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Dumazer A, Gómez-Santacana X, Malhaire F, Jopling C, Maurel D, Lebon G, Llebaria A, Goudet C. Optical Control of Adenosine A 2A Receptor Using Istradefylline Photosensitivity. ACS Chem Neurosci 2024; 15:645-655. [PMID: 38275568 DOI: 10.1021/acschemneuro.3c00721] [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] [Indexed: 01/27/2024] Open
Abstract
In recent years, there has been growing interest in the potential therapeutic use of inhibitors of adenosine A2A receptors (A2AR) for the treatment of neurodegenerative diseases and cancer. Nevertheless, the widespread expression of A2AR throughout the body emphasizes the importance of temporally and spatially selective ligands. Photopharmacology is an emerging strategy that utilizes photosensitive ligands to attain high spatiotemporal precision and regulate the function of biomolecules using light. In this study, we combined photochemistry and cellular and in vivo photopharmacology to investigate the light sensitivity of the FDA-approved antagonist istradefylline and its potential use as an A2AR photopharmacological tool. Our findings reveal that istradefylline exhibits rapid trans-to-cis isomerization under near-UV light, and prolonged exposure results in the formation of photocycloaddition products. We demonstrate that exposure to UV light triggers a time-dependent decrease in the antagonistic activity of istradefylline in A2AR-expressing cells and enables real-time optical control of A2AR signaling in living cells and zebrafish. Together, these data demonstrate that istradefylline is a photoinactivatable A2AR antagonist and that this property can be utilized to perform photopharmacological experiments in living cells and animals.
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Affiliation(s)
- Anaëlle Dumazer
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain
| | - Xavier Gómez-Santacana
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain
| | - Fanny Malhaire
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Chris Jopling
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Damien Maurel
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Guillaume Lebon
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Amadeu Llebaria
- MCS, Laboratory of Medicinal Chemistry and Synthesis, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain
| | - Cyril Goudet
- IGF, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
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2
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IJzerman AP, Jacobson KA, Müller CE, Cronstein BN, Cunha RA. International Union of Basic and Clinical Pharmacology. CXII: Adenosine Receptors: A Further Update. Pharmacol Rev 2022; 74:340-372. [PMID: 35302044 PMCID: PMC8973513 DOI: 10.1124/pharmrev.121.000445] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Our previous International Union of Basic and Clinical Pharmacology report on the nomenclature and classification of adenosine receptors (2011) contained a number of emerging developments with respect to this G protein-coupled receptor subfamily, including protein structure, protein oligomerization, protein diversity, and allosteric modulation by small molecules. Since then, a wealth of new data and results has been added, allowing us to explore novel concepts such as target binding kinetics and biased signaling of adenosine receptors, to examine a multitude of receptor structures and novel ligands, to gauge new pharmacology, and to evaluate clinical trials with adenosine receptor ligands. This review should therefore be considered a further update of our previous reports from 2001 and 2011. SIGNIFICANCE STATEMENT: Adenosine receptors (ARs) are of continuing interest for future treatment of chronic and acute disease conditions, including inflammatory diseases, neurodegenerative afflictions, and cancer. The design of AR agonists ("biased" or not) and antagonists is largely structure based now, thanks to the tremendous progress in AR structural biology. The A2A- and A2BAR appear to modulate the immune response in tumor biology. Many clinical trials for this indication are ongoing, whereas an A2AAR antagonist (istradefylline) has been approved as an anti-Parkinson agent.
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Affiliation(s)
- Adriaan P IJzerman
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands (A.P.IJ.); National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Molecular Recognition Section, Bethesda, Maryland (K.A.J.); Universität Bonn, Bonn, Germany (C.E.M.); New York University School of Medicine, New York, New York (B.N.C.); and Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal (R.A.C.)
| | - Kenneth A Jacobson
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands (A.P.IJ.); National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Molecular Recognition Section, Bethesda, Maryland (K.A.J.); Universität Bonn, Bonn, Germany (C.E.M.); New York University School of Medicine, New York, New York (B.N.C.); and Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal (R.A.C.)
| | - Christa E Müller
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands (A.P.IJ.); National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Molecular Recognition Section, Bethesda, Maryland (K.A.J.); Universität Bonn, Bonn, Germany (C.E.M.); New York University School of Medicine, New York, New York (B.N.C.); and Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal (R.A.C.)
| | - Bruce N Cronstein
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands (A.P.IJ.); National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Molecular Recognition Section, Bethesda, Maryland (K.A.J.); Universität Bonn, Bonn, Germany (C.E.M.); New York University School of Medicine, New York, New York (B.N.C.); and Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal (R.A.C.)
| | - Rodrigo A Cunha
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands (A.P.IJ.); National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Molecular Recognition Section, Bethesda, Maryland (K.A.J.); Universität Bonn, Bonn, Germany (C.E.M.); New York University School of Medicine, New York, New York (B.N.C.); and Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal (R.A.C.)
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3
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Wang S, Zhao Y, Zhang Z, Zhang Y, Li L. Recent advances in amino acid-metal coordinated nanomaterials for biomedical applications. Chin J Chem Eng 2021. [DOI: 10.1016/j.cjche.2021.03.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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4
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Janse van Rensburg HD, Legoabe LJ, Terre'Blanche G, Aucamp J. Synthesis and evaluation of methoxy substituted 2-benzoyl-1-benzofuran derivatives as lead compounds for the development adenosine A1 and/or A2A receptor antagonists. Bioorg Chem 2020; 94:103459. [DOI: 10.1016/j.bioorg.2019.103459] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 11/16/2019] [Accepted: 11/19/2019] [Indexed: 12/27/2022]
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5
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Lui BF, Tierce NT, Tong F, Sroda MM, Lu H, Read de Alaniz J, Bardeen CJ. Unusual concentration dependence of the photoisomerization reaction in donor–acceptor Stenhouse adducts. Photochem Photobiol Sci 2019; 18:1587-1595. [DOI: 10.1039/c9pp00130a] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The isomerization rates of a photochromic donor–acceptor Stenhouse adduct depend on concentration. The net photoisomerization rate decreases with increasing concentration in liquids and polymers.
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Affiliation(s)
- Brandon F. Lui
- Department of Chemistry
- University of California
- Riverside
- USA
| | | | - Fei Tong
- Department of Chemistry
- University of California
- Riverside
- USA
| | - Miranda M. Sroda
- Department of Chemistry and Biochemistry
- University of California Santa Barbara
- Santa Barbara
- USA
| | - Hao Lu
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 400044
- P.R. China
| | - Javier Read de Alaniz
- Department of Chemistry and Biochemistry
- University of California Santa Barbara
- Santa Barbara
- USA
| | - Christopher J. Bardeen
- Department of Chemistry
- University of California
- Riverside
- USA
- Materials Science and Engineering Program
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6
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Preti D, Baraldi PG, Moorman AR, Borea PA, Varani K. History and perspectives of A2A adenosine receptor antagonists as potential therapeutic agents. Med Res Rev 2015; 35:790-848. [PMID: 25821194 DOI: 10.1002/med.21344] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Growing evidence emphasizes that the purine nucleoside adenosine plays an active role as a local regulator in different pathologies. Adenosine is a ubiquitous nucleoside involved in various physiological and pathological functions by stimulating A1 , A2A , A2B , and A3 adenosine receptors (ARs). At the present time, the role of A2A ARs is well known in physiological conditions and in a variety of pathologies, including inflammatory tissue damage and neurodegenerative disorders. In particular, the use of selective A2A antagonists has been reported to be potentially useful in the treatment of Parkinson's disease (PD). In this review, A2A AR signal transduction pathways, together with an analysis of the structure-activity relationships of A2A antagonists, and their corresponding pharmacological roles and therapeutic potential have been presented. The initial results from an emerging polypharmacological approach are also analyzed. This approach is based on the optimization of the affinity and/or functional activity of the examined compounds toward multiple targets, such as A1 /A2A ARs and monoamine oxidase-B (MAO-B), both closely implicated in the pathogenesis of PD.
