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Abstract
BACKGROUND UGT1A4 is primarily expressed in the liver and exhibits catalytic activities for various drugs. Amongst the few UGT1A4 polymorphisms evaluated, studies support the alteration of UGT1A4-mediated glucuronidation by a few variations including the Pro²⁴Thr and Leu⁴⁸Val variants (referred to as UGT1A4*2 and *3). METHODS We therefore investigated genetic mechanisms that might contribute to interindividual variation in UGT1A4 expression and activity. The UGT1A4 gene was sequenced from -4963 bp relative to the ATG to 2000 bp after the first exon in 184 unrelated Caucasians and African-Americans. RESULTS We identified a large number of genetic variations, including 13 intronic, 39 promoter, as well as 14 exonic polymorphisms, with 10 that lead to amino-acid changes. Of the nucleotide variations found in the -5 kb promoter region, five are located in the proximal region (first 500 bp), and positioned in putative HNF-1 and OCT-1 binding sites. Four of these variants, placed at -163, -219, -419 and -463, are in complete linkage disequilibrium with the Leu⁴⁸Val coding region variant and with several variants in the upstream region of the promoter. Transient transfections of reference and variant promoter constructs (from position -500 to +1) in different cell lines with or without co-expression of HNF-1 and/or OCT-1 showed limited effect of these variations. CONCLUSION Additional functional studies on promoter variants are still required to predict their potential influence on UGT1A4 expression in vivo. Besides, several coding variants significantly modified the enzyme kinetics for tamoxifen and Z-4-hydroxytamoxifen (Val⁴⁸, Asp⁵⁰, Gln⁵⁶, Phe¹⁷⁶, Asn²⁵⁰, Leu²⁷⁶) and are expected to have a potential in vivo effect.
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Wu B, Wang X, Zhang S, Hu M. Accurate prediction of glucuronidation of structurally diverse phenolics by human UGT1A9 using combined experimental and in silico approaches. Pharm Res 2012; 29:1544-61. [PMID: 22302521 DOI: 10.1007/s11095-012-0666-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 01/03/2012] [Indexed: 11/26/2022]
Abstract
PURPOSE Catalytic selectivity of human UGT1A9, an important membrane-bound enzyme catalyzing glucuronidation of xenobiotics, was determined experimentally using 145 phenolics and analyzed by 3D-QSAR methods. METHODS Catalytic efficiency of UGT1A9 was determined by kinetic profiling. Quantitative structure activity relationships were analyzed using CoMFA and CoMSIA techniques. Molecular alignment of substrate structures was made by superimposing the glucuronidation site and its adjacent aromatic ring to achieve maximal steric overlap. For a substrate with multiple active glucuronidation sites, each site was considered a separate substrate. RESULTS 3D-QSAR analyses produced statistically reliable models with good predictive power (CoMFA: q2 = 0.548, r2 = 0.949, r pred 2 = 0.775; CoMSIA: q2 = 0.579, r2 = 0.876, r pred 2 = 0.700). Contour coefficient maps were applied to elucidate structural features among substrates that are responsible for selectivity differences. Contour coefficient maps were overlaid in the catalytic pocket of a homology model of UGT1A9, enabling identification of the UGT1A9 catalytic pocket with a high degree of confidence. CONCLUSION CoMFA/CoMSIA models can predict substrate selectivity and in vitro clearance of UGT1A9. Our findings also provide a possible molecular basis for understanding UGT1A9 functions and substrate selectivity.
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Affiliation(s)
- Baojian Wu
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, 1441 Moursund St., Houston, Texas 77030, USA
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Boudou-Rouquette P, Narjoz C, Golmard JL, Thomas-Schoemann A, Mir O, Taieb F, Durand JP, Coriat R, Dauphin A, Vidal M, Tod M, Loriot MA, Goldwasser F, Blanchet B. Early sorafenib-induced toxicity is associated with drug exposure and UGTIA9 genetic polymorphism in patients with solid tumors: a preliminary study. PLoS One 2012; 7:e42875. [PMID: 22912756 PMCID: PMC3418266 DOI: 10.1371/journal.pone.0042875] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/13/2012] [Indexed: 12/21/2022] Open
Abstract
Background Identifying predictive biomarkers of drug response is of key importance to improve therapy management and drug selection in cancer therapy. To date, the influence of drug exposure and pharmacogenetic variants on sorafenib-induced toxicity remains poorly documented. The aim of this pharmacokinetic/pharmacodynamic (PK/PD) study was to investigate the relationship between early toxicity and drug exposure or pharmacogenetic variants in unselected adult outpatients treated with single-agent sorafenib for advanced solid tumors. Methods Toxicity was recorded in 54 patients on days 15 and 30 after treatment initiation and sorafenib exposure was assessed in 51 patients. The influence of polymorphisms in CYP3A5, UGT1A9, ABCB1 and ABCG2 was examined in relation to sorafenib exposure and toxicity. Clinical characteristics, drug exposure and pharmacogenetic variants were tested univariately for association with toxicities. Candidate variables with p<0.1 were analyzed in a multivariate analysis. Results Gender was the sole parameter independently associated with sorafenib exposure (p = 0.0008). Multivariate analysis showed that increased cumulated sorafenib (AUCcum) was independently associated with any grade ≥3 toxicity (p = 0.037); UGT1A9 polymorphism (rs17868320) with grade ≥2 diarrhea (p = 0.015) and female gender with grade ≥2 hand-foot skin reaction (p = 0.018). Using ROC curve, the threshold AUCcum value of 3,161 mg/L.h was associated with the highest risk to develop any grade ≥3 toxicity (p = 0.018). Conclusion In this preliminary study, increased cumulated drug exposure and UGT1A9 polymorphism (rs17868320) identified patients at high risk for early sorafenib-induced severe toxicity. Further PK/PD studies on larger population are warranted to confirm these preliminary results.
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Affiliation(s)
- Pascaline Boudou-Rouquette
- Centre d'étude et de recours sur les inhibiteurs de l'angiogénèse, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité de Cancérologie médicale, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Céline Narjoz
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Biochimie, Unité Fonctionnelle de Pharmacogénétique et Oncologie Moléculaire, Paris, France
- Université Paris Descartes, INSERM UMR-S 775, Paris, France
| | - Jean Louis Golmard
- Assistance Publique Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Département de Biostatistiques, Paris, France
| | - Audrey Thomas-Schoemann
- Centre d'étude et de recours sur les inhibiteurs de l'angiogénèse, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité Fonctionnelle de Pharmacocinétique et Pharmacochimie, Paris, France
- UMR8638 CNRS, UFR de Pharmacie, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Olivier Mir
- Centre d'étude et de recours sur les inhibiteurs de l'angiogénèse, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité de Cancérologie médicale, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Fabrice Taieb
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité Fonctionnelle de Pharmacocinétique et Pharmacochimie, Paris, France
| | - Jean-Philippe Durand
- Centre d'étude et de recours sur les inhibiteurs de l'angiogénèse, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité de Cancérologie médicale, Paris, France
| | - Romain Coriat
- Centre d'étude et de recours sur les inhibiteurs de l'angiogénèse, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité de Cancérologie médicale, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Alain Dauphin
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité Fonctionnelle de Pharmacocinétique et Pharmacochimie, Paris, France
| | - Michel Vidal
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité Fonctionnelle de Pharmacocinétique et Pharmacochimie, Paris, France
- UMR8638 CNRS, UFR de Pharmacie, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Michel Tod
- Pharmacie, Hôpital de la Croix-Rousse, Hospices civils de Lyon, Lyon, France
- EMR3738, Université de Lyon, Lyon, France
| | - Marie-Anne Loriot
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Biochimie, Unité Fonctionnelle de Pharmacogénétique et Oncologie Moléculaire, Paris, France
- Université Paris Descartes, INSERM UMR-S 775, Paris, France
| | - François Goldwasser
- Centre d'étude et de recours sur les inhibiteurs de l'angiogénèse, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité de Cancérologie médicale, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Benoit Blanchet
- Centre d'étude et de recours sur les inhibiteurs de l'angiogénèse, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Unité Fonctionnelle de Pharmacocinétique et Pharmacochimie, Paris, France
- * E-mail:
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Chatzistefanidis D, Georgiou I, Kyritsis AP, Markoula S. Functional impact and prevalence of polymorphisms involved in the hepatic glucuronidation of valproic acid. Pharmacogenomics 2012; 13:1055-71. [DOI: 10.2217/pgs.12.78] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metabolism of valproic acid, a widely used drug, is only partially understood. It is mainly metabolized through glucuronidation and acts as a substrate for various UDP-glucuronosyltransferases (UGTs). UGTs metabolizing valproic acid in the liver are UGT1A3, UGT1A4, UGT1A6, UGT1A9 and UGT2B7, with UGT1A6 and UGT2B7 being the most prominent. Polymorphisms in genes expressing these enzymes may have clinical consequences, regarding dosing, blood levels of the drug and adverse reactions. Not all genes are well studied and studies, where they exist, report conflicting results. Prevalence of polymorphisms and various haplotypes is also of great importance, as it may suggest different therapeutic approaches in various populations. Presented here is a review of currently known polymorphisms, their functional impact, when known, and their prevalence in different populations, highlighting the current state of understanding and areas where there is a lack of data and suggesting new perspectives for further research.
