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Pagarin S, Bolognese A, Fornasaro S, Franzin M, Hofmann U, Lucafò M, Franca R, Schwab M, Stocco G, Decorti G, Bonifacio A. SERS spectroscopy as a tool for the study of thiopurine drug pharmacokinetics in a model of human B leukemia cells. Chem Biol Interact 2024; 387:110792. [PMID: 37944627 DOI: 10.1016/j.cbi.2023.110792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/23/2023] [Accepted: 11/02/2023] [Indexed: 11/12/2023]
Abstract
Thiopurine drugs are immunomodulatory antimetabolites relevant for pediatric patients characterized by dose-dependent adverse effects such as myelosuppression and hepatotoxicity, often related to inter-individual differences, involving the activity of important enzymes at the basis of their biotransformation, such as thiopurine S-methyltransferase (TPMT). Surface Enhanced Raman Scattering (SERS) spectroscopy is emerging as a bioanalytical tool and represents a valid alternative in terms of affordable costs, shorter analysis time and easier sample preparation in comparison to the most employed methods for pharmacokinetic analysis of drugs. The aim of this study is to investigate mercaptopurine and thioguanine pharmacokinetics by SERS in cell lysates of a B-lymphoblastoid cell line (NALM-6), that did (TPMT*1) or did not (MOCK) overexpress the wild-type form of TPMT as an in vitro cellular lymphocyte model to discriminate between cells with different levels of TPMT activity on the base of the amount of thioguanosine nucleotides (TGN) metabolites formed. SERS analysis of the cell lysates was carried out using SERS substrates constituted by Ag nanoparticles deposited on paper and parallel samples were used for quantification of thiopurine nucleotides with liquid chromatography-tandem mass spectrometry (LC-MS/MS). A direct SERS detection method has been set up that could be a tool to study thiopurine drug pharmacokinetics in in vitro cellular models to qualitatively discriminate between cells that do and do not overexpress the TPMT enzyme, as an alternative to other more laborious techniques. Results underlined decreased levels of TGN and increased levels of methylated metabolites when TPMT was overexpressed, both after mercaptopurine and thioguanine treatments. A strong positive correlation (Spearman's rank correlation coefficient rho = 0.96) exists between absolute quantification of TGMP (pmol/1 x 106 cells), obtained by LC-MS/MS, and SERS signal (intensity of TGN at 915 cm-1). In future studies, we aim to apply this method to investigate TPMT activity in pediatric patients' leukocytes.
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Affiliation(s)
- Sofia Pagarin
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Anna Bolognese
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Stefano Fornasaro
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Trieste, Italy
| | - Martina Franzin
- Institute for Maternal and Child Health, IRCCS "Burlo Garofolo", Trieste, Italy
| | - Ute Hofmann
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany; University of Tuebingen, Tuebingen, Germany
| | - Marianna Lucafò
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Raffaella Franca
- Institute for Maternal and Child Health, IRCCS "Burlo Garofolo", Trieste, Italy
| | - Matthias Schwab
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany; Departments of Clinical Pharmacology, and of Biochemistry and Pharmacy, University of Tuebingen, Tuebingen, Germany
| | - Gabriele Stocco
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy; Institute for Maternal and Child Health, IRCCS "Burlo Garofolo", Trieste, Italy.
| | - Giuliana Decorti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Alois Bonifacio
- Department of Engineering and Architecture, University of Trieste, Italy
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Gallardo-Cóndor J, Naranjo P, Atarihuana S, Coello D, Guevara-Ramírez P, Flores-Espinoza R, Burgos G, López-Cortés A, Cabrera-Andrade A. Population-Specific Distribution of TPMT Deficiency Variants and Ancestry Proportions in Ecuadorian Ethnic Groups: Towards Personalized Medicine. Ther Clin Risk Manag 2023; 19:1005-1018. [PMID: 38050617 PMCID: PMC10693761 DOI: 10.2147/tcrm.s432856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 11/06/2023] [Indexed: 12/06/2023] Open
Abstract
Purpose Thiopurine S-methyltransferase (TPMT) is an enzyme that metabolizes purine analogs, agents used in the treatment of acute lymphoblastic leukemia. Improper drug metabolism leads to toxicity in chemotherapy patients and reduces treatment effectiveness. TPMT variants associated with reduced enzymatic activity vary across populations. Therefore, studying these variants in heterogeneous populations, such as Ecuadorians, can help identify molecular causes of deficiency for this enzyme. Methods We sequenced the entire TPMT coding region in 550 Ecuadorian individuals from Afro-Ecuadorian, Indigenous, Mestizo, and Montubio ethnicities. Moreover, we conducted an ancestry analysis using 46 informative ancestry markers. Results We identified 8 single nucleotide variants in the coding region of TPMT. The most prevalent alleles were TPMT*3A, TPMT*3B, and TPMT*3C, with frequencies of 0.055, 0.012, and 0.015, respectively. Additionally, we found rare alleles TPMT*4 and TPMT*8 with frequencies of 0.005 and 0.003. Correlating the ancestry proportions with TPMT-deficient genotypes, we observed that the Native American ancestry proportion influenced the distribution of the TPMT*1/TPMT*3A genotype (OR = 5.977, p = 0.002), while the contribution of African ancestral populations was associated with the TPMT*1/TPMT*3C genotype (OR = 9.769, p = 0.003). The rates of TPMT-deficient genotypes observed in Mestizo (f = 0.121) and Indigenous (f = 0.273) groups provide evidence for the influence of Native American ancestry and the prevalence of the TPMT*3A allele. In contrast, although Afro-Ecuadorian groups demonstrate similar deficiency rates (f = 0.160), the genetic factors involved are associated with contributions from African ancestral populations, specifically the prevalent TPMT*3C allele. Conclusion The distribution of TPMT-deficient variants offers valuable insights into the populations under study, underscoring the necessity for genetic screening strategies to prevent thiopurine toxicity events among Latin American minority groups.