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Affiliation(s)
- Delia Preti
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Pier Giovanni Baraldi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | | | - Pier Andrea Borea
- Section of Pharmacology, Department of Medical Science, University of Ferrara, 44121, Ferrara, Italy
| | - Katia Varani
- Section of Pharmacology, Department of Medical Science, University of Ferrara, 44121, Ferrara, Italy
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7
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Mishina M, Ishiwata K. Adenosine Receptor PET Imaging in Human Brain. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 119:51-69. [DOI: 10.1016/b978-0-12-801022-8.00002-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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8
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de Lera Ruiz M, Lim YH, Zheng J. Adenosine A2A Receptor as a Drug Discovery Target. J Med Chem 2013; 57:3623-50. [DOI: 10.1021/jm4011669] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Manuel de Lera Ruiz
- Department
of Chemical Research, Merck Research Laboratories, 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Yeon-Hee Lim
- Department
of Chemical Research, Merck Research Laboratories, 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Junying Zheng
- Department
of Chemical Research, Merck Research Laboratories, 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
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9
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Koch P, Akkari R, Brunschweiger A, Borrmann T, Schlenk M, Küppers P, Köse M, Radjainia H, Hockemeyer J, Drabczyńska A, Kieć-Kononowicz K, Müller CE. 1,3-Dialkyl-substituted tetrahydropyrimido[1,2-f]purine-2,4-diones as multiple target drugs for the potential treatment of neurodegenerative diseases. Bioorg Med Chem 2013; 21:7435-52. [PMID: 24139167 DOI: 10.1016/j.bmc.2013.09.044] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/14/2013] [Accepted: 09/17/2013] [Indexed: 11/29/2022]
Abstract
Adenosine receptors and monoamine oxidases are drug targets for neurodegenerative diseases such as Parkinson's and Alzheimer's disease. In the present study we prepared a library of 55 mostly novel tetrahydropyrimido[2,1-f]purinediones with various substituents in the 1- and 3-position (1,3-dimethyl, 1,3-diethyl, 1,3-dipropyl, 1-methyl-3-propargyl) and broad variation in the 9-position. A synthetic strategy to obtain 3-propargyl-substituted tetrahydropyrimido[2,1-f]purinedione derivatives was developed. The new compounds were evaluated for their interaction with all four adenosine receptor subtypes and for their ability to inhibit monoamine oxidases (MAO). Introduction of mono- or di-chloro-substituted phenyl, benzyl or phenethyl residues at N9 of the 1,3-dimethyl series led to the discovery of a novel class of potent MAO-B inhibitors, the most potent compound being 9-(3,4-dichlorobenzyl)-1,3-dimethyl-6,7,8,9-tetrahydropyrimido[1,2-f]purine-2,4(1H,3H)-dione (21g, IC(50) human MAO-B: 0.0629 μM), which displayed high selectivity versus the other investigated targets. Potent dually active A1/A2A adenosine receptor antagonists were identified, for example, 9-benzyl-1-methyl-3-propargyl-6,7,8,9-tetrahydropyrimido[1,2-f]purine-2,4(1H,3H)dione (19f, Ki, human receptors, A1: 0.249 μM, A2A: 0.253 μM). Several compounds showed triple-target inhibition, the best compound being 9-(2-methoxybenzyl)-1-methyl-3-(prop-2-ynyl)-6,7,8,9-tetrahydro pyrimido [1,2-f]purine-2,4(1H,3H)-dione (19g, Ki A1: 0.605 μM, Ki A2A: 0.417 μM, IC(50) MAO-B: 1.80 μM). Compounds inhibiting several different targets involved in neurodegeneration may exhibit additive or even synergistic effects in vivo.
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Affiliation(s)
- Pierre Koch
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
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10
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Stössel A, Schlenk M, Hinz S, Küppers P, Heer J, Gütschow M, Müller CE. Dual targeting of adenosine A(2A) receptors and monoamine oxidase B by 4H-3,1-benzothiazin-4-ones. J Med Chem 2013; 56:4580-96. [PMID: 23631427 DOI: 10.1021/jm400336x] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Blockade of A2A adenosine receptors (A2AARs) and inhibition of monoamine oxidase B (MAO-B) in the brain are considered attractive strategies for the treatment of neurodegenerative diseases such as Parkinson's disease (PD). In the present study, benzothiazinones, e.g., 2-(3-chlorophenoxy)-N-(4-oxo-4H-3,1-benzothiazin-2-yl)acetamide (13), were identified as a novel class of potent MAO-B inhibitors (IC50 human MAO-B: 1.63 nM). Benzothiazinones with large substituents in the 2-position, e.g., methoxycinnamoylamino, phenylbutyrylamino, or chlorobenzylpiperazinylbenzamido residues (14, 17, 27, and 28), showed high affinity and selectivity for A2AARs (Ki human A2AAR: 39.5-69.5 nM). By optimizing benzothiazinones for both targets, the first potent, dual-acting A2AAR/MAO-B inhibitors with a nonxanthine structure were developed. The best derivative was N-(4-oxo-4H-3,1-benzothiazin-2-yl)-4-phenylbutanamide (17, Ki human A2A, 39.5 nM; IC50 human MAO-B, 34.9 nM; selective versus other AR subtypes and MAO-A), which inhibited A2AAR-induced cAMP accumulation and showed competitive, reversible MAO-B inhibition. The new compounds may be useful tools for validating the A2AAR/MAO-B dual target approach in PD.
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Affiliation(s)
- Anne Stössel
- PharmaCenter Bonn, University of Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, Bonn, Germany
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11
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Rivara S, Piersanti G, Bartoccini F, Diamantini G, Pala D, Riccioni T, Stasi MA, Cabri W, Borsini F, Mor M, Tarzia G, Minetti P. Synthesis of (E)-8-(3-Chlorostyryl)caffeine Analogues Leading to 9-Deazaxanthine Derivatives as Dual A2A Antagonists/MAO-B Inhibitors. J Med Chem 2013; 56:1247-61. [DOI: 10.1021/jm301686s] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Silvia Rivara
- Dipartimento
di Farmacia, Università
degli Studi di Parma, Viale G.P. Usberti 27 A, I-43124 Parma, Italy
| | - Giovanni Piersanti
- Department of Biomolecular Sciences,
University of Urbino, Piazza Rinascimento 6, I-61029 Urbino (PU),
Italy
| | - Francesca Bartoccini
- Department of Biomolecular Sciences,
University of Urbino, Piazza Rinascimento 6, I-61029 Urbino (PU),
Italy
| | - Giuseppe Diamantini
- Department of Biomolecular Sciences,
University of Urbino, Piazza Rinascimento 6, I-61029 Urbino (PU),
Italy
| | - Daniele Pala
- Dipartimento
di Farmacia, Università
degli Studi di Parma, Viale G.P. Usberti 27 A, I-43124 Parma, Italy
| | - Teresa Riccioni
- Sigma-Tau Industrie Farmaceutiche
Riunite
S.p.A., Via Pontina Km 30,400, I-00040 Pomezia, Italy
| | - Maria Antonietta Stasi
- Sigma-Tau Industrie Farmaceutiche
Riunite
S.p.A., Via Pontina Km 30,400, I-00040 Pomezia, Italy
| | - Walter Cabri
- Sigma-Tau Industrie Farmaceutiche
Riunite
S.p.A., Via Pontina Km 30,400, I-00040 Pomezia, Italy
| | - Franco Borsini
- Sigma-Tau Industrie Farmaceutiche
Riunite
S.p.A., Via Pontina Km 30,400, I-00040 Pomezia, Italy
| | - Marco Mor
- Dipartimento
di Farmacia, Università
degli Studi di Parma, Viale G.P. Usberti 27 A, I-43124 Parma, Italy
| | - Giorgio Tarzia
- Department of Biomolecular Sciences,
University of Urbino, Piazza Rinascimento 6, I-61029 Urbino (PU),
Italy
| | - Patrizia Minetti
- Sigma-Tau Industrie Farmaceutiche
Riunite
S.p.A., Via Pontina Km 30,400, I-00040 Pomezia, Italy
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12
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Huang Y, Song F, Wang Z, Xi P, Wu N, Wang Z, Lan J, You J. Dehydrogenative Heck coupling of biologically relevant N-heteroarenes with alkenes: discovery of fluorescent core frameworks. Chem Commun (Camb) 2012; 48:2864-6. [DOI: 10.1039/c2cc17557f] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Abstract
The natural plant alkaloids caffeine and theophylline were the first adenosine receptor (AR) antagonists described in the literature. They exhibit micromolar affinities and are non-selective. A large number of derivatives and analogues were subsequently synthesized and evaluated as AR antagonists. Very potent antagonists have thus been developed with selectivity for each of the four AR subtypes.
