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Zhu Y, Su SA, Shen J, Ma H, Le J, Xie Y, Xiang M. Recent advances of the Ephrin and Eph family in cardiovascular development and pathologies. iScience 2024; 27:110556. [PMID: 39188984 PMCID: PMC11345580 DOI: 10.1016/j.isci.2024.110556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/28/2024] Open
Abstract
Erythropoietin-producing hepatoma (Eph) receptors, comprising the largest family of receptor tyrosine kinases (RTKs), exert profound influence on diverse biological processes and pathological conditions such as cancer. Interacting with their corresponding ligands, erythropoietin-producing hepatoma receptor interacting proteins (Ephrins), Eph receptors regulate crucial events like embryonic development, tissue boundary formation, and tumor cell survival. In addition to their well-established roles in embryonic development and cancers, emerging evidence highlights the pivotal contribution of the Ephrin/Eph family to cardiovascular physiology and pathology. Studies have elucidated their involvement in cardiovascular development, atherosclerosis, postnatal angiogenesis, and, more recently, cardiac fibrosis and calcification, suggesting a promising avenue for therapeutic interventions in cardiovascular diseases. There remains a need for a comprehensive synthesis of their collective impact in the cardiovascular context. By exploring the intricate interactions between Eph receptors, ephrins, and cardiovascular system, this review aims to provide a holistic understanding of their roles and therapeutic potential in cardiovascular health and diseases.
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Affiliation(s)
- Yuan Zhu
- Department of Cardiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- State Key Laboratory of Transvascular Implantation Devices, Hangzhou 310009, China
| | - Sheng-an Su
- Department of Cardiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- State Key Laboratory of Transvascular Implantation Devices, Hangzhou 310009, China
| | - Jian Shen
- Department of Cardiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- State Key Laboratory of Transvascular Implantation Devices, Hangzhou 310009, China
| | - Hong Ma
- Department of Cardiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- State Key Laboratory of Transvascular Implantation Devices, Hangzhou 310009, China
| | - Jixie Le
- Department of Cardiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- State Key Laboratory of Transvascular Implantation Devices, Hangzhou 310009, China
| | - Yao Xie
- Department of Cardiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- State Key Laboratory of Transvascular Implantation Devices, Hangzhou 310009, China
| | - Meixiang Xiang
- Department of Cardiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- State Key Laboratory of Transvascular Implantation Devices, Hangzhou 310009, China
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Tennett JC, Epstein SR, Sawyer N. Enhanced EphB2-Specific Peptide Inhibitors through Stabilization of Polyproline II Helical Structure. ACS Chem Biol 2024; 19:1214-1221. [PMID: 38739742 DOI: 10.1021/acschembio.3c00791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Ephrin (Eph) receptors are the largest family of receptor tyrosine kinases. Interactions between Eph receptors and their membrane-bound ephrin protein ligands are associated with many developmental processes as well as various cancers and neurodegenerative diseases. With significant crosstalk between different Eph receptors and ephrin ligands, there is an urgent need for high-affinity ligands that bind specifically to individual Eph receptors to interrogate and modulate their functions. Here, we describe the rational development of potent EphB2 receptor inhibitors derived from the EphB2 receptor-specific SNEW peptide. To improve inhibitory potency, we evaluated 20+ cross-linkers with the goal of spanning and stabilizing a single polyproline II helical turn observed when SNEW binds to the EphB2 receptor. Of the cross-linkers evaluated, an 11-atom cross-linker, composed of a rigid 2,7-dimethylnaphthyl moiety between two cysteine residues, was found to yield the most potent inhibitor. Analysis of the cyclized region of this peptide by NMR and molecular dynamics simulations suggests that cross-linking stabilizes the receptor-bound polyproline II helix structure observed in the receptor-peptide complex. Cross-linked SNEW variants retained binding specificity for EphB2 and showed cross-linker-dependent resistance to trypsin proteolysis. Beyond the discovery of more potent EphB2 receptor inhibitors, these studies illustrate a novel cyclization approach with potential to stabilize polyproline II helical structure in various peptides for specific targeting of the myriad protein-protein interactions (PPIs) mediated by polyproline II helices.
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Affiliation(s)
- Jessica C Tennett
- Department of Chemistry, Fordham University, 441 E. Fordham Rd., Bronx, New York 10458, United States
| | - Sophie R Epstein
- Department of Chemistry, Fordham University, 441 E. Fordham Rd., Bronx, New York 10458, United States
| | - Nicholas Sawyer
- Department of Chemistry, Fordham University, 441 E. Fordham Rd., Bronx, New York 10458, United States
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Eph Receptors in Cancer. Biomedicines 2023; 11:biomedicines11020315. [PMID: 36830852 PMCID: PMC9953285 DOI: 10.3390/biomedicines11020315] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/13/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Eph receptor tyrosine kinases play critical functions during development, in the formation of tissue and organ borders, and the vascular and neural systems. Uniquely among tyrosine kinases, their activities are controlled by binding to membrane-bound ligands, called ephrins. Ephs and ephrins generally have a low expression in adults, functioning mainly in tissue homeostasis and plasticity, but are often overexpressed in cancers, where they are especially associated with undifferentiated or progenitor cells, and with tumour development, vasculature, and invasion. Mutations in Eph receptors also occur in various tumour types and are suspected to promote tumourigenesis. Ephs and ephrins have the capacity to operate as both tumour promoters and tumour suppressors, depending on the circumstances. They have been demonstrated to impact tumour cell proliferation, migration, and invasion in vitro, as well as tumour development, angiogenesis, and metastases in vivo, making them potential therapeutic targets. However, successful development of therapies will require detailed understanding of the opposing roles of Ephs in various cancers. In this review, we discuss the variations in Eph expression and functions in a variety of malignancies. We also describe the multiple strategies that are currently available to target them in tumours, including preclinical and clinical development.
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Batchu S, Joseph Diaz M, Lucke–Wold B. In Silico Binding Analysis of Cannabinoids with Eph Receptors for Therapeutic Use in Gliomas. MEDPRESS PSYCHIATRY AND BEHAVIORAL SCIENCES 2022; 1:mppbs-202209011.. [PMID: 36468933 PMCID: PMC9717618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Background Accumulating evidence suggests overexpression of Eph receptors is associated with malignant human gliomas. Inhibiting interactions of Eph receptors with their ephrin ligands may improve clinical outcomes in glioma patients. The present study investigated the potential of cannabinoids to bind Eph receptors and block Eph/ephrin interactions. Methods Twelve major cannabinoids were computationally docked with ligand binding domains from six glioma-associated Eph receptors through Auto Dock Vina to measure their potential binding affinities. The molecular structures and residue interactions of the most favorable poses for each receptor binding domain were further visually examined. Results Cannabichromene (CBC) exhibited the most favorable binding with EphA2, EphA3, and EphB4 receptor ligand binding domains while tetrahydrocannabinol (THC) was predicted to bind favorably with EphB2 and EphB3 receptor ligand binding domains. EphA4 showed the best potential binding affinity with cannabidivarin (CBDV). Further analysis revealed that these cannabinoids bind to specific locations on Eph receptors required for Eph/ephrin interactions. Conclusion The findings suggest that certain cannabinoids can effectively bind to hydrophobic pockets required for ephrin binding and thereby be used to block subsequent Eph/ephrin interactions.
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Affiliation(s)
| | | | - Brandon Lucke–Wold
- Department of Neurosurgery, University of Florida, Gainesville, FL, United States
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Syringenes A–L: Bioactive dimeric eremophilane sesquiterpenoids from Syringa pinnatifolia. Bioorg Chem 2022; 125:105879. [DOI: 10.1016/j.bioorg.2022.105879] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 03/20/2022] [Accepted: 05/14/2022] [Indexed: 11/20/2022]
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Chen X, Yu D, Zhou H, Zhang X, Hu Y, Zhang R, Gao X, Lin M, Guo T, Zhang K. The role of EphA7 in different tumors. Clin Transl Oncol 2022; 24:1274-1289. [PMID: 35112312 DOI: 10.1007/s12094-022-02783-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/18/2022] [Indexed: 12/06/2022]
Abstract
Ephrin receptor A7 (EphA7) is a member of the Eph receptor family. It is widely involved in signal transduction between cells, regulates cell proliferation and differentiation, and participates in developing neural tubes and brain. In addition, EphA7 also has a dual role of tumor promoter and tumor suppressor. It can participate in cell proliferation, migration and apoptosis through various mechanisms, and affect tumor differentiation, staging and prognosis. EphA7 may be a potential diagnostic marker and tumor treatment target. This article reviews the effects of EphA7 on a variety of tumor biological processes and pathological characteristics, as well as specific effects and regulatory mechanisms.
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Affiliation(s)
- Xiangyi Chen
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
| | - Dechen Yu
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
| | - Haiyu Zhou
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China. .,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China. .,Xigu District People's Hospital, Lanzhou, 730030, China.
| | - Xiaobo Zhang
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
| | - Yicun Hu
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
| | - Ruihao Zhang
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
| | - Xidan Gao
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
| | - Maoqiang Lin
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
| | - Taowen Guo
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
| | - Kun Zhang
- Department of Orthopedics, Lanzhou University Second Hospital, 82 Cuiying Men, Lanzhou, 730030, China.,Gansu Key Laboratory of Bone and Joint Diseases, Lanzhou, 730030, China.,Xigu District People's Hospital, Lanzhou, 730030, China
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Protein-Protein Interaction Inhibitors Targeting the Eph-Ephrin System with a Focus on Amino Acid Conjugates of Bile Acids. Pharmaceuticals (Basel) 2022; 15:ph15020137. [PMID: 35215250 PMCID: PMC8880657 DOI: 10.3390/ph15020137] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 02/05/2023] Open
Abstract
The role of the Eph-ephrin system in the etiology of pathological conditions has been consolidated throughout the years. In this context, approaches directed against this signaling system, intended to modulate its activity, can be strategic therapeutic opportunities. Currently, the most promising class of compounds able to interfere with the Eph receptor-ephrin protein interaction is composed of synthetic derivatives of bile acids. In the present review, we summarize the progresses achieved, in terms of chemical expansions and structure-activity relationships, both in the steroidal core and the terminal carboxylic acid group, along with the pharmacological characterization for the most promising Eph-ephrin antagonists in in vivo settings.
