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Abuelsoud NN, El Khateeb EM. Genetic polymorphisms effect on cyclophosphamide's tolerability and clinical efficacy in Egyptian patients with lupus nephritis. Pharmacogenet Genomics 2023; 33:172-180. [PMID: 37611146 DOI: 10.1097/fpc.0000000000000506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
OBJECTIVES Many studies were conducted to determine the association between genetic polymorphisms in CYP2B6 c.516G>T and cyclophosphamide (CYC) efficacy or toxicity, no studies were focused on both clinical efficacy and toxicity of CYC. This study aimed to investigate the relationship between the CYP2B6 c.516G>T polymorphism (rs 3745274) and 17 different parameters related to CYC efficacy and tolerability in Egyptian patients with lupus nephritis (LN). METHODS A prospective cohort study on 142 LN patients with a mean age of 36.26 was conducted at Kasr Al Ainy School of Medicine, Cairo University, Egypt after the exclusion of 14 patients due to receiving an interacting medication with CYC. All clinical parameters related to CYC efficacy or toxicity were recorded and compared between the different genotypes. RESULTS There was a statistically significant difference between different genotypes in 11 out of 13 of the studied efficacy-related parameters. Many of the studied clinical parameters revealed that CYC's efficacy was associated with the presence of the T allele. There was a statistically significant difference between different genotypes in hepatotoxicity, diarrhea, and blood-related toxicities. CONCLUSION To our knowledge, this study is the first study that focused on studying 17 different parameters related to CYC efficacy and tolerability. Our findings paint a picture of the function that CYP2B6 polymorphisms play in Egyptian LN patients. Pre-treatment evaluation of CYP2B6 rs 3745274 may account for some individual differences in treatment response.
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Affiliation(s)
- Nermeen N Abuelsoud
- Department of Pharmacy Practice and Clinical Pharmacy, College of Pharmacy, Egyptian Russian University
| | - Engy M El Khateeb
- Department of Clinical and Chemical Pathology, Kasr Al Aini School of Medicine, Cairo University, Egypt
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2
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Angle ED, Cox PM. Multidisciplinary Insights into the Structure-Function Relationship of the CYP2B6 Active Site. Drug Metab Dispos 2023; 51:369-384. [PMID: 36418184 DOI: 10.1124/dmd.122.000853] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 10/12/2022] [Accepted: 11/04/2022] [Indexed: 11/27/2022] Open
Abstract
Cytochrome P450 2B6 (CYP2B6) is a highly polymorphic human enzyme involved in the metabolism of many clinically relevant drugs, environmental toxins, and endogenous molecules with disparate structures. Over the last 20-plus years, in silico and in vitro studies of CYP2B6 using various ligands have provided foundational information regarding the substrate specificity and structure-function relationship of this enzyme. Approaches such as homology modeling, X-ray crystallography, molecular docking, and kinetic activity assays coupled with CYP2B6 mutagenesis have done much to characterize this originally neglected monooxygenase. However, a complete understanding of the structural details that make new chemical entities substrates of CYP2B6 is still lacking. Surprisingly little in vitro data has been obtained about the structure-function relationship of amino acids identified to be in the CYP2B6 active site. Since much attention has already been devoted to elucidating the function of CYP2B6 allelic variants, here we review the salient findings of in silico and in vitro studies of the CYP2B6 structure-function relationship with a deliberate focus on the active site. In addition to summarizing these complementary approaches to studying structure-function relationships, we note gaps/challenges in existing data such as the need for more CYP2B6 crystal structures, molecular docking results with various ligands, and data coupling CYP2B6 active site mutagenesis with kinetic parameter measurement under standard expression conditions. Harnessing in silico and in vitro techniques in tandem to understand the CYP2B6 structure-function relationship will likely offer further insights into CYP2B6-mediated metabolism. SIGNIFICANCE STATEMENT: The apparent importance of cytochrome P450 2B6 (CYP2B6) in the metabolism of various xenobiotics and endogenous molecules has grown since its discovery with many in silico and in vitro studies offering a partial description of its structure-function relationship. Determining the structure-function relationship of CYP2B6 is difficult but may be aided by thorough biochemical investigations of the CYP2B6 active site that provide a more complete pharmacological understanding of this important enzyme.
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Affiliation(s)
- Ethan D Angle
- Department of Biology and Chemistry, College of Liberal Arts and Sciences, Azusa Pacific University, Azusa, California (E.D.A., P.M.C.) and Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa (E.D.A.)
| | - Philip M Cox
- Department of Biology and Chemistry, College of Liberal Arts and Sciences, Azusa Pacific University, Azusa, California (E.D.A., P.M.C.) and Roy J. and Lucille A. Carver College of Medicine University of Iowa, Iowa City, Iowa (E.D.A.)
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3
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Frequency of CYP2B6 Alleles in Major Iranian Ethnicities, Affecting Response to Efavirenz. Genet Res (Camb) 2022; 2022:5754776. [PMID: 36320932 PMCID: PMC9605844 DOI: 10.1155/2022/5754776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/29/2022] [Accepted: 10/03/2022] [Indexed: 11/17/2022] Open
Abstract
Introduction Efavirenz is an antihuman immunodeficiency virus (HIV) drug metabolized by cytochrome P450 2B6 (CYP2B6) enzyme. Cytochrome P450 2B6 is an enzyme that in humans is encoded by the CYP2B6 gene. Polymorphisms of this gene play a crucial role in the metabolism of drugs such as Efavirenz. This study aims to evaluate the frequency of three clinically significant CYP2B6 polymorphisms (CYP2B6∗6 (516G > T), CYP2B6∗4 (785A > G), and CYP2B6∗5 (1459C > T)) in three major Iranian ethnicities. Methods One hundred forty-seven participants from three main Iranian ethnicities were included in this study. After DNA extraction, CYP2B6∗6 (516G > T), CYP2B6∗4 (785A > G), and CYP2B6∗5 (1459C > T) were genotyped using tetra-primer amplification refractory mutation system polymerase chain reaction (ARMS-PCR). Results The frequency of the mutated allele in the Iranian population for CYP2B6∗6 (516G > T) was 41.50 (95% CI: 35.81, 47.36), which was significantly lower than in Kurds (59.62, 95% CI: 45.10, 72.99). Similarly, Kurds had a higher frequency of mutated allele of CYP2B6∗5 (1459C > T) (46.15%, 95% CI: 32.23, 60.53) than in Iranians (24.49%, 95% CI: 19.68, 29.82). The frequency of A and G alleles of CYP2B6∗4 (785A > G) was 62.59% (95% CI: 56.78, 68.13) and 37.41 (95% CI: 31.87, 43.22), respectively. Conclusion Kurds are at higher risk of adverse drug reactions (ADRs) and insufficient anti-HIV response compared to other Iranians.
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Shi M, Dong Y, Bouwmeester H, Rietjens IMCM, Strikwold M. In vitro-in silico-based prediction of inter-individual and inter-ethnic variations in the dose-dependent cardiotoxicity of R- and S-methadone in humans. Arch Toxicol 2022; 96:2361-2380. [PMID: 35604418 PMCID: PMC9217890 DOI: 10.1007/s00204-022-03309-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 04/27/2022] [Indexed: 12/02/2022]
Abstract
New approach methodologies predicting human cardiotoxicity are of interest to support or even replace in vivo-based drug safety testing. The present study presents an in vitro–in silico approach to predict the effect of inter-individual and inter-ethnic kinetic variations in the cardiotoxicity of R- and S-methadone in the Caucasian and the Chinese population. In vitro cardiotoxicity data, and metabolic data obtained from two approaches, using either individual human liver microsomes or recombinant cytochrome P450 enzymes (rCYPs), were integrated with physiologically based kinetic (PBK) models and Monte Carlo simulations to predict inter-individual and inter-ethnic variations in methadone-induced cardiotoxicity. Chemical specific adjustment factors were defined and used to derive dose–response curves for the sensitive individuals. Our simulations indicated that Chinese are more sensitive towards methadone-induced cardiotoxicity with Margin of Safety values being generally two-fold lower than those for Caucasians for both methadone enantiomers. Individual PBK models using microsomes and PBK models using rCYPs combined with Monte Carlo simulations predicted similar inter-individual and inter-ethnic variations in methadone-induced cardiotoxicity. The present study illustrates how inter-individual and inter-ethnic variations in cardiotoxicity can be predicted by combining in vitro toxicity and metabolic data, PBK modelling and Monte Carlo simulations. The novel methodology can be used to enhance cardiac safety evaluations and risk assessment of chemicals.
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Affiliation(s)
- Miaoying Shi
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands. .,NHC Key Laboratory of Food Safety Risk Assessment, Chinese Academy of Medical Sciences Research Unit (No. 2019RU014), China National Center for Food Safety Risk Assessment, Beijing, 100021, China.
| | - Yumeng Dong
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Hans Bouwmeester
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Marije Strikwold
- Van Hall Larenstein University of Applied Sciences, 8901 BV, Leeuwarden, The Netherlands
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5
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Nakano M, Iwakami C, Fukami T, Nakajima M. Identification of miRNAs that regulate human CYP2B6 expression. Drug Metab Pharmacokinet 2021; 38:100388. [PMID: 33872945 DOI: 10.1016/j.dmpk.2021.100388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/20/2021] [Accepted: 02/23/2021] [Indexed: 01/11/2023]
Abstract
Human hepatic cytochrome P450 2B6 (CYP2B6) expressed is responsible for the metabolism of many drugs, such as cyclophosphamide, ifosfamid, and efavirenz. In the present study, the correlation between CYP2B6 mRNA and protein levels in human liver samples was found to be moderate, indicating a contribution of posttranscriptional regulation of CYP2B6. Thus, we examined the role of microRNAs (miRNAs) in the regulation of CYP2B6. We established two kinds of HEK293 cell lines stably expressing CYP2B6, including or excluding the full-length 3'-untranslated region (3'-UTR) (HEK/2B6+UTR and HEK/2B6 cells, respectively). We tested 14 miRNAs that were predicted to bind to the 3'-UTR of CYP2B6 and found that the overexpression of miR-145, miR-194, miR-222, and miR-378 decreased the CYP2B6 protein level and activity in HEK/2B6+UTR but not in HEK/2B6 cells. These results suggested that miR-145, miR-194, miR-222, and miR-378 negatively regulate CYP2B6 expression by binding to the 3'-UTR. A negative correlation was not observed between the translational efficiency of CYP2B6 and the expression level of miR-145, miR-194, miR-222, or miR-378. This is due to the contribution of multiple miRNAs to CYP2B6 regulation. In conclusion, this study demonstrated that human CYP2B6 is posttranscriptionally regulated by miR-145, miR-194, miR-222, and miR-378.
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Affiliation(s)
- Masataka Nakano
- Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan; WPI Nano Life Science Institute (WPI-NanoLSI) Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Chika Iwakami
- Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Tatsuki Fukami
- Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan; WPI Nano Life Science Institute (WPI-NanoLSI) Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Miki Nakajima
- Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan; WPI Nano Life Science Institute (WPI-NanoLSI) Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.