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Affiliation(s)
- Christa Müller
- PharmaCenter Bonn, Pharmaceutical Sciences Bonn (PSB), University of Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, An der Immenburg 4, D-53121 Bonn, Germany, Phone +49-228-73-2301, Fax +49-228-73-2567
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bldg. 8A, Rm. B1A-19, NIH, NIDDK, LBC, Bethesda, MD 20892, United States of America, Phone +1-301-496-9024, Fax +1-301-480-8422
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14
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Sihver W, Schulze A, Wutz W, Stüsgen S, Olsson RA, Bier D, Holschbach MH. Autoradiographic comparison of in vitro binding characteristics of various tritiated adenosine A2A receptor ligands in rat, mouse and pig brain and first ex vivo results. Eur J Pharmacol 2009; 616:107-14. [PMID: 19545560 DOI: 10.1016/j.ejphar.2009.06.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/29/2009] [Accepted: 06/09/2009] [Indexed: 02/08/2023]
Abstract
The adenosine A(2A) receptor in the basal ganglia is involved in the control of movement and plays a role in movement disorders such as Parkinsonism. Developing ligands to evaluate that receptor by noninvasive methods such as positron emission tomography has a high priority. In vitro radioligand binding guides the selection of ligands for in vivo application. This study measured the binding of the adenosine A(2A) receptor antagonist [(3)H]MSX-2 (3-(3-hydroxypropyl)-8-m-methoxystyryl)-7-methyl-1-propargylxanthine) to rat, mouse and pig brain by autoradiography. Other studies measured binding to membranes from PC12 pheochromocytoma cells. Those binding parameters were compared to those of the adenosine A(2A) receptor antagonist [(3)H]ZM241385 (4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino)ethyl)phenol), the adenosine A(2A) receptor agonist [(3)H]CGS21680 (2-[p-(2-carboxyethyl)-phenethylamino]-5'-N-ethylcarboxamidoadenosine) and the unselective adenosine receptor agonist [(3)H]NECA (5'N-ethylcarboxamido)adenosine). The potency order (K(d)) in the three species was [(3)H]ZM241385<[(3)H]MSX-2<[(3)H]NECA<[(3)H]CGS21680. The density of [(3)H]MSX-2 binding sites was greater in the striatum than in the cortex. Preliminary ex vivo experiments showed that by 10min after iv injection, [(3)H]MSX-2 and [(3)H]CGS21680 crossed the blood-brain barrier to the extent of almost 1% ID/g brain tissue, but [(3)H]NECA and [(3)H]ZM241385 to only 0.2% ID/g. The prior administration of unlabeled ZM241385 significantly lowered brain uptake of [(3)H]MSX-2. In conclusion, [(3)H]MSX-2 has a high affinity and sufficient selectivity for the adenosine A(2A) receptor. It penetrates the blood-brain barrier. Sensitivity to photoisomerization is a limitation. Further investigations assess its suitability as a ligand for imaging the brain adenosine A(2A) receptor.
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Affiliation(s)
- Wiebke Sihver
- Institute of Neuroscience and Medicine, INM-5, (Nuclear Chemistry), Research Center Jülich, 52425 Jülich, Germany.
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15
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Abstract
Advances in radiotracer chemistry have resulted in the development of novel molecular imaging probes for adenosine receptors (ARs). With the availability of these molecules, the function of ARs in human pathophysiology as well as the safety and efficacy of approaches to the different AR targets can now be determined. Molecular imaging is a rapidly growing field of research that allows the identification of molecular targets and functional processes in vivo. It is therefore gaining increasing interest as a tool in drug development because it permits the process of evaluating promising therapeutic targets to be stratified. Further, molecular imaging has the potential to evolve into a useful diagnostic tool, particularly for neurological and psychiatric disorders. This chapter focuses on currently available AR ligands that are suitable for molecular neuroimaging and describes first applications in healthy subjects and patients using positron emission tomography (PET).
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Affiliation(s)
- Andreas Bauer
- Institute of Neuroscience and Biophysics (INB-3), Research Center Jülich, 52425 Jülich, Germany.
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16
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Abstract
The development of potent and selective agonists and antagonists of adenosine receptors (ARs) has been a target of medicinal chemistry research for several decades, and recently the US Food and Drug Administration has approved Lexiscan, an adenosine derivative substituted at the 2 position, for use as a pharmacologic stress agent in radionuclide myocardial perfusion imaging. Currently, some other adenosine A(2A) receptor (A(2A)AR) agonists and antagonists are undergoing preclinical testing and clinical trials. While agonists are potent antiinflammatory agents also showing hypotensive effects, antagonists are being developed for the treatment of Parkinson's disease.However, since there are still major problems in this field, including side effects, low brain penetration (for the targeting of CNS diseases), short half-life, or lack of in vivo effects, the design and development of new AR ligands is a hot research topic.This review presents an update on the medicinal chemistry of A(2A)AR agonists and antagonists, and stresses the strong need for more selective ligands at the human A(2A)AR subtype, in particular in the case of agonists.
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Affiliation(s)
- Gloria Cristalli
- Dipartimento di Scienze Chimiche, Università di Camerino, 62032 Camerino (MC), Italy.
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17
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Ye Y, Wei J, Dai X, Gao Q. Computational studies of the binding modes of A 2A adenosine receptor antagonists. Amino Acids 2008; 35:389-96. [PMID: 17978889 PMCID: PMC7087644 DOI: 10.1007/s00726-007-0604-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 09/12/2007] [Indexed: 11/25/2022]
Abstract
A molecular docking study was performed on several structurally diverse A(2A) AR antagonists, including xanthines, and non-xanthine type antagonists to investigate their binding modes with A(2A) adenosine receptor (AR), one of the four subtypes of AR, which is currently of great interest as a target for therapeutic intervention, in particular for Parkinson's disease. The high-affinity binding site was found to be a hydrophobic pocket with the involvement of hydrogen bonding interactions as well as pi-pi stacking interactions with the ligands. The detailed binding modes for both xanthine and non-xanthine type A(2A) antagonists were compared and the essential features were extracted and converted to database searchable queries for virtual screening study of novel A(2A) AR antagonists. Findings from this study are helpful for elucidating the binding pattern of A(2A) AR antagonists and for the design of novel active ligands.
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Affiliation(s)
- Y. Ye
- />School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - J. Wei
- />School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - X. Dai
- />Chemistry Department, XenoPort Inc., Santa Clara, CA U.S.A
| | - Q. Gao
- />Chemistry Department, XenoPort Inc., Santa Clara, CA U.S.A
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18
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Cristalli G, Cacciari B, Dal Ben D, Lambertucci C, Moro S, Spalluto G, Volpini R. Highlights on the development of A(2A) adenosine receptor agonists and antagonists. ChemMedChem 2008; 2:260-81. [PMID: 17177231 DOI: 10.1002/cmdc.200600193] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Although significant progress has been made in the past few decades demonstrating that adenosine modulates a variety of physiological and pathophysiological processes through the interaction with four subtypes of a family of cell-surface G-protein-coupled receptors, clinical evaluation of some adenosine receptor ligands has been discontinued. Major problems include side effects due to the wide distribution of adenosine receptors, low brain penetration (which is important for the targeting of CNS diseases), short half-life of compounds, or a lack of effects, in some cases perhaps due to receptor desensitization or to low receptor density in the targeted tissue. Currently, three A(2A) adenosine receptor agonists have begun phase III studies. Two of them are therapeutically evaluated as pharmacologic stress agents and the third proved to be effective in the treatment of acute spinal cord injury (SCI), while avoiding the adverse effects of steroid agents. On the other hand, the great interest in the field of A(2A) adenosine receptor antagonists is related to their application in neurodegenerative disorders, in particular, Parkinson's disease, and some of them are currently in various stages of evaluation. This review presents an update of medicinal chemistry and molecular recognition of A(2A) adenosine receptor agonists and antagonists, and stresses the strong need for more selective ligands at the A(2A) human subtype.
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Affiliation(s)
- Gloria Cristalli
- Dipartimento di Scienze Chimiche, Università di Camerino, Via S. Agostino 1, 62032 Camerino, Italy.
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19
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Bhagwat SS, Williams M. Patent Update Cardiovascular & Renal: Recent progress in modulators of purinergic activity. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.5.6.547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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20
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Vollmann K, Qurishi R, Hockemeyer J, Müller CE. Synthesis and properties of a new water-soluble prodrug of the adenosine A 2A receptor antagonist MSX-2. Molecules 2008; 13:348-59. [PMID: 18305423 PMCID: PMC6244838 DOI: 10.3390/molecules13020348] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 02/11/2008] [Accepted: 02/11/2008] [Indexed: 11/22/2022] Open
Abstract
The compound L-valine-3-{8-[(E)-2-[3-methoxyphenyl)ethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4) was synthesized as an amino acid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to be stable in artificial gastric acid, but readily cleaved by pig liver esterase.
