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Burgis NE, VanWormer K, Robbins D, Smith J. An ITPA Enzyme with Improved Substrate Selectivity. Protein J 2024; 43:62-71. [PMID: 38066288 PMCID: PMC10901923 DOI: 10.1007/s10930-023-10162-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 02/29/2024]
Abstract
Recent clinical data have identified infant patients with lethal ITPA deficiencies. ITPA is known to modulate ITP concentrations in cells and has a critical function in neural development which is not understood. Polymorphism of the ITPA gene affects outcomes for both ribavirin and thiopurine based therapies and nearly one third of the human population is thought to harbor ITPA polymorphism. In a previous site-directed mutagenesis alanine screen of the ITPA substrate selectivity pocket, we identified the ITPA mutant, E22A, as a gain-of function mutant with enhanced ITP hydrolysis activity. Here we report a rational enzyme engineering experiment to investigate the biochemical properties of position 22 ITPA mutants and find that the E22D ITPA has two- and four-fold improved substrate selectivity for ITP over the canonical purine triphosphates ATP and GTP, respectively, while maintaining biological activity. The novel E22D ITPA should be considered as a platform for further development of ITPA therapies.
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Affiliation(s)
- Nicholas E Burgis
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA.
| | - Kandise VanWormer
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA
| | - Devin Robbins
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA
| | - Jonathan Smith
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA
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2
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Ali AM, Adam H, Hailu D, Engidawork E, Howe R, Abula T, Coenen MJH. Genetic variants of genes involved in thiopurine metabolism pathway are associated with 6-mercaptopurine toxicity in pediatric acute lymphoblastic leukemia patients from Ethiopia. Front Pharmacol 2023; 14:1159307. [PMID: 37251339 PMCID: PMC10214954 DOI: 10.3389/fphar.2023.1159307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 04/12/2023] [Indexed: 05/31/2023] Open
Abstract
Introduction: Genetic variation in the thiopurine S-methyltransferase (TPMT) gene by and large predicts variability in 6-mercaptopurine (6-MP) related toxicities. However, some individuals without genetic variants in TPMT still develop toxicity that necessitates 6-MP dose reduction or interruption. Genetic variants of other genes in the thiopurine pathway have been linked to 6-MP related toxicities previously. Objective: The aim of this study was to evaluate the effect of genetic variants in ITPA, TPMT, NUDT15, XDH, and ABCB1 on 6-MP related toxicities in patients with acute lymphoblastic leukemia (ALL) from Ethiopia. Methods: Genotyping of ITPA, and XDH was performed using KASP genotyping assay, while that of TPMT, NUDT15, and ABCB1 with TaqMan® SNP genotyping assays. Clinical profile of the patients was collected for the first 6 months of the maintenance phase treatment. The primary outcome was the incidence of grade 4 neutropenia. Bivariable followed by multivariable cox regression analysis was performed to identify genetic variants associated with the development of grade 4 neutropenia within the first 6 months of maintenance treatment. Results: In this study, genetic variants in XDH and ITPA were associated with 6-MP related grade 4 neutropenia and neutropenic fever, respectively. Multivariable analysis revealed that patients who are homozygous (CC) for XDH rs2281547 were 2.956 times (AHR 2.956, 95% CI = 1.494-5.849, p = 0.002) more likely to develop grade 4 neutropenia than those with the TT genotype. Conclusion: In conclusion, in this cohort, XDH rs2281547 was identified as a genetic risk factor for grade 4 hematologic toxicities in ALL patients treated with 6-MP. Genetic polymorphisms in enzymes other than TPMT involved in the 6-mercaptopurine pathway should be considered during its use to avoid hematological toxicity.
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Affiliation(s)
- Awol Mekonnen Ali
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Haileyesus Adam
- Department of Pediatrics and Child Health, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Daniel Hailu
- Department of Pediatrics and Child Health, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Ephrem Engidawork
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Rawleigh Howe
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Teferra Abula
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Marieke J. H. Coenen
- Department of Human Genetics, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, Netherlands
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Heidari M, Khalili M, Malek Hosseini SA, Geramizadeh B, Shamsaefar AR, Balouchi F, Karimi MH. Investigation of the Association Between the ITPA Gene 94C>A Gene Sequence Variant and Liver Transplant Rejection in Iranian Liver Transplant Recipients. EXP CLIN TRANSPLANT 2022; 20:1094-1098. [PMID: 36718008 DOI: 10.6002/ect.2022.0362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVES Inosine triphosphate pyrophosphatase is an enzyme encoded by the ITPA gene and functions to prevent the incorporation of thiopurine nucleotides into DNA and RNA. Thiopurine drug metabolites such as azathioprine and 6-mercaptopurine have been included in the lists of inosine triphosphate pyrophosphatase substrates. Inosine triphosphatase gene alterations are other pharmacogenetic sequence variants possibly involved in thiopurine metabolism. This study aimed to evaluate the possible association between ITPA 94C>A gene sequence variant (C-to-A substitution at nucleotide 94) in liver transplant recipients. MATERIALS AND METHODS The genotyping of ITPA 94C>A was evaluated by the polymerase chain reaction- restriction fragment length polymorphism method in 200 liver transplant recipients as well as 100 controls. Data were analyzed with SPSS statistical software. RESULTS This study showed statistically significant associations between the CA genotype of the ITPA 94C>A sequence variant and liver transplant in the rejection and nonrejection groups. Moreover, the results reported in this study showed no significant differences between sex, age, and blood group in patients with liver transplant (with or without transplant rejection). CONCLUSIONS Our results indicated that there were statistically significant associations of the CA genotype of ITPA 94C>A sequence variant with liver transplant in the rejection and nonrejection groups. Further studies are recommended.
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Affiliation(s)
- Mozhdeh Heidari
- From the Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Fan POL, Leung KT, Chan KYY, Leung AWK, Lam GKS, Chow TTW, Cheng FWT, Yuen LYP, Moriyama T, Yang JJ, Li CK. ABCC4, ITPA, NUDT15, TPMT and their interaction as genetic predictors of 6-mercaptopurine intolerance in chinese patients with acute lymphoblastic leukemia. Pediatr Hematol Oncol 2022; 39:254-266. [PMID: 34665987 DOI: 10.1080/08880018.2021.1973628] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Inter-individual variance in 6-mercaptopurine (6-MP) dose intensity is common in patients with acute lymphoblastic leukemia (ALL). We aimed to evaluate the association of common variants of ABCC4, ITPA, NUDT15, and TPMT with 6-MP dose intensity and toxicity in pediatric ALL patients. In this cohort, 13.8% of patients were intolerant to 6-MP with actual dosage less than 50% of scheduled dose. Twenty percent of patients were found to be heterozygous or homozygous mutated with NUDT15. NUDT15 c.415C > T and the genotype-predicted NUDT15 activity were significantly associated with 6-MP intolerance. TPMT*3C variants were not common in this cohort (2.8%). NUDT15 polymorphisms and genotype predicted NUDT15 activity were significantly associated with 6-MP dose intensity and leukopenia episodes. Combination of ABCC4 and ITPA variants (ABCC4 c.912G > T and ITPA c.94C > A) also showed significant positive association with 6-MP intolerance in Chinese children with ALL. Further study on pharmacogenetic screening for ALL patients to avoid 6-MP induced toxicity is recommended.Supplemental data for this article is available online at https://doi.org/10.1080/08880018.2021.1973628.
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Affiliation(s)
- Paroni O L Fan
- Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Kam-Tong Leung
- Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Kathy Y Y Chan
- Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Alex W K Leung
- Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,Department of Paediatrics & Adolescent Medicine, The Hong Kong Children's Hospital, Hong Kong SAR, China
| | - Grace K S Lam
- Department of Paediatrics & Adolescent Medicine, The Hong Kong Children's Hospital, Hong Kong SAR, China
| | - Terry T W Chow
- Department of Paediatrics & Adolescent Medicine, The Hong Kong Children's Hospital, Hong Kong SAR, China
| | - Frankie W T Cheng
- Department of Paediatrics & Adolescent Medicine, The Hong Kong Children's Hospital, Hong Kong SAR, China
| | - Liz Y P Yuen
- Department of Pathology, The Hong Kong Children's Hospital, Hong Kong SAR, China
| | - Takaya Moriyama
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jun J Yang
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Chi-Kong Li
- Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong SAR, China.,Department of Paediatrics & Adolescent Medicine, The Hong Kong Children's Hospital, Hong Kong SAR, China
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Zamzami MA. Inosine Triphosphate Pyrophosphatase (ITPase): Functions, Mutations, Polymorphisms and Its Impact on Cancer Therapies. Cells 2022; 11:384. [PMID: 35159194 PMCID: PMC8833965 DOI: 10.3390/cells11030384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/16/2022] Open
Abstract
Inosine triphosphate pyrophosphatase (ITPase) is an enzyme encoded by the ITPA gene and functions to prevent the incorporation of noncanonical purine nucleotides into DNA and RNA. Specifically, the ITPase catalyzed the hydrolysis of (deoxy) nucleoside triphosphates ((d) NTPs) into the corresponding nucleoside monophosphate with the concomitant release of pyrophosphate. Recently, thiopurine drug metabolites such as azathioprine have been included in the lists of ITPase substrates. Interestingly, inosine or xanthosine triphosphate (ITP/XTP) and their deoxy analogs, deoxy inosine or xanthosine triphosphate (dITP/dXTP), are products of important biological reactions such as deamination that take place within the cellular compartments. However, the incorporation of ITP/XTP, dITP/dXTP, or the genetic deficiency or polymorphism of the ITPA gene have been implicated in many human diseases, including infantile epileptic encephalopathy, early onset of tuberculosis, and the responsiveness of patients to cancer therapy. This review provides an up-to-date report on the ITPase enzyme, including information regarding its discovery, analysis, and cellular localization, its implication in human diseases including cancer, and its therapeutic potential, amongst others.
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Affiliation(s)
- Mazin A. Zamzami
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
- Centre of Artificial Intelligence in Precision Medicines, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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Boonyawat B, Monsereenusorn C, Photia A, Lertvivatpong N, Kaewchaivijit V, Jindatanmanusan P, Rujkijyanont P. ITPA:c.94C>A and NUDT15:c.415C>T Polymorphisms and Their Relation to Mercaptopurine-Related Myelotoxicity in Childhood Leukemia in Thailand. APPLICATION OF CLINICAL GENETICS 2021; 14:341-351. [PMID: 34349542 PMCID: PMC8326781 DOI: 10.2147/tacg.s318912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/19/2021] [Indexed: 11/30/2022]
Abstract
Background Mercaptopurine is a key agent in childhood leukemia treatment. Genetic polymorphism in the genes involving thiopurine metabolisms is related to 6-MP related toxicity. Objective This study aimed to determine the prevalence of ITPA:c.94C>A and NUDT15:c.415C>T polymorphisms among Thai children diagnosed with leukemia and their association with mercaptopurine-related myelotoxicity. Methods Patients and survivors with a diagnosis of leukemia treated with mercaptopurine-containing chemotherapy regimens were enrolled. Clinical data and laboratory parameters during treatment as well as ITPA:c.94C>A and NUDT15:c.415C>T genotypes were analyzed. Results In all, 99 patients with acute leukemia or survivors were enrolled in the study. The prevalences of ITPA:c.94C>A, NUDT15:c.415C>T, and co-occurrence of ITPA:c.94C>A and NUDT15:c.415C>T polymorphisms were 34, 17, and 4%, respectively. Numbers of absolute neutrophil count (ANC) and platelet count significantly decreased among patients carrying NUDT15:c.415C>T compared with NUDT15 wild type patients with p-values<0.001 and 0.019, respectively. The differences were not observed among patients carrying ITPA:c.94C>A compared with ITPA wild type patients. According to multivariate GEE, NUDT15:c.415C>T and co-occurrence of ITPA:c.94C>A and NUDT15:c.415C>T had a significant negative effect on ANC during treatment (coefficient: −463.81; CI: −778.53, −149.09; p-value=0.004 and coefficient: −527.56; CI: −1045.65, −9.48; p-value=0.046). No significant effect of ITPA:c.94C>A on ANC during treatment was observed. Conclusion ITPA:c.94C>A and NUDT15:c.415C>T polymorphisms are common among Thai children with leukemia. A strong association with mercaptopurine-related myelotoxicity was observed among patients carrying either NUDT15:c.415C>T alone or combined with ITPA:c.94C>A.
