobacco smokers. CYP2A6 and CYP2A13 are known as the main enzymes responsible for nicotine metabolism and xenobiotic activity in tobacco smoke-related lung cancer.
AIM: The aim of this study is to analyze the relationship between genetic polymorphism of CYP26 and CYP2A13 genes and environmental tobacco smoke-induced lung cancer risk in Indonesian females never smoker.
METHODS: This is a case-control study with two-stage of distinguishing polymorphism detection. Restriction fragment length polymorphism polymerase chain reaction from venous blood extraction was performed to examine the CYP2A6 and CYP2A13 polymorphism. Logistic regression test in Epi Info-7 software was carried out to examine genetic polymorphism of CYP2A6 and CYP2A13 genes and environmental tobacco smoke-induced lung cancer risk in Indonesian female never smokers.
RESULTS: A total of 203 participants enrolled in this study with the first stage of CYP2A6 polymorphism involved 101 subjects showed no significant correlation between the genotypes of CYP2A6 and the incidence of lung cancer. On the other hand, there was a significant correlation between genotypes of CYP2A13 and the incidence of lung cancer (p < 0.05). People with the genotype CT have a 2.7 higher risk for developing lung cancer compare with genotype CC. Allele *1B was the most common allele in CYP2A6. Allele C has more frequencies and has 0.62 times the risk for developing lung cancer compared with allele T with a wide range of confidence intervals (0.73–3.52).
CONCLUSIONS: There was a significant correlation between polymorphism CYP213 with the incidence of lung cancer among female lung cancer never smoker. However, the results show no significant relationship between CYP2A6 genetic polymorphism and lung cancer incidence.
Collapse
|
3
|
Soeroso NN, Zain-Hamid R, Sinaga BYM, Sadewa AH, Syafiuddin T, Syahruddin E, Tann G, Mutiara E. Genetic Polymorphism of CYP2A6 and Its Relationship with Nicotine Metabolism in Male Bataknese Smokers Suffered from Lung Cancer in Indonesia. Open Access Maced J Med Sci 2018; 6:1199-1205. [PMID: 30087722 PMCID: PMC6062282 DOI: 10.3889/oamjms.2018.259] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/22/2018] [Accepted: 05/25/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Cytochrome P450 2A6 (CYP2A6) is known as an enzyme which is responsible for the metabolism of chemical compounds. AIM This study aimed to analyse the relationship between CYP2A6 gene polymorphism with nicotine metabolism rates and lung cancer incidence among smokers of Batak ethnic group in Indonesia. METHODS This study was a case-control study involving 140 research subjects through a purposive sampling technique from three hospitals in Medan, Indonesia. An examination of nicotine metabolism rates was conducted for all subjects using the 3HC/cotinine ratio parameter with LC-MS/MS technique. The examination of the CYP2A6 gene was performed with PCR-RFLP. Data were analysed with Conditional Logistic Regression test using Epi Info 7.0 software. RESULTS The allele frequencies of CYP2A6*1A, CYP2A6*1B, and CYP2A6*4A found were 44.3%, 48.9%, and 6.8%, respectively. The *1B allele showed the highest metabolism rate. It is found that slow metabolizer individuals were 5.49 times more likely to develop lung cancer (P = 0.01, 95%CI 1.2-24.8). CONCLUSION Among the Bataknese smokers studied, the CYP2A6*1B allele was found to be the most common allele and showed the highest rate of nicotine metabolism. However, the results show the insignificant relationship among CYP2A6 genetic polymorphism, nicotine metabolism, and lung cancer incidence.
Collapse
Affiliation(s)
- Noni Novisari Soeroso
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Rozaimah Zain-Hamid
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Bintang Y M Sinaga
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Ahmad Hamim Sadewa
- Department of Biochemistry, Faculty of Medicine, Gadjah Mada University, Jl. Farmako Sekip Utara, Yogyakarta 55281, Indonesia
| | - Tamsil Syafiuddin
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Elisna Syahruddin
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Indonesia, Jl. Persahabatan Raya No.1, Jakarta 13230, Indonesia
| | - Gino Tann
- Department of Clinical Pathology, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Erna Mutiara
- Department of Biostatistics, Faculty of Public Health, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| |
Collapse
|
4
|
Soeroso NN, Zain-Hamid R, Sinaga BYM, Sadewa AH, Syafiuddin T, Syahruddin E, Tann G, Mutiara E. The Role of CYP2A6 Genetic Polymorphism in Nicotine Dependence and Tobacco Consumption among Bataknese Male Smokers. Open Access Maced J Med Sci 2018; 6:864-866. [PMID: 29875862 PMCID: PMC5985876 DOI: 10.3889/oamjms.2018.224] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 11/05/2022] Open
Abstract
AIM: This research aimed to analyse the relationship between CYP2A6 gene polymorphism with nicotine dependence and its relation to the number of cigarette consumption among Bataknese smokers. METHOD: This study was a cross-sectional study involving 140 research subjects in Medan, Indonesia. RESULTS: Nicotine dependence rates were found to be significantly associated with the number of cigarette consumption expressed in the Brinkman Index. CONCLUSION: The *1A wild-type alleles have a greater risk of high-very high dependence rate compared to the other variants.
Collapse
Affiliation(s)
- Noni Novisari Soeroso
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Rozaimah Zain-Hamid
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Bintang Y M Sinaga
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Ahmad Hamim Sadewa
- Department of Biochemistry, Faculty of Medicine, Gadjah Mada University, Jl. Farmako Sekip Utara, Yogyakarta 55281, Indonesia
| | - Tamsil Syafiuddin
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Elisna Syahruddin
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Indonesia, Jl. Persahabatan Raya No.1, Jakarta 13230, Indonesia
| | - Gino Tann
- Department of Clinical Pathology, Faculty of Medicine, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| | - Erna Mutiara
- Department of Biostatistics, Faculty of Public Health, University of Sumatera Utara, Jl. Dr Mansyur No.5 Medan 20155, Indonesia
| |
Collapse
|
5
|
López-Flores LA, Pérez-Rubio G, Falfán-Valencia R. Distribution of polymorphic variants of CYP2A6 and their involvement in nicotine addiction. EXCLI JOURNAL 2017; 16:174-196. [PMID: 28507465 PMCID: PMC5427481 DOI: 10.17179/excli2016-847] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/13/2017] [Indexed: 01/08/2023]
Abstract
Tobacco consumption has become a major public health issue, which has motivated studies to identify and understand the biological processes involved in the smoking behavior for prevention and smoking cessation treatments. CYP2A6 has been identified as the main gene that codifies the enzyme that metabolizes nicotine. Many alleles have been identified after the discovery of CYP2A6, suggesting a wide interethnic variability and a diverse smoking behavior of the allele carrying individuals. The main purpose of this review is to update and highlight the effects of the CYP2A6 gene variability related to tobacco consumption reported from diverse human populations. The review further aims to consider CYP2A6 in future studies as a possible genetic marker for the prevention and treatment of nicotine addiction. Therefore, we analyzed several population studies and their importance at addressing and characterizing a population using specific parameters. Our efforts may contribute to a personalized system for detecting, preventing and treating populations at a higher risk of smoking to avoid diseases related to tobacco consumption.
