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Milewska-Kranc A, Ćwikła JB, Kolasinska-Ćwikła A. The Role of Receptor-Ligand Interaction in Somatostatin Signaling Pathways: Implications for Neuroendocrine Tumors. Cancers (Basel) 2023; 16:116. [PMID: 38201544 PMCID: PMC10778465 DOI: 10.3390/cancers16010116] [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: 11/28/2023] [Revised: 12/19/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Neuroendocrine tumors (NETs) arise from neuroendocrine cells and manifest in diverse organs. Key players in their regulation are somatostatin and its receptors (SSTR1-SSTR5). Understanding receptor-ligand interactions and signaling pathways is vital for elucidating their role in tumor development and therapeutic potential. This review highlights SSTR characteristics, localization, and expression in tissues, impacting physiological functions. Mechanisms of somatostatin and synthetic analogue binding to SSTRs, their selectivity, and their affinity were analyzed. Upon activation, somatostatin initiates intricate intracellular signaling, involving cAMP, PLC, and MAP kinases and influencing growth, differentiation, survival, and hormone secretion in NETs. This review explores SSTR expression in different tumor types, examining receptor activation effects on cancer cells. SSTRs' significance as therapeutic targets is discussed. Additionally, somatostatin and analogues' role in hormone secretion regulation, tumor growth, and survival is emphasized, presenting relevant therapeutic examples. In conclusion, this review advances the knowledge of receptor-ligand interactions and signaling pathways in somatostatin receptors, with potential for improved neuroendocrine tumor treatments.
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Affiliation(s)
| | - Jarosław B. Ćwikła
- School of Medicine, University of Warmia and Mazury, Aleja Warszawska 30, 10-082 Olsztyn, Poland
- Diagnostic Therapeutic Center–Gammed, Lelechowska 5, 02-351 Warsaw, Poland
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Feng S, Tong H, Gao JH, Tang SH, Yang WJ, Wang GM, Zhou HY, Wen SL. Anti-inflammation treatment for protection of hepatocytes and amelioration of hepatic fibrosis in rats. Exp Ther Med 2021; 22:1213. [PMID: 34584558 PMCID: PMC8422404 DOI: 10.3892/etm.2021.10647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 06/11/2021] [Indexed: 02/05/2023] Open
Abstract
Chronic inflammation is considered as an important pathophysiologic mechanism of hepatic cirrhosis, which induces hepatocyte injury and activates hepatic stellate cells (HSCs), thus resulting in hepatic fibrosis. Previous studies have reported that cyclooxygenase-2 (COX-2) inhibitor can effectively treat liver fibrosis, while somatostatin (SST) analogues inhibit the activation of HSCs. The present study aimed to investigate the effects of a COX-2 inhibitor, celecoxib, combined with a SST analogue, octreotide, for protection of hepatocytes and prevention of fibrosis in a rat model of hepatic fibrosis. Therefore, a hepatic fibrosis rat model was established following peritoneal injection of thioacetamide (TAA), and the rats were then treated with a combination of celecoxib and octreotide (TAA + C). Immunohistochemistry and western blotting assays were used to assess the expression levels of proteins associated with inflammation, epithelial-mesenchymal transition (EMT), proliferation, apoptosis and autophagy. H&E staining, transmission electron microscopy and scanning electron microscopy were used to evaluate the destruction of hepatocytes. Masson's Trichrome and Sirius Red were used to measure the degree of liver fibrosis. The results demonstrated that, compared with those of the control group, the degree of liver fibrosis and the expression of the intrahepatic inflammation factors were aggravated in the TAA group. Furthermore, the apoptosis rate, EMT and autophagy of hepatocytes were also increased in the TAA group. However, treatment with TAA + C restored the aforementioned increased levels compared with the TAA group. In conclusion, treatment of rats with the combination of celecoxib and octreotide could attenuate the progress of hepatic fibrosis via protection of hepatocytes by reducing apoptosis, EMT and autophagy in hepatocytes.
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Affiliation(s)
- Shi Feng
- Key Laboratory of Brain Science Research and Transformation in Tropical Environment of Hainan Province, Hainan Medical University, Haikou, Hainan 571199, P.R. China
| | - Huan Tong
- Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Jin-Hang Gao
- Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Shi-Hang Tang
- Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Wen-Juan Yang
- Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Gui-Ming Wang
- Department of Human Anatomy, West China School of Basic Medical Science and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Hong-Ying Zhou
- Department of Human Anatomy, West China School of Basic Medical Science and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Shi-Lei Wen
- Key Laboratory of Brain Science Research and Transformation in Tropical Environment of Hainan Province, Hainan Medical University, Haikou, Hainan 571199, P.R. China
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Ramírez-Rentería C, Ferreira-Hermosillo A, Marrero-Rodríguez D, Taniguchi-Ponciano K, Melgar-Manzanilla V, Mercado M. An Update on Gastroenteropancreatic Neuroendocrine Neoplasms: From Mysteries to Paradigm Shifts. Arch Med Res 2020; 51:765-776. [PMID: 32654882 DOI: 10.1016/j.arcmed.2020.06.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 06/23/2020] [Accepted: 06/30/2020] [Indexed: 02/07/2023]
Abstract
Although neuroendocrine neoplasms (NEN) were once thought to be rare and mostly "benign" diseases, they are now being redefined in light of recently discovered molecular information. NENs constitute a spectrum of variably differentiated neoplasms, ranging from well-differentiated tumors with a protracted course over many years to very aggressive neuroendocrine carcinomas. Although the majority of NEN are non-functional lesions, some of these tumors, do produce a hormonal hypersecretion syndrome. Their reappraisal has led scientist to unveil previously unknown oncogenic pathways and connections that resulted in a new category in the International Classification of Diseases (ICD-11) and a revised version of the World Health Organization Classification (WHO 2018). Complex diseases like NEN require a multidisciplinary approach that includes the perspectives of endocrinologists, medical and surgical oncologists, radiation oncologists, imaging specialists and pathologists. There are currently virtually thousands of ongoing trials evaluating the efficacy and safety of several molecular targeted therapies. The purpose of this review was to critically evaluate recent information regarding the pathogenesis, diagnosis and treatment of NEN.