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Kubo H, Yagyu S, Nakamura K, Yamashima K, Tomida A, Kikuchi K, Iehara T, Nakazawa Y, Hosoi H. Development of non-viral, ligand-dependent, EPHB4-specific chimeric antigen receptor T cells for treatment of rhabdomyosarcoma. MOLECULAR THERAPY-ONCOLYTICS 2021; 20:646-658. [PMID: 33816783 PMCID: PMC7985479 DOI: 10.1016/j.omto.2021.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 03/01/2021] [Indexed: 02/06/2023]
Abstract
Ephrin type-B receptor 4 (EPHB4), expressed in tumors including rhabdomyosarcoma, is a suitable target for chimeric antigen receptor (CAR)-T cells. Ligand-independent activation of EPHB4 causes cell proliferation and malignant transformation in rhabdomyosarcoma, whereas ligand-dependent stimulation of EPHB4 induces apoptosis in rhabdomyosarcoma. Therefore, we hypothesized that ligand-based, EPHB4-specific CAR-T cells may kill rhabdomyosarcoma cells without stimulating downstream cell proliferation mechanisms. We developed novel CAR-T cells by targeting EPHB4 via EPHRIN B2, a natural ligand of EPHB4. The generation of EPHB4-CAR-T cells via piggyBac (PB) transposon-based gene transfer resulted in sufficient T cell expansion and CAR positivity (78.5% ± 5.9%). PB-EPHB4-CAR-T cells displayed a dominant stem cell memory fraction (59.4% ± 7.2%) as well as low PD-1 expression (0.60% ± 0.21%) after 14 days of expansion. The PB-EPHB4-CAR-T cells inhibited EPHB4-positive tumor cells without activating cell proliferation downstream of EPHB4, even after multiple tumor re-challenges and suppressed tumor growth in xenograft-bearing mice. Therefore, PB-EPHB4-CAR-T cells possess a memory-rich fraction without early T cell exhaustion and show potential as promising therapeutic agents for treating rhabdomyosarcoma and other EPHB4-positive tumors.
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Affiliation(s)
- Hiroshi Kubo
- Department of Pediatrics, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Shigeki Yagyu
- Department of Pediatrics, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Kayoko Nakamura
- Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kumiko Yamashima
- Department of Pediatrics, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Akimasa Tomida
- Department of Pediatrics, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Ken Kikuchi
- Department of Pediatrics, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Tomoko Iehara
- Department of Pediatrics, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Yozo Nakazawa
- Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan.,Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto, Japan
| | - Hajime Hosoi
- Department of Pediatrics, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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Nandakumar R, Dinu V. Developing a machine learning model to identify protein–protein interaction hotspots to facilitate drug discovery. PeerJ 2020; 8:e10381. [PMID: 33354416 PMCID: PMC7727375 DOI: 10.7717/peerj.10381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 10/27/2020] [Indexed: 02/01/2023] Open
Abstract
Throughout the history of drug discovery, an enzymatic-based approach for identifying new drug molecules has been primarily utilized. Recently, protein–protein interfaces that can be disrupted to identify small molecules that could be viable targets for certain diseases, such as cancer and the human immunodeficiency virus, have been identified. Existing studies computationally identify hotspots on these interfaces, with most models attaining accuracies of ~70%. Many studies do not effectively integrate information relating to amino acid chains and other structural information relating to the complex. Herein, (1) a machine learning model has been created and (2) its ability to integrate multiple features, such as those associated with amino-acid chains, has been evaluated to enhance the ability to predict protein–protein interface hotspots. Virtual drug screening analysis of a set of hotspots determined on the EphB2-ephrinB2 complex has also been performed. The predictive capabilities of this model offer an AUROC of 0.842, sensitivity/recall of 0.833, and specificity of 0.850. Virtual screening of a set of hotspots identified by the machine learning model developed in this study has identified potential medications to treat diseases caused by the overexpression of the EphB2-ephrinB2 complex, including prostate, gastric, colorectal and melanoma cancers which are linked to EphB2 mutations. The efficacy of this model has been demonstrated through its successful ability to predict drug-disease associations previously identified in literature, including cimetidine, idarubicin, pralatrexate for these conditions. In addition, nadolol, a beta blocker, has also been identified in this study to bind to the EphB2-ephrinB2 complex, and the possibility of this drug treating multiple cancers is still relatively unexplored.
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Pretze M, Neuber C, Kinski E, Belter B, Köckerling M, Caflisch A, Steinbach J, Pietzsch J, Mamat C. Synthesis, radiolabelling and initial biological characterisation of 18F-labelled xanthine derivatives for PET imaging of Eph receptors. Org Biomol Chem 2020; 18:3104-3116. [PMID: 32253415 DOI: 10.1039/d0ob00391c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Eph receptor tyrosine kinases, particularly EphA2 and EphB4, represent promising candidates for molecular imaging due to their essential role in cancer progression and therapy resistance. Xanthine derivatives were identified to be potent Eph receptor inhibitors with IC50 values in the low nanomolar range (1-40 nm). These compounds occupy the hydrophobic pocket of the ATP-binding site in the kinase domain. Based on lead compound 1, we designed two fluorine-18-labelled receptor tyrosine kinase inhibitors ([18F]2/3) as potential tracers for positron emission tomography (PET). Docking into the ATP-binding site allowed us to find the best position for radiolabelling. The replacement of the methyl group at the uracil residue ([18F]3) rather than the methyl group of the phenoxy moiety ([18F]2) by a fluoropropyl group was predicted to preserve the affinity of the lead compound 1. Herein, we point out a synthesis route to [18F]2 and [18F]3 and the respective tosylate precursors as well as a labelling procedure to insert fluorine-18. After radiolabelling, both radiotracers were obtained in approximately 5% radiochemical yield with high radiochemical purity (>98%) and a molar activity of >10 GBq μmol-1. In line with the docking studies, first cell experiments revealed specific, time-dependent binding and uptake of [18F]3 to EphA2 and EphB4-overexpressing A375 human melanoma cells, whereas [18F]2 did not accumulate at these cells. Since both tracers [18F]3 and [18F]2 are stable in rat blood, the novel radiotracers might be suitable for in vivo molecular imaging of Eph receptors with PET.
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Affiliation(s)
- Marc Pretze
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany. and Technische Universität Dresden, Fakultät Chemie und Lebensmittelchemie, D-01062 Dresden, Germany
| | - Christin Neuber
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany.
| | - Elisa Kinski
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany.
| | - Birgit Belter
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany.
| | - Martin Köckerling
- Universität Rostock, Institut für Chemie - Anorganische Festkörperchemie, Albert-Einstein-Straße 3a, D-18059 Rostock, Germany
| | - Amedeo Caflisch
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany. and Technische Universität Dresden, Fakultät Chemie und Lebensmittelchemie, D-01062 Dresden, Germany
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany. and Technische Universität Dresden, Fakultät Chemie und Lebensmittelchemie, D-01062 Dresden, Germany
| | - Constantin Mamat
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany. and Technische Universität Dresden, Fakultät Chemie und Lebensmittelchemie, D-01062 Dresden, Germany
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Buckens OJ, El Hassouni B, Giovannetti E, Peters GJ. The role of Eph receptors in cancer and how to target them: novel approaches in cancer treatment. Expert Opin Investig Drugs 2020; 29:567-582. [PMID: 32348169 DOI: 10.1080/13543784.2020.1762566] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Erythropoietin-producing human hepatocellular (Eph) receptors are among the largest family of tyrosine kinases that are divided into two classes: EphA and EphB receptors. Over the past two decades, their role in cancer has become more evident. AREAS COVERED There is a need for new anticancer treatments and more insight in the emerging role of Eph receptors in cancer. Molecular mechanisms underlying the pro-tumorigenic effects of Eph receptors could be exploited for future therapeutic strategies. This review describes the variability in expression levels and different effects on oncogenic and tumor suppressive downstream signaling of Eph receptors in various cancer types, and the small molecules, antibodies and peptides that target these receptors. EXPERT OPINION The complexity of Eph signaling is a challenge for the definition of clear targets for cancer treatment. Nevertheless, numerous drugs that target EphA2 and EphB4 are currently in clinical trials. However, some Eph targeted drugs also inhibit other tyrosine kinases, so it is unclear to what extent the targeting of Eph receptors contributes to their efficacy. Future research is warranted for an improved understanding of the full network in which Eph receptors function. This will be critical for the improvement of the anticancer effects of drugs that target the Eph receptors.
