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Yin X, Vesvoranan O, Andreopoulos F, Dauer EA, Gu W, Huang CYC. Analysis of Extracellular ATP Distribution in the Intervertebral Disc. Ann Biomed Eng 2024; 52:542-555. [PMID: 37934317 DOI: 10.1007/s10439-023-03398-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 10/25/2023] [Indexed: 11/08/2023]
Abstract
Progressive loss of proteoglycans (PGs) is the major biochemical change during intervertebral disc (IVD) degeneration. Adenosine triphosphate (ATP) as the primary energy source is not only critical for cell survival but also serves as a building block in PG synthesis. Extracellular ATP can mediate a variety of physiological functions and was shown to promote extracellular matrix (ECM) production in the IVD. Therefore, the objective of this study was to develop a 3D finite element model to predict extracellular ATP distribution in the IVD and evaluate the impact of degeneration on extracellular ATP distribution. A novel 3D finite element model of the IVD was developed by incorporating experimental measurements of ATP metabolism and ATP-PG binding kinetics into the mechano-electrochemical mixture theory. The new model was validated by experimental data of porcine IVD, and then used to analyze the extracellular distribution of ATP in human IVDs. Extracellular ATP was shown to bind specifically with PGs in IVD ECM. It was found that annulus fibrosus cells hydrolyze ATP faster than that of nucleus pulposus (NP) cells whereas NP cells exhibited a higher ATP release. The distribution of extracellular ATP in a porcine model was consistent with experimental data in our previous study. The predictions from a human IVD model showed a high accumulation of extracellular ATP in the NP region, whereas the extracellular ATP level was reduced with tissue degeneration. This study provides an understanding of extracellular ATP metabolism and its potential biological influences on the IVD via purinergic signaling.
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Affiliation(s)
- Xue Yin
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Oraya Vesvoranan
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Fotios Andreopoulos
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Edward A Dauer
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Weiyong Gu
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL, USA
| | - C-Y Charles Huang
- Department of Biomedical Engineering, College of Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33124-0621, USA.
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Yang H, Micovic N, Monaghan JR, Clark HA. Click Chemistry-Enabled Conjugation Strategy for Producing Dibenzodiazepinone-Type Fluorescent Probes To Target M 2 Acetylcholine Receptors. Bioconjug Chem 2022; 33:2223-2233. [PMID: 36327428 DOI: 10.1021/acs.bioconjchem.2c00446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The development of fluorescently labeled receptor-targeting compounds represents a powerful pharmacological tool to study and characterize ligand-receptor interactions. Despite significant advances in developing sub-type-specific antagonists for muscarinic acetylcholine receptors (mAChRs), reports on antagonists feasible for click chemistry are less common. Here, we designed and synthesized an antagonist suitable for probe attachment through click chemistry, namely, dibenzodiazepinone (DIBA)-alkyne, based on a previously reported DIBA scaffold with a high binding affinity to type-2 mAChR (M2R). To demonstrate the versatility of DIBA-alkyne as a building block for bioconjugates, we assembled DIBA-alkyne with Cyanine5 fluorophores (Cy5) and polyethylene glycol (PEG) biomolecules to obtain fluorescent DIBA antagonist (DIBA-Cy5) and fluorescent DIBA PEG derivatives. Flow cytometric analysis showed that DIBA-Cy5 possessed a high binding affinity to M2R (Kd = 1.80 nM), a two-order magnitude higher binding affinity than M1R. Fluorescent DIBA PEG derivatives maintained a potent binding to the M2R (Kd ≤ 4 nM), confirmed by confocal microscopic imaging. Additionally, DIBA-Cy5 can serve as a fluorescent ligand in the receptor-ligand competitive binding assay for other mAChR ligands, an attractive alternative to the traditional radioligand-based assay. The competitive binding mode between DIBA-Cy5 and orthosteric antagonist atropine/allosteric modulator LY2119620 indicated a dualsteric binding mode of the DIBA-type antagonist to M2R. Lastly, we demonstrated the direct staining of DIBA-Cy5 to M2R receptors in the sinoatrial node of a mouse heart. The adaptability of the clickable DIBA antagonist to a wide range of fluorophores and biomolecules can facilitate its use in various biomedical applications such as binding assays that screen compounds for M2R as the receptor target.
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Affiliation(s)
- Hongrong Yang
- Department of Bioengineering, Northeastern University, Boston, Massachusetts02115, United States
| | - Nicholas Micovic
- Department of Bioengineering, Northeastern University, Boston, Massachusetts02115, United States
| | - James R Monaghan
- Department of Biology, Northeastern University, Boston, Massachusetts02115, United States
- Institute for Chemical Imaging of Living Systems, Northeastern University, Boston, Massachusetts02115, United States
| | - Heather A Clark
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona85281, United States
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Pharmacodynamic model of slow reversible binding and its applications in pharmacokinetic/pharmacodynamic modeling: review and tutorial. J Pharmacokinet Pharmacodyn 2022; 49:493-510. [PMID: 36040645 PMCID: PMC9578295 DOI: 10.1007/s10928-022-09822-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/12/2022] [Indexed: 10/14/2022]
Abstract
Therapeutic responses of most drugs are initiated by the rate and degree of binding to their receptors or targets. The law of mass action describes the rate of drug-receptor complex association (kon) and dissociation (koff) where the ratio koff/kon is the equilibrium dissociation constant (Kd). Drugs with slow reversible binding (SRB) often demonstrate delayed onset and prolonged pharmacodynamic effects. This report reviews evidence for drugs with SRB features, describes previous pharmacokinetic/pharmacodynamic (PK/PD) modeling efforts of several such drugs, provides a tutorial on the mathematics and properties of SRB models, demonstrates applications of SRB models to additional compounds, and compares PK/PD fittings of SRB with other mechanistic models. We identified and summarized 52 drugs with in vitro-confirmed SRB from a PubMed literature search. Simulations with a SRB model and observed PK/PD profiles showed delayed and prolonged responses and that increasing doses/kon or decreasing koff led to greater expected maximum effects and a longer duration of effects. Recession slopes for return of responses to baseline after single doses were nearly linear with an inflection point that approaches a limiting value at larger doses. The SRB model newly captured literature data for the antihypertensive effects of candesartan and antiallergic effects of noberastine. Their PD profiles could also be fitted with indirect response and biophase models with minimal differences. The applicability of SRB models is probably commonplace, but underappreciated, owing to the need for in vitro confirmation of binding kinetics and the similarity of PK/PD profiles to models with other mechanistic determinants.
