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Neri JM, Cavalcanti LN, Araújo RM, Menezes FG. 2,3-Dichloroquinoxaline as a versatile building block for heteroaromatic nucleophilic substitution: A review of the last decade. ARAB J CHEM 2020. [DOI: 10.1016/j.arabjc.2017.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Beswick P, Wahab B, Honey MA, Paradowski M, Jiang K, Lochner M, Murrell-Lagnado RD, Thompson AJ. A challenge finding P2X1 and P2X4 ligands. Neuropharmacology 2019; 157:107674. [PMID: 31238045 DOI: 10.1016/j.neuropharm.2019.107674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/24/2019] [Accepted: 06/17/2019] [Indexed: 01/09/2023]
Abstract
Identifying novel small-molecule P2X1 and P2X4 ligands with sub-type specificity and high-affinity remains a pharmacological challenge. Here we use computational methods, electrophysiology and fluorescent microplate assays to screen for ligand candidates acting at these receptors. Modelling and docking identified 80 compounds for testing at P2X4 receptors, and 20 of these showed >50% inhibition in fluorescence-based assays, making them appealing for further SAR studies. Confirmation of activity by two-electrode voltage clamp, followed by their elaboration resulted in only minor improvements in potency, with the highest IC50 being 295 μM. Testing on P2X1 receptors, resulted in a series of biguanide compounds that yielded a maximum IC50 of 100 μM, but no consistent SAR could be found. Potencies of established antagonists gave expected results, although the measured potencies varied between techniques and no antagonism could be found for compounds such as paroxetine, carbamazepine, 9(10H)-acridanone, acridinol and phenoxazine-type heterocycles. This study highlights the challenge of identifying P2X4 and P2X1 ligands and suggests that a combination of complimentary approaches is needed if we are to be confident of ligand activities at these receptors.
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Affiliation(s)
- Paul Beswick
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Ben Wahab
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Mark A Honey
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | | | - Ke Jiang
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland
| | - Martin Lochner
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland
| | - Ruth D Murrell-Lagnado
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
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Bromination of quinoxaline and derivatives: Effective synthesis of some new brominated quinoxalines. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.02.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Ruepp MD, Brozik JA, de Esch IJP, Farndale RW, Murrell-Lagnado RD, Thompson AJ. A fluorescent approach for identifying P2X1 ligands. Neuropharmacology 2015; 98:13-21. [PMID: 26026951 PMCID: PMC4728187 DOI: 10.1016/j.neuropharm.2015.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/02/2015] [Accepted: 05/12/2015] [Indexed: 02/06/2023]
Abstract
There are no commercially available, small, receptor-specific P2X1 ligands. There are several synthetic derivatives of the natural agonist ATP and some structurally-complex antagonists including compounds such as PPADS, NTP-ATP, suramin and its derivatives (e.g. NF279, NF449). NF449 is the most potent and selective ligand, but potencies of many others are not particularly high and they can also act at other P2X, P2Y and non-purinergic receptors. While there is clearly scope for further work on P2X1 receptor pharmacology, screening can be difficult owing to rapid receptor desensitisation. To reduce desensitisation substitutions can be made within the N-terminus of the P2X1 receptor, but these could also affect ligand properties. An alternative is the use of fluorescent voltage-sensitive dyes that respond to membrane potential changes resulting from channel opening. Here we utilised this approach in conjunction with fragment-based drug-discovery. Using a single concentration (300 μM) we identified 46 novel leads from a library of 1443 fragments (hit rate = 3.2%). These hits were independently validated by measuring concentration-dependence with the same voltage-sensitive dye, and by visualising the competition of hits with an Alexa-647-ATP fluorophore using confocal microscopy; confocal yielded kon (1.142 × 106 M−1 s−1) and koff (0.136 s−1) for Alexa-647-ATP (Kd = 119 nM). The identified hit fragments had promising structural diversity. In summary, the measurement of functional responses using voltage-sensitive dyes was flexible and cost-effective because labelled competitors were not needed, effects were independent of a specific binding site, and both agonist and antagonist actions were probed in a single assay. The method is widely applicable and could be applied to all P2X family members, as well as other voltage-gated and ligand-gated ion channels. This article is part of the Special Issue entitled ‘Fluorescent Tools in Neuropharmacology’. A novel fluorescence-based screening approach for identifying P2X1 receptor ligand candidates. Fragment-based drug discovery applied to ligand-gated ion channels. The use of confocal microscopy to determine the kinetics and affinity of Alexa-647-ATP binding to P2X1 receptors. Alexa-647-ATP for imaging P2X1 receptors on live cells.