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6
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Butryn DM, Chi LH, Gross MS, McGarrigle B, Schecter A, Olson JR, Aga DS. Retention of polybrominated diphenyl ethers and hydroxylated metabolites in paired human serum and milk in relation to CYP2B6 genotype. JOURNAL OF HAZARDOUS MATERIALS 2020; 386:121904. [PMID: 31901712 DOI: 10.1016/j.jhazmat.2019.121904] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/30/2019] [Accepted: 12/14/2019] [Indexed: 05/06/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) and their hydroxylated metabolites (OH-BDEs) are endocrine disrupting compounds prevalent in human serum and breast milk. Retention of PBDEs and OH-BDEs in humans may be affected by differences in PBDE metabolism due to variants in cytochrome P450 2B6 (CYP2B6). The objectives of this study are to assess the partitioning profiles of PBDEs and OH-BDEs in forty-eight paired human serum and milk samples, and to evaluate the relationship between variants in CYP2B6 genotype and PBDE and OH-BDE accumulation in humans. Results show that the geometric mean (GM) concentrations of PBDEs are similar in serum (GM = 43.4 ng/g lipid) and milk samples (GM = 52.9 ng/g lipid), while OH-BDEs are retained primarily in serum (GM = 2.31 ng/g lipid), compared to milk (GM = 0.045 ng/g lipid). Participants with CYP2B6*6 genotype had a greater relative retention of PBDEs in serum and milk, and significant relationships (p < 0.05) were also observed for PBDE-47, 5-OH-BDE-47 and 6-OH-BDE-47 concentrations relative to CYP2B6*5 and CYP2B6*6 genotypes. These results are the first to show that CYP2B6 genotype is significantly related to the relative retention of PBDEs in humans, which may have direct implications for variability in the susceptibility of individuals to the potential adverse effects of these contaminants.
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Affiliation(s)
- Deena M Butryn
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, 611 Natural Sciences Complex, Buffalo, NY, 14260, USA
| | - Lai-Har Chi
- Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York. 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA; Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA
| | - Michael S Gross
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, 611 Natural Sciences Complex, Buffalo, NY, 14260, USA
| | - Barbara McGarrigle
- Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York. 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA; Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA
| | - Arnold Schecter
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, 323 East Chesnut Street, Louisville, KY, 40202, USA; University of Louisville School of Public Health and Information Sciences, 485 E Gray St. Louisville, KY, 40202, USA
| | - James R Olson
- Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York. 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA; Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA
| | - Diana S Aga
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, 611 Natural Sciences Complex, Buffalo, NY, 14260, USA.
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Zhao S, Kamelia L, Boonpawa R, Wesseling S, Spenkelink B, Rietjens IMCM. Physiologically based kinetic modelling-facilitated reverse dosimetry to predict in vivo red blood cell acetylcholinesterase inhibition following exposure to chlorpyrifos in the Caucasian and Chinese population. Toxicol Sci 2019; 171:69-83. [PMID: 31214721 PMCID: PMC6736452 DOI: 10.1093/toxsci/kfz134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/26/2019] [Accepted: 05/23/2019] [Indexed: 11/25/2022] Open
Abstract
Organophosphates have a long history of use as insecticides over the world. The aim of the present study was to investigate the interethnic differences in kinetics, biomarker formation, and in vivo red blood cell acetylcholinesterase inhibition of chlorpyrifos (CPF) in the Chinese and the Caucasian population. To this purpose, physiologically based kinetic models for CPF in both the Chinese and Caucasian population were developed, and used to study time- and dose-dependent interethnic variation in urinary biomarkers and to convert concentration-response curves for red blood cell acetylcholinesterase inhibition to in vivo dose-response curves in these 2 populations by reverse dosimetry. The results obtained revealed a marked interethnic difference in toxicokinetics of CPF, with lower urinary biomarker levels at similar dose levels and slower CPF bioactivation and faster chlorpyrifos-oxon detoxification in the Chinese compared with the Caucasian population, resulting in 5- to 6-fold higher CPF sensitivity of the Caucasian than the Chinese population. These differences might be related to variation in the frequency of single-nucleotide polymorphisms for the major biotransformation enzymes involved. To conclude, the interethnic variation in kinetics of CPF may affect both its biomarker-based exposure assessment and its toxicity and risk assessment and physiologically based kinetic modeling facilitates the characterization and quantification of these interethnic variations.
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Affiliation(s)
- Shensheng Zhao
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
| | - Lenny Kamelia
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
| | - Rungnapa Boonpawa
- Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Thailand
| | - Sebastiaan Wesseling
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
| | - Bert Spenkelink
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
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8
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Lam YWF. Principles of Pharmacogenomics. Pharmacogenomics 2019. [DOI: 10.1016/b978-0-12-812626-4.00001-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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9
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Ferrari M, Tozzi M, Marino F, Tarallo A, Riva F, Mirabile M, Castelli P, Cosentino M. Clopidogrel pharmacogenetics: associations between genotype and stent thrombosis risk in patients with stent placement. J Cardiovasc Med (Hagerstown) 2018; 20:46-48. [PMID: 30531616 DOI: 10.2459/jcm.0000000000000738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | - Matteo Tozzi
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | | | - Antonio Tarallo
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Francesca Riva
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | | | - Patrizio Castelli
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
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Lu N, Meng F, Xu W, Tang L, Xu Y. Molecular simulation study of CYP2B6 polymorphism with and without psoralen. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1513646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Nan Lu
- School of Pharmaceutical Engineering, and Key Laboratory of Structure-Based Drug Design & Discovery, Shenyang Pharmaceutical University, Shenyang, People’s Republic of China
| | - Fancui Meng
- Tianjin Key Laboratory of Molecular Design and Drug Discovery, Tianjin Institute of Pharmaceutical Research, Tianjin, People’s Republic of China
| | - Weiren Xu
- Tianjin Key Laboratory of Molecular Design and Drug Discovery, Tianjin Institute of Pharmaceutical Research, Tianjin, People’s Republic of China
| | - Lida Tang
- Tianjin Key Laboratory of Molecular Design and Drug Discovery, Tianjin Institute of Pharmaceutical Research, Tianjin, People’s Republic of China
| | - Youjun Xu
- School of Pharmaceutical Engineering, and Key Laboratory of Structure-Based Drug Design & Discovery, Shenyang Pharmaceutical University, Shenyang, People’s Republic of China
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11
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Watanabe T, Saito T, Rico EMG, Hishinuma E, Kumondai M, Maekawa M, Oda A, Saigusa D, Saito S, Yasuda J, Nagasaki M, Minegishi N, Yamamoto M, Yamaguchi H, Mano N, Hirasawa N, Hiratsuka M. Functional characterization of 40 CYP2B6 allelic variants by assessing efavirenz 8-hydroxylation. Biochem Pharmacol 2018; 156:420-430. [PMID: 30201214 DOI: 10.1016/j.bcp.2018.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/06/2018] [Indexed: 12/20/2022]
Abstract
Genetic variations within cytochrome P450 2B6 (CYP2B6) contribute to inter-individual variation in the metabolism of clinically important drugs, including cyclophosphamide, bupropion, methadone and efavirenz (EFZ). In this study, we performed an in vitro analysis of 40 CYP2B6 allelic variant proteins including seven novel variants identified in 1070 Japanese individuals. Wild-type and 39 variant proteins were heterologously expressed in 293FT cells to estimate the kinetic parameters (Km, Vmax, and CLint) of EFZ 8-hydroxylation and 7-ethoxy-4-trifluoromethylcoumarin (7-ETC) O-deethylation activities. The concentrations of CYP2B6 variant holo-enzymes were measured by using carbon monoxide (CO)-reduced difference spectroscopy, and the wild-type and 28 variants showed a peak at 450 nm. The kinetic parameters were measured for the wild-type and 24 variant proteins. The values for the remaining 15 variants could not be determined because the enzymatic activity was not detected at the highest substrate concentration used. Compared to wild-type, six variants showed significantly decreased EFZ 8-hydroxylation CLint values, while these values were significantly increased in another six variants, including CYP2B6.6. Although 7-ETC O-deethylation CLint values of CYP2B6 variants did not differ significantly from that of CYP2B6.1, the CLint ratios obtained for 7-ETC O-deethylation were highly correlated with EFZ 8-hydroxylation. Furthermore, three-dimensional structural modeling analysis was performed to elucidate the mechanism of changes in the kinetics of CYP2B6 variants. Our findings could provide evidence of the specific metabolic activities of the CYP2B6 proteins encoded by these variant alleles.
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Affiliation(s)
- Takashi Watanabe
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; Department of Pharmacy, Tohoku Rosai Hospital, Sendai 981-8563, Japan
| | - Takahiro Saito
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Evelyn Marie Gutiérrez Rico
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Eiji Hishinuma
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, Sendai 980-8575, Japan; Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8575, Japan
| | - Masaki Kumondai
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Masamitsu Maekawa
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai 980-8574, Japan
| | - Akifumi Oda
- Faculty of Pharmacy, Meijo University, Nagoya 468-8503, Japan
| | - Daisuke Saigusa
- Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8575, Japan
| | - Sakae Saito
- Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8575, Japan
| | - Jun Yasuda
- Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8575, Japan
| | - Masao Nagasaki
- Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8575, Japan
| | - Naoko Minegishi
- Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8575, Japan
| | - Masayuki Yamamoto
- Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, Sendai 980-8575, Japan; Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8575, Japan
| | - Hiroaki Yamaguchi
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai 980-8574, Japan
| | - Nariyasu Mano
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai 980-8574, Japan
| | - Noriyasu Hirasawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, Sendai 980-8575, Japan; Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai 980-8574, Japan
| | - Masahiro Hiratsuka
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan; Advanced Research Center for Innovations in Next-Generation Medicine, Tohoku University, Sendai 980-8575, Japan; Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8575, Japan; Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai 980-8574, Japan.
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12
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Ma H, Zhang W, Yang X, Zhang Y, Wei S, Zhang H, Ma Y, Dang H. Effects of Genetic Polymorphisms of CYP2B6 on the Pharmacokinetics of Bupropion and Hydroxybupropion in Healthy Chinese Subjects. Med Sci Monit 2018; 24:2158-2163. [PMID: 29637923 PMCID: PMC5914277 DOI: 10.12659/msm.909227] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 03/22/2018] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Bupropion (BUP) is an antidepressant and its pharmacological activity is mediated by its major metabolite, hydroxybupropion (HBUP). We investigated the effects of genetic polymorphisms of CYP2B6 on BUP and HBUP to provide certain evidence on the clinical rational administration of BUP. MATERIAL AND METHODS Plasma BUP and HBUP concentrations were assayed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). RESULTS A total of 23 healthy volunteers (eleven participants with CYP2B6*1/*1, 7 participants with CYP2B6*1/*6, 3 participants with CYP2B6*4/*6, and 2 participants with CYP2B6*1/*4) received orally administered 150 mg of BUP according to protocol. Blood samples were obtained up to 96 hours after administration. The whole blood was subject to genotyping by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). The concentration-time curve (AUC(0→96)), maximum plasma concentration (Cmax), and terminal half-life (t1/2) values of BUP in CYP2B6*1/*4 were lower than those of CYP2B6*1/*1. By contrast, the time to Cmax (tmax) value of the former was higher than that of the latter. The HBUP AUC(0→96) values in CYP2B6*4/*6 and CYP2B6*1/*4 increased to values 1.12-fold and 1.98-fold, compared with CYP2B6*1/*1 carriers. However, the HBUP AUC(0→96) value in CYP2B6*1/*1 was 1.51-fold higher than that in CYP2B6*1/*6. Similarly, the HBUP Cmax values in CYP2B6*4/*6 and CYP2B6*1/*4 increased by 1.12-fold and 1.97-fold, whereas the HBUP Cmax value in CYP2B6*1/*6 decreased to a value 1.64-fold lower than that in CYP2B6*1/*1. CONCLUSIONS Genetic polymorphisms of CYP2B6 influence the pharmacokinetic parameters of BUP and HBUP and thus establish rational BUP administration for Chinese patients in clinical settings.