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Affiliation(s)
| | - Ioannis Georgiou
- Medical Genetics & Assisted Reproduction, Medical School, University of Ioannina, Ioannina, Greece
| | | | - Sofia Markoula
- Department of Neurology, Medical School, University of Ioannina, Ioannina, Greece
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Zhang X, Ao G, Wang Y, Yan W, Wang M, Chen E, Yang F, Yang J. Genetic variants and haplotypes of the UGT1A9, 1A7 and 1A1 genes in Chinese Han. Genet Mol Biol 2012; 35:428-34. [PMID: 22888291 PMCID: PMC3389530 DOI: 10.1590/s1415-47572012005000036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/26/2012] [Indexed: 11/22/2022] Open
Abstract
In this report, we describe combined polymorphisms of the UGT1A9, UGT1A7 and UGT1A1 genes in 100 unrelated, healthy Chinese Han subjects. The functional regions of these genes were sequenced and comprehensively analyzed for genetic polymorphisms. Thirty variants were detected, including five novel forms. Tentative functional predictions indicated that a Cys → Arg substitution at position 277 in the UGT1A7 gene could alter the protein conformation and that 12460T > G in the 3′UTR might influence protein translation through specifically expressed miRNAs. UGT1A9*1b was a major functional variant in the subjects examined whereas the *1f allele had a frequency of only 0.5%. A special functional haplotype (GAGAAC) was identified for UGT1A9, 1A7 and 1A1. These findings provide fundamental genetic information that may serve as a basis for larger studies designed to assess the metabolic phenotypes associated with UGT1A polymorphisms. They also provide important data for the implementation of personalized medicine in Chinese Han.
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Affiliation(s)
- Xiaoqing Zhang
- National Engineering Research Center for Miniaturized Detection System, College of Life Sciences, Northwest University, Xi'an, Shaanxi, China
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Ferrari M, Martignoni E, Blandini F, Riboldazzi G, Bono G, Marino F, Cosentino M. Association of UDP-glucuronosyltransferase 1A9 polymorphisms with adverse reactions to catechol-O-methyltransferase inhibitors in Parkinson's disease patients. Eur J Clin Pharmacol 2012; 68:1493-9. [PMID: 22527346 DOI: 10.1007/s00228-012-1281-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 03/19/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE To investigate the association between adverse reactions to catechol-O-methyltransferase (COMT) inhibitors and the UDP-glucuronosyltransferase 1A9 genotypes UGT1A9*1b and UGT1A9*3a, which were previously identified in individual cases of COMT inhibitor-induced toxicity. METHODS The study included 52 Parkinson's disease (PD) patients on COMT inhibitors without evidence of adverse reactions and 11 PD patients who had been withdrawn from COMT inhibitors due to adverse reactions. UGT1A9*1b was identified by direct sequencing of the PCR amplification of the gene and UGT1A9*3a was assayed by real-time PCR. RESULTS The frequency of the *3a/*3a and *1/*3a genotype variants was 45.5 % in subjects with adverse reactions and 21.1 % in subjects without adverse reactions [overall UGT1A9*3a allele frequency 27.3 vs. 11.5 %, P = 0.087; odds ratio (OR) 2.87, 95 % confidence interval (CI) 0.94-8.77]. The frequency of genotype combinations leading to low glucuronosyltransferase activity (*3a/*3a irrespective of *1b or *1/*3a and *1/*1b) was 5.8 % in subjects without adverse reactions and 36.4 % in subjects with adverse reactions (P = 0.014; OR 9.33, 95 % CI 1.71-50.78). CONCLUSIONS In PD patients UDP-glucuronosyltransferase 1A9 genotypes are associated with adverse reactions to COMT inhibitors, leading to treatment withdrawal. UDP-glucuronosyltransferase 1A9 genotyping may be a screening and/or diagnostic test to assist individualized treatments with COMT inhibitors.
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Affiliation(s)
- Marco Ferrari
- Center for Research in Medical Pharmacology, University of Insubria, Via Ottorino Rossi n. 9, 21100, Varese, VA, Italy
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Miyagi SJ, Milne AM, Coughtrie MWH, Collier AC. Neonatal development of hepatic UGT1A9: implications of pediatric pharmacokinetics. Drug Metab Dispos 2012; 40:1321-7. [PMID: 22492655 DOI: 10.1124/dmd.111.043752] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This article reports on the development of UDP-glucuronosyltransferase 1A9 (UGT1A9) in neonatal and pediatric liver. The substrate 4-methylumbelliferone (4MU) with specific inhibition by niflumic acid was used to define specific UGT1A9 activity. Subsequently, in silico pharmacokinetic (PK) and physiology-based pharmacokinetic (PBPK) modeling was used to determine UGT1A9 maturation and hepatic clearance. Modeled maximal enzyme activity was 27.9 nmol · min(-1) · mg protein(-1) at 4 months of age, which had high concordance with the average V(max) in 45 individual adult (>20 years) livers of 29.0 nmol · min(-1) · mg protein(-1). The activity of UGT1A9 ranged 7.5-fold in the adult population (4.1-54.5 nmol · min(-1) · mg protein(-1)). Expression of UGT1A9 correlated with age only in children younger than 1 year (Spearman r = 0.70). Activity correlated with expression up to 18 years of age (Spearman r = 0.76). Furthermore, scaling intrinsic hepatic clearance of 4MU with an allometric PK model yielded a high clearance at birth and then fell to adult levels (1.3 l · h(-1) · kg(-1) at 18.1 years for well stirred or 1.4 l · h(-1) · kg(-1) at 18.7 years for parallel tube). The Simcyp PBPK models did not converge but showed an increase in clearance at under 1 year of age and then decreased to adult levels at approximately 20 years of age. Allometric scaling may be more accurate in cases of high-extraction drugs. Enzyme activities or hepatic clearances did not differ with gender or ethnicity. The UGT1A9 isoform has higher normalized clearance for 4MU at young ages, which may explain how other UGT1A9 substrates, such as propofol, have higher clearances in children than in adults.
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Affiliation(s)
- Shogo J Miyagi
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Mānoa, 651 Ilalo St., BSB 320, Honolulu, HI 96813, USA
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Population pharmacokinetic analysis and pharmacogenetics of raltegravir in HIV-positive and healthy individuals. Antimicrob Agents Chemother 2012; 56:2959-66. [PMID: 22371894 DOI: 10.1128/aac.05424-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The objectives of this study were to characterize raltegravir (RAL) population pharmacokinetics in HIV-positive (HIV(+)) and healthy individuals, identify influential factors, and search for new candidate genes involved in UDP glucuronosyltransferase (UGT)-mediated glucuronidation. The pharmacokinetic analysis was performed with NONMEM. Genetic association analysis was performed with PLINK using the relative bioavailability as the phenotype. Simulations were performed to compare once- and twice-daily regimens. A 2-compartment model with first-order absorption adequately described the data. Atazanavir, gender, and bilirubin levels influenced RAL relative bioavailability, which was 30% lower in HIV(+) than in healthy individuals. UGT1A9*3 was the only genetic variant possibly influencing RAL pharmacokinetics. The majority of RAL pharmacokinetic variability remains unexplained by genetic and nongenetic factors. Owing to the very large variability, trough drug levels might be very low under the standard dosing regimen, raising the question of a potential relevance of therapeutic drug monitoring of RAL in some situations.
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Wells AF, MacDonald PA, Chefo S, Jackson RL. African American patients with gout: efficacy and safety of febuxostat vs allopurinol. BMC Musculoskelet Disord 2012; 13:15. [PMID: 22316106 PMCID: PMC3317813 DOI: 10.1186/1471-2474-13-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 02/09/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND African Americans are twice as likely as Caucasians to develop gout, but they are less likely to be treated with urate-lowering therapy (ULT). Furthermore, African Americans typically present with more comorbidities associated with gout, such as hypertension, obesity, and renal impairment. We determined the efficacy and safety of ULT with febuxostat or allopurinol in African American subjects with gout and associated comorbidities and in comparison to Caucasian gout subjects. METHODS This is a secondary analysis of the 6-month Phase 3 CONFIRMS trial. Eligible gouty subjects with baseline serum urate (sUA) ≥ 8.0 mg/dL were randomized 1:1:1 to receive febuxostat 40 mg, febuxostat 80 mg, or allopurinol (300 mg or 200 mg depending on renal function) daily. All subjects received gout flare prophylaxis. Primary efficacy endpoint was the proportion of subjects in each treatment group with sUA < 6.0 mg/dL at the final visit. Additional endpoints included the proportion of subjects with mild or with moderate renal impairment who achieved a target sUA < 6.0 mg/dL at final visit. Adverse events (AEs) were recorded throughout the study. RESULTS Of the 2,269 subjects enrolled, 10.0% were African American and 82.1% were Caucasian. African American subjects were mostly male (89.5%), obese (BMI ≥ 30 kg/m2; 67.1%), with mean baseline sUA of 9.8 mg/dL and mean duration of gout of 10.4 years. The proportions of African American subjects with a baseline history of diabetes, renal impairment, or cardiovascular disease were significantly higher compared to Caucasians (p < 0.001). ULT with febuxostat 80 mg was superior to both febuxostat 40 mg (p < 0.001) and allopurinol (p = 0.004). Febuxostat 40 mg was comparable in efficacy to allopurinol. Significantly more African American subjects with mild or moderate renal impairment achieved sUA < 6.0 mg/dL in the febuxostat 80 group than in either the febuxostat 40 mg or allopurinol group (p < 0.05). Efficacy rates in all treatment groups regardless of renal function were comparable between African American and Caucasian subjects, as were AE rates. CONCLUSIONS In African American subjects with significant comorbidities, febuxostat 80 mg is significantly more efficacious than either febuxostat 40 mg or allopurinol 200/300 mg. Febuxostat was well tolerated in this African American population.Please see related article: http://www.biomedcentral.com/1741-7015/10/15.
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Affiliation(s)
- Alvin F Wells
- Rheumatology and Immunotherapy Center, 4225 W Oakwood Park Court, Franklin, WI 53132, USA.
