1
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Mu H, Ye L, Wang B. Detailed resume of S-methyltransferases: Categories, structures, biological functions and research advancements in related pathophysiology and pharmacotherapy. Biochem Pharmacol 2024; 226:116361. [PMID: 38876259 DOI: 10.1016/j.bcp.2024.116361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/19/2024] [Accepted: 06/10/2024] [Indexed: 06/16/2024]
Abstract
Methylation is a vital chemical reaction in the metabolism of many drugs, neurotransmitters, hormones, and exogenous compounds. Among them, S-methylation plays a significant role in the biotransformation of sulfur-containing compounds, particularly chemicals with sulfhydryl groups. Currently, only three S-methyltransferases have been reported: thiopurine methyltransferase (TPMT), thiol methyltransferase (TMT), and thioether methyltransferase (TEMT). These enzymes are involved in various biological processes such as gene regulation, signal transduction, protein repair, tumor progression, and biosynthesis and degradation reactions in animals, plants, and microorganisms. Furthermore, they play pivotal roles in the metabolic pathways of essential drugs and contribute to the advancement of diseases such as tumors. This paper reviews the research progress on relevant structural features, metabolic mechanisms, inhibitor development, and influencing factors (gene polymorphism, S-adenosylmethionine level, race, sex, age, and disease) of S-methyltransferases. We hope that a better comprehension of S-methyltransferases will help to provide a reference for the development of novel strategies for related disorders and improve long-term efficacy.
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Affiliation(s)
- Hongfei Mu
- Department of Drug Metabolism, Beijing Key Laboratory of Non-Clinical Drug Metabolism and PK/PD Study, State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China.
| | - Lisha Ye
- Department of Drug Metabolism, Beijing Key Laboratory of Non-Clinical Drug Metabolism and PK/PD Study, State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China.
| | - Baolian Wang
- Department of Drug Metabolism, Beijing Key Laboratory of Non-Clinical Drug Metabolism and PK/PD Study, State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China.
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2
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Neti SS, Wang B, Iwig DF, Onderko EL, Booker SJ. Enzymatic Fluoromethylation Enabled by the S-Adenosylmethionine Analog Te-Adenosyl- L-(fluoromethyl)homotellurocysteine. ACS CENTRAL SCIENCE 2023; 9:905-914. [PMID: 37252363 PMCID: PMC10214534 DOI: 10.1021/acscentsci.2c01385] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Indexed: 05/31/2023]
Abstract
Fluoromethyl, difluoromethyl, and trifluoromethyl groups are present in numerous pharmaceuticals and agrochemicals, where they play critical roles in the efficacy and metabolic stability of these molecules. Strategies for late-stage incorporation of fluorine-containing atoms in molecules have become an important area of organic and medicinal chemistry as well as synthetic biology. Herein, we describe the synthesis and use of Te-adenosyl-L-(fluoromethyl)homotellurocysteine (FMeTeSAM), a novel and biologically relevant fluoromethylating agent. FMeTeSAM is structurally and chemically related to the universal cellular methyl donor S-adenosyl-L-methionine (SAM) and supports the robust transfer of fluoromethyl groups to oxygen, nitrogen, sulfur, and some carbon nucleophiles. FMeTeSAM is also used to fluoromethylate precursors to oxaline and daunorubicin, two complex natural products that exhibit antitumor properties.
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Affiliation(s)
- Syam Sundar Neti
- Department
of Chemistry, Department of Biochemistry and Molecular Biology, and Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Bo Wang
- Department
of Chemistry, Department of Biochemistry and Molecular Biology, and Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - David F. Iwig
- Department
of Chemistry, Department of Biochemistry and Molecular Biology, and Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Elizabeth L. Onderko
- Department
of Chemistry, Department of Biochemistry and Molecular Biology, and Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
| | - Squire J. Booker
- Department
of Chemistry, Department of Biochemistry and Molecular Biology, and Howard Hughes
Medical Institute, The Pennsylvania State
University, University
Park, Pennsylvania 16802, United States
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3
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Alonso‐Fernandes E, Fernández‐Llamosas H, Cano I, Serrano‐Pelejero C, Castro L, Díaz E, Carmona M. Enhancing tellurite and selenite bioconversions by overexpressing a methyltransferase from
Aromatoleum
sp. CIB. Microb Biotechnol 2022; 16:915-930. [PMID: 36366868 PMCID: PMC10128142 DOI: 10.1111/1751-7915.14162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/21/2022] [Accepted: 10/09/2022] [Indexed: 11/13/2022] Open
Abstract
Pollution by metalloids, e.g., tellurite and selenite, is of serious environmental concern and, therefore, there is an increasing interest in searching for ecologically friendly solutions for their elimination. Some microorganisms are able to reduce toxic tellurite/selenite into less toxic elemental tellurium (Te) and selenium (Se). Here, we describe the use of the environmentally relevant β-proteobacterium Aromatoleum sp. CIB as a platform for tellurite elimination. Aromatoleum sp. CIB was shown to tolerate 0.2 and 0.5 mM tellurite at aerobic and anaerobic conditions, respectively. Furthermore, the CIB strain was able to reduce tellurite into elemental Te producing rod-shaped Te nanoparticles (TeNPs) of around 200 nm length. A search in the genome of Aromatoleum sp. CIB revealed the presence of a gene, AzCIB_0135, which encodes a new methyltransferase that methylates tellurite and also selenite. AzCIB_0135 orthologs are widely distributed in bacterial genomes. The overexpression of the AzCIB_0135 gene both in Escherichia coli and Aromatoleum sp. CIB speeds up tellurite and selenite removal, and it enhances the production of rod-shaped TeNPs and spherical Se nanoparticles (SeNPs), respectively. Thus, the overexpression of a methylase becomes a new genetic strategy to optimize bacterial catalysts for tellurite/selenite bioremediation and for the programmed biosynthesis of metallic nanoparticles of biotechnological interest.