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Affiliation(s)
- Hui Ma
- College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
| | - Wenping Zhang
- Institute of Clinical Pharmacology and Department of Pharmacy, General Hospital of Ningxia Medical University, and College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
| | - Xiaoying Yang
- Institute of Clinical Pharmacology and Department of Pharmacy, General Hospital of Ningxia Medical University, and College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
| | - Yuxin Zhang
- Institute of Clinical Pharmacology and Department of Pharmacy, General Hospital of Ningxia Medical University, and College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
| | - Shijie Wei
- Institute of Clinical Pharmacology and Department of Pharmacy, General Hospital of Ningxia Medical University, and College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
| | - Hao Zhang
- Institute of Clinical Pharmacology and Department of Pharmacy, General Hospital of Ningxia Medical University, and College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
| | - Yanni Ma
- Institute of Clinical Pharmacology and Department of Pharmacy, General Hospital of Ningxia Medical University, and College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
| | - Hongwan Dang
- Institute of Clinical Pharmacology and Department of Pharmacy, General Hospital of Ningxia Medical University, and College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
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13
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Imaishi H, Goto T. Effect of genetic polymorphism of human CYP2B6 on the metabolic activation of chlorpyrifos. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2018; 144:42-48. [PMID: 29463407 DOI: 10.1016/j.pestbp.2017.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/05/2017] [Accepted: 11/09/2017] [Indexed: 06/08/2023]
Abstract
Chlorpyrifos (CPS) is a broad-spectrum organophosphate insecticide that is neurotoxic in humans. Chlorpyrifos oxon (CPO) is a toxic metabolite of CPS that is produced by CYP2B6. In this study, we examined the variability of CPS metabolism resulting from single-nucleotide polymorphisms in CYP2B6. Wild-type CYP2B6 (CYP2B6.1) and two variants each with a single amino acid substitution: CYP2B6.5 (R487C) and CYP2B6.8 (K139E) were co-expressed together with human NADPH-dependent cytochrome P450 reductase in Escherichia coli (E. coli). Both of the CYP2B6 variants were successfully expressed in E. coli. The conversion of CPS to CPO by the CYP2B6 variants was analyzed with high-performance liquid chromatography. Km and Vmax of the reaction by CYP2B6.1 were 18.50±2.94μM and 17.07±1.15mol/min/mol P450, respectively. The CYP2B6 variants produced CPO with the following kinetic parameters: Km for CYP2B6.5 and CYP2B6.8 were 20.44±6.43 and 44.69±9.97μM, respectively; and Vmax were 1.10±0.10 and 1.77±0.26mol/min/mol P450, respectively. These results indicate that the amino acid substitutions in the CYP2B6 variants suppressed the metabolic activation of CPS. CYP2B6 variants have altered capacity to bioactivate CPF and may affect individual susceptibility of CPF.
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Affiliation(s)
- Hiromasa Imaishi
- Laboratory of Response to Environmental Materials, Division of Signal Responses, Biosignal Research Center, Kobe University, Nada-ku, Kobe, Hyogo 657-8501, Japan.
| | - Tatsushi Goto
- Laboratory of Response to Environmental Materials, Division of Signal Responses, Biosignal Research Center, Kobe University, Nada-ku, Kobe, Hyogo 657-8501, Japan
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14
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Carr DF, Bourgeois S, Chaponda M, Takeshita LY, Morris AP, Castro EMC, Alfirevic A, Jones AR, Rigden DJ, Haldenby S, Khoo S, Lalloo DG, Heyderman RS, Dandara C, Kampira E, van Oosterhout JJ, Ssali F, Munderi P, Novelli G, Borgiani P, Nelson MR, Holden A, Deloukas P, Pirmohamed M. Genome-wide association study of nevirapine hypersensitivity in a sub-Saharan African HIV-infected population. J Antimicrob Chemother 2017; 72:1152-1162. [PMID: 28062682 PMCID: PMC5400091 DOI: 10.1093/jac/dkw545] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/20/2016] [Indexed: 01/11/2023] Open
Abstract
Background The antiretroviral nevirapine is associated with hypersensitivity reactions in 6%-10% of patients, including hepatotoxicity, maculopapular exanthema, Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Objectives To undertake a genome-wide association study (GWAS) to identify genetic predisposing factors for the different clinical phenotypes associated with nevirapine hypersensitivity. Methods A GWAS was undertaken in a discovery cohort of 151 nevirapine-hypersensitive and 182 tolerant, HIV-infected Malawian adults. Replication of signals was determined in a cohort of 116 cases and 68 controls obtained from Malawi, Uganda and Mozambique. Interaction with ERAP genes was determined in patients positive for HLA-C*04:01 . In silico docking studies were also performed for HLA-C*04:01 . Results Fifteen SNPs demonstrated nominal significance ( P < 1 × 10 -5 ) with one or more of the hypersensitivity phenotypes. The most promising signal was seen in SJS/TEN, where rs5010528 ( HLA-C locus) approached genome-wide significance ( P < 8.5 × 10 -8 ) and was below HLA -wide significance ( P < 2.5 × 10 -4 ) in the meta-analysis of discovery and replication cohorts [OR 4.84 (95% CI 2.71-8.61)]. rs5010528 is a strong proxy for HLA-C*04:01 carriage: in silico docking showed that two residues (33 and 123) in the B pocket were the most likely nevirapine interactors. There was no interaction between HLA-C*04:01 and ERAP1 , but there is a potential protective effect with ERAP2 [ P = 0.019, OR 0.43 (95% CI 0.21-0.87)]. Conclusions HLA-C*04:01 predisposes to nevirapine-induced SJS/TEN in sub-Saharan Africans, but not to other hypersensitivity phenotypes. This is likely to be mediated via binding to the B pocket of the HLA-C peptide. Whether this risk is modulated by ERAP2 variants requires further study.
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Affiliation(s)
- Daniel F Carr
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Stephane Bourgeois
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Mas Chaponda
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK.,Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Louise Y Takeshita
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Andrew P Morris
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK.,Department of Biostatistics, University of Liverpool, Liverpool, UK
| | - Elena M Cornejo Castro
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Ana Alfirevic
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Andrew R Jones
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Daniel J Rigden
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Sam Haldenby
- Centre for Genomic Research, University of Liverpool, Liverpool, UK
| | - Saye Khoo
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | | | - Robert S Heyderman
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi.,Division of Infection and Immunity, University College London, London, UK
| | - Collet Dandara
- Division of Human Genetics, University of Cape Town, Cape Town, South Africa
| | - Elizabeth Kampira
- Division of Human Genetics, University of Cape Town, Cape Town, South Africa
| | - Joep J van Oosterhout
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi.,Dignitas International, Zomba, Malawi
| | - Francis Ssali
- Joint Clinical Research Centre, Headquarters, Kampala, Uganda
| | - Paula Munderi
- UVRI/MRC Uganda Research Unit on AIDS, Entebbe, Uganda
| | - Giuseppe Novelli
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Paola Borgiani
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | | | | | - Panos Deloukas
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.,Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.,Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders (PACER-HD), King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Munir Pirmohamed
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
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15
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Bahramsoltani R, Rahimi R, Farzaei MH. Pharmacokinetic interactions of curcuminoids with conventional drugs: A review. JOURNAL OF ETHNOPHARMACOLOGY 2017; 209:1-12. [PMID: 28734960 DOI: 10.1016/j.jep.2017.07.022] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 07/14/2017] [Accepted: 07/15/2017] [Indexed: 06/07/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Herb-drug interactions are of great concern in health practices. Curcumin is a natural polyphenol extracted from turmeric, a spice widely used all over the world. Curcumin is clinically used due to its acceptable safety profile and therapeutic efficacy. AIM OF THE STUDY Current paper aims to highlight the effect of curcumin on concomitantly used drugs. METHODS Electronic databases including PubMed, Scopus and Science Direct were searched with the keywords "curcumin" in the title/abstract and "drug interaction," "drug metabolism," "cytochrome," "P-glycoprotein" and "P450" in the whole text. RESULTS Curcumin can induce pharmacokinetic alterations such as changes in Cmax and AUC when concomitantly used with pharmacological agents like cardiovascular drugs, antidepressants, anticoagulants, antibiotics, chemotherapeutic agents, and antihistamines. The underlying mechanisms of these interactions include inhibition of cytochrome (CYP) isoenzymes and P-glycoprotein. There is only one clinical trial which proved a significant alteration of conventional drugs in concomitant use with curcumin indicating the need for further human studies. CONCLUSIONS Although in vitro and in vivo studies do not provide enough evidence to judge the clinical drug interactions of curcumin, physicians must remain cautious and avoid drug combinations which may lead to curcumin-drug interactions.
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Affiliation(s)
- Roodabeh Bahramsoltani
- Department of Traditional Pharmacy, School of Traditional Medicine, Tehran University of Medical Sciences, Tehran 1417614411, Iran; PhytoPharmacology Interest Group (PPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
| | - Roja Rahimi
- Department of Traditional Pharmacy, School of Traditional Medicine, Tehran University of Medical Sciences, Tehran 1417614411, Iran; PhytoPharmacology Interest Group (PPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
| | - Mohammad Hosein Farzaei
- Pharmaceutical Sciences Research Center, Kermanshah University of Medical Sciences, Kermanshah 6734667149, Iran; Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah 6734667149, Iran.
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16
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Genistein: Its role in metabolic diseases and cancer. Crit Rev Oncol Hematol 2017; 119:13-22. [PMID: 29065980 DOI: 10.1016/j.critrevonc.2017.09.004] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/23/2017] [Accepted: 09/11/2017] [Indexed: 12/12/2022] Open
Abstract
Genistein is an isoflavone present in soy and is known to have multiple molecular effects, such as the inhibition of inflammation, promotion of apoptosis, and modulation of steroidal hormone receptors and metabolic pathways. Since these molecular effects impact carcinogenesis, cancer propagation, obesity, osteoporosis, and metabolic syndromes, genistein plays an important role in preventing and treating common disorders. The role of genistein has not been adequately evaluated in all these clinical settings. This review summarizes some of the known molecular effects of genistein and its potential role in health maintenance and treatment.
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17
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Rufini S, Ciccacci C, Politi C, Giardina E, Novelli G, Borgiani P. Stevens-Johnson syndrome and toxic epidermal necrolysis: an update on pharmacogenetics studies in drug-induced severe skin reaction. Pharmacogenomics 2015; 16:1989-2002. [PMID: 26555663 DOI: 10.2217/pgs.15.128] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Stevens-Johnson syndrome and toxic epidermal necrolysis are severe, life-threatening drug reactions involving skin and membranes mucous, which are associated with significant morbidity and mortality and triggered, especially by drug exposure. Different studies have demonstrated that drug response is a multifactorial character and that the interindividual variability in this response depends on both environmental and genetic factors. The last ones have a relevant significance. In fact, the identification of new specific genetic markers involved in the response to drugs, will be of great utility to establish a more personalized therapeutic approach and to prevent the appearance of these adverse reactions. In this review, we summarize recent progresses in the Pharmacogenetics studies related to Stevens-Johnson syndrome/toxic epidermal necrolysis reporting the major genetic factors identified in the last years as associated with the disease and highlighting the use of some of these genomic variants in the clinical practice.