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Sykes DA, Jain P, Charlton SJ. Investigating the Influence of Tracer Kinetics on Competition-Kinetic Association Binding Assays: Identifying the Optimal Conditions for Assessing the Kinetics of Low-Affinity Compounds. Mol Pharmacol 2019; 96:378-392. [PMID: 31436538 DOI: 10.1124/mol.119.116764] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 06/22/2019] [Indexed: 12/16/2022] Open
Abstract
An increased appreciation of the importance of optimizing drug-binding kinetics has lead to the development of various techniques for measuring the kinetics of unlabeled compounds. One approach is the competition-association kinetic binding method first described in the 1980s. The kinetic characteristics of the tracer employed greatly affects the reliability of estimated kinetic parameters, a barrier to successfully introducing these kinetic assays earlier in the drug discovery process. Using a modeling and Monte Carlo simulation approach, we identify the optimal tracer characteristics for determining the kinetics of the range of unlabeled ligands typically encountered during the different stages of a drug discovery program (i.e., rapidly dissociating, e.g., k off = 10 minute-1 low-affinity "hits" through to slowly dissociating e.g., k off = 0.01 minute-1 high-affinity "candidates"). For more rapidly dissociating ligands (e.g., k off = 10 minute-1), the key to obtaining accurate kinetic parameters was to employ a tracer with a relatively fast off-rate (e.g., k off = 1 minute-1) or, alternatively, to increase the tracer concentration. Reductions in assay start-time ≤1second and read frequency ≤5 seconds significantly improved the reliability of curve fitting. Timing constraints are largely dictated by the method of detection, its inherent sensitivity (e.g., TR-FRET versus radiometric detection), and the ability to inject samples online. Furthermore, we include data from TR-FRET experiments that validate this simulation approach, confirming its practical utility. These insights into the optimal experimental parameters for development of competition-association assays provide a framework for identifying and testing novel tracers necessary for profiling unlabeled competitors, particularly rapidly dissociating low-affinity competitors.
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Affiliation(s)
- David A Sykes
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom (D.A.S., P.J., S.J.C.); Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, United Kingdom (D.A.S., P.J., S.J.C.); and Excellerate Bioscience Ltd, Discovery Building, BioCity, Nottingham, United Kingdom (S.J.C.)
| | - Palash Jain
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom (D.A.S., P.J., S.J.C.); Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, United Kingdom (D.A.S., P.J., S.J.C.); and Excellerate Bioscience Ltd, Discovery Building, BioCity, Nottingham, United Kingdom (S.J.C.)
| | - Steven J Charlton
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom (D.A.S., P.J., S.J.C.); Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, United Kingdom (D.A.S., P.J., S.J.C.); and Excellerate Bioscience Ltd, Discovery Building, BioCity, Nottingham, United Kingdom (S.J.C.)
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Probe dependency in the determination of ligand binding kinetics at a prototypical G protein-coupled receptor. Sci Rep 2019; 9:7906. [PMID: 31133718 PMCID: PMC6536503 DOI: 10.1038/s41598-019-44025-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/25/2019] [Indexed: 01/28/2023] Open
Abstract
Drug-target binding kinetics are suggested to be important parameters for the prediction of in vivo drug-efficacy. For G protein-coupled receptors (GPCRs), the binding kinetics of ligands are typically determined using association binding experiments in competition with radiolabelled probes, followed by analysis with the widely used competitive binding kinetics theory developed by Motulsky and Mahan. Despite this, the influence of the radioligand binding kinetics on the kinetic parameters derived for the ligands tested is often overlooked. To address this, binding rate constants for a series of histamine H1 receptor (H1R) antagonists were determined using radioligands with either slow (low koff) or fast (high koff) dissociation characteristics. A correlation was observed between the probe-specific datasets for the kinetic binding affinities, association rate constants and dissociation rate constants. However, the magnitude and accuracy of the binding rate constant-values was highly dependent on the used radioligand probe. Further analysis using recently developed fluorescent binding methods corroborates the finding that the Motulsky-Mahan methodology is limited by the employed assay conditions. The presented data suggest that kinetic parameters of GPCR ligands depend largely on the characteristics of the probe used and results should therefore be viewed within the experimental context and limitations of the applied methodology.
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Synthesis and biological evaluation of 3-(2-aminoethyl) uracil derivatives as gonadotropin-releasing hormone (GnRH) receptor antagonists. Eur J Med Chem 2018; 145:413-424. [PMID: 29335207 DOI: 10.1016/j.ejmech.2017.12.095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/29/2017] [Accepted: 12/30/2017] [Indexed: 11/23/2022]
Abstract
We investigated a series of uracil analogues by introducing various substituents on the phenyl ring of the N-3 aminoethyl side chain and evaluated their antagonistic activity against human gonadotropin-releasing hormone (GnRH) receptors. Analogues with substituents at the ortho or meta position demonstrated potent in vitro antagonistic activity. Specifically, the introduction of a 2-OMe group enhanced nuclear factor of activated T-cells (NFAT) inhibition up to 6-fold compared to the unsubstituted analogue. We identified compound 12c as a highly potent GnRH antagonist with moderate CYP inhibition. Compound 12c showed potent and prolonged LH suppression after a single dose was orally administered in castrated monkeys compared to a known antagonist, Elagolix. We believe that our SAR study offers useful insights to design GnRH antagonists as a potential treatment option for endometriosis.