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Affiliation(s)
| | | | | | - Christa E. Müller
- Pharma-Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, An der Immenburg 4, D-53121 Bonn, Germany; http://www.pharmazentrum.uni-bonn.de/ and http://www.pharma.uni-bonn.de/pharmchem/
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21
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Drabczyńska A, Müller CE, Karolak-Wojciechowska J, Schumacher B, Schiedel A, Yuzlenko O, Kieć-Kononowicz K. N9-benzyl-substituted 1,3-dimethyl- and 1,3-dipropyl-pyrimido[2,1-f]purinediones: synthesis and structure-activity relationships at adenosine A1 and A2A receptors. Bioorg Med Chem 2007; 15:5003-17. [PMID: 17499511 DOI: 10.1016/j.bmc.2007.04.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 03/30/2007] [Accepted: 04/13/2007] [Indexed: 11/25/2022]
Abstract
Synthesis and physicochemical properties of N-benzyl pyrimido[2,1-f]purinediones are described. These derivatives were synthesized by the cyclization of 7-chloropropylo-8-bromo-1,3-dimethyl- or 1,3-dipropyl xanthine derivatives with corresponding (un)substituted benzylamines. Dipropyl derivatives were obtained under microwave irradiation conditions either. The obtained compounds (1-20) were evaluated for their affinity to adenosine A1 and A2A receptors, selected compounds were additionally investigated for affinity to the A3 receptor subtype. The results of the radioligand binding assays to A1 and A2A adenosine receptors showed that most of the 1,3-dimethyl-9-benzylpyrimidopurinediones exhibited selective affinity to A2A receptors at micromolar or submicromolar concentrations (for example, derivative 9 with o-methoxy substituent displayed a Ki value of 0.699 microM at rat A2A receptor with more than 36-fold selectivity). Contrary to previously described arylpyrimido[2,1-f]purinediones dipropyl derivatives (compounds 15-20) showed affinity to both kinds of receptors increased, however A1 affinity increased to a larger extent, with the result that A2A selectivity was abolished. The best adenosine A1 receptor ligand was m-chlorobenzyl derivative 18 (Ki=0.089 microM and 5-fold A1 selectivity). Structure-activity relationships were discussed with the analysis of lipophilic and spatial properties of the investigated compounds. Pharmacophore model of adenosine A1 receptor antagonist was adopted for this purpose.
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Affiliation(s)
- Anna Drabczyńska
- Jagiellonian University, Medical College, Faculty of Pharmacy, Department of Technology and Biotechnology of Drugs, Medyczna 9, Pl 30-688 Kraków, Poland
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22
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Wei J, Wang S, Gao S, Dai X, Gao Q. 3D-Pharmacophore Models for Selective A2A and A2B Adenosine Receptor Antagonists. J Chem Inf Model 2007; 47:613-25. [PMID: 17330954 DOI: 10.1021/ci600410m] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Three-dimensional pharmacophore models were generated for A2A and A2B adenosine receptors (ARs) based on highly selective A2A and A2B antagonists using the Catalyst program. The best pharmacophore model for selective A2A antagonists (Hypo-A2A) was obtained through a careful validation process. Four features contained in Hypo-A2A (one ring aromatic feature (R), one positively ionizable feature (P), one hydrogen bond acceptor lipid feature (L), and one hydrophobic feature (H)) seem to be essential for antagonists in terms of binding activity and A2A AR selectivity. The best pharmacophore model for selective A2B antagonists (Hypo-A2B) was elaborated by modifying the Catalyst common features (HipHop) hypotheses generated from the selective A2B antagonists training set. Hypo-A2B also consists of four features: one ring aromatic feature (R), one hydrophobic aliphatic feature (Z), and two hydrogen bond acceptor lipid features (L). All features play an important role in A2B AR binding affinity and are essential for A2B selectivity. Both A2A and A2B pharmacophore models have been validated toward a wide set of test molecules containing structurally diverse selective antagonists of all AR subtypes. They are capable of identifying correspondingly high potent antagonists and differentiating antagonists between subtypes. The results of our study will act as a valuable tool for retrieving structurally diverse compounds with desired biological activities and designing novel selective adenosine receptor ligands.
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Affiliation(s)
- Jing Wei
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, P.R. China
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23
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Drabczyńska A, Müller CE, Lacher SK, Schumacher B, Karolak-Wojciechowska J, Nasal A, Kawczak P, Yuzlenko O, Pekala E, Kieć-Kononowicz K. Synthesis and biological activity of tricyclic aryloimidazo-, pyrimido-, and diazepinopurinediones. Bioorg Med Chem 2006; 14:7258-81. [PMID: 16844379 DOI: 10.1016/j.bmc.2006.06.052] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 06/20/2006] [Accepted: 06/23/2006] [Indexed: 11/24/2022]
Abstract
Syntheses and physicochemical properties of N-aryl-substituted imidazo-, pyrimido-, and 1,3-diazepino[2,1-f]purinediones are described. These derivatives were synthesized by the cyclization of 7-haloalkyl-8-bromo-1,3-dimethyl- or 1,3-dipropyl-xanthine derivatives with corresponding arylamines. The obtained compounds (1-40), which can be envisaged as sterically fixed and configurationally stable analogs of 8-styrylxanthines, were evaluated for their affinity to adenosine A(1) and A(2A) receptors, the receptor subtypes that are predominant in the brain. Selected compounds were additionally investigated for affinity to the A(2B) and A(3) receptor subtypes. Many of the compounds showed adenosine A(2A) receptor affinity at micromolar or submicromolar concentrations and were A(2A)-selective, for example, compound 23 with p-fluoro substituent displayed K(i) value of 0.147 microM at the rat A(2A) receptor and more than 170-fold-A(2A) selectivity, compound 17 with naphthyl substituent had K(i) value of 0.219 microM and a more than 114-fold-A(2A) selectivity. The compounds were somewhat weaker and less selective at the human receptor subtypes. Elongation of the dimethyl substituent to dipropyl in xanthine moiety improved affinity but reduced selectivity. 1,3-Dimethylimidazo-, pyrimido-, and diazepinopurinediones were evaluated in vivo as anticonvulsants in MES, ScMet, TTE tests and examined for neurotoxicity in mice (ip). Substances with pyrimido ring displayed protective activity in ScMet or in MES and ScMet tests, showing also neurotoxicity. The pyrimidine annelated ring is beneficial for both receptor affinity and anticonvulsant activity.
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Affiliation(s)
- Anna Drabczyńska
- Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, Pl 30-688 Kraków, Poland
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24
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Moro S, Gao ZG, Jacobson KA, Spalluto G. Progress in the pursuit of therapeutic adenosine receptor antagonists. Med Res Rev 2006; 26:131-59. [PMID: 16380972 PMCID: PMC9194718 DOI: 10.1002/med.20048] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ever since the discovery of the hypotensive and bradycardiac effects of adenosine, adenosine receptors continue to represent promising drug targets. First, this is due to the fact that the receptors are expressed in a large variety of tissues. In particular, the actions of adenosine (or methylxanthine antagonists) in the central nervous system, in the circulation, on immune cells, and on other tissues can be beneficial in certain disorders. Second, there exists a large number of ligands, which have been generated by introducing several modifications in the structure of the lead compounds (adenosine and methylxanthine), some of them highly specific. Four adenosine receptor subtypes (A1, A2A, A2B, and A3) have been cloned and pharmacologically characterized, all of which are G protein-coupled receptors. Adenosine receptors can be distinguished according to their preferred mechanism of signal transduction: A1 and A3 receptors interact with pertussis toxin-sensitive G proteins of the Gi and Go family; the canonical signaling mechanism of the A2A and of the A2B receptors is stimulation of adenylyl cyclase via Gs proteins. In addition to the coupling to adenylyl cyclase, all four subtypes may positively couple to phospholipase C via different G protein subunits. The development of new ligands, in particular, potent and selective antagonists, for all subtypes of adenosine receptors has so far been directed by traditional medicinal chemistry. The availability of genetic information promises to facilitate understanding of the drug-receptor interaction leading to the rational design of a potentially therapeutically important class of drugs. Moreover, molecular modeling may further rationalize observed interactions between the receptors and their ligands. In this review, we will summarize the most relevant progress in developing new therapeutic adenosine receptor antagonists.
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Affiliation(s)
- Stefano Moro
- Molecular Modeling Section, Dipartimento di Scienze Farmaceutiche, Università di Padova, Via Marzolo 5, I-35131 Padova, Italy.
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25
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Holschbach MH, Bier D, Wutz W, Sihver W, Schüller M, Olsson RA. Derivatives of 4,6-diamino-1,2-dihydro-2-phenyl-1,2,4-triazolo[4,3-a]quinoxalin-2H-1-one: potential antagonist ligands for imaging the A2A adenosine receptor by positron emission tomography (PET). Eur J Med Chem 2005; 40:421-37. [PMID: 15893016 DOI: 10.1016/j.ejmech.2004.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Revised: 12/20/2004] [Accepted: 12/21/2004] [Indexed: 10/25/2022]
Abstract
The importance of the brain A2A adenosine receptor (A(2A)AR) in movement disorders urges the development of radiolabeled ligands for imaging those receptors by positron emission tomography (PET). This study evaluated one class of A(2A)AR antagonists, derivatives of 4-amino-6-benzylamino-1,2-dihydro-2-phenyl-1,2,4-triazolo[4,3-a]quinoxalin-2H-1-one, 10a, as agents for imaging brain A(2A)ARs by PET.. Modifications of a literature synthesis of 10a efficiently generated analogs 10b-s for pharmacological evaluation. Radioligand binding experiments showed affinities for the rat brain A(2A)AR in the low nanomolar range but similar affinities for the A1AR and substantial unspecific binding. Autoradiography employing [3H]10a, showing that high unspecific binding obscured specific binding to both the A1AR and A(2A)AR. Thus, compounds 10b-s are unsuitable as ligands for imaging brain A(2A)ARs by PET.