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Affiliation(s)
- Claudia Ramírez-Rentería
- Unidad de Investigación Médica en Enfermedades Endocrinas. Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | - Aldo Ferreira-Hermosillo
- Unidad de Investigación Médica en Enfermedades Endocrinas. Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | - Daniel Marrero-Rodríguez
- Unidad de Investigación Médica en Enfermedades Endocrinas. Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | - Keiko Taniguchi-Ponciano
- Unidad de Investigación Médica en Enfermedades Endocrinas. Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | - Virgilio Melgar-Manzanilla
- Unidad de Investigación Médica en Enfermedades Endocrinas. Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | - Moisés Mercado
- Unidad de Investigación Médica en Enfermedades Endocrinas. Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México.
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Kumar U, Singh S. Role of Somatostatin in the Regulation of Central and Peripheral Factors of Satiety and Obesity. Int J Mol Sci 2020; 21:ijms21072568. [PMID: 32272767 PMCID: PMC7177963 DOI: 10.3390/ijms21072568] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/29/2020] [Accepted: 04/02/2020] [Indexed: 02/06/2023] Open
Abstract
Obesity is one of the major social and health problems globally and often associated with various other pathological conditions. In addition to unregulated eating behaviour, circulating peptide-mediated hormonal secretion and signaling pathways play a critical role in food intake induced obesity. Amongst the many peptides involved in the regulation of food-seeking behaviour, somatostatin (SST) is the one which plays a determinant role in the complex process of appetite. SST is involved in the regulation of release and secretion of other peptides, neuronal integrity, and hormonal regulation. Based on past and recent studies, SST might serve as a bridge between central and peripheral tissues with a significant impact on obesity-associated with food intake behaviour and energy expenditure. Here, we present a comprehensive review describing the role of SST in the modulation of multiple central and peripheral signaling molecules. In addition, we highlight recent progress and contribution of SST and its receptors in food-seeking behaviour, obesity (orexigenic), and satiety (anorexigenic) associated pathways and mechanism.
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Riedemann T, Sutor B. Long-lasting actions of somatostatin on pyramidal cell excitability in the mouse cingulate cortex. Neurosci Lett 2019; 698:217-223. [PMID: 30668961 DOI: 10.1016/j.neulet.2019.01.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/10/2019] [Accepted: 01/18/2019] [Indexed: 02/07/2023]
Abstract
Many neurological diseases are related to disturbances of somatostatin- (SOM-) expressing interneurons in the cingulate cortex. Therefore, their role within the circuitry of the cingulate cortex needs to be investigated. We describe here the physiological time course of SOM effects onto pyramidal cell excitability and action potential discharge pattern. Furthermore, we show that the GRK2 inhibitor Gallein had no effect on the reduced SOM-induced response following repetitive SOM applications.
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Affiliation(s)
- Therese Riedemann
- Biomedical Center, Ludwig-Maximilians-Universität, Physiological Genomics, Großhaderner Str. 9, 82152 Planegg-Martinsried, Germany.
| | - Bernd Sutor
- Biomedical Center, Ludwig-Maximilians-Universität, Physiological Genomics, Großhaderner Str. 9, 82152 Planegg-Martinsried, Germany
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Günther T, Tulipano G, Dournaud P, Bousquet C, Csaba Z, Kreienkamp HJ, Lupp A, Korbonits M, Castaño JP, Wester HJ, Culler M, Melmed S, Schulz S. International Union of Basic and Clinical Pharmacology. CV. Somatostatin Receptors: Structure, Function, Ligands, and New Nomenclature. Pharmacol Rev 2019; 70:763-835. [PMID: 30232095 PMCID: PMC6148080 DOI: 10.1124/pr.117.015388] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Somatostatin, also known as somatotropin-release inhibitory factor, is a cyclopeptide that exerts potent inhibitory actions on hormone secretion and neuronal excitability. Its physiologic functions are mediated by five G protein-coupled receptors (GPCRs) called somatostatin receptor (SST)1-5. These five receptors share common structural features and signaling mechanisms but differ in their cellular and subcellular localization and mode of regulation. SST2 and SST5 receptors have evolved as primary targets for pharmacological treatment of pituitary adenomas and neuroendocrine tumors. In addition, SST2 is a prototypical GPCR for the development of peptide-based radiopharmaceuticals for diagnostic and therapeutic interventions. This review article summarizes findings published in the last 25 years on the physiology, pharmacology, and clinical applications related to SSTs. We also discuss potential future developments and propose a new nomenclature.
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Affiliation(s)
- Thomas Günther
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Giovanni Tulipano
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Pascal Dournaud
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Corinne Bousquet
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Zsolt Csaba
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Hans-Jürgen Kreienkamp
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Amelie Lupp
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Márta Korbonits
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Justo P Castaño
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Hans-Jürgen Wester
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Michael Culler
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Shlomo Melmed
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
| | - Stefan Schulz
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (T.G., A.L., S.S.); Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy (G.T.); PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France (P.D., Z.C.); Cancer Research Center of Toulouse, INSERM UMR 1037-University Toulouse III Paul Sabatier, Toulouse, France (C.B.); Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (H.-J.K.); Centre for Endocrinology, William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, United Kingdom (M.K.); Maimonides Institute for Biomedical Research of Cordoba, Córdoba, Spain (J.P.C.); Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain (J.P.C.); Reina Sofia University Hospital, Córdoba, Spain (J.P.C.); CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain (J.P.C.); Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany (H.-J.W.); Culler Consulting LLC, Hopkinton, Massachusetts (M.C.); and Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California (S.M.)
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7
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Abstract
Neuroendocrine neoplasms (NEN) are rare and heterogeneous. Therefore, they often remain unrecognized for many years, causing significant disease burden. We here report on four unusual NEN presentations including a metastatic NEN of the kidney, hypoglycemia caused by an insulin-like growth factor-2-oma (previously called non-islet-cell tumor hypoglycemia), multifocal pheochromocytoma in von Hippel Lindau syndrome, and ileal NEN metastatic to the heart. One could say that each one of these tumors were "black swans" and learning about them will increase further awareness of the spectrum of NEN.