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Affiliation(s)
- Sara Rufini
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Italy
| | - Cinzia Ciccacci
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Italy
| | - Cristina Politi
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Italy
| | - Emiliano Giardina
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Italy.,Laboratory of Molecular Genetics UILDM, Fondazione Santa Lucia, Rome, Italy
| | - Giuseppe Novelli
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Italy
| | - Paola Borgiani
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Italy
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18
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Beyerle J, Frei E, Stiborova M, Habermann N, Ulrich CM. Biotransformation of xenobiotics in the human colon and rectum and its association with colorectal cancer. Drug Metab Rev 2015; 47:199-221. [PMID: 25686853 DOI: 10.3109/03602532.2014.996649] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In humans, the liver is generally considered to be the major organ contributing to drug metabolism, but studies during the last years have suggested an important role of the extra-hepatic drug metabolism. The gastrointestinal tract (GI-tract) is the major path of entry for a wide variety of compounds including food, and orally administered drugs, but also compounds - with neither nutrient nor other functional value - such as carcinogens. These compounds are metabolized by a large number of enzymes, including the cytochrome P450 (CYP), the glutathione S-transferase (GST) family, the uridine 5'-diphospho- glucuronosyltransferase (UDP-glucuronosyltransferase - UGT) superfamily, alcohol-metabolizing enzymes, sulfotransferases, etc. These enzymes can either inactivate carcinogens or, in some cases, generate reactive species with higher reactivity compared to the original compound. Most data in this field of research originate from animal or in vitro studies, wherein human studies are limited. Here, we review the human studies, in particular the studies on the phenotypic expression of these enzymes in the colon and rectum to get an impression of the actual enzyme levels in this primary organ of exposure. The aim of this review is to give a summary of currently available data on the relation between the CYP, the GST and the UGT biotransformation system and colorectal cancer obtained from clinical and epidemiological studies in humans.
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Affiliation(s)
- Jolantha Beyerle
- Division of Preventive Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT) , Heidelberg , Germany
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19
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Effects of CYP2B6 genetic polymorphisms in patients receiving cyclophosphamide combination chemotherapy for breast cancer. Cancer Chemother Pharmacol 2014; 75:207-14. [DOI: 10.1007/s00280-014-2632-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 11/14/2014] [Indexed: 01/22/2023]
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20
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Carr DF, Chaponda M, Cornejo Castro EM, Jorgensen AL, Khoo S, Van Oosterhout JJ, Dandara C, Kampira E, Ssali F, Munderi P, Lalloo DG, Heyderman RS, Pirmohamed M. CYP2B6 c.983T>C polymorphism is associated with nevirapine hypersensitivity in Malawian and Ugandan HIV populations. J Antimicrob Chemother 2014; 69:3329-34. [PMID: 25147095 PMCID: PMC4228781 DOI: 10.1093/jac/dku315] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background Nevirapine, an NNRTI used in HIV treatment, can cause hypersensitivity reactions in 6%–10% of patients. In the most serious cases (1.3%) this can manifest as Stevens–Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN). Methods DNA samples were obtained and analysed from a total of 209 adult patients with nevirapine hypersensitivity (57 from a prospective cohort and 152 routine clinic patients) and compared with 463 control patients on nevirapine without any hypersensitivity. The case group included 70 patients with SJS/TEN. All individuals were genotyped for two SNPs in the CYP2B6 gene [c.516G>T (CYP2B6*9) and c.983T>C (CYP2B6*18)] using the TaqMan real-time genotyping platform. The replication cohort comprised 29 controls and 55 nevirapine hypersensitive patients, including 8 SJS/TEN cases. Results An association between the CYP2B6 c.983T>C polymorphism and nevirapine-induced SJS/TEN was observed. In the SJS/TEN group, 30% of individuals possessed at least one c.983T>C versus 16% in the tolerant group [P = 0.006; OR (95% CI) 2.24 (1.27–3.94)]. This association was not significant in the replication cohort [P = 0.075; OR (95% CI) 4.33 (0.80–23.57)]. Combined analysis resulted in an OR of 2.52 (95% CI 1.48–4.20; P = 0.0005) for the association of c.983T>C with SJS/TEN. No association was observed for c.983T>C with other hypersensitivity phenotypes and for CYP2B6 c.516G>T with any hypersensitivity phenotypes. Conclusions Our data show an association between the c.983T>C polymorphism and nevirapine-induced SJS/TEN. CYP2B6 c.983T>C has a frequency of 5%–10% in a variety of African populations, but is not observed in Caucasians, thus representing an ethnic-specific predisposing factor.
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Affiliation(s)
- Daniel F Carr
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Mas Chaponda
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Elena M Cornejo Castro
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | | | - Saye Khoo
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Joep J Van Oosterhout
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi Dignitas International, Zomba, Malawi
| | - Collet Dandara
- Division of Human Genetics, University of Cape Town, Cape Town, South Africa
| | - Elizabeth Kampira
- Division of Human Genetics, University of Cape Town, Cape Town, South Africa Department of Pathology, College of Medicine, Blantyre, Malawi
| | | | - Paula Munderi
- UVRI/MRC Uganda Research Unit on AIDS, Entebbe, Uganda
| | | | - Robert S Heyderman
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi Liverpool School of Tropical Medicine, Liverpool, UK
| | - Munir Pirmohamed
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
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21
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Court MH, Almutairi FE, Greenblatt DJ, Hazarika S, Sheng H, Klein K, Zanger UM, Bourgea J, Patten CJ, Kwara A. Isoniazid mediates the CYP2B6*6 genotype-dependent interaction between efavirenz and antituberculosis drug therapy through mechanism-based inactivation of CYP2A6. Antimicrob Agents Chemother 2014; 58:4145-52. [PMID: 24820076 PMCID: PMC4068589 DOI: 10.1128/aac.02532-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 05/04/2014] [Indexed: 01/11/2023] Open
Abstract
Efavirenz is commonly used to treat patients coinfected with human immunodeficiency virus and tuberculosis. Previous clinical studies have observed paradoxically elevated efavirenz plasma concentrations in patients with the CYP2B6*6/*6 genotype (but not the CYP2B6*1/*1 genotype) during coadministration with the commonly used four-drug antituberculosis therapy. This study sought to elucidate the mechanism underlying this genotype-dependent drug-drug interaction. In vitro studies were conducted to determine whether one or more of the antituberculosis drugs (rifampin, isoniazid, pyrazinamide, or ethambutol) potently inhibit efavirenz 8-hydroxylation by CYP2B6 or efavirenz 7-hydroxylation by CYP2A6, the main mechanisms of efavirenz clearance. Time- and concentration-dependent kinetics of inhibition by the antituberculosis drugs were determined using genotyped human liver microsomes (HLMs) and recombinant CYP2A6, CYP2B6.1, and CYP2B6.6 enzymes. Although none of the antituberculosis drugs evaluated at up to 10 times clinical plasma concentrations were found to inhibit efavirenz 8-hydroxylation by HLMs, both rifampin (apparent inhibition constant [Ki] = 368 μM) and pyrazinamide (Ki = 637 μM) showed relatively weak inhibition of efavirenz 7-hydroxylation. Importantly, isoniazid demonstrated potent time-dependent inhibition of efavirenz 7-hydroxylation in both HLMs (inhibitor concentration required for half-maximal inactivation [KI] = 30 μM; maximal rate constant of inactivation [kinact] = 0.023 min(-1)) and recombinant CYP2A6 (KI = 15 μM; kinact = 0.024 min(-1)) and also formed a metabolite intermediate complex consistent with mechanism-based inhibition. Selective inhibition of the CYP2B6.6 allozyme could not be demonstrated for any of the antituberculosis drugs using either recombinant enzymes or CYP2B6*6 genotype HLMs. In conclusion, the results of this study identify isoniazid as the most likely perpetrator of this clinically important drug-drug interaction through mechanism-based inactivation of CYP2A6.
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Affiliation(s)
- Michael H Court
- Individualized Medicine Program, Department of Veterinary Clinical Sciences, Washington State University College of Veterinary Medicine, Pullman, Washington, USA
| | - Fawziah E Almutairi
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts, USA Program in Pharmacology and Experimental Therapeutics, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
| | - David J Greenblatt
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Suwagmani Hazarika
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Hongyan Sheng
- Individualized Medicine Program, Department of Veterinary Clinical Sciences, Washington State University College of Veterinary Medicine, Pullman, Washington, USA
| | - Kathrin Klein
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, and University of Tübingen, Tübingen, Germany
| | - Ulrich M Zanger
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, and University of Tübingen, Tübingen, Germany
| | - Joanne Bourgea
- BD Biosciences, Discovery Labware, Woburn, Massachusetts, USA
| | | | - Awewura Kwara
- Warren Alpert Medical School of Brown University and The Miriam Hospital, Providence, Rhode Island, USA
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22
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Penell J, Lind L, Fall T, Syvänen AC, Axelsson T, Lundmark P, Morris AP, Lindgren C, Mahajan A, Salihovic S, van Bavel B, Ingelsson E, Lind PM. Genetic variation in the CYP2B6 gene is related to circulating 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) concentrations: an observational population-based study. Environ Health 2014; 13:34. [PMID: 24885815 PMCID: PMC4024654 DOI: 10.1186/1476-069x-13-34] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 04/28/2014] [Indexed: 05/16/2023]
Abstract
BACKGROUND Since human CYP2B6 has been identified as the major CYP enzyme involved in the metabolism of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and that human 2B6 is a highly polymorphic CYP, with known functional variants, we evaluated if circulating concentrations of a major brominated flame retardant, BDE-47, were related to genetic variation in the CYP2B6 gene in a population sample. METHODS In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (men and women all aged 70), 25 single nucleotide polymorphisms (SNPs) in the CYP2B6 gene were genotyped. Circulating concentrations of BDE-47 were analyzed by high-resolution gas chromatography coupled to high-resolution mass spectrometry (HRGC/ HRMS). RESULTS Several SNPs in the CYP2B6 gene were associated with circulating concentrations of BDE-47 (P = 10-4 to 10-9). The investigated SNPs came primarily from two haplotypes, although the correlation between the haplotypes was rather high. Conditional analyses adjusting for the SNP with the strongest association with the exposure (rs2014141) did not provide evidence for independent signals. CONCLUSION Circulating concentrations of BDE-47 were related to genetic variation in the CYP2B6 gene in an elderly population.