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Affiliation(s)
- Boonchai Boonyawat
- Division of Medical Genetics, Department of Pediatrics, Phramongkutklao College of Medicine and Phramongkutklao Hospital, Bangkok, Thailand
| | - Chalinee Monsereenusorn
- Division of Hematology-Oncology, Department of Pediatrics, Phramongkutklao College of Medicine and Phramongkutklao Hospital, Bangkok, Thailand
| | - Apichat Photia
- Division of Hematology-Oncology, Department of Pediatrics, Phramongkutklao College of Medicine and Phramongkutklao Hospital, Bangkok, Thailand
| | - Nawachai Lertvivatpong
- Division of Hematology-Oncology, Department of Pediatrics, Phramongkutklao College of Medicine and Phramongkutklao Hospital, Bangkok, Thailand
| | - Varissara Kaewchaivijit
- Department of Pediatrics, Phramongkutklao College of Medicine and Phramongkutklao Hospital, Bangkok, Thailand
| | - Punyanuch Jindatanmanusan
- Division of Hematology-Oncology, Department of Pediatrics, Phramongkutklao College of Medicine and Phramongkutklao Hospital, Bangkok, Thailand
| | - Piya Rujkijyanont
- Division of Hematology-Oncology, Department of Pediatrics, Phramongkutklao College of Medicine and Phramongkutklao Hospital, Bangkok, Thailand
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Chen ZY, Zhu YH, Zhou LY, Shi WQ, Qin Z, Wu B, Yan Y, Pei YW, Chao NN, Zhang R, Wang MY, Su ZH, Lu XJ, He ZY, Xu T. Association Between Genetic Polymorphisms of Metabolic Enzymes and Azathioprine-Induced Myelosuppression in 1,419 Chinese Patients: A Retrospective Study. Front Pharmacol 2021; 12:672769. [PMID: 34084143 PMCID: PMC8167793 DOI: 10.3389/fphar.2021.672769] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/27/2021] [Indexed: 02/05/2023] Open
Abstract
The aim of this study was to investigate the correlation between genetic polymorphisms of azathioprine-metabolizing enzymes and adverse reactions of myelosuppression. To this end, a retrospective analysis was performed on 1,419 Chinese patients involving 40 different diseases and 3 genes: ITPA (94C>A), TPMT*3 (T>C), and NUDT15 (415C>T). Strict inclusion and exclusion criteria were established to collect the relative cases, and the correlation between azathioprine and myelosuppression was evaluated by adverse drug reaction criteria. The mutation rates of the three genes were 29.32, 3.73, and 21.92% and grades I to IV myelosuppression occurred in 54 (9.28%) of the 582 patients who took azathioprine. The highest proportion of myelosuppression was observed in 5 of the 6 (83.33%) patients carrying the NUDT15 (415C>T) TT genotype and 12 of the 102 (11.76%) patients carrying the NUDT15 (415C>T) CT genotype. Only the NUDT15 (415C>T) polymorphism was found to be associated with the adverse effects of azathioprine-induced myelosuppression (odds ratio [OR], 51.818; 95% CI, 5.280–508.556; p = 0.001), which suggested that the NUDT15 (415C>T) polymorphism could be an influencing factor of azathioprine-induced myelosuppression in the Chinese population. Epistatic interactions between ITPA (94C>A) and NUDT15 (415C>T) affect the occurrence of myelosuppression. Thus, it is recommended that the genotype of NUDT15 (415C>T) and ITPA (94C>A) be checked before administration, and azathioprine should be avoided in patients carrying a homozygous NUDT15 (415C>T) mutation. This study is the first to investigate the association between genetic polymorphisms of these three azathioprine-metabolizing enzymes and myelosuppression in a large number of cases with a diverse range of diseases.
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Affiliation(s)
- Zhao-Yang Chen
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yang-Hui Zhu
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Ling-Yan Zhou
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Wei-Qiao Shi
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Zhou Qin
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Bin Wu
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yu Yan
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yu-Wen Pei
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Ning-Ning Chao
- Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Rui Zhang
- Department of Information Center, Engineering Research Center of Medical Information Technology of the Education Ministry, West China Hospital, Sichuan University, Chengdu, China
| | - Mi-Ye Wang
- Department of Information Center, Engineering Research Center of Medical Information Technology of the Education Ministry, West China Hospital, Sichuan University, Chengdu, China
| | - Ze-Hao Su
- Med-X Center for Informatics, West China Hospital, Sichuan University, Chengdu, China
| | - Xiao-Jun Lu
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Zhi-Yao He
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, China
| | - Ting Xu
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, China
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Distribution of Genetic Polymorphisms of Genes Implicated in Thiopurine Drugs Metabolism. Ther Drug Monit 2019; 40:655-659. [PMID: 30086084 DOI: 10.1097/ftd.0000000000000548] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Thiopurine-S-methyltransferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) are crucial enzymes involved in the metabolism of thiopurine drugs. Significant interethnic variation in the expression of TPMT and ITPA is caused by single nucleotide polymorphisms of genes encoding these proteins. The aim of this study was to describe the distribution of TPMT and ITPA polymorphisms in healthy Tunisian subjects and to establish the metabolizer status of thiopurine drugs in this population. A total of 309 healthy Tunisian subjects were recruited among blood donors of Fattouma Bourguiba Hospital of Monastir. A written informed consent was obtained from all subjects. Whole blood samples were collected from every subject in ethylenediaminetetraacetic acid tubes. TPMT (c.238 G > C, c.460 G > A and c.719A > G) and ITPA (c.94C > A and IVS2+21A > C) mutations were genotyped using polymerase chain reaction-restriction fragment length polymorphism. The observed frequencies of TPMT*3A and TPMT*3C alleles were both 0.8%. The phenotype distribution of TPMT was bimodal: 96.8% of subjects were extensive metabolizers and 3.2% were intermediate metabolizers. Genotyping of ITPA revealed frequencies of 9% and 3% for IVS2+21A > C and c.94C > A mutations, respectively. Accordingly, a trimodal phenotype distribution was found: 75.4% of the subjects were extensive metabolizers, 23.4% were intermediate metabolizers, and 1.2% wereslow metabolizers. Combination of TPMT and ITPA genotyping has revealed that a quarter of the Tunisian Population carries polymorphisms that reduce the metabolic activities of these enzymes.
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Nyström K, Wanrooij PH, Waldenström J, Adamek L, Brunet S, Said J, Nilsson S, Wind-Rotolo M, Hellstrand K, Norder H, Tang KW, Lagging M. Inosine Triphosphate Pyrophosphatase Dephosphorylates Ribavirin Triphosphate and Reduced Enzymatic Activity Potentiates Mutagenesis in Hepatitis C Virus. J Virol 2018; 92:e01087-18. [PMID: 30045981 PMCID: PMC6146798 DOI: 10.1128/jvi.01087-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 07/17/2018] [Indexed: 12/19/2022] Open
Abstract
A third of humans carry genetic variants of the ITP pyrophosphatase (ITPase) gene (ITPA) that lead to reduced enzyme activity. Reduced ITPase activity was earlier reported to protect against ribavirin-induced hemolytic anemia and to diminish relapse following ribavirin and interferon therapy for hepatitis C virus (HCV) genotype 2 or 3 infections. While several hypotheses have been put forward to explain the antiviral actions of ribavirin, details regarding the mechanisms of interaction between reduced ITPase activity and ribavirin remain unclear. The in vitro effect of reduced ITPase activity was assessed by means of transfection of hepatocytes (Huh7.5 cells) with a small interfering RNA (siRNA) directed against ITPA or a negative-control siRNA in the presence or absence of ribavirin in an HCV culture system. Low ribavirin concentrations strikingly depleted intracellular GTP levels in HCV-infected hepatocytes whereas higher ribavirin concentrations induced G-to-A and C-to-U single nucleotide substitutions in the HCV genome, with an ensuing reduction of HCV RNA expression and HCV core antigen production. Ribavirin triphosphate (RTP) was dephosphorylated in vitro by recombinant ITPase to a similar extent as ITP, a naturally occurring substrate of ITPase, and reducing ITPA expression in Huh 7.5 cells by siRNA increased intracellular levels of RTP in addition to increasing HCV mutagenesis and reducing progeny virus production. Our results extend the understanding of the biological impact of reduced ITPase activity, demonstrate that RTP is a substrate of ITPase, and may point to personalized ribavirin dosage according to ITPA genotype in addition to novel antiviral strategies.IMPORTANCE This study highlights the multiple modes of action of ribavirin, including depletion of intracellular GTP and increased hepatitis C virus mutagenesis. In cell culture, reduced ITP pyrophosphatase (ITPase) enzyme activity affected the intracellular concentrations of ribavirin triphosphate (RTP) and augmented the impact of ribavirin on the mutation rate and virus production. Additionally, our results imply that RTP, similar to ITP, a naturally occurring substrate of ITPase, is dephosphorylated in vitro by ITPase.
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Affiliation(s)
- Kristina Nyström
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Paulina H Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Jesper Waldenström
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ludmila Adamek
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Sofia Brunet
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Joanna Said
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Staffan Nilsson
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Department of Pathology and Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | | | - Kristoffer Hellstrand
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Helene Norder
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ka-Wei Tang
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Martin Lagging
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Vasanthakumar A, Davis JW, Abunimeh M, Söderholm J, Zha J, Dumas EO, Cohen DE, Waring JF, Lagging M. Reduced ITPase activity and favorable IL28B genetic variant protect against ribavirin-induced anemia in interferon-free regimens. PLoS One 2018; 13:e0198296. [PMID: 29851985 PMCID: PMC5979032 DOI: 10.1371/journal.pone.0198296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/16/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Genetic variants of inosine triphosphatase (ITPA) that confer reduced ITPase activity are associated with protection against ribavirin(RBV)-induced hemolytic anemia in peginterferon(IFN)/RBV-based treatment of hepatitis C virus (HCV). Patients with reduced ITPase activity showed improved treatment efficacy when treated with IFN/RBV. In addition, a genetic polymorphism near the IL28B gene is associated with an improved response to IFN/RBV treatment. RBV has been an important component of IFN-containing regimens, and is currently recommended in combination with several IFN-free regimens for treatment of harder to cure HCV infections. AIM To evaluate whether genetic variations that reduce ITPase activity impact RBV-induced anemia in IFN-free/RBV regimens. METHODS In this study, genetic analyses were conducted in the PEARL-IV trial to investigate the effect of activity-reducing ITPA variants as well as IL28B polymorphism on anemia, platelet (PLT) counts, and virologic response in HCV genotype1a-infected patients treated with the direct-acting antiviral (DAA) regimen of ombitasvir/paritaprevir/ritonavir and dasabuvir±RBV. RESULTS Reduction in ITPase activity and homozygosity for the IL28Brs12979860 CC genotype protected against RBV-induced anemia. In patients receiving RBV, reduced ITPase activity was associated with reduced plasma RBV concentration and higher PLT counts. ITPase activity had no impact on response to DAA treatment, viral kinetics, or baseline IP-10 levels. CONCLUSIONS Our study demonstrates that genetics of ITPA and IL28B may help identify patients protected from RBV-induced anemia when treated with IFN-free regimens. Our work demonstrates for the first time that IL28B genetics may also have an impact on RBV-induced anemia. This may be of particular significance in patients with difficult-to-cure HCV infections, such as patients with decompensated cirrhosis where RBV-containing regimens likely will continue to be recommended.
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Affiliation(s)
| | - Justin W. Davis
- AbbVie Inc., North Chicago, Illinois, United States of America
| | - Manal Abunimeh
- AbbVie Inc., North Chicago, Illinois, United States of America
| | - Jonas Söderholm
- AbbVie Inc., North Chicago, Illinois, United States of America
| | - Jiuhong Zha
- AbbVie Inc., North Chicago, Illinois, United States of America
| | - Emily O. Dumas
- AbbVie Inc., North Chicago, Illinois, United States of America
| | - Daniel E. Cohen
- AbbVie Inc., North Chicago, Illinois, United States of America
| | | | - Martin Lagging
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
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Peltenburg NC, Bierau J, Bakker JA, Schippers JA, Lowe SH, Paulussen ADC, van den Bosch BJC, Leers MPG, Hansen BE, Verbon A. Erythrocyte Inosine triphosphatase activity: A potential biomarker for adverse events during combination antiretroviral therapy for HIV. PLoS One 2018; 13:e0191069. [PMID: 29329318 PMCID: PMC5766130 DOI: 10.1371/journal.pone.0191069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 12/26/2017] [Indexed: 12/30/2022] Open
Abstract
The purine analogues tenofovir and abacavir are precursors of potential substrates for the enzyme Inosine 5'-triphosphate pyrophosphohydrolase (ITPase). Here, we investigated the association of ITPase activity and ITPA genotype with the occurrence of adverse events (AEs) during combination antiretroviral therapy (cART) for human immunodeficiency virus (HIV) infection. In 393 adult HIV-seropositive patients, AEs were defined as events that led to stop of cART regimen. ITPase activity ≥4 mmol IMP/mmol Hb/hour was considered as normal. ITPA genotype was determined by testing two ITPA polymorphisms: c.94C>A (p.Pro32Thr, rs1127354) and c.124+21A>C (rs7270101). Logistic regression analysis determined odds ratios for developing AEs. In tenofovir-containing regimens decreased ITPase activity was associated with less AEs (p = 0.01) and longer regimen duration (p = 0.001). In contrast, in abacavir-containing regimens decreased ITPase activity was associated with more AEs (crude p = 0.02) and increased switching of medication due to AEs (p = 0.03). ITPA genotype wt/wt was significantly associated with an increase in the occurrence of AEs in tenofovir-containing regimens. Decreased ITPase activity seems to be protective against occurrence of AEs in tenofovir-containing cART, while it is associated with an increase in AEs in abacavir-containing regimens.