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Affiliation(s)
- Christian A Koch
- Medicover GmbH, Berlin / Hannover, Germany.
- Carl von Ossietzky University of Oldenburg, Oldenburg, Germany.
- Technical University of Dresden, Dresden, Germany.
- University of Louisville, Louisville, KY, USA.
| | - S Petersenn
- ENDOC Center for Endocrine Tumors, Hamburg, Germany
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8
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Weiss J, Wood AJ, Zajac JD, Grossmann M, Andrikopoulos S, Ekinci EI. Diabetic ketoacidosis in acromegaly; a rare complication precipitated by corticosteroid use. Diabetes Res Clin Pract 2017; 134:29-37. [PMID: 28951345 DOI: 10.1016/j.diabres.2017.08.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/16/2017] [Accepted: 08/30/2017] [Indexed: 11/29/2022]
Abstract
Diabetic ketoacidosis has been described in the literature as a rare possible initial presentation of acromegaly before a diagnosis of acromegaly is eventually made. Indeed, diabetic ketoacidosis is a recognised complication of acromegaly. There are a number of factors that can predispose patients with acromegaly to diabetes as well as to diabetic ketoacidosis. These include high levels of growth hormone and insulin-like growth factor 1 in acromegaly and the effect on glycaemia by medications used in the management of acromegaly. Ketoacidosis has been described in patients with acromegaly even without the presence of an underlying autoimmune diabetes. Patients with acromegaly and ketoacidosis often respond to treatment and may not require long-term insulin.
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Affiliation(s)
- Jeremy Weiss
- Department of Endocrinology, Austin Health, Level 2 Centaur Building, Repatriation Campus Heidelberg West, Victoria 3084, Australia
| | - Anna J Wood
- Department of Endocrinology, Austin Health, Level 2 Centaur Building, Repatriation Campus Heidelberg West, Victoria 3084, Australia
| | - Jeffrey D Zajac
- Department of Endocrinology, Austin Health, Level 2 Centaur Building, Repatriation Campus Heidelberg West, Victoria 3084, Australia; Department of Medicine, Austin Health and the University of Melbourne (Austin Campus), Parkville, VIC 3010, Australia
| | - Mathis Grossmann
- Department of Endocrinology, Austin Health, Level 2 Centaur Building, Repatriation Campus Heidelberg West, Victoria 3084, Australia
| | - Sofianos Andrikopoulos
- Department of Medicine, Austin Health and the University of Melbourne (Austin Campus), Parkville, VIC 3010, Australia
| | - Elif I Ekinci
- Department of Endocrinology, Austin Health, Level 2 Centaur Building, Repatriation Campus Heidelberg West, Victoria 3084, Australia; Department of Medicine, Austin Health and the University of Melbourne (Austin Campus), Parkville, VIC 3010, Australia.
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9
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Gatto F, Biermasz NR, Feelders RA, Kros JM, Dogan F, van der Lely AJ, Neggers SJCMM, Lamberts SWJ, Pereira AM, Ferone D, Hofland LJ. Low beta-arrestin expression correlates with the responsiveness to long-term somatostatin analog treatment in acromegaly. Eur J Endocrinol 2016; 174:651-62. [PMID: 26888629 DOI: 10.1530/eje-15-0391] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 02/17/2016] [Indexed: 12/18/2022]
Abstract
OBJECTIVE The high expression of somatostatin receptor subtype 2 (SSTR2 also known as sst2) usually present in growth hormone (GH)-secreting adenomas is the rationale for therapy with somatostatin analogs (SSAs) in acromegaly. Although SSTR2 expression is a good predictor for biochemical response to SSA treatment, we still face tumors resistant to SSAs despite high SSTR2 expression. Recently, beta-arrestins (β-arrestins) have been highlighted as key players in the regulation of SSTR2 function. DESIGN To investigate whether β-arrestins might be useful predictors of responsiveness to long-term SSA treatment in acromegaly, we retrospectively evaluated 35 patients with acromegaly who underwent adenomectomy in two referral centers in The Netherlands. METHODS β-arrestin mRNA levels were evaluated in adenoma samples, together with SSTR2 (and SSTR5) mRNA and protein expression. Biochemical response to long-term SSA treatment (median 12 months) was assessed in 32 patients. RESULTS β-arrestin 1 and 2 mRNA was significantly lower in adenoma tissues from patients who achieved insulin-like growth factor 1 normalization (P = 0.024 and P = 0.047) and complete biochemical control (P = 0.047 and P = 0.039). The SSTR2 mRNA was higher in SSA responder patients compared with the resistant ones (P = 0.026). This difference was more evident when analyzing the SSTR2/β-arrestin 1 and SSTR2/β-arrestin 2 ratio (P = 0.011 and P = 0.010). β-arrestin 1 and 2 expression showed a significant trend of higher median values from full responders, partial responders to resistant patients (P = 0.045 and P = 0.021, respectively). Interestingly, SSTR2 protein expression showed a strong inverse correlation with both β-arrestin 1 and 2 mRNA (ρ = -0.69, P = 0.0011 and ρ = -0.67, P = 0.0016). CONCLUSIONS Low β-arrestin expression and high SSTR2/β-arrestin ratio correlate with the responsiveness to long-term treatment with SSAs in patients with acromegaly.