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Affiliation(s)
| | - Pablo Naranjo
- Facultad de Ingeniería y Ciencias Aplicadas, Universidad de Las Américas, Quito, Ecuador
| | - Sebastián Atarihuana
- Facultad de Ingeniería y Ciencias Aplicadas, Universidad de Las Américas, Quito, Ecuador
| | - Dayana Coello
- Laboratorios de Investigación, Universidad de Las Américas, Quito, Ecuador
| | - Patricia Guevara-Ramírez
- Centro de Investigación Genética y Genómica, Facultad de Ciencias de la Salud Eugenio Espejo, Universidad UTE, Quito, Ecuador
| | - Rodrigo Flores-Espinoza
- Laboratório de Diagnóstico por DNA (LDD), Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Germán Burgos
- One Health Research Group, Facultad de Medicina, Universidad de Las Américas, Quito, Ecuador
- Grupo de Medicina Xenomica, Instituto de Ciencias Forenses, Universidad de Santiago de Compostela, Satiago de Compostela, Spain
| | - Andrés López-Cortés
- Cancer Research Group (CRG), Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), Madrid, Spain
| | - Alejandro Cabrera-Andrade
- Escuela de Enfermería, Facultad de Ciencias de la Salud, Universidad de Las Américas, Quito, Ecuador
- Grupo de Bio-Quimioinformática, Universidad de Las Américas, Quito, Ecuador
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Watermeyer G, Awuku Y, Fredericks E, Epstein D, Setshedi M, Devani S, Mudombi W, Kassianides C, Katsidzira L. Challenges in the management of inflammatory bowel disease in sub-Saharan Africa. Lancet Gastroenterol Hepatol 2022; 7:962-972. [PMID: 35779534 DOI: 10.1016/s2468-1253(22)00048-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 06/15/2023]
Abstract
Inflammatory bowel disease (IBD) is generally considered a disease of high-income countries and is regarded as rare in sub-Saharan Africa. However, this assumption is almost certainly an underestimate, and the high burden of communicable diseases makes IBD in sub-Saharan Africa difficult to detect. Furthermore, some gastrointestinal infections can closely mimic IBD, contributing to delays in diagnosis and complicating therapeutic decision making. Constraints in endoscopic capacity alongside a scarcity of qualified diagnostic pathologists add to the difficulties. Implementing evidence-based guidelines recommended by international societies is challenging, mostly due to high costs and unavailability of medication. However, cost-effective approaches can still be implemented to manage IBD in sub-Saharan Africa as the predominant disease phenotype is mild-to-moderate ulcerative colitis, which often responds to treatment with basic medication. In this Series paper, we summarise the current management of IBD in sub-Saharan Africa and propose how it can be tailored to suit the epidemiological and socioeconomic specificities of the region. We also discuss measures required to address existing challenges, such as educating health-care workers about the diagnosis and management of IBD or improving endoscopic capacity.