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Affiliation(s)
- Elena Alonso‐Fernandes
- Microbial and Plant Biotechnology Department Centro de Investigaciones Biológicas Margarita Salas‐CSIC Madrid Spain
| | - Helga Fernández‐Llamosas
- Microbial and Plant Biotechnology Department Centro de Investigaciones Biológicas Margarita Salas‐CSIC Madrid Spain
| | - Irene Cano
- Microbial and Plant Biotechnology Department Centro de Investigaciones Biológicas Margarita Salas‐CSIC Madrid Spain
| | - Cristina Serrano‐Pelejero
- Microbial and Plant Biotechnology Department Centro de Investigaciones Biológicas Margarita Salas‐CSIC Madrid Spain
| | - Laura Castro
- Department of Material Science and Metallurgical Engineering, Facultad de Químicas Universidad Complutense de Madrid Madrid Spain
| | - Eduardo Díaz
- Microbial and Plant Biotechnology Department Centro de Investigaciones Biológicas Margarita Salas‐CSIC Madrid Spain
| | - Manuel Carmona
- Microbial and Plant Biotechnology Department Centro de Investigaciones Biológicas Margarita Salas‐CSIC Madrid Spain
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4
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Majumdar S, Gupta U, Chinnasamy HV, Laxmipathy S, Matheshwaran S. Zn 2+-Induced Conformational Change Affects the SAM Binding in a Mycobacterial SAM-Dependent Methyltransferase. ACS OMEGA 2022; 7:35901-35910. [PMID: 36249403 PMCID: PMC9558604 DOI: 10.1021/acsomega.2c04555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
Zinc is a cofactor for enzymes involved in DNA replication, peptidoglycan hydrolysis, and pH maintenance, in addition to the transfer of the methyl group to thiols. Here, we discovered a new role of Zn2+ as an inhibitor for S-adenosyl methionine (SAM) binding in a mycobacterial methyltransferase. Rv1377c is annotated as a putative methyltransferase that is upregulated upon the mitomycin C treatment of Mycobacterium tuberculosis. Sequence analysis and experimental validation allowed the identification of distinct motifs responsible for SAM binding. A detailed analysis of the AlphaFold-predicted structure of Rv1377c revealed four cysteine residues capable of coordinating a Zn2+ ion located in proximity to the SAM-binding site. Further, experimental studies showed distinct conformational changes upon Zn2+ binding to the protein, which compromised its ability to bind SAM. This is the first report wherein Zn2+-driven conformational changes in a methyltransferase undermines its ability to bind SAM.
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Affiliation(s)
- Soneya Majumdar
- Department
of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh India
| | - Umang Gupta
- Department
of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh India
| | - Hariharan V. Chinnasamy
- Department
of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh India
| | - Sathishkumar Laxmipathy
- Department
of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh India
| | - Saravanan Matheshwaran
- Department
of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh India
- Center
for Environmental Science and Engineering, Indian Institute of Technology, Kanpur 208016, Uttar
Pradesh India
- Mehta
Family Centre for Engineering in Medicine, Indian Institute of Technology, Kanpur 208016, Uttar
Pradesh India
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5
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Insights into methionine S-methylation in diverse organisms. Nat Commun 2022; 13:2947. [PMID: 35618717 PMCID: PMC9135737 DOI: 10.1038/s41467-022-30491-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/02/2022] [Indexed: 12/04/2022] Open
Abstract
Dimethylsulfoniopropionate (DMSP) is an important marine anti-stress compound, with key roles in global nutrient cycling, chemotaxis and, potentially, climate regulation. Recently, diverse marine Actinobacteria, α- and γ-proteobacteria were shown to initiate DMSP synthesis via the methionine (Met) S-methyltransferase enzyme (MmtN), generating S-methyl-Met (SMM). Here we characterize a roseobacterial MmtN, providing structural and mechanistic insights into this DMSP synthesis enzyme. We propose that MmtN uses the proximity and desolvation mechanism for Met S-methylation with two adjacent MmtN monomers comprising the Met binding site. We also identify diverse functional MmtN enzymes in potentially symbiotic archaeal Candidatus Woesearchaeota and Candidate Phyla Radiation (CPR) bacteria, and the animalcule Adineta steineri, not anticipated to produce SMM and/or DMSP. These diverse MmtN enzymes, alongside the larger plant MMT enzyme with an N-terminus homologous to MmtN, likely utilize the same proximity and desolvation mechanism. This study provides important insights into the catalytic mechanism of SMM and/or DMSP production, and proposes roles for these compounds in secondary metabolite production, and SMM cycling in diverse organisms and environments. S-methyl methionine (SMM) is a key molecule in production of dimethylsulfoniopropionate (DMSP), an important marine anti-stress compound, with roles in global nutrient cycling. Here, the authors determine the mechanism of SMM synthesis and uncover unexpected roles for SMM in archaea, CPR bacteria and animals.
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6
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Lazarević S, Đanic M, Al-Salami H, Mooranian A, Mikov M. Gut Microbiota Metabolism of Azathioprine: A New Hallmark for Personalized Drug-Targeted Therapy of Chronic Inflammatory Bowel Disease. Front Pharmacol 2022; 13:879170. [PMID: 35450035 PMCID: PMC9016117 DOI: 10.3389/fphar.2022.879170] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/16/2022] [Indexed: 12/16/2022] Open
Abstract
Despite the growing number of new drugs approved for the treatment of inflammatory bowel disease (IBD), the long-term clinical use of thiopurine therapy and the well-known properties of conventional drugs including azathioprine have made their place in IBD therapy extremely valuable. Despite the fact that thiopurine S-methyltransferase (TPMT) polymorphism has been recognized as a major cause of the interindividual variability in the azathioprine response, recent evidence suggests that there might be some yet unknown causes which complicate dosing strategies causing either failure of therapy or toxicity. Increasing evidence suggests that gut microbiota, with its ability to release microbial enzymes, affects the pharmacokinetics of numerous drugs and subsequently drastically alters clinical effectiveness. Azathioprine, as an orally administered drug which has a complex metabolic pathway, is the prime illustrative candidate for such microbial metabolism of drugs. Comprehensive databases on microbial drug-metabolizing enzymes have not yet been generated. This study provides insights into the current evidence on microbiota-mediated metabolism of azathioprine and systematically accumulates findings of bacteria that possess enzymes required for the azathioprine biotransformation. Additionally, it proposes concepts for the identification of gut bacteria species responsible for the metabolism of azathioprine that could aid in the prediction of dose-response effects, complementing pharmacogenetic approaches already applied in the optimization of thiopurine therapy of IBD. It would be of great importance to elucidate to what extent microbiota-mediated metabolism of azathioprine contributes to the drug outcomes in IBD patients which could facilitate the clinical implementation of novel tools for personalized thiopurine treatment of IBD.