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Affiliation(s)
- Johanna Penell
- Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, Uppsala, Sweden
| | - Lars Lind
- Department of Medical Sciences, Cardiovascular Epidemiology, Uppsala University, Uppsala, Sweden
| | - Tove Fall
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Anne-Christine Syvänen
- Department of Medical Sciences, Molecular Medicine and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Tomas Axelsson
- Department of Medical Sciences, Molecular Medicine and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Per Lundmark
- Department of Medical Sciences, Molecular Medicine and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Andrew P Morris
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Cecilia Lindgren
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Anubha Mahajan
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Samira Salihovic
- MTM Research Centre, School of Science and Technology, Örebro University, Örebro, Sweden
| | - Bert van Bavel
- MTM Research Centre, School of Science and Technology, Örebro University, Örebro, Sweden
| | - Erik Ingelsson
- Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - P Monica Lind
- Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, Uppsala, Sweden
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23
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Daraki A, Zachaki S, Koromila T, Diamantopoulou P, Pantelias GE, Sambani C, Aleporou V, Kollia P, Manola KN. The G⁵¹⁶T CYP2B6 germline polymorphism affects the risk of acute myeloid leukemia and is associated with specific chromosomal abnormalities. PLoS One 2014; 9:e88879. [PMID: 24586425 PMCID: PMC3933334 DOI: 10.1371/journal.pone.0088879] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/16/2014] [Indexed: 01/11/2023] Open
Abstract
The etiology of acute myeloid leukemia (AML) underlies the influence of genetic variants in candidate genes. The CYP2B6 enzyme detoxifies many genotoxic xenobiotics, protecting cells from oxidative damage. The CYP2B6 gene is subjected to a single-nucleotide polymorphism (G⁵¹⁶T) with heterozygotes (GT) and homozygotes (TT) presenting decreased enzymatic activity. This case-control study aimed to investigate the association of CYP2B6 G⁵¹⁶T polymorphism with the susceptibility of AML and its cytogenetic and clinical characteristics. Genotyping was performed on 619 AML patients and 430 healthy individuals using RCR-RFLP and a novel LightSNip assay. The major finding was a statistically higher frequency of the variant genotypes (GT and TT) in patients compared to the controls (GT:38.8% vs 29.8% and TT:9.3% vs 5.3% respectively) (p<0.001). More specifically, a significantly higher frequency of GT+TT genotypes in de novo AML patients (46.6%) and an immensely high frequency of TT in secondary AML (s-AML) (20.5%) were observed. The statistical analysis showed that the variant T allele was approximately 1.5-fold and 2.4-fold higher in de novo and s-AML respectively than controls. Concerning FAB subtypes, the T allele presented an almost 2-fold increased in AML-M2. Interestingly, a higher incidence of the TT genotype was observed in patients with abnormal karyotypes. In particular, positive correlations of the mutant allele were found in patients carrying specific chromosomal aberrations [-7/del(7q), -5/del(5q), +8, +21 or t(8;21)], complex or monosomal karyotypes. Finally, a strikingly higher frequency of TT genotype was also observed in patients stratified to the poor risk group. In conclusion, our results provide evidence for the involvement of the CYP2B6 polymorphism in AML susceptibility and suggest a possible role of the CYP2B6 genetic background on the development of specific chromosomal aberrations.
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Affiliation(s)
- Aggeliki Daraki
- Laboratory of Health Physics, Radiobiology & Cytogenetics, National Centre for Scientific Research (NCSR) “Demokritos”, Athens, Greece
- Department of Genetics & Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Sophia Zachaki
- Laboratory of Health Physics, Radiobiology & Cytogenetics, National Centre for Scientific Research (NCSR) “Demokritos”, Athens, Greece
| | - Theodora Koromila
- Department of Genetics & Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Paraskevi Diamantopoulou
- Laboratory of Health Physics, Radiobiology & Cytogenetics, National Centre for Scientific Research (NCSR) “Demokritos”, Athens, Greece
| | - Gabriel E. Pantelias
- Laboratory of Health Physics, Radiobiology & Cytogenetics, National Centre for Scientific Research (NCSR) “Demokritos”, Athens, Greece
| | - Constantina Sambani
- Laboratory of Health Physics, Radiobiology & Cytogenetics, National Centre for Scientific Research (NCSR) “Demokritos”, Athens, Greece
| | - Vasiliki Aleporou
- Department of Genetics & Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagoula Kollia
- Department of Genetics & Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Kalliopi N. Manola
- Laboratory of Health Physics, Radiobiology & Cytogenetics, National Centre for Scientific Research (NCSR) “Demokritos”, Athens, Greece
- * E-mail:
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24
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Allele and genotype frequencies of CYP2B6 in a Turkish population. Mol Biol Rep 2014; 41:3891-6. [PMID: 24562623 DOI: 10.1007/s11033-014-3256-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 02/08/2014] [Indexed: 01/11/2023]
Abstract
Increasing interest in cytochrome P450 2B6 (CYP2B6) genetic polymorphism was stimulated by revelations of a specific CYP2B6 genotype significantly affecting the metabolism of various drugs in common clinical use in terms of increasing drug efficacy and avoiding adverse drug reactions. The present study aimed to determine the frequencies of CYP2B6*4 CYP2B6*5, CYP2B6*6, CYP2B6*7 and CYP2B6*9 alleles in healthy Turkish individuals (n = 172). Frequencies of three single nucleotide polymorphisms were 516G>T (28%), 785A>G (33%), and 1459C>T (12%). The frequencies of CYP2B6*1, *4, *5, *6, *7, and *9 alleles were 54.3 (95% CI 49.04-59.56), 6.4% (95% CI 3.81-8.99), 11% (95% CI 7.69-14.31), 25.3% (95% CI 20.71-29.89), 0.87% (95% CI -0.11-1.85) and 2.0% (95% CI 0.52-3.48), respectively. Allele *6 was more frequent (25.3%) than the other variant alleles in Turkish subjects. The frequencies of CYP2B6*4, *5, *6, *7, and *9 alleles were similar to European populations but significantly different from that reported for Asian populations. This is the first study to document the frequencies of the CYP2B6*4, *5, *6, *7, *9 alleles in the healthy Turkish individuals and our results could provide clinically useful information on drug metabolism by CYP2B6 in Turkish population.
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25
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Xu C, Quinney SK, Guo Y, Hall SD, Li L, Desta Z. CYP2B6 pharmacogenetics-based in vitro-in vivo extrapolation of efavirenz clearance by physiologically based pharmacokinetic modeling. Drug Metab Dispos 2013; 41:2004-11. [PMID: 23846872 DOI: 10.1124/dmd.113.051755] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Efavirenz is mainly cleared by CYP2B6. The CYP2B6*6 allele is associated with lower efavirenz clearance. Efavirenz clearance was predictable using in vitro data for carriers of the CYP2B6*1/*1 genotype, but the prediction in carriers of the CYP2B6*6 allele was poor. To test the hypothesis that incorporation of mechanism of reduced efavirenz metabolism by the CYP2B6*6 allele can predict the genetic effect on efavirenz pharmacokinetics, in vitro-in vivo extrapolation of efavirenz clearance was performed by physiologically based pharmacokinetic modeling (Simcyp Simulator; Simcyp Ltd., Sheffield, UK) using data obtained from expressed CYP2B6.1 and CYP2B6.6 as well as human liver microsomes (HLMs) with CYP2B6*1/*1, *1/*6, and *6/*6 genotypes. Simulated pharmacokinetics of a single 600-mg oral dose of efavirenz for individuals with each genotype was compared with data observed in healthy subjects genotyped for the CYP2B6*6 allele (n = 20). Efavirenz clearance for carriers of the CYP2B6*1/*1 genotype was predicted reasonably well using HLM data, but the clearance in carriers of the CYP2B6*6 allele was underpredicted using both expressed and HLM systems. Improved prediction of efavirenz clearance was obtained from expressed CYP2B6 after recalculating intersystem extrapolation factors for CYP2B6.1 and CYP2B6.6 based on in vitro intrinsic clearance of bupropion 4-hydroxylation. These findings suggest that genetic effect on both CYP2B6 protein expression and catalytic efficiency needs to be taken into account for the prediction of pharmacokinetics in individuals carrying the CYP2B6*6/*6 genotype. Expressed CYP2B6 proteins may be a reliable in vitro system to predict effect of the CYP2B6*6 allele on the metabolism of CYP2B6 substrates.
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Affiliation(s)
- Cong Xu
- Division of Clinical Pharmacology (C.X., Z.D.), Department of Obstetrics and Gynecology (S.K.Q.) and Center for Computational Biology and Bioinformatics (L.L.), Indiana University School of Medicine, Indianapolis, Indiana; and Department of Drug Disposition, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana (Y.G., S.D.H.)
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26
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Erratico CA, Szeitz A, Bandiera SM. Biotransformation of 2,2′,4,4′-Tetrabromodiphenyl Ether (BDE-47) by Human Liver Microsomes: Identification of Cytochrome P450 2B6 as the Major Enzyme Involved. Chem Res Toxicol 2013; 26:721-31. [DOI: 10.1021/tx300522u] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Claudio A. Erratico
- Faculty of Pharmaceutical
Sciences, The University of British Columbia, Vancouver, British Columbia,
Canada V6T 1Z3
| | - András Szeitz
- Faculty of Pharmaceutical
Sciences, The University of British Columbia, Vancouver, British Columbia,
Canada V6T 1Z3
| | - Stelvio M. Bandiera
- Faculty of Pharmaceutical
Sciences, The University of British Columbia, Vancouver, British Columbia,
Canada V6T 1Z3
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27
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Zanger UM, Klein K. Pharmacogenetics of cytochrome P450 2B6 (CYP2B6): advances on polymorphisms, mechanisms, and clinical relevance. Front Genet 2013; 4:24. [PMID: 23467454 PMCID: PMC3588594 DOI: 10.3389/fgene.2013.00024] [Citation(s) in RCA: 206] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 02/14/2013] [Indexed: 12/22/2022] Open
Abstract
Cytochrome P450 2B6 (CYP2B6) belongs to the minor drug metabolizing P450s in human liver. Expression is highly variable both between individuals and within individuals, owing to non-genetic factors, genetic polymorphisms, inducibility, and irreversible inhibition by many compounds. Drugs metabolized mainly by CYP2B6 include artemisinin, bupropion, cyclophosphamide, efavirenz, ketamine, and methadone. CYP2B6 is one of the most polymorphic CYP genes in humans and variants have been shown to affect transcriptional regulation, splicing, mRNA and protein expression, and catalytic activity. Some variants appear to affect several functional levels simultaneously, thus, combined in haplotypes, leading to complex interactions between substrate-dependent and -independent mechanisms. The most common functionally deficient allele is CYP2B6*6 [Q172H, K262R], which occurs at frequencies of 15 to over 60% in different populations. The allele leads to lower expression in liver due to erroneous splicing. Recent investigations suggest that the amino acid changes contribute complex substrate-dependent effects at the activity level, although data from recombinant systems used by different researchers are not well in agreement with each other. Another important variant, CYP2B6*18 [I328T], occurs predominantly in Africans (4-12%) and does not express functional protein. A large number of uncharacterized variants are currently emerging from different ethnicities in the course of the 1000 Genomes Project. The CYP2B6 polymorphism is clinically relevant for HIV-infected patients treated with the reverse transcriptase inhibitor efavirenz, but it is increasingly being recognized for other drug substrates. This review summarizes recent advances on the functional and clinical significance of CYP2B6 and its genetic polymorphism, with particular emphasis on the comparison of kinetic data obtained with different substrates for variants expressed in different recombinant expression systems.