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The influence of UGT polymorphisms as biomarkers in solid organ transplantation. Clin Chim Acta 2012; 413:1318-25. [PMID: 22327003 DOI: 10.1016/j.cca.2012.01.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 01/20/2012] [Accepted: 01/25/2012] [Indexed: 12/18/2022]
Abstract
In solid organ transplant patients, it is important to maintain a fine balance between preventing rejection and reducing adverse effects. Several immunosuppressive agents such tacrolimus, cyclosporine, sirolimus and everolimus require therapeutic drug monitoring. The study of germline variation of the genome has opened novel opportunities to individualize therapy. Among the currently available immunosuppressive agents, cyclosporine, tacrolimus and mycophenolic acid are in vitro substrates of the UGT1A and 2B families of glucuronidation enzymes. Mycophenolic acid, either given as mycophenolate mofetil or mycophenolate sodium, is the most frequently used antiproliferative immunosuppressant. Mycophenolic acid is a prodrug which is rapidly de-esterified in the gut wall, blood, liver and tissue to the active moiety, mycophenolic acid (MPA). MPA undergoes significant hepatic metabolism to several metabolites. The 7-hydroxyglucuronide MPA is the major metabolite and is inactive. This paper reviews the current status of the genetic associations between germline UGT variants and the pharmacokinetics and pharmacodynamics of mycophenolic acid. Our conclusive assessment of the studies conducted so far is that these germline markers are not ready to be used in the clinic to individualize mycophenolic acid dosing and improve outcome. Novel approaches are required to identify new genetic determinants of outcomes in transplantation.
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Harbourt DE, Fallon JK, Ito S, Baba T, Ritter JK, Glish GL, Smith PC. Quantification of human uridine-diphosphate glucuronosyl transferase 1A isoforms in liver, intestine, and kidney using nanobore liquid chromatography-tandem mass spectrometry. Anal Chem 2011; 84:98-105. [PMID: 22050083 DOI: 10.1021/ac201704a] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Uridine-disphosphate glucuronosyl transferase (UGT) enzymes catalyze the formation of glucuronide conjugates of phase II metabolism. Methods for absolute quantification of UGT1A1 and UGT1A6 were previously established utilizing stable isotope peptide internal standards with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The current method expands upon this by quantifying eight UGT1A isoforms by nanobore high-performance liquid chromatography (HPLC) coupled with a linear ion trap time-of-flight mass spectrometer platform. Recombinant enzyme digests of each of the isoforms were used to determine assay linearity and detection limits. Enzyme expression level in human liver, kidney, and intestinal microsomal protein was determined by extrapolation from spiked stable isotope standards. Intraday and interday variability was <25% for each of the enzyme isoforms. Enzyme expression varied from 3 to 96 pmol/mg protein in liver and intestinal microsomal protein digests. Expression levels of UGT1A7, 1A8, and 1A10 were below detection limits (<1 pmol/mg protein) in human liver microsome (HLMs). In kidney microsomes the expression of UGT1A3 was below detection limits, but levels of UGT1A4, 1A7, 1A9, and 1A10 protein were higher relative to that of liver, suggesting that renal glucuronidation could be a significant factor in renal elimination of glucuronide conjugates. This novel method allows quantification of all nine UGT1A isoforms, many previously not amenable to measurement with traditional methods such as immunologically based assays. Quantitative measurement of proteins involved in drug disposition, such as the UGTs, significantly improves the ability to evaluate and interpret in vitro and in vivo studies in drug development.
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Affiliation(s)
- David E Harbourt
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina 27599, USA
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Wang H, Yuan L, Zeng S. Characterizing the effect of UDP-glucuronosyltransferase (UGT) 2B7 and UGT1A9 genetic polymorphisms on enantioselective glucuronidation of flurbiprofen. Biochem Pharmacol 2011; 82:1757-63. [DOI: 10.1016/j.bcp.2011.08.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/16/2011] [Accepted: 08/04/2011] [Indexed: 10/17/2022]
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Piedade R, Gil JP. The pharmacogenetics of antimalaria artemisinin combination therapy. Expert Opin Drug Metab Toxicol 2011; 7:1185-200. [PMID: 21899476 DOI: 10.1517/17425255.2011.608660] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Plasmodium falciparum malaria is one of the world's most lethal infectious diseases, commanding millions of drug administrations per year. The pharmacogenetics of these drugs is poorly known, although its application can be pivotal for the optimized management of this disease. AREAS COVERED The main components of artemisinin combination therapy (ACT), the worldwide main antimalarial strategy, are metabolized by the polymorphic CYP3A4 (mefloquine, artemether, lumefantrine), CYP2C8 (amodiaquine), CYP2A6 (artesunate) and CYP1A1/2 (amodiaquine/desethylamodiaquine), with dihydroartemisinin being acted by Phase II UDP-glucuronosyltransferases. The worldwide adoption of ACT is leading to a large number of antimalarial treatments. Simultaneously, the feared development of parasite drug resistance might drive dosing increases. In these scenarios of increased drug exposure, pharmacogenetics can be a key tool supporting evidence-based medicine aiming for the longest possible useful lifespan of this important chemotherapy. EXPERT OPINION Translation in this moment is not operationally possible at an individual level, but large population studies are achievable for: i) the development of robust pharmacogenetics markers; and ii) the parallel development of a pharmacogenetic cartography of malaria settings. Advances in the understanding of antimalarial pharmacogenetics are urgent in order to protect the exposed populations, enhance the effectiveness of ACT and, consequently, contributing for the long aimed elimination of the disease.
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Affiliation(s)
- Rita Piedade
- Karolinska Institute, Division of Pharmacogenetics, Department of Physiology and Pharmacology, Stockholm, Sweden
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Jain L, Woo S, Gardner ER, Dahut WL, Kohn EC, Kummar S, Mould DR, Giaccone G, Yarchoan R, Venitz J, Figg WD. Population pharmacokinetic analysis of sorafenib in patients with solid tumours. Br J Clin Pharmacol 2011; 72:294-305. [PMID: 21392074 PMCID: PMC3162659 DOI: 10.1111/j.1365-2125.2011.03963.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 03/06/2011] [Indexed: 12/28/2022] Open
Abstract
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Sorafenib is a multikinase inhibitor with activity against B-raf, C-raf, VEGFR2, PDGFRβ and FGFR1. Sorafenib is clinically approved for the treatment of renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC). The pharmacokinetics (PK) of sorafenib are highly variable between subjects. Sorafenib exposure increases less than dose proportionally (likely due to limited solubility). Sorafenib undergoes enterohepatic recycling (EHC). WHAT THIS STUDY ADDS This is the first study to characterize the PK of sorafenib using a model based on sorafenib's known disposition characteristics such as delayed/solubility-limited GI absorption and EHC. The parameterization of the EHC model used a square wave function to describe the gall bladder emptying. This study evaluated the effect of baseline bodyweight, BSA, age, gender, liver function parameters, kidney function parameters and genotype with respect to CYP3A4*1B, CYP3A5*3C, UGT1A9*3 and UGT1A9*5 on sorafenib PK. No clinically important covariates were identified. This model can be used to simulate and explore alternative dosing regimens and to develop exposure-response relationships for sorafenib. AIMS To characterize the pharmacokinetics (PK) of sorafenib in patients with solid tumours and to evaluate the possible effects of demographic, clinical and pharmacogenetic (CYP3A4*1B, CYP3A5*3C, UGT1A9*3 and UGT1A9*5) covariates on the disposition of sorafenib. METHODS PK were assessed in 111 patients enrolled in five phase I and II clinical trials, where sorafenib 200 or 400 mg was administered twice daily as a single agent or in combination therapy. All patients were genotyped for polymorphisms in metabolic enzymes for sorafenib. Population PK analysis was performed by using nonlinear mixed effects modelling (NONMEM). The final model was validated using visual predictive checks and nonparametric bootstrap analysis. RESULTS A one compartment model with four transit absorption compartments and enterohepatic circulation (EHC) adequately described sorafenib disposition. Baseline bodyweight was a statistically significant covariate for distributional volume, accounting for 4% of inter-individual variability (IIV). PK model parameter estimates (range) for an 80 kg patient were clearance 8.13 l h(-1) (3.6-22.3 l h(-1) ), volume 213 l (50-1000 l), mean absorption transit time 1.98 h (0.5-13 h), fraction undergoing EHC 50% and average time to gall bladder emptying 6.13 h. CONCLUSIONS Overall, population PK analysis was consistent with known biopharmaceutical/PK characteristics of oral sorafenib. No clinically important PK covariates were identified.
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Affiliation(s)
- Lokesh Jain
- Clinical Pharmacology Program Medical Oncology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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Deenen MJ, Cats A, Beijnen JH, Schellens JHM. Part 3: Pharmacogenetic variability in phase II anticancer drug metabolism. Oncologist 2011; 16:992-1005. [PMID: 21659608 DOI: 10.1634/theoncologist.2010-0260] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Equivalent drug doses may lead to wide interpatient variability in drug response to anticancer therapy. Known determinants that may affect the pharmacological response to a drug are, among others, nongenetic factors, including age, gender, use of comedication, and liver and renal function. Nonetheless, these covariates do not explain all the observed interpatient variability. Differences in genetic constitution among patients have been identified to be important factors that contribute to differences in drug response. Because genetic polymorphism may affect the expression and activity of proteins encoded, it is a key covariate that is responsible for variability in drug metabolism, drug transport, and pharmacodynamic drug effects. We present a series of four reviews about pharmacogenetic variability. This third part in the series of reviews is focused on genetic variability in phase II drug-metabolizing enzymes (glutathione S-transferases, uridine diphosphoglucuronosyl transferases, methyltransferases, sulfotransferases, and N-acetyltransferases) and discusses the effects of genetic polymorphism within the genes encoding these enzymes on anticancer drug therapy outcome. Based on the literature reviewed, opportunities for patient-tailored anticancer therapy are proposed.