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Affiliation(s)
- Slavica Lazarević
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Maja Đanic
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Hani Al-Salami
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Armin Mooranian
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,Hearing Therapeutics Department, Ear Science Institute Australia, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia
| | - Momir Mikov
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
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7
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Intestinal Microbiota-Mediated Biotransformations Alter the Pharmacokinetics of the Major Metabolites of Azathioprine in Rats after Oral Administration. Drug Metab Pharmacokinet 2022; 45:100458. [DOI: 10.1016/j.dmpk.2022.100458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/24/2022] [Accepted: 03/11/2022] [Indexed: 11/22/2022]
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8
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Franzin M, Stefančič K, Lucafò M, Decorti G, Stocco G. Microbiota and Drug Response in Inflammatory Bowel Disease. Pathogens 2021; 10:211. [PMID: 33669168 PMCID: PMC7919657 DOI: 10.3390/pathogens10020211] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 02/06/2023] Open
Abstract
A mutualistic relationship between the composition, function and activity of the gut microbiota (GM) and the host exists, and the alteration of GM, sometimes referred as dysbiosis, is involved in various immune-mediated diseases, including inflammatory bowel disease (IBD). Accumulating evidence suggests that the GM is able to influence the efficacy of the pharmacological therapy of IBD and to predict whether individuals will respond to treatment. Additionally, the drugs used to treat IBD can modualate the microbial composition. The review aims to investigate the impact of the GM on the pharmacological therapy of IBD and vice versa. The GM resulted in an increase or decrease in therapeutic responses to treatment, but also to biotransform drugs to toxic metabolites. In particular, the baseline GM composition can help to predict if patients will respond to the IBD treatment with biologic drugs. On the other hand, drugs can affect the GM by incrementing or reducing its diversity and richness. Therefore, the relationship between the GM and drugs used in the treatment of IBD can be either beneficial or disadvantageous.
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Affiliation(s)
- Martina Franzin
- Department of Medicine, Surgery and Health Sciences, University of Trieste, 34127 Trieste, Italy;
| | - Katja Stefančič
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (K.S.); (G.S.)
| | - Marianna Lucafò
- Institute for Maternal and Child Health—IRCCS “Burlo Garofolo”, 34137 Trieste, Italy;
| | - Giuliana Decorti
- Department of Medicine, Surgery and Health Sciences, University of Trieste, 34127 Trieste, Italy;
- Institute for Maternal and Child Health—IRCCS “Burlo Garofolo”, 34137 Trieste, Italy;
| | - Gabriele Stocco
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (K.S.); (G.S.)
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9
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Mariasina SS, Chang CF, Petrova OA, Efimov SV, Klochkov VV, Kechko OI, Mitkevich VA, Sergiev PV, Dontsova OA, Polshakov VI. Williams-Beuren syndrome-related methyltransferase WBSCR27: cofactor binding and cleavage. FEBS J 2020; 287:5375-5393. [PMID: 32255258 DOI: 10.1111/febs.15320] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/20/2020] [Accepted: 03/30/2020] [Indexed: 11/28/2022]
Abstract
Williams-Beuren syndrome, characterized by numerous physiological and mental problems, is caused by the heterozygous deletion of chromosome region 7q11.23, which results in the disappearance of 26 protein-coding genes. Protein WBSCR27 is a product of one of these genes whose biological function has not yet been established and for which structural information has been absent until now. Using NMR, we investigated the structural and functional properties of murine WBSCR27. For protein in the apo form and in a complex with S-(5'-adenosyl)-l-homocysteine (SAH), a complete NMR resonance assignment has been obtained and the secondary structure has been determined. This information allows us to attribute WBSCR27 to Class I methyltransferases. The interaction of WBSCR27 with the cofactor S-(5'-adenosyl)-l-methionine (SAM) and its metabolic products - SAH, 5'-deoxy-5'-methylthioadenosine (MTA) and 5'-deoxyadenosine (5'dAdo) - was studied by NMR and isothermal titration calorimetry. SAH binds WBSCR27 much tighter than SAM, leaving open the question of cofactor turnover in the methylation reaction. One possible answer to this question is the presence of weak but detectable nucleosidase activity for WBSCR27. We found that the enzyme catalyses the cleavage of the adenine moiety from SAH, MTA and 5'dAdo, similar to the action of bacterial SAH/MTA nucleosidases. We also found that the binding of SAM or SAH causes a significant change in the structure of WBSCR27 and in the conformational mobility of the protein fragments, which can be attributed to the substrate recognition site. This indicates that the binding of the cofactor modulates the folding of the substrate-recognizing region of the enzyme.