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Affiliation(s)
- Ulrich M Zanger
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology Stuttgart, Germany ; The University of Tuebingen Tuebingen, Germany
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28
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Mayumi K, Hanioka N, Masuda K, Koeda A, Naito S, Miyata A, Narimatsu S. Characterization of marmoset CYP2B6: cDNA cloning, protein expression and enzymatic functions. Biochem Pharmacol 2013; 85:1182-94. [PMID: 23395694 DOI: 10.1016/j.bcp.2013.01.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 01/28/2013] [Accepted: 01/28/2013] [Indexed: 02/05/2023]
Abstract
The common marmoset is a promising species for evaluating the safety of drug candidates. To further understand the capacity for drug metabolism in marmosets, a cDNA encoding a CYP2B enzyme was cloned from the total RNA fraction of marmoset liver by 3'- and 5'-RACE methods. Nucleotide and deduced amino acid sequences showed 90.8 and 86.2% identity, respectively, with human CYP2B6. The marmoset CYP2B6 (marCYP2B6) protein was expressed in insect cells, and its enzymatic properties were compared with those of human (humCYP2B6) and cynomolgus monkey (cynCYP2B6) orthologs in liver and insect cell microsomes. Enzymatic functions were examined for the oxidation of 7-ethoxy-4-(trifluoromethyl)coumarin (7-ETC), bupropion (BUP) and efavirenz (EFV). The kinetic profiles for the oxidation of the three substrates by liver microsomal fractions were similar between humans and cynomolgus monkeys (biphasic for 7-ETC and monophasic for BUP and EFV), but that of marmosets was unique (monophasic for 7-ETC and biphasic for BUP and EFV). Recombinant enzymes, humCYP2B6 and cynCYP2B6, also yielded similar kinetic profiles for the oxidation of the three substrates, whereas marCYP2B6 showed activity only for 7-ETC hydroxylation. In silico docking simulations suggested that two amino acid residues, Val-114 and Leu-367, affect the activity of marCYP2B6. In fact, a marCYP2B6 mutant with substitutions V114I and L367V exhibited BUP hydroxylase activity that was 4-fold higher than that of humCYP2B6, while its EFV 8-hydroxylase activity was only 10% that of the human enzyme. These results indicate that the amino acids at positions 114 and 367 affect the enzymatic capacity of marmoset CYP2B6.
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Affiliation(s)
- Kei Mayumi
- Laboratory of Health Chemistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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29
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Gadel S, Crafford A, Regina K, Kharasch ED. Methadone N-demethylation by the common CYP2B6 allelic variant CYP2B6.6. Drug Metab Dispos 2013; 41:709-13. [PMID: 23298862 DOI: 10.1124/dmd.112.050625] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The long-acting opioid methadone displays considerable unexplained interindividual pharmacokinetic variability. Methadone metabolism clinically occurs primarily by N-demethylation to 2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), catalyzed predominantly by CYP2B6. Retrospective studies suggest that the common allele variant CYP2B6*6 may influence methadone plasma concentrations. The catalytic activity of CYP2B6.6, encoded by CYP2B6*6, is highly substrate-dependent. This investigation compared methadone N-demethylation by CYP2B6.6 with that by wild-type CYP2B6.1. Methadone enantiomer and racemate N-demethylation by recombinant-expressed CYP2B6.6 and CYP2B6.1 was determined. At substrate concentrations (0.25-2 µM) approximating plasma concentrations occurring clinically, rates of methadone enantiomer N-demethylation by CYP2B6.6, incubated individually or as the racemate, were one-third to one-fourth those by CYP2B6.1. For methadone individual enantiomers and metabolism by CYP2B6.6 compared with CYP2B6.1, Vmax was diminished, Ks was greater and the in vitro intrinsic clearance was diminished 5- to 6-fold. The intrinsic clearance for R- and S-EDDP formation from racemic methadone was diminished approximately 6-fold and 3-fold for R- and S-methadone, respectively. Both CYP2B6.6 and CYP2B6.1 showed similar stereoselectivity (S>R-methadone). Human liver microsomes with diminished CYP2B6 content due to a CYP2B6*6 allele had lower rates of methadone N-demethylation. Results show that methadone N-demethylation catalyzed by CYP2B6.6, the CYP2B6 variant encoded by the CYP2B6*6 polymorphism, is catalytically deficient compared with wild-type CYP2B6.1. Diminished methadone N-demethylation by CYP2B6.6 may provide a mechanistic explanation for clinical observations of altered methadone disposition in individuals carrying the CYP2B6*6 polymorphism.
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Affiliation(s)
- Sarah Gadel
- Department of Anesthesiology, Division of Clinical and Translational Research, Washington University in St. Louis, St. Louis, Missouri 63110-1093, USA
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30
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Varshney E, Saha N, Tandon M, Shrivastava V, Ali S. Prevalence of poor and rapid metabolizers of drugs metabolized by CYP2B6 in North Indian population residing in Indian national capital territory. SPRINGERPLUS 2012; 1:34. [PMID: 23961363 PMCID: PMC3725906 DOI: 10.1186/2193-1801-1-34] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 10/08/2012] [Indexed: 01/11/2023]
Abstract
Identification of poor and rapid metabolizers for the category of drugs metabolized by cytochrome P450 2B6 (CYP2B6) is important for understanding the differences in clinical responses of drugs metabolized by this enzyme. This study reports the prevalence of poor and rapid metabolizers in North Indian population residing in the National Capital Territory. The prevalence of poor and rapid metabolizers was determined in the target population for the category of drugs metabolized by CYP2B6 by measuring plasma bupropion, a drug metabolized by CYP2B6, and its metabolite. Bupropion (75 mg) was administered to 107 volunteers, and the drug (bupropion) and its metabolite (hydroxybupropion) were determined simultaneously by LCMS/MS in the plasma. CYP2B6 activity was measured as hydroxybupropion/bupropion ratio, and volunteers were categorized as rapid or poor metabolizers on the basis of cutoff value of log (hydroxybupropion/bupropion). Significant differences were observed between the mean metabolite/drug ratio of rapid metabolizers (Mean = 0.59) and poor metabolizers (Mean = 0.26) with p<0.0001. Results indicate that 20.56% individuals in the target population were poor metabolizers for the category of drugs metabolized by CYP2B6. Cutoff value defined in this study can be used as a tool for evaluating the status of CYP2B6 using bupropion as a probe drug. The baseline information would be clinically useful before administering the drugs metabolized by this isoform.
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Affiliation(s)
- Ekta Varshney
- Department of Biochemistry, Jamia Hamdard, Hamdard Nagar, New Delhi, 110062 India
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31
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Cytochrome P450 2B diversity and dietary novelty in the herbivorous, desert woodrat (Neotoma lepida). PLoS One 2012; 7:e41510. [PMID: 22927909 PMCID: PMC3425548 DOI: 10.1371/journal.pone.0041510] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 06/22/2012] [Indexed: 01/12/2023] Open
Abstract
Detoxification enzymes play a key role in plant-herbivore interactions, contributing to the on-going evolution of ecosystem functional diversity. Mammalian detoxification systems have been well studied by the medical and pharmacological industries to understand human drug metabolism; however, little is known of the mechanisms employed by wild herbivores to metabolize toxic plant secondary compounds. Using a wild rodent herbivore, the desert woodrat (Neotoma lepida), we investigated genomic structural variation, sequence variability, and expression patterns in a multigene subfamily involved in xenobiotic metabolism, cytochrome P450 2B (CYP2B). We hypothesized that differences in CYP2B expression and sequence diversity could explain differential abilities of woodrat populations to consume native plant toxins. Woodrats from two distinct populations were fed diets supplemented with either juniper (Juniperus osteosperma) or creosote bush (Larrea tridentata), plants consumed by woodrats in their respective desert habitats. We used Southern blot and quantitative PCR to determine that the genomic copy number of CYP2B in both populations was equivalent, and similar in number to known rodent copy number. We compared CYP2B expression patterns and sequence diversity using cloned hepatic CYP2B cDNA. The resulting sequences were very diverse, and clustered into four major clades by amino acid similarity. Sequences from the experimental treatments were distributed non-randomly across a CYP2B tree, indicating unique expression patterns from woodrats on different diets and from different habitats. Furthermore, within each major CYP2B clade, sequences shared a unique combination of amino acid residues at 13 sites throughout the protein known to be important for CYP2B enzyme function, implying differences in the function of each major CYP2B variant. This work is the most comprehensive investigation of the genetic diversity of a detoxification enzyme subfamily in a wild mammalian herbivore, and contributes an initial genetic framework to our understanding of how a wild herbivore responds to critical changes in its diet.
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Abstract
Chlorpyrifos (CPF), an organophosphorus (OP) pesticide, is bioactivated by cytochrome P450s (CYPs) to the active metabolite chlorpyrifos oxon (CPF-O). Given that human CYP2B6 has the highest intrinsic clearance (CL(int)) for CPF bioactivation, CYP2B6 polymorphisms may impact human susceptibility to CPF at real world environmental and occupational CPF exposure levels. CYP2B6.4,.5,.7, and .18 were over-expressed in mammalian COS-1 cells to assess the impact of CYP2B6 variants on the K(m) and V(max) for bioactivation of CPF. Cell lysates were incubated with CPF (0-100 μM) and the production of CPF-O was measured via HPLC analysis. CYP2B6 content was determined by western blot. CYP2B6.18 had neither detectable protein nor activity levels. The V(max) value for each remaining variant was significantly higher than wild-type (CYP2B6.1, V(max) 4.13 × 10(4) pmol/min/nmol CYP2B6), with CYP2B6.4,.5, and .7 having V(max) values of 4.52 × 10(5), 1.82 × 10(5), and 9.60 × 10(4) pmol/min/nmol CYP2B6, respectively. The K(m) values for these variants ranged from 0.39 to 1.09 μM and were not significantly different from wild-type. All active variants examined had significantly higher CL(int) than CYP2B6.1. Variants of CYP2B6 have altered capacity to bioactivate CPF and may affect individual susceptibility by altering the V(max) for CPF-O formation.
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Affiliation(s)
- Alice L Crane
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, NY, USA
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33
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Yang J, He MM, Niu W, Wrighton SA, Li L, Liu Y, Li C. Metabolic capabilities of cytochrome P450 enzymes in Chinese liver microsomes compared with those in Caucasian liver microsomes. Br J Clin Pharmacol 2012; 73:268-84. [PMID: 21815912 DOI: 10.1111/j.1365-2125.2011.04076.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
AIM The most common causes of variability in drug response include differences in drug metabolism, especially when the hepatic cytochrome P450 (CYP) enzymes are involved. The current study was conducted to assess the differences in CYP activities in human liver microsomes (HLM) of Chinese or Caucasian origin. METHODS The metabolic capabilities of CYP enzymes in 30 Chinese liver microsomal samples were compared with those of 30 Caucasian samples utilizing enzyme kinetics. Phenacetin O-deethylation, coumarin 7-hydroxylation, bupropion hydroxylation, amodiaquine N-desethylation, diclofenac 4'-hydroxylation (S)-mephenytoin 4'-hydroxylation, dextromethorphan O-demethylation, chlorzoxazone 6-hydroxylation and midazolam 1'-hydroxylation/testosterone 6β-hydroxylation were used as probes for activities of CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A, respectively. Mann-Whitney U test was used to assess the differences. RESULTS The samples of the two ethnic groups were not significantly different in cytochrome-b(5) concentrations but were significantly different in total CYP concentrations and NADPH-P450 reductase activity (P < 0.05). Significant ethnic differences in intrinsic clearance were observed for CYP1A2, CYP2C9, CYP2C19 and CYP2E1; the median values of the Chinese group were 54, 58, 26, and 35% of the corresponding values of the Caucasian group, respectively. These differences were associated with differences in Michaelis constant or maximum velocity. Despite negligible difference in intrinsic clearance, the Michaelis constant of CYP2B6 appeared to have a significant ethnic difference. No ethnic difference was observed for CYP2A6, CYP2C8, CYP2D6 and CYP3A. CONCLUSIONS These data extend our knowledge on the ethnic differences in CYP enzymes and will have implications for drug discovery and drug therapy for patients from different ethnic origins.