Collapse
|
6
|
Svyryd Y, Ramírez-Venegas A, Sánchez-Hernández B, Aguayo-Gómez A, Luna-Muñoz L, Arteaga-Vázquez J, Regalado-Pineda J, Mutchinick OM. Genetic Risk Determinants for Cigarette Smoking Dependence in Mexican Mestizo Families. Nicotine Tob Res 2015; 18:620-5. [PMID: 26416825 DOI: 10.1093/ntr/ntv213] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 09/12/2015] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Tobacco smoking is a leading cause of mortality in developed and developing countries. Despite antitobacco and smoke-free policies, the prevalence of active smokers in Mexican urban populations has remained stable. Mexican smokers differ from Caucasian and other ethnic groups, probably due to sociocultural and genetic background characteristics. This study explored the effect of known genetic variants on smoking behavior in Mexico City residents. METHODS Three hundred sixty-four Mexican Mestizo Mexico City residents from 87 families with at least one smoker were assessed for association of 12 gene variants of six candidate genes (CHRNA4, CHRNB2, DRD2, ANKK1, SLC6A3, and CYP2A6) with cigarette consumption, age of initiation and smoking duration. The Family Based Association Test, an extension of the Transmission Disequilibrium Test, was used to perform family-based association analysis. RESULTS The Family Based Association Test showed statistically significant association between the rs2072658 polymorphism of the CHRNB2 gene and smoking-related phenotypes such as: smoking status (SS), age of onset (AO), years of smoking, and psychological dependence (PD) evaluated by the Glover-Nilsson Smoking Behavior Questionnaire. After Bonferroni correction, only the association with AO remained significant (P = .003). Statistically significant association was also observed for the CYP2A6 rs28399433 T allele with SS (P = .003) and PD (P = .003). CONCLUSIONS Our results indicate effects of the rs2072658 CHRNB2 and rs28399433 CYP2A6 gene variants on AO, SS and PD in Mexican Mestizo smokers. A mild effect of other analyzed gene variants, which may contribute to a putative polygenic predisposition for smoking, is suggested. IMPLICATIONS The understanding of genetic and environmental determinants in the Mexican population is important for other Latin American populations as well, living in their own countries or moving to other ones, particular due to the current migration characteristics and particular genetic background like the Mexican Mestizo and other Central American populations with similar characteristics and migrating to neighbor developed countries, introducing their own smoking behavior and contributing importantly to the genetic pool of the receptor country.
Collapse
Affiliation(s)
- Yevgeniya Svyryd
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | - Alejandra Ramírez-Venegas
- Department of Smoking Research, Instituto Nacional de Enfermedades Respiratorias, México, D.F., México
| | - Beatriz Sánchez-Hernández
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | - Adolfo Aguayo-Gómez
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | - Leonora Luna-Muñoz
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | - Jazmín Arteaga-Vázquez
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | | | - Osvaldo M Mutchinick
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México;
| |
Collapse
|
7
|
Ito T, Tsuji M, Mori Y, Kanda H, Hidaka T, Kakamu T, Kumagai T, Hayakawa T, Osaki Y, Fukushima AT. EFFECT OF CYP2A6*4 GENETIC POLYMORPHISMS ON SMOKING BEHAVIORS AND NICOTINE DEPENDENCE IN A GENERAL POPULATION OF JAPANESE MEN. Fukushima J Med Sci 2015; 61:125-30. [PMID: 26370685 DOI: 10.5387/fms.2015-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Nicotine in cigarettes is metabolized primarily by CYP2A6-catalyzed oxidation. The CYP2A6*4 allele, in which CYP2A6 is a homozygous whole-deletion variant, completely lacks enzyme activity. The aim of this study was to examine the effects of CYP2A6*4 genetic polymorphism on smoking behavior and nicotine dependence in a general population of Japanese men. METHODS The subjects were 124 healthy Japanese men who gave informed consent to give saliva samples. The survey items included general information, smoking behaviors and nicotine dependence. The polymerase chain reaction restriction fragment length polymorphism method was used to analyze the genetic polymorphisms of CYP2A6. The subjects were classified into two groups: Group W (CYP2A6*4 absence: *1A/*1A, *1A/*1B and *1B/*1B) and Group D (CYP2A6*4 presence: *1B/*4A, *4A/*4A, *1A/*4A or *1B/*4D, and *1A/*4D). We analyzed the differences in the survey items between the two groups. RESULTS There were no significant differences in smoking behaviors between the two groups. However, Group D tended to have less difficulty in refraining from smoking after waking in the morning compared to Group W (p=0.051). CONCLUSIONS CYP2A6*4 genetic polymorphisms may not strongly affect smoking behavior but may possibly have an effect on nicotine dependence.
Collapse
Affiliation(s)
- Teruna Ito
- Department of Hygiene and Preventive Medicine, Fukushima Medical University School of Medicine
| | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Alessandrini M, Pepper MS. Priority pharmacogenetics for the African continent: focus on CYP450. Pharmacogenomics 2014; 15:385-400. [PMID: 24533717 DOI: 10.2217/pgs.13.252] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Countries in Africa have a high burden of communicable disease, and are experiencing an increase in noncommunicable diseases due to the effects of globalization, industrialization and urbanization. The costs incurred through adverse drug reactions and nonresponsiveness to therapy further aggravates the situation, and the application of pharmacogenetic principles is likely to provide some relief. Having undertaken an extensive evaluation of CYP450 reports in Africa, our objective was to map out areas of need based on regional disease burdens. The data confirms a paucity of CYP450 reports and illustrates large regions for which no population information exists. There is a dire need to address the health problems of Africa, and wide-scale pharmacogenetic profiling of these populations will add significantly to improving patient care on the continent. Priority pharmacogenetics for the African continent gives precedence to the profiling of clinically relevant pharmacogenetic biomarkers, and defines the immediate need in the context of disease burden.
Collapse
Affiliation(s)
- Marco Alessandrini
- Department of Immunology & The Institute for Cellular & Molecular Medicine, Faculty of Health Sciences, University of Pretoria, South Africa
| | | |
Collapse
|
9
|
Yamamiya I, Yoshisue K, Ishii Y, Yamada H, Chiba M. Effect of CYP2A6 genetic polymorphism on the metabolic conversion of tegafur to 5-fluorouracil and its enantioselectivity. Drug Metab Dispos 2014; 42:1485-92. [PMID: 25002745 DOI: 10.1124/dmd.114.058008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tegafur (FT), a prodrug of 5-fluorouracil, is a chiral molecule, a racemate of R- and S-isomers, and CYP2A6 plays an important role in the enantioselective metabolism of FT in human liver microsomes (R-FT >> S-FT). This study examined the enantioselective metabolism of FT by microsomes prepared from Sf9 cells expressing wild-type CYP2A6 and its variants (CYP2A6*7, *8, *10, and *11) that are highly prevalent in the Asian population. We also investigated the metabolism of coumarin and nicotine, both CYP2A6 probe drugs, in these variants. Enzyme kinetic analyses showed that CYP2A6.7 (I471T) and CYP2A6.10 (I471T and R485L) had markedly lower Vmax values for both enantiomers than wild-type enzyme (CYP2A6.1) and other variant enzymes, whereas Km values were higher in most of the variant enzymes for both enantiomers than CYP2A6.1. The ratios of Vmax and Km values for R-FT to corresponding values for S-FT (R/S ratio) were similar among enzymes, indicating little difference in enantioselectivity among the wild-type and variant enzymes. Similarly, both CYP2A6.7 and CYP2A6.10 had markedly lower Vmax values for coumarin 7-hydroxylase and nicotine C-oxidase activities than CYP2A6.1 and other variant enzymes, whereas Km values were higher in most of the variant enzymes for both activities than CYP2A6.1. In conclusion, the amino acid substitutions in CYP2A6 variants generally resulted in lower affinity for substrates, while Vmax values were selectively reduced in CYP2A6.7 and CYP2A6.10. Consistent R/S ratios among CYP2A6.1 and variant enzymes indicated that the amino acid substitutions had little effect on enantioselectivity in the metabolism of FT.