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Affiliation(s)
- N. Chantal Peltenburg
- Department of Internal medicine, Division Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jörgen Bierau
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Jaap A. Bakker
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Jolanda A. Schippers
- Department of Integrated Care, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Selwyn H. Lowe
- Department of internal medicine, Division Infectious Diseases, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of Medical Microbiology, School of CAPHRI, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Aimée D. C. Paulussen
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | | | - Mathie P. G. Leers
- Department of Clinical Chemistry & Hematology, Zuyderland Medical Center, Heerlen, The Netherlands
| | - Bettina E. Hansen
- Department of Gastroenterology & Hepatology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Annelies Verbon
- Department of Internal medicine, Division Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
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13
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Liu Z, Wang S, Qi W, Wang X, Sun D, Wang H, Zhang Y, Li Z, Zhu L, Zhao P, Guo H, Zhou C, Wang J. The relationship between ITPA rs1127354 polymorphisms and efficacy of antiviral treatment in Northeast Chinese CHC patients. Medicine (Baltimore) 2017; 96:e7554. [PMID: 28723780 PMCID: PMC5521920 DOI: 10.1097/md.0000000000007554] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/22/2017] [Accepted: 06/26/2017] [Indexed: 01/04/2023] Open
Abstract
This prospective study investigated the relationship between 2 inosine triphosphatase (ITPA) polymorphisms (rs7270101 and rs1127354) and the efficacy of ribavirin-based antiviral therapy in hepatitis C virus (HCV)-infected Chinese patients.A total of 906 patients diagnosed with chronic hepatitis C receiving pegylated interferon (PEG-IFN) plus ribavirin combination therapy between January 2011 and January 2014 from 5 hepatitis centers in Northeast China were enrolled. The patients were divided into genotype 1 and non-genotype 1 groups according to the genotype of infected HCV. ITPA single nucleotide polymorphism (SNP) genotyping was performed for all patients. Ribavirin-induced hemolytic anemia and virological response (VR) were monitored during treatment and follow-up. Multivariate regression analysis was used to analyze the predictors for sustained virological response (SVR).IPTA rs7270101 variants were not detected. IPTA rs1127354 variants were detected and showed no difference between the genotype 1 and non-genotype 1 groups. IPTA rs1127354 genotype CC was related to a higher incidence of ribavirin-induced hemolytic anemia. For patients who received >80% of the planned ribavirin dose, rs1127354 variants and related ITPase were related to better SVR. Multivariate analysis showed that IPTA rs1127354 non-genotype CC, HCV genotype, a baseline HCV RNA level <4 × 10 IU/mL, IL-28B rs12979860 genotype CC, and low liver fibrosis were independent predictors for SVR during the combination therapy.IPTA rs1127354 variants and related ITPase were not only related with ribavirin-induced hemolytic anemia but also directly affected the SVR to PEG-IFN plus ribavirin combination therapy in Chinese HCV-infected patients.
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Affiliation(s)
- Zhenhua Liu
- Department of Digestive of China-Japan Union Hospital affiliated to Jilin University
| | - Song Wang
- Department of Urology of First Hospital affiliated to Jilin University, Changchun
| | - Wenqian Qi
- Department of Digestive of China-Japan Union Hospital affiliated to Jilin University
| | - Xu Wang
- Department of Digestive of China-Japan Union Hospital affiliated to Jilin University
| | - Derong Sun
- Department of Digestive of the Second Hospital of Daqing
| | - Hongguang Wang
- Department of Digestive of the People's Hospital of Jilin City
| | - Yonggui Zhang
- Department of Digestive of China-Japan Union Hospital affiliated to Jilin University
| | - Zhongxie Li
- Department of Digestive of the People's Hospital of Hunchun City, Jilin
| | - Liying Zhu
- Department of Infectious Diseases of the Fourth Hospital of Harbin Medical University, Heilongjiang, China
| | - Ping Zhao
- Department of Digestive of China-Japan Union Hospital affiliated to Jilin University
| | - Honghua Guo
- Department of Digestive of China-Japan Union Hospital affiliated to Jilin University
| | - Changyu Zhou
- Department of Digestive of China-Japan Union Hospital affiliated to Jilin University
| | - Jiangbin Wang
- Department of Digestive of China-Japan Union Hospital affiliated to Jilin University
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14
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Tanaka Y, Tamura Y, Yokomori H, Komiyama T. Rapidity and Severity of Hemoglobin Decreasing Associated with Erythrocyte Inosine Triphosphatase Activity and ATP Concentration during Chronic Hepatitis C Treatment. Biol Pharm Bull 2017; 39:615-9. [PMID: 27040635 DOI: 10.1248/bpb.b15-00617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to evaluate the association between therapy-induced hemoglobin (Hb) decreasing rapidity and severity with erythrocyte inosine triphosphatase (ITPase) activity and ATP concentration in chronic hepatitis C patients receiving chronic hepatitis C (HCV) treatment. Forty-three Japanese patients were included in the study. Erythrocyte ITPase activity before therapy was determined by HPLC-UV. Erythrocyte ATP concentrations before and during therapy were determined by luciferase assay. Genotyping for ITPA 94C>A (rs1127354) and IVS2+21 A>C (rs7270101) was conducted using TaqMan probes. The median ITPase activity (µmol/h/g hemoglobin) of ITPA 94 CC, CA, and AA genotypes was 136.8 (range, 80.4-289.6), 41.1 (24.3-93.1), and 11.8, respectively. ITPase activity and Hb decreasing showed a significantly inverse relationship at therapeutic weeks 2, 4, and 6 (p<0.01). Erythrocyte ATP concentration was decreased by therapy, and Hb decreasing was significantly and inversely correlated with erythrocyte ATP concentration at week 4 and after week 8 (p<0.001 and 0.05, respectively). ATP concentration for patients with ITPA 94CA was significantly lower than ITPA 94CC at week 4 (p=0.045). We concluded that ITPase activity plays an important function and that ATP concentration changes due to therapy are related to the Hb decreasing mechanism in the early period of therapy with HCV treatment.
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Affiliation(s)
- Yoichi Tanaka
- Department of Clinical Pharmacy, School of Pharmacy, Kitasato University
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15
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Peltenburg NC, Leers MPG, Bakker JA, Lowe SH, Vroemen WHM, Paulussen ADC, van den Bosch BJC, Bierau J, Verbon A. Inosine Triphosphate Pyrophosphohydrolase Expression: Decreased in Leukocytes of HIV-Infected Patients Using Combination Antiretroviral Therapy. J Acquir Immune Defic Syndr 2016; 73:390-395. [PMID: 27792682 DOI: 10.1097/qai.0000000000001130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE In HIV-infected patients, the enzyme Inosine triphosphate pyrophosphohydrolase (ITPase), involved in purine nucleotide homeostasis, was found to be decreased in erythrocytes. Since purine analogues are pivotal in the HIV treatment, a better understanding of ITPase expression in CD4 lymphocytes may lead to better understanding of nucleotide metabolism and (adverse) effects. DESIGN Cross-sectional, cohort, observational study. METHODS HIV-infected and control patients above 18 years were included. All DNA samples were genotyped for the 2 functional ITPA SNPs; c.94C>A (rs1127354) and g.IVS+21A>C (rs7270101). ITPase expression was determined by flow cytometry in all leukocyte subsets. RESULTS Fifty-nine HIV-infected patients and 50 controls were included. Leukocyte subtype distribution showed no difference in monocytes and granulocytes, but lymphocytes were higher in HIV-infected patients (P < 0.001). ITPase expression was highest in activated monocytes and lowest in lymphocytes. In HIV-infected patients, the percentage of ITPase positive cells was less in all leukocyte and lymphocyte subsets compared with controls (P < 0.01). In HIV-infected patients, 97.4% of CD4 lymphocytes were ITPase positive versus 99.9% in controls (P = 0.002) and 85.9% versus 99.6% of CD8 lymphocytes (P < 0.0001), respectively. Stratification according to genotype revealed no significant differences in ITPase expression in leukocytes in HIV-infected and control patients. CONCLUSIONS HIV-infection seems to be interfering with the nucleotide metabolism in leukocytes, including CD4 lymphocytes, by decreasing ITPase expression, independently of ITPA genotype. Given that active metabolites of purine-analogue reverse transcriptase inhibitors are potential substrates for ITPase, these results warrant further research towards effectiveness and adverse events of purine analogues and ITPase activity.
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Affiliation(s)
- N Chantal Peltenburg
- *Department of Internal Medicine, Division of Infectious Diseases, Erasmus MC, Rotterdam, the Netherlands;†Department of Clinical Chemistry and Hematology, Zuyderland Medical Center, Heerlen, the Netherlands;‡Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, the Netherlands;Departments of §Medical Microbiology;‖Internal Medicine, Division of Infectious Diseases, Research School CAPHRI, Maastricht University Medical Center, Maastricht, the Netherlands;¶Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, the Netherlands; and#Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, the Netherlands
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16
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Burgis NE. A disease spectrum for ITPA variation: advances in biochemical and clinical research. J Biomed Sci 2016; 23:73. [PMID: 27770805 PMCID: PMC5075207 DOI: 10.1186/s12929-016-0291-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/19/2016] [Indexed: 12/15/2022] Open
Abstract
Human ITPase (encoded by the ITPA gene) is a protective enzyme which acts to exclude noncanonical (deoxy)nucleoside triphosphates ((d)NTPs) such as (deoxy)inosine 5′-triphosphate ((d)ITP), from (d)NTP pools. Until the last few years, the importance of ITPase in human health and disease has been enigmatic. In 2009, an article was published demonstrating that ITPase deficiency in mice is lethal. All homozygous null offspring died before weaning as a result of cardiomyopathy due to a defect in the maintenance of quality ATP pools. More recently, a whole exome sequencing project revealed that very rare, severe human ITPA mutation results in early infantile encephalopathy and death. It has been estimated that nearly one third of the human population has an ITPA status which is associated with decreased ITPase activity. ITPA status has been linked to altered outcomes for patients undergoing thiopurine or ribavirin therapy. Thiopurine therapy can be toxic for patients with ITPA polymorphism, however, ITPA polymorphism is associated with improved outcomes for patients undergoing ribavirin treatment. ITPA polymorphism has also been linked to early-onset tuberculosis susceptibility. These data suggest a spectrum of ITPA-related disease exists in human populations. Potentially, ITPA status may affect a large number of patient outcomes, suggesting that modulation of ITPase activity is an important emerging avenue for reducing the number of negative outcomes for ITPA-related disease. Recent biochemical studies have aimed to provide rationale for clinical observations, better understand substrate selectivity and provide a platform for modulation of ITPase activity.
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Affiliation(s)
- Nicholas E Burgis
- Department of Chemistry and Biochemistry, Eastern Washington University, 226 Science Building, Cheney, WA, 99004, USA.
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17
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Moon W, Loftus EV. Review article: recent advances in pharmacogenetics and pharmacokinetics for safe and effective thiopurine therapy in inflammatory bowel disease. Aliment Pharmacol Ther 2016; 43:863-883. [PMID: 26876431 DOI: 10.1111/apt.13559] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 08/26/2015] [Accepted: 01/26/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Azathioprine and mercaptopurine have a pivotal role in the treatment of inflammatory bowel disease (IBD). However, because of their complex metabolism and potential toxicities, optimal use of biomarkers to predict adverse effects and therapeutic response is paramount. AIM To provide a comprehensive review focused on pharmacogenetics and pharmacokinetics for safe and effective thiopurine therapy in IBD. METHODS A literature search up to July 2015 was performed in PubMed using a combination of relevant MeSH terms. RESULTS Pre-treatment thiopurine S-methyltransferase typing plus measurement of 6-tioguanine nucleotides and 6-methylmercaptopurine ribonucleotides levels during treatment have emerged with key roles in facilitating safe and effective thiopurine therapy. Optimal use of these tools has been shown to reduce the risk of adverse effects by 3-7%, and to improve efficacy by 15-30%. For the introduction of aldehyde oxidase (AOX) into clinical practice, the association between AOX activity and AZA dose requirements should be positively confirmed. Inosine triphosphatase assessment associated with adverse effects also shows promise. Nucleoside diphosphate-linked moiety X-type motif 15 variants have been shown to predict myelotoxicity on thiopurines in East Asian patients. However, the impact of assessments of xanthine oxidase, glutathione S-transferase, hypoxanthine guanine phosphoribosyltransferase and inosine monophosphate dehydrogenase appears too low to favour incorporation into clinical practice. CONCLUSIONS Measurement of thiopurine-related enzymes and metabolites reduces the risk of adverse effects and improves efficacy, and should be considered part of standard management. However, this approach will not predict or avoid all adverse effects, and careful clinical and laboratory monitoring of patients receiving thiopurines remains essential.
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Affiliation(s)
- W Moon
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA.,Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea
| | - E V Loftus
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
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18
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Waldenström J, Färkkilä M, Rembeck K, Norkrans G, Langeland N, Mørch K, Pedersen C, Rauning Buhl M, Nieminen U, Nuutinen H, Alsiö Å, Holmström L, Jungnelius R, Lund K, Rubensson A, Torell E, Westin J, Lagging M. Short interferon and ribavirin treatment for HCV genotype 2 or 3 infection: NORDynamIC trial and real-life experience. Scand J Gastroenterol 2016; 51:337-43. [PMID: 26418670 PMCID: PMC4732462 DOI: 10.3109/00365521.2015.1087588] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 08/20/2015] [Accepted: 08/22/2015] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Interferon-free therapy for hepatitis C virus (HCV) infection is costly, and therefore patients with advanced fibrosis are prioritized. Although coupled with considerable side effects, a large proportion of genotype 2/3 infected patients achieve a sustained virological response (SVR) following interferon-based therapy. The present study evaluates experimental clinical trial and verifying real-life data with the aim of identifying patients with a high likelihood of favorable outcome following short interferon-based treatment. MATERIAL AND METHODS The impact of established response predictors, e.g. age, ITPA and IL28B genetic variants, IP-10, liver histopathology and early viral kinetics on outcome was evaluated among HCV genotype 2/3 infected patients enrolled in the NORDynamIC trial. Similarly outcome was evaluated among Finnish and Swedish real-life genotype 2/3 infected patients treated for 12-16 weeks in accordance with national guidelines. RESULTS In the NORDynamIC trial, age < 40 years or achieving HCV RNA < 1000 IU/mL day 7 were highly predictive of favorable outcome following 12 weeks therapy. Among 255 Finnish real-life patients below the age of 40 years treated for 12 weeks with interferon and ribavirin, 87% of HCV genotype 2 and 79% of genotype 3 infected patients achieved SVR, and among 117 Swedish real-life patients treated for 12-16 weeks, 97% of HCV genotype 2 and 94% of genotype 3 infected achieved SVR. CONCLUSIONS Short interferon-based therapy offers a high likelihood of achieving SVR for selected HCV genotype 2/3 infected patients, and is an acceptable option given that a thorough discussion of the side effects is provided prior to initiation.