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Xia L, de Vries H, Yang X, Lenselink EB, Kyrizaki A, Barth F, Louvel J, Dreyer MK, van der Es D, IJzerman AP, Heitman LH. Kinetics of human cannabinoid 1 (CB1) receptor antagonists: Structure-kinetics relationships (SKR) and implications for insurmountable antagonism. Biochem Pharmacol 2017; 151:166-179. [PMID: 29102677 DOI: 10.1016/j.bcp.2017.10.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/31/2017] [Indexed: 10/18/2022]
Abstract
While equilibrium binding affinities and in vitro functional antagonism of CB1 receptor antagonists have been studied in detail, little is known on the kinetics of their receptor interaction. In this study, we therefore conducted kinetic assays for nine 1-(4,5-diarylthiophene-2-carbonyl)-4-phenylpiperidine-4-carboxamide derivatives and included the CB1 antagonist rimonabant as a comparison. For this we newly developed a dual-point competition association assay with [3H]CP55940 as the radioligand. This assay yielded Kinetic Rate Index (KRI) values from which structure-kinetics relationships (SKR) of hCB1 receptor antagonists could be established. The fast dissociating antagonist 6 had a similar receptor residence time (RT) as rimonabant, i.e. 19 and 14 min, respectively, while the slowest dissociating antagonist (9) had a very long RT of 2222 min, i.e. pseudo-irreversible dissociation kinetics. In functional assays, 9 displayed insurmountable antagonism, while the effects of the shortest RT antagonist 6 and rimonabant were surmountable. Taken together, this study shows that hCB1 receptor antagonists can have very divergent RTs, which are not correlated to their equilibrium affinities. Furthermore, their RTs appear to define their mode of functional antagonism, i.e. surmountable vs. insurmountable. Finally, based on the recently resolved hCB1 receptor crystal structure, we propose that the differences in RT can be explained by a different binding mode of antagonist 9 from short RT antagonists that is able to displace unfavorable water molecules. Taken together, these findings are of importance for future design and evaluation of potent and safe hCB1 receptor antagonists.
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Affiliation(s)
- Lizi Xia
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands
| | - Henk de Vries
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands
| | - Xue Yang
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands
| | - Eelke B Lenselink
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands
| | - Athina Kyrizaki
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands
| | - Francis Barth
- Sanofi-Aventis Research and Development, 371, Rue du Professeur Blayac, 34184 Montpellier Cedex 04, France
| | - Julien Louvel
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands
| | - Matthias K Dreyer
- Sanofi-Aventis Deutschland GmbH R&D, Integrated Drug Discovery, Industriepark Hoechst, 65926 Frankfurt, Germany
| | - Daan van der Es
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands
| | - Adriaan P IJzerman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands
| | - Laura H Heitman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, The Netherlands.
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Lever SZ, Fan KH, Lever JR. Tactics for preclinical validation of receptor-binding radiotracers. Nucl Med Biol 2017; 44:4-30. [PMID: 27755986 PMCID: PMC5161541 DOI: 10.1016/j.nucmedbio.2016.08.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 08/24/2016] [Accepted: 08/24/2016] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Aspects of radiopharmaceutical development are illustrated through preclinical studies of [125I]-(E)-1-(2-(2,3-dihydrobenzofuran-5-yl)ethyl)-4-(iodoallyl)piperazine ([125I]-E-IA-BF-PE-PIPZE), a radioligand for sigma-1 (σ1) receptors, coupled with examples from the recent literature. Findings are compared to those previously observed for [125I]-(E)-1-(2-(2,3-dimethoxy-5-yl)ethyl)-4-(iodoallyl)piperazine ([125I]-E-IA-DM-PE-PIPZE). METHODS Syntheses of E-IA-BF-PE-PIPZE and [125I]-E-IA-BF-PE-PIPZE were accomplished by standard methods. In vitro receptor binding studies and autoradiography were performed, and binding potential was predicted. Measurements of lipophilicity and protein binding were obtained. In vivo studies were conducted in mice to evaluate radioligand stability, as well as specific binding to σ1 sites in brain, brain regions and peripheral organs in the presence and absence of potential blockers. RESULTS E-IA-BF-PE-PIPZE exhibited high affinity and selectivity for σ1 receptors (Ki = 0.43 ± 0.03 nM, σ2/σ1 = 173). [125I]-E-IA-BF-PE-PIPZE was prepared in good yield and purity, with high specific activity. Radioligand binding provided dissociation (koff) and association (kon) rate constants, along with a measured Kd of 0.24 ± 0.01 nM and Bmax of 472 ± 13 fmol/mg protein. The radioligand proved suitable for quantitative autoradiography in vitro using brain sections. Moderate lipophilicity, Log D7.4 2.69 ± 0.28, was determined, and protein binding was 71 ± 0.3%. In vivo, high initial whole brain uptake, >6% injected dose/g, cleared slowly over 24 h. Specific binding represented 75% to 93% of total binding from 15 min to 24 h. Findings were confirmed and extended by regional brain biodistribution. Radiometabolites were not observed in brain (1%). CONCLUSIONS Substitution of dihydrobenzofuranylethyl for dimethoxyphenethyl increased radioligand affinity for σ1 receptors by 16-fold. While high specific binding to σ1 receptors was observed for both radioligands in vivo, [125I]-E-IA-BF-PE-PIPZE displayed much slower clearance kinetics than [125I]-E-IA-DM-PE-PIPZE. Thus, minor structural modifications of σ1 receptor radioligands lead to major differences in binding properties in vitro and in vivo.
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Affiliation(s)
- Susan Z Lever
- Department of Chemistry, University of Missouri, Columbia, MO, USA; University of Missouri Research Reactor Center, Columbia, MO, USA.
| | - Kuo-Hsien Fan
- Department of Chemistry, University of Missouri, Columbia, MO, USA
| | - John R Lever
- Department of Radiology, University of Missouri, Columbia, MO, USA; Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, USA.