Collapse
Affiliation(s)
- Ikuo Yamamiya
- Pharmacokinetics Research Laboratories, Taiho Pharmaceutical Co., Ltd., Tsukuba, Japan (I.Y., K.Y., M.C.); and Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan (I.Y., Y.I., H.Y.)
| | - Kunihiro Yoshisue
- Pharmacokinetics Research Laboratories, Taiho Pharmaceutical Co., Ltd., Tsukuba, Japan (I.Y., K.Y., M.C.); and Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan (I.Y., Y.I., H.Y.)
| | - Yuji Ishii
- Pharmacokinetics Research Laboratories, Taiho Pharmaceutical Co., Ltd., Tsukuba, Japan (I.Y., K.Y., M.C.); and Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan (I.Y., Y.I., H.Y.)
| | - Hideyuki Yamada
- Pharmacokinetics Research Laboratories, Taiho Pharmaceutical Co., Ltd., Tsukuba, Japan (I.Y., K.Y., M.C.); and Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan (I.Y., Y.I., H.Y.)
| | - Masato Chiba
- Pharmacokinetics Research Laboratories, Taiho Pharmaceutical Co., Ltd., Tsukuba, Japan (I.Y., K.Y., M.C.); and Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan (I.Y., Y.I., H.Y.)
| |
Collapse
|
10
|
Fujita KI, Sasaki Y. Optimization of cancer chemotherapy on the basis of pharmacokinetics and pharmacodynamics: from patients enrolled in clinical trials to those in the 'real world'. Drug Metab Pharmacokinet 2013; 29:20-8. [PMID: 24256625 DOI: 10.2133/dmpk.dmpk-13-rv-103] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytotoxic anticancer drugs are the most challenging therapeutic agents among all medicines with relatively narrow efficacy profiles. Therefore, medical oncologists have to practically manage the risk of severe toxic effects to optimize treatment outcomes. Dose and treatment-schedule recommendations for cytotoxic anticancer agents are determined on the basis of clinical trials. Patients enrolled in clinical trials are those likely to receive the drug in clinical practice, excluding those with conditions such as organ dysfunction, obesity, advanced age, or comorbidity. On the other hand, the 'real world' includes large numbers of such patients who do not meet the eligibility criteria of clinical trials. However, there is a paucity of data from sufficiently powered pharmacokinetic and pharmacodynamic studies to support dosage recommendations in such patients. Consequently, dose levels and treatment schedules for chemotherapy in these subjects are somewhat arbitrary and not evidence-based. Pharmacokinetic and pharmacodynamic studies of patients in the 'real world' are needed to address this issue. In this review article, we describe general aspects of clinical pharmacology in cancer patients enrolled in clinical trials and those in the 'real world,' and introduce recent findings regarding the pharmacokinetic and pharmacodynamic properties of irinotecan and S-1 in 'real world' cancer patients.
Collapse
|
11
|
Alessandrini M, Asfaha S, Dodgen TM, Warnich L, Pepper MS. Cytochrome P450 pharmacogenetics in African populations. Drug Metab Rev 2013; 45:253-75. [PMID: 23590174 DOI: 10.3109/03602532.2013.783062] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The Cytochrome P450 (CYP450) family of enzymes is involved in the oxidative metabolism of many therapeutic drugs, carcinogens and various endogenous substrates. These enzymes are highly polymorphic at an inter-individual and inter-ethnic level. Polymorphisms or genetic variations account for up to 30% of inter-individual differences seen in a variety of drug responses. The frequencies of the different metabolizer categories (slow, intermediate, extensive and ultra-rapid), the distribution of genetic variants, genotype-phenotype correlations and the clinical importance of the CYP450 enzymes have been extensively documented in Caucasian and Oriental populations. Limited data exists for African populations, despite the fact that this knowledge is critically important for these populations who experience a heavy burden of communicable and non-communicable diseases. In addition, the costs incurred through adverse drug reactions and non-responsiveness to therapy could be reduced through the wide-scale application of pharmacogenetics. This review provides an overview and investigation of CYP450 genotypic and phenotypic reports published from 1980 to present in African populations. Our findings confirm the high degree of variability that is expected when comparing individuals of African origin to other ethnic groups and also highlight the distribution of clinically relevant CYP450 alleles amongst the various African populations. The notable discordance in genotypic and phenotypic data amongst African populations exemplifies the need for in-depth and well-orchestrated molecular and pharmacological investigations of these populations in the future, for which whole genome sequencing and association studies will be critical.
Collapse
Affiliation(s)
- Marco Alessandrini
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | | | | | | | | |
Collapse
|
12
|
Martis S, Mei H, Vijzelaar R, Edelmann L, Desnick RJ, Scott SA. Multi-ethnic cytochrome-P450 copy number profiling: novel pharmacogenetic alleles and mechanism of copy number variation formation. THE PHARMACOGENOMICS JOURNAL 2012; 13:558-66. [PMID: 23164804 PMCID: PMC3580117 DOI: 10.1038/tpj.2012.48] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 10/09/2012] [Accepted: 10/12/2012] [Indexed: 01/11/2023]
Abstract
To determine the role of CYP450 copy number variation (CNV) beyond CYP2D6, 11 CYP450 genes were interrogated by MLPA and qPCR in 542 African-American, Asian, Caucasian, Hispanic, and Ashkenazi Jewish individuals. The CYP2A6, CYP2B6 and CYP2E1 combined deletion/duplication allele frequencies ranged from 2% to 10% in these populations. High-resolution microarray-based comparative genomic hybridization (aCGH) localized CYP2A6, CYP2B6 and CYP2E1 breakpoints to directly-oriented low-copy repeats. Sequencing localized the CYP2B6 breakpoint to a 529 bp intron 4 region with high homology to CYP2B7P1, resulting in the CYP2B6*29 partial deletion allele and the reciprocal, and novel, CYP2B6/2B7P1 duplicated fusion allele (CYP2B6*30). Together, these data identified novel CYP450 CNV alleles (CYP2B6*30 and CYP2E1*1Cx2) and indicate that common CYP450 CNV formation is likely mediated by non-allelic homologous recombination resulting in both full gene and gene-fusion copy number imbalances. Detection of these CNVs should be considered when interrogating these genes for pharmacogenetic drug selection and dosing.
Collapse
Affiliation(s)
- S Martis
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, NY, USA
| | | | | | | | | | | |
Collapse
|
13
|
Sharma A, Dinesh K, Yadav S, Jain SK, Pant MC, Parmar D. Cytochrome P450 2A isoenzymes in freshly prepared blood lymphocytes isolated from rats and validation as a biomarker for clinical studies in humans. Xenobiotica 2012; 43:311-9. [PMID: 22934830 DOI: 10.3109/00498254.2012.717728] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
1. The present study aimed to identify the expression of carcinogen metabolizing cytochrome P4502A (CYP2A) isoenzymes in freshly prepared rat peripheral blood lymphocytes (PBL) isolated from adult rats and investigate similarities in the regulation of lymphocyte CYP2A-isoenzymes with the tissue enzyme. 2. qRT-PCR studies demonstrated significant constitutive mRNA expression of CYP2A-isoenzymes in PBL isolated from male and female rats which further increases significantly after pretreatment with nicotine or 3-methylcholanthrene (MC) indicating responsiveness of CYP2A-isoenzymes in PBL. This increase in the CYP2A expression was associated with an increase in the protein expression and CYP2A3-dependent coumarin hydroxylase (COH) activity in PBL. 3. Clinical studies further demonstrated significant increase in the expression of CYP2A6 and associated enzyme activity in PBL isolated from lung cancer patients. Our data thus provided evidence for similarities in the regulation of carcinogen metabolizing CYP2A-isoenzymes in PBL with the tissue enzymes. Further, responsiveness of blood CYP2A6 in human blood lymphocytes isolated from lung cancer patients has led us to suggest that associating expression profiles of CYP2A6 and other polycyclic aromatic hydrocarbons (PAH)-responsive CYPs in PBL with the genotyping data could lead to the development of a possible screen to monitor and predict environment-induced diseases and toxicity in humans.