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Affiliation(s)
- Oscar J Buckens
- Amsterdam University College , Amsterdam, The Netherlands.,Laboratory Medical Oncology, Amsterdam UMC Location VUMC, CCA , Amsterdam, The Netherlands
| | - Btissame El Hassouni
- Laboratory Medical Oncology, Amsterdam UMC Location VUMC, CCA , Amsterdam, The Netherlands
| | - Elisa Giovannetti
- Laboratory Medical Oncology, Amsterdam UMC Location VUMC, CCA , Amsterdam, The Netherlands.,Pharmacology Lab, AIRC Start up Unit, Fondazione Pisana per La Scienza , Pisa, Italy
| | - Godefridus J Peters
- Laboratory Medical Oncology, Amsterdam UMC Location VUMC, CCA , Amsterdam, The Netherlands.,Department of Biochemistry, Medical University of Gdansk , Gdansk, Poland
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Mu X, Huang O, Jiang M, Xie Z, Chen D, Zhang X. Prognostic value of ephrin B receptors in breast cancer: An online survival analysis using the microarray data of 3,554 patients. Oncol Lett 2019; 18:742-750. [PMID: 31289549 PMCID: PMC6540016 DOI: 10.3892/ol.2019.10363] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 04/17/2019] [Indexed: 01/19/2023] Open
Abstract
The roles of Ephrin B (EphB) receptors in cancer are relatively unknown as these receptors are associated with complex signaling pathways. A limited number of studies have investigated the association between EphB receptors and prognosis. Using the Kaplan-Meier plotter database, the present study investigated the associations between the mRNA expression levels of five EphB receptors and the outcomes of 3,554 patients with breast cancer who had been followed-up for 20 years. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated to assess the relative risk of survival. The results demonstrated that high mRNA expression levels of EphB2 (HR, 0.74; 95% CI, 0.66-0.84; P=2.1×10-6), EphB4 (HR, 0.82; 95% CI, 0.72-0.93; P=0.0023) and EphB6 (HR, 0.69; 95% CI, 0.61-0.78; P=3×10-9) were significantly associated with improved survival, while a high mRNA expression level of EphB3 (HR, 1.14; 95% CI, 1.01-1.28; P=0.029) was associated with worse survival for patients with breast cancer. High expression levels of all EphB receptors, including EphB1 (HR, 1.4; 95% CI, 1.02-1.94; P=0.039), EphB2 (HR, 1.34; 95% CI, 1.07-1.67; P=0.011), EphB3 (HR, 1.39; 95% CI, 1.11-1.73, P=0.0038), EphB4 (HR, 1.33; 95% CI, 1.06-1.67; P=0.013) and EphB6 (HR, 1.32; 95% CI, 1.05-1.65; P=0.016), were associated with an increased risk of mortality in patients with lymph-node-positive breast cancer. High mRNA expression levels of EphB1 were not associated with survival for all patients with breast cancer (HR, 0.85; 95% CI, 0.72-1.01; P=0.058). The results of the present suggested that EphB receptors may be useful as prognostic biomarkers of breast cancer.
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Affiliation(s)
- Xin Mu
- Department of Urology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian 362000, P.R. China
| | - Ou Huang
- Comprehensive Breast Health Center, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
| | - Min Jiang
- Department of Oncology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215000, P.R. China
| | - Zuoquan Xie
- Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 200025, P.R. China
| | - Debo Chen
- Department of Breast Oncology, The First Hospital of Quanzhou Affiliated to Fujian Medical University, Quanzhou, Fujian 362000, P.R. China
| | - Xi Zhang
- Department of Breast Oncology, The First Hospital of Quanzhou Affiliated to Fujian Medical University, Quanzhou, Fujian 362000, P.R. China
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Arthur A, Nguyen TM, Paton S, Klisuric A, Zannettino ACW, Gronthos S. The osteoprogenitor-specific loss of ephrinB1 results in an osteoporotic phenotype affecting the balance between bone formation and resorption. Sci Rep 2018; 8:12756. [PMID: 30143786 PMCID: PMC6109077 DOI: 10.1038/s41598-018-31190-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 08/14/2018] [Indexed: 01/08/2023] Open
Abstract
The present study investigated the effects of conditional deletion of ephrinB1 in osteoprogenitor cells driven by the Osterix (Osx) promoter, on skeletal integrity in a murine model of ovariectomy-induced (OVX) osteoporosis. Histomorphometric and μCT analyses revealed that loss of ephrinB1 in sham Osx:cre-ephrinB1fl/fl mice caused a reduction in trabecular bone comparable to OVX Osx:Cre mice, which was associated with a significant reduction in bone formation rates and decrease in osteoblast numbers. Interestingly, these observations were not exacerbated in OVX Osx:cre-ephrinB1fl/fl mice. Furthermore, sham Osx:cre-ephrinB1fl/fl mice displayed significantly higher osteoclast numbers and circulating degraded collagen type 1 compared to OVX Osx:Cre mice. Confirmation studies found that cultured monocytes expressing EphB2 formed fewer TRAP+ multinucleated osteoclasts and exhibited lower resorption activity in the presence of soluble ephrinB1-Fc compared to IgG control. This inhibition of osteoclast formation and function induced by ephrinB1-Fc was reversed in the presence of an EphB2 chemical inhibitor. Collectively, these observations suggest that ephrinB1, expressed by osteoprogenitors, influences bone loss during the development of osteoporosis, by regulating both osteoblast and osteoclast formation and function, leading to a loss of skeletal integrity.
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Affiliation(s)
- Agnieszka Arthur
- Mesenchymal Stem Cell Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, 5005, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, 5000, SA, Australia
| | - Thao M Nguyen
- Mesenchymal Stem Cell Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, 5005, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, 5000, SA, Australia
| | - Sharon Paton
- Mesenchymal Stem Cell Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, 5005, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, 5000, SA, Australia.,Myeloma Research Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, 5005, SA, Australia
| | - Ana Klisuric
- Mesenchymal Stem Cell Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, 5005, SA, Australia
| | - Andrew C W Zannettino
- South Australian Health and Medical Research Institute, Adelaide, 5000, SA, Australia.,Myeloma Research Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, 5005, SA, Australia
| | - Stan Gronthos
- Mesenchymal Stem Cell Laboratory, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, 5005, SA, Australia. .,South Australian Health and Medical Research Institute, Adelaide, 5000, SA, Australia.
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14
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Heng BC, Gong T, Xu J, Lim LW, Zhang C. EphrinB2 signalling modulates the neural differentiation of human dental pulp stem cells. Biomed Rep 2018; 9:161-168. [PMID: 29963307 DOI: 10.3892/br.2018.1108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/04/2018] [Indexed: 01/09/2023] Open
Abstract
Dental pulp stem cells (DPSCs) originate from the embryonic neural crest and have neurogenic potential. The present study investigated the roles of the forward and reverse EphrinB2 signalling pathways during DPSC neurogenesis. Treatment of DPSCs with recombinant EphrinB2-Fc protein over 7 days in a neural induction culture resulted in significant downregulation of the following neural markers: βIII-Tubulin, neural cell adhesion molecule (NCAM), nestin, neurogenin 2 (NGN2), neurofilament medium polypeptide and Musashi1. Immunocytochemistry revealed that EphrinB2-Fc-treated DPSCs exhibited more rounded morphologies with fewer neurite outgrowths as well as reduced protein expression of βIII-tubulin and NGN2. Treatment of DPSCs with a peptide inhibitor specific to the EphB4 receptor significantly upregulated expression of the neural markers microtubule-associated protein 2, Musashi1, NGN2 and neuron-specific enolase, whereas treatment with a peptide inhibitor specific to the EphB2 receptor exerted negligible effects on neurogenesis. Transgenic expression of EphrinB2 in DPSCs resulted in significant upregulation of Musashi1 and NCAM gene expression, while treatment of DPSCs with recombinant EphB4-Fc protein led to significant upregulation of only Musashi1. Thus, it may be concluded that stimulation of forward EphrinB2-EphB4 signalling markedly inhibited neurogenesis in DPSCs, whereas suppression of this forward signalling pathway with peptide inhibitor specific to EphB4 promoted neurogenesis. Meanwhile, stimulation of reverse EphB4-EphrinB2 signalling only marginally enhanced the neural differentiation of DPSCs. The present findings indicate the potential application of peptide or small molecule inhibitors of EphrinB2 forward signalling in neural tissue engineering with DPSCs.
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Affiliation(s)
- Boon Chin Heng
- Discipline of Endodontology, Faculty of Dentistry, The Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong, SAR, P.R. China.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong 518057, P.R. China.,Faculty of Science and Technology, Sunway University, Selangor Darul Ehsan 47500, Malaysia
| | - Ting Gong
- Discipline of Endodontology, Faculty of Dentistry, The Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong, SAR, P.R. China.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong 518057, P.R. China
| | - Jianguang Xu
- Discipline of Endodontology, Faculty of Dentistry, The Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong, SAR, P.R. China.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong 518057, P.R. China
| | - Lee Wei Lim
- Faculty of Science and Technology, Sunway University, Selangor Darul Ehsan 47500, Malaysia.,School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, P.R. China
| | - Chengfei Zhang
- Discipline of Endodontology, Faculty of Dentistry, The Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong, SAR, P.R. China.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong 518057, P.R. China
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15
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Chen Y, Zhang H, Zhang Y. Targeting receptor tyrosine kinase EphB4 in cancer therapy. Semin Cancer Biol 2017; 56:37-46. [PMID: 28993206 DOI: 10.1016/j.semcancer.2017.10.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/13/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Eph receptors and their Eph receptor-interacting (ephrin) ligands together form an important cell communication system with diverse roles. Experimental evidence demonstrated Eph receptor bidirectional signaling with both tumor-suppressing and tumor-promoting activities in cancer cells. The tyrosine kinase EphB4, a member of the Eph receptor family, has been associated with tumor angiogenesis, growth and metastasis, thus making it a valuable and attractive target for drug design for therapeutic applications. In the past decade, many studies have focused on elucidating the structure and function of EphB4 in complex with its ligand ephrinB2 for their role in carcinogenesis. Meanwhile, an array of compounds targeting EphB4 have been studied and several selective inhibitors have been tested in clinical studies. This review discusses the structure and function of the EphB4 receptor, analyzes its potential as a target for anticancer therapy, and summarizes the information about inhibitors of EphB4 kinase activity. Conclusively, EphB4 is a challenging but promising therapeutic target in cancer.
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Affiliation(s)
- Yinnan Chen
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Hongmei Zhang
- Department of Endocrinology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, PR China.
| | - Yanmin Zhang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, No. 76, Yanta West Street, #54, Xi'an, Shaanxi Province 710061, PR China.