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Affiliation(s)
| | - Chi-Fon Chang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Sergey V Efimov
- NMR Laboratory, Institute of Physics, Kazan Federal University, Russia
| | | | - Olga I Kechko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Vladimir A Mitkevich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Petr V Sergiev
- M.V. Lomonosov Moscow State University, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Olga A Dontsova
- M.V. Lomonosov Moscow State University, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
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10
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Lucafò M, Franzin M, Lagatolla C, Franca R, Bramuzzo M, Stocco G, Decorti G. Emerging Insights on the Interaction Between Anticancer and Immunosuppressant Drugs and Intestinal Microbiota in Pediatric Patients. Clin Transl Sci 2020; 13:238-259. [PMID: 31675176 PMCID: PMC7070880 DOI: 10.1111/cts.12722] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/23/2019] [Indexed: 02/06/2023] Open
Abstract
Diseases affecting the immune system, such as inflammatory bowel disease (IBD), juvenile idiopathic arthritis (JIA), and acute lymphoblastic leukemia (ALL), are pathological conditions affecting the pediatric population and are often associated with alterations in the intestinal microbiota, such as a decrease in bacterial diversity. Growing evidence suggests that gut microbiota can interfere with chemotherapeutic and immunosuppressant drugs, used in the treatment of these diseases, reducing or facilitating drug efficacy. In particular, the effect of intestinal microflora through translocation, immunomodulation, metabolism, enzymatic degradation, and reduction of bacterial diversity seems to be one of the reasons of interindividual variability in the therapeutic response. Although the extent of the role of intestinal microflora in chemotherapy and immunosuppression remains still unresolved, current evidence on bacterial compositional shifts will be taken in consideration together with clinical response to drugs for a better and personalized therapy. This review is focused on the effect of the intestinal microbiota on the efficacy of pharmacological therapy of agents used to treat IBD, JIA, and ALL.
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Affiliation(s)
- Marianna Lucafò
- Institute for Maternal and Child Health – IRCCS “Burlo Garofolo”TriesteItaly
| | - Martina Franzin
- PhD Course in Reproductive and Developmental SciencesUniversity of TriesteTriesteItaly
| | | | - Raffaella Franca
- Department of Medical, Surgical and Health SciencesUniversity of TriesteTriesteItaly
| | - Matteo Bramuzzo
- Institute for Maternal and Child Health – IRCCS “Burlo Garofolo”TriesteItaly
| | - Gabriele Stocco
- Department of Life SciencesUniversity of TriesteTriesteItaly
| | - Giuliana Decorti
- Institute for Maternal and Child Health – IRCCS “Burlo Garofolo”TriesteItaly
- Department of Medical, Surgical and Health SciencesUniversity of TriesteTriesteItaly
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11
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Drug metabolizing enzymes and their inhibitors' role in cancer resistance. Biomed Pharmacother 2018; 105:53-65. [PMID: 29843045 DOI: 10.1016/j.biopha.2018.05.117] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 05/21/2018] [Accepted: 05/23/2018] [Indexed: 12/15/2022] Open
Abstract
Despite continuous research on chemotherapeutic agents, different mechanisms of resistance have become a major pitfall in cancer chemotherapy. Although, exhaustive efforts are being made by several researchers to target resistance against chemotherapeutic agents, there is another class of resistance mechanism which is almost carrying on unattended. This class of resistance includes pharmacokinetics resistance such as efflux by ABC transporters and drug metabolizing enzymes. ABC transporters are the membrane bound proteins which are responsible for the movement of substrates through the cell membrane. Drug metabolizing enzymes are an integral part of phase-II metabolism that helps in the detoxification of exogenous, endogenous and xenobiotics substrates. These include uridine diphospho-glucuronosyltransferases (UGTs), glutathione-S-transferases (GSTs), dihydropyrimidine dehydrogenases (DPDs) and thiopurine methyltransferases (TPMTs). These enzymes may affect the role of drugs in both positive as well negative manner, depending upon the type of tissue and cells present and when present in tumors, can result in drug resistance. However, the underlying mechanism of resistance by drug metabolizing enzymes is still not clear. Here, we have tried to cover various aspects of these enzymes in relation to anticancer drugs.
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12
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Atreya I, Neurath MF. Microbiota: relevant player in thiopurine metabolisation? Gut 2017; 66:1-3. [PMID: 27558925 DOI: 10.1136/gutjnl-2016-312450] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 08/02/2016] [Indexed: 12/08/2022]
Affiliation(s)
- Imke Atreya
- Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Markus F Neurath
- Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
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13
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Schmidt SM, Kuhn H, Micali C, Liller C, Kwaaitaal M, Panstruga R. Interaction of a Blumeria graminis f. sp. hordei effector candidate with a barley ARF-GAP suggests that host vesicle trafficking is a fungal pathogenicity target. MOLECULAR PLANT PATHOLOGY 2014; 15:535-49. [PMID: 24304971 PMCID: PMC6638824 DOI: 10.1111/mpp.12110] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Filamentous phytopathogens, such as fungi and oomycetes, secrete effector proteins to establish successful interactions with their plant hosts. In contrast with oomycetes, little is known about effector functions in true fungi. We used a bioinformatics pipeline to identify Blumeria effector candidates (BECs) from the obligate biotrophic barley powdery mildew pathogen, Blumeria graminis f. sp. hordei (Bgh). BEC1-BEC5 are expressed at different time points during barley infection. BEC1, BEC2 and BEC4 have orthologues in the Arabidopsis thaliana-infecting powdery mildew fungus Golovinomyces orontii. Arabidopsis lines stably expressing the G. orontii BEC2 orthologue, GoEC2, are more susceptible to infection with the non-adapted fungus Erysiphe pisi, suggesting that GoEC2 contributes to powdery mildew virulence. For BEC3 and BEC4, we identified thiopurine methyltransferase, a ubiquitin-conjugating enzyme, and an ADP ribosylation factor-GTPase-activating protein (ARF-GAP) as potential host targets. Arabidopsis knockout lines of the respective HvARF-GAP orthologue (AtAGD5) allowed higher entry levels of E. pisi, but exhibited elevated resistance to the oomycete Hyaloperonospora arabidopsidis. We hypothesize that ARF-GAP proteins are conserved targets of powdery and downy mildew effectors, and we speculate that BEC4 might interfere with defence-associated host vesicle trafficking.