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Affiliation(s)
- Marcus H Holschbach
- Institut für Nuklearchemie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
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26
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Hockemeyer J, Burbiel JC, Müller CE. Multigram-scale syntheses, stability, and photoreactions of A2A adenosine receptor antagonists with 8-styrylxanthine structure: potential drugs for Parkinson's disease. J Org Chem 2004; 69:3308-18. [PMID: 15132536 DOI: 10.1021/jo0358574] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The improved multigram-scale syntheses of the important 8-styrylxanthine A(2A) adenosine receptor antagonist MSX-2 (8), its water-soluble prodrug MXS-3 (9), and KW-6002 (16) are described. N-Alkylation reactions at different positions of uracil derivatives were optimized. Two different methods for xanthine formation from 6-amino-5-cinnamoylaminouracil precursors were investigated, (a) the elimination of water by alkaline catalysis and (b) hexamethyldisilazane as a condensing agent; the latter was found to be superior. The photosensitivity of 8-styrylxanthines was studied. The (E)-configurated stryrylxanthine MSX-2 (8) isomerized in diluted solution, and the resulting (Z)-isomer (10a) was isolated and characterized. Furthermore, we describe for the first time that solid 8-styrylxanthines can dimerize upon exposition to daylight or irradiation with UV light. The resulting cyclobutane derivatives with head-to-tail (syn) configuration exhibited a considerably lower A(2A) adenosine receptor affinity than their parent compounds. The dimerization product of MSX-2 was a moderately potent nonselective A(1) and A(2A) antagonist (K(i)(A(1)) = 273 nM, K(i) (A(2A)) = 175 nM) while the dimer of the related compound KW-6002 was inactive at A(1) and only weakly active at A(2A) adenosine receptors (K(i) = 1.57 microM). The light sensitivity of 8-styrylxanthine derivatives, not only in solution, but also in the solid state, has to be considered when using those compounds as pharmacological tools or drugs.
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Affiliation(s)
- Jörg Hockemeyer
- University of Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry Poppelsdorf, Kreuzbergweg 26, D-53115 Bonn, Germany
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27
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Ishiwata K, Wang WF, Kimura Y, Kawamura K, Ishii K. Preclinical studies on [11C]TMSX for mapping adenosine A2A receptors by positron emission tomography. Ann Nucl Med 2003; 17:205-11. [PMID: 12846542 DOI: 10.1007/bf02990023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
In previous in vivo studies with mice, rats and monkeys, we have demonstrated that [11C]TMSX ([7-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine) is a potential radioligand for mapping adenosine A2A receptors of the brain by positron emission tomography (PET). In the present study, we performed a preclinical study. A suitable preparation method for [11C]TMSX injection was established. The radiation absorbed-dose by [11C]TMSX in humans estimated from the tissue distribution in mice was low enough for clinical use, and the acute toxicity and mutagenicity of TMSX were not found. The striatal uptake of [11C]TMSX in mice was reduced by pretreatment with theophylline at the dose of 10 and 100 mg/kg, suggesting that the [11C]TMSX PET should be carefully performed in the patients received with theophylline. We have concluded that [11C]TMSX is suitable for mapping adenosine A2A receptors in the human brain by PET.
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Affiliation(s)
- Kiichi Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Japan.
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28
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Petzer JP, Steyn S, Castagnoli KP, Chen JF, Schwarzschild MA, Van der Schyf CJ, Castagnoli N. Inhibition of monoamine oxidase B by selective adenosine A2A receptor antagonists. Bioorg Med Chem 2003; 11:1299-310. [PMID: 12628657 DOI: 10.1016/s0968-0896(02)00648-x] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Adenosine receptor antagonists that are selective for the A(2A) receptor subtype (A(2A) antagonists) are under investigation as possible therapeutic agents for the symptomatic treatment of the motor deficits associated with Parkinson's disease (PD). Results of recent studies in the MPTP mouse model of PD suggest that A(2A) antagonists may possess neuroprotective properties. Since monoamine oxidase B (MAO-B) inhibitors also enhance motor function and reduce MPTP neurotoxicity, we have examined the MAO-B inhibiting properties of several A(2A) antagonists and structurally related compounds in an effort to determine if inhibition of MAO-B may contribute to the observed neuroprotection. The results of these studies have established that all of the (E)-8-styrylxanthinyl derived A(2A) antagonists examined display significant MAO-B inhibitory properties in vitro with K(i) values in the low micro M to nM range. Included in this series is (E)-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methylxanthine (KW-6002), a potent A(2A) antagonist and neuroprotective agent that is in clinical trials. The results of these studies suggest that MAO-B inhibition may contribute to the neuroprotective potential of A(2A) receptor antagonists such as KW-6002 and open the possibility of designing dual targeting drugs that may have enhanced therapeutic potential in the treatment of PD.
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Affiliation(s)
- Jacobus P Petzer
- Department of Chemistry, Virginia Tech, Blacksburg, VA 24061-0212, USA
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29
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Harada H, Asano O, Hoshino Y, Yoshikawa S, Matsukura M, Kabasawa Y, Niijima J, Kotake Y, Watanabe N, Kawata T, Inoue T, Horizoe T, Yasuda N, Minami H, Nagata K, Murakami M, Nagaoka J, Kobayashi S, Tanaka I, Abe S. 2-Alkynyl-8-aryl-9-methyladenines as novel adenosine receptor antagonists: their synthesis and structure-activity relationships toward hepatic glucose production induced via agonism of the A(2B) receptor. J Med Chem 2001; 44:170-9. [PMID: 11170626 DOI: 10.1021/jm990499b] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Novel adenosine antagonists, 2-alkynyl-8-aryl-9-methyladenine derivatives, were synthesized as candidate hypoglycemic agents. These analogues were evaluated for inhibitory activity on N-ethylcarboxamidoadenosine (NECA)-induced glucose production in primary cultured rat hepatocytes. In general, aromatic moieties at the 8-position and alkynyl groups at the 2-position had significantly increased activity compared to unsubstituted compounds. The preferred substituents at the 8-position of adenine were the 2-furyl and 3-fluorophenyl groups. In modifying the alkynyl side chain, change of the ring size, cleavage of the ring, and removal of the hydroxyl group were well tolerated. The order of the stimulatory effects of adenosine agonists on rat hepatocytes was NECA > CPA > CGS21680, which is consistent with involvement of the A(2B) receptor. In Chinese hamster ovary cells stably transfected with human A(2B) receptor cDNA, one of the compounds potent in hepatocytes, 15o (IC(50) = 0.42 microM), antagonized NECA-induced stimulation of cyclic AMP production (IC(50) = 0.063 microM). This inhibitory effect was much more potent than those of FK453, KF17837, and L249313 which have been reported to be respectively A(1), A(2A), and A(3) selective antagonists. These findings agree very well with the result that, compared to 15o, these selective antagonists for each receptor subtype showed only marginal effects in rat hepatocytes. These results suggest that adenosine agonist-induced glucose production in rat hepatocytes is mediated through the A(2B) receptor. Furthermore, 15o showed hypoglycemic activity in an animal model of noninsulin-dependent diabetes mellitus, the KK-A(y) mice. It is possible that inhibition of hepatic glucose production via the A(2B) receptor could be at least one of the mechanisms by which 15o exerts its in vivo effects. Further elaboration of this group of compounds may afford novel antidiabetic agents.
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Affiliation(s)
- H Harada
- Tsukuba Research Laboratories, Eisai Company, Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635, Japan.
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30
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Wang WF, Ishiwata K, Nonaka H, Ishii S, Kiyosawa M, Shimada J, Suzuki F, Senda M. Carbon-11-labeled KF21213: a highly selective ligand for mapping CNS adenosine A(2A) receptors with positron emission tomography. Nucl Med Biol 2000; 27:541-6. [PMID: 11056367 DOI: 10.1016/s0969-8051(00)00126-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In vivo assessment of the adenosine A(2A) receptors localized in the striatum with positron emission tomography (PET) may offers us a new diagnostic tool for neurological disorders. We evaluated the potential of [7-methyl-(11)C](E)-8-(2,3-dimethyl-4-methoxystyryl)-1, 3,7-trimethylxanthine ([(11)C]KF21213) as a PET ligand for mapping adenosine A(2A) receptors in the central nervous system. KF21213 showed a high affinity for the adenosine A(2A) receptors in vitro (Ki = 3.0 nM) and a very low affinity for the A(1) receptors (Ki > 10,000 nM). In mice, the striatal uptake of [(11)C]KF21213 increased for the first 15 min and then gradually decreased, whereas the uptake in the reference regions such as the cortex and cerebellum rapidly decreased. The uptake ratio of striatum to cortex and striatum to cerebellum increased to 8.6 and 10.5, respectively, at 60 min postinjection. The striatal uptake was significantly blocked by co-injection of carrier KF21213 or each of three other A(2A) antagonists, but not by co-injection of A(1) antagonist. The specific uptake was not detected in the cortex or in the cerebellum. Ex vivo autoradiography and PET clearly visualized adenosine A(2A) receptors in the rat striatum. [(11)C]KF21213 was the most selective tracer for mapping adenosine A(2A) in the central nervous system by PET among the tracers proposed to date.