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Affiliation(s)
- Maarten J Deenen
- The Netherlands Cancer Institute, Department of Medical Oncology, Amsterdam, The Netherlands
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66
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Bellanti F, Kågedal B, Della Pasqua O. Do pharmacokinetic polymorphisms explain treatment failure in high-risk patients with neuroblastoma? Eur J Clin Pharmacol 2011; 67 Suppl 1:87-107. [PMID: 21287160 PMCID: PMC3112027 DOI: 10.1007/s00228-010-0966-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Accepted: 11/27/2010] [Indexed: 12/30/2022]
Abstract
PURPOSE Neuroblastoma is the most common extracranial solid tumour in childhood. It accounts for 15% of all paediatric oncology deaths. In the last few decades, improvement in treatment outcome for high-risk patients has not occurred, with an overall survival rate <30-40%. Many reasons may account for such a low survival rate. The aim of this review is to evaluate whether pharmacogenetic factors can explain treatment failure in neuroblastoma. METHODS A literature search based on PubMed's database Medical Subject Headings (MeSH) was performed to retrieve all pertinent publications on current treatment options and new classes of drugs under investigation. One hundred and fifty-eight articles wer reviewed, and relevant data were extracted and summarised. RESULTS AND CONCLUSIONS Few of the large number of polymorphisms identified thus far showed an effect on pharmacokinetics that could be considered clinically relevant. Despite their clinical relevance, none of the single nucleotide polymorphisms (SNPs) investigated can explain treatment failure. These findings seem to reflect the clinical context in which anti-tumour drugs are used, i.e. in combination with multimodal therapy. In addition, many pharmacogenetic studies did not assess (differences in) drug exposure, which could contribute to explaining pharmacogenetic associations. Furthermore, it remains unclear whether the significant activity of new drugs on different neuroblastoma cell lines translates into clinical efficacy, irrespective of resistance or myelocytomatosis viral related oncogene, neuroblastoma derived (MYCN) amplification. Elucidation of the clinical role of pharmacogenetic factors in the treatment of neuroblastoma demands an integrated pharmacokinetic-pharmacodynamic approach to the analysis of treatment response data.
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Affiliation(s)
- Francesco Bellanti
- Division of Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden, The Netherlands
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67
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Li X, Shang L, Wu Y, Abbas S, Li D, Netter P, Ouzzine M, Wang H, Magdalou J. Identification of the Human UDP-glucuronosyltransferase Isoforms Involved in the Glucuronidation of the Phytochemical Ferulic Acid. Drug Metab Pharmacokinet 2011; 26:341-50. [DOI: 10.2133/dmpk.dmpk-10-rg-125] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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68
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Polymorphisms of UGT1A7 and XRCC1 are associated with an increased risk of hepatocellular carcinoma in Northeast China. Chin J Cancer Res 2010. [DOI: 10.1007/s11670-010-0260-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
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Flavopiridol pharmacogenetics: clinical and functional evidence for the role of SLCO1B1/OATP1B1 in flavopiridol disposition. PLoS One 2010; 5:e13792. [PMID: 21072184 PMCID: PMC2967470 DOI: 10.1371/journal.pone.0013792] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 09/27/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Flavopiridol is a cyclin-dependent kinase inhibitor in phase II clinical development for treatment of various forms of cancer. When administered with a pharmacokinetically (PK)-directed dosing schedule, flavopiridol exhibited striking activity in patients with refractory chronic lymphocytic leukemia. This study aimed to evaluate pharmacogenetic factors associated with inter-individual variability in pharmacokinetics and outcomes associated with flavopiridol therapy. METHODOLOGY/PRINCIPAL FINDINGS Thirty-five patients who received single-agent flavopiridol via the PK-directed schedule were genotyped for 189 polymorphisms in genes encoding 56 drug metabolizing enzymes and transporters. Genotypes were evaluated in univariate and multivariate analyses as covariates in a population PK model. Transport of flavopiridol and its glucuronide metabolite was evaluated in uptake assays in HEK-293 and MDCK-II cells transiently transfected with SLCO1B1. Polymorphisms in ABCC2, ABCG2, UGT1A1, UGT1A9, and SLCO1B1 were found to significantly correlate with flavopiridol PK in univariate analysis. Transport assay results indicated both flavopiridol and flavopiridol-glucuronide are substrates of the SLCO1B1/OATP1B1 transporter. Covariates incorporated into the final population PK model included bilirubin, SLCO1B1 rs11045819 and ABCC2 rs8187710. Associations were also observed between genotype and response. To validate these findings, a second set of data with 51 patients was evaluated, and overall trends for associations between PK and PGx were found to be consistent. CONCLUSIONS/SIGNIFICANCE Polymorphisms in transport genes were found to be associated with flavopiridol disposition and outcomes. Observed clinical associations with SLCO1B1 were functionally validated indicating for the first time its relevance as a transporter of flavopiridol and its glucuronide metabolite. A second 51-patient dataset indicated similar trends between genotype in the SLCO1B1 and other candidate genes, thus providing support for these findings. Further study in larger patient populations will be necessary to fully characterize and validate the clinical impact of polymorphisms in SLCO1B1 and other transporter and metabolizing enzyme genes on outcomes from flavopiridol therapy.
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Heydel JM, Holsztynska EJ, Legendre A, Thiebaud N, Artur Y, Le Bon AM. UDP-glucuronosyltransferases (UGTs) in neuro-olfactory tissues: expression, regulation, and function. Drug Metab Rev 2010; 42:74-97. [PMID: 20067364 DOI: 10.3109/03602530903208363] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This work aims to review uridine diphosphate (UDP)-glucuronosyltransferase (UGT) expression and activities along different neuronal structures involved in the common physiological process of olfaction: olfactory epithelium, olfactory bulb, and olfactory cortex. For the first time, using high-throughput in situ hybridization data generated by the Allen Brain Atlas (ABA), we present quantitative analysis of spatial distribution of UGT genes in the mouse brain. The olfactory area is a central nervous system site with the highest expression of UGTs, including UGT isoforms not previously identified in the brain. Since there is evidence of the transfer of xenobiotics to the brain through the nasal pathway, circumventing the blood-brain barrier, olfactory UGTs doubtlessly share the common function of detoxification, but they are also involved in the metabolism and turnover of exogenous or endogenous compounds critical for physiological olfactory processing in these tissues. The function of olfactory UGTs will be discussed with a special focus on their participation in the perireceptor events involved in the modulation of olfactory perception.
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71
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Ramírez J, Ratain MJ, Innocenti F. Uridine 5'-diphospho-glucuronosyltransferase genetic polymorphisms and response to cancer chemotherapy. Future Oncol 2010; 6:563-85. [PMID: 20373870 PMCID: PMC3102300 DOI: 10.2217/fon.10.17] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Pharmacogenetics aims to elucidate how genetic variation affects the efficacy and side effects of drugs, with the ultimate goal of personalizing medicine. Clinical studies of the genetic variation in the uridine 5'-diphosphoglucuronosyltransferase gene have demonstrated how reduced-function allele variants can predict the risk of severe toxicity and help identify cancer patients who could benefit from reduced-dose schedules or alternative chemotherapy. Candidate polymorphisms have also been identified in vitro, although the functional consequences of these variants still need to be tested in the clinical setting. Future approaches in uridine 5'-diphosphoglucuronosyltransferase pharmacogenetics include genetic testing prior to drug treatment, genotype-directed dose-escalation studies, study of genetic variation at the haplotype level and genome-wide studies.
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Affiliation(s)
- Jacqueline Ramírez
- Department of Medicine, The University of Chicago, 5841 S. Maryland Avenue, MC2115, Chicago, IL, USA 60637, Tel.: +1 773 834 2451, Fax: +1 773 702 9268,
| | - Mark J Ratain
- Department of Medicine, Committee on Clinical Pharmacology & Pharmacogenomics, Cancer Research Center, The University of Chicago, 5841 S. Maryland Avenue, MC2115, Chicago, IL, USA 60637, Tel.: +1 773 702 4400, Fax: +1 773 702 3969,
| | - Federico Innocenti
- Department of Medicine, Committee on Clinical Pharmacology & Pharmacogenomics, Cancer Research Center, The University of Chicago, 5841 S. Maryland Avenue, MC2115, Chicago, IL, USA 60637, Tel.: +1 773 834 2452, Fax: +1 773 702 9268,
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Korprasertthaworn P, Udomuksorn W, Yoovathaworn K. Three novel single nucleotide polymorphisms of UGT1A9 in a Thai population. Drug Metab Pharmacokinet 2010; 24:482-5. [PMID: 19881262 DOI: 10.2133/dmpk.24.482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human UDP-glucuronosyltransferase, UGT1A9, catalyzes glucuronidation of various endobiotics and xenobiotics. In this study, we sequenced the promoter and exon 1 regions of the UGT1A9 gene in 93 Thai individuals and identified 7 genetic polymorphisms. The allele frequencies of all 3 novel single nucleotide polymorphisms (SNPs): 454A>G and 455A>C (N152A) and 760C>T (R254X) were 0.005. The other 4 known polymorphisms, -688A>C, -440T>C, -331C>T and -118A(T)(10)AT (UGT1A9(*)1b), were identified and found to have frequencies of 0.124, 0.978, 0.968 and 0.532, respectively.