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Affiliation(s)
- Federico Gatto
- Department of Internal MedicineDivision Endocrinology, Erasmus MC, Rotterdam, The Netherlands
| | - Nienke R Biermasz
- Department of MedicineDivision of Endocrinology and Center for Endocrine Tumors, Leiden University Medical Center, Leiden, The Netherlands
| | - Richard A Feelders
- Department of Internal MedicineDivision Endocrinology, Erasmus MC, Rotterdam, The Netherlands Pituitary Center RotterdamErasmus MC, Rotterdam, The Netherlands
| | - Johan M Kros
- PathologyErasmus MC, Rotterdam, The Netherlands Pituitary Center RotterdamErasmus MC, Rotterdam, The Netherlands
| | - Fadime Dogan
- Department of Internal MedicineDivision Endocrinology, Erasmus MC, Rotterdam, The Netherlands
| | - Aart-Jan van der Lely
- Department of Internal MedicineDivision Endocrinology, Erasmus MC, Rotterdam, The Netherlands Pituitary Center RotterdamErasmus MC, Rotterdam, The Netherlands
| | - Sebastian J C M M Neggers
- Department of Internal MedicineDivision Endocrinology, Erasmus MC, Rotterdam, The Netherlands Pituitary Center RotterdamErasmus MC, Rotterdam, The Netherlands
| | - Steven W J Lamberts
- Department of Internal MedicineDivision Endocrinology, Erasmus MC, Rotterdam, The Netherlands
| | - Alberto M Pereira
- Department of MedicineDivision of Endocrinology and Center for Endocrine Tumors, Leiden University Medical Center, Leiden, The Netherlands
| | - Diego Ferone
- EndocrinologyDepartment of Internal Medicine and Medical Specialties (DIMI) and Center of Excellence for Biomedical Research (CEBR), IRCCS AOU San Martino-IST, University of Genoa, Genoa, Italy
| | - Leo J Hofland
- Department of Internal MedicineDivision Endocrinology, Erasmus MC, Rotterdam, The Netherlands Pituitary Center RotterdamErasmus MC, Rotterdam, The Netherlands
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10
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Zou J, Redmond AK, Qi Z, Dooley H, Secombes CJ. The CXC chemokine receptors of fish: Insights into CXCR evolution in the vertebrates. Gen Comp Endocrinol 2015; 215:117-31. [PMID: 25623148 DOI: 10.1016/j.ygcen.2015.01.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 01/12/2015] [Accepted: 01/13/2015] [Indexed: 12/15/2022]
Abstract
This article will review current knowledge on CXCR in fish, that represent three distinct vertebrate groups: Agnatha (jawless fishes), Chondrichthyes (cartilaginous fishes) and Osteichthyes (bony fishes). With the sequencing of many fish genomes, information on CXCR in these species in particular has expanded considerably. In mammals, 6 CXCRs have been described, and their homologues will be initially reviewed before considering a number of atypical CXCRs and a discussion of CXCR evolution.
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Affiliation(s)
- Jun Zou
- Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen AB24 2TZ, UK; School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.
| | - Anthony K Redmond
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK; Centre for Genome-Enabled Biology and Medicine, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Zhitao Qi
- Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen AB24 2TZ, UK; Key Laboratory of Aquaculture and Ecology of Coastal Pools of Jiangsu Province, Department of Ocean Technology, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, China
| | - Helen Dooley
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Chris J Secombes
- Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen AB24 2TZ, UK; School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
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11
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Cytoplasmic expression of SSTR2 and 5 by immunohistochemistry and by RT/PCR is not associated with the pharmacological response to octreotide. ACTA ACUST UNITED AC 2014; 61:523-30. [DOI: 10.1016/j.endonu.2014.05.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 05/03/2014] [Accepted: 05/08/2014] [Indexed: 12/30/2022]
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12
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Chen W, Ke JB, Wu HJ, Miao Y, Li F, Yang XL, Wang Z. Somatostatin receptor-mediated suppression of gabaergic synaptic transmission in cultured rat retinal amacrine cells. Neuroscience 2014; 273:118-27. [PMID: 24846611 DOI: 10.1016/j.neuroscience.2014.05.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 05/05/2014] [Accepted: 05/06/2014] [Indexed: 01/03/2023]
Abstract
Somatostatin (SRIF) modulates neurotransmitter release by activating the specific receptors (sst1-sst5). Our previous study showed that sst5 receptors are expressed in rat retinal GABAergic amacrine cells. Here, we investigated modulation of GABA release by SRIF in cultured amacrine cells, using patch-clamp techniques. The frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in the amacrine cells was significantly reduced by SRIF, which was partially reversed by BIM 23056, an sst5 receptor antagonist, and was further rescued by addition of CYN-154806, an sst2 receptor antagonist. Both nimodipine, an L-type Ca2+ channel blocker, and ω-conotoxin GVIA, an N-type Ca2+ channel blocker, suppressed the sIPSC frequency, and in the presence of nimodipine and ω-conotoxin GVIA, SRIF failed to further suppress the sIPSC frequency. Extracellular application of forskolin, an activator of adenylate cyclase, increased the sIPSC frequency, while the membrane permeable protein kinase A (PKA) inhibitor Rp-cAMP reduced it, and in the presence of Rp-cAMP, SRIF did not change sIPSCs. However, SRIF persisted to suppress the sIPSCs in the presence of KT5823, a protein kinase G (PKG) inhibitor. Moreover, pre-incubation with Bis IV, a protein kinase C (PKC) inhibitor, or pre-application of xestospongin C, an inositol 1,4,5-trisphosphate receptor (IP3R) inhibitor, SRIF still suppressed the sIPSC frequency. All these results suggest that SRIF suppresses GABA release from the amacrine cells by inhibiting presynaptic Ca2+ channels, in part through activating sst5/sst2 receptors, a process that is mediated by the intracellular cAMP-PKA signaling pathway.
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Affiliation(s)
- W Chen
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - J B Ke
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - H J Wu
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - Y Miao
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - F Li
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - X L Yang
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - Z Wang
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China.