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Affiliation(s)
- Marc-David Ruepp
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - James A Brozik
- Washington State University, Department of Chemistry, Pullman, WA 99164-4630, USA
| | - Iwan J P de Esch
- Medicinal Chemistry, VU University Amsterdam, Amsterdam, The Netherlands
| | - Richard W Farndale
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | | | - Andrew J Thompson
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK.
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Schultes S, Kooistra AJ, Vischer HF, Nijmeijer S, Haaksma EEJ, Leurs R, de Esch IJP, de Graaf C. Combinatorial Consensus Scoring for Ligand-Based Virtual Fragment Screening: A Comparative Case Study for Serotonin 5-HT(3)A, Histamine H(1), and Histamine H(4) Receptors. J Chem Inf Model 2015; 55:1030-44. [PMID: 25815783 DOI: 10.1021/ci500694c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In the current study we have evaluated the applicability of ligand-based virtual screening (LBVS) methods for the identification of small fragment-like biologically active molecules using different similarity descriptors and different consensus scoring approaches. For this purpose, we have evaluated the performance of 14 chemical similarity descriptors in retrospective virtual screening studies to discriminate fragment-like ligands of three membrane-bound receptors from fragments that are experimentally determined to have no affinity for these proteins (true inactives). We used a complete fragment affinity data set of experimentally determined ligands and inactives for two G protein-coupled receptors (GPCRs), the histamine H1 receptor (H1R) and the histamine H4 receptor (H4R), and one ligand-gated ion channel (LGIC), the serotonin receptor (5-HT3AR), to validate our retrospective virtual screening studies. We have exhaustively tested consensus scoring strategies that combine the results of multiple actives (group fusion) or combine different similarity descriptors (similarity fusion), and for the first time systematically evaluated different combinations of group fusion and similarity fusion approaches. Our studies show that for these three case study protein targets both consensus scoring approaches can increase virtual screening enrichments compared to single chemical similarity search methods. Our cheminformatics analyses recommend to use a combination of both group fusion and similarity fusion for prospective ligand-based virtual fragment screening.
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Affiliation(s)
- Sabine Schultes
- †Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Albert J Kooistra
- †Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Henry F Vischer
- †Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Saskia Nijmeijer
- †Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Eric E J Haaksma
- †Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Rob Leurs
- †Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Iwan J P de Esch
- †Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Chris de Graaf
- †Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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Ivanova B, Spiteller M. Quinoxalines as potent selective CRFRs ligands for monitoring and brain diagnostic. Bioorg Chem 2014; 58:53-64. [PMID: 25437530 DOI: 10.1016/j.bioorg.2014.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/16/2014] [Accepted: 10/22/2014] [Indexed: 01/15/2023]
Abstract
The paper highlighted quinoxalines as potent ligands to corticotropin-releasing factor receptor types 1 and 2. The content includes design and structure-activity relationship of 50 model substances to CRFR1, CRFR2α and CRF2β, respectively. It is important to bear in mind, that our concept has based on challenging research task, designing for selective CRFRs ligands. Because,: (i) These macromolecules can bond more than one ligand, thus causing for a distinct physiological response; (ii) CRFRs also participate readily in protein-protein interactions; (iii) CRFRs have two step activation mechanism and; (iv) CRFR1 has low selectivity. In spite of, numerous research efforts, which have been devoted to the isolation of series peptidic and non-peptidic CRFRs agonists, the poor penetration across blood-brain barrier restricts, their wide application in the clinical practice. Furthermore, the biological role of CRFR2 is not yet fully understood. For that reason, the studies of the structure-activity relationship have significant impact in the field. The great advantages of quinoxalines as prospective ligands are based on their: (a) One-step synthetic road, using mild experimental conditions and, allowing to involve various functional groups in the molecular scaffold as well as good-to-excellent yields, employing Fischer and Hinsberg methods; (b) High selectivity to CRFRs sub-types and; (c) Tunable fluorescence emission within the frame of a large scale of the electromagnetic spectrum ∈ 500-700 nm.