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Wong YC, Zhang L, Lin G, Zuo Z. Structure–activity relationships of the glucuronidation of flavonoids by human glucuronosyltransferases. Expert Opin Drug Metab Toxicol 2009; 5:1399-419. [DOI: 10.1517/17425250903179300] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Tojcic J, Benoit-Biancamano MO, Court MH, Straka RJ, Caron P, Guillemette C. In vitro glucuronidation of fenofibric acid by human UDP-glucuronosyltransferases and liver microsomes. Drug Metab Dispos 2009; 37:2236-43. [PMID: 19661212 DOI: 10.1124/dmd.109.029058] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fenofibric acid (FA), the active moiety of fenofibrate, is an agonist of the peroxisome proliferator-activated nuclear receptor alpha that modulates triglyceride and cholesterol profiles. Lipid response to fenofibrate and FA serum concentrations is highly variable. Although FA is reported to be almost exclusively inactivated by UDP-glucuronosyltransferases (UGTs) into FA-glucuronide (FA-G), the contribution of UGT isoenzymes has never been systematically assessed. Heterologously expressed human UGT1A and UGT2B and their coding variants were tested for FA glucuronidation using liquid chromatography/mass spectrometry. Recombinant UGT2B7 presented the highest V(max)/K(m) value (2.10 microl/min/mg), 16-fold higher than the activity of other reactive UGTs, namely, UGT1A3, UGT1A6, and UGT1A9 (0.13, 0.09, and 0.02 microl/min/mg, respectively). UGT2B7.1 (His(268)) and UGT2B7.2 (Tyr(268)) enzyme activity was similar, whereas UGT1A3.2 (R(11)A(47)), UGT1A3.3 (Trp(11)), and UGT1A9.3 (Thr(33)) showed 61 to 96% reduced V(max)/K(m) values compared with the respective (1) reference proteins. FA-G formation by a human liver bank (n = 48) varied by 10-fold, but the rate of formation was not associated with common genetic variations in UGT1A3, UGT1A6, UGT1A9, and UGT2B7. Correlation with activities for the probe substrates zidovudine (UGT2B7; r(2) = 0.75), mycophenolic acid (UGT1A9; r(2) = 0.42), fulvestrant (UGT1A3; r(2) = 0.36), but not serotonin (UGT1A6; r(2) = 0.06) indicated a primary role for UGT2B7 and lesser roles of UGT1A9 and UGT1A3 in hepatic FA glucuronidation. This was confirmed by a strong correlation of FA-G formation with UGT2B7 protein content and inhibition by fluconazole, a known UGT2B7 selective inhibitor. Additional studies are required to identify genetic factors contributing to the observed FA glucuronidation variability.
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Affiliation(s)
- Jelena Tojcic
- Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de L'Université Laval Research Center and Faculty of Pharmacy, Laval University, Québec, Québec, Canada
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Olson KC, Dellinger RW, Zhong Q, Sun D, Amin S, Spratt TE, Lazarus P. Functional characterization of low-prevalence missense polymorphisms in the UDP-glucuronosyltransferase 1A9 gene. Drug Metab Dispos 2009; 37:1999-2007. [PMID: 19589876 DOI: 10.1124/dmd.108.024596] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The UDP-glucuronosyltransferase (UGT) 1A9 has been shown to play an important role in the detoxification of several carcinogens and clearance of anticancer and pain medications. The goal of the present study was to identify novel polymorphisms in UGT1A9 and characterize their effect on glucuronidation activity. The UGT1A9 gene was analyzed by direct sequencing of buccal cell genomic DNA from 90 healthy subjects. In addition to a previously identified single nucleotide polymorphism (SNP) at codon 33 resulting in an amino acid substitution (Met>Thr), two low-prevalence (<0.02) novel missense SNPs at codons 167 (Val>Ala) and 183 (Cys>Gly) were identified and are present in both white and African-American subjects. Glucuronidation activity assays using HEK293 cell lines overexpressing wild-type or variant UGT1A9 demonstrated that the UGT1A9(33Thr) and UGT1A9(183Gly) variants exhibited differential glucuronidation activities compared with wild-type UGT1A9, but this was substrate-dependent. The UGT1A9(167Ala) variant exhibited levels of activity similar to those of wild-type UGT1A9 for all substrates tested. Whereas the wild-type and UGT1A9(33Thr) and UGT1A9(167Ala) variants formed homodimers as determined by Western blot analysis of native polyacrylamide gels, the UGT1A9(183Gly) variant was incapable of homodimerization. These results suggest that several low-prevalence missense polymorphisms exist for UGT1A9 and that two of these (M33T and C183G) are functional. These results also suggest that although Cys183 is necessary for UGT1A9 homodimerization, the lack of capacity for UGT1A9 homodimerization is not sufficient to eliminate UGT1A9 activity.
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Affiliation(s)
- Kristine C Olson
- Penn State Cancer Institute, Penn State University College of Medicine, Hershey, PA 17033, USA
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Di YM, Chan E, Wei MQ, Liu JP, Zhou SF. Prediction of deleterious non-synonymous single-nucleotide polymorphisms of human uridine diphosphate glucuronosyltransferase genes. AAPS JOURNAL 2009; 11:469-80. [PMID: 19572200 DOI: 10.1208/s12248-009-9126-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Accepted: 06/15/2009] [Indexed: 01/15/2023]
Abstract
UDP glucuronosyltransferases (UGTs) are an important class of Phase II enzymes involved in the metabolism and detoxification of numerous xenobiotics including therapeutic drugs and endogenous compounds (e.g. bilirubin). To date, there are 21 human UGT genes identified, and most of them contain single-nucleotide polymorphisms (SNPs). Non-synonymous SNPs (nsSNPs) of the human UGT genes may cause absent or reduced enzyme activity and polymorphisms of UGT have been found to be closely related to altered drug clearance and/or drug response, hyperbilirubinemia, Gilbert's syndrome, and Crigler-Najjar syndrome. However, it is unlikely to study the functional impact of all identified nsSNPs in humans using laboratory approach due to its giant number. We have investigated the potential for bioinformatics approach for the prediction of phenotype based on known nsSNPs. We have identified a total of 248 nsSNPs from human UGT genes. The two algorithms tools, sorting intolerant from tolerant (SIFT) and polymorphism phenotyping (PolyPhen), were used to predict the impact of these nsSNPs on protein function. SIFT classified 35.5% of the UGT nsSNPs as "deleterious"; while PolyPhen identified 46.0% of the UGT nsSNPs as "potentially damaging" and "damaging". The results from the two algorithms were highly associated. Among 63 functionally characterized nsSNPs in the UGTs, 24 showed altered enzyme expression/activities and 45 were associated with disease susceptibility. SIFT and Polyphen had a correct prediction rate of 57.1% and 66.7%, respectively. These findings demonstrate the potential use of bioinformatics techniques to predict genotype-phenotype relationships which may constitute the basis for future functional studies.
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Affiliation(s)
- Yuan Ming Di
- Discipline of Chinese Medicine, School of Health Sciences, RMIT University, Bundoora, Melbourne, Victoria, Australia
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van Schaik RHN, van Agteren M, de Fijter JW, Hartmann A, Schmidt J, Budde K, Kuypers D, Le Meur Y, van der Werf M, Mamelok R, van Gelder T. UGT1A9 -275T>A/-2152C>T polymorphisms correlate with low MPA exposure and acute rejection in MMF/tacrolimus-treated kidney transplant patients. Clin Pharmacol Ther 2009; 86:319-27. [PMID: 19494809 DOI: 10.1038/clpt.2009.83] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Mycophenolate mofetil (MMF) is an immunosuppressive drug commonly used in the context of kidney transplantation. Exposure to the active metabolite mycophenolic acid (MPA) is associated with risk of allograft rejection. MPA pharmacokinetics varies between individuals, the potential cause being the presence of genetic polymorphisms in key enzymes. We genotyped 338 kidney transplant patients for UGT1A8, UGT1A9, UGT2B7, and MRP2 polymorphisms and recorded MPA exposure and biopsy-proven acute rejections (BPARs) during a 1-year follow-up. Tacrolimus-treated patients who were UGT1A9 -275T>A and/or -2152C>T carriers displayed a 20% lower MPA area under the concentration-time curve from 0 to 12 h (AUC(0-12)) (P = 0.012). UGT1A9*3 carriers displayed a 49% higher MPA AUC(0-12) when treated with tacrolimus and a 54% higher MPA AUC(0-12) when treated with cyclosporine (P < 0.005). Cyclosporine-treated UGT1A8*2/*2 (518GG) patients had an 18% higher MPA AUC(0-12) compared with noncarriers. Carrying the UGT1A9 -275T>A and/or -2152C>T polymorphism significantly predicted acute rejection in fixed-dose (FD) MMF-treated patients receiving tacrolimus (odds ratio 13.3, 95% confidence interval 1.1-162.3; P < 0.05). UGT1A9 -275T>A and/or -2152C>T genotyping may identify patients at risk of MPA underexposure and acute rejection when receiving treatment with MMF and tacrolimus.
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Affiliation(s)
- R H N van Schaik
- Department of Clinical Chemistry, Erasmus University Medical Centre, Rotterdam, The Netherlands.