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Affiliation(s)
- Jesper Waldenström
- Department of Infectious Medicine/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg,
Sweden
| | - Martti Färkkilä
- Clinic of Gastroenterology, Helsinki University Hospital, University of Helsinki,
Helsinki,
Finland
| | - Karolina Rembeck
- Department of Infectious Medicine/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg,
Sweden
| | - Gunnar Norkrans
- Department of Infectious Medicine/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg,
Sweden
| | - Nina Langeland
- Department of Clinical Science, University of Bergen,
Bergen,
Norway
- Department of Medicine, Haukeland University Hospital,
Bergen,
Norway
| | - Kristine Mørch
- Department of Medicine, Haukeland University Hospital,
Bergen,
Norway
| | - Court Pedersen
- Department of Infectious Diseases, University of Southern Denmark,
Odense,
Denmark
| | - Mads Rauning Buhl
- Department of Infectious Diseases, Aarhus University,
Aarhus,
Denmark
| | - Urpo Nieminen
- Clinic of Gastroenterology, Helsinki University Hospital, University of Helsinki,
Helsinki,
Finland
| | - Hannu Nuutinen
- Clinic of Gastroenterology, Helsinki University Hospital, University of Helsinki,
Helsinki,
Finland
| | - Åsa Alsiö
- Infektion, Skaraborgs Sjukhus Skövde,
Skövde,
Sweden
| | | | | | | | | | - Erik Torell
- Infektionskliniken, Gävle Sjukhus,
Gävle,
Sweden
| | - Johan Westin
- Department of Infectious Medicine/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg,
Sweden
| | - Martin Lagging
- Department of Infectious Medicine/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg,
Sweden
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19
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Awdishu L, Joy MS. Role of Pharmacogenomics in Kidney Disease and Injury. Adv Chronic Kidney Dis 2016; 23:106-19. [PMID: 26979149 DOI: 10.1053/j.ackd.2016.01.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/28/2016] [Accepted: 01/31/2016] [Indexed: 12/29/2022]
Abstract
There has been considerable excitement in the kidney community surrounding the research findings on the genetic contributions to kidney diseases. However, positive outcomes of personalized therapeutic interventions can be circumvented by unpredictable pharmacokinetics of prescribed drugs. Furthermore, unpredictable drug disposition can result in toxicities such as kidney injury. Patient covariates, disease covariates, and pharmacogenetics all contribute to variability in drug disposition. Further treatment personalization and avoidance of drug- and biologic- induced kidney injury will require extensive knowledge and expertise in renal clinical pharmacology. The current review will focus on the pharmacogenetics of drugs and biologics used in the treatment of glomerular kidney diseases and drugs implicated in inducing kidney injury phenotypes.
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20
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Frequency of ITPA gene polymorphisms in Iranian patients with acute lymphoblastic leukemia and prediction of its myelosuppressive effects. Leuk Res 2015; 39:1048-54. [DOI: 10.1016/j.leukres.2015.06.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 06/23/2015] [Accepted: 06/29/2015] [Indexed: 01/29/2023]
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21
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Odahara S, Uchiyama K, Kubota T, Ito Z, Takami S, Kobayashi H, Saito K, Koido S, Ohkusa T. A Prospective Study Evaluating Metabolic Capacity of Thiopurine and Associated Adverse Reactions in Japanese Patients with Inflammatory Bowel Disease (IBD). PLoS One 2015; 10:e0137798. [PMID: 26360046 PMCID: PMC4567281 DOI: 10.1371/journal.pone.0137798] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 08/20/2015] [Indexed: 12/26/2022] Open
Abstract
Azathioprine (AZA) is frequently used in patients with inflammatory bowel disease (IBD). However, toxic adverse reactions frequently develop and limit the clinical benefits. Currently, the precise mechanisms underlying thiopurine-related toxicity are not well understood. To investigate the relationship between the extent of thiopurine metabolism and adverse reactions in Japanese IBD patients, we prospectively observed 48 IBD patients who received AZA. We analyzed the thiopurine S-methyltransferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) gene mutations and measured the concentrations of 6-thioguanine nucleotide (6-TGN) continuously for 52 weeks. All patients possessed wild-type TPMT gene sequences. The ITPA 94C>A mutation was detected in 19 patients (39.6%). Adverse reactions developed in 14 of the 48 patients (29.2%), including leukopenia in 10 patients (20.8%). In the leukopenia group, the percentages of patients with 94C>A were higher than those in the without-leukopenia group (70.0% vs. 31.6%, P < 0.05). The average concentrations of 6-TGN in the patients with 94C>A were generally higher than those in the patients without 94C>A, however, there were no significant differences. Only 3 out of 10 patients with leukopenia exhibited high 6-TGN levels (30.0%). No negative correlations between white blood cell (WBC) counts and 6-TGN concentrations were observed. The cumulative incidence of leukopenia were higher for patients with 94C>A. Seven out of 19 patients (36.8%) with the ITPA 94C>A mutation developed leukopenia; however, this mutation may not unequivocally increase the risk of developing leukopenia. In addition, there are factors other than increased 6-TGN levels that are involved in the onset of leukopenia.
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Affiliation(s)
- Shunichi Odahara
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine (Kashiwa Hospital), Chiba, Japan
| | - Kan Uchiyama
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine (Kashiwa Hospital), Chiba, Japan
- * E-mail:
| | - Takahiro Kubota
- Department of Biopharmaceutics, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Zensho Ito
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine (Kashiwa Hospital), Chiba, Japan
| | - Shinichiro Takami
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine (Kashiwa Hospital), Chiba, Japan
| | - Hiroko Kobayashi
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine (Kashiwa Hospital), Chiba, Japan
| | - Keisuke Saito
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine (Kashiwa Hospital), Chiba, Japan
| | - Shigeo Koido
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine (Kashiwa Hospital), Chiba, Japan
| | - Toshifumi Ohkusa
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine (Kashiwa Hospital), Chiba, Japan
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Kevelam SH, Bierau J, Salvarinova R, Agrawal S, Honzik T, Visser D, Weiss MM, Salomons GS, Abbink TEM, Waisfisz Q, van der Knaap MS. Recessive ITPA mutations cause an early infantile encephalopathy. Ann Neurol 2015. [PMID: 26224535 DOI: 10.1002/ana.24496] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To identify the etiology of a novel, heritable encephalopathy in a small group of patients. METHODS Magnetic resonance imaging (MRI) pattern analysis was used to select patients with the same pattern. Homozygosity mapping and whole exome sequencing (WES) were performed to find the causal gene mutations. RESULTS Seven patients from 4 families (2 consanguineous) were identified with a similar MRI pattern characterized by T2 signal abnormalities and diffusion restriction in the posterior limb of the internal capsule, often also optic radiation, brainstem tracts, and cerebellar white matter, in combination with delayed myelination and progressive brain atrophy. Patients presented with early infantile onset encephalopathy characterized by progressive microcephaly, seizures, variable cardiac defects, and early death. Metabolic testing was unrevealing. Single nucleotide polymorphism array revealed 1 overlapping homozygous region on chromosome 20 in the consanguineous families. In all patients, WES subsequently revealed recessive predicted loss of function mutations in ITPA, encoding inosine triphosphate pyrophosphatase (ITPase). ITPase activity in patients' erythrocytes and fibroblasts was severely reduced. INTERPRETATION Until now ITPA variants have only been associated with adverse reactions to specific drugs. This is the first report associating ITPA mutations with a human disorder. ITPase is important in purine metabolism because it removes noncanonical nucleotides from the cellular nucleotide pool. Toxicity of accumulated noncanonical nucleotides, leading to neuronal apoptosis and interference with proteins normally using adenosine triphosphate/guanosine triphosphate, probably explains the disease. This study confirms that combining MRI pattern recognition to define small, homogeneous patient groups with WES is a powerful approach for providing a fast diagnosis in patients with an unclassified genetic encephalopathy.
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Affiliation(s)
- Sietske H Kevelam
- Department of Child Neurology, VU University Medical Center, Amsterdam, the Netherlands.,Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands
| | - Jörgen Bierau
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Ramona Salvarinova
- Division of Biochemical Diseases, Department of Pediatrics, University of British Columbia, British Columbia Children's Hospital, Vancouver, British Columbia, Canada
| | - Shakti Agrawal
- Department of Pediatric Neurology, Birmingham Children's Hospital, Birmingham, United Kingdom
| | - Tomas Honzik
- Department of Pediatrics, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Dennis Visser
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Marjan M Weiss
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, the Netherlands
| | - Gajja S Salomons
- Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands.,Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, the Netherlands
| | - Truus E M Abbink
- Department of Child Neurology, VU University Medical Center, Amsterdam, the Netherlands.,Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands
| | - Quinten Waisfisz
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, the Netherlands
| | - Marjo S van der Knaap
- Department of Child Neurology, VU University Medical Center, Amsterdam, the Netherlands.,Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
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23
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Rembeck K, Lagging M. Impact of IL28B, ITPA and PNPLA3 genetic variants on therapeutic outcome and progression of hepatitis C virus infection. Pharmacogenomics 2015; 16:1179-88. [PMID: 26250055 DOI: 10.2217/pgs.15.65] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chronic HCV infection comprises a broad spectrum of liver disease, ranging from no or minimal activity to active hepatitis that in time may progress to severe liver fibrosis, cirrhosis and hepatocellular carcinoma if left untreated. This review describes the impact of genetic variants of interleukin 28B (IL28B; also known as interferon-lambda 3), inosine triphosphate pyrophosphatase (ITPA) and patatin-like phospholipase domain-containing 3 (PNPLA3) on therapeutic outcome and liver disease severity in HCV-infected patients.
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Affiliation(s)
- Karolina Rembeck
- Department of Infectious Medicine, Institute of Biomedicine at Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10B, SE-413 46, Gothenburg, Sweden
| | - Martin Lagging
- Department of Infectious Medicine, Institute of Biomedicine at Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10B, SE-413 46, Gothenburg, Sweden
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24
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Sghaier I, Mouelhi L, Gazouani E, Morel V, Besma YL, Brochot E. Roles of ITPA and IL28B genotypes in chronic Hepatitis C patients treated with peginterferon plus ribavirin in Tunisian population. J Clin Virol 2015; 69:184-9. [PMID: 26209404 DOI: 10.1016/j.jcv.2015.06.102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/27/2015] [Accepted: 06/22/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND Despite considerable progress in the treatment of chronic hepatitis C, many countries do not have access to these new treatments. OBJECTIVES Predictive markers of response to treatment are therefore necessary before initiating with historical combination therapy (PEG-IFN+ribavirin) for these populations. STUDY DESIGN We therefore evaluated the influence of IL28B polymorphisms on treatment response and Inosine Triphosphate (ITPA) polymorphisms on the incidence of anaemia in a population of 120 Tunisian patients infected with HCV genotype 1b and treated. RESULTS The frequencies of favourable IL28B genotypes were 47% (CC for rs12979860) and 63% (TT for rs8099117). Patients in whom favourable IL28B alleles were identified had a higher chance of successful therapy: 82% for CC (rs12979860) and 75% for TT (rs8099117). Viral load decline during the first twelve weeks of treatment was more pronounced in patients with a favourable genotype (p<0.0001). For patients with an unfavourable genotype, the second phase of viral decline was more pronounced in patients with SVR. A viral load decline cut-off of 2.68logIU/mL at week 12 was best suited to discriminate responders from non-responders with an odds ratio of 40 (95% CI:11.53-170.3). Analysis of ITPA polymorphisms revealed that 16% of Tunisian patients presented ITPase deficiency. None of these patients experienced a decline of ribavirin doses during treatment versus 67% for patients without ITPase deficiency (p<0.001). CONCLUSION These data obtained in a Tunisian population should optimize before and during treatment the chances of success for treatments currently available in Tunisia for chronic HCV infection.
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Affiliation(s)
- Ikram Sghaier
- University of Tunis El Manar, Faculty of Sciences of Tunis, LR 206 Micro-Organisms and Bio-molecules Actives, 2092, Tunisia
| | - Leila Mouelhi
- Charles Nicolle Hospital, Hepato-Gastro-Enterology department, Tunis, Tunisia
| | - Ezzedine Gazouani
- Military Hospital of Tunis, Laboratory of Immunology, Tunis, Tunisia
| | - Virginie Morel
- Department of Virology, Amiens University Medical Centre, Amiens, France; Virology Research Unit, EA 4294, Jules Verne University of Picardie, Amiens, France
| | - Yacoubi Loueslati Besma
- University of Tunis El Manar, Faculty of Sciences of Tunis, LR 206 Micro-Organisms and Bio-molecules Actives, 2092, Tunisia
| | - Etienne Brochot
- Department of Virology, Amiens University Medical Centre, Amiens, France; Virology Research Unit, EA 4294, Jules Verne University of Picardie, Amiens, France.