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Affiliation(s)
- Junling Yang
- Shanghai Institute of Materia, Chinese Academy of Sciences, Shanghai, China
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34
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Xu C, Ogburn ET, Guo Y, Desta Z. Effects of the CYP2B6*6 allele on catalytic properties and inhibition of CYP2B6 in vitro: implication for the mechanism of reduced efavirenz metabolism and other CYP2B6 substrates in vivo. Drug Metab Dispos 2012; 40:717-25. [PMID: 22232427 DOI: 10.1124/dmd.111.042416] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The mechanism by which CYP2B6*6 allele alters drug metabolism in vitro and in vivo is not fully understood. To test the hypothesis that altered substrate binding and/or catalytic properties contribute to its functional consequences, efavirenz 8-hydroxylation and bupropion 4-hydroxylation were determined in CYP2B6.1 and CYP2B6.6 proteins expressed without and with cytochrome b5 (Cyt b5) and in human liver microsomes (HLMs) obtained from liver tissues genotyped for the CYP2B6*6 allele. The susceptibility of the variant protein to inhibition was also tested in HLMs. Significantly higher V(max) and K(m) values for 8-hydroxyefavirenz formation and ∼2-fold lower intrinsic clearance (Cl(int)) were noted in expressed CYP2B6.6 protein (-b5) compared with that of CYP2B6.1 protein (-b5); this effect was abolished by Cyt b5. The V(max) and Cl(int) values for 4-hydroxybupropion formation were significantly higher in CYP2B6.6 than in CYP2B6.1 protein, with no difference in K(m), whereas coexpression with Cyt b5 reversed the genetic effect on these kinetic parameters. In HLMs, CYP2B6*6/*6 genotype was associated with markedly lower V(max) (and moderate increase in K(m)) and thus lower Cl(int) values for efavirenz and bupropion metabolism, but no difference in catalytic properties was noted between CYP2B6*1/*1 and CYP2B6*1/*6 genotypes. Inhibition of efavirenz 8-hydroxylation by voriconazole was significantly greater in HLMs with the CYP2B6*6 allele (K(i) = 1.6 ± 0.8 μM) than HLMs with CYP2B6*1/*1 genotype (K(i) = 3.0 ± 1.1 μM). In conclusion, our data suggest the CYP2B6*6 allele influences metabolic activity by altering substrate binding and catalytic activity in a substrate- and Cyt b5-dependent manner. It may also confer susceptibility to inhibition.
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Affiliation(s)
- Cong Xu
- Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Ellison CA, Abou El-Ella SS, Tawfik M, Lein PJ, Olson JR. Allele and genotype frequencies of CYP2B6 and CYP2C19 polymorphisms in Egyptian agricultural workers. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2012; 75:232-241. [PMID: 22352331 PMCID: PMC3500531 DOI: 10.1080/15287394.2012.641201] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Genetic variability in cytochrome P-450 (CYP) has the potential to modify pharmacological and toxicological responses to many chemicals. Both CYP2B6 and CYP2C19 are pharmacologically and toxicologically relevant due to their ability to metabolize multiple drugs and environmental contaminants, including the organophosphorus (OP) pesticide chlorpyrifos. The aim of this study was to determine the prevalence of CYP2B6 and CYP2C19 variants in an indigenous Egyptian population (n = 120) that was shown to be occupationally exposed to chlorpyrifos. Further, the genotyping data was compared for Egyptians with previously studied populations to determine between population differences. Allelic frequencies were CYP2B6 1459C > T (3.8%), CYP2B6 785A > G (30.4%), CYP2B6 516G > T (28.8%), CYP2C19 681G > A (3.8%), and CYP2C19 431G > A (0%). The most prevalent CYP2B6 genotype combinations were CYP2B6 *1/*1 (44%), *1/*6 (38%), *6/*6 (8%), and *1/*5 (6%). The frequency of the CYP2C19 genotype combinations were CYP2C19 *1/*1 (93%), *1/*2 (6%), and *2/*2 (1%). The frequency of the CYP2B6 516G > T and CYP2B6 785A > G polymorphisms in this Egyptian cohort is similar to that found North American and European populations but significantly different from that reported for West African populations, while that of CYP2B6 1459C > T is similar to that found in Africans and African Americans. The observed frequency of CYP2C19 681G > A in Egyptians is similar to that of African pygmies but significantly different from other world populations, while CYP2C19 431 G > A was significantly different from that of African pygmies but similar to other world populations.
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Affiliation(s)
- Corie A Ellison
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14214, USA.
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Nuclear receptor-mediated induction of CYP450 by antiretrovirals: functional consequences of NR1I2 (PXR) polymorphisms and differential prevalence in whites and sub-Saharan Africans. J Acquir Immune Defic Syndr 2011; 55:536-49. [PMID: 20861742 DOI: 10.1097/qai.0b013e3181f52f0c] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Antiretroviral therapy including HIV protease inhibitors and nonnucleoside reverse transcriptase inhibitors can both inhibit and induce expression of cytochrome P450s, potentially leading to drug interactions. However, information is lacking on the impact of genetic polymorphism on this interaction. METHODS This study examines the prevalence of 33 polymorphisms in NR1I2 (pregnane X receptor [PXR]), CYP3A4, and CYP2B6 in 1013 white and sub-Saharan African patients with HIV; explores the inductive ability of 16 antiretrovirals on CYP3A4 and CYP2B6 promoter activity through nuclear receptors PXR and constitutive androstane receptor (CAR); and evaluates the influence of naturally occurring PXR genetic variants on antiretroviral activation. RESULTS Seventeen polymorphisms were present at different frequencies between the two ethnicities. Darunavir, fosamprenavir, lopinavir, nelfinavir, tipranavir, efavirenz, and abacavir increased CYP3A4 and/or CYP2B6 promoter activity, some through constitutive androstane receptor but mainly through PXR. Addition of low-dose ritonavir enhanced levels of CYP promoter activity for several protease inhibitors. Some PXR variants displayed lower fosamprenavir- and lopinavir-induced CYP3A4 promoter activity than the PXR reference sequence, whereas efavirenz and nelfinavir induction was unchanged. CONCLUSIONS The presence of NR1I2 polymorphisms can alter the induction of CYP3A4 and CYP2B6 promoter activity, potentially adding to the unpredictable nature of antiretroviral drug interactions. These polymorphisms differ in prevalence between whites and sub-Saharan Africans.
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Abstract
The cytochrome P450 (CYP) superfamily is one of the most important groups of enzymes involved in drug metabolism. It is responsible for the metabolism of a large number of drugs. Many CYP isoforms are expressed polymorphically, and catalytic alterations of allelic variant proteins can affect the metabolic activities of many drugs. The CYP2D6, CYP2C9, CYP2C19, and CYP2B6 genes are particularly polymorphic, whereas CYP1A1, CYP1A2, CYP2E1, and CYP3A4 are relatively well conserved without common functional polymorphisms. In vitro studies using cDNA expression systems are useful tools for evaluating functional alterations of the allelic variants of CYP, particularly for low-frequency alleles. Recombinant CYPs have been successfully expressed in bacteria, yeast, baculoviruses, and several mammalian cells. Determination of CYP variant-mediated kinetic parameters (Km and Vmax) in vitro can be useful for predicting drug dosing and clearance in humans. This review focuses on the advantages and disadvantages of the various cDNA-expression systems used to determine the kinetic parameters for CYP allelic variants, the methods for determining the kinetic parameters, and the findings of in vitro studies on highly polymorphic CYPs, including CYP2D6, CYP2C9, CYP2C19, and CYP2B6.
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Affiliation(s)
- Masahiro Hiratsuka
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
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Characterization of inhibitory effects of perfluorooctane sulfonate on human hepatic cytochrome P450 isoenzymes: Focusing on CYP2A6. Chem Biol Interact 2011; 194:120-6. [DOI: 10.1016/j.cbi.2011.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 09/02/2011] [Accepted: 09/09/2011] [Indexed: 11/24/2022]
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Phan VH, Tan C, Rittau A, Xu H, McLachlan AJ, Clarke SJ. An update on ethnic differences in drug metabolism and toxicity from anti-cancer drugs. Expert Opin Drug Metab Toxicol 2011; 7:1395-410. [PMID: 21950349 DOI: 10.1517/17425255.2011.624513] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Based on recent emerging evidence of inter-ethnic differences in drug response and toxicity, ethnic diversity in pharmacokinetics, pharmacogenomics and clinical outcomes are being increasingly investigated. Ultimately, this will promote improved understanding of inter-individual differences in the pharmacokinetics and tolerance of cytotoxic drugs. AREAS COVERED This article reviews potential explanations for the observed ethnic differences in treatment outcomes and provides clinical data to support this concept. A literature search was implemented on PubMed and PharmGKB to investigate the areas of ethnic differences in pharmacogenomics, pharmacogenetics and clinical outcomes of cancer therapies. EXPERT OPINION There has been a relative paucity of clinical evidence linking genetic polymorphisms of genes encoding drug-metabolizing enzymes to the pharmacokinetics, pharmacodynamics and tolerance of anti-cancer drugs. Future research should focus on studies using large sample sizes, in the hope that they will provide results of high clinical significance. Due to the potential for ethnic differences to impact on both toxicities and benefits of systemic cancer therapies, the development of new therapeutic agents should include patients from diverse geographical ancestries in each phase of drug development.
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Affiliation(s)
- Viet Hong Phan
- The University of Sydney, Concord Repatriation General Hospital, Sydney Cancer Centre, Concord, NSW, Sydney, Australia
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40
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Gozalo C, Gérard L, Loiseau P, Morand-Joubert L, Peytavin G, Molina JM, Dellamonica P, Becquemont L, Aboulker JP, Launay O, Verstuyft C. Pharmacogenetics of toxicity, plasma trough concentration and treatment outcome with nevirapine-containing regimen in anti-retroviral-naïve HIV-infected adults: an exploratory study of the TRIANON ANRS 081 trial. Basic Clin Pharmacol Toxicol 2011; 109:513-20. [PMID: 21824325 DOI: 10.1111/j.1742-7843.2011.00780.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The aim of this exploratory study was to investigate in a homogeneous population of anti-retroviral naïve HIV-1-infected adults, the relationships between genetic polymorphisms involved in nevirapine metabolism [CYP2B6 516G>T, 785A>G and 1459C>T; CYP3A5 6986A>G (CYP3A5*3)], transport (ABCB1 2677G>T/A and 3435C>T), and antigen recognition (HLA-DRB1*0101), and the hepatic and/or cutaneous toxicity occurring within the first 8 or 72 weeks of treatment, plasma trough concentrations (C(trough) ) at week 8 and immuno-virological response to nevirapine at week 24. Associations between genetic polymorphisms and toxicity, C(trough) and response to nevirapine were performed in a population of 72 HIV-1 positive and nevirapine-treated patients followed during 72 weeks, as part of the previous study called: ANRS081 'Trianon' trial. Among the 18 patients who developed toxicity events during the 72 weeks of the study, 12 patients exhibited early toxicity before week 8. No significant association could be evidenced between any of the analysed single nucleotide polymorphisms (SNPs) and nevirapine early or global toxicity, pharmacokinetics and immuno-virological responses even though a possible association between CYP2B6 516G>T and 1459C>T and the trough level of nevirapine was suggested.