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Affiliation(s)
- Sarah M Schmidt
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829, Köln, Germany
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14
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Milek M, Smid A, Tamm R, Kuzelicki NK, Metspalu A, Mlinaric-Rascan I. Post-translational stabilization of thiopurine S-methyltransferase by S-adenosyl-L-methionine reveals regulation of TPMT*1 and *3C allozymes. Biochem Pharmacol 2012; 83:969-76. [PMID: 22274639 DOI: 10.1016/j.bcp.2012.01.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/07/2012] [Accepted: 01/09/2012] [Indexed: 10/14/2022]
Abstract
Thiopurine S-methyltransferase (TPMT; EC 2.1.1.67) plays a pivotal role in thiopurine treatment outcomes. However, little has been known about its intracellular regulation. Here, we describe the effect of fluctuations in physiological levels of S-adenosyl-L-methionine (SAM) and related metabolites on TPMT activity levels in cell lines and erythrocytes from healthy donors. We determined higher TPMT activity in wild-type TPMT*1/*1 individuals with high SAM concentrations (n=96) compared to the low SAM level group (n=19; P<0.001). These findings confirm the results of our in vitro studies, which demonstrated that the restriction of L-methionine (Met) in cell growth media reversibly decreased TPMT activity and protein levels. Selective inhibition of distinct components of Met metabolism was used to demonstrate that SAM is implicitly responsible for direct post-translational TPMT stabilization. The greatest effect of SAM-mediated TPMT stabilization was observed in the case of wild-type TPMT*1 and variant *3C allozymes. In addition to TPMT genotyping, SAM may serve as an important biochemical marker in individualization of thiopurine therapy.
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Affiliation(s)
- Miha Milek
- Department of Clinical Biochemistry, Faculty of Pharmacy, Askerceva 7, SI-1000, University of Ljubljana, Ljubljana, Slovenia
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15
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Feng Q, Vannaprasaht S, Peng Y, Angsuthum S, Avihingsanon Y, Yee VC, Tassaneeyakul W, Weinshilboum RM. Thiopurine S-methyltransferase pharmacogenetics: functional characterization of a novel rapidly degraded variant allozyme. Biochem Pharmacol 2009; 79:1053-61. [PMID: 19945438 DOI: 10.1016/j.bcp.2009.11.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/13/2009] [Accepted: 11/20/2009] [Indexed: 11/25/2022]
Abstract
A novel human thiopurine S-methyltransferase (TPMT) variant allele, (319 T>G, 107Tyr>Asp, *27), was identified in a Thai renal transplantation recipient with reduced erythrocyte TPMT activity. The TPMT*27 variant allozyme showed a striking decrease in both immunoreactive protein level and enzyme activity after transient expression in a mammalian cell line. We set out to explore the mechanism(s) responsible for decreased expression of this novel variant of an important drug-metabolizing enzyme. We observed accelerated degradation of TPMT*27 protein in a rabbit reticulocyte lysate. TPMT*27 degradation was slowed by proteasome inhibition and involved chaperone proteins-similar to observations with regard to the degradation of the common TPMT*3A variant allozyme. TPMT*27 aggresome formation was also observed in transfected mammalian cells after proteasome inhibition. Inhibition of autophagy also decreased TPMT*27 degradation. Finally, structural analysis and molecular dynamics simulation indicated that TPMT*27 was less stable than was the wild type TPMT allozyme. In summary, TPMT*27 serves to illustrate the potential importance of protein degradation - both proteasome and autophagy-mediated degradation - for the pharmacogenetic effects of nonsynonymous SNPs.
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Affiliation(s)
- Qiping Feng
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic-Mayo Medical School, 200 First Street SW, Rochester, MN 55905, United States
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16
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Lee KH, Saleh L, Anton BP, Madinger CL, Benner JS, Iwig DF, Roberts RJ, Krebs C, Booker SJ. Characterization of RimO, a new member of the methylthiotransferase subclass of the radical SAM superfamily. Biochemistry 2009; 48:10162-74. [PMID: 19736993 DOI: 10.1021/bi900939w] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RimO, encoded by the yliG gene in Escherichia coli, has been recently identified in vivo as the enzyme responsible for the attachment of a methylthio group on the beta-carbon of Asp88 of the small ribosomal protein S12 [Anton, B. P., Saleh, L., Benner, J. S., Raleigh, E. A., Kasif, S., and Roberts, R. J. (2008) Proc. Natl. Acad. Sci. U.S.A. 105, 1826-1831]. To date, it is the only enzyme known to catalyze methylthiolation of a protein substrate; the four other naturally occurring methylthio modifications have been observed on tRNA. All members of the methylthiotransferase (MTTase) family, to which RimO belongs, have been shown to contain the canonical CxxxCxxC motif in their primary structures that is typical of the radical S-adenosylmethionine (SAM) family of proteins. MiaB, the only characterized MTTase, and the enzyme experimentally shown to be responsible for methylthiolation of N(6)-isopentenyladenosine of tRNA in E. coli and Thermotoga maritima, has been demonstrated to harbor two distinct [4Fe-4S] clusters. Herein, we report in vitro biochemical and spectroscopic characterization of RimO. We show by analytical and spectroscopic methods that RimO, overproduced in E. coli in the presence of iron-sulfur cluster biosynthesis proteins from Azotobacter vinelandii, contains one [4Fe-4S](2+) cluster. Reconstitution of this form of RimO (RimO(rcn)) with (57)Fe and sodium sulfide results in a protein that contains two [4Fe-4S](2+) clusters, similar to MiaB. We also show by mass spectrometry that RimO(rcn) catalyzes the attachment of a methylthio group to a peptide substrate analogue that mimics the loop structure bearing aspartyl 88 of the S12 ribosomal protein from E. coli. Kinetic analysis of this reaction shows that the activity of RimO(rcn) in the presence of the substrate analogue does not support a complete turnover. We discuss the possible requirement for an assembled ribosome for fully active RimO in vitro. Our findings are consistent with those of other enzymes that catalyze sulfur insertion, such as biotin synthase, lipoyl synthase, and MiaB.