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25
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Delvaux N, da Costa VD, da Costa MM, Villar LM, Coelho HSM, Esberard EBC, Flores PP, Brandão-Mello CE, Villela-Nogueira CA, de Almeida AJ, Lampe E. Inosine triphosphatase allele frequency and association with ribavirin-induced anaemia in Brazilian patients receiving antiviral therapy for chronic hepatitis C. Mem Inst Oswaldo Cruz 2015; 110:636-43. [PMID: 26154744 PMCID: PMC4569827 DOI: 10.1590/0074-02760150104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 06/08/2015] [Indexed: 12/19/2022] Open
Abstract
Inosine triphosphatase (ITPA) single nucleotide polymorphisms (SNPs) are strongly associated with protection against ribavirin (RBV)-induced anaemia in European, American and Asian patients; however, there is a paucity of data for Brazilian patients. The aim of this study was to evaluate the ITPA SNP (rs7270101/rs1127354) frequency in healthy and hepatitis C virus (HCV)-infected patients from Brazil and the association with the development of severe anaemia during antiviral therapy. ITPA SNPs were determined in 200 HCV infected patients and 100 healthy individuals by sequencing. Biochemical parameters and haemoglobin (Hb) levels were analysed in 97 patients who underwent antiviral therapy. A combination of AArs7270101+CCrs1127354 (100% ITPase activity) was observed in 236/300 individuals. Anaemia was observed in 87.5% and 86.2% of treated patients with AA (rs7270101) and CC genotypes (rs1127354), respectively. Men with AA (rs7270101) showed a considerable reduction in Hb at week 12 compared to those with AC/CC (p = 0.1475). In women, there was no influence of genotype (p = 0.5295). For rs1127354, men with the CC genotype also showed a sudden reduction in Hb compared to those with AC. Allelic distribution of rs7270101 and rs1127354 shows high rates of the genotypes AA and CC, respectively, suggesting that the study population had a great propensity for developing RBV-induced anaemia. A progressive Hb reduction during treatment was observed; however, this reduction was greater in men at week 12 than in women.
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Affiliation(s)
- Nathália Delvaux
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Hepatites
Virais, Rio de Janeiro, RJ, Brasil
| | - Vanessa Duarte da Costa
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Hepatites
Virais, Rio de Janeiro, RJ, Brasil
| | - Maristella Matos da Costa
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Hepatites
Virais, Rio de Janeiro, RJ, Brasil
| | - Livia Melo Villar
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Hepatites
Virais, Rio de Janeiro, RJ, Brasil
| | - Henrique Sérgio Moraes Coelho
- Universidade Federal do Rio de Janeiro, Hospital Universitário
Clementino Fraga Filho, Departamento de Hepatologia, Rio de Janeiro, RJ, Brasil
| | - Eliane Bordalo Cathalá Esberard
- Universidade Federal Fluminense, Hospital Universitário Antônio Pedro,
Departamento de Gastroenterologia, Rio de Janeiro, RJ, Brasil
| | - Priscila Pollo Flores
- Universidade Federal Fluminense, Hospital Universitário Antônio Pedro,
Departamento de Gastroenterologia, Rio de Janeiro, RJ, Brasil
| | - Carlos Eduardo Brandão-Mello
- Universidade Federal do Estado do Rio de Janeiro, Hospital Universitário
Gaffrée e Guinle, Departamento de Medicina Geral, Rio de Janeiro, RJ, Brasil
| | - Cristiane Alves Villela-Nogueira
- Universidade Federal do Rio de Janeiro, Hospital Universitário
Clementino Fraga Filho, Departamento de Hepatologia, Rio de Janeiro, RJ, Brasil
| | - Adilson José de Almeida
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Hepatites
Virais, Rio de Janeiro, RJ, Brasil
- Universidade Federal do Estado do Rio de Janeiro, Hospital Universitário
Gaffrée e Guinle, Departamento de Medicina Geral, Rio de Janeiro, RJ, Brasil
| | - Elisabeth Lampe
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Hepatites
Virais, Rio de Janeiro, RJ, Brasil
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26
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Matsuura K, Tanaka Y, Watanabe T, Fujiwara K, Orito E, Kurosaki M, Izumi N, Sakamoto N, Enomoto N, Yatsuhashi H, Kusakabe A, Shinkai N, Nojiri S, Joh T, Mizokami M. ITPA genetic variants influence efficacy of PEG-IFN/RBV therapy in older patients infected with HCV genotype 1 and favourable IL28B type. J Viral Hepat 2014; 21:466-74. [PMID: 24750345 DOI: 10.1111/jvh.12171] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/18/2013] [Indexed: 01/22/2023]
Abstract
Inosine triphosphatase (ITPA) genetic variants are strongly associated with ribavirin (RBV)-induced anaemia during pegylated interferon (PEG-IFN) plus RBV therapy. However, the treatment efficacy of ITPA genetic variants has not been fully explored. We enrolled 309 individuals infected with hepatitis C virus genotype 1, who were treated with PEG-IFN plus RBV for 48 weeks. The ITPA SNP: rs1127354 and IL28B SNP: rs8099917 were genotyped. We examined the risk factors for severe anaemia up to week 12 after the start of treatment and treatment efficacy. The incidence of severe anaemia, ≥ 3 g/dL reduction or <10 g/dL of haemoglobin (Hb) up to week 12, was more frequent in patients with CC at rs1127354 [65% (145/224), 33% (73/224)] than in those with CA/AA [25% (21/85), 6% (8/85)] (P < 0.0001). ITPA genotype, pretreatment Hb level and age were independent predictive factors for severe anaemia: Hb < 10 g/dL. In IL28B favourable type, the sustained virologic response rate was higher in ≥ 60-year-old patients with CA/AA than in those with CC [71% (22/31) vs 40% (26/65), P = 0.005], although there was no significant difference in treatment efficacy according to ITPA genetic variants in the <60-year-old patients. The proportion of patients administered ≥ 80% of the dosage of RBV was significantly higher in the patients with CA/AA than in those with CC (P = 0.025), resulting in a lower relapse rate. In conclusion, ITPA genetic variants were associated with severe RBV-induced anaemia and could influence the efficacy of PEG-IFN plus RBV treatment among elderly patients with IL28B favourable type.
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Affiliation(s)
- K Matsuura
- Department of Virology, Liver Unit, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan; Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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27
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Rembeck K, Waldenström J, Hellstrand K, Nilsson S, Nyström K, Martner A, Lindh M, Norkrans G, Westin J, Pedersen C, Färkkilä M, Langeland N, Buhl MR, Mørch K, Christensen PB, Lagging M. Variants of the inosine triphosphate pyrophosphatase gene are associated with reduced relapse risk following treatment for HCV genotype 2/3. Hepatology 2014; 59:2131-9. [PMID: 24519039 DOI: 10.1002/hep.27009] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/09/2014] [Indexed: 12/30/2022]
Abstract
UNLABELLED The present study evaluated the impact of variations in the inosine triphosphate pyrophosphatase (ITPase) gene (ITPA) on treatment outcome in patients with hepatitis C virus (HCV) genotype 2/3 infection receiving peginterferon-α2a and lower, conventional 800 mg daily dose of ribavirin. Previous studies using higher, weight-based ribavirin dosing report that patients carrying polymorphisms encoding reduced predicted ITPase activity show decreased risk of ribavirin-induced anemia but increased risk of thrombocytopenia, with no impact on elimination of virus. In all, 354 treatment-naïve HCV genotype 2/3-infected patients, enrolled in a phase III trial (NORDynamIC), were genotyped for ITPA (rs1127354 and rs7270101). Homo- or heterozygosity at Ars1127354 or Crs7270101 , entailing reduced ITPase activity, was observed in 37% of patients and was associated with increased likelihood of achieving sustained virological response (SVR) (P = 0.0003 in univariate and P = 0.0002 in multivariate analyses) accompanied by a reduced risk of relapse among treatment-adherent patients. The association between ITPA variants and SVR remained significant when patients were subdivided by the 12- and 24-week treatment duration arms, HCV genotype, fibrosis stage, and IL28B genotype, and was not secondary to improved adherence to therapy or less pronounced anemia. Gene variants predicting reduced predicted ITPase activity were also associated with decreased risk of anemia (P < 0.0001), increased risk of thrombocytopenia (P = 0.007), and lower ribavirin concentrations (P = 0.02). CONCLUSION These findings demonstrate a novel ribavirin-like association between polymorphisms at ITPA and treatment efficacy in chronic hepatitis C mediated by reduced relapse risk. We hypothesize that patients (63%) being homozygous for both major alleles, leading to normal ITPase activity, may benefit more from the addition of ribavirin to present and future treatment regimens for HCV in spite of concomitant increased risk of anemia.
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Affiliation(s)
- Karolina Rembeck
- Department of Infectious Diseases/Virology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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28
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Holmes JA, Roberts SK, Ali RJ, Dore GJ, Sievert W, McCaughan GW, Crawford DH, Cheng WS, Weltman MD, Bonanzinga S, Visvanathan K, Sundararajan V, Desmond PV, Bowden DS, Matthews GV, Thompson AJ. ITPA genotype protects against anemia during peginterferon and ribavirin therapy but does not influence virological response. Hepatology 2014; 59:2152-60. [PMID: 24449403 DOI: 10.1002/hep.27022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 01/15/2014] [Indexed: 12/22/2022]
Abstract
UNLABELLED On-treatment anemia is associated with higher sustained virological response (SVR) rates during peginterferon plus ribavirin (RBV) therapy. Inosine triphosphatase (ITPA) variants causing ITPase deficiency have been shown to protect against RBV-induced anemia. However, ITPase activity has not been associated with SVR. To study this discrepancy, we examined the relationships between ITPase activity, on-treatment anemia, SVR, and RBV levels in hepatitis C virus genotype 1 (HCV-1) patients from the CHARIOT study. ITPA genotype (rs7270101, rs1127354) was used to define ITPase activity in 546 patients. Plasma RBV levels were measured using high-performance liquid chromatography (HPLC). Relationships between ITPase activity, on-treatment hemoglobin (Hb) levels, RBV levels, and SVR were tested using regression modeling, survival analysis, and locally weighted scatterplot smoothing (LOWESS) plot analysis. Hb decline was independently associated with SVR (P<0.0001). ITPase deficiency was present in 35%. ITPase deficiency strongly protected against Hb decline (P<0.0001), but was not associated with SVR (P=0.28). The probability of SVR increased with lower nadir Hb for both wild-type and deficient ITPase activity, but the association curve shifted to describe a parallel relationship at higher Hb levels in patients with ITPase deficiency. In a subset (n=203), we tested the hypothesis that the association between Hb decline and SVR reflected RBV levels rather than actual Hb level. RBV levels were associated with on-treatment Hb decline and SVR, but not ITPase activity. In regression models, adjustment for RBV levels attenuated the association between Hb decline and SVR. CONCLUSION ITPase deficiency protects against RBV-induced anemia, but is not associated with SVR. Our data suggest that the relationship between Hb decline and SVR is not mechanistic, but is linked to RBV levels.
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Affiliation(s)
- Jacinta A Holmes
- St Vincent's Hospital, University of Melbourne, Melbourne, VIC, Australia; Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
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29
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Correlation of thiopurine methyltransferase and inosine triphosphate pyrophosphatase polymorphisms and adverse effects induced by azathioprine treatment in Taiwanese dermatology patients. DERMATOL SIN 2014. [DOI: 10.1016/j.dsi.2013.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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30
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Kawaguchi-Suzuki M, Frye RF. The role of pharmacogenetics in the treatment of chronic hepatitis C infection. Pharmacotherapy 2014; 34:185-201. [PMID: 24114761 DOI: 10.1002/phar.1349] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hepatitis C virus (HCV) chronically infects 170 million people worldwide. Until recently, combination therapy with peginterferon-α (pegIFN) and ribavirin (RBV) has been the standard of care. However, for many patients, especially those infected with the most common HCV genotype 1 (HCV-1), this treatment has resulted in unsatisfactory treatment response rates. Many clinical factors, including pharmacogenetics, influence the treatment response rate. Genetic variation in the interleukin 28B (IL28B) gene is the major determinant of treatment response, a finding that has been replicated in multiple independent cohorts. This review focuses on the association between pharmacogenetics and conventional pegIFN/RBV therapy in patients infected with HCV non-genotype 1; patients reinfected with HCV after liver transplantation; and patients coinfected with HCV and human immunodeficiency virus. We also review the pharmacogenetic data for boceprevir and telaprevir triple therapy in patients with HCV-1 infection, as well as viral genomic polymorphisms and genetic variants that may protect against anemia. Pharmacogenetic information offers a personalized medicine approach to help clinicians and patients make better informed decisions to maximize response and minimize toxicity for the treatment of chronic HCV infection.
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Affiliation(s)
- Marina Kawaguchi-Suzuki
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, Florida
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31
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Simone PD, Pavlov YI, Borgstahl GEO. ITPA (inosine triphosphate pyrophosphatase): from surveillance of nucleotide pools to human disease and pharmacogenetics. Mutat Res 2013; 753:131-146. [PMID: 23969025 DOI: 10.1016/j.mrrev.2013.08.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/31/2013] [Accepted: 08/02/2013] [Indexed: 01/08/2023]
Abstract
Cellular nucleotide pools are often contaminated by base analog nucleotides which interfere with a plethora of biological reactions, from DNA and RNA synthesis to cellular signaling. An evolutionarily conserved inosine triphosphate pyrophosphatase (ITPA) removes the non-canonical purine (d)NTPs inosine triphosphate and xanthosine triphosphate by hydrolyzing them into their monophosphate form and pyrophosphate. Mutations in the ITPA orthologs in model organisms lead to genetic instability and, in mice, to severe developmental anomalies. In humans there is genetic polymorphism in ITPA. One allele leads to a proline to threonine substitution at amino acid 32 and causes varying degrees of ITPA deficiency in tissues and plays a role in patients' response to drugs. Structural analysis of this mutant protein reveals that the protein is destabilized by the formation of a cavity in its hydrophobic core. The Pro32Thr allele is thought to cause the observed dominant negative effect because the resulting active enzyme monomer targets both homo- and heterodimers to degradation.