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Affiliation(s)
- Gillian Watermeyer
- Department of Medicine, University of Cape Town Groote Schuur Hospital, Cape Town, South Africa.
| | - Yaw Awuku
- Department of Medicine, University of Health and Allied Sciences, Ho, Ghana
| | - Ernst Fredericks
- Department of Medicine, University of Stellenbosch, Cape Town, South Africa
| | | | - Mashiko Setshedi
- Department of Medicine, University of Cape Town Groote Schuur Hospital, Cape Town, South Africa
| | - Smita Devani
- Department of Medicine, Aga Khan University Hospital, Nairobi, Kenya
| | - Wisdom Mudombi
- Internal Medicine Unit, Faculty of Medicine and Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | | | - Leolin Katsidzira
- Internal Medicine Unit, Faculty of Medicine and Health Sciences, University of Zimbabwe, Harare, Zimbabwe
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4
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Zhou X, Cheng L, Wang Y, Gou H, Ju K, Lan T, Zhan T, Li G, Gu Y, Sun Y, Xu Y, Sun Y, Zhou Y, Li W. Effect of NUDT15 polymorphisms on early hematological safety of low-dose azathioprine in Chinese patients with pemphigus vulgaris: A prospective cohort study. J Dermatol 2021; 49:402-410. [PMID: 34866237 PMCID: PMC9299774 DOI: 10.1111/1346-8138.16265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 02/05/2023]
Abstract
Azathioprine (AZA) is the preferred immunosuppressant for treating pemphigus vulgaris (PV), with discontinuation mainly attributed to hematological adverse events (AE). Reportedly, nucleoside diphosphate‐linked moiety X‐type motif 15 (NUDT15) polymorphisms have been strongly associated with thiopurine‐induced leukopenia. To investigate hematological AE of low‐dose AZA based on NUDT15 genotypes among patients with PV, a prospective cohort study was conducted in patients with PV, followed‐up for the first 8 weeks after AZA administration. All patients were divided into wild homozygous and heterozygous NUDT15 groups. Both groups initiated AZA at low dose (50 mg/day) and continued with different dose‐escalating approaches. Bone marrow suppression was considered the principal outcome. Overall, 62 patients with PV were enrolled (48 in the wild homozygous NUDT15 group vs. 14 in the heterozygous NUDT15 group). Except for median maintenance doses of AZA, no statistically significant differences were observed between the two groups in terms of age, sex, white blood cells, neutrophil count, platelet count, hemoglobin level, median final doses of corticosteroids (mg prednisone equivalent), pemphigus disease area index, and anti‐desmoglein 1/3 autoantibodies. In both groups, patients presented similar hematological AE and treatment responses after administration of different low‐dose AZA treatment strategies. Low‐dose AZA based on NUDT15 genotypes can reduce the risk of early hematological AE among patients with PV.
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Affiliation(s)
- Xingli Zhou
- Department of Dermatology, Rare Diseases Center, West China Hospital, Sichuan University, Chengdu, China
| | - Liangliang Cheng
- School of Public Health, Sun Yat-Sen University, Guangzhou, China
| | - Yiyi Wang
- Department of Dermatology, Rare Diseases Center, West China Hospital, Sichuan University, Chengdu, China
| | - Hui Gou
- Department of Dermatology, Rare Diseases Center, West China Hospital, Sichuan University, Chengdu, China
| | - Ke Ju
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.,West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - TianJiao Lan
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Tongying Zhan
- Department of Dermatology, Rare Diseases Center, West China Hospital, Sichuan University, Chengdu, China
| | - GaoJie Li
- Department of Dermatology, Rare Diseases Center, West China Hospital, Sichuan University, Chengdu, China
| | - Yuanxia Gu
- Department of Dermatology, Rare Diseases Center, West China Hospital, Sichuan University, Chengdu, China
| | - Yeting Sun
- West China School of Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Yan Xu
- West China School of Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Yukun Sun
- West China School of Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Yanhong Zhou
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Wei Li
- Department of Dermatology, Rare Diseases Center, West China Hospital, Sichuan University, Chengdu, China
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5
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Franca R, Braidotti S, Stocco G, Decorti G. Understanding thiopurine methyltransferase polymorphisms for the targeted treatment of hematologic malignancies. Expert Opin Drug Metab Toxicol 2021; 17:1187-1198. [PMID: 34452592 DOI: 10.1080/17425255.2021.1974398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Thiopurine methyltransferase (TPMT) catalyzes the S-methylation of thiopurines (mercaptopurine (MP) and tioguanine (TG)), chemotherapeutic agents used in the treatment of acute lymphoblastic leukemia (ALL). Polymorphisms in TPMT gene encode diminished activity enzyme, enhancing accumulation of active metabolites, and partially explaining the inter-individual differences in patients' clinical response. AREAS COVERED This review gives an overview on TPMT gene and function, and discusses the pharmacogenomic implications of TPMT variants in the prevention of severe thiopurine-induced hematological toxicities and the less known implication on TG-induced sinusoidal obstruction syndrome. Additional genetic and non-genetic factors impairing TPMT activity are considered. Literature search was done in PubMed for English articles published since1990, and on PharmGKB. EXPERT OPINION To titrate thiopurines safely and effectively, achieve the right degree of lymphotoxic effect and avoid excessive myelosuppression, the optimal management will combine a preemptive TPMT genotyping to establish a safe initial dose with a close phenotypic monitoring of TPMT activity and/or of active metabolites during long-term treatment. Compared to current ALL protocols, replacement of TG by MP during reinduction phase in TPMT heterozygotes and novel individualized TG regimens in maintenance for TPMT wild-type subjects could be investigated to improve outcomes while avoiding risk of severe hepatotoxicity.