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Affiliation(s)
- Kyung-Hoon Lee
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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17
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Peng Y, Feng Q, Wilk D, Adjei AA, Salavaggione OE, Weinshilboum RM, Yee VC. Structural basis of substrate recognition in thiopurine s-methyltransferase. Biochemistry 2008; 47:6216-25. [PMID: 18484748 DOI: 10.1021/bi800102x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thiopurine S-methyltransferase (TPMT) modulates the cytotoxic effects of thiopurine prodrugs such as 6-mercaptopurine by methylating them in a reaction using S-adenosyl- l-methionine as the donor. Patients with TPMT variant allozymes exhibit diminished levels of protein and/or enzyme activity and are at risk for thiopurine drug-induced toxicity. We have determined two crystal structures of murine TPMT, as a binary complex with the product S-adenosyl- l-homocysteine and as a ternary complex with S-adenosyl- l-homocysteine and the substrate 6-mercaptopurine, to 1.8 and 2.0 A resolution, respectively. Comparison of the structures reveals that an active site loop becomes ordered upon 6-mercaptopurine binding. The positions of the two ligands are consistent with the expected S N2 reaction mechanism. Arg147 and Arg221, the only polar amino acids near 6-mercaptopurine, are highlighted as possible participants in substrate deprotonation. To probe whether these residues are important for catalysis, point mutants were prepared in the human enzyme. Substitution of Arg152 (Arg147 in murine TPMT) with glutamic acid decreases V max and increases K m for 6-mercaptopurine but not K m for S-adenosyl- l-methionine. Substitution at this position with alanine or histidine and similar substitutions of Arg226 (Arg221 in murine TPMT) result in no effect on enzyme activity. The double mutant Arg152Ala/Arg226Ala exhibits a decreased V max and increased K m for 6-mercaptopurine. These observations suggest that either Arg152 or Arg226 may participate in some fashion in the TPMT reaction, with one residue compensating when the other is altered, and that Arg152 may interact with substrate more directly than Arg226, consistent with observations in the murine TPMT crystal structure.
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Affiliation(s)
- Yi Peng
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA
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18
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RimO, a MiaB-like enzyme, methylthiolates the universally conserved Asp88 residue of ribosomal protein S12 in Escherichia coli. Proc Natl Acad Sci U S A 2008; 105:1826-31. [PMID: 18252828 DOI: 10.1073/pnas.0708608105] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ribosomal protein S12 undergoes a unique posttranslational modification, methylthiolation of residue D88, in Escherichia coli and several other bacteria. Using mass spectrometry, we have identified the enzyme responsible for this modification in E. coli, the yliG gene product. This enzyme, which we propose be called RimO, is a radical-S-adenosylmethionine protein that bears strong sequence similarity to MiaB, which methylthiolates tRNA. We show that RimO and MiaB represent two of four subgroups of a larger, ancient family of likely methylthiotransferases, the other two of which are typified by Bacillus subtilis YqeV and Methanococcus jannaschii Mj0867, and we predict that RimO is unique among these subgroups in its modification of protein as opposed to tRNA. Despite this, RimO has not significantly diverged from the other three subgroups at the sequence level even within the C-terminal TRAM domain, which in the methyltransferase RumA is known to bind the RNA substrate and which we presume to be responsible for substrate binding and recognition in all four subgroups of methylthiotransferases. To our knowledge, RimO and MiaB represent the most extreme known case of resemblance between enzymes modifying protein and nucleic acid. The initial results presented here constitute a bioinformatics-driven prediction with preliminary experimental validation that should serve as the starting point for several interesting lines of further inquiry.
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19
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Hartford C, Vasquez E, Schwab M, Edick MJ, Rehg JE, Grosveld G, Pui CH, Evans WE, Relling MV. Differential Effects of Targeted Disruption of Thiopurine Methyltransferase on Mercaptopurine and Thioguanine Pharmacodynamics. Cancer Res 2007; 67:4965-72. [PMID: 17510427 DOI: 10.1158/0008-5472.can-06-3508] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The recessive deficiency in thiopurine methyltransferase (TPMT), caused by germ-line polymorphisms in TPMT, can cause severe toxicity after mercaptopurine. However, the significance of heterozygosity and the effect of the polymorphism on thioguanine or in the absence of thiopurines is not known. To address these issues, we created a murine knockout of Tpmt. Pharmacokinetic and pharmacodynamic studies of mercaptopurine and thioguanine were done in Tpmt(-/-), Tpmt(+/-), and Tpmt(+/+) mice and variables were compared among genotypes. Methylated thiopurine and thioguanine nucleotide metabolites differed among genotypes after treatment with mercaptopurine (P < 0.0001 and P = 0.044, respectively) and thioguanine (P = 0.011 and P = 0.002, respectively). Differences in toxicity among genotypes were more pronounced following treatment with 10 daily doses of mercaptopurine at 100 mg/kg/d (0%, 68%, and 100% 50-day survival; P = 0.0003) than with thioguanine at 5 mg/kg/d (0%, 33%, and 50% 15-day survival; P = 0.07) in the Tpmt(-/-), Tpmt(+/-), and Tpmt(+/+) genotypes, respectively. Myelosuppression and weight loss exhibited a haploinsufficient phenotype after mercaptopurine, whereas haploinsufficiency was less prominent with thioguanine. In the absence of drug challenge, there was no apparent phenotype. The murine model recapitulates many clinical features of the human polymorphism; indicates that mercaptopurine is more affected by the TPMT polymorphism than thioguanine; and provides a preclinical system for establishing safer regimens of genetically influenced antileukemic drug therapy.