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16
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Wiemer J, Steinbach J, Pietzsch J, Mamat C. Preparation of a novel radiotracer targeting the EphB4 receptor via radiofluorination using spiro azetidinium salts as precursor. J Labelled Comp Radiopharm 2017; 60:489-498. [DOI: 10.1002/jlcr.3526] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/10/2017] [Accepted: 05/29/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Jens Wiemer
- Institut für Radiopharmazeutische Krebsforschung; Helmholtz-Zentrum Dresden-Rossendorf; Dresden Germany
| | - Jörg Steinbach
- Institut für Radiopharmazeutische Krebsforschung; Helmholtz-Zentrum Dresden-Rossendorf; Dresden Germany
- Fachbereich Chemie und Lebensmittelchemie; Technische Universität Dresden; Dresden Germany
| | - Jens Pietzsch
- Institut für Radiopharmazeutische Krebsforschung; Helmholtz-Zentrum Dresden-Rossendorf; Dresden Germany
- Fachbereich Chemie und Lebensmittelchemie; Technische Universität Dresden; Dresden Germany
| | - Constantin Mamat
- Institut für Radiopharmazeutische Krebsforschung; Helmholtz-Zentrum Dresden-Rossendorf; Dresden Germany
- Fachbereich Chemie und Lebensmittelchemie; Technische Universität Dresden; Dresden Germany
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17
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Ebert K, Wiemer J, Caballero J, Köckerling M, Steinbach J, Pietzsch J, Mamat C. Development of indazolylpyrimidine derivatives as high-affine EphB4 receptor ligands and potential PET radiotracers. Bioorg Med Chem 2015; 23:6025-35. [PMID: 26189032 DOI: 10.1016/j.bmc.2015.06.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 01/06/2023]
Abstract
Due to their essential role in the pathogenesis of cancer, members of the Eph (erythropoietin-producing hepatoma cell line-A2) receptor tyrosine kinase family represent promising candidates for molecular imaging. Thus, the development and preparation of novel radiotracers for the noninvasive imaging of the EphB4 receptor via positron emission tomography (PET) is described. First in silico investigations with the indazolylpyrimidine lead compound which is known to be highly affine to EphB4 were executed to identify favorable labeling positions for an introduction of fluorine-18 to retain the affinity. Based on this, reference compounds as well as precursors were developed and labeled with carbon-11 and fluorine-18, respectively. For this purpose, a protecting group strategy essentially had to be generated to prevent unwanted methylation and to enable the introduction of fluorine-18. Further, a convenient radiolabeling strategy using [(11)C]methyl iodide was established which afforded the isotopically labeled radiotracer in 30-35% RCY (d.c.) which is identical with the original inhibitor molecule. A spiro ammonium precursor was prepared for radiolabeling with fluorine-18. Unfortunately, the labeling did not lead to the desired (18)F-radiotracer under the chosen conditions.
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Affiliation(s)
- Kristin Ebert
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany
| | - Jens Wiemer
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany
| | - Julio Caballero
- Universidad de Talca, Centro de Bioinformática y Simulación Molecular, 2 Norte 685, Casilla 721, Talca, Chile
| | - Martin Köckerling
- Universität Rostock, Institut für Chemie, Anorganische Festkörperchemie, Albert-Einstein-Straße 3a, D-18057 Rostock, Germany
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany; TU Dresden, Fachbereich Chemie und Lebensmittelchemie, D-01062 Dresden, Germany
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany; TU Dresden, Fachbereich Chemie und Lebensmittelchemie, D-01062 Dresden, Germany
| | - Constantin Mamat
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany; TU Dresden, Fachbereich Chemie und Lebensmittelchemie, D-01062 Dresden, Germany.
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18
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Hashimoto W, Ochiai A, Hong CS, Murata K, Chakrabarty AM. Structural studies on Laz, a promiscuous anticancer Neisserial protein. Bioengineered 2015; 6:141-8. [PMID: 25714335 DOI: 10.1080/21655979.2015.1022303] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Azurin and Laz (lipidated azurin) are 2 bacterial proteins with anticancer, anti-viral and anti-parasitic activities. Azurin, isolated from the bacterium Pseudomonas aeruginosa, termed Paz, demonstrates anticancer activity against a range of cancers but not against brain tumors. In contrast, Laz is produced by members of Gonococci/Meningococci, including Neisseria meningitides which can cross the blood-brain barrier to infect brain meninges. It has been previously reported that Laz has an additional 39 amino acid moiety, called an H.8 epitope, in the N-terminal part of the azurin moiety that allows Laz to cross the entry barrier to brain tumors such as glioblastomas. Exactly, how the H.8 epitope helps the azurin moiety of Laz to cross the entry barriers to attack glioblastoma cells is unknown. In this paper, we describe the structural features of the H.8 moiety in Laz using X-ray crystallography and demonstrate that while the azurin moiety of Laz adopts a β-sandwich fold with 2 β-sheets arranged in the Greek key motif, the H.8 epitope was present as a disordered structure outside the Greek key motif. Structures of Paz and H.8 epitope-deficient Laz are well superimposed. The structural flexibility of the H.8 motif in Laz explains the extracellular location of Laz in Neisseria where it can bind the key components of brain tumor cells to disrupt their tight junctions and allow entry of Laz inside the tumors to exert cytotoxicity.
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Affiliation(s)
- Wataru Hashimoto
- a Laboratory of Basic and Applied Molecular Biotechnology; Graduate School of Agriculture ; Kyoto University ; Uji , Kyoto , Japan
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19
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Riedl SJ, Pasquale EB. Targeting the Eph System with Peptides and Peptide Conjugates. Curr Drug Targets 2015; 16:1031-47. [PMID: 26212263 PMCID: PMC4861043 DOI: 10.2174/1389450116666150727115934] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/02/2015] [Accepted: 07/20/2015] [Indexed: 01/06/2023]
Abstract
Eph receptor tyrosine kinases and ephrin ligands constitute an important cell communication system that controls development, tissue homeostasis and many pathological processes. Various Eph receptors/ephrins are present in essentially all cell types and their expression is often dysregulated by injury and disease. Thus, the 14 Eph receptors are attracting increasing attention as a major class of potential drug targets. In particular, agents that bind to the extracellular ephrin-binding pocket of these receptors show promise for medical applications. This pocket comprises a broad and shallow groove surrounded by several flexible loops, which makes peptides particularly suitable to target it with high affinity and selectivity. Accordingly, a number of peptides that bind to Eph receptors with micromolar affinity have been identified using phage display and other approaches. These peptides are generally antagonists that inhibit ephrin binding and Eph receptor/ ephrin signaling, but some are agonists mimicking ephrin-induced Eph receptor activation. Importantly, some of the peptides are exquisitely selective for single Eph receptors. Most identified peptides are linear, but recently the considerable advantages of cyclic scaffolds have been recognized, particularly in light of potential optimization towards drug leads. To date, peptide improvements have yielded derivatives with low nanomolar Eph receptor binding affinity, high resistance to plasma proteases and/or long in vivo half-life, exemplifying the merits of peptides for Eph receptor targeting. Besides their modulation of Eph receptor/ephrin function, peptides can also serve to deliver conjugated imaging and therapeutic agents or various types of nanoparticles to tumors and other diseased tissues presenting target Eph receptors.
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Affiliation(s)
| | - Elena B Pasquale
- Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd., La Jolla, CA 92037, USA.
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20
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Ma B, Kolb S, Diprima M, Karna M, Tosato G, Yang Q, Huang Q, Nussinov R. Investigation of the interactions between the EphB2 receptor and SNEW peptide variants. Growth Factors 2014; 32:236-46. [PMID: 25410963 PMCID: PMC4627370 DOI: 10.3109/08977194.2014.985786] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
EphB2 interacts with cell surface-bound ephrin ligands to relay bidirectional signals. Overexpression of the EphB2 receptor protein has been linked to different types of cancer. The SNEW (SNEWIQPRLPQH) peptide binds with high selectivity and moderate affinity to EphB2, inhibiting Eph-ephrin interactions by competing with ephrin ligands for the EphB2 high-affinity pocket. We used rigorous free energy perturbation (FEP) calculations to re-evaluate the binding interactions of SNEW peptide with the EphB2 receptor, followed by experimental testing of the computational results. Our results provide insight into dynamic interactions of EphB2 with SNEW peptide. While the first four residues of the SNEW peptide are already highly optimized, change of the C-terminal end of the peptide has the potential to improve SNEW-binding affinity. We identified a PXSPY motif that can be similarly aligned with several other EphB2-binding peptides.
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Affiliation(s)
- Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Stephanie Kolb
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Michael Diprima
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Molleshree Karna
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Giovanna Tosato
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Qiqi Yang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Qiang Huang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA
- Sackler Inst. of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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21
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Barton WA, Dalton AC, Seegar TCM, Himanen JP, Nikolov DB. Tie2 and Eph receptor tyrosine kinase activation and signaling. Cold Spring Harb Perspect Biol 2014; 6:cshperspect.a009142. [PMID: 24478383 DOI: 10.1101/cshperspect.a009142] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The Eph and Tie cell surface receptors mediate a variety of signaling events during development and in the adult organism. As other receptor tyrosine kinases, they are activated on binding of extracellular ligands and their catalytic activity is tightly regulated on multiple levels. The Eph and Tie receptors display some unique characteristics, including the requirement of ligand-induced receptor clustering for efficient signaling. Interestingly, both Ephs and Ties can mediate different, even opposite, biological effects depending on the specific ligand eliciting the response and on the cellular context. Here we discuss the structural features of these receptors, their interactions with various ligands, as well as functional implications for downstream signaling initiation. The Eph/ephrin structures are already well reviewed and we only provide a brief overview on the initial binding events. We go into more detail discussing the Tie-angiopoietin structures and recognition.