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Affiliation(s)
- R Franca
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - S Braidotti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - G Stocco
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - G Decorti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal & Child Health (I.r.c.c.s) Burlo Garofolo, Trieste, Italy
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6
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Alsous M, Yousef AM, Abdel Jalil M, Zawiah M, Yacoub S, Momani D, Gharabli A, Omar S, Rihani R. Genetic Polymorphism of Thiopurine S-methyltransferase in Children with Acute Lymphoblastic Leukemia in Jordan. Asian Pac J Cancer Prev 2018; 19:199-205. [PMID: 29373914 PMCID: PMC5844618 DOI: 10.22034/apjcp.2018.19.1.199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background and Aims: It has been demonstrated that homozygote and heterozygote mutant allele carriers for thiopurine S-methyltransferase (TPMT) are at high risk of developing myelosuppression after receiving standard doses of 6-mercaptopurine (6-MP). The aim of this study was to determine the frequency of TPMT deficient alleles in children with acute lymphoblastic leukemia (ALL) in Jordan and to compare it with other ethnic groups. Methods: We included 52 ALL childhood cases from King Hussein Cancer Research Center in Jordan. Genotyping of the rs1800460, rs1800462, and rs1142345 SNPs was performed by polymerase chain reaction (PCR) followed by sequencing. Comparisons were made with historical data for controls and for both volunteers and cases from other middle-eastern countries. Results: Mutant TPMT alleles were present in 3.8% (2/52) of patients. Allelic frequencies were 1.0% for both TPMT*B and TPMT*C. None of the patients were heterozygous or homozygous for TPMT*3A or TPMT *2. We did not find statistically significant differences in the distribution of mutant alleles between Jordan and other middle-eastern countries for both healthy volunteers or ALL patients. Conclusions: The overall frequency of TPMT mutant alleles was low and did not exhibit differences compared to other middle-eastern countries, including Jordanian studies assessing TPMT mutant alleles in healthy volunteers. The current results question the value of TPMT genotyping in the Jordanian population.
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Affiliation(s)
- Mervat Alsous
- Department of Clinical Pharmacy and Therapeutics, Faculty of Pharmacy, Applied Science Private University, Amman, Jordan.
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7
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Guillotin V, Galli G, Viallard JF. [Usefulness of thiopurine methyltransferase polymorphism study and metabolites measurement for patients treated by azathioprine]. Rev Med Interne 2018; 39:421-426. [PMID: 29370945 DOI: 10.1016/j.revmed.2017.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 12/18/2017] [Accepted: 12/28/2017] [Indexed: 11/18/2022]
Abstract
Azathioprine is widely used in internal medicine and frequently implicated in occurrence of adverse events. Among these adverse events the bone marrow suppression, a dose-related one, is the most serious because of is potential morbidity and mortality. Severe myelosuppression, associated with abnormal AZA metabolism, is linked to the thiopurine methyltransferase (TPMT) genetic polymorphism that results in a high variability of its activity with 89% of patients with a normal activity, 11% with an intermediate activity, and 0.3% with very low activity leading to a very high risk of bonne marrow suppression. TPMT status can be assessed prior to AZA treatment by measuring enzyme activity or genotyping techniques to identify patients for which the standard dose is not advisable. Furthermore, azathioprine metabolites monitoring is helpful for the follow up of patients, especially in therapeutic failure, to distinguish non-compliant patients from under-dosed, "shunters" or resistant patients.
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Affiliation(s)
- V Guillotin
- Laboratoire d'immunologie de l'hôpital Pellegrin, place Amélié-Raba-Léon, 33000 Bordeaux, France.