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Affiliation(s)
- W F Wang
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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31
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Ishiwata K, Ogi N, Shimada J, Nonaka H, Tanaka A, Suzuki F, Senda M. Further characterization of a CNS adenosine A2a receptor ligand [11C]KF18446 with in vitro autoradiography and in vivo tissue uptake. Ann Nucl Med 2000; 14:81-9. [PMID: 10830524 DOI: 10.1007/bf02988585] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PET assessment of the adenosine A2a receptors localized in the striatum offers us a potential new diagnostic tool for neurological disorders. In the present study, we carried out in vitro receptor autoradiography of a newly developed PET ligand [11C]KF18446 ([7-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthin e) with rat brain sections. [11C]KF18446 showed a high striatum/cortex binding ratio (5.0) and low nonspecific binding (<10%), suggesting that [11C]KF18446 has characteristics comparable or slightly superior to [3H]CGS 21680 or [3H]SCH 58261, which are currently available representative A2a receptor ligands. Scatchard analysis indicated a Kd of 9.8 nM and a Bmax of 170 fmol/mm3 tissue in the striatum and a Kd of 16.4 nM and a Bmax of 33 fmol/mm3 tissue in the cortex. Seven xanthine-type and four nonxanthine-type adenosine receptor ligands with an affinity for the adenosine A2a receptors significantly reduced the in vitro binding of [11C]KF18446 to the brain section. The blocking effects were much stronger in the striatum than in the cortex, but did not necessarily parallel their affinity. On the other hand, four xanthine-type ligands and one nonxanthine-type ligand (SCH 58261) of the 11 ligands studied reduced the in vivo uptake of [11C]KF18446 in mice, but other ligands, including A1-selective and nonselective ligands and three nonxanthine-type A2a-selective antagonists did not. We conclude that [11C]KF18446 is a promising adenosine A2a receptor ligand for PET study.
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Affiliation(s)
- K Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Japa.
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32
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[11C]-labeling of some caffeine derivatives for mapping adenosine A2a receptors by PET technique. J Radioanal Nucl Chem 1999. [DOI: 10.1007/bf02345557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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Márián T, Boros I, Lengyel Z, Balkay L, Horváth G, Emri M, Sarkadi E, Szentmiklósi AJ, Fekete I, Trón L. Preparation and primary evaluation of [11C]CSC as a possible tracer for mapping adenosine A2A receptors by PET. Appl Radiat Isot 1999; 50:887-93. [PMID: 10214707 DOI: 10.1016/s0969-8043(98)00162-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A 11C labeled selective adenosine A2A antagonist, (E)-8-(3-chlorostyryl)-1,3-dimethyl-7-[11C]methylxanthine [11C]CSC) was prepared by the reaction of (E)-8-(3-chlorostyryl)-1,3-dimethylxanthine and [11C]methyl iodide. The decay-corrected radiochemical yield was 32.3% with a radiochemical purity of 99%, a specific activity of 1.85-5.55 GBq/mumol and a preparation time of 1 h. A primary evaluation of [11C]CSC as a potential tracer for mapping adenosine A2A receptors by positron emission tomography (PET) is also presented. Biodistribution and autoradiographic studies were carried out on Swiss mice and domestic rabbits. In mice the lung showed the highest uptake at 10 min after i.v. injection, followed by the liver, kidney, heart and brain. Inside the brain a high level of radioactivity accumulated in the striatum, in accordance with previous findings on the specific spatial distribution of A2A adenosine receptors and also in the medulla oblongata. Dynamic PET studies on rabbits showed a fast brain uptake of CSC, reaching a maximum in less then 2 min. On the basis of competition experiments with the unlabeled ligand [11C]CSC proves to bind specifically to the appropriate receptor.
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Affiliation(s)
- T Márián
- PET Centre, University Medical School of Debrecen, Hungary
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Baraldi PG, Borea PA, Bergonzoni M, Cacciari B, Ongini E, Recanatini M, Spalluto G. Comparative molecular field analysis (CoMFA) of a series of selective adenosine receptor A2A antagonists. Drug Dev Res 1999. [DOI: 10.1002/(sici)1098-2299(199902)46:2<126::aid-ddr5>3.0.co;2-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Baraldi PG, Cacciari B, Dionisotti S, Egan J, Spalluto G, Zocchi C. Synthesis of the tritium labeled SCH 58261, a new non-xanthine A2A adenosine receptor antagonist. J Labelled Comp Radiopharm 1998. [DOI: 10.1002/(sici)1099-1344(199608)38:8<725::aid-jlcr885>3.0.co;2-g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Müller CE, Sandoval-Ramírez J, Schobert U, Geis U, Frobenius W, Klotz KN. 8-(Sulfostyryl)xanthines: water-soluble A2A-selective adenosine receptor antagonists. Bioorg Med Chem 1998; 6:707-19. [PMID: 9681137 DOI: 10.1016/s0968-0896(98)00025-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
8-(Sulfostyryl)xanthine derivatives were synthesized as water-soluble A2A-selective adenosine receptor (AR) antagonists. meta- and para-sulfostyryl-DMPX (3,7-dimethyl-1-propargylxanthine) derivatives 11a and 11b exhibited high affinity to rat A2A-AR in submicromolar concentrations, and were 20- to 30-fold selective versus rat A1-AR. Styryl-DMPX derivatives were inactive at human A2B- and A3-AR. 1,3-Dipropyl-8-p-sulfostyrylxanthine (13) or only a 7-methyl derivative (14) showed similar (13) or higher (14) A2A affinity than 11a and 11b but showed no (13) or only a low degree (14) of selectivity versus A1-, A2B-, and A3-AR. The A2A-selective sulfostyryl-DMPX derivatives exhibit high water-solubility and may be useful research tools for in vivo studies.
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Affiliation(s)
- C E Müller
- Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität Würzburg, Pharmazeutische Chemie, Germany.
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Abstract
This review summarises current knowledge on adenosine receptors, an important G protein-coupled receptor. The four known adenosine receptor subtypes A1, A2A, A2B, and A3 are discussed with special reference to the opportunities for drug development.
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Affiliation(s)
- S A Poulsen
- Queensland Pharmaceutical Research Institute, Griffith University, Brisbane, Australia
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Müller CE, Geis U, Hipp J, Schobert U, Frobenius W, Pawłowski M, Suzuki F, Sandoval-Ramírez J. Synthesis and structure-activity relationships of 3,7-dimethyl-1-propargylxanthine derivatives, A2A-selective adenosine receptor antagonists. J Med Chem 1997; 40:4396-405. [PMID: 9435909 DOI: 10.1021/jm970515+] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A series of 8-substituted derivatives of 3,7-dimethyl-1-propargylxanthine (DMPX) was synthesized and investigated as A2A adenosine receptor antagonists. Different synthetic strategies for the preparation of DMPX derivatives and analogues were explored. A recently developed synthetic procedure starting from 3-propargyl-5,6-diaminouracil proved to be the method of choice for the preparation of this type of xanthine derivatives. The novel compounds were investigated in radioligand binding studies at the high-affinity adenosine receptor subtypes A1 and A2A and compared with standard A2A adenosine receptor antagonists. Structure-activity relationships were analyzed in detail. 8-Styryl-substituted DMPX derivatives were identified that exhibit high affinity and selectivity for A2A adenosine receptors, including 8-(m-chlorostyryl)-DMPX (CS-DMPX, Ki A2A = 13 nM, 100-fold selective), 8-(m-bromostyryl)-DMPX (BS-DMPX, Ki A2A = 8 nM, 146-fold selective), and 8-(3,4-dimethoxystyryl)-DMPX (Ki A2A = 15 nM, 167-fold selective). These and other novel compounds are superior to the standard A2A adenosine receptor antagonists KF17837 (4) and CSC (5) with respect to A2A affinity and/or selectivity.
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Affiliation(s)
- C E Müller
- Julius-Maximilians-Universität Würzburg, Institut für Pharmazie und Lebensmittelchemie, Pharmazeutische Chemie, Germany.