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Affiliation(s)
- William A Barton
- Department of Biochemistry and Molecular Biology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
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22
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Ma B, Nussinov R. Druggable orthosteric and allosteric hot spots to target protein-protein interactions. Curr Pharm Des 2014; 20:1293-301. [PMID: 23713780 PMCID: PMC6361532 DOI: 10.2174/13816128113199990073] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/21/2013] [Indexed: 11/22/2022]
Abstract
Drug designing targeting protein-protein interactions is challenging. Because structural elucidation and computational analysis have revealed the importance of hot spot residues in stabilizing these interactions, there have been on-going efforts to develop drugs which bind the hot spots and out-compete the native protein partners. The question arises as to what are the key 'druggable' properties of hot spots in protein-protein interactions and whether these mimic the general hot spot definition. Identification of orthosteric (at the protein- protein interaction site) and allosteric (elsewhere) druggable hot spots is expected to help in discovering compounds that can more effectively modulate protein-protein interactions. For example, are there any other significant features beyond their location in pockets in the interface? The interactions of protein-protein hot spots are coupled with conformational dynamics of protein complexes. Currently increasing efforts focus on the allosteric drug discovery. Allosteric drugs bind away from the native binding site and can modulate the native interactions. We propose that identification of allosteric hot spots could similarly help in more effective allosteric drug discovery. While detection of allosteric hot spots is challenging, targeting drugs to these residues has the potential of greatly increasing the hot spot and protein druggability.
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Affiliation(s)
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, NCIFrederick, Frederick, MD 21702.
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23
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Nguyen TM, Arthur A, Hayball JD, Gronthos S. EphB and Ephrin-B interactions mediate human mesenchymal stem cell suppression of activated T-cells. Stem Cells Dev 2013; 22:2751-64. [PMID: 23711177 PMCID: PMC3787464 DOI: 10.1089/scd.2012.0676] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 05/27/2013] [Indexed: 01/13/2023] Open
Abstract
Mesenchymal stromal/stem cells (MSC) express the contact-dependent erythropoietin-producing hepatocellular (Eph) receptor tyrosine kinase family and their cognate ephrin ligands, which are known to regulate thymocyte maturation and selection, T-cell transendothelial migration, activation, co-stimulation, and proliferation. However, the contribution of Eph/ephrin molecules in mediating human MSC suppression of activated T-cells remains to be determined. In the present study, we showed that EphB2 and ephrin-B2 are expressed by ex vivo expanded MSC, while the corresponding ligands, ephrin-B1 and EphB4, respectively, are highly expressed by T-cells. Initial studies demonstrated that EphB2-Fc and ephrin-B2-Fc molecules suppressed T-cell proliferation in allogeneic mixed lymphocyte reaction (MLR) assays compared with human IgG-treated controls. While the addition of a third-party MSC population demonstrated dramatic suppression of T-cell proliferation responses in the MLR, blocking the function of EphB2 or EphB4 receptors using inhibitor binding peptides significantly increased T-cell proliferation. Consistent with these observations, shRNA EphB2 or ephrin-B2 knockdown expression in MSC reduced their ability to inhibit T-cell proliferation. Importantly, the expression of immunosuppressive factors, indoleamine 2, 3-dioxygenase, transforming growth factor-β1, and inducible nitric oxide synthase expressed by MSC, was up-regulated after stimulation with EphB4 and ephrin-B1 in the presence of interferon (IFN)-γ, compared with untreated controls. Conversely, key factors involved in T-cell activation and proliferation, such as interleukin (IL)-2, IFN-γ, tumor necrosis factor-α, and IL-17, were down-regulated by T-cells treated with EphB2 or ephrin-B2 compared with untreated controls. Studies utilizing signaling inhibitors revealed that inhibition of T-cell proliferation is partly mediated through EphB2-induced ephrin-B1 reverse signaling or ephrin-B2-mediated EphB4 forward signaling by activating Src, PI3Kinase, Abl, and JNK kinase pathways, activated by tyrosine phosphorylation. Taken together, these observations suggest that EphB/ephrin-B interactions play an important role in mediating human MSC inhibition of activated T cells.
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MESH Headings
- Cell Proliferation
- Coculture Techniques
- Ephrin-B2/antagonists & inhibitors
- Ephrin-B2/genetics
- Ephrin-B2/metabolism
- Gene Expression Regulation
- Humans
- Indoleamine-Pyrrole 2,3,-Dioxygenase/genetics
- Indoleamine-Pyrrole 2,3,-Dioxygenase/metabolism
- Interferon-gamma/metabolism
- Interferon-gamma/pharmacology
- Interleukin-17/genetics
- Interleukin-17/metabolism
- Interleukin-2/genetics
- Interleukin-2/metabolism
- Lymphocyte Activation
- Lymphocyte Culture Test, Mixed
- Mesenchymal Stem Cells/cytology
- Mesenchymal Stem Cells/drug effects
- Mesenchymal Stem Cells/metabolism
- Nitric Oxide Synthase Type II/genetics
- Nitric Oxide Synthase Type II/metabolism
- Phosphorylation
- Primary Cell Culture
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Receptor, EphB2/antagonists & inhibitors
- Receptor, EphB2/genetics
- Receptor, EphB2/metabolism
- Receptor, EphB4/genetics
- Receptor, EphB4/metabolism
- Signal Transduction
- T-Lymphocytes/cytology
- T-Lymphocytes/drug effects
- T-Lymphocytes/metabolism
- Transforming Growth Factor beta1/genetics
- Transforming Growth Factor beta1/metabolism
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Affiliation(s)
- Thao M. Nguyen
- Mesenchymal Stem Cell Laboratory, School of Medical Sciences, Faculty of Health Sciences, University of Adelaide, Adelaide, SA, Australia
- School of Pharmacy and Medical Sciences and Sansom Institute, University of South Australia, Adelaide, SA, Australia
| | - Agnes Arthur
- Mesenchymal Stem Cell Laboratory, School of Medical Sciences, Faculty of Health Sciences, University of Adelaide, Adelaide, SA, Australia
| | - John D. Hayball
- School of Pharmacy and Medical Sciences and Sansom Institute, University of South Australia, Adelaide, SA, Australia
| | - Stan Gronthos
- Mesenchymal Stem Cell Laboratory, School of Medical Sciences, Faculty of Health Sciences, University of Adelaide, Adelaide, SA, Australia
- Centre for Stem Cell Research and Robinson Institute, School of Medical Sciences, University of Adelaide, Adelaide, SA, Australia
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24
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Huan X, Shi J, Lim L, Mitra S, Zhu W, Qin H, Pasquale EB, Song J. Unique structure and dynamics of the EphA5 ligand binding domain mediate its binding specificity as revealed by X-ray crystallography, NMR and MD simulations. PLoS One 2013; 8:e74040. [PMID: 24086308 PMCID: PMC3782497 DOI: 10.1371/journal.pone.0074040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/25/2013] [Indexed: 12/26/2022] Open
Abstract
The 16 EphA and EphB receptors represent the largest family of receptor tyrosine kinases, and their interactions with 9 ephrin-A and ephrin-B ligands initiate bidirectional signals controlling many physiological and pathological processes. Most interactions occur between receptor and ephrins of the same class, and only EphA4 can bind all A and B ephrins. To understand the structural and dynamic principles that enable Eph receptors to utilize the same jellyroll β-sandwich fold to bind ephrins, the VAPB-MSP domain, peptides and small molecules, we have used crystallography, NMR and molecular dynamics (MD) simulations to determine the first structure and dynamics of the EphA5 ligand-binding domain (LBD), which only binds ephrin-A ligands. Unexpectedly, despite being unbound, the high affinity ephrin-binding pocket of EphA5 resembles that of other Eph receptors bound to ephrins, with a helical conformation over the J–K loop and an open pocket. The openness of the pocket is further supported by NMR hydrogen/deuterium exchange data and MD simulations. Additionally, the EphA5 LBD undergoes significant picosecond-nanosecond conformational exchanges over the loops, as revealed by NMR and MD simulations, but lacks global conformational exchanges on the microsecond-millisecond time scale. This is markedly different from the EphA4 LBD, which shares 74% sequence identity and 87% homology. Consequently, the unbound EphA5 LBD appears to comprise an ensemble of open conformations that have only small variations over the loops and appear ready to bind ephrin-A ligands. These findings show how two proteins with high sequence homology and structural similarity are still able to achieve distinctive binding specificities through different dynamics, which may represent a general mechanism whereby the same protein fold can serve for different functions. Our findings also suggest that a promising strategy to design agonists/antagonists with high affinity and selectivity might be to target specific dynamic states of the Eph receptor LBDs.
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Affiliation(s)
- Xuelu Huan
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Republic of Singapore
| | - Jiahai Shi
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Republic of Singapore
| | - Liangzhong Lim
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Republic of Singapore
| | - Sayantan Mitra
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Wanlong Zhu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Republic of Singapore
| | - Haina Qin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Republic of Singapore
| | - Elena B. Pasquale
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- Pathology Department, University of California San Diego, La Jolla, California, United States of America
| | - Jianxing Song
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Republic of Singapore
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Republic of Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
- * E-mail:
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Automated preparation of [18F]AFP and [18F]BFP: Two novel bifunctional 18F-labeling building blocks for Huisgen-click. J Fluor Chem 2013. [DOI: 10.1016/j.jfluchem.2013.02.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Pretze M, Kuchar M, Bergmann R, Steinbach J, Pietzsch J, Mamat C. An efficient bioorthogonal strategy using CuAAC click chemistry for radiofluorinations of SNEW peptides and the role of copper depletion. ChemMedChem 2013; 8:935-45. [PMID: 23559494 DOI: 10.1002/cmdc.201300053] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Indexed: 12/20/2022]
Abstract
The EphB2 receptor is known to be overexpressed in various types of cancer and is therefore a promising target for tumor cell imaging by positron emission tomography (PET). In this regard, imaging could facilitate the early detection of EphB2-overexpressing tumors, monitoring responses to therapy directed toward EphB2, and thus improvement in patient outcomes. We report the synthesis and evaluation of several fluorine-18-labeled peptides containing the SNEW amino acid motif, with high affinity for the EphB2 receptor, for their potential as radiotracers in the non-invasive imaging of cancer using PET. For the purposes of radiofluorination, EphB2-antagonistic SNEW peptides were varied at the C terminus by the introduction of L-cysteine, and further by alkyne- or azide-modified amino acids. In addition, two novel bifunctional and bioorthogonal labeling building blocks [(18)F]AFP and [(18)F]BFP were applied, and their capacity to introduce fluorine-18 was compared with that of the established building block [(18)F]FBAM. Copper-assisted Huisgen 1,3-dipolar cycloaddition, which belongs to the set of bioorthogonal click chemistry reactions, was used to introduce both novel building blocks into azide- or alkyne-modified SNEW peptides under mild conditions. Finally, the depletion of copper immediately after radiolabeling is a highly important step of this novel methodology.