| | - G Galli
- Service de médecine interne et immunologie clinique, Hôpital Saint-André, rue Jean-Burguet, 33000 Bordeaux, France
| | - J-F Viallard
- Service de médecine interne, hôpital du Haut-Lévêque, avenue Magellan, 33604 Pessac, France
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8
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Clinical Practice Recommendations for the Management and Prevention of Cisplatin-Induced Hearing Loss Using Pharmacogenetic Markers. Ther Drug Monit 2017; 38:423-31. [PMID: 26960170 DOI: 10.1097/ftd.0000000000000298] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Currently no pharmacogenomics-based criteria exist to guide clinicians in identifying individuals who are at risk of hearing loss from cisplatin-based chemotherapy. This review summarizes findings from pharmacogenomic studies that report genetic polymorphisms associated with cisplatin-induced hearing loss and aims to (1) provide up-to-date information on new developments in the field, (2) provide recommendations for the use of pharmacogenetic testing in the prevention, assessment, and management of cisplatin-induced hearing loss in children and adults, and (3) identify knowledge gaps to direct and prioritize future research. These practice recommendations for pharmacogenetic testing in the context of cisplatin-induced hearing loss reflect a review and evaluation of recent literature, and are designed to assist clinicians in providing optimal clinical care for patients receiving cisplatin-based chemotherapy.
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Pharmacogénétique des immunosuppresseurs : état des connaissances et des pratiques – recommandations du Réseau national de pharmacogénétique (RNPGx). Therapie 2017; 72:269-284. [DOI: 10.1016/j.therap.2016.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/02/2016] [Indexed: 12/18/2022]
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10
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Woillard JB, Chouchana L, Picard N, Loriot MA. Pharmacogenetics of immunosuppressants: State of the art and clinical implementation - recommendations from the French National Network of Pharmacogenetics (RNPGx). Therapie 2017; 72:285-299. [PMID: 28318610 DOI: 10.1016/j.therap.2016.09.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/02/2016] [Indexed: 12/21/2022]
Abstract
Therapeutic drug monitoring is already widely used for immunosuppressive drugs due to their narrow therapeutic index. This article summarizes evidence reported in the literature regarding the pharmacogenetics of (i) immunosuppressive drugs used in transplantation and (ii) azathioprine used in chronic inflammatory bowel disease. The conditions of use of currently available major pharmacogenetic tests are detailed and recommendations are provided based on a scale established by the RNPGx scoring tests as "essential", "advisable" and "potentially useful". Other applications for which the level of evidence is still debated are also discussed.
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Affiliation(s)
- Jean-Baptiste Woillard
- Service de pharmacologie, toxicologie et pharmacovigilance, centre de biologie et de recherche en santé, CHU de Limoges, 87042 Limoges, France; Université de Limoges UMR_S850, 87000 Limoges, France.
| | - Laurent Chouchana
- Service de pharmacologie, hôpital Cochin, Assistance publique-Hôpitaux de Paris (AP-HP), 75014 Paris, France
| | - Nicolas Picard
- Service de pharmacologie, toxicologie et pharmacovigilance, centre de biologie et de recherche en santé, CHU de Limoges, 87042 Limoges, France; Université de Limoges UMR_S850, 87000 Limoges, France
| | - Marie-Anne Loriot
- Inserm UMR_S1147, centre universitaire des Saints-Pères, 75006 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; Service de biochimie, hôpital européen Georges-Pompidou, Assistance publique-Hôpitaux de Paris (AP-HP), 75015 Paris, France
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Abaji R, Krajinovic M. Current perspective on pediatric pharmacogenomics. Expert Opin Drug Metab Toxicol 2016; 12:363-5. [PMID: 26799591 DOI: 10.1517/17425255.2016.1145656] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Rachid Abaji
- a Research Center, CHU Sainte-Justine , University of Montreal , Montreal , Quebec , Canada.,b Department of Pharmacology , University of Montreal , Montreal , Quebec , Canada
| | - Maja Krajinovic
- a Research Center, CHU Sainte-Justine , University of Montreal , Montreal , Quebec , Canada.,c Departments of Pediatrics and Pharmacology , University of Montreal , Montreal , Quebec , Canada
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12
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Roberts RL, Barclay ML. Update on thiopurine pharmacogenetics in inflammatory bowel disease. Pharmacogenomics 2015; 16:891-903. [PMID: 26067482 DOI: 10.2217/pgs.15.29] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Azathioprine and 6-mercaptopurine remain pivotal therapies for the maintenance of disease remission in patients with Crohn's disease and ulcerative colitis. While thiopurine S-methyltransferase deficiency was the first pharmacogenetic phenomenon to be recognized to influence thiopurine toxicity and reliably predict leukopenia, it does not predict other adverse effects, nor does it explain most cases of thiopurine resistance. In recent years, a number of other genetic polymorphisms have received increasing attention in the literature. In particular, SNPs in NUDT15 and in the class II HLA locus have been shown to predict thiopurine-related leukopenia and pancreatitis. The aim of this review is to provide a concise update of genetic variability which may influence patient response to azathioprine and 6-mercaptopurine.