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Abstract
The adenosine A2A receptor subtype is one of the four adenosine receptors that have been identified in the mammalian organism. In addition to being found in blood vessels, platelets and polymorphonuclear leukocytes, the A2A receptors are abundant in the central nervous system, especially in the striatum. The recent development of selective A2A receptor ligands, in particular of receptor antagonists, makes it possible to elucidate the function of A2A receptors in normal and altered conditions. Pharmacological studies have shown that A2A receptor antagonists are potentially effective for treatment of neurodegenerative processes such as Parkinson's disease. Their activity is attributed to the close anatomical and functional links between A2A receptors and dopaminergic pathways in the basal ganglia. More recently, A2A receptor antagonists have proved to be active in models of cerebral ischemia. While the mechanisms underlying the role of A2A receptors in the hypoxia/ ischemia processes remains to be clarified, it is recognized that A2A receptor antagonists counteract the effects of excitatory aminoacids, which are massively released after cerebral ischemia. Another function of A2A receptors is related to protection from seizures, but further studies are needed to elucidate their specific interaction, if any, with neuronal excitability. Altogether, the great advance recently made with the discovery of selective A2A receptor ligands provides increasing information on the function of A2A receptors and opens new perspectives for treatment of neurological disorders.
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Affiliation(s)
- E Ongini
- Schering-Plough Research Institute, Milan, Italy.
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Shimada J, Koike N, Nonaka H, Shiozaki S, Yanagawa K, Kanda T, Kobayashi H, Ichimura M, Nakamura J, Kase H, Suzuki F. Adenosine A2A antagonists with potent anti-cataleptic activity. Bioorg Med Chem Lett 1997. [DOI: 10.1016/s0960-894x(97)00440-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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41
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Müller CE, Schobert U, Hipp J, Geis U, Frobenius W, Pawlowski M. Configurationally stable analogs of styrylxanthines as A2A adenosine receptor antagonist. Eur J Med Chem 1997. [DOI: 10.1016/s0223-5234(97)88913-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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42
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Ishiwata K, Sakiyama Y, Sakiyama T, Shimada J, Toyama H, Oda K, Suzuki F, Senda M. Myocardial adenosine A2a receptor imaging of rabbit by PET with [11C]KF17837. Ann Nucl Med 1997; 11:219-25. [PMID: 9310171 DOI: 10.1007/bf03164767] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Adenosine A2a receptors are found in the endothelia, vascular smooth muscle cells and cardiac myocytes. The properties of a carbon-11 labeled A2a antagonist [11C]KF17837 ([7-methyl-11C](E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-methy lxa nthine) for myocardial imaging were evaluated by dynamic PET scanning of the myocardium in rabbits. Myocardial uptake of [11C]KF17837 was clearly visualized by PET. The tracer was taken up at a high level by the myocardium immediately after the injection, and the myocardial level of radioactivity gradually decreased. On the other hand, an inactive [11C]Z-isomer of [11C]KF17837 showed a very low myocardial uptake and the myocardium was not visualized with a selective A1 antagonist [11C]KF15372. By co-injection with carrier KF17837 or a xanthine type A2a antagonist 7-chlorostyrylcaffeine (CSC), the myocardial uptake of [11C]KF17837 was completely blocked. The effect of non-xanthine A2a antagonists ZM 241,385 and SCH 58,261, which have a higher affinity than CSC, was smaller than that of the CSC. The effect of weak antagonists caffeine and alloxazine or a xanthine type A1 antagonist KF15372 on the radioactivity level was small. It is concluded that PET with [11C]KF17837 can image myocardial adenosine A2a receptors.
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Affiliation(s)
- K Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Japan.
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43
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Müller CE, Sauer R, Geis U, Frobenius W, Talik P, Pawlowski M. Aza-analogs of 8-styrylxanthines as A2A-adenosine receptor antagonists. Arch Pharm (Weinheim) 1997; 330:181-9. [PMID: 9264243 DOI: 10.1002/ardp.19973300606] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the present study we synthesized aza-analogs of 8-styrylxanthines, in which the ethenyl bridge is replaced by an imine, amide, or azo function, in order to investigate structure-activity relationships of the 8-substituent of A2A-selective xanthine derivatives. Thus, various 8-substituents were combined with theophylline or caffeine, respectively, and affinities of the novel compounds for adenosine A1- and A2a-receptors were determined and compared with those of analogous 8-styrylxanthine derivatives. 8-(Benzylideneamino)caffeine derivatives exhibited high affinity and selectivity for A2A-adenosine receptors, but were unstable in aqueous buffer solution at physiological pH values. 8-(Phenylazo)caffeine derivatives were less potent than corresponding 8-styrylcaffeine derivatives at adenosine receptors. The most potent azo compound of the present series was 8-(m-chlorophenylazo)caffeine (14b) exhibiting a Ki value of 400 nM at A2A-adenosine receptors and 20-fold selectivity versus A1-receptors. Due to the facile synthetic access to 8-(phenylazo)xanthine derivatives, which are obtained by coupling of 8-unsubstituted xanthines with phenyldiazonium salts, 14b may be an interesting new lead compound for the development of more potent and selective A2A-antagonists with azo structure.
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Affiliation(s)
- C E Müller
- Julius-Maximilians-Universität Würzberg, Institut für Pharmazie und Lebensmittelchemie, Germany
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44
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Stone-Elander S, Thorell JO, Eriksson L, Fredholm BB, Ingvar M. In vivo biodistribution of [N-11C-methyl]KF 17837 using 3-D-PET: evaluation as a ligand for the study of adenosine A2A receptors. Nucl Med Biol 1997; 24:187-91. [PMID: 9089711 DOI: 10.1016/s0969-8051(96)00216-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
(KF 17837, (E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-methylxanthine, was 11C-labelled by methylation at N-7 of the nor-compound, KF 17440, using [11C]methyl iodide. Radiochemical conversions of 50% or 70-80% were obtained using sodium hydride or potassium carbonate, respectively, as base. Total synthesis time was 40-45 min, including isolation by semipreparative liquid chromatography. Cerebral uptake of [N-11C-methyl]KF 17837 in Cynomolgus monkeys, evaluated using positron emission tomography (PET), was so low that regional differences in distribution kinetics were revealed first after increasing injected dose 3-fold and using 3-D mode of data acquisition. At all times, the relative regional retention (maximum striatum:cerebellum: cortex approximately 1.1:1:0.8 at 20 min) was considerably different from the known relative density of A2A receptors in these regions. Radioactivity decreased more rapidly in the cortex than in the striatum and cerebellum (by 20% vs. 3-7%, respectively, between 5 and 50 min). Addition of carrier to [N-11C-methyl]KF 17837 only marginally affected the cerebral radiotracer uptake. By contrast, in the heart the initial tracer uptake was high and the elimination kinetics was enhanced by adding unlabelled carrier. We have thus shown that KF 17837 passes the blood-brain barrier, though to a very low extent. This fact and the apparently high nonspecific binding in vivo of [N-11C-methyl]KF 17837 in regions with low receptor densities limits its usefulness as a ligand for quantification of the adenosine A2A receptors in the primate brain.
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45
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Jiang JL, van Rhee AM, Melman N, Ji XD, Jacobson KA. 6-phenyl-1,4-dihydropyridine derivatives as potent and selective A3 adenosine receptor antagonists. J Med Chem 1996; 39:4667-75. [PMID: 8917655 PMCID: PMC10788693 DOI: 10.1021/jm960457c] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
An approach to designing dihydropyridines that bind to adenosine receptors without binding to L-type calcium channels has been described. 1,4-Dihydropyridine derivatives substituted with beta-styryl or phenylethynyl groups at the 4-position and aryl groups at the 6-position were synthesized and found to be selective for human A3 receptors. Combinations of methyl, ethyl, and benzyl esters were included at the 3- and 5-positions. Affinity was determined in radioligand binding assays at rat brain A1 and A2A receptors using [3H]-(R)-PIA [[3H]-(R)-N6-(phenylisopropyl)adenosine] and [3H]CGS 21680 [[3H]-2-[[4-(2-carboxyethyl)phenyl]ethylamino]-5'- (N-ethylcarbamoyl)adenosine], respectively. Affinity was determined at cloned human and rat A3 receptors using [125I]AB-MECA [N6-(4-amino-3-iodobenzyl)-5'-(N-ethylcarbamoyl)-adenosine]. Structure-activity analysis indicated that substitution of the phenyl ring of the beta-styryl group but not of the 6-phenyl substituent was tolerated in A3 receptor selective agents. Replacement of the 6-phenyl ring with a 3-thienyl or 3-furyl group reduced the affinity at A3 receptors by 4- and 9-fold, respectively. A 5-benzyl ester 4-trans-beta-styryl derivative, 26, with a Ki value of 58.3 nM at A3 receptors, was > 1700-fold selective vs either A1 receptors or A2A receptors. Shifting the benzyl ester to the 3-position lowered the affinity at A3 receptors 3-fold. A 5-benzyl, 3-ethyl ester 4-phenylethynyl derivative, 28, displayed a Ki value of 31.4 nM at A3 receptors and 1300-fold selectivity vs A1 receptors. The isomeric 3-benzyl, 5-ethyl diester was > 600-fold selective for A3 receptors. Oxidation of 28 to the corresponding pyridine derivative reduced affinity at A3 receptors by 88-fold and slightly increased affinity at A1 receptors.