Collapse
Affiliation(s)
- Amit Sharma
- Developmental Toxicology Division, Indian Institute of Toxicology Research (Council of Scientific and Industrial Research), Lucknow, UP, India
| | | | | | | | | | | |
Collapse
|
14
|
Krishnakumar D, Gurusamy U, Dhandapani K, Surendiran A, Baghel R, Kukreti R, Gangadhar R, Prayaga U, Manjunath S, Adithan C. Genetic polymorphisms of drug-metabolizing phase I enzymes CYP2E1, CYP2A6 and CYP3A5 in South Indian population. Fundam Clin Pharmacol 2011; 26:295-306. [PMID: 21265876 DOI: 10.1111/j.1472-8206.2010.00917.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
CYP2E1, CYP2A6 and CYP3A5 enzymes belong to phase I group of drug-metabolizing enzymes, which are involved in the metabolism of various compounds and xenobiotics. Presence of polymorphisms in the genes coding for these enzymes results in interindividual variations in drug metabolism, therapeutic response and susceptibility towards various diseases. The frequencies of these variants in genes differ considerably between ethnic groups. This study was carried out to estimate the allele and genotype frequencies of common variants in CYP2E1, CYP2A6 and CYP3A5 in South Indian population. Six hundred and fifty-two unrelated healthy volunteers of South Indian origin (Andhra Pradesh, Karnataka, Kerala and Tamil Nadu) were included in this study. Polymerase chain reaction-restriction fragment length polymorphism, allele-specific PCR, real-time PCR, SNaPshot and gene sequencing methods were used for the identification of gene polymorphisms. The frequencies of CYP2E1*1B, CYP2E1*5B and CYP2E1*6 alleles in South Indian population were 14.3, 1.3 and 22.4%, respectively. The frequencies of CYP2A6*2, CYP2A6*4A and CYP2A6*5 alleles were found to be 1, 8.9 and 0.7%, respectively. The distribution of CYP3A5*3 allele was 63.5%. There were no variant alleles of CYP3A5*2, CYP3A5*4 and CYP3A5*6 in South Indian population. The frequencies of CYP2E1, CYP2A6 and CYP3A5 in the South Indian population are distinct from Caucasians, Chinese, Japanese, African Americans and other compared populations. This is the first study conducted in the South Indian population with a larger sample size. The findings of our study provide the basic genetic information for further pharmacogenomic investigations in the population.
Collapse
Affiliation(s)
- D Krishnakumar
- ICMR Centre for Advance Research in Pharmacogenomics, Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education & Research, Pondicherry 605 006, India
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Ino T, Ohtani T, Yoshimi I. Urinary biomarkers for secondhand smoke. J Clin Lab Anal 2011; 25:354-8. [PMID: 21919071 PMCID: PMC6647727 DOI: 10.1002/jcla.20485] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Accepted: 07/14/2011] [Indexed: 11/11/2022] Open
Abstract
The use of a biomarker is mandatory for quantitative analysis of exposure to secondhand smoke (SHS). This article summarizes urinary biomarkers of smoke exposure which can be now quantified. The most reliable urinary biomarkers to assess the exposure to SHS are NNAL 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and NNAL-Glucuronides, which is metabolites of tobacco-specific nitrosamine. These substances were detected even in 50% of children who had undetectable level of cotinine (<0.5 ng/ml). Urinary cotinine, which is determined by a highly sensitive competing enzyme immunoassay, is also a useful biomarker. However, individual variability of CYP2A6 allele,in which nicotine is catalyzed to cotinine, affects the level of urinary cotinine. Approximately 20% of Japanese subjects have homozygotes or heterozygotes of the CYP2A6*4 allele, which has impaired nicotine metabolism and subsequently may underestimate the actual exposure to SHS. In assessing the exposure to SHS, therefore, individual variability of CYP2A6 gene polymorphism should be taken into consideration. The combination of urinary cotinine measurement and self-report of parents' smoking seems to be accurate to assess the exposure to SHS in mass screening.
Collapse
Affiliation(s)
- Toshihiro Ino
- Faculty of Health Science, Gunma Paz College, Takasaki, Gunma, Japan.
| | | | | |
Collapse
|
16
|
Can the 2-(13)C-uracil breath test be used to predict the effect of the antitumor drug S-1? Cancer Chemother Pharmacol 2009; 66:333-43. [PMID: 19921195 DOI: 10.1007/s00280-009-1168-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 10/27/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE S-1 is an oral anticancer drug containing tegafur (FT), a pro-drug of fluorouracil, combined with two modulators, 5-chloro-2,4-dihydroxypyridine and potassium oxonate (Oxo), at a molar ratio of 1:0.4:1. CYP2A6 genetic polymorphism and dihydropyrimidine dehydrogenase (DPD) inhibition are important for the antitumor effect of S-1. Exploiting the usefulness of the 2-(13)C-uracil breath test (UrBT) as an indicator of DPD activity, we examined whether the results of CYP2A6 genetic polymorphism analysis and UrBT could be used to predict the antitumor effect of S-1. METHODS Thirty-four patients with advanced or recurrent cancer (15, 16 and 3 with gastric, colorectal and pancreatic cancer, respectively) were orally administered 40 mg/m(2) S-1 twice daily in the morning and evening. Eighteen patients with a complete response (CR)/partial response (PR) (2 with CR, 16 with PR) and 16 with progressive disease (PD) were compared with respect to CYP2A6 genetic polymorphisms (1- vs. 2-allele mutation), UrBT results, and plasma FT and 5-fluorouracil levels at 3 h after S-1 ingestion in the morning. RESULTS On multivariate analysis between the CR/PR and PD groups, only the UrBT results was an independent factor of CR/PR to S-1 (95% CI 1.02-1.10). CONCLUSION These results suggest that the anticancer effect of S-1 can be predicted by performing UrBT 3 h after the initial oral S-1 administration.
Collapse
|
17
|
Zhou SF, Liu JP, Chowbay B. Polymorphism of human cytochrome P450 enzymes and its clinical impact. Drug Metab Rev 2009; 41:89-295. [PMID: 19514967 DOI: 10.1080/03602530902843483] [Citation(s) in RCA: 502] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pharmacogenetics is the study of how interindividual variations in the DNA sequence of specific genes affect drug response. This article highlights current pharmacogenetic knowledge on important human drug-metabolizing cytochrome P450s (CYPs) to understand the large interindividual variability in drug clearance and responses in clinical practice. The human CYP superfamily contains 57 functional genes and 58 pseudogenes, with members of the 1, 2, and 3 families playing an important role in the metabolism of therapeutic drugs, other xenobiotics, and some endogenous compounds. Polymorphisms in the CYP family may have had the most impact on the fate of therapeutic drugs. CYP2D6, 2C19, and 2C9 polymorphisms account for the most frequent variations in phase I metabolism of drugs, since almost 80% of drugs in use today are metabolized by these enzymes. Approximately 5-14% of Caucasians, 0-5% Africans, and 0-1% of Asians lack CYP2D6 activity, and these individuals are known as poor metabolizers. CYP2C9 is another clinically significant enzyme that demonstrates multiple genetic variants with a potentially functional impact on the efficacy and adverse effects of drugs that are mainly eliminated by this enzyme. Studies into the CYP2C9 polymorphism have highlighted the importance of the CYP2C9*2 and *3 alleles. Extensive polymorphism also occurs in other CYP genes, such as CYP1A1, 2A6, 2A13, 2C8, 3A4, and 3A5. Since several of these CYPs (e.g., CYP1A1 and 1A2) play a role in the bioactivation of many procarcinogens, polymorphisms of these enzymes may contribute to the variable susceptibility to carcinogenesis. The distribution of the common variant alleles of CYP genes varies among different ethnic populations. Pharmacogenetics has the potential to achieve optimal quality use of medicines, and to improve the efficacy and safety of both prospective and currently available drugs. Further studies are warranted to explore the gene-dose, gene-concentration, and gene-response relationships for these important drug-metabolizing CYPs.