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Affiliation(s)
- Rebecca L Roberts
- Department of Surgical Sciences, Dunedin School of Medicine, PO Box 56, Dunedin, New Zealand
| | - Murray L Barclay
- Department of Medicine, University of Otago Christchurch, PO Box 4345, Christchurch, New Zealand.,Department of Gastroenterology, Christchurch Hospital, Private Bag 4710, Christchurch, New Zealand
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13
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Identification of a novel thiopurine S-methyltransferase allele (TPMT*37). Pharmacogenet Genomics 2014; 24:320-3. [PMID: 24710034 DOI: 10.1097/fpc.0000000000000049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Thiopurine S-methyltransferase (TPMT) is a key enzyme in the methylation of the thiopurine drugs azathioprine and 6-mercaptopurine. TPMT is subject to genetic polymorphism that results in a trimodal distribution of enzyme activity. All poor methylators (PMs) and 30-60% of intermediate methylators develop potentially life-threatening myelosuppression on standard doses of azathioprine and 6-mercaptopurine because of excess production of the thioguanine nucleotides (6-TGNs). Over 95% of PMs are explained by the alleles TPMT*2 and TPMT*3, whereas one in 20 intermediate methylators are heterozygous for a novel PM allele. In this brief report, we describe the identification of a novel allele (TPMT*37) in a Caucasian male who had a red blood cell TPMT activity of 8.9 U/ml (reference range: 9.3-17.6 U/ml). TPMT*37 introduces a premature stop codon at position 216, resulting in loss of the last 29 amino acid residues from the C terminal of the TPMT protein.
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Almoguera B, Vazquez L, Connolly JJ, Bradfield J, Sleiman P, Keating B, Hakonarson H. Imputation of TPMT defective alleles for the identification of patients with high-risk phenotypes. Front Genet 2014; 5:96. [PMID: 24860591 PMCID: PMC4026736 DOI: 10.3389/fgene.2014.00096] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/04/2014] [Indexed: 12/14/2022] Open
Abstract
Background: The activity of thiopurine methyltransferase (TPMT) is subject to genetic variation. Loss-of-function alleles are associated with various degrees of myelosuppression after treatment with thiopurine drugs, thus genotype-based dosing recommendations currently exist. The aim of this study was to evaluate the potential utility of leveraging genomic data from large biorepositories in the identification of individuals with TPMT defective alleles. Material and methods: TPMT variants were imputed using the 1000 Genomes Project reference panel in 87,979 samples from the biobank at The Children's Hospital of Philadelphia. Population ancestry was determined by principal component analysis using HapMap3 samples as reference. Frequencies of the TPMT imputed alleles, genotypes and the associated phenotype were determined across the different populations. A sample of 630 subjects with genotype data from Sanger sequencing (N = 59) and direct genotyping (N = 583) (12 samples overlapping in the two groups) was used to check the concordance between the imputed and observed genotypes, as well as the sensitivity, specificity and positive and negative predictive values of the imputation. Results: Two SNPs (rs1800460 and rs1142345) that represent three TPMT alleles (*3A, *3B, and *3C) were imputed with adequate quality. Frequency for the associated enzyme activity varied across populations and 89.36–94.58% were predicted to have normal TPMT activity, 5.3–10.31% intermediate and 0.12–0.34% poor activities. Overall, 98.88% of individuals (623/630) were correctly imputed into carrying no risk alleles (553/553), heterozygous (45/46) and homozygous (25/31). Sensitivity, specificity and predictive values of imputation were over 90% in all cases except for the sensitivity of imputing homozygous subjects that was 80.64%. Conclusion: Imputation of TPMT alleles from existing genomic data can be used as a first step in the screening of individuals at risk of developing serious adverse events secondary to thiopurine drugs.