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13
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Barbieri F, Albertelli M, Grillo F, Mohamed A, Saveanu A, Barlier A, Ferone D, Florio T. Neuroendocrine tumors: insights into innovative therapeutic options and rational development of targeted therapies. Drug Discov Today 2014; 19:458-68. [DOI: 10.1016/j.drudis.2013.10.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 09/02/2013] [Accepted: 10/21/2013] [Indexed: 02/07/2023]
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14
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Peng Y, Deng L, Ding Y, Chen Q, Wu Y, Yang M, Wang Y, Fu Q. Comparative study of somatostatin-human serum albumin fusion proteins and natural somatostatin on receptor binding, internalization and activation. PLoS One 2014; 9:e89932. [PMID: 24587133 PMCID: PMC3937410 DOI: 10.1371/journal.pone.0089932] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 01/25/2014] [Indexed: 01/08/2023] Open
Abstract
Albumin fusion technology, the combination of small molecular proteins or peptides with human serum albumin (HSA), is an effective method for improving the medicinal values of natural small molecular proteins or peptides. However, comparative studies between HSA-fusion proteins or peptides and the parent small molecules in biological and molecular mechanisms are less reported. In this study, we examined the binding property of two novel somatostatin-HSA fusion proteins, (SST14)2-HSA and (SST28)2-HSA, to human SSTRs in stably expressing SSTR1-5 HEK 293 cells; observed the regulation of receptor internalization and internalized receptor recycling; and detected the receptors activation of HSA fusion proteins in stably expressing SSTR2- and SSTR3-EGFP cells. We showed that both somatostatin-HSA fusion proteins had high affinity to all five SSTRs, stimulated the ERK1/2 phosphorylation and persistently inhibited the accumulation of forskolin-stimulated cAMP in SSTR2- and SSTR3-expressing cells; but were less potent than the synthetic somatostatin-14 (SST-14). Our experiments also showed that somatostatin-HSA fusion proteins did not induce the receptors internalization; rather, they accelerated the recycling of the internalized receptors induced by SST-14 to the plasma membrane. Our results indicated that somatostatin-HSA fusion proteins, different from SST-14, exhibit some particular properties in binding, regulating, and activating somatostatin receptors.
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Affiliation(s)
- Ying Peng
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China
| | - Lili Deng
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China
| | - Yuedi Ding
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China
| | - Quancheng Chen
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China
| | - Yu Wu
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China
| | - Meilin Yang
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China
- The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yaping Wang
- Wuxi Second People’s Hospital of Nanjing Medical University, Wuxi, Jiangsu, China
- * E-mail: (YW); (QF)
| | - Qiang Fu
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China
- * E-mail: (YW); (QF)
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15
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Ruscica M, Magni P, Steffani L, Gatto F, Albertelli M, Rametta R, Valenti L, Ameri P, Magnaghi V, Culler MD, Minuto F, Ferone D, Arvigo M. Characterization and sub-cellular localization of SS1R, SS2R, and SS5R in human late-stage prostate cancer cells: effect of mono- and bi-specific somatostatin analogs on cell growth. Mol Cell Endocrinol 2014; 382:860-70. [PMID: 24211300 DOI: 10.1016/j.mce.2013.10.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 10/24/2013] [Accepted: 10/24/2013] [Indexed: 01/10/2023]
Abstract
Somatostatin (SST) and SST receptors (SS1R, SS2R, SS3R, SS4R and SS5R) appear to play a significant role in the progression of human prostate cancer (PCa), which is associated with heterogeneity of SSRs expression and specific cell localization as we already demonstrated in the LNCaP cell line, an in vitro model of human androgen-dependent PCa. In this study, PC-3 and DU-145 human castration-resistant PCa cells were found to express all SSRs, while LNCaP expressed all but SS4R. A 48-h treatment with BIM-23244 (SS2R/SS5R) or BIM-23926 (SS1R) SST analogs was more effective in inhibiting cell proliferation, compared to BIM-23120 (SS2R), BIM-23206 (SS5R) and BIM-23704 (SS1R/SS2R). BIM-23926 (SS1R) treatment increased the amount of p21 and decreased phosphorylated (p) ERK1/2. BIM-23244 (SS2R/SS5R) led to p21 increment only in PC-3 cells, and to pERK1/2 reduction in both cell lines. SS1R/SS2R and SS2R/SS5R receptor dimers were natively present on cell membrane and their amount was increased by BIM-23704 (SS1R/SS2R) or BIM-23244 (SS2R/SS5R) treatment, respectively. SS1R, SS2R and SS5R were differently distributed among nuclear, lysosomal and microsomal compartment, according to their different recycling dynamics. These results show that, in PC-3, DU-145 and LNCaP cells, activation of SS1R and SS2R/SS5R leads to relevant antiproliferative effects.
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Affiliation(s)
- M Ruscica
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - P Magni
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - L Steffani
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - F Gatto
- Department of Internal Medicine and Medical Specialities & Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, Università di Genova, Italy
| | - M Albertelli
- Department of Internal Medicine and Medical Specialities & Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, Università di Genova, Italy
| | - R Rametta
- Pathophysiology and Transplantation, Università degli Studi di Milano, UO Medicina Interna 1B, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Italy
| | - L Valenti
- Pathophysiology and Transplantation, Università degli Studi di Milano, UO Medicina Interna 1B, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Italy
| | - P Ameri
- Department of Internal Medicine and Medical Specialities & Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, Università di Genova, Italy
| | - V Magnaghi
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - M D Culler
- Biomeasure Incorporated/IPSEN, Milford, MA, USA
| | - F Minuto
- Department of Internal Medicine and Medical Specialities & Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, Università di Genova, Italy
| | - D Ferone
- Department of Internal Medicine and Medical Specialities & Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, Università di Genova, Italy.
| | - M Arvigo
- Department of Internal Medicine and Medical Specialities & Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, Università di Genova, Italy
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16
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Abstract
The peptide hormone somatostatin (SST) is produced in the brain, the gut, and in δ-cells in pancreatic islets of Langerhans. SST secretion from δ-cells is stimulated by glucose, amino acids, and glucagon-like peptide-1. Exogenous SST strongly inhibits the secretion of the blood glucose-regulating hormones insulin and glucagon from pancreatic β-cells and α-cells, respectively. Endogenous SST secreted from δ-cells is a paracrine regulator of insulin and glucagon secretion, although the exact physiological significance of this regulation is unclear. Secreted SST binds to specific receptors (SSTRs), which are coupled to Gi/o proteins. In both β- and α-cells, activation of SSTRs suppresses hormone secretion by reducing cAMP levels, inhibiting electrical activity, decreasing Ca²⁺ influx through voltage-gated Ca²⁺ channels and directly reducing exocytosis in a Ca²⁺ and cAMP-independent manner. In rodents, β-cells express predominantly SSTR5, whereas α-cells express SSTR2. In human islets, SSTR2 is the dominant receptor in both β- and α-cells, but other isoforms also contribute to the SST effects. Evidence from rodent models suggests that SST secretion from δ-cells is dysregulated in diabetes mellitus, which may contribute to the metabolic disturbances in this disease. SST analogues are currently used for the treatment of hyperinsulinism and other endocrine disorders, including acromegaly and Cushing's syndrome.