Collapse
Affiliation(s)
- Shu-Feng Zhou
- School of Health Sciences, RMIT University, Bundoora, Victoria, Australia.
| | | | | |
Collapse
|
18
|
Canova C, Hashibe M, Simonato L, Nelis M, Metspalu A, Lagiou P, Trichopoulos D, Ahrens W, Pigeot I, Merletti F, Richiardi L, Talamini R, Barzan L, Macfarlane GJ, Macfarlane TV, Holcátová I, Bencko V, Benhamou S, Bouchardy C, Kjaerheim K, Lowry R, Agudo A, Castellsagué X, Conway DI, McKinney PA, Znaor A, McCartan BE, Healy CM, Marron M, Brennan P. Genetic associations of 115 polymorphisms with cancers of the upper aerodigestive tract across 10 European countries: the ARCAGE project. Cancer Res 2009; 69:2956-65. [PMID: 19339270 DOI: 10.1158/0008-5472.can-08-2604] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cancers of the upper aerodigestive tract (UADT) include malignant tumors of the oral cavity, pharynx, larynx, and esophagus and account for 6.4% of all new cancers in Europe. In the context of a multicenter case-control study conducted in 14 centers within 10 European countries and comprising 1,511 cases and 1,457 controls (ARCAGE study), 115 single nucleotide polymorphisms (SNP) from 62 a priori-selected genes were studied in relation to UADT cancer. We found 11 SNPs that were statistically associated with UADT cancers overall (5.75 expected). Considering the possibility of false-positive results, we focused on SNPs in CYP2A6, MDM2, tumor necrosis factor (TNF), and gene amplified in squamous cell carcinoma 1 (GASC1), for which low P values for trend (P trend<0.01) were observed in the main effects analyses of UADT cancer overall or by subsite. The rare variant of CYP2A6 -47A>C (rs28399433), a phase I metabolism gene, was associated with reduced UADT cancer risk (P trend=0.01). Three SNPs in the MDM2 gene, involved in cell cycle control, were associated with UADT cancer. MDM2 IVS5+1285A>G (rs3730536) showed a strong codominant effect (P trend=0.007). The rare variants of two SNPs in the TNF gene were associated with a decreased risk; for TNF IVS1+123G>A (rs1800610), the P trend was 0.007. Variants in two SNPs of GASC1 were found to be strongly associated with increased UADT cancer risk (for both, P trend=0.008). This study is the largest genetic epidemiologic study on UADT cancers in Europe. Our analysis points to potentially relevant genes in various pathways.
Collapse
Affiliation(s)
- Cristina Canova
- Department of Environmental Medicine and Public Health, University of Padova, Padova, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Yusof W, Gan SH. High prevalence of CYP2A6⁎4 and CYP2A6⁎9 alleles detected among a Malaysian population. Clin Chim Acta 2009; 403:105-9. [DOI: 10.1016/j.cca.2009.01.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 01/28/2009] [Accepted: 01/28/2009] [Indexed: 10/21/2022]
|
20
|
Veiga MI, Asimus S, Ferreira PE, Martins JP, Cavaco I, Ribeiro V, Hai TN, Petzold MG, Björkman A, Ashton M, Gil JP. Pharmacogenomics of CYP2A6, CYP2B6, CYP2C19, CYP2D6, CYP3A4, CYP3A5 and MDR1 in Vietnam. Eur J Clin Pharmacol 2008; 65:355-63. [DOI: 10.1007/s00228-008-0573-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 09/21/2008] [Indexed: 11/28/2022]
|
21
|
Abstract
Lung cancer is the leading cause of cancer-related death and thus a major health problem. The efficiency of current treatment modalities for lung cancer depends strongly on the time of diagnosis, with better chances of survival if a tumor has been detected at an early stage. Thus, there is an urgent need for rapid and efficient early detection methods. Biomarkers represent a possible alternative to current, rather expensive, screening tools such as spiral computer tomography (CT), or may allow the identification of high risk groups for whom screening would be cost efficient. Although most lung cancers are the consequence of smoking, a substantial fraction of molecular-epidemiological studies point to high-prevalence, low-penetrance genetic polymorphisms as modifiers of environmental lung cancer risk. In the past the genomics field has also made significant advances in identifying genetic lesions that can now be harvested with the goal of identifying novel biomarkers for lung cancer. Furthermore, the importance of epigenetic changes that occur during lung cancer development has been reported, but has been underestimated in the past. Novel high-throughput, quantitative assays for the detection of DNA methylation or histone tail modifications are now applied, to search for alterations in the lung cancer genome and will identify novel cancer-related genes that may become attractive targets for treatment, provide new insight into the biology of lung cancers, and could also become useful biomarkers for the early detection of lung cancer in sputum, or may be used as prognostic markers. Thus, an integrative approach in lung cancer research combining epidemiological, genetic and epigenetic information becomes an important concept for the future.
Collapse
Affiliation(s)
- Angela Risch
- German Cancer Research Center, Division of Epigenomics and Cancer Risk Factors, Heidelberg, Germany
| | | |
Collapse
|
22
|
Fujita KI, Yamamoto W, Endo S, Endo H, Nagashima F, Ichikawa W, Tanaka R, Miya T, Araki K, Kodama K, Sunakawa Y, Narabayashi M, Miwa K, Ando Y, Akiyama Y, Kawara K, Kamataki T, Sasaki Y. CYP2A6 and the plasma level of 5-chloro-2, 4-dihydroxypyridine are determinants of the pharmacokinetic variability of tegafur and 5-fluorouracil, respectively, in Japanese patients with cancer given S-1. Cancer Sci 2008; 99:1049-54. [PMID: 18380793 PMCID: PMC11158323 DOI: 10.1111/j.1349-7006.2008.00773.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
S-1 is an oral anticancer agent composed of tegafur (FT), 5-chloro-2,4-dihydroxypyridine (CDHP), and potassium oxonate. CDHP is added to prevent degradation of 5-fluorouracil (5-FU) by inhibiting dihydropyrimidine dehydrogenase. CYP2A6 is involved in the biotransformation of FT to 5-FU. Thus, we prospectively analyzed the effects of the CYP2A6 genotype, plasma level of CDHP, and patient characteristics on the pharmacokinetic (PK) variability of FT and 5-FU. Fifty-four Japanese patients with metastatic or recurrent cancers who received S-1 were enrolled. The CYP2A6 polymorphisms (*4A, *7, and *9) with deficient or reduced activity were analyzed. All subjects were classified into three groups according to their CYP2A6 genotype: wild type (*1/*1), one-variant allele (*1/any), or two-variant alleles (combination other than *1). The PK of FT, 5-FU, and CDHP were measured on day 1 of treatment. Multivariate regression analysis revealed that oral clearance of FT was associated with the CYP2A6 genotype (analysis of variance [ANOVA], P = 0.000838). The oral clearance of FT seen in patients with the two-variant alleles was significantly lower than those in wild type and the one-variant allele (95% confidence intervals 0.75-2.41 and 0.41-1.82, respectively; Tukey-Kramer test). The area under the time-concentration curve (AUC) of 5-FU was significantly correlated with the AUC of CDHP (ANOVA, P = 0.00126). The AUC of 5-FU and CDHP were inversely correlated with creatinine clearance (ANOVA, P = 0.0164 and P = 0.000762, respectively). Although the CYP2A6 variants are the cause of the PK variability of FT, the AUC of CDHP affected by renal function is the key determinant of the variability in the PK of 5-FU.