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Bélanger AS, Caron P, Harvey M, Zimmerman PA, Mehlotra RK, Guillemette C. Glucuronidation of the antiretroviral drug efavirenz by UGT2B7 and an in vitro investigation of drug-drug interaction with zidovudine. Drug Metab Dispos 2009; 37:1793-6. [PMID: 19487252 DOI: 10.1124/dmd.109.027706] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The non-nucleoside reverse transcriptase inhibitor efavirenz (EFV) is directly conjugated by the UDP-glucuronosyltransferase (UGT) pathway to form EFV-N-glucuronide (EFV-G), but the enzyme(s) involved has not yet been identified. The glucuronidation of EFV was screened with UGT1A and UGT2B enzymes expressed in a heterologous system, and UGT2B7 was shown to be the only reactive enzyme. The apparent K(m) value of UGT2B7 (21 microM) is similar to the value observed for human liver microsomes (24 microM), whereas the variant allozyme UGT2B7*2 (Tyr(268)) displayed similar kinetic parameters. Because 3'-azido-3'-deoxythymidine (AZT), one of the most current nucleotide reverse transcriptase inhibitors prescribed in combination with EFV, is also conjugated by UGT2B7, the potential metabolic interaction between EFV and AZT has been studied using human liver microsomes. Glucuronidation of both drugs was inhibited by one another, in a concentration-dependent manner. At K(m) values (25 and 1000 microM for EFV and AZT, respectively), EFV inhibited AZT glucuronidation by 47%, whereas AZT inhibited EFV glucuronidation by 23%. With a K(i) value of 17 microM for AZT-glucuronide formation, EFV appears to be one of the most selective and potent competitive inhibitor of AZT glucuronidation in vitro. Moreover, assuming that concentrations of EFV achieved in plasma (C(max) = 12.9 microM) are in a range similar to its K(i) value, it was estimated that EFV could produce a theoretical 43% inhibition of AZT glucuronidation in vivo. We conclude that UGT2B7 has a major role in EFV glucuronidation and that EFV could potentially interfere with the hepatic glucuronidation of AZT.
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Affiliation(s)
- Anne-Sophie Bélanger
- Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy, Laval University, Québec, Canada
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Pharmacokinetic analysis of irinotecan plus bevacizumab in patients with advanced solid tumors. Cancer Chemother Pharmacol 2009; 65:97-105. [PMID: 19415281 DOI: 10.1007/s00280-009-1008-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 04/09/2009] [Indexed: 02/07/2023]
Abstract
PURPOSE The purpose of this study was to evaluate the effect of bevacizumab on the pharmacokinetics (PK) of irinotecan and its active metabolite. Exploratory analyses of the impact of variability in uridine diphosphate glucuronosyltransferase 1A (UGT1A) genes on irinotecan metabolism and toxicity were conducted. METHODS This was an open-labeled, fixed-sequence study of bevacizumab with FOLFIRI (irinotecan, leucovorin, and infusional 5-fluorouracil). Pharmacokinetic assessments were conducted in cycles 1 and 3. RESULTS Forty-five subjects were enrolled. No difference in dose-normalized AUC(0-last) for irinotecan and SN-38 between irinotecan administered alone or in combination with bevacizumab was identified. Leukopenia was associated with higher exposure to both irinotecan and SN-38. UGT1A1 polymorphisms were associated with variability in irinotecan PK. Gastrointestinal toxicity was associated with UGT1A6 genotype. No other associations between UGT1A genotypes and toxicity were detected. CONCLUSION Bevacizumab does not affect irinotecan PK when administered concurrently. A variety of pharmacogenetic relationships may influence the pharmacokinetics of irinotecan and its toxicity.
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Ménard V, Girard H, Harvey M, Pérusse L, Guillemette C. Analysis of inherited genetic variations at theUGT1locus in the French-Canadian population. Hum Mutat 2009; 30:677-87. [DOI: 10.1002/humu.20946] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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81
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Strassburg CP, Kalthoff S, Ehmer U. Variability and function of family 1 uridine-5'-diphosphate glucuronosyltransferases (UGT1A). Crit Rev Clin Lab Sci 2009; 45:485-530. [PMID: 19003600 DOI: 10.1080/10408360802374624] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The substrate spectrum of human UDP-glucuronosyltransferase 1A (UGT1A) proteins includes the glucuronidation of non-steroidal anti-inflammatory drugs, anticonvulsants, chemotherapeutics, steroid hormones, bile acids, and bilirubin. The unique genetic organization of the human UGT1A gene locus, and an increasing number of functionally relevant genetic variants define tissue specificity as well as a broad range of interindividual variabilities of glucuronidation. Genetic UGT1A variability has been conserved throughout the protein's evolution and shows ethnic diversity. It is the biochemical and genetic basis for clinical phenotypes such as Gilbert's syndrome and Crigler-Najjar's disease as well as for the potential for severe, unwanted drug side effects such as in irinotecan treatment. UGT1A variants influence the metabolic effects of xenobiotic exposure and therefore have been linked to cancer risk. Detailed knowledge of the organization, function, and pharmacogenetics of the human UGT1A gene locus is likely to significantly contribute to the improvement of drug safety and efficacy as well as to the provision of steps toward the goal of individualized drug therapy and disease risk prediction.
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Affiliation(s)
- Christian P Strassburg
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.
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83
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Kweekel D, Guchelaar HJ, Gelderblom H. Clinical and pharmacogenetic factors associated with irinotecan toxicity. Cancer Treat Rev 2008; 34:656-69. [DOI: 10.1016/j.ctrv.2008.05.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Revised: 04/29/2008] [Accepted: 05/02/2008] [Indexed: 01/26/2023]
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84
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Benoit-Biancamano MO, Connelly J, Villeneuve L, Caron P, Guillemette C. Deferiprone Glucuronidation by Human Tissues and Recombinant UDP Glucuronosyltransferase 1A6: An in Vitro Investigation of Genetic and Splice Variants. Drug Metab Dispos 2008; 37:322-9. [DOI: 10.1124/dmd.108.023101] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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85
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Takahashi H, Maruo Y, Mori A, Iwai M, Sato H, Takeuchi Y. Effect of D256N and Y483D on Propofol Glucuronidation by Human Uridine 5′-diphosphate Glucuronosyltransferase (UGT1A9). Basic Clin Pharmacol Toxicol 2008; 103:131-6. [DOI: 10.1111/j.1742-7843.2008.00247.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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86
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Argikar UA, Iwuchukwu OF, Nagar S. Update on tools for evaluation of uridine diphosphoglucuronosyltransferase polymorphisms. Expert Opin Drug Metab Toxicol 2008; 4:879-94. [DOI: 10.1517/17425255.4.7.879] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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87
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Kerdpin O, Knights KM, Elliot DJ, Miners JO. In vitro characterisation of human renal and hepatic frusemide glucuronidation and identification of the UDP-glucuronosyltransferase enzymes involved in this pathway. Biochem Pharmacol 2008; 76:249-57. [DOI: 10.1016/j.bcp.2008.04.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 04/16/2008] [Accepted: 04/24/2008] [Indexed: 10/22/2022]
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Lévesque E, Benoit-Biancamano MO, Delage R, Couture F, Guillemette C. Pharmacokinetics of mycophenolate mofetil and its glucuronide metabolites in healthy volunteers. Pharmacogenomics 2008; 9:869-79. [DOI: 10.2217/14622416.9.7.869] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We previously reported that polymorphisms in the UGT2B7 and UGT1A9 genes are associated with significant alteration in the disposition of mycophenolic acid (MPA) in healthy volunteers. Aim: This study further evaluates the impact of genetic polymorphisms at the UGT1A1, UGT1A7 and ABCC2 loci. Methods: Genetic analyses of five UGT candidate genes and ABCC2 were completed on 47 healthy subjects who received a single dose of 1.5 g mycophenolate mofetil and completed a 12-h pharmacokinetic profile. Results: Multivariate analyses indicate that the ABCC2 -24T promoter polymorphism is associated with a 25% increase in acyl mycophenolic acid phenolic glucuronide level. Subjects with combined ABCC2 -24T and UGT1A9*3 genotypes present a 169% increased exposure to AcMPAG. Homozygosity for UGT1A7 387G/391A (129Lys/131Lys) is associated with a modest but significant 7% reduction in MPA level. When these additional genetic factors are considered in the model, the effects of previously described UGT1A9 and UGT2B7 variations remain significant. No significant effect is observed for UGT1A1*28, UGT1A7 622T/C (Trp208Arg), UGT1A9 -440TC/-331CT, UGT1A9 -118 TA9/10 and seven other ABCC2 SNPs. Conclusion: We demonstrate that MPA disposition is a multigenic process, and that additional studies are required to ascertain the relationship between UGT, ABCC2 genotypes and MPA pharmacokinetics in transplant recipients.
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Affiliation(s)
- Eric Lévesque
- Laboratory of Pharmacogenomics, Oncology & Molecular Endocrinology Research Center, CHUL Research Center and Faculty of Pharmacy, Laval University, T3–48, 2705 Boul. Laurier, Québec, G1V 4G2, Canada
- Department of Hematology and Oncology, Hôtel-Dieu de Québec Hospital, Faculty of Medicine, Laval University, Québec, Canada
| | - Marie-Odile Benoit-Biancamano
- Laboratory of Pharmacogenomics, Oncology & Molecular Endocrinology Research Center, CHUL Research Center and Faculty of Pharmacy, Laval University, T3–48, 2705 Boul. Laurier, Québec, G1V 4G2, Canada
| | - Robert Delage
- Department of Hematology, Enfant-Jésus Hospital, Faculty of Medicine, Laval University, Québec, Canada
| | - Félix Couture
- Department of Hematology and Oncology, Hôtel-Dieu de Québec Hospital, Faculty of Medicine, Laval University, Québec, Canada
| | - Chantal Guillemette
- Laboratory of Pharmacogenomics, Oncology & Molecular Endocrinology Research Center, CHUL Research Center and Faculty of Pharmacy, Laval University, T3–48, 2705 Boul. Laurier, Québec, G1V 4G2, Canada
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Dai Z, Papp AC, Wang D, Hampel H, Sadee W. Genotyping panel for assessing response to cancer chemotherapy. BMC Med Genomics 2008; 1:24. [PMID: 18547414 PMCID: PMC2442111 DOI: 10.1186/1755-8794-1-24] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Accepted: 06/11/2008] [Indexed: 01/02/2023] Open
Abstract
Background Variants in numerous genes are thought to affect the success or failure of cancer chemotherapy. Interindividual variability can result from genes involved in drug metabolism and transport, drug targets (receptors, enzymes, etc), and proteins relevant to cell survival (e.g., cell cycle, DNA repair, and apoptosis). The purpose of the current study is to establish a flexible, cost-effective, high-throughput genotyping platform for candidate genes involved in chemoresistance and -sensitivity, and treatment outcomes. Methods We have adopted SNPlex for genotyping 432 single nucleotide polymorphisms (SNPs) in 160 candidate genes implicated in response to anticancer chemotherapy. Results The genotyping panels were applied to 39 patients with chronic lymphocytic leukemia undergoing flavopiridol chemotherapy, and 90 patients with colorectal cancer. 408 SNPs (94%) produced successful genotyping results. Additional genotyping methods were established for polymorphisms undetectable by SNPlex, including multiplexed SNaPshot for CYP2D6 SNPs, and PCR amplification with fluorescently labeled primers for the UGT1A1 promoter (TA)nTAA repeat polymorphism. Conclusion This genotyping panel is useful for supporting clinical anticancer drug trials to identify polymorphisms that contribute to interindividual variability in drug response. Availability of population genetic data across multiple studies has the potential to yield genetic biomarkers for optimizing anticancer therapy.