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Affiliation(s)
- Marc Pretze
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
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Site-selective radiolabeling of peptides by (18)F-fluorobenzoylation with [(18F)]SFB in solution and on solid phase: a comparative study. Amino Acids 2013; 43:1431-43. [PMID: 22302364 DOI: 10.1007/s00726-012-1216-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 01/01/2012] [Indexed: 12/23/2022]
Abstract
Peptides labeled with short-lived positron-emitting radionuclides are of outstanding interest as probes for molecular imaging by positron emission tomography (PET). Herein, the site-selective incorporation of fluorine-18 into lysine-containing peptides using the prosthetic labeling agent N-succinimidyl 4-[(18)F]fluorobenzoate ([(18)F]SFB) is described. The reaction of [(18)F]SFB with four biologically relevant resin-bound peptides was studied and optimized. For comparison, each peptide was 18F-fluorobenzoylated in solution under different conditions and the product distribution was analyzed confirming the advantages of the solid-phase approach. The method's feasibility for selective radiolabeling either at the N-terminus or at the lysine side chain was demonstrated. Labeling on solid phase with [(18)F]SFB resulted in crude (18)F-fluorobenzoylpeptides whose radiochemical purities were typically greater than 90% and that could be prepared in synthesis times from 65 to 76 min.
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Mamat C, Mosch B, Neuber C, Köckerling M, Bergmann R, Pietzsch J. Fluorine-18 Radiolabeling and Radiopharmacological Characterization of a Benzodioxolylpyrimidine-based Radiotracer Targeting the Receptor Tyrosine Kinase EphB4. ChemMedChem 2012; 7:1991-2003. [DOI: 10.1002/cmdc.201200264] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 08/29/2012] [Indexed: 12/24/2022]
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29
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Zozulya SA, Udovichenko IP. [Eph family receptors as therapeutic targets]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2012; 38:267-79. [PMID: 22997698 DOI: 10.1134/s106816201203017x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Anti-angiogenic therapy is currently a commonly accepted and rapidly developing approach in oncology and other pathologies linked to aberrant neovascularization. Discovery and validation of additional molecular targets in angiogenesis is needed due to the limitations of the existing clinical therapeutics inhibiting activity of vascular endothelial growth factor (VEGF) and its receptors. A brief review of normal and pathological biological functions of the Eph family of receptor tyrosine kinases and their ephrin ligands is presented, and the approaches to developing therapeutics with anti- and pro-angiogenic and anti-tumor activity based on selective molecular modulation of Eph-ephrin signaling pairs are discussed. Functional roles of Eph-kinases and ephrins in such mechanisms of cancerogenesis as cell proliferation and invasion are also addressed.
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Salvucci O, Tosato G. Essential roles of EphB receptors and EphrinB ligands in endothelial cell function and angiogenesis. Adv Cancer Res 2012; 114:21-57. [PMID: 22588055 DOI: 10.1016/b978-0-12-386503-8.00002-8] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Eph receptor tyrosine kinases and their Ephrin ligands represent an important signaling system with widespread roles in cell physiology and disease. Receptors and ligands in this family are anchored to the cell surface; thus Eph/Ephrin interactions mainly occur at sites of cell-to-cell contact. EphB4 and EphrinB2 are the Eph/Ephrin molecules that play essential roles in vascular development and postnatal angiogenesis. Analysis of expression patterns and function has linked EphB4/EphrinB2 to endothelial cell growth, survival, migration, assembly, and angiogenesis. Signaling from these molecules is complex, with the potential for being bidirectional, emanating both from the Eph receptors (forward signaling) and from the Ephrin ligands (reverse signaling). In this review, we describe recent advances on the roles of EphB/EphrinB protein family in endothelial cell function and outline potential approaches to inhibit pathological angiogenesis based on this understanding.
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Affiliation(s)
- Ombretta Salvucci
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
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31
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Distinctive binding of three antagonistic peptides to the ephrin-binding pocket of the EphA4 receptor. Biochem J 2012; 445:47-56. [PMID: 22489865 DOI: 10.1042/bj20120408] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The EphA4 receptor tyrosine kinase interacts with ephrin ligands to regulate many processes, ranging from axon guidance and nerve regeneration to cancer malignancy. Thus antagonists that inhibit ephrin binding to EphA4 could be useful for a variety of research and therapeutic applications. In the present study we characterize the binding features of three antagonistic peptides (KYL, APY and VTM) that selectively target EphA4 among the Eph receptors. Isothermal titration calorimetry analysis demonstrated that all three peptides bind to the ephrin-binding domain of EphA4 with low micromolar affinity. Furthermore, the effects of a series of EphA4 mutations suggest that the peptides interact in different ways with the ephrin-binding pocket of EphA4. Chemical-shift changes observed by NMR spectroscopy upon binding of the KYL peptide involve many EphA4 residues, consistent with extensive interactions and possibly receptor conformational changes. Additionally, systematic replacement of each of the 12 amino acids of KYL and VTM identify the residues critical for EphA4, binding. The peptides exhibit a long half-life in cell culture medium which, with their substantial binding affinity and selectivity for EphA4, makes them excellent research tools to modulate EphA4 function.
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32
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Qin H, Lim L, Song J. Protein dynamics at Eph receptor-ligand interfaces as revealed by crystallography, NMR and MD simulations. BMC BIOPHYSICS 2012; 5:2. [PMID: 22277260 PMCID: PMC3274464 DOI: 10.1186/2046-1682-5-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 01/25/2012] [Indexed: 12/21/2022]
Abstract
Background The role of dynamics in protein functions including signal transduction is just starting to be deciphered. Eph receptors with 16 members divided into A- and B- subclasses are respectively activated by 9 A- and B-ephrin ligands. EphA4 is the only receptor capable of binding to all 9 ephrins and small molecules with overlapped interfaces. Results We first determined the structures of the EphA4 ligand binding domain (LBD) in two crystals of P1 space group. Noticeably, 8 EphA4 molecules were found in one asymmetric unit and consequently from two crystals we obtained 16 structures, which show significant conformational variations over the functionally critical A-C, D-E, G-H and J-K loops. The 16 new structures, together with previous 9 ones, can be categorized into two groups: closed and open forms which resemble the uncomplexed and complexed structures of the EphA4 LBD respectively. To assess whether the conformational diversity over the loops primarily results from the intrinsic dynamics, we initiated 30-ns molecular dynamics (MD) simulations for both closed and open forms. The results indicate that the loops do have much higher intrinsic dynamics, which is further unravelled by NMR H/D exchange experiments. During simulations, the open form has the RMS deviations slightly larger than those of the closed one, suggesting the open form may be less stable in the absence of external contacts. Furthermore, no obvious exchange between two forms is observed within 30 ns, implying that they are dynamically separated. Conclusions Our study provides the first experimental and computational result revealing that the intrinsic dynamics are most likely underlying the conformational diversity observed for the EphA4 LBD loops mediating the binding affinity and specificity. Interestingly, the open conformation of the EphA4 LBD is slightly unstable in the absence of it natural ligand ephrins, implying that the conformational transition from the closed to open has to be driven by the high-affinity interaction with ephrins because the weak interaction with small molecule was found to be insufficient to trigger the transition. Our results therefore highlight the key role of protein dynamics in Eph-ephrin signalling and would benefit future design of agonists/antagonists targeting Eph receptors.
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Affiliation(s)
- Haina Qin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Republic of Singapore
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Noberini R, Lamberto I, Pasquale EB. Targeting Eph receptors with peptides and small molecules: progress and challenges. Semin Cell Dev Biol 2011; 23:51-7. [PMID: 22044885 DOI: 10.1016/j.semcdb.2011.10.023] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 10/17/2011] [Indexed: 11/18/2022]
Abstract
The Eph receptors are a large family of receptor tyrosine kinases. Their kinase activity and downstream signaling ability are stimulated by the binding of cell surface-associated ligands, the ephrins. The ensuing signals are bidirectional because the ephrins can also transduce signals (known as reverse signals) following their interaction with Eph receptors. The ephrin-binding pocket in the extracellular N-terminal domain of the Eph receptors and the ATP-binding pocket in the intracellular kinase domain represent potential binding sites for peptides and small molecules. Indeed, a number of peptides and chemical compounds that target Eph receptors and inhibit ephrin binding or kinase activity have been identified. These molecules show promise as probes to study Eph receptor/ephrin biology, as lead compounds for drug development, and as targeting agents to deliver drugs or imaging agents to tumors. Current challenges are to find (1) small molecules that inhibit Eph receptor-ephrin interactions with high binding affinity and good lead-like properties and (2) selective kinase inhibitors that preferentially target the Eph receptor family or subsets of Eph receptors. Strategies that could also be explored include targeting additional Eph receptor interfaces and the ephrin ligands.