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Kim SM, Lee M, Lee SY, Park E, Lee SM, Kim EJ, Han MY, Yoo T, Ann J, Yoon S, Lee J, Lee J. Discovery of an Orally Bioavailable Gonadotropin-Releasing Hormone Receptor Antagonist. J Med Chem 2016; 59:9150-9172. [PMID: 27608177 DOI: 10.1021/acs.jmedchem.6b01071] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We developed a compound library for orally available gonadotropin-releasing hormone (GnRH) receptor antagonists that were based on a uracil scaffold. On the basis of in vitro activity and CYP inhibition profile, we selected 18a (SKI2496) for further in vivo studies. Compound 18a exhibited more selective antagonistic activity toward the human GnRH receptors over the GnRHRs in monkeys and rats, and this compound also showed inhibitory effects on GnRH-mediated signaling pathways. Pharmacokinetic and pharmacodynamic evaluations of 18a revealed improved bioavailability and superior gonadotropic suppression activity compared with Elagolix, the most clinically advanced compound. Considering that 18a exhibited highly potent and selective antagonistic activity toward the hGnRHRs along with favorable pharmacokinetic profiles, we believe that 18a may represent a promising candidate for an orally available hormonal therapy.
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Affiliation(s)
- Seon-Mi Kim
- Life Science R&D Center, SK Chemicals Company Ltd. , Seongnam-si, Gyeonggi-do, 463-400, Korea
| | - Minhee Lee
- Life Science R&D Center, SK Chemicals Company Ltd. , Seongnam-si, Gyeonggi-do, 463-400, Korea
| | - So Young Lee
- Life Science R&D Center, SK Chemicals Company Ltd. , Seongnam-si, Gyeonggi-do, 463-400, Korea
| | - Euisun Park
- Life Science Research Center, Daewoong Pharmaceutical Company Ltd. , Yongin-si, Gyeonggi-do, 449-814, Korea
| | - Soo-Min Lee
- Life Science R&D Center, SK Chemicals Company Ltd. , Seongnam-si, Gyeonggi-do, 463-400, Korea
| | - Eun Jeong Kim
- Life Science R&D Center, SK Chemicals Company Ltd. , Seongnam-si, Gyeonggi-do, 463-400, Korea
| | - Min Young Han
- Life Science R&D Center, SK Chemicals Company Ltd. , Seongnam-si, Gyeonggi-do, 463-400, Korea
| | - Taekyung Yoo
- Life Science R&D Center, SK Chemicals Company Ltd. , Seongnam-si, Gyeonggi-do, 463-400, Korea
| | - Jihyae Ann
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University , Seoul 151-742, Korea
| | - Suyoung Yoon
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University , Seoul 151-742, Korea
| | - Jiyoun Lee
- Department of Global Medical Science, Sungshin University , Seoul 142-732, Korea
| | - Jeewoo Lee
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University , Seoul 151-742, Korea
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Nederpelt I, Bleeker D, Tuijt B, IJzerman AP, Heitman LH. Kinetic binding and activation profiles of endogenous tachykinins targeting the NK1 receptor. Biochem Pharmacol 2016; 118:88-95. [PMID: 27501920 DOI: 10.1016/j.bcp.2016.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 08/02/2016] [Indexed: 02/01/2023]
Abstract
Ligand-receptor binding kinetics (i.e. association and dissociation rates) are emerging as important parameters for drug efficacy in vivo. Awareness of the kinetic behavior of endogenous ligands is pivotal, as drugs often have to compete with those. The binding kinetics of neurokinin 1 (NK1) receptor antagonists have been widely investigated while binding kinetics of endogenous tachykinins have hardly been reported, if at all. Therefore, the aim of this research was to investigate the binding kinetics of endogenous tachykinins and derivatives thereof and their role in the activation of the NK1 receptor. We determined the binding kinetics of seven tachykinins targeting the NK1 receptor. Dissociation rate constants (koff) ranged from 0.026±0.0029min-1 (Sar9,Met(O2)11-SP) to 0.21±0.015min-1 (septide). Association rate constants (kon) were more diverse: substance P (SP) associated the fastest with a kon value of 0.24±0.046nM-1min-1 while neurokinin A (NKA) had the slowest association rate constant of 0.001±0.0002nM-1min-1. Kinetic binding parameters were highly correlated with potency and maximal response values determined in label-free impedance-based experiments on U-251 MG cells. Our research demonstrates large variations in binding kinetics of tachykinins which correlate to receptor activation. These findings provide new insights into the ligand-receptor interactions of tachykinins and underline the importance of measuring binding kinetics of both drug candidates and competing endogenous ligands.