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Affiliation(s)
- Matthias Braun
- Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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17
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Gatto F, Feelders R, van der Pas R, Kros JM, Dogan F, van Koetsveld PM, van der Lelij AJ, Neggers SJCMM, Minuto F, de Herder W, Lamberts SWJ, Ferone D, Hofland LJ. β-Arrestin 1 and 2 and G protein-coupled receptor kinase 2 expression in pituitary adenomas: role in the regulation of response to somatostatin analogue treatment in patients with acromegaly. Endocrinology 2013; 154:4715-25. [PMID: 24169548 DOI: 10.1210/en.2013-1672] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent in vitro studies highlighted G protein-coupled receptor kinase (GRK)2 and β-arrestins as important players in driving somatostatin receptor (SSTR) desensitization and trafficking. Our aim was to characterize GRK2 and β-arrestins expression in different pituitary adenomas and to investigate their potential role in the response to somatostatin analog (SSA) treatment in GH-secreting adenomas (GHomas). We evaluated mRNA expression of multiple SSTRs, GRK2, β-arrestin 1, and β-arrestin 2 in 41 pituitary adenomas (31 GHomas, 6 nonfunctioning [NFPAs], and 4 prolactinomas [PRLomas]). Within the GHomas group, mRNA data were correlated with the in vivo response to an acute octreotide test and with the GH-lowering effect of SSA in cultured primary cells. β-Arrestin 1 expression was low in all 3 adenoma histotypes. However, its expression was significantly lower in GHomas and PRLomas, compared with NFPAs (P < .01). GRK2 expression was higher in PRLomas and NFPAs compared with GHomas (P < .05). In the GHoma group, GRK2 expression was inversely correlated to β-arrestin 1 (P < .05) and positively correlated to β-arrestin 2 (P < .0001). SSA treatment did not affect GRK2 and β-arrestin expression in GHomas or in cultured rat pituitary tumor GH3 cells. Noteworthy, β-arrestin 1 was significantly lower (P < .05) in tumors responsive to octreotide treatment in vitro, whereas GRK2 and SSTR subtype 2 were significantly higher (P < .05). Likewise, β-arrestin 1 levels were inversely correlated with the in vivo response to acute octreotide test (P = .001), whereas GRK2 and SSTR subtype 2 expression were positively correlated (P < .05). In conclusion, for the first time, we characterized GRK2, β-arrestin 1, and β-arrestin 2 expression in a representative number of pituitary adenomas. β-Arrestin 1 and GRK2 seem to have a role in modulating GH secretion during SSA treatment.
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Affiliation(s)
- Federico Gatto
- Erasmus Medical Center, Room Ee 530b, Doctor Molewaterplein 50, 3015 GE Rotterdam, The Netherlands.
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Veenstra MJ, de Herder WW, Feelders RA, Hofland LJ. Targeting the somatostatin receptor in pituitary and neuroendocrine tumors. Expert Opin Ther Targets 2013; 17:1329-43. [DOI: 10.1517/14728222.2013.830711] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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19
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Characteristics of the cellular receptor influence the intracellular fate and efficiency of virus infection. J Virol 2013; 87:5916-25. [PMID: 23514894 DOI: 10.1128/jvi.00398-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The intracellular fate of internalized virus-receptor complexes is suspected of influencing the efficiency of virus infection. However, direct evidence of a link between infection and the fate of internalized virus has been difficult to obtain. To directly address this question, we generated human 293 cell lines stably expressing comparable cell surface levels of three different members of the somatostatin receptor family (SSTR) which have natural differences in intracellular trafficking. Utilizing a glycoprotein that recognizes SSTR, we found that distinctive receptor subtype-specific destinations correlated with observable differences in the level of infection. Infection via SSTR-2 and -3 is restricted at a point after receptor binding and endocytosis but prior to penetration into the host cytoplasm. In contrast, entry via SSTR-5 featured a slower internalization with greater dependence on cholesterol. Quantitative real-time PCR showed that virus bound to SSTR-5 was directed to an intracellular environment that allowed near-wild-type (WT) levels of penetration, possibly due to a more favorable complement of host cell proteases, whereas SSTR-2 and -3 directed virions to a degradative compartment in which cytosol penetration was less efficient. Taken together, the results support that the superior receptor capacity of SSTR-5 results from its internalization into a cellular compartment that is more favorable to the cytoplasmic penetration of viral cores and reverse transcription. They suggest that the intracellular destination of internalized complexes is an important characteristic of a virus receptor and may have exerted a selective pressure on the choice of an entry receptor during evolution of viral glycoproteins.
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Lupp A, Nagel F, Schulz S. Reevaluation of sst₁ somatostatin receptor expression in human normal and neoplastic tissues using the novel rabbit monoclonal antibody UMB-7. ACTA ACUST UNITED AC 2013; 183:1-6. [PMID: 23466804 DOI: 10.1016/j.regpep.2013.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 12/20/2012] [Accepted: 02/13/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND The somatostatin receptor 1 (sst1) is widely distributed throughout the body and is also present in neoplastic tissues. However, little is known about its precise tissue distribution, regulation and function, which may in part be due to the lack of specific monoclonal anti-sst1 antibodies. METHODS We have characterized the novel rabbit monoclonal anti-human sst1 antibody UMB-7 using sst1-expressing cells and human pituitary samples. The antibody was then used for immunohistochemical staining of a large panel of formalin-fixed, paraffin-embedded human tissues. RESULTS Western blot analyses of BON-1 cells and human pituitary revealed a broad band migrating at a molecular weight of 45,000-60,000. After enzymatic deglycosylation the size of this band decreased to a molecular weight of 45,000. UMB-7 yielded an efficient immunostaining of distinct cell populations in the human tissue samples with a predominance of plasma membrane staining, which was completely abolished by preadsorption of UMB-7 with its immunizing peptide. The sst1 receptor was detected in anterior pituitary, pancreatic islets, distal tubules, enteric ganglion cells and nerve fibers, chief cells of the gastric mucosa, macrophages and mast cells. In addition, sst1 was observed in pituitary adenomas, gastrointestinal neuroendocrine tumors and pheochromocytoma as well as in pancreatic adenocarcinomas, gastric carcinomas, urinary bladder carcinomas and sarcomas. CONCLUSIONS UMB-7 may prove of great value in the identification of sst1-expressing tumors during routine histopathological examinations. This may open up new routes for diagnostic and therapeutic intervention.