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Affiliation(s)
- Peter D Simone
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Youri I Pavlov
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, USA; Department of Pathology and Microbiology, University of Nebraska Medical Center, USA; Department of Genetics, St-Petersburg University, St-Petersburg, 199034, Russia
| | - Gloria E O Borgstahl
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, USA; Department of Pharmaceutical Sciences, University of Nebraska Medical Center, USA.
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32
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Zhao K, Lu ZX, Park JW, Zhou Q, Xing Y. GLiMMPS: robust statistical model for regulatory variation of alternative splicing using RNA-seq data. Genome Biol 2013; 14:R74. [PMID: 23876401 PMCID: PMC4054007 DOI: 10.1186/gb-2013-14-7-r74] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 06/21/2013] [Accepted: 07/22/2013] [Indexed: 11/10/2022] Open
Abstract
To characterize the genetic variation of alternative splicing, we develop GLiMMPS, a robust statistical method for detecting splicing quantitative trait loci (sQTLs) from RNA-seq data. GLiMMPS takes into account the individual variation in sequencing coverage and the noise prevalent in RNA-seq data. Analyses of simulated and real RNA-seq datasets demonstrate that GLiMMPS outperforms competing statistical models. Quantitative RT-PCR tests of 26 randomly selected GLiMMPS sQTLs yielded a validation rate of 100%. As population-scale RNA-seq studies become increasingly affordable and popular, GLiMMPS provides a useful tool for elucidating the genetic variation of alternative splicing in humans and model organisms.
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Affiliation(s)
- Keyan Zhao
- Department of Microbiology, Immunology, and Molecular Genetics, University of
California, Los Angeles, CHS 33-228, 650 Charles E. Young Drive South, Los
Angeles, CA 90095, USA
- Department of Internal Medicine, University of Iowa, 200 Hawkins Drive, Iowa City,
IA 52242, USA
| | - Zhi-xiang Lu
- Department of Microbiology, Immunology, and Molecular Genetics, University of
California, Los Angeles, CHS 33-228, 650 Charles E. Young Drive South, Los
Angeles, CA 90095, USA
- Department of Internal Medicine, University of Iowa, 200 Hawkins Drive, Iowa City,
IA 52242, USA
| | - Juw Won Park
- Department of Microbiology, Immunology, and Molecular Genetics, University of
California, Los Angeles, CHS 33-228, 650 Charles E. Young Drive South, Los
Angeles, CA 90095, USA
- Department of Internal Medicine, University of Iowa, 200 Hawkins Drive, Iowa City,
IA 52242, USA
| | - Qing Zhou
- Department of Statistics, University of California, Los Angeles, 8125 Math
Sciences Building, Los Angeles, CA 90095, USA
| | - Yi Xing
- Department of Microbiology, Immunology, and Molecular Genetics, University of
California, Los Angeles, CHS 33-228, 650 Charles E. Young Drive South, Los
Angeles, CA 90095, USA
- Department of Internal Medicine, University of Iowa, 200 Hawkins Drive, Iowa City,
IA 52242, USA
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33
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Waisertreiger ISR, Liston VG, Menezes MR, Kim HM, Lobachev KS, Stepchenkova EI, Tahirov TH, Rogozin IB, Pavlov YI. Modulation of mutagenesis in eukaryotes by DNA replication fork dynamics and quality of nucleotide pools. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:699-724. [PMID: 23055184 PMCID: PMC3893020 DOI: 10.1002/em.21735] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 08/13/2012] [Accepted: 08/15/2012] [Indexed: 06/01/2023]
Abstract
The rate of mutations in eukaryotes depends on a plethora of factors and is not immediately derived from the fidelity of DNA polymerases (Pols). Replication of chromosomes containing the anti-parallel strands of duplex DNA occurs through the copying of leading and lagging strand templates by a trio of Pols α, δ and ϵ, with the assistance of Pol ζ and Y-family Pols at difficult DNA template structures or sites of DNA damage. The parameters of the synthesis at a given location are dictated by the quality and quantity of nucleotides in the pools, replication fork architecture, transcription status, regulation of Pol switches, and structure of chromatin. The result of these transactions is a subject of survey and editing by DNA repair.
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Affiliation(s)
- Irina S.-R. Waisertreiger
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
| | - Victoria G. Liston
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
| | - Miriam R. Menezes
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
| | - Hyun-Min Kim
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, U.S.A
| | - Kirill S. Lobachev
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, U.S.A
| | - Elena I. Stepchenkova
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
- Saint Petersburg Branch of Vavilov Institute of General Genetics, Universitetskaya emb. 7/9, St Petersburg, 199034, Russia
- Department of Genetics, Saint Petersburg University, Universitetskaya emb. 7/9, St Petersburg, 199034, Russia
| | - Tahir H. Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
| | - Igor B. Rogozin
- National Center for Biotechnology Information NLM, National Institutes of Health, Bethesda, MD 20894, U.S.A
- Institute of Cytology and Genetics, 630090 Novosibirsk, Russia
| | - Youri. I. Pavlov
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
- Department of Genetics, Saint Petersburg University, Universitetskaya emb. 7/9, St Petersburg, 199034, Russia
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Brochot E, François C, Castelain S, Helle F, Van Nhien AN, Duchaussoy I, Capron D, Nguyen-Khac E, Duverlie G. A new tool to study ribavirin-induced haemolysis. Antivir Ther 2012; 17:1311-7. [PMID: 22951364 DOI: 10.3851/imp2308] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Today, treatment of chronic hepatitis C is based on a synergistic combination of pegylated interferon and ribavirin with antiprotease inhibitors. Haemolytic anaemia, which is the major side effect of ribavirin treatment, disrupts ribavirin treatment compliance and varies significantly from one patient to another. There is an individual susceptibility to ribavirin haemolysis. With a view to studying haemolysis, and thus optimizing the treatment response, we have developed a new in vitro tool for analysing the ribavirin-induced lysis of red blood cells. METHODS Resuspended red blood cells were incubated with isotonic buffer and a range of concentrations of ribavirin. Haemolysis was quantified by spectrophotometric measurement of the supernatant at 540 nm. The assay was used to test the effects of various compounds and to investigate the susceptibility of patients to haemolytic anaemia. RESULTS In our assay, the degree of haemolysis is dependent on the ribavirin concentration used and can be inhibited by the addition of dipyridamole (50% inhibitory concentration [IC(50)] 30 μM), ATP or glutathione (IC(50) 1.63 mM and 767 μM, respectively). We observed a strong decrease in red blood cell haemolysis in the presence of the ribavirin prodrug viramidine (Taribavirin(®)). When testing the performance of this assay with blood from 24 patients before treatment, we observed a strong correlation between in vitro haemolysis before treatment and the decrease in haemoglobin levels seen in vivo during subsequent treatment (P<0.001). CONCLUSIONS With this new tool it is possible to better evaluate individual susceptibility to ribavirin-induced haemolysis before the start of treatment. In addition, this model will enable the mechanism of ribavirin-induced anaemia to be further explored and allow molecules that could reduce ribavirin haemolysis to be screened and tested in vitro. This approach could help optimize current and future therapeutic strategies involving ribavirin in the treatment of chronic hepatitis C.
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Affiliation(s)
- Etienne Brochot
- Department of Virology, Amiens University Medical Center, Amiens, France.
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Gene polymorphisms involved in manifestation of leucopenia, digestive intolerance, and pancreatitis in azathioprine-treated patients. Dig Dis Sci 2012; 57:2394-401. [PMID: 22535280 DOI: 10.1007/s10620-012-2163-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 04/03/2012] [Indexed: 01/26/2023]
Abstract
BACKGROUND Approximately 10-28 % of patients experience adverse drug reactions related to treatment with thiopurines. The most serious reaction is myelosuppression, typically manifested as leucopenia, which occurs in approximately 2-5 % of patients. Other adverse drug reactions that often accompany thiopurine therapy are pancreatitis, hepatotoxicity, allergic reactions, digestive intolerance, arthralgia, febrile conditions, and rash. OBJECTIVE The objective of this study was to assess the relationship between variant alleles of thiopurine S-methyltransferase (SNPs 238G > C, 460G > A and 719A > G), inosine triphosphate diphosphatase (SNPs 94C > A and IVS2 + 21A > C), and xanthine dehydrogenase (837C > T) and the occurrence of adverse drug reactions to azathioprine therapy. METHODS Genotype was determined for 188 Caucasians diagnosed with inflammatory bowel disease treated with a standard dose of azathioprine (1.4-2.0 mg/kg/day). Allelic variants were determined by PCR-REA and real-time PCR methods. Results were statistically evaluated by use of Fisher's test and by odds ratio calculation. RESULTS Variant genotype thiopurine S-methyltransferase predisposes to development of leucopenia (P = 0.003, OR = 5, CI 95 %, 1.8058-13.8444). Although not statistically significant, we observed a trend that suggested correlation between the occurrence of digestive intolerance and the variant genotype inosine triphosphate diphosphatase (P = 0.1102; OR 15.63, CI 95 %, 1.162-210.1094), and between the occurrence of pancreatitis and the variant allele xanthine dehydrogenase 837T (P = 0.1124; OR 12,1, CI 95 %, 1.15-126.37). CONCLUSION The variant genotype thiopurine S-methyltransferase has been associated with the occurrence of leucopenia. The involvement of polymorphisms in inosine triphosphate diphosphatase and xanthine dehydrogenase genes in the development of digestive intolerance and pancreatitis will require further verification.
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Association of ITPA gene polymorphisms and the risk of ribavirin-induced anemia in HIV/hepatitis C virus (HCV)-coinfected patients receiving HCV combination therapy. Antimicrob Agents Chemother 2012; 56:2987-93. [PMID: 22430973 DOI: 10.1128/aac.06473-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Polymorphisms of the ITPA gene have been associated with anemia during combination therapy in hepatitis C virus (HCV)-monoinfected patients. Our aim was to confirm this association in HIV/HCV-coinfected patients. In this prospective, observational study, 73 HIV/HCV-coinfected patients treated with pegylated interferon plus ribavirin (RBV) were enrolled. Two single nucleotide polymorphisms within or adjacent to the ITPA gene (rs1127354 and rs7270101) were genotyped. The associations between the ITPA genotype and anemia or treatment outcome were examined. Fifty-nine patients (80.8%) had CC at rs1127354, whereas 14 (19.2%) had a CA/AA ITPA genotype. Percent decreases from baseline hemoglobin level were significantly greater in patients with the CC genotype than in those with the CA/AA genotype at week 4 (P = 0.0003), week 12 (P < 0.0001), and week 36 (P = 0.0102) but not at the end of treatment. RBV dose reduction was more often needed in patients with the CC genotype than in those with the CA/AA genotype (odds ratio [OR] = 11.81; 95% confidence interval [CI] = 1.45 to 256.17; P = 0.0039), as was erythropoietin therapy (OR = 8.28; 95% CI = 1.04 to 371.12; P = 0.0057). Risk factors independently associated with percent hemoglobin nadir decrease were RBV dose reduction (OR = 11.72; 95% CI = 6.82 to 16.63; P < 0.001), baseline hemoglobin (OR = 1.69; 95% CI = 0.23 to 3.15; P = 0.024), and body mass index (OR = -0.7; 95% CI = -1.43 to 0.03; P = 0.061). ITPA polymorphism was not an independent predictor of sustained virological response. Polymorphisms at rs1127354 in the ITPA gene influence hemoglobin levels during combination HCV therapy and the need for RBV dose reduction and erythropoietin use in HIV/HCV-coinfected patients.
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Schlecker C, Ultsch A, Geisslinger G, Lötsch J. The pharmacogenetic background of hepatitis C treatment. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2012; 751:36-48. [PMID: 22409946 DOI: 10.1016/j.mrrev.2012.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 02/20/2012] [Accepted: 02/24/2012] [Indexed: 12/16/2022]
Abstract
Insufficiently treated hepatitis C virus (HCV) infection remains a major healthcare issue. Individual therapy responses vary considerably from spontaneous clearing of the virus to lethal conditions. Host genetics currently receives a major scientific and clinical interest as an important source of interindividual variability in treatment. Mainly the associations of interleukin 28B gene (IL28B) variants with decreased HCV clearance under standard therapy are considered as "state of the art" of hepatitis C pharmacogenetics. However, a search in PubMed identified 41 genes reportedly modulating the individual therapy response, e.g., genes coding for major histocompatibility complex (HLA), the tumor necrosis factor (TNF), interleukin 10 (IL10), other interferon coding genes than IL28B (e.g., IFNAR1, IFNAR2, IFNG), several components of downstream interferon signaling as well as genes modulating side effects of current anti-HCV therapeutics (e.g., SLC28A3, ITPA involved in ribavirin associated hemolytic effects or SLC6A4 and HTR1A involved in serotonin associated psychiatric side effects). Applying knowledge discovery methods from the area of data mining and machine-learning to this comprehensive set of HCV therapy modulating genes, relating the HCV genes to the world wide knowledge on genes given in the form of the Gene Ontology (GO) knowledge base, found that the relevant genes belong to the GO subcategories of "inflammatory response" and "immune response" and "response to virus". This complex approaches to the pharmacogenomics of HCV may serve to identify future candidates for a personalization of HCV therapy and structured approach to possible new therapeutic targets for the control of hepatitis C virus.