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Affiliation(s)
- Zunyan Dai
- Program in Pharmacogenomics, Department of Pharmacology, Comprehensive Cancer Center, College of Medicine and Public Health, The Ohio State University, 5072 Graves Hall, 333 West 10th Avenue, Columbus, OH 43210-1239, USA.
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90
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Joy MS, La M, Bo Xiao. Individualizing Therapy in Patients With Chronic Kidney Disease. J Pharm Pract 2008. [DOI: 10.1177/0897190008315907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Patients with chronic kidney diseases have multiple clinical abnormalities that may affect disposition of drugs, including alterations in glomerular filtration rate, excretion of plasma proteins, reductions in serum albumin, and reductions in drug metabolizing enzyme activity. Inflammation may also influence the previous factors. Concomitant drug therapies can lead to drug— drug interactions that may affect the pharmacokinetics of administered drugs. Pharmacogenomics has begun to be evaluated for effects of genotype and haplotype of drug metabolizing enzymes and transporters on drug disposition. Because of the multiple potential etiologies for alterations in drug disposition in patients with chronic kidney diseases, they require appropriate evaluation for implementation of individualized strategies in therapies to enhance efficacy and reduce toxicities. This review will highlight the disease- and patient-specific variables that are targets for patient-centered approaches to therapeutic interventions. The field of pharmacogenomics will be reviewed with reference to common therapies for transplantation and glomerular diseases.
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Affiliation(s)
- Melanie S. Joy
- School of Medicine, Division of Nephrology and Hypertension, UNC Kidney Center, University of North Carolina, School of Pharmacy, Divisions of Pharmacotherapy and Experimental Therapeutics and Molecular Pharmaceutics, University of North Carolina, Chapel Hill, North Carolina,
| | - Mary La
- School of Medicine, Division of Nephrology and Hypertension, UNC Kidney Center, University of North Carolina
| | - Bo Xiao
- School of Medicine, Division of Nephrology and Hypertension, UNC Kidney Center, University of North Carolina
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91
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Strassburg CP, Lankisch TO, Manns MP, Ehmer U. Family 1 uridine-5'-diphosphate glucuronosyltransferases (UGT1A): from Gilbert's syndrome to genetic organization and variability. Arch Toxicol 2008; 82:415-33. [PMID: 18491077 DOI: 10.1007/s00204-008-0314-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 04/30/2008] [Indexed: 12/13/2022]
Abstract
The human UDP-glucuronosyltransferase 1A gene locus is organized to generate enzymes, which share a carboxyterminal portion and are unique at their aminoterminal variable region. Expression is tissue-specific and overlapping substrate specificities include a broad spectrum of endogenous and xenobiotic compounds as well as many therapeutic drugs targeted for detoxification and elimination by glucuronidation. The absence of glucuronidation leads to fatal hyperbilirubinemia. A remarkable interindividual variability of UDP-glucuronosyltransferases is evidenced by over 100 identified genetic variants leading to alterations of catalytic activites or transcription levels. Variant alleles with lower carcinogen detoxification activity have been associated with cancer risk such as colorectal cancer and hepatocellular carcinoma. Genetic variants and haplotypes have been identified as risk factors for unwanted drug effects of the anticancer drug irinotecan and the antiviral proteinase inhibitor atazanavir. Glucuronidation and its variability are likely to represent an important factor for individualized drug therapy and risk prediction impacting the drug development and licensing processes.
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Affiliation(s)
- Christian P Strassburg
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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92
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Baldelli S, Merlini S, Perico N, Nicastri A, Cortinovis M, Gotti E, Remuzzi G, Cattaneo D. C-440T/T-331C polymorphisms in the UGT1A9 gene affect the pharmacokinetics of mycophenolic acid in kidney transplantation. Pharmacogenomics 2008; 8:1127-41. [PMID: 17924828 DOI: 10.2217/14622416.8.9.1127] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION The immunosuppressive agent mycophenolic acid (MPA) is metabolized by uridine diphosphate glucuronosyltransferase 1A9 (UGT1A9) to 7-O-glucuronide (MPAG) and excreted by multidrug resistance-associated protein 2 in the bile. By contrast, the production of the acyl MPAG, a minor MPA metabolite, was ascribed to UGT2B7 and UGT1A8. Several polymorphisms in the genes encoding for UGT1A9, UGT2B7 and MRP2 proteins have been described. However, their functional role in vivo on MPA metabolism remains poorly defined. METHODS A total of 40 Caucasian kidney transplant patients, given induction therapies (with Campath-(1)H or the combination basiliximab/rabbit antithymocyte globulin) and on maintenance immunosuppression with cyclosporine in combination with mycophenolate mofetil (MMF) in a steroid-free regimen, were enrolled in the pharmacogenetic study. Patients had clinical and hematochemical evaluations at month 6 after transplantation, as well as complete MPA pharmacokinetic assessment. They were genotyped for SNPs in UGT1A9 C-2152T, T-1887G, C-665T, C-440T, T-331C, T-275A, T98C, for the nonsynonymous C802T SNP in UGT2B7, and for ABCC2 SNPs C-24T and G1249A. The association of these polymorphisms with MPA pharmacokinetic parameters was investigated. RESULTS Differences in the MPA pharmacokinetic profiles confirmed large interpatient variability of MPA exposure, with AUC(0-12) values ranging from 7.9 to 50.1 mg*h/ml. MPA AUC(0-12) was significantly associated with the presence of UGT1A9 -440/-331 genotypes (TT/CC: 61.5 +/- 2.7 mg*h/ml/g MMF; TC/CT: 45.4 +/- 14.0 mg*h/ml/g MMF; CC/TT: 40.8 +/- 10.8 mg*h/ml/g MMF; p = 0.005), whereas MPAG exposure was mainly influenced by renal function. The positive association between MPA AUC and SNPs in position -440/-331 found in kidney transplant patients confirmed previous in vitro findings showing that the abovementioned SNPs had a significant impact on UGT1A9 protein content in the liver. The presence of ABCC2 promoter C-24T and exon 10 G1249A SNPs did not cause any significant variation in MPA and MPAG pharmacokinetic parameters. CONCLUSION The study demonstrated a significant impact of C-440T/T-331C SNPs in the promoter region of the UGT1A9 gene on MPA pharmacokinetics in renal allograft recipients.
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Affiliation(s)
- Sara Baldelli
- Mario Negri Institute for Pharmacological Research, Department of Medicine and Transplantation, Via Gavazzeni, 11-24125 Bergamo, Italy
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93
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Katz DA, Murray B, Bhathena A, Sahelijo L. Defining drug disposition determinants: a pharmacogenetic-pharmacokinetic strategy. Nat Rev Drug Discov 2008; 7:293-305. [PMID: 18382463 DOI: 10.1038/nrd2486] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In preclinical and early clinical drug development, information about the factors influencing drug disposition is used to predict drug interaction potential, estimate and understand population pharmacokinetic variability, and select doses for clinical trials. However, both in vitro drug metabolism studies and pharmacogenetic association studies on human pharmacokinetic parameters have focused on a limited subset of the proteins involved in drug disposition. Furthermore, there has been a one-way information flow, solely using results of in vitro studies to select candidate genes for pharmacogenetic studies. Here, we propose a two-way pharmacogenetic-pharmacokinetic strategy that exploits the dramatic recent expansion in knowledge of functional genetic variation in proteins that influence drug disposition, and discuss how it could improve drug development.
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Affiliation(s)
- David A Katz
- Abbott Global Pharmaceutical Research & Development, 100 Abbott Park Road, Abbott Park, Illinois 60064-3500, USA.