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Affiliation(s)
- Berta Almoguera
- Center for Applied Genomics, The Children's Hospital of Philadelphia Philadelphia, PA, USA
| | - Lyam Vazquez
- Center for Applied Genomics, The Children's Hospital of Philadelphia Philadelphia, PA, USA
| | - John J Connolly
- Center for Applied Genomics, The Children's Hospital of Philadelphia Philadelphia, PA, USA
| | - Jonathan Bradfield
- Center for Applied Genomics, The Children's Hospital of Philadelphia Philadelphia, PA, USA
| | - Patrick Sleiman
- Center for Applied Genomics, The Children's Hospital of Philadelphia Philadelphia, PA, USA ; Department of Pediatrics, University of Pennsylvania Perelman School of Medicine Philadelphia, PA, USA
| | - Brendan Keating
- Center for Applied Genomics, The Children's Hospital of Philadelphia Philadelphia, PA, USA ; Department of Pediatrics, University of Pennsylvania Perelman School of Medicine Philadelphia, PA, USA
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children's Hospital of Philadelphia Philadelphia, PA, USA ; Department of Pediatrics, University of Pennsylvania Perelman School of Medicine Philadelphia, PA, USA
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Abstract
The drug-metabolizing enzyme thiopurine methyltransferase (TPMT) has become one of the best examples of pharmacogenomics to be translated into routine clinical practice. TPMT metabolizes the thiopurines 6-mercaptopurine, 6-thioguanine, and azathioprine, drugs that are widely used for treatment of acute leukemias, inflammatory bowel diseases, and other disorders of immune regulation. Since the discovery of genetic polymorphisms in the TPMT gene, many sequence variants that cause a decreased enzyme activity have been identified and characterized. Increasingly, to optimize dose, pretreatment determination of TPMT status before commencing thiopurine therapy is now routine in many countries. Novel TPMT sequence variants are currently numbered sequentially using PubMed as a source of information; however, this has caused some problems as exemplified by two instances in which authors' articles appeared on PubMed at the same time, resulting in the same allele numbers given to different polymorphisms. Hence, there is an urgent need to establish an order and consensus to the numbering of known and novel TPMT sequence variants. To address this problem, a TPMT nomenclature committee was formed in 2010, to define the nomenclature and numbering of novel variants for the TPMT gene. A website (http://www.imh.liu.se/tpmtalleles) serves as a platform for this work. Researchers are encouraged to submit novel TPMT alleles to the committee for designation and reservation of unique allele numbers. The committee has decided to renumber two alleles: nucleotide position 106 (G>A) from TPMT*24 to TPMT*30 and position 611 (T>C, rs79901429) from TPMT*28 to TPMT*31. Nomenclature for all other known alleles remains unchanged.
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Roberts RL, Barclay ML. Current relevance of pharmacogenetics in immunomodulation treatment for Crohn's disease. J Gastroenterol Hepatol 2012; 27:1546-54. [PMID: 22741564 DOI: 10.1111/j.1440-1746.2012.07220.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
No drug therapy is completely risk free, and the costs associated with non-response and adverse effects can exceed the cost of the therapy. The ultimate goal of pharmacogenetic research is to find robust genetic predictors of drug response that enable the development of prospective genetic tests to reliably identify patients at risk of non-response or of developing an adverse effect prior to the drug being prescribed. Currently, thiopurine S-methyltransferase (TPMT) deficiency is the only pharmacogenetic factor that is prospectively assessed before azathioprine or 6-mercaptopurine immunomodulation is commenced in patients with Crohn's disease (CD). As yet no other inherited determinant of drug response has made the transition from bench to bedside for the management of this disease. In this review we summarize what is known about TPMT deficiency and explore whether there is evidence to support a role of other genetic polymorphisms in predicting the response of CD patients to thiopurine drugs, methotrexate, and anti-tumor necrosis factor α (TNFα) therapy.
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Affiliation(s)
- Rebecca L Roberts
- Department of Surgical Sciences, Dunedin School of Medicine, Dunedin, New Zealand.
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17
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Milone MC. Therapeutic Drug Monitoring of Selected Anticancer Drugs. Ther Drug Monit 2012. [DOI: 10.1016/b978-0-12-385467-4.00014-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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19
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Hakooz N, Arafat T, Payne D, Ollier W, Pushpakom S, Andrews J, Newman W. Genetic analysis of thiopurine methyltransferase polymorphism in the Jordanian population. Eur J Clin Pharmacol 2010; 66:999-1003. [PMID: 20521035 DOI: 10.1007/s00228-010-0826-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 03/31/2010] [Indexed: 01/26/2023]
Abstract
UNLABELLED This study provides the first analysis of the TPMT mutant allele frequency in a sample of the Jordanian population and indicates that TPMT*3A is the most common allele in Jordanian subjects. PURPOSE thiopurine methyltransferase TPMT catalyses the S-methylation of thiopurine drugs such as 6-mercaptopurine, 6-thioguanine, and azathiopurine. Thiopurine methyltransferase (TPMT) polymorphisms are the major determinants of interindividual differences in the severe haematological toxicity of 6-mercaptopurine. Several variants in the TPMT gene have been identified that correlate with a low activity phenotype. Four variant alleles, TPMT*2, TPMT*3A, TPMT*3B and TPMT*3C, are responsible for over 80% of the low or undetectable enzyme activity. The allelic frequency of TPMT variants has been established in many populations. METHODS In this study, the frequencies of four (TPMT*2, TPMT*3A, TPMT*3B and TPMT*3C) variants were investigated in 169 healthy Jordanian men (18-45 years of age). Single nucleotide polymorphisms (SNPs) were genotyped using the Sequenom MassARRAY technology (Sequenom; San Diego, CA, USA). RESULTS TPMT*3A and TPMT*3C were the only deficiency alleles detected in the Jordanian population with an allele frequency of 0.59% and 0.30% respectively. The TPMT*3A allele frequency is found to be lower than in the European Caucasian population. CONCLUSION TPMT*3A and TPMT*3C were the only deficiency alleles detected in the Jordanian population with an allele frequency of 0.59% and 0.30% respectively. The TPMT*3A allele frequency is found to be lower than in the European Caucasian population.