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Affiliation(s)
- Bojidarka Ivanova
- Lehrstuhl für Analytische Chemie, Institut für Umweltforschung, Fakultät für Chemie, Universität Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Nordrhein-Westfalen, Germany.
| | - Michael Spiteller
- Lehrstuhl für Analytische Chemie, Institut für Umweltforschung, Fakultät für Chemie, Universität Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Nordrhein-Westfalen, Germany
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Present status of quinoxaline motifs: Excellent pathfinders in therapeutic medicine. Eur J Med Chem 2014; 85:688-715. [DOI: 10.1016/j.ejmech.2014.08.034] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 08/07/2014] [Accepted: 08/08/2014] [Indexed: 11/18/2022]
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Thompson AJ, Verheij MHP, Verbeek J, Windhorst AD, de Esch IJP, Lummis SCR. The binding characteristics and orientation of a novel radioligand with distinct properties at 5-HT3A and 5-HT3AB receptors. Neuropharmacology 2014; 86:378-88. [PMID: 25174552 PMCID: PMC4220016 DOI: 10.1016/j.neuropharm.2014.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/22/2014] [Accepted: 08/09/2014] [Indexed: 12/22/2022]
Abstract
VUF10166 (2-chloro-3-(4-methyl piperazin-1-yl)quinoxaline) is a ligand that binds with high affinity to 5-HT3 receptors. Here we synthesise [(3)H]VUF10166 and characterise its binding properties at 5-HT3A and 5-HT3AB receptors. At 5-HT3A receptors [(3)H]VUF10166 displayed saturable binding with a Kd of 0.18 nM. Kinetic measurements gave monophasic association (6.25 × 10(7) M(-1) min(-1)) and dissociation (0.01 min(-1)) rates that yielded a similar Kd value (0.16 nM). At 5-HT3AB receptors two association (6.15 × 10(-7), 7.23 M(-1) min(-1)) and dissociation (0.024, 0.162 min(-1)) rates were seen, yielding Kd values (0.38 nM and 22 nM) that were consistent with values obtained in saturation (Kd = 0.74 nM) and competition (Ki = 37 nM) binding experiments respectively. At both receptor types, specific binding was inhibited by classical 5-HT3 receptor-selective orthosteric ligands (5-HT, allosetron, d-tubocurarine, granisetron, mCPBG, MDL72222, quipazine), but not by non-competitive antagonists (bilobalide, ginkgolide B, picrotoxin) or competitive ligands of other Cys-loop receptors (ACh, bicuculline, glycine, gabazine). To explore VUF10166 ligand-receptor interactions we used in silico modelling and docking, and tested the predictions using site directed mutagenesis. The data suggest that VUF10166 adopts a similar orientation to 5-HT3 receptor agonists bound in AChBP (varenicline) and 5HTBP (5-HT) crystal structures.
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Affiliation(s)
| | - Mark H P Verheij
- Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Joost Verbeek
- VU University Medical Center, Dept Radiology & Nuclear Medicine, Amsterdam, The Netherlands
| | - Albert D Windhorst
- VU University Medical Center, Dept Radiology & Nuclear Medicine, Amsterdam, The Netherlands
| | - Iwan J P de Esch
- Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Sarah C R Lummis
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
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