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Affiliation(s)
- Christina Schlecker
- pharmazentrum frankfurt/ZAFES, Institute for Clinical Pharmacology, Goethe University, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
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Motomura T, Koga E, Taketomi A, Fukuhara T, Mano Y, Muto J, Konishi H, Toshima T, Uchiyama H, Yoshizumi T, Shirabe K, Maehara Y. Efficacy of splenectomy in preventing anemia in patients with recurrent hepatitis C following liver transplantation is not dependent on inosine triphosphate pyrophosphatase genotype. Hepatol Res 2012; 42:288-95. [PMID: 22181672 DOI: 10.1111/j.1872-034x.2011.00927.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
AIM A genetic polymorphism of inosine triphosphate pyrophosphatase (ITPA) has been associated with pegylated-interferon/ribavirin (PEG-IFN/RBV)-induced anemia in chronic hepatitis C patients. However, correlation of the genetic variant with anemia following liver transplantation has not been determined. METHODS Sixty-three hepatitis C virus (HCV)-positive patients who underwent liver transplantation and PEG-IFN/RBV therapy were enrolled. The rs1127354 was determined for each individual. RESULTS There was no relationship with anemia or RBV dosage in patients carrying the CC allele (CC group, n = 43) and those carrying the CA allele (CA group, n = 20). The incidence of hemoglobin (Hb) decline >3 g/dL (CC: 4.7%, CA: 0%) was relatively low, whereas the incidence of Hb levels <10 g/dL (CC: 18.6%, CA: 30.0%) was high. Univariate analysis revealed that splenectomy inversely correlated with Hb levels <10 g/dL at 4 weeks (P = 0.04). Among the 22 patients who did not undergo splenectomy, the incidence of Hb levels <10 g/dL tended to be lower in the seven patients carrying the CA allele (28.6%) than in the 15 patients with the CC allele (60.0%). CONCLUSION The ITPA genetic polymorphism does not correlate with post-transplant PEG-IFN/RBV-induced anemia. Splenectomy is useful in preventing anemia regardless of the ITPA genotype.
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Affiliation(s)
- Takashi Motomura
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Genome-wide association study of interferon-related cytopenia in chronic hepatitis C patients. J Hepatol 2012; 56:313-9. [PMID: 21703177 PMCID: PMC3634361 DOI: 10.1016/j.jhep.2011.04.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/10/2011] [Accepted: 04/08/2011] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Interferon-alfa (IFN)-related cytopenias are common and may be dose-limiting. We performed a genome wide association study on a well-characterized genotype 1 HCV cohort to identify genetic determinants of peginterferon-α (pegIFN)-related thrombocytopenia, neutropenia, and leukopenia. METHODS 1604/3070 patients in the IDEAL study consented to genetic testing. Trial inclusion criteria included a platelet (Pl) count ≥80×10(9)/L and an absolute neutrophil count (ANC) ≥1500/mm(3). Samples were genotyped using the Illumina Human610-quad BeadChip. The primary analyses focused on the genetic determinants of quantitative change in cell counts (Pl, ANC, lymphocytes, monocytes, eosinophils, and basophils) at week 4 in patients >80% adherent to therapy (n=1294). RESULTS 6 SNPs on chromosome 20 were positively associated with Pl reduction (top SNP rs965469, p=10(-10)). These tag SNPs are in high linkage disequilibrium with 2 functional variants in the ITPA gene, rs1127354 and rs7270101, that cause ITPase deficiency and protect against ribavirin (RBV)-induced hemolytic anemia (HA). rs1127354 and rs7270101 showed strong independent associations with Pl reduction (p=10(-12), p=10(-7)) and entirely explained the genome-wide significant associations. We believe this is an example of an indirect genetic association due to a reactive thrombocytosis to RBV-induced anemia: Hb decline was inversely correlated with Pl reduction (r=-0.28, p=10(-17)) and Hb change largely attenuated the association between the ITPA variants and Pl reduction in regression models. No common genetic variants were associated with pegIFN-induced neutropenia or leucopenia. CONCLUSIONS Two ITPA variants were associated with thrombocytopenia; this was largely explained by a thrombocytotic response to RBV-induced HA attenuating IFN-related thrombocytopenia. No genetic determinants of pegIFN-induced neutropenia were identified.
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Tanaka Y, Manabe A, Nakadate H, Kondoh K, Nakamura K, Koh K, Utano T, Kikuchi A, Komiyama T. The activity of the inosine triphosphate pyrophosphatase affects toxicity of 6-mercaptopurine during maintenance therapy for acute lymphoblastic leukemia in Japanese children. Leuk Res 2011; 36:560-4. [PMID: 22200619 DOI: 10.1016/j.leukres.2011.11.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 10/24/2011] [Accepted: 11/22/2011] [Indexed: 01/29/2023]
Abstract
The association between inosine triphosphate pyrophosphatase (ITPA) activity and toxicity of 6-mercaptopurine (6-MP) was retrospectively evaluated in 65 Japanese children with acute lymphoblastic leukemia (ALL). Patients with an ITPA activity of less than 126 μmol/h/gHb presented with hepatotoxicity more frequently than those with higher ITPA activity (p<0.01). The average 6-MP dose during maintenance therapy administered to two patients with the ITPA deficiency was lower than that given to the other patients. Measuring ITPA activity is important for ensuring the safety of maintenance therapy for Asians with ALL because thiopurine S-methyl transferase mutations are rare in the Asian population.
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Affiliation(s)
- Yoichi Tanaka
- Department of Clinical Pharmacy, Center for Clinical Pharmacy and Sciences, School of Pharmacy, Kitasato University, Tokyo, Japan.
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Cariani E, Villa E, Rota C, Critelli R, Trenti T. Translating pharmacogenetics into clinical practice: interleukin (IL)28B and inosine triphosphatase (ITPA) polymophisms in hepatitis C virus (HCV) infection. Clin Chem Lab Med 2011; 49:1247-1256. [PMID: 21612542 DOI: 10.1515/cclm.2011.618] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hepatitis C virus (HCV) infection is frequently characterized by evolution to chronicity and by a variable clinical course of the disease. The clinical heterogeneities of HCV infection and the imperfect predictability of the response to interferon (IFN) have suggested the need to search for a genetic basis of clinical features. This led to the discovery of genetic polymorphisms playing a major role in the evolution of infection, as well as on treatment response and adverse effects. This review will cover recent reports on the subject, focusing on the potential use of the new genetic markers in the diagnostic algorithm for the stratification of patients for personalized antiviral regimens.
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Affiliation(s)
- Elisabetta Cariani
- Clinical Pathology-Toxicology, Ospedale Civile S. Agostino-Estense, Modena, Italy
| | - Erica Villa
- Department of Gastroenterology, Azienda Ospedaliera-Universitaria, University of Modena and Reggio Emilia, Modena, Italy
| | - Cristina Rota
- Clinical Pathology-Toxicology, Ospedale Civile S. Agostino-Estense, Modena, Italy
| | - Rosina Critelli
- Department of Gastroenterology, Azienda Ospedaliera-Universitaria, University of Modena and Reggio Emilia, Modena, Italy
| | - Tommaso Trenti
- Clinical Pathology-Toxicology, Ospedale Civile S. Agostino-Estense, Modena, Italy
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Association Between Adverse Effects Under Azathioprine Therapy and Inosine Triphosphate Pyrophosphatase Activity in Patients With Chronic Inflammatory Bowel Disease. Ther Drug Monit 2011; 33:321-8. [DOI: 10.1097/ftd.0b013e31821a7c34] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Hitomi Y, Cirulli ET, Fellay J, McHutchison JG, Thompson AJ, Gumbs CE, Shianna KV, Urban TJ, Goldstein DB. Inosine triphosphate protects against ribavirin-induced adenosine triphosphate loss by adenylosuccinate synthase function. Gastroenterology 2011; 140:1314-21. [PMID: 21199653 DOI: 10.1053/j.gastro.2010.12.038] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 11/09/2010] [Accepted: 12/14/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Genetic variation of inosine triphosphatase (ITPA) causing an accumulation of inosine triphosphate (ITP) has been shown to protect patients against ribavirin (RBV)-induced anemia during treatment for chronic hepatitis C infection by genome-wide association study (GWAS). However, the biologic mechanism by which this occurs is unknown. METHODS We examined whether ITP can be used by adenosine triphosphatase (ATPase) in human erythrocytes or recombinant human adenylosuccinate synthase (ADSS). RBV-induced adenosine triphosphate (ATP) reduction in erythrocytes was compared with the genetically determined low or normal activity of ITPA, leading respectively to high or normal ITP levels. RESULTS Although ITP is not used directly by human erythrocyte ATPase, it can be used for ATP biosynthesis via ADSS in place of guanosine triphosphate (GTP). With RBV challenge, erythrocyte ATP reduction was more severe in the wild-type ITPA genotype than in the hemolysis protective ITPA genotype. This difference also remains after inhibiting adenosine uptake using nitrobenzylmercaptopurine riboside (NBMPR). Interestingly, the alleviation of ATP reduction by the hemolysis protective ITPA genotype was canceled by the ADSS inhibitor 6-mercaptoethanol (6-MP). CONCLUSIONS ITP confers protection against RBV-induced ATP reduction by substituting for erythrocyte GTP, which is depleted by RBV, in the biosynthesis of ATP. Because patients with excess ITP appear largely protected against anemia, these results confirm that RBV-induced anemia is due primarily to the effect of the drug on GTP and consequently ATP levels in erythrocytes.
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Affiliation(s)
- Yuki Hitomi
- Center for Human Genome Variation, School of Medicine, Duke University, Durham, North Carolina, USA
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Suzuki F, Suzuki Y, Akuta N, Sezaki H, Hirakawa M, Kawamura Y, Hosaka T, Kobayashi M, Saito S, Arase Y, Ikeda K, Kobayashi M, Chayama K, Kamatani N, Nakamura Y, Miyakawa Y, Kumada H. Influence of ITPA polymorphisms on decreases of hemoglobin during treatment with pegylated interferon, ribavirin, and telaprevir. Hepatology 2011; 53:415-21. [PMID: 21246582 DOI: 10.1002/hep.24058] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 10/01/2010] [Indexed: 12/11/2022]
Abstract
UNLABELLED Polymorphisms of the inosine triphosphatase (ITPA) gene influence anemia during pegylated interferon (PEG-IFN) and ribavirin (RBV) therapy, but their effects during triple therapy with PEG-IFN, RBV, and telaprevir are not known. Triple therapy for 12 weeks, followed by PEG-IFN and RBV for 12 weeks, was given to 49 patients with RBV-sensitive (CC at rs1127354) and 12 with RBV-resistant (CA/AA) ITPA genotypes who had been infected with hepatitis C virus (HCV) of genotype 1. Decreases in hemoglobin levels were greater in patients with CC than CA/AA genotypes at week 2 (-1.63 ± 0.92 vs. -0.48 ± 0.75 g/dL, P = 0.001) and week 4 (-3.5 ± 1.1 vs. -2.2 ± 0.96, P = 0.001), as well as at the end of treatment (-2.9 ± 1.1 vs. -2.0 ± 0.86, P = 0.013). Risk factors for hemoglobin <11.0 g/dL at week 4 were female gender, age >50 years, body mass index (BMI) <23, and CC at rs1127354 by multivariate analysis. RBV dose during the first 12 weeks was smaller in patients with CC than CA/AA genotypes (52 ± 14% vs. 65 ± 21% of the target dose, P = 0.039), but the total RBV dose was no different between them (49 ± 17% and 54 ± 18% of the target, P = 0.531). Sustained virological response (SVR) was achieved in 70% and 64% of them, respectively (P = 0.724). CONCLUSION ITPA polymorphism influences hemoglobin levels during triple therapy, particularly during the first 12 weeks while telaprevir is given. With careful monitoring of anemia and prompt adjustment of RBV dose, SVR can be achieved comparably frequently between patients with CC and CA/AA genotypes.
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Thompson AJ, Santoro R, Piazzolla V, Clark PJ, Naggie S, Tillmann HL, Patel K, Muir AJ, Shianna KV, Mottola L, Petruzzellis D, Romano M, Sogari F, Facciorusso D, Goldstein DB, McHutchison JG, Mangia A. Inosine triphosphatase genetic variants are protective against anemia during antiviral therapy for HCV2/3 but do not decrease dose reductions of RBV or increase SVR. Hepatology 2011; 53:389-95. [PMID: 21274861 PMCID: PMC4892367 DOI: 10.1002/hep.24068] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 10/28/2010] [Indexed: 12/12/2022]
Abstract
UNLABELLED Two functional variants in the inosine triphosphatase (ITPA) gene causing inosine triphosphatase (ITPase) deficiency protect against ribavirin (RBV)-induced hemolytic anemia and the need for RBV dose reduction in patients with genotype 1 hepatitis C virus (HCV). No data are available for genotype 2/3 HCV. We evaluated the association between the casual ITPA variants and on-treatment anemia in a well-characterized cohort of genotype 2/3 patients treated with variable-duration pegylated interferon alfa-2b (PEG-IFN-α2b) and RBV. Two hundred thirty-eight Caucasian patients were included in this retrospective study [185 (78%) with genotype 2 and 53 (22%) with genotype 3]. Patients were treated with PEG-IFN-α2b plus weight-based RBV (1000/1200 mg) for 12 (n = 109) or 24 weeks (n = 129). The ITPA polymorphisms rs1127354 and rs7270101 were genotyped, and an ITPase deficiency variable was defined that combined both ITPA variants according to their effect on ITPase activity. The primary endpoint was hemoglobin (Hb) reduction in week 4. We also considered Hb reduction over the course of therapy, the need for RBV dose modification, and the rate of sustained virological response (SVR). The ITPA variants were strongly and independently associated with protection from week 4 anemia (P = 10(-6) for rs1127354 and P = 10(-7) for rs7270101). Combining the variants into the ITPase deficiency variable increased the strength of association (P = 10(-11) ). ITPase deficiency protected against anemia throughout treatment. ITPase deficiency was associated with a delayed time to an Hb level < 10 g/dL (hazard ratio = 0.25, 95% confidence interval = 0.08-0.84, P = 0.025) but not with the rate of RBV dose modification (required per protocol at Hb < 9.5 g/dL). There was no association between the ITPA variants and SVR. CONCLUSION Two ITPA variants were strongly associated with protection against treatment-related anemia in patients with genotype 2/3 HCV, but they did not decrease the need for RBV dose reduction or increase the rate of SVR.