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Affiliation(s)
- Nancy Hakooz
- Faculty of Pharmacy, University of Jordan, Amman 11942, Jordan,
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Improving pharmacovigilance in Europe: TPMT genotyping and phenotyping in the UK and Spain. Eur J Hum Genet 2009; 17:991-8. [PMID: 19223932 DOI: 10.1038/ejhg.2009.10] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Thiopurine S-methyltransferase (TPMT) is the rate-limiting step in the conversion of thiopurine drugs including azathioprine (AZA) to inactive metabolites. Heritable deficiency of TPMT activity increases risk for adverse events, most notably, myelosuppression leading to leukopenia and neutropenic sepsis. The reported European Commission study was undertaken to identify current evidence for the clinical utility of testing for TPMT status and extent of uptake, by either genotyping or phenotyping, in the clinical setting. Data presented here for the UK and Spain indicate that there has been a considerable increase in the uptake of TPMT testing in recent years. There are some data that support routine TPMT testing before AZA prescribing for reducing AZA-related adverse events. Key data include evidence in favor of TPMT testing in addition to the current practice of routine monitoring for reducing the number of AZA-related episodes of myelosuppression, averting deaths from neutropenic sepsis and improving health-related quality of life. Further data are needed for determining the cost-effectiveness of routine TPMT testing.
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Abstract
Thiopurine methyltransferase (TPMT) activity shows significant interindividual variation, with approximately 90% of individuals having high (wild-type) activity, 10% with intermediate activity, and 0.3% with low activity. Low and intermediate TPMT activity leads to toxicity from mercaptopurine and the need for dose reduction. Common variants in the TPMT gene have a strong association with mercaptopurine toxicity. However, recent research has shown that genetic contribution to mercaptopurine toxicity is more complex, possibly involving other genes, in particular ITPA, which encodes inosine triphosphate pyrophosphatase.
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Roberts RL, Gearry RB, Kennedy MA, Barclay ML. Beyond TPMT: genetic influences on thiopurine drug responses in inflammatory bowel disease. Per Med 2008; 5:233-248. [PMID: 29783500 DOI: 10.2217/17410541.5.3.233] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Azathioprine and 6-mercaptopurine are widely used in the management of inflammatory bowel disease (IBD). However, approximately 25% of IBD patients experience toxicity, and up to 10% show resistance to these thiopurine drugs. The importance of genetic variability in determining thiopurine toxicity was first recognized over 25 years ago with the discovery of the thiopurine S-methyltransferase (TPMT) polymorphism and the occurrence of azathioprine-induced myelosuppression in TPMT-deficient patients. In the intervening period, TPMT has become the foremost example of pharmacogenetics, and TPMT deficiency represents one of the few pharmacogenetic phenomena that have successfully made the transition from the research laboratory to diagnostics. While TPMT activity predicts some cases of myelosuppression, deficiency in this enzyme is neither predictive of other adverse drug reactions, nor resistance to thiopurine therapy. As myelosuppression only accounts for approximately 2.5% of adverse reactions in IBD patients, researchers are increasingly turning their attention to other enzymes involved in thiopurine metabolism to find molecular explanations for intolerance and resistance to azathioprine and 6-mercaptopurine. In this review, we summarize the current state of knowledge with regards to TPMT, and also explore genetic variability, beyond TPMT, that may contribute to thiopurine response in IBD patients.
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Affiliation(s)
| | - Richard B Gearry
- Department of Medicine, University of Otago, Christchurch 8140, New Zealand.,Department of Gastroenterology, Christchurch Hospital, Private Bag 151, Christchurch 8140, New Zealand
| | - Martin A Kennedy
- Department of Pathology, University of Otago, Christchurch 8140, New Zealand
| | - Murray L Barclay
- Department of Medicine, University of Otago, Christchurch 8140, New Zealand.,Department of Gastroenterology, Christchurch Hospital, Private Bag 151, Christchurch 8140, New Zealand
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Cooper SC, Ford LT, Berg JD, Lewis MJV. Ethnic variation of thiopurineS-methyltransferase activity: a large, prospective population study. Pharmacogenomics 2008; 9:303-9. [PMID: 18303966 DOI: 10.2217/14622416.9.3.303] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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