Collapse
Affiliation(s)
- Ken-ichi Fujita
- Department of Medical Oncology, Comprehensive Cancer Center, Saitama Medical University, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Mwenifumbo JC, Tyndale RF. Genetic variability in CYP2A6 and the pharmacokinetics of nicotine. Pharmacogenomics 2007; 8:1385-402. [DOI: 10.2217/14622416.8.10.1385] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nicotine is the psychoactive substance responsible for tobacco dependence. It is also a therapeutic used to aid smoking cessation. Cytochrome P450 (CYP)2A6 is the human hepatic enzyme that mediates most of nicotine’s metabolic inactivation to cotinine. Genetic variation in the CYP2A6 gene can increase or decrease enzyme activity through altering the protein’s expression level or its structure and function. This article reviews CYP2A6 genetic variation and its impact on in vivo nicotine kinetics, including a description of the individual variants, different phenotyping approaches for assessing in vivo CYP2A6 activity and other sources of variation in nicotine metabolism such as gender. In addition, the effect of CYP2A6 polymorphisms on smoking behavior and tobacco-related lung cancer risk are briefly described. Furthering knowledge in this area will improve interpretation of studies examining smoking behavior, as well as those using nicotine as a therapeutic agent.
Collapse
Affiliation(s)
- Jill C Mwenifumbo
- University of Toronto, Rm 4326 Medical Sciences Building, 1 King’s College Circle, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Rachel F Tyndale
- University of Toronto, Rm 4326 Medical Sciences Building, 1 King’s College Circle, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| |
Collapse
|
24
|
Gresner P, Gromadzinska J, Wasowicz W. Polymorphism of selected enzymes involved in detoxification and biotransformation in relation to lung cancer. Lung Cancer 2007; 57:1-25. [PMID: 17337085 DOI: 10.1016/j.lungcan.2007.02.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 01/30/2007] [Accepted: 02/04/2007] [Indexed: 01/22/2023]
Abstract
Available data indicate that there are significant differences in individual susceptibility to lung cancer within the human population. It is believed to be underlie by inherited genetic predispositions related to the genetic polymorphism of several enzymes involved in the detoxification and xenobiotic metabolism. In this review, we collect and discuss the evidence reported up to date on the association between lung cancer and genetic polymorphism of cytochromes P450, N-acetyltransferase, glutathione S-transferases, microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, myeloperoxidase and glutathione peroxidase. All these genes might appear to be candidates for lung cancer susceptibility genes, nevertheless, the present state of the art still offers only a limited explanation of the link between such polymorphisms and increased risk of lung cancer.
Collapse
Affiliation(s)
- Peter Gresner
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Lodz, Poland.
| | | | | |
Collapse
|
25
|
Farinola N, Piller NB. CYP2A6 polymorphisms: is there a role for pharmacogenomics in preventing coumarin-induced hepatotoxicity in lymphedema patients? Pharmacogenomics 2007; 8:151-8. [PMID: 17286538 DOI: 10.2217/14622416.8.2.151] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Lymphedema is a chronic progressive and significantly disabling disease that affects over 150 million people worldwide. Coumarin is an effective pharmacological treatment, but is banned in some countries due to incidences of hepatotoxicity in rats and mice, and the rare finding of similar hepatotoxicity in humans. Cytochrome P450 (CYP)2A6 is the major enzyme involved in metabolizing coumarin to 7-hydroxycoumarin. A reduction in CYP2A6 activity will lead to shunting of coumarin into other metabolic pathways. In particular, coumarin is metabolized by CYP3A4 to form 3-hydroxycoumarin, the major metabolite in mice and rats. It has been shown that an increase in the 3-hydroxycoumarin ratio is associated with an increased production of the significant cytotoxic product o-hydroxyphenylacetylacetaldehyde (o-HPA), suggesting that a shunting of coumarin metabolism away from 7-hydroxylation is the cause of the toxicity. Hence, poor CYP2A6 metabolizers are more likely to metabolize coumarin via the cytotoxic pathway. Identifying these patients, and not treating them with coumarin, may reduce the incidence of toxicity associated with this drug. The technology to do so exists, but more information is required regarding the mechanism of coumarin toxicity.
Collapse
Affiliation(s)
- Nicholas Farinola
- Lymphedema Assessment Clinic, Department of Surgery, School of Medicine, Flinders University and Flinders Medical Centre, Bedford Park, South Australia, 5042, Australia
| | | |
Collapse
|
26
|
Fukami T, Nakajima M, Yamanaka H, Fukushima Y, McLeod HL, Yokoi T. A novel duplication type of CYP2A6 gene in African-American population. Drug Metab Dispos 2007; 35:515-20. [PMID: 17267622 DOI: 10.1124/dmd.106.013557] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human CYP2A6 is responsible for the metabolism of nicotine and its genetic polymorphisms affect smoking behavior and risk of lung cancer. In the present study, we identified a novel type of CYP2A6 gene duplication that is created through an unequal crossover event with the CYP2A7 gene at 5.2 to 5.6 kilobases downstream from the stop codon. The novel duplication type of CYP2A6 was found in African Americans (n = 176) at an allele frequency of 1.7%, but was not found in European-American (n = 187), Korean (n = 209), or Japanese (n = 184) populations. The plasma cotinine/nicotine ratio in subjects possessing the novel CYP2A6 gene duplication with the CYP2A6*1 allele (10.8 +/- 7.0, n = 4) was 1.4-fold higher than that in homozygotes of the wild type (8.0 +/- 5.0, n = 87), although the difference was not statistically significant. The findings in the present study suggested that the novel duplicated CYP2A6 allele, which is specific for African Americans, would increase nicotine metabolism and may affect smoking behavior.
Collapse
Affiliation(s)
- Tatsuki Fukami
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | | | | | | | | | | |
Collapse
|
27
|
Fukami T, Nakajima M, Sakai H, McLeod HL, Yokoi T. CYP2A7 polymorphic alleles confound the genotyping of CYP2A6*4A allele. THE PHARMACOGENOMICS JOURNAL 2006; 6:401-12. [PMID: 16636685 DOI: 10.1038/sj.tpj.6500390] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 02/17/2006] [Accepted: 02/24/2006] [Indexed: 11/09/2022]
Abstract
Human cytochrome P450 (CYP) 2A6 metabolizes nicotine to cotinine. Genetic polymorphisms of CYP2A6 contribute to the interindividual variability of nicotine metabolism. We encountered some subjects possessing two copies of the CYP2A6 gene, although they were genotyped as heterozygotes of the CYP2A6*4A allele (entire CYP2A6 gene deleted allele). From the subjects, we found CYP2A7 polymorphic alleles (CYP2A7*1B, CYP2A7*1C, and CYP2A7*1D) in which the sequences in the 3'-flanking region were converted to the corresponding CYP2A6 sequences, being confused with the CYP2A6*4A. These allele frequencies in European-Americans (n=187) were 1.3, 2.1, 0.3%, respectively, but these were very rare in African-Americans (n=176), Japanese (n=184), and Koreans (n=209). By an improved genotyping method, the allele frequency of CYP2A6*4A of 3.7% in European-Americans was corrected to 0%. The comprehensible and reliable genotyping method developed in this study would be useful to evaluate associations between the genotype and phenotype.
Collapse
Affiliation(s)
- T Fukami
- Department of Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa, Japan
| | | | | | | | | |
Collapse
|
28
|
Nakajima M, Itoh M, Yamanaka H, Fukami T, Tokudome S, Yamamoto Y, Yamamoto H, Yokoi T. Isoflavones inhibit nicotine C-oxidation catalyzed by human CYP2A6. J Clin Pharmacol 2006; 46:337-44. [PMID: 16490810 DOI: 10.1177/0091270005285199] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The inhibitory effects of isoflavones (daidzein, genistein, and glycitein) on human cytochrome P450 (CYP) 2A6 activities were investigated. Daidzein, genistein, and glycitein uncompetitively inhibited nicotine C-oxidation catalyzed by recombinant CYP2A6 expressed in baculovirus-infected insect cells with Ki values of 1.3 +/- 0.3 microM, 0.7 +/- 0.2 microM, and 5.2 +/- 0.8 microM, respectively, but not coumarin 7-hydroxylation. Effects of the intake of soy isoflavones on in vivo nicotine metabolism were investigated with 7 healthy Japanese homozygotes of CYP2A6*1. The cotinine/nicotine ratio of the plasma concentrations 2 hours after chewing 1 piece of nicotine gum under the basal condition (after abstaining from soy foods for 1 week) was 8.8 +/- 2.6 (4.4-11.4). The ratio was significantly (P < .05) reduced to 6.7 +/- 1.6 (4.0-8.2) after consumption of a soy isoflavone supplement (60 mg of total isoflavones/d) for 5 days. The authors found that isoflavone contained in soy products significantly decreased nicotine metabolism.