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Affiliation(s)
- Roberta Noberini
- Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Rd., La Jolla, CA 92037, USA
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Himanen JP. Ectodomain structures of Eph receptors. Semin Cell Dev Biol 2011; 23:35-42. [PMID: 22044883 DOI: 10.1016/j.semcdb.2011.10.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 10/17/2011] [Indexed: 11/25/2022]
Abstract
Eph receptors, the largest subfamily of receptor tyrosine kinases (RTKs), and their ephrin ligands are important mediators of cell-cell communication that regulate axon guidance, long-term potentiation, and stem cell development, among others. By now, many Eph receptors and ephrins have also been found to play important roles in the progression of cancer. Since both the receptor and the ligand are membrane-bound, their interaction leads to the multimerization of both molecules to distinct clusters within their respective plasma membranes, resulting in the formation of discrete signaling centers. In addition, and unique to Eph receptors and ephrins, their interaction initiates bi-directional signaling cascades where information is transduced in the direction of both the receptor- and the ligand-bearing cells. The Ephs and the ephrins are divided into two subclasses, A and B, based on their affinities for each other and on sequence conservation. Crystal structures and other biophysical studies have indicated that isolated extracellular Eph and ephrin domains initially form high-affinity heterodimers around a hydrophobic loop of the ligand that is buried in a hydrophobic pocket on the surface of the receptor. The dimers can then further arrange by weaker interactions into higher-order Eph/ephrin clusters observed in vivo at the sites of cell-cell contact. Although the hetero-dimerization is a universal way to initiate signaling, other extracellular domains of Ephs are involved in the formation of higher-order clusters. The structures also show important differences defining the unique partner preferences of the two ligand and receptor subclasses, namely, how subclass specificity is determined both by individual interacting residues and by the precise architectural arrangement of ligands and receptors within the complexes.
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Affiliation(s)
- Juha P Himanen
- Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
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35
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Noberini R, De SK, Zhang Z, Wu B, Raveendra-Panickar D, Chen V, Vazquez J, Qin H, Song J, Cosford NDP, Pellecchia M, Pasquale EB. A disalicylic acid-furanyl derivative inhibits ephrin binding to a subset of Eph receptors. Chem Biol Drug Des 2011; 78:667-78. [PMID: 21791013 DOI: 10.1111/j.1747-0285.2011.01199.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Eph receptor tyrosine kinases and ephrin ligands control many physiological and pathological processes, and molecules interfering with their interaction are useful probes to elucidate their complex biological functions. Moreover, targeting Eph receptors might enable new strategies to inhibit cancer progression and pathological angiogenesis as well as promote nerve regeneration. Because our previous work suggested the importance of the salicylic acid group in antagonistic small molecules targeting Eph receptors, we screened a series of salicylic acid derivatives to identify novel Eph receptor antagonists. This identified a disalicylic acid-furanyl derivative that inhibits ephrin-A5 binding to EphA4 with an IC(50) of 3 μm in ELISAs. This compound, which appears to bind to the ephrin-binding pocket of EphA4, also targets several other Eph receptors. Furthermore, it inhibits EphA2 and EphA4 tyrosine phosphorylation in cells stimulated with ephrin while not affecting phosphorylation of EphB2, which is not a target receptor. In endothelial cells, the disalicylic acid-furanyl derivative inhibits EphA2 phosphorylation in response to TNFα and capillary-like tube formation on Matrigel, two effects that depend on EphA2 interaction with endogenous ephrin-A1. These findings suggest that salicylic acid derivatives could be used as starting points to design new small molecule antagonists of Eph receptors.
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Affiliation(s)
- Roberta Noberini
- Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA.
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Arthur A, Zannettino A, Panagopoulos R, Koblar SA, Sims NA, Stylianou C, Matsuo K, Gronthos S. EphB/ephrin-B interactions mediate human MSC attachment, migration and osteochondral differentiation. Bone 2011; 48:533-42. [PMID: 21056708 DOI: 10.1016/j.bone.2010.10.180] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 10/29/2010] [Accepted: 10/29/2010] [Indexed: 01/08/2023]
Abstract
Bone marrow derived mesenchymal stem/stromal cells (MSC) contribute to skeletal tissue formation and the regulation of haematopoiesis. The Eph/ephrin family of receptor tyrosine kinases is potentially important in the maintenance of the stem cell niche within neural, intestinal and dental tissues and has recently been shown to play a role in regulating bone homeostasis. However, the contribution of EphB/ephrin-B molecules in human MSC function remains to be determined. In the present study, EphB and ephrin-B molecules were expressed by ex vivo expanded human MSC populations and within human bone marrow trephine samples. To elucidate the contribution of EphB/ephrin-B molecules in MSC recruitment, we performed functional spreading and migration assays and showed that reverse ephrin-B signalling inhibited MSC attachment and spreading by activating Src-, PI3Kinase- and JNK-dependent signalling pathways. In contrast, forward EphB2 signalling promoted MSC migration by activating the Src kinase- and Abl-dependent signalling pathways. Furthermore, activation of ephrin-B1 and/or ephrin-B2 molecules expressed by MSC was found to increase osteogenic differentiation, while ephrin-B1 activation promoted chondrogenic differentiation. These observations suggest that EphB/ephrin-B interactions may mediate the recruitment, migration and differentiation of MSC during bone repair.
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Affiliation(s)
- Agnieszka Arthur
- Mesenchymal Stem Cell Group, Department of Haematology, Institute of Medical and Veterinary Science/Hanson Institute and Centre for Stem Cell Research/Robinson Institute, University of Adelaide, Adelaide, SA, Australia.
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Eph receptors and ephrin ligands: important players in angiogenesis and tumor angiogenesis. JOURNAL OF ONCOLOGY 2010; 2010:135285. [PMID: 20224755 PMCID: PMC2836134 DOI: 10.1155/2010/135285] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 01/05/2010] [Indexed: 12/24/2022]
Abstract
Eph receptors and their ephrin ligands were identified in the late 1980's. Subsequently, they were linked to different physiological and pathophysiological processes like embryonic development, angiogenesis, and tumorigenesis. In this regard, recent work focused on the distribution and effects of Eph receptors and ephrins on tumor cells and tumor microenvironment. The purpose of this review is to outline the role of these molecules in physiological angiogenesis and pathophysiological tumor angiogenesis. Furthermore, novel therapeutical approaches are discussed as Eph receptors and ephrins represent attractive targets for antiangiogenic therapy.
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Abstract
The Eph receptor tyrosine kinases and their ephrin ligands have intriguing expression patterns in cancer cells and tumour blood vessels, which suggest important roles for their bidirectional signals in many aspects of cancer development and progression. Eph gene mutations probably also contribute to cancer pathogenesis. Eph receptors and ephrins have been shown to affect the growth, migration and invasion of cancer cells in culture as well as tumour growth, invasiveness, angiogenesis and metastasis in vivo. However, Eph signalling activities in cancer seem to be complex, and are characterized by puzzling dichotomies. Nevertheless, the Eph receptors are promising new therapeutic targets in cancer.
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Affiliation(s)
- Elena B Pasquale
- Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA.
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Qin H, Noberini R, Huan X, Shi J, Pasquale EB, Song J. Structural characterization of the EphA4-Ephrin-B2 complex reveals new features enabling Eph-ephrin binding promiscuity. J Biol Chem 2010; 285:644-54. [PMID: 19875447 PMCID: PMC2804212 DOI: 10.1074/jbc.m109.064824] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 10/19/2009] [Indexed: 11/06/2022] Open
Abstract
EphA and EphB receptors preferentially bind ephrin-A and ephrin-B ligands, respectively, but EphA4 is exceptional for its ability to bind all ephrins. Here, we report the crystal structure of the EphA4 ligand-binding domain in complex with ephrin-B2, which represents the first structure of an EphA-ephrin-B interclass complex. A loose fit of the ephrin-B2 G-H loop in the EphA4 ligand-binding channel is consistent with a relatively weak binding affinity. Additional surface contacts also exist between EphA4 residues Gln(12) and Glu(14) and ephrin-B2. Mutation of Gln(12) and Glu(14) does not cause significant structural changes in EphA4 or changes in its affinity for ephrin-A ligands. However, the EphA4 mutant has approximately 10-fold reduced affinity for ephrin-B ligands, indicating that the surface contacts are critical for interclass but not intraclass ephrin binding. Thus, EphA4 uses different strategies to bind ephrin-A or ephrin-B ligands and achieve binding promiscuity. NMR characterization also suggests that the contacts of Gln(12) and Glu(14) with ephrin-B2 induce dynamic changes throughout the whole EphA4 ligand-binding domain. Our findings shed light on the distinctive features that enable the remarkable ligand binding promiscuity of EphA4 and suggest that diverse strategies are needed to effectively disrupt different Eph-ephrin complexes.
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Affiliation(s)
- Haina Qin
- From the Department of Biological Sciences, Faculty of Science
| | - Roberta Noberini
- the Burnham Institute for Medical Research, La Jolla, California 92037, and
| | - Xuelu Huan
- National University of Singapore Graduate School for Integrative Sciences and Engineering, and
| | - Jiahai Shi
- From the Department of Biological Sciences, Faculty of Science
| | - Elena B. Pasquale
- the Burnham Institute for Medical Research, La Jolla, California 92037, and
- the Pathology Department, University of California, San Diego, La Jolla, California 92093
| | - Jianxing Song
- From the Department of Biological Sciences, Faculty of Science
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
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Goldgur Y, Paavilainen S, Nikolov D, Himanen JP. Structure of the ligand-binding domain of the EphB2 receptor at 2 A resolution. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:71-4. [PMID: 19193989 PMCID: PMC2635866 DOI: 10.1107/s1744309108043078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 12/17/2008] [Indexed: 01/03/2023]
Abstract
Eph tyrosine kinase receptors, the largest group of receptor tyrosine kinases, and their ephrin ligands are important mediators of cell-cell communication regulating cell attachment, shape and mobility. Recently, several Eph receptors and ephrins have also been found to play important roles in the progression of cancer. Structural and biophysical studies have established detailed information on the binding and recognition of Eph receptors and ephrins. The initial high-affinity binding of Eph receptors to ephrin occurs through the penetration of an extended G-H loop of the ligand into a hydrophobic channel on the surface of the receptor. Consequently, the G-H loop-binding channel of Eph receptors is the main target in the search for Eph antagonists that could be used in the development of anticancer drugs and several peptides have been shown to specifically bind Eph receptors and compete with the cognate ephrin ligands. However, the molecular details of the conformational changes upon Eph/ephrin binding have remained speculative, since two of the loops were unstructured in the original model of the free EphB2 structure and their conformational changes upon ligand binding could consequently not be analyzed in detail. In this study, the X-ray structure of unbound EphB2 is reported at a considerably higher 2 A resolution, the conformational changes that the important receptor loops undergo upon ligand binding are described and the consequences that these findings have for the development of Eph antagonists are discussed.
