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Abstract
Cytokines signal through specific cell surface receptors to broadly regulate immune development, differentiation, proliferation, and survival, thereby influencing cellular fate and function. Accordingly, cytokines are potential therapeutic targets for modulation of immune responses. Indeed, over the last several decades, an increasing number of cytokine-based clinical trials have been performed, collectively using either recombinant forms of cytokines or blocking agents that modulate the actions of cytokines. The pleiotropic actions of cytokines, including their abilities to mediate both inflammatory and protective immune responses, indicate that using or targeting cytokines can have desired but also potentially undesirable effects. Here, we focus on the immunomodulatory cytokine, IL-2. We review the underlying basic science related to IL-2 and its biologic actions, discuss the current state of IL-2-based immunotherapy, and focus on emerging concepts of modulating the activities of this cytokine, including the generation of novel partial cytokine agonists as new potential therapeutics.
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Affiliation(s)
- Suman Mitra
- Respiratory, Inflammatory and Autoimmune Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Warren J Leonard
- Laboratory of Molecular Immunology and the Immunology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, USA
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Bresnick EH, Hewitt KJ, Mehta C, Keles S, Paulson RF, Johnson KD. Mechanisms of erythrocyte development and regeneration: implications for regenerative medicine and beyond. Development 2018; 145:145/1/dev151423. [PMID: 29321181 DOI: 10.1242/dev.151423] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hemoglobin-expressing erythrocytes (red blood cells) act as fundamental metabolic regulators by providing oxygen to cells and tissues throughout the body. Whereas the vital requirement for oxygen to support metabolically active cells and tissues is well established, almost nothing is known regarding how erythrocyte development and function impact regeneration. Furthermore, many questions remain unanswered relating to how insults to hematopoietic stem/progenitor cells and erythrocytes can trigger a massive regenerative process termed 'stress erythropoiesis' to produce billions of erythrocytes. Here, we review the cellular and molecular mechanisms governing erythrocyte development and regeneration, and discuss the potential links between these events and other regenerative processes.
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Affiliation(s)
- Emery H Bresnick
- Department of Cell and Regenerative Biology, UW-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Kyle J Hewitt
- Department of Cell and Regenerative Biology, UW-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Charu Mehta
- Department of Cell and Regenerative Biology, UW-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Sunduz Keles
- Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Robert F Paulson
- Department of Veterinary and Biomedical Sciences, Center for Molecular Immunology and Infectious Disease, Penn State University, University Park, PA 16802, USA
| | - Kirby D Johnson
- Department of Cell and Regenerative Biology, UW-Madison Blood Research Program, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
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Freed DM, Bessman NJ, Kiyatkin A, Salazar-Cavazos E, Byrne PO, Moore JO, Valley CC, Ferguson KM, Leahy DJ, Lidke DS, Lemmon MA. EGFR Ligands Differentially Stabilize Receptor Dimers to Specify Signaling Kinetics. Cell 2017; 171:683-695.e18. [PMID: 28988771 DOI: 10.1016/j.cell.2017.09.017] [Citation(s) in RCA: 229] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 07/31/2017] [Accepted: 09/12/2017] [Indexed: 12/21/2022]
Abstract
Epidermal growth factor receptor (EGFR) regulates many crucial cellular programs, with seven different activating ligands shaping cell signaling in distinct ways. Using crystallography and other approaches, we show how the EGFR ligands epiregulin (EREG) and epigen (EPGN) stabilize different dimeric conformations of the EGFR extracellular region. As a consequence, EREG or EPGN induce less stable EGFR dimers than EGF-making them partial agonists of EGFR dimerization. Unexpectedly, this weakened dimerization elicits more sustained EGFR signaling than seen with EGF, provoking responses in breast cancer cells associated with differentiation rather than proliferation. Our results reveal how responses to different EGFR ligands are defined by receptor dimerization strength and signaling dynamics. These findings have broad implications for understanding receptor tyrosine kinase (RTK) signaling specificity. Our results also suggest parallels between partial and/or biased agonism in RTKs and G-protein-coupled receptors, as well as new therapeutic opportunities for correcting RTK signaling output.
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Affiliation(s)
- Daniel M Freed
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Nicholas J Bessman
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-6059, USA
| | - Anatoly Kiyatkin
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Emanuel Salazar-Cavazos
- Department of Pathology and UNM Comprehensive Cancer Center, University of New Mexico Health Science Center, Albuquerque, NM 87131, USA
| | - Patrick O Byrne
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Jason O Moore
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-6059, USA
| | - Christopher C Valley
- Department of Pathology and UNM Comprehensive Cancer Center, University of New Mexico Health Science Center, Albuquerque, NM 87131, USA
| | - Kathryn M Ferguson
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Daniel J Leahy
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Diane S Lidke
- Department of Pathology and UNM Comprehensive Cancer Center, University of New Mexico Health Science Center, Albuquerque, NM 87131, USA
| | - Mark A Lemmon
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-6059, USA.
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54
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A ligand divided: antagonist, agonist and analog control. Biochem J 2017; 474:3087-3088. [PMID: 28860336 DOI: 10.1042/bcj20170495] [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: 07/18/2017] [Revised: 08/01/2017] [Accepted: 08/02/2017] [Indexed: 11/17/2022]
Abstract
Inhibiting receptor tyrosine kinases has been a cornerstone of cancer therapeutics for decades. Treatment strategies largely involve small-molecule kinase inhibitors and monoclonal antibodies. For receptors activated by constitutively dimeric ligands, another potential mechanism of inhibition exists: developing monomeric ligands that prevent receptor dimerization. In a recent issue of the Biochemical Journal, Zur et al. [Biochem. J. (2017) 474, 2601-2617] describe the details of creating such an inhibitor directed toward the macrophage colony-stimulating factor receptor, c-FMS. In the process of teasing apart the ligand dimer, they also uncover a potential cryptic regulatory mechanism in this receptor subfamily.
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