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Affiliation(s)
- I Nederpelt
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - D Bleeker
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - B Tuijt
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - A P IJzerman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - L H Heitman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
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Wei S, Guo H, Gong Z, Zhang F, Ma Z. Triptorelin and cetrorelix induce immune responses and affect uterine development and expressions of genes and proteins of ESR1, LHR, and FSHR of mice. Immunopharmacol Immunotoxicol 2016; 38:197-204. [PMID: 27075695 DOI: 10.3109/08923973.2016.1168432] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT GnRH immunity can reduce the expression of pituitary GnRH levels, and cause the changes in reproductive behaviors. It is unclear whether triptorelin (TRI) and cetrorelix (CET) immunity influences uterine development and expression of follicle-stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR), and estradiol receptor 1 (ERS1) in the uterus. OBJECTIVE The study investigated the effects of active immunity of GnRH agonist and antagonist on uterine development, microstructures, expression of hormone receptors mRNAs, and proteins in uteri. MATERIALS AND METHODS One hundred and five mice were assigned into CET, TRI, and control groups (CG). Mice in CET-1, CET-2, and CET-3 (n = 15) were subcutaneously injected with 10, 20, and 40 μg CET antigens for seven days, respectively. Mice in TRI-1, TRI-2, and TRI-3 were injected with 10, 20, and 40 μg TRI antigens for seven days, respectively. The qPCR and Western blot were implemented to determine expressions of ESR1, LHR and FSHR mRNAs, and proteins. RESULTS Compared with CG, the uterine weights of CET-1, CET-2, and CET-3 increased by 42.86, 62.86, and 10.00% on day 35 (p < 0.05), respectively. Uterine weights of TRI-2, TRI-3 reduced by 28.57% and 11.43% (p < 0.05), respectively. The uterine cavity in CET-1, CET-2, and CET-3 increased; the uterine wall became thick. The cytoplasm of endometrial epithelial cells (EEC) increased slightly. In TRI group, the uterine wall thinned. Uterine cavity became narrow slightly in TRI-1. Numbers of uterine glands reduced. The endometrium epithelial thickness (EET) in CET-1 and CET-2 increased by 68.21% and 79.46% (p < 0.05), respectively. EET in TRI-1 was decreased by 13.69%. Uterine wall thicknesses (UWT) in CET-1 and CET-2 were higher than CG, with the increment of 28.59% and 30.72%. UWT of TRI-1, TRI-2, and TRI-3 reduced by 29.35, 15.36, and 14.41%, respectively. Expressions of ESR1, FSHR, and LHR mRNAs in CET and TRI mice increased. ESR1 and FSHR protein levels increased in all experimental mice (p < 0.05), with a maximum of TRI-3. LHR protein levels of the CET decreased. LHR protein levels of TRI group increased, with a maximum of TRI-3 (p < 0.05). ESR1 protein level had significant negative correlations to mRNA expressions of ESR1, LHR, and FSHR. CONCLUSIONS CET immunity promoted the uterine development, improved EET and UWT, and also promoted the expressions of ESR1 and FSHR protein levels. It lessened the LHR protein levels. TRI immunity blocked EET and UWT, inhibited uterine growth and development. The efficacy of CET immunity was more obvious than TRI.
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Affiliation(s)
- Suocheng Wei
- a Engineering & Technology Research Center of Animal Cells of Gansu Province, Northwest University for Nationalities , Lanzhou , China ;,b Life Science and Engineering College, Northwest University for Nationalities , Lanzhou , China
| | - Huiling Guo
- c Prevention and Control Center for Animal Diseases of Gansu Province , Lanzhou , China
| | - Zhuandi Gong
- d Medicine College, Northwest University for Nationalities , Lanzhou , China
| | - Fengwei Zhang
- b Life Science and Engineering College, Northwest University for Nationalities , Lanzhou , China
| | - Zhongren Ma
- a Engineering & Technology Research Center of Animal Cells of Gansu Province, Northwest University for Nationalities , Lanzhou , China
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12
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Abstract
Radioligand binding assays provide sensitive and quantitative information about guanine nucleotide protein G protein-coupled receptor (GPCR) expression and affinity for a wide variety of ligands, making them essential for drug structure-activity studies and basic GPCR research. Three basic radioligand binding protocols, saturation, indirect (competition, displacement, or modulation), and kinetic binding assays, are used to assess GPCR expression (Bmax), equilibrium dissociation constants for radioligands (Kd) and nonradioactive ligands (Ki), association and dissociation rates, and to distinguish competitive and allosteric mechanisms of GPCR-ligand interactions. Nonspecific radioligand binding may be mitigated by appropriate choices of reaction conditions. Radioligand depletion (bound radioactivity >10% of total radioligand), which compromises accuracy of Kd and Ki measurements, can be limited by adjusting receptor concentration and appropriate radioligand choice. Accurate Kd and Ki values in saturation and indirect binding assays depend on binding equilibrium. Equilibration time for high-affinity ligands, with slow dissociation rates, may require much extended incubation times or increased incubation temperature.
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Affiliation(s)
- Colleen A Flanagan
- School of Physiology and Medical Research Council Receptor Biology Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Wits Parktown, Johannesburg, South Africa.
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13
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Cetrorelix and Triptorelin active immunization influences follicle development and receptor expressions of ovaries in mice. J Appl Biomed 2016. [DOI: 10.1016/j.jab.2015.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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14
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Nederpelt I, Georgi V, Schiele F, Nowak‐Reppel K, Fernández‐Montalván AE, IJzerman AP, Heitman LH. Characterization of 12 GnRH peptide agonists - a kinetic perspective. Br J Pharmacol 2016; 173:128-41. [PMID: 26398856 PMCID: PMC4813373 DOI: 10.1111/bph.13342] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 09/04/2015] [Accepted: 09/09/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Drug-target residence time is an important, yet often overlooked, parameter in drug discovery. Multiple studies have proposed an increased residence time to be beneficial for improved drug efficacy and/or longer duration of action. Currently, there are many drugs on the market targeting the gonadotropin-releasing hormone (GnRH) receptor for the treatment of hormone-dependent diseases. Surprisingly, the kinetic receptor-binding parameters of these analogues have not yet been reported. Therefore, this project focused on determining the receptor-binding kinetics of 12 GnRH peptide agonists, including many marketed drugs. EXPERIMENTAL APPROACH A novel radioligand-binding competition association assay was developed and optimized for the human GnRH receptor with the use of a radiolabelled peptide agonist, [(125) I]-triptorelin. In addition to radioligand-binding studies, a homogeneous time-resolved FRET Tag-lite™ method was developed as an alternative assay for the same purpose. KEY RESULTS Two novel competition association assays were successfully developed and applied to determine the kinetic receptor-binding characteristics of 12 high-affinity GnRH peptide agonists. Results obtained from both methods were highly correlated. Interestingly, the binding kinetics of the peptide agonists were more divergent than their affinities with residence times ranging from 5.6 min (goserelin) to 125 min (deslorelin). CONCLUSIONS AND IMPLICATIONS Our research provides new insights by incorporating kinetic, next to equilibrium, binding parameters in current research and development that can potentially improve future drug discovery targeting the GnRH receptor.