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Affiliation(s)
- Amelie Lupp
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Germany
| | - Falko Nagel
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Germany
| | - Stefan Schulz
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Germany.
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Albertelli M, Arvigo M, Boschetti M, Ferone D, Gatto F, Minuto F. Somatostatin receptor pathophysiology in the neuroendocrine system. Expert Rev Endocrinol Metab 2013; 8:149-157. [PMID: 30736175 DOI: 10.1586/eem.13.7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The actions of somatostatin (SRIF) are mediated by specific G protein-coupled receptors, named SRIF receptor (SSTR) subtypes 1, 2, 3 and 5. SRIF binding to SSTR activates a series of second messenger systems, resulting in the inhibition of calcium channels and adenylate cyclase activity, ultimately leading to inhibition of hormone secretion, while stimulation of other second messengers, such as phosphotyrosine phosphatases play a role in the control of cell growth. The SSTR and dopamine receptor families share a 30% sequence homology and appear to be structurally related. The knowledge on the pathophysiology of these two families of G protein-coupled receptors in neuroendocrine tumors has progressively increased due to the new insights in receptor dimerization, internalization and trafficking. Depending on the expression of different SSTRs in tissues, their combinations and interactions affect the functionality of the subtypes expressed and the influence of the microenvironment, the response to ligands and, by consequence, the response to treatment can be very different.
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Affiliation(s)
| | - Marica Arvigo
- a Department of Internal Medicine, University of Genova, Genova, Italy
| | - Mara Boschetti
- a Department of Internal Medicine, University of Genova, Genova, Italy
- b IRCSS AOU San Martino - IST, Genova, Italy
| | - Diego Ferone
- a Department of Internal Medicine, University of Genova, Genova, Italy
- b IRCSS AOU San Martino - IST, Genova, Italy
| | - Federico Gatto
- a Department of Internal Medicine, University of Genova, Genova, Italy
| | - Francesco Minuto
- a Department of Internal Medicine, University of Genova, Genova, Italy
- b IRCSS AOU San Martino - IST, Genova, Italy
- c Department of Internal Medicine, University of Genova, Genova, Italy.
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Peptide receptor targeting in cancer: the somatostatin paradigm. INTERNATIONAL JOURNAL OF PEPTIDES 2013; 2013:926295. [PMID: 23476673 PMCID: PMC3582104 DOI: 10.1155/2013/926295] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 12/10/2012] [Accepted: 12/28/2012] [Indexed: 02/06/2023]
Abstract
Peptide receptors involved in pathophysiological processes represent promising therapeutic targets. Neuropeptide somatostatin (SST) is produced by specialized cells in a large number of human organs and tissues. SST primarily acts as inhibitor of endocrine and exocrine secretion via the activation of five G-protein-coupled receptors, named sst1–5, while in central nervous system, SST acts as a neurotransmitter/neuromodulator, regulating locomotory and cognitive functions. Critical points of SST/SST receptor biology, such as signaling pathways of individual receptor subtypes, homo- and heterodimerization, trafficking, and cross-talk with growth factor receptors, have been extensively studied, although functions associated with several pathological conditions, including cancer, are still not completely unraveled. Importantly, SST exerts antiproliferative and antiangiogenic effects on cancer cells in vitro, and on experimental tumors in vivo. Moreover, SST agonists are clinically effective as antitumor agents for pituitary adenomas and gastro-pancreatic neuroendocrine tumors. However, SST receptors being expressed by tumor cells of various tumor histotypes, their pharmacological use is potentially extendible to other cancer types, although to date no significant results have been obtained. In this paper the most recent findings on the expression and functional roles of SST and SST receptors in tumor cells are discussed.
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Abstract
The neuropeptide somatostatin (SRIF) is an important modulator of neurotransmission in the central nervous system and acts as a potent inhibitor of hormone and exocrine secretion. In addition, SRIF regulates cell proliferation in normal and tumorous tissues. The six somatostatin receptor subtypes (sst1, sst2A, sst2B, sst3, sst4, and sst5), which belong to the G protein-coupled receptor (GPCR) family, share a common molecular topology: a hydrophobic core of seven transmembrane-spanning α-helices, three intracellular loops, three extracellular loops, an amino-terminus outside the cell, and a carboxyl-terminus inside the cell. For most of the GPCRs, intracytosolic sequences, and more particularly the C-terminus, are believed to interact with proteins that are mandatory for either exporting neosynthesized receptor, anchoring receptor at the plasma membrane, internalization, recycling, or degradation after ligand binding. Accordingly, most of the SRIF receptors can traffic not only in vitro within different cell types but also in vivo. A picture of the pathways and proteins involved in these processes is beginning to emerge.