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94
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Ramírez J, Liu W, Mirkov S, Desai AA, Chen P, Das S, Innocenti F, Ratain MJ. Lack of association between common polymorphisms in UGT1A9 and gene expression and activity. Drug Metab Dispos 2007; 35:2149-53. [PMID: 17761781 DOI: 10.1124/dmd.107.015446] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Interindividual variability in the glucuronidation of xenobiotics metabolized by UDP-glucuronosyltransferase 1A9 (UGT1A9) suggests the presence of functional UGT1A9 variants. The aim of this study was to evaluate whether the putative functionality of the UGT1A9 variants-118T(9>10) (rs3832043), I399C>T (rs2741049), -275T>A (rs6714486), and-2152C>T (rs17868320) could be confirmed in an independent study. UGT1A9 genotypes and UGT1A9 activity (i.e., flavopiridol and mycophenolic acid glucuronidation) were determined in 46 Caucasian human livers. mRNA levels were quantitated by real-time polymerase chain reaction in 35 of these livers. In addition, samples from 60 unrelated Caucasians belonging to the HapMap Project were also genotyped to confirm the allele frequencies and linkage disequilibrium (LD) pattern observed in our Caucasian livers. The allele frequencies of the-118T(9>10), I399C>T, -275T>A, and-2152C>T variants were 0.39, 0.39, 0.02, and 0.02 in the livers, respectively. The I399C>T variant was in complete LD (r(2) = 1) with-118T(9>10) (linked alleles: C and T(9), respectively). Complete LD between these two variants was also found in the HapMap samples (frequencies of-118T(9>10) and I399C>T = 0.38). I399C>T and-118T(9>10) correlated with neither UGT1A9 activities nor mRNA levels. Because of the low frequencies of the-275T>A and-2152C>T variants, an effect on phenotype could not be evaluated. Our data demonstrate that the common I399C>T and-118T(9>10) polymorphisms do not explain interindividual variation in hepatic UGT1A9 activity and mRNA expression and are in complete LD in the donor liver samples we studied.
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95
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Kruzelock RP, Short W. Colorectal Cancer Therapeutics and the Challenges of Applied Pharmacogenomics. Curr Probl Cancer 2007; 31:315-66. [PMID: 17905192 DOI: 10.1016/j.currproblcancer.2007.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Omura K, Nakazawa T, Sato T, Iwanaga T, Nagata O. Characterization ofN-Glucuronidation of 4-(5-Pyridin-4-yl-1H-[1,2,4]triazol-3-yl) pyridine-2-carbonitrile (FYX-051): A New Xanthine Oxidoreductase Inhibitor. Drug Metab Dispos 2007; 35:2143-8. [PMID: 17761779 DOI: 10.1124/dmd.107.017251] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In humans, orally administered 4-(5-pyridin-4-yl-1H-[1,2,4]triazol-3-yl) pyridine-2-carbonitrile (FYX-051) is excreted mainly as triazole N(1)- and N(2)-glucuronides in urine. It is important to determine the enzyme(s) that catalyze the metabolism of a new drug to estimate individual differences and/or drug-drug interactions. Therefore, the characterization and mechanism of these glucuronidations were investigated using human liver microsomes (HLMs), human intestinal microsomes (HIMs), and recombinant human UDP-glucuronosyltransferase (UGT) isoforms to determine the UGT isoform(s) responsible for FYX-051 N(1)- and N(2)-glucuronidation. FYX-051 was metabolized to its N(1)- and N(2)-glucuronide forms by HLMs, and their K(m) values were 64.1 and 72.7 microM, respectively; however, FYX-051 was scarcely metabolized to its glucuronides by HIMs. Furthermore, among the recombinant human UGT isoforms, UGT1A1, UGT1A7, and UGT1A9 catalyzed the N(1)- and N(2)-glucuronidation of FYX-051. To estimate their contribution to FYX-051 glucuronidation, inhibition analysis with pooled HLMs was performed. Mefenamic acid, a UGT1A9 inhibitor, decreased FYX-051 N(1)- and N(2)-glucuronosyltransferase activities, whereas bilirubin, a UGT1A1 inhibitor, did not affect these activities. Furthermore, in the experiment using microsomes from eight human livers, the N(1)- and N(2)-glucuronidation activity of FYX-051 was found to significantly correlate with the glucuronidation activity of propofol, a specific substrate of UGT1A9 (N(1): r(2) = 0.868, p < 0.01; N(2): r(2) = 0.775, p < 0.01). These results strongly suggested that the N(1)- and N(2)-glucuronidation of FYX-051 is catalyzed mainly by UGT1A9 in human livers.
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Affiliation(s)
- Koichi Omura
- Research Laboratories 2, Fuji Yakuhin Co Ltd, Saitama, Japan.
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Sandanaraj E, Jada SR, Shu X, Lim R, Lee SC, Zhou Q, Zhou S, Goh BC, Chowbay B. Influence of UGT1A9 intronic I399C>T polymorphism on SN-38 glucuronidation in Asian cancer patients. THE PHARMACOGENOMICS JOURNAL 2007; 8:174-85. [PMID: 17700594 DOI: 10.1038/sj.tpj.6500473] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Genetic polymorphisms in hepatically expressed UGT1A1 and UGT1A9 contribute to the interindividual variability i-n irinotecan disposition and toxicity. We screened UGT1A1 (UGT1A1*60, g.-3140G>A, UGT1A1*28 and UGT1A1*6) and UGT1A9 (g.-118(T)(9>10) and I399C>T) genes for polymorphic variants in the promoter and coding regions, and the genotypic effect of UGT1A9 I399C>T polymorphism on irinotecan disposition in Asian cancer patients was investigated. Blood samples were collected from 45 patients after administration of irinotecan as a 90 min intravenous infusion of 375 mg/m(2) once in every 3 weeks. Genotypic-phenotypic correlates showed that cancer patients heterozygous or homozygous for the I399C>T allele had approximately 2-fold lower systemic exposure to SN-38 (P<0.05) and a trend towards a higher relative extent of glucuronidation (REG) of SN-38 (P>0.05). UGT1A1-1A9 diplotype analysis showed that patients harbouring the H1/H2 (TG6GT(10)T/GG6GT(9)C) diplotype had 2.4-fold lower systemic exposure to SN-38 glucuronide (SN-38G) compared with patients harbouring the H1/H5 (TG6GT(10)T/GG6GT(10)C) diplotype (P=0.025). In conclusion, this in vivo study supports the in vitro findings of Girard et al. and suggests that the UGT1A9 I399C>T variant may be an important glucuronidating allele affecting the pharmacokinetics of SN-38 and SN-38G in Asian cancer patients receiving irinotecan chemotherapy.
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Affiliation(s)
- E Sandanaraj
- Department of Pharmacy, Laboratory of Clinical Pharmacology, Division of Medical Sciences, Humphrey Oei Institute of Cancer Research, National Cancer Centre, Singapore
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van Hest RM, Hesselink DA, Vulto AG, Mathot RAA, van Gelder T. Individualization of mycophenolate mofetil dose in renal transplant recipients. Expert Opin Pharmacother 2007; 7:361-76. [PMID: 16503809 DOI: 10.1517/14656566.7.4.361] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The immunosuppressive agent mycophenolate mofetil has been successfully used over the past 10 years to prevent acute allograft rejection after renal transplantation. It has mainly been administered as a fixed dose of mycophenolate mofetil 1000 mg b.i.d. The pharmacokinetics of mycophenolic acid, the active moiety of the prodrug mycophenolate mofetil, show large between-patient variability, and exposure to mycophenolic acid correlates with the risk for acute rejection. This suggests that already excellent clinical results can be further improved by mycophenolate mofetil dose individualization. This review discusses different arguments in favour of individualization of mycophenolate mofetil dose, as well as strategies for managing mycophenolate mofetil therapy individualization, including pharmacokinetic and pharmacodynamic monitoring and dose individualization based on pharmacogenetic information. It is expected that pharmacokinetic monitoring of mycophenolic acid will offer the most effective and feasible tool for mycophenolate mofetil dose individualization.
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Affiliation(s)
- Reinier M van Hest
- Department of Hospital Pharmacy, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
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99
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Abstract
Irinotecan is widely used in the treatment of metastatic colorectal cancer and extensive small-cell lung cancer. Its use is limited by severe toxicities such as neutropenia and delayed-type diarrhea. Irinotecan is converted to its active metabolite SN-38. SN-38 is further metabolized to SN-38G by various hepatic and extrahepatic UGT1A isozymes, mainly UGT1A1. Impaired glucuronidation activity of the UGT1A1 enzyme has been linked with elevated levels of SN-38, leading to toxicities. UGT1A1*28 involves an extra TA repeat in the UGT1A1 promoter region and is the variant most frequently contributing to interpatient variability in irinotecan pharmacokinetics and toxicities. This information led to the revision of the irinotecan label by the US Food and Drug Administration. Recently, UGT1A1*6 seems to contribute to the risk of toxicity of irinotecan in Asian patients. The pharmacogenetics of irinotecan (irinogenetics) is one of few promising examples of the application of pharmacogenetics to individualized drug therapy. This review summarizes ongoing studies and unanswered questions on irinogenetics.
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Affiliation(s)
- Tae Won Kim
- Section of Oncology, Department of Medicine, Asan Medical Center, University of Ulsan, Seoul, Korea
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Iyanagi T. Molecular mechanism of phase I and phase II drug-metabolizing enzymes: implications for detoxification. ACTA ACUST UNITED AC 2007; 260:35-112. [PMID: 17482904 DOI: 10.1016/s0074-7696(06)60002-8] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Enzymes that catalyze the biotransformation of drugs and xenobiotics are generally referred to as drug-metabolizing enzymes (DMEs). DMEs can be classified into two main groups: oxidative or conjugative. The NADPH-cytochrome P450 reductase (P450R)/cytochrome P450 (P450) electron transfer systems are oxidative enzymes that mediate phase I reactions, whereas the UDP-glucuronosyltransferases (UGTs) are conjugative enzymes that mediate phase II enzymes. Both enzyme systems are localized to the endoplasmic reticulum (ER) where a number of drugs are sequentially metabolized. DMEs, including P450s and UGTs, generally have a highly plastic active site that can accommodate a wide variety of substrates. The P450 and UGT genes constitute a supergene family, in which UGT proteins are encoded by distinct genes and a complex gene. Both the P450 and UGT genes have evolved to diversify their functions. This chapter reviews advances in understanding the structure and function of the P450R/P450 and UGT enzyme systems. In particular, the coordinate biotransformation of xenobiotics by phase I and II enzymes in the ER membrane is examined.
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Affiliation(s)
- Takashi Iyanagi
- Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
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