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Affiliation(s)
- Indira Nederpelt
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR)Leiden UniversityLeidenThe Netherlands
| | - Victoria Georgi
- Global Drug Discovery, Lead Discovery BerlinBayer Healthcare PharmaceuticalsBerlinGermany
| | - Felix Schiele
- Global Drug Discovery, Lead Discovery BerlinBayer Healthcare PharmaceuticalsBerlinGermany
| | - Katrin Nowak‐Reppel
- Global Drug Discovery, Lead Discovery BerlinBayer Healthcare PharmaceuticalsBerlinGermany
| | | | - Adriaan P. IJzerman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR)Leiden UniversityLeidenThe Netherlands
| | - Laura H. Heitman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research (LACDR)Leiden UniversityLeidenThe Netherlands
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15
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Guo D, Heitman LH, IJzerman AP. The Role of Target Binding Kinetics in Drug Discovery. ChemMedChem 2015; 10:1793-6. [DOI: 10.1002/cmdc.201500310] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Dong Guo
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research (LACDR); P.O. Box 9502 2300 RA Leiden the Netherlands
| | - Laura H. Heitman
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research (LACDR); P.O. Box 9502 2300 RA Leiden the Netherlands
| | - Adriaan P. IJzerman
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research (LACDR); P.O. Box 9502 2300 RA Leiden the Netherlands
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16
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Guo D, Hillger JM, IJzerman AP, Heitman LH. Drug-Target Residence Time-A Case for G Protein-Coupled Receptors. Med Res Rev 2014; 34:856-92. [DOI: 10.1002/med.21307] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Dong Guo
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research; Leiden University; P.O. Box 9502 2300 RA Leiden the Netherlands
| | - Julia M. Hillger
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research; Leiden University; P.O. Box 9502 2300 RA Leiden the Netherlands
| | - Adriaan P. IJzerman
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research; Leiden University; P.O. Box 9502 2300 RA Leiden the Netherlands
| | - Laura H. Heitman
- Division of Medicinal Chemistry; Leiden Academic Centre for Drug Research; Leiden University; P.O. Box 9502 2300 RA Leiden the Netherlands
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17
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Röblitz S, Stötzel C, Deuflhard P, Jones HM, Azulay DO, van der Graaf PH, Martin SW. A mathematical model of the human menstrual cycle for the administration of GnRH analogues. J Theor Biol 2013. [DOI: 10.1016/j.jtbi.2012.11.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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18
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Hulme EC, Trevethick MA. Ligand binding assays at equilibrium: validation and interpretation. Br J Pharmacol 2011; 161:1219-37. [PMID: 20132208 DOI: 10.1111/j.1476-5381.2009.00604.x] [Citation(s) in RCA: 431] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The focus of this review paper is factors affecting data interpretation in ligand binding assays under equilibrium conditions. Protocols for determining K(d) (the equilibrium dissociation constant) and K(dA) (the equilibrium inhibitor constant) for receptor ligands are discussed. The basic theory describing the interaction of a radiotracer and an unlabelled competitor ligand with a receptor is developed. Inappropriate experimental design may result in ligand depletion and non-attainment of equilibrium, distorting the calculation of K(d) and K(dA) . Strategies, both theoretical and practical, will be given to avoid and correct such errors, thus leading to the determination of reliable values for these constants. In determining K(dA) from competition binding studies, two additional concepts are discussed. First, the necessity to measure an adequate specific binding signal from the bound radiotracer ligand limits the range of affinity constants that can be measured: a particular set of assay conditions may lead to an upper limit on the apparent affinity of unlabelled ligands. Second, an extension of the basic assay methodology can indicate whether the interaction between the tracer and a test ligand is mediated by a competitive or an allosteric mechanism. Finally, the review ends with a discussion of two factors that are often overlooked: buffer composition and the temperature at which the assay is conducted, and the impact these can have on affinity measurements and the understanding of drug interactions.
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Affiliation(s)
- Edward C Hulme
- Division of Physical Biochemistry, MRC National Institute for Medical Research, Mill Hill, London, UK.
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19
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Malany S, Hernandez LM, Smith WF, Crowe PD, Hoare SRJ. Analytical method for simultaneously measuring ex vivo drug receptor occupancy and dissociation rate: application to (R)-dimethindene occupancy of central histamine H1 receptors. J Recept Signal Transduct Res 2009; 29:84-93. [PMID: 19308787 DOI: 10.1080/10799890902721339] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
We introduce a novel experimental method to determine both the extent of ex vivo receptor occupancy of administered compound and its dissociation rate constant (k4). [Here, we reference k4 as the rate of offset of unlabeled ligand in convention with Motulsky and Mahan (1)]. We derived a kinetic rate equation based on the dissociation rate constant for an unlabeled compound competing for the same site as a labeled compound and describe a model to simulate fractional occupancy. To validate our model, we performed in vitro kinetics and ex vivo occupancy experiments in rat cortex with varying concentrations of (R)-dimethindene, a sedating antihistamine. Brain tissue was removed at various times post oral administration, and histamine H1 receptor ligand [3H]-doxepin binding to homogenates from drug-treated or vehicle-treated rats was measured at multiple time points at room temperature. Fractional occupancy and k4 for (R)-dimethindene binding to H1 receptors were calculated by using our proposed model. Rats dosed with 30 and 60 mg/kg (R)-dimethindene showed 42% and 67% occupancy of central H1 receptors, respectively. These results were comparable to occupancy data determined by equilibrium radioligand binding. In addition, drug k4 rate determined by using our ex vivo method was equivalent to k4 determined by in vitro competition kinetics (dissociation half-life t(1/2) approximately 30 min). The outlined method can be used to assess, by simulation and experiment, occupancy for compounds based on dissociation rate constants and contributes to current efforts in drug optimization to profile antagonist efficacy in terms of its kinetic drug-target binding parameters. Data described by the method may be analyzed with commercially available software. Suggested fitting procedures are given in the appendix.