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Affiliation(s)
- Christine Hartford
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, University of Tennessee, Memphis, Tennessee, USA
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20
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Wu H, Horton JR, Battaile K, Allali-Hassani A, Martin F, Zeng H, Loppnau P, Vedadi M, Bochkarev A, Plotnikov AN, Cheng X. Structural basis of allele variation of human thiopurine-S-methyltransferase. Proteins 2007; 67:198-208. [PMID: 17243178 PMCID: PMC2750861 DOI: 10.1002/prot.21272] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Human thiopurine S-methyltransferase (TPMT) exhibits considerable person-to-person variation in activity to thiopurine drugs. We have produced an N-terminal truncation of human TPMT protein, crystallized the protein in complex with the methyl donor product S-adenosyl-L-homocysteine, and determined the atomic structure to the resolution of 1.58 and 1.89 A, respectively, for the seleno-methionine incorporated and wild type proteins. The structure of TPMT indicates that the naturally occurring amino acid polymorphisms scatter throughout the structure, and that the amino acids whose alteration have the most influence on function are those that form intra-molecular stabilizing interactions (mainly van der Waals contacts). Furthermore, we have produced four TPMT mutant proteins containing variant alleles of TPMT*2, *3A, *3B, and *3C and examined the structure-function relationship of the mutant proteins based on their expression and solubility in bacteria and their thermostability profile.
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Affiliation(s)
- Hong Wu
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
| | - John R. Horton
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Kevin Battaile
- IMCA-CAT, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439
| | | | - Fernando Martin
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
| | - Hong Zeng
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
| | - Peter Loppnau
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
| | - Masoud Vedadi
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
| | - Alexey Bochkarev
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Alexander N. Plotnikov
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Correspondence to: Xiaodong Cheng, Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322. E-mail: or Alexander N. Plotnikov, Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
- Correspondence to: Xiaodong Cheng, Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322. E-mail: or Alexander N. Plotnikov, Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L5, Canada
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21
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Milek M, Murn J, Jaksic Z, Lukac Bajalo J, Jazbec J, Mlinaric Rascan I. Thiopurine S-Methyltransferase Pharmacogenetics: Genotype to Phenotype Correlation in the Slovenian Population. Pharmacology 2006; 77:105-14. [PMID: 16691038 DOI: 10.1159/000093278] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Accepted: 03/20/2006] [Indexed: 11/19/2022]
Abstract
The toxicity of thiopurine drugs has been correlated to the activity of thiopurine S-methyltransferase (TPMT), whose interindividual variation is a consequence of genetic polymorphisms. We have herein investigated the relevance of some genetic markers for the prediction of thiopurine-related toxicities and to determine the genotype to phenotype correlation in the Slovenian population. The most prevalent mutant allele in the Slovenian population is TPMT*3A (4.1%), followed by TPMT*3C (0.5) and TPMT*3B (0.3), while the TPMT*2 allele was not found in any of the examined samples. TPMT enzyme activity distribution in the subgroup sample was bimodal and as such correlated with genetic data. Using a cutoff value of 9.82 pmol/10(7) RBC per h, the genetic data correctly predicted TPMT enzyme activity in 91.6% of the examined individuals. Pharmacogenetic TPMT analyses have therefore proved to have significant clinical implications for prediction of individuals' responses to treatment with thiopurine drugs in order to avoid possible life-threatening therapy-related toxicities.
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Affiliation(s)
- M Milek
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
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22
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Salavaggione OE, Wang L, Wiepert M, Yee VC, Weinshilboum RM. Thiopurine S-methyltransferase pharmacogenetics: variant allele functional and comparative genomics. Pharmacogenet Genomics 2006; 15:801-15. [PMID: 16220112 DOI: 10.1097/01.fpc.0000174788.69991.6b] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Thiopurine S-methyltransferase (TPMT) catalyses the S-methylation of thiopurine drugs. Genetic polymorphisms for TPMT are a major factor responsible for large individual variations in thiopurine toxicity and therapeutic effect. The present study investigated the functional effects of human TPMT variant alleles that alter the encoded amino acid sequence of the enzyme, TPMT*2, *3A, *3B, *3C and *5 to *13. After expression in COS-1 cells and correction for transfection efficiency, allozymes encoded by these alleles displayed levels of activity that varied from virtually undetectable (*3A,*3B and *5) to 98% (*7) of that observed for the wild-type allele. Although some allozymes had significant elevations in apparent Km values for 6-mercaptopurine and S-adenosyl-L-methionine (i.e. the two cosubstrates for the reaction), the level of enzyme protein was the major factor responsible for variation in activity. Quantitative Western blot analysis demonstrated that the level of enzyme protein correlated closely with level of activity for all allozymes except TPMT*5. Furthermore, protein levels correlated with rates of TPMT degradation. TPMT amino acid sequences were then determined for 16 non-human mammalian species and those sequences (plus seven reported previously, including two nonmammalian vertebrate species) were used to determine amino acid sequence conservation. Most human TPMT variant allozymes had alterations of residues that were highly conserved during vertebrate evolution. Finally, a human TPMT homology structural model was created on the basis of a Pseudomonas structure (the only TPMT structure solved to this time), and the model was used to infer the functional consequences of variant allozyme amino acid sequence alterations. These studies indicate that a common mechanism responsible for alterations in the activity of variant TPMT allozymes involves alteration in the level of enzyme protein due, at least in part, to accelerated degradation.
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Affiliation(s)
- Oreste E Salavaggione
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine-Mayo Clinic, Rochester, Minnesota 55905, USA
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23
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Sasaki T, Goto E, Konno Y, Hiratsuka M, Mizugaki M. Three Novel Single Nucleotide Polymorphisms of the Human Thiopurine S-Methyltransferase Gene in Japanese Individuals. Drug Metab Pharmacokinet 2006; 21:332-6. [PMID: 16946561 DOI: 10.2133/dmpk.21.332] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, the entire coding sequence and the exon-intron junctions of the thiopurine S-methyltransferase (TPMT) gene from 200 Japanese individuals were screened for mutation. Three novel single nucleotide polymorphisms (SNPs) were identified-106G>A in exon 3 (Gly36Ser, *20 allele), 967A>G in 3'-untranslated region, and -87C>T in intron 8. The allele frequencies were 0.003 for 106G>A, 0.003 for 967A>G, and 0.010 for IVS8 -87C>T. In addition, the three known SNPs, 474T>C (Ile158Ile), 719A>G (Tyr240Cys, *3C allele), and IVS4 +35C>T were detected at frequencies of 0.299, 0.010, and 0.421, respectively.