Collapse
Affiliation(s)
- Miki Nakajima
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Haberl M, Anwald B, Klein K, Weil R, Fuss C, Gepdiremen A, Zanger UM, Meyer UA, Wojnowski L. Three haplotypes associated with CYP2A6 phenotypes in Caucasians. Pharmacogenet Genomics 2005; 15:609-24. [PMID: 16041240 DOI: 10.1097/01.fpc.0000171517.22258.f1] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The human cytochrome P450 2A6 (CYP2A6) enzyme metabolizes several xenobiotic compounds of clinical or toxicological importance. We aimed to identify genetic variants and major CYP2A6 haplotypes associated with CYP2A6 phenotypic variation. CYP2A6 mRNA level, protein level, activity and haplotypes were determined in Caucasian liver samples via real-time polymerase chain reaction, Western blot, coumarin 7-hydroxylation, DNA sequencing and genotyping, respectively. Phenotypes were then analyzed for associations with haplotypes. CYP2A6 transcript, protein and activity levels were correlated among each other. In 45 African-American, 156 Caucasian, 47 Chinese, 50 Japanese and 47 Korean DNA samples, we detected 95 different polymorphisms in the CYP2A6 gene, 49 of which had not been described previously. Caucasian variants formed 33 haplotypes which built four clades. Allele *9B and the CYP2A7/2A6 partial deletion allele CYP2A6*12B were both associated with decreased expression. The latter haplotype extends at least over 147 kb up into the CYP2B6 gene. A haplotype almost identical to allele *1A was associated with decreased expression and activity of CYP2A6 compared to all other haplotypes. In summary A CYP2A6*1A-like allele, *9B and *12B are major genetic determinants of CYP2A6 phenotype variation in Caucasians.
Collapse
|
30
|
Fukami T, Nakajima M, Higashi E, Yamanaka H, McLeod HL, Yokoi T. A novel CYP2A6*20 allele found in African-American population produces a truncated protein lacking enzymatic activity. Biochem Pharmacol 2005; 70:801-8. [PMID: 15993850 DOI: 10.1016/j.bcp.2005.05.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 05/14/2005] [Accepted: 05/23/2005] [Indexed: 10/25/2022]
Abstract
Human CYP2A6 is a cytochrome P450 (CYP) isoform responsible for the metabolism of nicotine, coumarin, tegafur, and valproic acid, and metabolic activation of nitrosamines. Genetic polymorphisms of the CYP2A6 gene are a major causal factor of the large interindividual differences in nicotine metabolism. In the present study, we identified a novel allele, termed CYP2A6*20, in an African-American population. The allele possesses the deletion of two nucleotides in exon 4 resulting in a frame-shift from codon 196 and an early stop codon at 220 (exon 5) as well as three synonymous SNPs of G51A (G51A in cDNA), T5684C (T1191C), and C6692G (C1546G, 3'-untranslated region). The allele frequency in the African-American population (n=96) was 1.6% (95% confidence interval, 0.6-4.5%). In contrast, the CYP2A6*20 allele was not found in Caucasians (European-American) (n=185), Japanese (n=184) and Korean (n=209) populations. To investigate the effects of the polymorphism on the enzymatic activities, we expressed a wild type or variant (deletion of two nucleotides) CYP2A6 together with NADPH-CYP reductase in Escherichia coli. SDS-PAGE and immunoblot analyses demonstrated that truncated CYP2A6 protein was produced from the variant allele, although detected mRNA was the predicted size by reverse transcriptional-polymerase chain reaction. Coumarin 7-hydroxylation and nicotine C-oxidation, which are typical CYP2A6 activities, were completely abolished in the E. coli membrane expressing the variant allele. In vivo nicotine metabolism was evaluated using the cotinine/nicotine ratio 2 h after the chewing of one piece of nicotine gum. Two CYP2A6*1/CYP2A6*20 heterozygotes and a single CYP2A6*17/CYP2A6*20 heterozygote revealed lower cotinine/nicotine ratios compared with CYP2A6*1/CYP2A6*1 subjects (1.6 and 4.5, and 1.8 versus 9.5+/-5.4, n=52, respectively). We found a novel CYP2A6*20 allele in African-American subjects which codes a truncated protein lacking enzymatic activity.
Collapse
Affiliation(s)
- Tatsuki Fukami
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | | | | | | | | | | |
Collapse
|
31
|
Fukami T, Nakajima M, Higashi E, Yamanaka H, Sakai H, McLeod HL, Yokoi T. CHARACTERIZATION OF NOVELCYP2A6POLYMORPHIC ALLELES (CYP2A6*18ANDCYP2A6*19) THAT AFFECT ENZYMATIC ACTIVITY. Drug Metab Dispos 2005; 33:1202-10. [PMID: 15900015 DOI: 10.1124/dmd.105.004994] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Genetic polymorphisms of CYP2A6 gene are known as a causal factor of the interindividual differences in nicotine metabolism. We found three novel CYP2A6 alleles. The CYP2A6(*)18A allele has a single nucleotide polymorphism (SNP) of A5668T (A1175T, Y392F) in exon 8. The CYP2A6(*)18B allele has synonymous SNPs of G51A (G51A), T5684C (T1191C), and T5702C (T1209C) in addition to A5668T (A1175T, Y392F). The CYP2A6(*)19 allele has the SNPs of A5668T (A1175T, Y392F), T6354C (intron 8), and T6558C (T1412C, I471T) as well as the conversion with the CYP2A7 sequence in the 3'-untranslated region, in which the latter two changes correspond to CYP2A6(*)7. Ethnic differences in the frequencies of these alleles were observed between whites, African-Americans, Japanese, and Koreans. Wild or variant CYP2A6 (CYP2A6(*)18, CYP2A6(*)19, and CYP2A6(*)7) were expressed in Escherichia coli. For coumarin 7-hydroxylation and 5-fluorouracil formation from tegafur, the K(m) values were increased, and V(max) values were decreased in CYP2A6.18 compared with those in CYP2A6.1, resulting in decreased clearance to 50 and 35% of that of the wild type, respectively. The K(m) and V(max) values for nicotine C-oxidation were both increased, resulting in no change of clearance. In CYP2A6.19, the effects on the coumarin 7-hydroxylation and 5-fluorouracil formation (increased K(m) and decreased V(max)) were prominent, resulting in decreased clearance to 8% of those of the wild type. For nicotine C-oxidation, the K(m) and V(max) values were both decreased, resulting in decreased clearance to 30% of that of the wild type. The changes of the kinetics in CYP2A6.19 were similar to those in CYP2A6.7. In vivo nicotine metabolism was evaluated in whites (n = 56) and Koreans (n = 40). Although the CYP2A6(*)18 and CYP2A6(*)19 alleles were found only heterozygously, a subject with CYP2A6(*)7/CYP2A6(*)19 showed a lower cotinine/nicotine ratio of the plasma concentration compared with homozygotes of the CYP2A6(*)1A, supporting the in vitro results that the CYP2A6(*)19 allele leads to decreased enzymatic activity.