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Affiliation(s)
- Siobhan Malany
- Division of Emerging New Technologies, Neurocrine Biosciences, San Diego, California, USA.
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20
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Chen C, Wu D, Guo Z, Xie Q, Reinhart GJ, Madan A, Wen J, Chen T, Huang CQ, Chen M, Chen Y, Tucci FC, Rowbottom M, Pontillo J, Zhu YF, Wade W, Saunders J, Bozigian H, Struthers RS. Discovery of Sodium R-(+)-4-{2-[5-(2-Fluoro-3-methoxyphenyl)-3-(2-fluoro-6-[trifluoromethyl]benzyl)-4-methyl-2,6-dioxo-3,6-dihydro-2H-pyrimidin-1-yl]-1-phenylethylamino}butyrate (Elagolix), a Potent and Orally Available Nonpeptide Antagonist of the Human Gonadotropin-Releasing Hormone Receptor. J Med Chem 2008; 51:7478-85. [DOI: 10.1021/jm8006454] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chen Chen
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Dongpei Wu
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Zhiqiang Guo
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Qiu Xie
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Greg J. Reinhart
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Ajay Madan
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Jenny Wen
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Takung Chen
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Charles Q. Huang
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Mi Chen
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Yongsheng Chen
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Fabio C. Tucci
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Martin Rowbottom
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Joseph Pontillo
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Yun-Fei Zhu
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Warren Wade
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - John Saunders
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Haig Bozigian
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - R. Scott Struthers
- Department of Medicinal Chemistry, Department of Endocrinology, and Department of Preclinical Development, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
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21
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Lee PH, Miller SC, van Staden C, Cromwell EF. Development of a Homogeneous High-Throughput Live-Cell G-Protein-Coupled Receptor Binding Assay. ACTA ACUST UNITED AC 2008; 13:748-54. [DOI: 10.1177/1087057108317835] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The measurement of ligand receptor binding parameters for G-protein-coupled receptors is indispensable in the drug discovery process. Traditional ligand receptor binding assays require scale-up of cells and membrane preparations, which is an expensive and time-consuming process. In this report, the authors describe the development of a homogeneous live-cell binding assay for GPCRs using a fluorophore-labeled nonpeptide ligand. The model assay used Cy3B-labeled telenzepine and Chinese hamster ovary cells expressing M1 muscarinic acetylcholine receptors. This homogeneous live-cell fluorescence binding assay format is superior to the traditional binding methods because it measures binding of a ligand to intact receptors on living cells. The assay requires no washing or separation steps, thereby allowing a real-time kinetic readout for the determination of ligand association and dissociation from the intact receptors. The results also suggest that miniaturization is feasible without compromising the data quality. ( Journal of Biomolecular Screening 2008:748-754)
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Affiliation(s)
- Paul H. Lee
- Chemistry Research and Discovery, Amgen, Inc., Thousand Oaks, California,
| | | | - Carlo van Staden
- Chemistry Research and Discovery, Amgen, Inc., Thousand Oaks, California
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22
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Chen C, Chen Y, Pontillo J, Guo Z, Huang CQ, Wu D, Madan A, Chen T, Wen J, Xie Q, Tucci FC, Rowbottom M, Zhu YF, Wade W, Saunders J, Bozigian H, Struthers RS. Potent and orally bioavailable zwitterion GnRH antagonists with low CYP3A4 inhibitory activity. Bioorg Med Chem Lett 2008; 18:3301-5. [DOI: 10.1016/j.bmcl.2008.04.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 04/10/2008] [Accepted: 04/11/2008] [Indexed: 10/22/2022]
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23
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Betz SF, Zhu YF, Chen C, Struthers RS. Non-Peptide Gonadotropin-Releasing Hormone Receptor Antagonists. J Med Chem 2008; 51:3331-48. [DOI: 10.1021/jm701249f] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stephen F. Betz
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Yun-Fei Zhu
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - Chen Chen
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
| | - R. Scott Struthers
- Endocrinology & Metabolism, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130
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24
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Tummino PJ, Copeland RA. Residence time of receptor-ligand complexes and its effect on biological function. Biochemistry 2008; 47:5481-92. [PMID: 18412369 DOI: 10.1021/bi8002023] [Citation(s) in RCA: 392] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The formation and duration of binary receptor-ligand complexes are fundamental to many physiologic processes. Most often, the effectiveness of interaction between a receptor and its ligand is quantified in terms of closed system, equilibrium affinity measurements, such as IC50 and Kd. In the context of in vivo biology, however, the extent and duration of responses to receptor-ligand interactions depend greatly on the time period over which the ligand is in residence on its receptor. Here we define receptor-ligand complex residence time in quantitative terms and describe its significance to biological function. Examples of the importance of residence time are presented for natural ligands of different receptor types. The impact of residence time on the optimization of potential ligands as drugs for human medicine is also described.
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Affiliation(s)
- Peter J Tummino
- Department of Enzymology and Mechanistic Pharmacology and Department of Oncology Biology, Oncology Center of Excellence in Drug Discovery, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, USA.
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25
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Chen M, Guo Z, Lanier MC, Zhao L, Betz SF, Huang CQ, Loweth CJ, Ashweek NJ, Liu XJ, Struthers RS, Bradbury MJ, Behan JW, Wen J, O'Brien Z, Saunders J, Zhu YF. Identification of 2-(4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridin-3-yl)-ethylamine derivatives as novel GnRH receptor antagonists. Bioorg Med Chem Lett 2007; 17:3845-50. [PMID: 17521908 DOI: 10.1016/j.bmcl.2007.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 05/03/2007] [Accepted: 05/04/2007] [Indexed: 11/25/2022]
Abstract
A novel series of 2-(4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridin-3-yl)-ethylamine derivatives were designed and synthesized as GnRH receptor antagonists. SAR studies led to a series of highly active molecules against both the rat and human receptors. Furthermore, one potent compound, 17j, demonstrated dose-dependent LH suppression in castrated rats.