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Affiliation(s)
- Ji-long Jiang
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810
| | - A. Michiel van Rhee
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810
| | - Neli Melman
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810
| | - Xiao-duo Ji
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810
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47
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Nagashima K, Karasawa A. Modulation of erythropoietin production by selective adenosine agonists and antagonists in normal and anemic rats. Life Sci 1996; 59:761-71. [PMID: 8761029 DOI: 10.1016/0024-3205(96)00362-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hypoxia or anemia is the fundamental stimulus for erythropoietin (EPO) production. Recent in vitro studies suggest that EPO secretion in response to hypoxia is regulated by adenosine in the kidney. In order to examine the in vivo effect of adenosine on EPO production, we determined the effects of adenosine receptor agonists and antagonists on serum EPO concentration in normal and anemic rats. In normal rats, intravenous injection of adenosine agonists (NECA, CHA and CGS-21680) dose-dependently stimulated EPO production. Pretreatment with KW-3902, an adenosine A1 antagonist with modest A2b antagonistic action, or KF17837, an adenosine A2a antagonist, inhibited the NECA (0.1 mg/kg, i.v.)-stimulated EPO production. Anemic hypoxia, induced by 2% (v/w body weight) blood withdrawal, increased serum EPO concentration from 38 +/- 2 to 352 +/- 76 mU/ml, with the increased serum adenosine concentration in the renal vein. KF17837 (0.1 mg/kg, i.v.), but not KW-3902 (0.1 mg/kg, i.v.), inhibited the anemic hypoxia-induced increase in EPO production. The present findings support the notion that adenosine mediates the EPO production in response to hypoxia in the kidney.
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Affiliation(s)
- K Nagashima
- Department of Pharmacology, Kyowa Hakko Kogyo Co., Ltd., Shizuoka, Japan
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48
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Satoh S, Matsumura H, Suzuki F, Hayaishi O. Promotion of sleep mediated by the A2a-adenosine receptor and possible involvement of this receptor in the sleep induced by prostaglandin D2 in rats. Proc Natl Acad Sci U S A 1996; 93:5980-4. [PMID: 8650205 PMCID: PMC39174 DOI: 10.1073/pnas.93.12.5980] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A 6-hr continuous infusion of 2-[p-(2-carboxyethyl)phenylethylamino]-5'-N-ethylcarboxamidoadenos ine (CGS21680), a selective A2a-adenosine agonist, into the subarachnoid space underlying the ventral surface region of the rostral basal forebrain, which has been defined as the prostaglandin (PG) D2-sensitive sleep-promoting zone, at rates of 0.02, 0.2, 2.0, and 12 pmol/min increased slow-wave sleep (SWS) and paradoxical sleep (PS) in a dose-dependent manner up to 183% and 202% of their respective baseline levels. The increments produced by the infusion of CGS21680 at 0.2 and 2.0 pmol/min were totally diminished when the rats had been pretreated with an i.p. injection of (E)-1,3-dipropyl-7-methyl-8-(3,4-dimethoxystyryl)xanthine (KF17837; 30 mg/kg of body weight), a selective A2-adenosine antagonist. In contrast, the infusion of N6-cyclohexyladenosine (CHA), a selective A1-adenosine agonist, at 2 pmol/min significantly suppressed SWS before causing an increase in SWS, and a decrease in PS was also markedly visible. Essentially the same effects of CGS21680 and CHA were observed when these compounds were administered to the parenchymal region of the rostral basal forebrain through chronically implanted microdialysis probes. Thus, we clearly showed that stimulation of A2a-adenosine receptors in the rostral basal forebrain promotes SWS and PS. Furthermore, i.p. injections of KF17837 at 30 and 100 mg/kg of body weight dose-dependently attenuated the magnitude of the SWS increase produced by the infusion of PGD2 into the subarachnoid space of the sleep-promoting zone, thus indicating that the A2a-adenosine receptors are crucial in the sleep-promoting process triggered by PGD2.
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Affiliation(s)
- S Satoh
- Department of Molecular Behavorial Biology, Osaka Bioscience Institute, Japan
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49
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Ishiwata K, Noguchi J, Toyama H, Sakiyama Y, Koike N, Ishii S, Oda K, Endo K, Suzuki F, Senda M. Synthesis and preliminary evaluation of [11C]KF17837, a selective adenosine A2A antagonist. Appl Radiat Isot 1996; 47:507-11. [PMID: 8673072 DOI: 10.1016/0969-8043(95)00295-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
An 11C-labeled selective adenosine A2A antagonist, (E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-[11C]-methylxanthine ([11C]KF17837), was prepared by reaction of (E)-8-(3,4-dimethoxystyryl)-1,3-dipropylxanthine and [11C]methyl iodide with decay-corrected radiochemical yield of 19-50%, radiochemical purity of > 99%, sp. act. of 17-100 GBq/mumol and preparation time of 20-25 min. In mice, the myocardium showed the highest (13.4% ID/g) at 5 min after i.v. injection, which decreased gradually with time. The specific myocardial uptake was visualized by gamma-camera. In the brain region the radioactivity level was higher in the A2A receptors-rich striatum than in the cortex and cerebellum. The specific striatal uptake in rats was clearly demonstrated by PET. These results have shown that [11C]KF17837 is a potential PET radioligand for mapping the adenosine A2A receptors in the heart and brain.
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Affiliation(s)
- K Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo
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50
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Zocchi C, Ongini E, Ferrara S, Baraldi PG, Dionisotti S. Binding of the radioligand [3H]-SCH 58261, a new non-xanthine A2A adenosine receptor antagonist, to rat striatal membranes. Br J Pharmacol 1996; 117:1381-6. [PMID: 8730729 PMCID: PMC1909468 DOI: 10.1111/j.1476-5381.1996.tb15296.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
1. The present study describes the binding to rat striatal A2A adenosine receptors of the new potent and selective antagonist radioligand, [3H]-5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo[4,3-e]-1,2,4-triazol o [1,5-c] pyrimidine, [3H]-SCH 58261. 2. [3H]-SCH 58261 specific binding to rat striatal membranes ( > 90%) was saturable, reversible and dependent upon protein concentration. Saturation experiments revealed that [3H]-SCH 58261 labelled a single class of recognition sites with high affinity (Kd = 0.70 nM) and limited capacity (apparent Bmax = 971 fmol mg-1 of protein). The presence of 100 microM GTP in the incubation mixture did not modify [3H]-SCH 58261 binding parameters. 3. Competition experiments showed that [3H]-SCH 58261 binding is consistent with the labelling of A2A striatal receptors. Adenosine receptor agonists competed with the binding of 0.2 nM [3H]-SCH 58261 with the following order of potency: 2-hexynyl-5'-N-ethyl carboxamidoadenosine (2HE-NECA) > 5'-N-ethylcarboxamidoadenosine (NECA) > 2-[4-(2-carboxyethyl)-phenethylamino]-5'-N-ethylcarboxamidoadenosi ne (CGS 21680) > 2-phenylaminoadenosine (CV 1808) > R-N6-phenylisopropyladenosine (R-PIA) > N6-cyclohexyladenosine (CHA) = 2-chloro-N6-cyclopentyladenosine (CCPA) > S-N6-phenylisopropyladenosine (S-PIA). 4. Adenosine antagonists inhibited [3H]-SCH 58261 binding with the following order: 5-amino-9-chloro-2-(2-furyl)-[1,2,4]-triazolo[1,5-c] quinazoline (CGS 15943) > 5-amino-8-(4-fluorobenzyl)-2-(2-furyl)-pyrazolo [4,3-e]-1,2,4-triazolo [1,5-c] pyrimidine (8FB-PTP) = SCH 58261 > xanthine amine congener (XAC) = (E,18%-Z,82%)7-methyl-8-(3,4-dimethoxystyryl)-1,3-dipropylxanthine (KF 17837S) > 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) > or = 8-phenyltheophylline (8-PT). 5. The Ki values for adenosine antagonists were similar to those labelled with the A2A agonist [3H]-CGS 21680. Affinities of agonists were generally lower. The A1-selective agonist, R-PIA, was found to be about 9 fold more potent than its stereoisomer, S-PIA, thus showing the stereoselectivity of [3H]-SCH 58261 binding. Except for 8-PT, the adenosine agonists and antagonists examined inhibited [3H]-SCH 58261 binding with Hill coefficients not significantly different from unity. 6. The present results indicate that [3H]-SCH 58261 is the first non-xanthine adenosine antagonist radioligand which directly labels A2A striatal receptors. High receptor affinity, good selectivity and very low non-specific binding make [3H]-SCH 58261 an excellent probe for studying the A2A adenosine receptor subtype in mammalian brain.
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Affiliation(s)
- C Zocchi
- Schering-Plough Research Institute, San Raffaele Science Park, Milan, Italy
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