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Affiliation(s)
- Yehuda Goldgur
- Structural Biology Program, Memorial Sloan–Kettering Cancer Center, 1275 York Avenue, New York 10065, USA
| | - Sari Paavilainen
- JBL Laboratory, University of Turku, BioCity 6A, 20520 Turku, Finland
| | - Dimitar Nikolov
- Structural Biology Program, Memorial Sloan–Kettering Cancer Center, 1275 York Avenue, New York 10065, USA
| | - J. P. Himanen
- Structural Biology Program, Memorial Sloan–Kettering Cancer Center, 1275 York Avenue, New York 10065, USA
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Vaught D, Brantley-Sieders DM, Chen J. Eph receptors in breast cancer: roles in tumor promotion and tumor suppression. Breast Cancer Res 2008; 10:217. [PMID: 19144211 PMCID: PMC2656900 DOI: 10.1186/bcr2207] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Eph receptor tyrosine kinase signaling regulates cancer initiation and metastatic progression through multiple mechanisms. Studies of tumor-cell-autonomous effects of Eph receptors demonstrate their dual roles in tumor suppression and tumor promotion. In addition, Eph molecules function in the tumor microenvironment, such as in vascular endothelial cells, influencing the ability of these molecules to promote carcinoma progression and metastasis. The complex nature of Eph receptor signaling and crosstalk with other receptor tyrosine kinases presents a unique challenge and an opportunity to develop therapeutic intervention strategies for targeting breast cancer.
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Affiliation(s)
- David Vaught
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Bjelić S, Jelesarov I. A survey of the year 2007 literature on applications of isothermal titration calorimetry. J Mol Recognit 2008; 21:289-312. [PMID: 18729242 DOI: 10.1002/jmr.909] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Elucidation of the energetic principles of binding affinity and specificity is a central task in many branches of current sciences: biology, medicine, pharmacology, chemistry, material sciences, etc. In biomedical research, integral approaches combining structural information with in-solution biophysical data have proved to be a powerful way toward understanding the physical basis of vital cellular phenomena. Isothermal titration calorimetry (ITC) is a valuable experimental tool facilitating quantification of the thermodynamic parameters that characterize recognition processes involving biomacromolecules. The method provides access to all relevant thermodynamic information by performing a few experiments. In particular, ITC experiments allow to by-pass tedious and (rarely precise) procedures aimed at determining the changes in enthalpy and entropy upon binding by van't Hoff analysis. Notwithstanding limitations, ITC has now the reputation of being the "gold standard" and ITC data are widely used to validate theoretical predictions of thermodynamic parameters, as well as to benchmark the results of novel binding assays. In this paper, we discuss several publications from 2007 reporting ITC results. The focus is on applications in biologically oriented fields. We do not intend a comprehensive coverage of all newly accumulated information. Rather, we emphasize work which has captured our attention with originality and far-reaching analysis, or else has provided ideas for expanding the potential of the method.
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Affiliation(s)
- Sasa Bjelić
- Biochemisches Institut der Universität Zürich, Winterthurerstrasse 190, Zürich, Switzerland
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Noberini R, Koolpe M, Peddibhotla S, Dahl R, Su Y, Cosford NDP, Roth GP, Pasquale EB. Small molecules can selectively inhibit ephrin binding to the EphA4 and EphA2 receptors. J Biol Chem 2008; 283:29461-72. [PMID: 18728010 DOI: 10.1074/jbc.m804103200] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The erythropoietin-producing hepatocellular (Eph) family of receptor tyrosine kinases regulates a multitude of physiological and pathological processes. Despite the numerous possible research and therapeutic applications of agents capable of modulating Eph receptor function, no small molecule inhibitors targeting the extracellular domain of these receptors have been identified. We have performed a high throughput screen to search for small molecules that inhibit ligand binding to the extracellular domain of the EphA4 receptor. This yielded a 2,5-dimethylpyrrolyl benzoic acid derivative able to inhibit the interaction of EphA4 with a peptide ligand as well as the natural ephrin ligands. Evaluation of a series of analogs identified an isomer with similar inhibitory properties and other less potent compounds. The two isomeric compounds act as competitive inhibitors, suggesting that they target the high affinity ligand-binding pocket of EphA4 and inhibit ephrin-A5 binding to EphA4 with K(i) values of 7 and 9 mum in enzyme-linked immunosorbent assays. Interestingly, despite the ability of each ephrin ligand to promiscuously bind many Eph receptors, the two compounds selectively target EphA4 and the closely related EphA2 receptor. The compounds also inhibit ephrin-induced phosphorylation of EphA4 and EphA2 in cells, without affecting cell viability or the phosphorylation of other receptor tyrosine kinases. Furthermore, the compounds inhibit EphA4-mediated growth cone collapse in retinal explants and EphA2-dependent retraction of the cell periphery in prostate cancer cells. These data demonstrate that the Eph receptor-ephrin interface can be targeted by inhibitory small molecules and suggest that the two compounds identified will be useful to discriminate the activities of EphA4 and EphA2 from those of other co-expressed Eph receptors that are activated by the same ephrin ligands. Furthermore, the newly identified inhibitors represent possible leads for the development of therapies to treat pathologies in which EphA4 and EphA2 are involved, including nerve injuries and cancer.
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Affiliation(s)
- Roberta Noberini
- Burnham Institute for Medical Research, La Jolla, California 92037, USA
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Qin H, Shi J, Noberini R, Pasquale EB, Song J. Crystal structure and NMR binding reveal that two small molecule antagonists target the high affinity ephrin-binding channel of the EphA4 receptor. J Biol Chem 2008; 283:29473-84. [PMID: 18708347 DOI: 10.1074/jbc.m804114200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The Eph receptor tyrosine kinases regulate a variety of physiological and pathological processes not only during development but also in adult organs, and therefore they represent a promising class of drug targets. The EphA4 receptor plays important roles in the inhibition of the regeneration of injured axons, synaptic plasticity, platelet aggregation, and likely in certain types of cancer. Here we report the first crystal structure of the EphA4 ligand-binding domain, which adopts the same jellyroll beta-sandwich architecture as shown previously for EphB2 and EphB4. The similarity with EphB receptors is high in the core beta-stranded regions, whereas large variations exist in the loops, particularly the D-E and J-K loops, which form the high affinity ephrin binding channel. We also used isothermal titration calorimetry, NMR spectroscopy, and computational docking to characterize the binding to EphA4 of two small molecules, 4- and 5-(2,5 dimethyl-pyrrol-1-yl)-2-hydroxybenzoic acid which antagonize ephrin-induced effects in EphA4-expressing cells. We show that the two molecules bind to the EphA4 ligand-binding domain with K(d) values of 20.4 and 26.4 microm, respectively. NMR heteronuclear single quantum coherence titrations revealed that upon binding, both molecules significantly perturb EphA4 residues Ile(31)-Met(32) in the D-E loop, Gln(43) in the E beta-strand, and Ile(131)-Gly(132) in the J-K loop. Molecular docking shows that they can occupy a cavity in the high affinity ephrin binding channel of EphA4 in a similar manner, by interacting mainly with the EphA4 residues in the E strand and D-E and J-K loops. However, many of the interactions observed in Eph receptor-ephrin complexes are absent, which is consistent with the small size of the two molecules and may account for their relatively weak binding affinity. Thus, our studies provide the first published structure of the ligand-binding domain of an EphA receptor of the A subclass. Furthermore, the results demonstrate that the high affinity ephrin binding channel of the Eph receptors is amenable to targeting with small molecule antagonists and suggest avenues for further optimization.
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Affiliation(s)
- Haina Qin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 11926
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Bowden TA, Aricescu AR, Gilbert RJC, Grimes JM, Jones EY, Stuart DI. Structural basis of Nipah and Hendra virus attachment to their cell-surface receptor ephrin-B2. Nat Struct Mol Biol 2008; 15:567-72. [PMID: 18488039 DOI: 10.1038/nsmb.1435] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 04/28/2008] [Indexed: 11/09/2022]
Abstract
Nipah and Hendra viruses are emergent paramyxoviruses, causing disease characterized by rapid onset and high mortality rates, resulting in their classification as Biosafety Level 4 pathogens. Their attachment glycoproteins are essential for the recognition of the cell-surface receptors ephrin-B2 (EFNB2) and ephrin-B3 (EFNB3). Here we report crystal structures of both Nipah and Hendra attachment glycoproteins in complex with human EFNB2. In contrast to previously solved paramyxovirus attachment complexes, which are mediated by sialic acid interactions, the Nipah and Hendra complexes are maintained by an extensive protein-protein interface, including a crucial phenylalanine side chain on EFNB2 that fits snugly into a hydrophobic pocket on the viral protein. By analogy with the development of antivirals against sialic acid binding viruses, these results provide a structural template to target antiviral inhibition of protein-protein interactions.
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Affiliation(s)
- Thomas A Bowden
- Division of Structural Biology, University of Oxford, Henry Wellcome Building of Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN, UK
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