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Affiliation(s)
- Mi Chen
- Department of Medicinal Chemistry, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, CA 92130, USA
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26
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Kohout TA, Xie Q, Reijmers S, Finn KJ, Guo Z, Zhu YF, Struthers RS. Trapping of a Nonpeptide Ligand by the Extracellular Domains of the Gonadotropin-Releasing Hormone Receptor Results in Insurmountable Antagonism. Mol Pharmacol 2007; 72:238-47. [PMID: 17409285 DOI: 10.1124/mol.107.035535] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Drugs that exhibit insurmountable antagonism are proposed to provide improved clinical efficacy through extended receptor blockade. Long-term suppression of the gonadotropin-releasing hormone receptor (GnRHR) is an important therapeutic approach for a number of sex hormone-dependent diseases. In this study, we describe the mechanism and structural components required for insurmountable activity of a GnRHR antagonist. TAK-013 behaves as an insurmountable antagonist at the human receptor (hGnRHR) but as a surmountable antagonist at the macaque receptor (mGnRHR). Mutation of the eight residues that differ between hGnRHR and mGnRHR identified Ser-203 and Leu-300 in extracellular loops (ECL) 2 and 3 of hGnRHR as essential for the insurmountability of TAK-013. Substitution of the corresponding residues in mGnRHR with Ser and Leu (mGnRHR-P203S/V300L) converts TAK-013 to an insurmountable antagonist. In addition, mutation of Met-24 to Leu in the amino terminus of hGnRHR also ablates the insurmountable antagonism of TAK-013. The mechanism of insurmountability of TAK-013 was determined to be governed by its rate of dissociation from the receptor. Although the association rates of TAK-013 to hGnRHR, mGnRHR, and mGnRHR-P203S/V300L do not differ, the dissociation rate half-life correlates closely with the degree of insurmountability observed (169, 9, and 55 min, respectively). Taken together, these data suggest a model of the GnRHR in which ECL2, ECL3, and the amino terminus engage with TAK-013 upon its binding to the transmembrane region of the receptor. These additional interactions form a "trap door" above TAK-013, restricting its dissociation and thus resulting in its insurmountability.
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Affiliation(s)
- Trudy A Kohout
- Department of Endocrinology, Neurocrine Biosciences Inc., 12790 El Camino Real, San Diego, CA 92130, USA.
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27
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Struthers RS, Xie Q, Sullivan SK, Reinhart GJ, Kohout TA, Zhu YF, Chen C, Liu XJ, Ling N, Yang W, Maki RA, Bonneville AK, Chen TK, Bozigian HP. Pharmacological characterization of a novel nonpeptide antagonist of the human gonadotropin-releasing hormone receptor, NBI-42902. Endocrinology 2007; 148:857-67. [PMID: 17095587 DOI: 10.1210/en.2006-1213] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Suppression of the hypothalamic-pituitary-gonadal axis by peptides that act at the GnRH receptor has found widespread use in clinical practice for the management of sex-steroid-dependent diseases (such as prostate cancer and endometriosis) and reproductive disorders. Efforts to develop orally available GnRH receptor antagonists have led to the discovery of a novel, potent nonpeptide antagonist, NBI-42902, that suppresses serum LH concentrations in postmenopausal women after oral administration. Here we report the in vitro and in vivo pharmacological characterization of this compound. NBI-42902 is a potent inhibitor of peptide radioligand binding to the human GnRH receptor (K(i) = 0.56 nm). Tritiated NBI-42902 binds with high affinity (K(d) = 0.19 nm) to a single class of binding sites and can be displaced by a range of peptide and nonpeptide GnRH receptor ligands. In vitro experiments demonstrate that NBI-42902 is a potent functional, competitive antagonist of GnRH stimulated IP accumulation, Ca(2+) flux, and ERK1/2 activation. It did not stimulate histamine release from rat peritoneal mast cells. Finally, it is effective in lowering serum LH in castrated male macaques after oral administration. Overall, these data provide a benchmark of pharmacological characteristics required for a nonpeptide GnRH antagonist to effectively suppress gonadotropins in humans and suggest that NBI-42902 may have clinical utility as an oral agent for suppression of the hypothalamic-pituitary-gonadal axis.
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Affiliation(s)
- R Scott Struthers
- Department of Endocrinology, Neurocrine Biosciences Inc., 12790 El Camino Real, San Diego, California 92130, USA.
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28
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Heise CE, Sullivan SK, Crowe PD. Scintillation proximity assay as a high-throughput method to identify slowly dissociating nonpeptide ligand binding to the GnRH receptor. ACTA ACUST UNITED AC 2007; 12:235-9. [PMID: 17208923 DOI: 10.1177/1087057106297362] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Many nonpeptide antagonists of the gonadotropin-releasing hormone (GnRH) receptor, as well as other drug targets, possess a broad range of dissociation kinetic rate constants. Current methods to accurately define kinetic rate parameters such as K(on) and K(off) are time and labor intensive, prompting the development of a screening assay to identify slowly dissociating compounds for follow-up rate constant determination. The authors measured inhibition binding constants (K(i)) for GnRH receptor antagonists after 30 min and 10 h of incubation and observed several compounds with markedly decreased K(i) values over time (Ki(30 min)/Ki(10 h) > 6). They used scintillation proximity assay technology to perform these binding experiments because this homogeneous assay does not have a fixed termination end point as does filtration binding, permitting successive readings to be taken from the same assay plate over an extended period of time. They also used a quantitative method of kinetic rate analysis to confirm that a large disparity between a compound's K(i) value at 30 min and 10 h could identify compounds that dissociate slowly. Thus, the K(i) ratio can be used to screen for and select compounds to test using more quantitative, albeit lower throughput methods to accurately define kinetic rate constants.
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Affiliation(s)
- Christopher E Heise
- Neurocrine Biosciences Inc, Department of Pharmacology, San Diego, CA 92130, USA.
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