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Affiliation(s)
- Takamitsu Sasaki
- Department of Clinical Pharmaceutics, Tohoku Pharmaceutical University, Sendai, Japan
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24
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Favre-Bonté S, Ranjard L, Colinon C, Prigent-Combaret C, Nazaret S, Cournoyer B. Freshwater selenium-methylating bacterial thiopurine methyltransferases: diversity and molecular phylogeny. Environ Microbiol 2005; 7:153-64. [PMID: 15658983 DOI: 10.1111/j.1462-2920.2004.00670.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The diversity of bacterial thiopurine methyltransferases (bTPMT) among five natural Se-methylating freshwaters was investigated by polymerase chain reaction (PCR) screenings and sequencings. DNA sequence analyses confirmed the cloned products' identity and revealed a broad diversity of freshwater TPMTs. Neighbour-joining (NJ) phylogenetic analyses combining these sequences, all GenBank entries closely related to these sequences and deduced TPMTs obtained in this work from selected gamma-proteobacteria showed TPMTs to form a distinct radiation, closely related to UbiG methyltransferases. Inside the TPMT phylogenetic cluster, eukaryote sequences diverged early from the bacterial ones, and all the bacterial database entries belonged to a subgroup of gamma-proteobacteria, with an apparent lateral transfer of a particular allele to beta-proteobacteria of Bordetella. The NJ phylogenetic tree revealed 22 bTPMT lineages, 10 of which harboured freshwater sequences. All lineages showed deep and long branches indicative of major genetic drifts outside regions encoding highly conserved domains. Selected residues among these highly variable domains could reflect adaptations for particular ecological niches. PCR lineage-specific primers differentiated Se-methylating freshwaters according to their 'tpm lineage' signatures. Most freshwater tpm alleles were found to be distinct from those available in the databases, but a group of tpm was found encoding TPMTs identical to an Aeromonas veronii TPMT characterized in this work.
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Affiliation(s)
- S Favre-Bonté
- UMR CNRS UCBL 5557 Ecologie Microbienne (Center for Microbial Ecology), Research Group on Opportunistic Pathogens and Environment, Université Claude Bernard - Lyon 1, Mendel Bldg, 5th floor, 69622 Villeurbanne Cedex, France
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25
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Wang L, Nguyen TV, McLaughlin RW, Sikkink LA, Ramirez-Alvarado M, Weinshilboum RM. Human thiopurine S-methyltransferase pharmacogenetics: variant allozyme misfolding and aggresome formation. Proc Natl Acad Sci U S A 2005; 102:9394-9. [PMID: 15967990 PMCID: PMC1153717 DOI: 10.1073/pnas.0502352102] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Indexed: 11/18/2022] Open
Abstract
Thiopurine S-methyltransferase (TPMT) catalyzes the S-methylation of thiopurine drugs. TPMT genetic polymorphisms represent a striking example of the potential clinical value of pharmacogenetics. Subjects homozygous for TPMT*3A, the most common variant allele for low activity, an allele that encodes a protein with two changes in amino acid sequence, are at greatly increased risk for life-threatening toxicity when treated with standard doses of thiopurines. These subjects have virtually undetectable levels of TPMT protein. In this study, we tested the hypothesis that TPMT*3A might result in protein misfolding and aggregation. We observed that TPMT*3A forms aggresomes in cultured cells and that it aggregates in vitro, functional mechanisms not previously described in pharmacogenetics. Furthermore, there was a correlation among TPMT half-life values in rabbit reticulocyte lysate, aggresome formation in COS-1 cells, and protein aggregation in vitro for the three variant allozymes encoded by alleles that include the two TPMT*3A single-nucleotide polymorphisms. These observations were compatible with a common structural explanation for all of these effects, a conclusion supported by size-exclusion chromatography and CD spectroscopy. The results of these experiments provide insight into a unique pharmacogenetic mechanism by which common polymorphisms affect TPMT protein function and, as a result, therapeutic response to thiopurine drugs.
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Affiliation(s)
- Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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26
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Scheuermann TH, Keeler C, Hodsdon ME. Consequences of Binding an S-Adenosylmethionine Analogue on the Structure and Dynamics of the Thiopurine Methyltransferase Protein Backbone. Biochemistry 2004; 43:12198-209. [PMID: 15379558 DOI: 10.1021/bi0492556] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In humans, the enzyme thiopurine methyltransferase (TPMT) metabolizes 6-thiopurine (6-TP) medications, commonly used for immune suppression and for the treatment of hematopoietic malignancies. Genetic polymorphisms in the TPMT protein sequence accelerate intracellular degradation of the enzyme through an ubiquitylation and proteasomal-dependent pathway. Research has led to the hypothesis that these polymorphisms destabilize the native structure of TPMT, resulting in the formation of misfolded or partially unfolded states, which are subsequently recognized for intracellular degradation. Addition of the cosubstrate, S-adenosylmethionine (SAM), prevents degradation of the TPMT polymorphs in experimental assays, presumably by stabilizing the native structure. Using a bacterial orthologue of TPMT from Pseudomonas syringae, we have used NMR spectroscopy to describe the consequences of binding sinefungin, a SAM analogue, on the structure and dynamics of the TPMT protein backbone. NMR chemical shift mapping experiments localize sinefungin to a highly conserved site in classical methyltransferases. Distal chemical shift changes involving the presumed active site cover imply indirect conformational changes induced by sinefungin, which may play a role in substrate recognition or the catalytic mechanism. Analysis of protein backbone dynamics based on NMR relaxation reveals a combination of complementary effects. Whereas the peripheral, inserted structural elements of the TPMT topology are conformationally stabilized by the presence of sinefungin, a consistent increase in backbone mobility is observed for the central, conserved structural elements. The potential implications for the structural and dynamic effects of binding sinefungin for the catalytic mechanism of the enzyme and the stabilization of the degradation-susceptible TPMT polymorphs are discussed.
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Affiliation(s)
- Thomas H Scheuermann
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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