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Affiliation(s)
- Alexander J. Thompson
- Duke Clinical Research Institute, Durham, NC,Duke University Medical Center, Durham, NC
| | - Rosanna Santoro
- Gastroenterology Unit, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo, Italy
| | - Valeria Piazzolla
- Gastroenterology Unit, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo, Italy
| | - Paul J. Clark
- Duke Clinical Research Institute, Durham, NC,Duke University Medical Center, Durham, NC
| | - Susanna Naggie
- Duke Clinical Research Institute, Durham, NC,Duke University Medical Center, Durham, NC
| | - Hans L. Tillmann
- Duke Clinical Research Institute, Durham, NC,Duke University Medical Center, Durham, NC
| | - Keyur Patel
- Duke Clinical Research Institute, Durham, NC,Duke University Medical Center, Durham, NC
| | - Andrew J. Muir
- Duke Clinical Research Institute, Durham, NC,Duke University Medical Center, Durham, NC
| | - Kevin V. Shianna
- Center for Human Genome Variation, Institute for Genome Sciences & Policy, Duke University, Durham, NC
| | - Leonardo Mottola
- Gastroenterology Unit, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo, Italy
| | - Daniela Petruzzellis
- Gastroenterology Unit, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo, Italy
| | - Mario Romano
- Department of Internal Medicine, Sandro Pertini Hospital, Rome, Italy
| | - Fernando Sogari
- Department of Internal Medicine, Santissima Annunziata Hospital, Taranto, Italy
| | - Domenico Facciorusso
- Gastroenterology Unit, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo, Italy
| | - David B. Goldstein
- Center for Human Genome Variation, Institute for Genome Sciences & Policy, Duke University, Durham, NC
| | - John G. McHutchison
- Duke Clinical Research Institute, Durham, NC,Duke University Medical Center, Durham, NC
| | - Alessandra Mangia
- Gastroenterology Unit, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo, Italy
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Kurosaki M, Tanaka Y, Tanaka K, Suzuki Y, Hoshioka Y, Tamaki N, Kato T, Yasui Y, Hosokawa T, Ueda K, Tsuchiya K, Kuzuya T, Nakanishi H, Itakura J, Takahashi Y, Asahina Y, Matsuura K, Sugauchi F, Enomoto N, Nishida N, Tokunaga K, Mizokami M, Izumi N. Relationship between polymorphisms of the inosine triphosphatase gene and anaemia or outcome after treatment with pegylated interferon and ribavirin. Antivir Ther 2011; 16:685-94. [PMID: 21817190 DOI: 10.3851/imp1796] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND A genome-wide association study revealed an association between variants of the inosine triphosphatase (ITPA) gene and ribavirin (RBV)-induced anaemia. The aim of this study was to replicate this finding in an independent Japanese cohort and to define a method to allow pretreatment prediction of anaemia in combination with other factors. METHODS Genotype 1b chronic hepatitis C patients (n=132) treated with pegylated interferon (PEG-IFN)-α and RBV for 48 weeks were genotyped for ITPA rs1127354 and examined for anaemia and treatment outcome. RESULTS Variants of the ITPA gene protected against severe anaemia throughout the 48-week treatment period and were associated with lower incidence of anaemia-related RBV dose reduction. A combination of the ITPA genotype with baseline haemoglobin (Hb) and creatinine clearance (CLcr) levels predicted severe anaemia with high accuracy (90% sensitivity and 62% specificity). Among a subset of patients with the IL28B genotype of TT at rs8099917, patients with variants of the ITPA gene were associated with a higher rate of receiving >80% of the expected RBV dose, a higher rate of sustained virological response (SVR), and a lower rate of relapse. CONCLUSIONS The variants of the ITPA gene, which could protect against haemolytic anaemia and RBV dose reduction, were associated with a high rate of SVR by standard PEG-IFN and RBV therapy in a subset of Japanese patients with the favourable TT genotype at rs8099917 of IL28B. A combination of ITPA genetic polymorphisms with baseline Hb and CLcr levels further improves the predictive accuracy of severe anaemia.
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Affiliation(s)
- Masayuki Kurosaki
- Division of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan
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Thompson AJ, Fellay J, Patel K, Tillmann HL, Naggie S, Ge D, Urban TJ, Shianna KV, Muir AJ, Fried MW, Afdhal NH, Goldstein DB, Mchutchison JG. Variants in the ITPA gene protect against ribavirin-induced hemolytic anemia and decrease the need for ribavirin dose reduction. Gastroenterology 2010; 139:1181-9. [PMID: 20547162 PMCID: PMC3086671 DOI: 10.1053/j.gastro.2010.06.016] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 05/28/2010] [Accepted: 06/07/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS In a genome-wide association study of patients being treated for chronic hepatitis C, 2 functional variants in ITPA that cause inosine triphosphatase (ITPase) deficiency were shown to protect against ribavirin (RBV)-induced hemolytic anemia during early stages of treatment. We aimed to replicate this finding in an independent cohort from the Study of Viral Resistance to Antiviral Therapy of Chronic Hepatitis C and to investigate the effects of these variants beyond week 4. METHODS Genetic material was available from 318 patients. The ITPA variants, rs1127354 (exon 2, P32T) and rs7270101 (intron 2, splice altering), were genotyped and tested for association with hemoglobin (Hb) reduction at week 4. An ITPase deficiency variable was defined that combined both ITPA variants according to documented effect on ITPase activity. We investigated the impact of ITPA variants on Hb levels over the course of therapy and on the need for RBV dose reduction. RESULTS The final analysis included 304 patients with genotype 1 hepatitis C virus (167 white patients and 137 black patients). The polymorphisms rs1127354 and rs7270101 were associated with Hb reduction at week 4 (P = 3.1 × 10(-13) and 1.3 × 10(-3), respectively). The minor alleles of each variant protected against Hb reduction. Combining the variants into the ITPase deficiency variable strengthened the association (P = 2.4 × 10(-18)). The ITPase deficiency variable was associated with lower rates of anemia over the entire treatment period (48 weeks), as well as a lower rate of anemia-related RBV dose reduction (hazard ratio, 0.52; P = .0037). No association with sustained virological response was observed. CONCLUSIONS Two polymorphisms that cause ITPase deficiency are strongly associated with protection from RBV-induced hemolytic anemia and decrease the need for RBV dose reduction.
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Affiliation(s)
| | - Jacques Fellay
- Center for Human Genome Variation, Duke University, Durham, North Carolina
| | - Keyur Patel
- Duke Clinical Research Institute, Durham, North Carolina,Duke University Medical Center, Durham, North Carolina
| | - Hans L. Tillmann
- Duke Clinical Research Institute, Durham, North Carolina,Duke University Medical Center, Durham, North Carolina
| | - Susanna Naggie
- Duke Clinical Research Institute, Durham, North Carolina,Duke University Medical Center, Durham, North Carolina
| | - Dongliang Ge
- Center for Human Genome Variation, Duke University, Durham, North Carolina
| | - Thomas J. Urban
- Center for Human Genome Variation, Duke University, Durham, North Carolina
| | - Kevin V. Shianna
- Center for Human Genome Variation, Duke University, Durham, North Carolina
| | - Andrew J. Muir
- Duke Clinical Research Institute, Durham, North Carolina,Duke University Medical Center, Durham, North Carolina
| | - Michael W. Fried
- Department of Hepatology and Gastroenterology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | | | - David B. Goldstein
- Center for Human Genome Variation, Duke University, Durham, North Carolina
| | - John G. Mchutchison
- Duke Clinical Research Institute, Durham, North Carolina,Duke University Medical Center, Durham, North Carolina
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48
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Waisertreiger ISR, Menezes MR, Randazzo J, Pavlov YI. Elevated Levels of DNA Strand Breaks Induced by a Base Analog in the Human Cell Line with the P32T ITPA Variant. J Nucleic Acids 2010; 2010. [PMID: 20936128 PMCID: PMC2948936 DOI: 10.4061/2010/872180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 07/11/2010] [Indexed: 12/29/2022] Open
Abstract
Base analogs are powerful antimetabolites and dangerous mutagens generated endogenously by oxidative stress, inflammation, and aberrant nucleotide biosynthesis. Human inosine triphosphate pyrophosphatase (ITPA) hydrolyzes triphosphates of noncanonical purine bases (i.e., ITP, dITP, XTP, dXTP, or their mimic: 6-hydroxyaminopurine (HAP) deoxynucleoside triphosphate) and thus regulates nucleotide pools and protects cells from DNA damage. We demonstrate that the model purine base analog HAP induces DNA breaks in human cells and leads to elevation of levels of ITPA. A human polymorphic allele of the ITPA, 94C->A encodes for the enzyme with a P32T amino-acid change and leads to accumulation of nonhydrolyzed ITP. The polymorphism has been associated with adverse reaction to purine base-analog drugs. The level of both spontaneous and HAP-induced DNA breaks is elevated in the cell line with the ITPA P32T variant. The results suggested that human ITPA plays a pivotal role in the protection of DNA from noncanonical purine base analogs.
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Affiliation(s)
- Irina S-R Waisertreiger
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE 68198-6805, USA
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Xiong H, Xin HW, Wu XC, Li Q, Xiong L, Yu AR. Association between inosine triphosphate pyrophosphohydrolase deficiency and azathioprine-related adverse drug reactions in the Chinese kidney transplant recipients. Fundam Clin Pharmacol 2010; 24:393-400. [PMID: 19682085 DOI: 10.1111/j.1472-8206.2009.00770.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Azathioprine (AZA) is a thiopurine prodrug commonly used in patients with kidney transplantation. The aim of this study is to explore in patients with kidney transplantation whether AZA-related side effects can be explained by the inosine triphophate pyrophosphatase (ITPA) or thiopurine S-methyltransferase (TPMT) polymorphisms using both pheno-and genotyping. Erythrocyte ITPA and TPMT activity of 155 patients with kidney transplantation and AZA therapy was determined by HPLC. The frequencies of ITPA and TPMT polymorphisms were detected. Among 155 patients, three cases with zero activity were homozygote for 94C>A. The allele frequency of the 94C>A polymorphism was 0.12. Allele for the IVS2+21A>C mutation in the patients of this study was not found. Thirty-five cases had stopped azathioprine medication or were on reduced dose due to AZA-related side effects, including hematotoxicity (n = 12), hepatotoxicity (n = 18), gastrointestinal toxicity (n = 5, one patient developed hepatotoxicity simultaneously) and flu-like symptoms (n = 1). No statistical significant associations between ITPA 94C>A phenotype or genotype and AZA-related hematotoxicity or hepatotoxicity could be detected. However, five patients who developed gastrointestinal disturbance, two patients were homozygote for 94C>A and other three patients had 94C>A heterozygous allele. The patient who experienced flu-like symptoms were the remaining homozygote for 94C>A. This study demonstrates that ITPA activity reduced in patients with 94C>A mutation (P < 0.01). Patients with ITPA 94C>A homozygous allele are at high risk to develop AZA-related gastrointestinal toxicity and flu-like symptoms (P < 0.01). TPMT wild-type/ITPA variant (homozygote) is closely related to the AZA-induced side effects (P < 0.01).
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Affiliation(s)
- Hui Xiong
- Department of Clinical Pharmacology, Wuhan General Hospital of Guangzhou Command, Wuhan 430070, China
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Iyama T, Abolhassani N, Tsuchimoto D, Nonaka M, Nakabeppu Y. NUDT16 is a (deoxy)inosine diphosphatase, and its deficiency induces accumulation of single-strand breaks in nuclear DNA and growth arrest. Nucleic Acids Res 2010; 38:4834-43. [PMID: 20385596 PMCID: PMC2919730 DOI: 10.1093/nar/gkq249] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Nucleotides function in a variety of biological reactions; however, they can undergo various chemical modifications. Such modified nucleotides may be toxic to cells if not eliminated from the nucleotide pools. We performed a screen for modified-nucleotide binding proteins and identified human nucleoside diphosphate linked moiety X-type motif 16 (NUDT16) protein as an inosine triphosphate (ITP)/xanthosine triphosphate (XTP)/GTP-binding protein. Recombinant NUDT16 hydrolyzes purine nucleoside diphosphates to the corresponding nucleoside monophosphates. Among 29 nucleotides examined, the highest kcat/Km values were for inosine diphosphate (IDP) and deoxyinosine diphosphate (dIDP). Moreover, NUDT16 moderately hydrolyzes (deoxy)inosine triphosphate ([d]ITP). NUDT16 is mostly localized in the nucleus, and especially in the nucleolus. Knockdown of NUDT16 in HeLa MR cells caused cell cycle arrest in S-phase, reduced cell proliferation, increased accumulation of single-strand breaks in nuclear DNA as well as increased levels of inosine in RNA. We thus concluded that NUDT16 is a (deoxy)inosine diphosphatase that may function mainly in the nucleus to protect cells from deleterious effects of (d)ITP.
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Affiliation(s)
- Teruaki Iyama
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka, Japan
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