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Affiliation(s)
- Claire Gozalo
- Department of Molecular Genetics, Pharmacogenetics and Hormonology, Assistance Publique-Hôpitaux de Paris, Bicêtre Hospital, France
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Ariyoshi N, Ohara M, Kaneko M, Afuso S, Kumamoto T, Nakamura H, Ishii I, Ishikawa T, Kitada M. Q172H Replacement Overcomes Effects on the Metabolism of Cyclophosphamide and Efavirenz Caused by CYP2B6 Variant with Arg262. Drug Metab Dispos 2011; 39:2045-8. [DOI: 10.1124/dmd.111.039586] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Honda M, Muroi Y, Tamaki Y, Saigusa D, Suzuki N, Tomioka Y, Matsubara Y, Oda A, Hirasawa N, Hiratsuka M. Functional Characterization of CYP2B6 Allelic Variants in Demethylation of Antimalarial Artemether. Drug Metab Dispos 2011; 39:1860-5. [DOI: 10.1124/dmd.111.040352] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Genetically Polymorphic Cytochrome P450s and Transporters and Personalized Antimicrobial Chemotherapy. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch52] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Zhang H, Sridar C, Kenaan C, Amunugama H, Ballou DP, Hollenberg PF. Polymorphic variants of cytochrome P450 2B6 (CYP2B6.4-CYP2B6.9) exhibit altered rates of metabolism for bupropion and efavirenz: a charge-reversal mutation in the K139E variant (CYP2B6.8) impairs formation of a functional cytochrome p450-reductase complex. J Pharmacol Exp Ther 2011; 338:803-9. [PMID: 21659470 DOI: 10.1124/jpet.111.183111] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, metabolism of bupropion, efavirenz, and 7-ethoxy-4-trifluoromethylcoumarin (7-EFC) by CYP2B6 wild type (CYP2B6.1) and six polymorphic variants (CYP2B6.4 to CYP2B6.9) was investigated in a reconstituted system to gain a better understanding of the effects of the mutations on the catalytic properties of these naturally occurring variants. All six variants were successfully overexpressed in Escherichia coli, including CYP2B6.8 (the K139E variant), which previously could not be overexpressed in mammalian COS-1 cells (J Pharmacol Exp Ther 311:34-43, 2004). The steady-state turnover rates for the hydroxylation of bupropion and efavirenz and the O-deethylation of 7-EFC showed that these mutations significantly alter the catalytic activities of CYP2B6. It was found that CYP2B6.6 exhibits 4- and 27-fold increases in the K(m) values for the hydroxylation of bupropion and efavirenz, respectively, and CYP2B6.8 completely loses its ability to metabolize any of the substrates under normal turnover conditions. However, compared with CYP2B6.1, CYP2B6.8 retains 77% of its 7-EFC O-deethylase activity in the presence of tert-butyl hydroperoxide as an alternative oxidant, indicating that the heme and the active site are catalytically competent. Presteady-state measurements of the rate of electron transfer from NADPH-dependent cytochrome P450 reductase (CPR) to CYP2B6.8 using stopped-flow spectrophotometry revealed that CYP2B6.8 is incapable of accepting electrons from CPR. These observations provide conclusive evidence suggesting that the charge-reversal mutation in the K139E variant prevents CYP2B6.8 from forming a functional complex with CPR. Results from this work provide further insights to better understand the genotype-phenotype correlation regarding CYP2B6 polymorphisms and drug metabolism.
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Affiliation(s)
- Haoming Zhang
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109-5632, USA
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Deenen MJ, Cats A, Beijnen JH, Schellens JHM. Part 2: pharmacogenetic variability in drug transport and phase I anticancer drug metabolism. Oncologist 2011; 16:820-34. [PMID: 21632461 DOI: 10.1634/theoncologist.2010-0259] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Equivalent drug doses in anticancer chemotherapy may lead to wide interpatient variability in drug response reflected by differences in treatment response or in severity of adverse drug reactions. Differences in the pharmacokinetic (PK) and pharmacodynamic (PD) behavior of a drug contribute to variation in treatment outcome among patients. An important factor responsible for this variability is genetic polymorphism in genes that are involved in PK/PD processes, including drug transporters, phase I and II metabolizing enzymes, and drug targets, and other genes that interfere with drug response. In order to achieve personalized pharmacotherapy, drug dosing and treatment selection based on genotype might help to increase treatment efficacy while reducing unnecessary toxicity. We present a series of four reviews about pharmacogenetic variability in anticancer drug treatment. This is the second review in the series and is focused on genetic variability in genes encoding drug transporters (ABCB1 and ABCG2) and phase I drug-metabolizing enzymes (CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, DPYD, CDA and BLMH) and their associations with anticancer drug treatment outcome. Based on the literature reviewed, opportunities for patient-tailored anticancer therapy are presented.
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Affiliation(s)
- Maarten J Deenen
- Division of Clinical Pharmacology, Department of Medical Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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Shankarkumar U, Shankarkumar A, Ghosh K. Human immunodeficiency virus therapeutics and pharmacogenomics. INDIAN JOURNAL OF HUMAN GENETICS 2011; 17 Suppl 1:S22-6. [PMID: 21747583 PMCID: PMC3125049 DOI: 10.4103/0971-6866.80354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Pharmacogenomics and pharmacogenetics are promising in development of a personalized treatment approach They are of paramount importance for basic immunology, for peptide based vaccine design (vaccinomics) drug monitoring in clinical setting and molecular pathophysiology of multifactorial diseases like cancer, tuberculosis, cardiac disorders, diabetes, asthma, HIV, etc.
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Affiliation(s)
- U. Shankarkumar
- National Institute of Immunohaematology, 13 floor, KEM Hospital, Parel, Mumbai, Maharashtra, India
| | - A. Shankarkumar
- National Institute of Immunohaematology, 13 floor, KEM Hospital, Parel, Mumbai, Maharashtra, India
| | - K. Ghosh
- National Institute of Immunohaematology, 13 floor, KEM Hospital, Parel, Mumbai, Maharashtra, India
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Chung JY, Cho JY, Lim HS, Kim JR, Yu KS, Lim KS, Shin SG, Jang IJ. Effects of pregnane X receptor (NR1I2) and CYP2B6 genetic polymorphisms on the induction of bupropion hydroxylation by rifampin. Drug Metab Dispos 2010; 39:92-7. [PMID: 20876786 DOI: 10.1124/dmd.110.035246] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We investigated genetic polymorphisms in the pregnane X receptor (NR1I2) in Korean individuals (n = 83) and the effects of NR1I2 genotypes on rifampin-mediated induction of bupropion hydroxylation. The pharmacokinetics of bupropion and hydroxybupropion were evaluated after an oral dose of bupropion (150 mg) administered before and after rifampin treatment for 7 days in 35 healthy subjects. The area under the time-concentration curve (AUC) ratio of hydroxybupropion to bupropion in CYP2B6*6 carriers was significantly lower than that in CYP2B6*6 noncarriers in both the basal and rifampin-induced states (p = 0.012). Among the CYP2B6*6 carriers (n = 13), the NR1I2 TGT (-25385T + g.7635G + g.8055T) carriers exhibited a significantly lower AUC ratio, representing the CYP2B6 hydroxylation activity, compared with the TGT noncarriers, in the induced state (11.9 versus 20.3, p = 0.045). The percent difference in the AUC ratio between the basal and induced states was also significantly different (212% versus 58.8%, p = 0.006). However, no significant difference was observed among the NR1I2 TGT genotypes for the CYP2B6*6 noncarriers (n = 22). In conclusion, it is suggested the NR1I2 TGT genotype decreases the bupropion hydroxylation induced by treatment with rifampin, particularly in CYP2B6*6 carriers.
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Affiliation(s)
- Jae Yong Chung
- Department of Pharmacology and Clinical Pharmacology, Yonsei University College of Medicine and Severance Hospital, Seoul, Korea
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Functional characterization of 26 CYP2B6 allelic variants (CYP2B6.2-CYP2B6.28, except CYP2B6.22). Pharmacogenet Genomics 2010; 20:459-62. [PMID: 20517174 DOI: 10.1097/fpc.0b013e32833bba0e] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cytochrome P450 2B6 (CYP2B6) is a potentially important enzyme for the metabolism of clinical drugs, and it exhibits genetic polymorphism. Thus far, 29 allelic variants of CYP2B6 (CYP2B6*1-CYP2B6*29) have been identified. This study aimed to investigate whether 26 of the variant alleles of CYP2B6 (CYP2B6*2-CYP2B6*21 and CYP2B6*23-CYP2B6*28) affect its kinetics in the metabolism of 7-ethoxy-4-trifluoromethylcoumarin (7-EFC) and selegiline. Wild-type CYP2B6.1 and the allelic variants were heterologously expressed in COS-7 cells. In-vitro kinetic analysis revealed that when compared with the wild-type protein CYP2B6.1, CYP2B6.10 and CYP2B6.14 exhibited significantly lower V(max)/K(m) values for selegiline N-demethylation. The kinetic parameters of CYP2B6.8, CYP2B6.11, CYP2B6.12, CYP2B6.13, CYP2B6.15, CYP2B6.18, CYP2B6.21, CYP2B6.24, and CYP2B6.28 could not be determined because these enzymes were inactive in the deethylation of 7-EFC and the N-demethylation/N-depropagylation of selegiline. These findings provide useful information for further genotype-phenotype studies on interindividual differences in the metabolism of CYP2B6 substrate drugs.
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Lu X, Hora B, Cai F, Gao F. Generation of random mutant libraries with multiple primers in a single reaction. J Virol Methods 2010; 167:146-51. [PMID: 20362002 DOI: 10.1016/j.jviromet.2010.03.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 11/26/2022]
Abstract
Characterization of multiple sites in a single gene that are important in biological phenotypes is challenging due to the difficulty to generate many mutants representing all or a majority of combinations of mutations in the gene. Using the HIV-1 env and pol genes as templates, four random libraries were generated representing different combinations of mutations introduced by up to 36 mutagenesis primers in a single assay. Over 86% of the clones contained mutations and the mutants tended to have single or fewer mutations in the libraries. When protein size was used as a screening marker, all identified clones contained at least 2 mutations and up to 12 mutations were detected in a single clone. Nearly all mutant clones in each library contained unique mutations, indicating that mutants in the library were generated at random. Closely related mutations which were overlapped by neighboring mutagenesis primers were often introduced in this system. Analysis of the env library showed that some potential N-linked glycosylation sites did not increase the Env molecular mass significantly, suggesting they were not used for glycosylation or only limited carbohydrate moieties were added at these sites. This novel method can serve as a powerful tool to study the biological phenotypes of genes whose functions are determined by multiple sites.
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Affiliation(s)
- Xiaozhi Lu
- Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
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