Collapse
Affiliation(s)
- Tatsuki Fukami
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | | | | | | | | | | | | |
Collapse
|
32
|
Yamanaka H, Nakajima M, Nishimura K, Yoshida R, Fukami T, Katoh M, Yokoi T. Metabolic profile of nicotine in subjects whose CYP2A6 gene is deleted. Eur J Pharm Sci 2005; 22:419-25. [PMID: 15265511 DOI: 10.1016/j.ejps.2004.04.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 04/15/2004] [Accepted: 04/22/2004] [Indexed: 11/25/2022]
Abstract
Generally, 70-80% of absorbed nicotine is mainly metabolized to cotinine by cytochrome P450 (CYP) 2A6. There is genetic polymorphism in the human CYP2A6 gene. Among several mutated alleles, CYP2A6*4 allele is a whole deleted type. The purpose of the present study was to clarify the metabolic profile of nicotine in subjects whose CYP2A6 gene is deleted. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for nicotine and its nine metabolites. Excretion levels of nicotine and its metabolites in 24 h accumulated urine after the chewing of one piece of nicotine gum were evaluated in five Japanese subjects whose CYP2A6 genotype was determined. In three subjects with CYP2A6*1A/CYP2A6*1A, CYP2A6*1A/CYP2A6*1B, and CYP2A6*1A/CYP2A6*4 (group I), nicotine was mainly excreted as cotinine, trans-3'-hydroxycotinine, and their glucuronide (approximately 60%). In contrast, in two subjects with CYP2A6*4/CYP2A6*4 (group II), trace levels of cotinine, cotinine N-glucuronide, and cotinine 1'-N-oxide were detected. Trans-3'-hydroxycotinine and its O-glucuronide were not detected. The excretion levels of nicotine itself, nicotine N-glucuronide, and nicotine 1'-N-oxide were higher than those in the other three subjects. The total excretion levels of these three compounds were approximately 95% in group II versus 35% in group I. However, the sum of the excretion levels of nicotine and all metabolites was similar among these five subjects. This is the first report of the metabolic profile of nicotine in subjects whose CYP2A6 gene is deleted.
Collapse
Affiliation(s)
- Hiroyuki Yamanaka
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | | | | | | | | | | | | |
Collapse
|
33
|
Gyamfi MA, Fujieda M, Kiyotani K, Yamazaki H, Kamataki T. High prevalence of cytochrome P450 2A6*1A alleles in a black African population of Ghana. Eur J Clin Pharmacol 2005; 60:855-7. [PMID: 15660270 DOI: 10.1007/s00228-004-0854-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2004] [Accepted: 09/27/2004] [Indexed: 11/24/2022]
Abstract
OBJECTIVE We investigated the frequencies of the functionally important variants of the CYP2A6 gene in black African populations. METHODS Using genomic DNA sequencing, polymerase chain reaction (PCR)-restriction fragment length polymorphism and allele-specific PCR, the allele frequencies of CYP2A6 *1A, *1B, *2, *4A, *5, *6, *7, *8, *9, *10 and * 11 among 120 black Africans- including 105 Ghanaians, 12 Nigerians, 2 Ivorians and 1 Ugandan-were determined. RESULTS The allele frequencies were 80.5% for CYP2A6*1A, 11.9% for CYP2A6*1B, 1.9% for CYP2A6*4A and 5.7% for CYP2A6*9 in the Ghanaian subjects. No subject homozygous for the CYP2A6*4A allele, a whole gene deletion type of polymorphism prevalent among Orientals, was found. Furthermore, CYP2A6 variants such as *2, *5, *6, *7, *8, *10 and *11 were absent in these black African populations. CONCLUSIONS This study provides, for the first time, the results of the analysis of CYP2A6 allele frequency in black African populations and confirms large ethnic differences in the polymorphic CYP2A6 gene.
Collapse
Affiliation(s)
- Maxwell Afari Gyamfi
- Laboratory of Drug Metabolism, Graduate School of Pharmaceutical Sciences, Hokkaido University, N12W6, Kita-ku, Sapporo 060-0812, Japan
| | | | | | | | | |
Collapse
|
34
|
Vasconcelos GM, Struchiner CJ, Suarez-Kurtz G. CYP2A6 genetic polymorphisms and correlation with smoking status in Brazilians. THE PHARMACOGENOMICS JOURNAL 2004; 5:42-8. [PMID: 15534625 DOI: 10.1038/sj.tpj.6500290] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We investigated polymorphisms of cytochrome P450 2A6 (CYP2A6) and its association with smoking habits in 412 healthy Brazilians, self-recognized as white (n=147), black (n=123) and intermediate (n=142), and classified as smokers (n=205, including 61 ex-smokers) and nonsmokers (n=207). The frequencies of the variant alleles CYP2A6(*)1B, CYP2A6(*)2, CYP2A6(*)4 and CYP2A6(*)9 in the overall study population were 29.9, 1.7, 0.5 and 5.7%, respectively. Significant differences in the CYP2A6 allelic distribution were observed across the three population subgroups. There was a statistically significant trend for decreasing frequency of CYP2A6(*)1B from white to intermediate and to black persons. An association between CYP2A6 genotype and smoking dependence was detected, which could not be explained by the expected phenotypic activity of CYP2A6. In white and intermediate persons, the odds ratio (OR) of being smokers vs nonsmokers was 0.07 (95% CI 0.02-0.20; P<0.001) and 0.27 (95% CI 0.12-0.61; P<0.001), respectively, for genotypes including allele CYP2A6(*)1B, as compared to wild-type homozygous. In contrast, the corresponding OR in black Brazilians was 1.34 (95% CI 0.57-3.17; P=0.46). These data suggest that the CYP2A6(*)1B is associated with smoking dependence in white and intermediate, but not black Brazilians.
Collapse
Affiliation(s)
- G M Vasconcelos
- Divisão de Farmacologia, Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, RJ, Brazil
| | | | | |
Collapse
|
35
|
Katoh M, Matsui T, Nakajima M, Tateno C, Kataoka M, Soeno Y, Horie T, Iwasaki K, Yoshizato K, Yokoi T. EXPRESSION OF HUMAN CYTOCHROMES P450 IN CHIMERIC MICE WITH HUMANIZED LIVER. Drug Metab Dispos 2004; 32:1402-10. [PMID: 15383493 DOI: 10.1124/dmd.104.001347] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, a chimeric mouse line in which the liver could be replaced by more than 80% with human hepatocytes was established in Japan. Because the chimeric mouse produces human albumin (hAlb), replacement by human hepatocytes could be estimated by the hAlb concentration in the blood of chimeric mice. In this study, we investigated human major cytochrome P450 (P450) in the livers of chimeric mice by mRNA, protein, and enzyme activity using real-time polymerase chain reaction, Western blot analysis, and high-performance liquid chromatography, respectively. Chimeric mice with humanized liver generated using hepatocytes from a Japanese and white donor were used. Human P450 mRNAs were expressed in the liver of chimeric mice, and major human P450 proteins such as CYP1A2, CYP2C9, and CYP3A4 were detected. The expression of P450 mRNA and protein was correlated with the hAlb concentration in the blood. The enzyme activities such as diclofenac 4'-hydroxylase activity, dexamethasone 6-hydroxylase activity, and coumarin 7-hydroxylase activity, activities that are specific to human P450 but not to murine P450, were increased in a hAlb concentration-dependent manner. The chimeric mice with nearly 90% replacement by human hepatocytes demonstrated almost the same protein contents of human P450s and drug-metabolizing enzyme activity as those of the donor. It was confirmed that genomic DNA from the livers of the chimeric mice and that from the liver of the donor exhibited the same genotype. In conclusion, the chimeric mice exhibited a similarly efficient capacity of drug metabolism as humans, suggesting that they could be a useful animal model for drug development.
Collapse
Affiliation(s)
- Miki Katoh
- Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|