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Affiliation(s)
- Zsolt Csaba
- INSERM, Unité Mixte de Recherche U676, Paris, France
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24
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Filice M, Palomo JM. Monosaccharide derivatives as central scaffolds in the synthesis of glycosylated drugs. RSC Adv 2012. [DOI: 10.1039/c2ra00515h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Lupp A, Nagel F, Doll C, Röcken C, Evert M, Mawrin C, Saeger W, Schulz S. Reassessment of sst3 somatostatin receptor expression in human normal and neoplastic tissues using the novel rabbit monoclonal antibody UMB-5. Neuroendocrinology 2012; 96:301-10. [PMID: 22414742 DOI: 10.1159/000337659] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 02/28/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND Among the five somatostatin receptors (sst(1)-sst(5)), the sst(3) receptor displays a distinct pharmacological profile. Like sst(2), the sst(3) receptor efficiently internalizes radiolabeled somatostatin analogs. Unlike sst(2), however, internalized sst(3) receptors are rapidly transferred to lysosomes for degradation. Apart from this, very little is known about the clinical relevance of the sst(3) receptor, which may in part be due to the lack of specific monoclonal sst(3) antibodies. METHODS Here, we have extensively characterized the novel rabbit monoclonal anti-human sst(3) antibody UMB-5 using transfected cells and receptor-expressing tissues. UMB-5 was then subjected to immunohistochemical staining of a series of 190 formalin-fixed, paraffin-embedded normal and neoplastic human tissues. RESULTS Specificity of UMB-5 was demonstrated by detection of a broad band migrating at a molecular weight of 70,000-85,000 in immunoblots from human pituitary. After enzymatic deglycosylation, the size of this band decreased to a molecular weight of 45,000. Tissue immunostaining was completely abolished by pre-adsorption of UMB-5 with its immunizing peptide. In addition, UMB-5 detected distinct cell populations in human tissues like pancreatic islands, anterior pituitary, adrenal cortex, adrenal medulla, and enteric ganglia, similar to that seen with a rabbit polyclonal antibody generated against a different carboxyl-terminal epitope of the sst(3) receptor. In a comparative immunohistochemical study, UMB-5 yielded predominant plasma membrane staining in the majority of pituitary adenomas, pheochromocytomas, and a subset of neuroendocrine tumors. The sst(3) receptor was also present in many glioblastomas, pancreatic, breast, cervix, and ovarian carcinomas. CONCLUSION The rabbit monoclonal antibody UMB-5 may prove of great value in the identification of sst(3)-expressing tumors during routine histopathological examinations. Given its unique trafficking properties, these tumors may be potential candidates for sst(3)-directed receptor radiotherapy.
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Affiliation(s)
- Amelie Lupp
- Department of Pharmacology and Toxicology, University Hospital, Friedrich Schiller University Jena, Jena, Germany
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26
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Córdoba-Chacón J, Gahete MD, Castaño JP, Kineman RD, Luque RM. Homologous and heterologous in vitro regulation of pituitary receptors for somatostatin, growth hormone (GH)-releasing hormone, and ghrelin in a nonhuman primate (Papio anubis). Endocrinology 2012; 153:264-72. [PMID: 22109886 PMCID: PMC3249678 DOI: 10.1210/en.2011-1677] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Secretion of GH by pituitary somatotrophs is primarily stimulated by GHRH and ghrelin and inhibited by somatostatin through the activation of specific receptors [GHRH receptor (GHRH-R), GH secretagogue receptor (GHS-R) and somatostatin receptors (sst1-5), respectively]. However, we have shown that somatostatin, at low doses, can also stimulate GH release, directly and specifically, in primary pituitary cultures from a nonhuman primate (baboons, Papio anubis) and pigs. To determine whether somatostatin, GHRH, and ghrelin can also regulate the expression of their receptors in primates, pituitary cultures from baboons were treated for 4 h with GHRH or ghrelin (10(-8) m) or with high (10(-7) m) and low (10(-15) m) doses of somatostatin, and GH release and expression levels of all receptors were measured. GHRH/ghrelin decreased the expression of their respective receptors (GHRH-R and GHS-R). Both peptides increased sst1, only GHRH decreased sst5 expression, whereas sst2 expression remained unchanged. The effects of GHRH/ghrelin were completely mimicked by forskolin (adenylate cyclase activator) and phorbol 12-myristate 13-acetate (protein kinase C activator), respectively, indicating the regulation of receptor subtype levels by GHRH and ghrelin involved distinct signaling pathways. In contrast, high-dose somatostatin did not alter GH release but increased sst1, sst2, and sst5 expression, whereas GHRH-R and GHS-R expression were unaffected. Interestingly, low-dose somatostatin increased GH release and sst1 mRNA but decreased sst5 and GHRH-R expression, similar to that observed for GHRH. Altogether, our data show for the first time in a primate model that the primary regulators of somatotroph function (GHRH/ghrelin/somatostatin) exert both homologous and heterologous regulation of receptor synthesis which is dose and subtype dependent and involves distinct signaling pathways.
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MESH Headings
- Animals
- Cells, Cultured
- Colforsin/pharmacology
- Gene Expression/drug effects
- Ghrelin/administration & dosage
- Growth Hormone-Releasing Hormone/administration & dosage
- In Vitro Techniques
- Papio anubis/genetics
- Papio anubis/metabolism
- Pituitary Gland/drug effects
- Pituitary Gland/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Ghrelin/genetics
- Receptors, Ghrelin/metabolism
- Receptors, LHRH/genetics
- Receptors, LHRH/metabolism
- Receptors, Somatostatin/agonists
- Receptors, Somatostatin/genetics
- Receptors, Somatostatin/metabolism
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Somatostatin/administration & dosage
- Swine
- Tetradecanoylphorbol Acetate/pharmacology
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Affiliation(s)
- Jose Córdoba-Chacón
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, E-14014 Córdoba, Spain
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Abstract
Somatostatin (SS) and dopamine (DA) receptors have been highlighted as two critical regulators in the negative control of hormonal secretion in a wide group of human endocrine tumors. Both families of receptors belong to the superfamily of G protein-coupled receptors and share a number of structural and functional characteristics. Because of the generally reported high expression of somatostatin receptors (SSTRs) in neuroendocrine tumors (NET), somatostatin analogs (SSA) have a pronounced role in the medical therapy for this class of tumors, especially pituitary adenomas and well-differentiated gastroenteropancreatic NET (GEP NET). Moreover, NET express not only SSTR but also frequently dopamine receptors (DRs), and DA agonists targeting the D(2) receptor (D(2)) have been demonstrated to be effective in controlling hormone secretion and cell proliferation in in vivo and in vitro studies. The treatment with SSAs combined with DA agonists has already been demonstrated efficacious in a subgroup of patients with GH-secreting pituitary adenomas and few reported cases of carcinoids. The recent availability of new selective and universal SSA and DA agonists, as well as the chimeric SS/DA compounds, may shed new light on the potential role of SSTR and D(2) as combined targets for biotherapy in NET. This review provides an overview of the latest studies evaluating the expression of SSTR and DR in NET, focusing on their co-expression and the possible clinical implications of such co-expression. Moreover, the most recent insights in SSTR and D(2) pathophysiology and the future perspectives for treatment with SSA, DA agonists, and SS/DA chimeric compounds are discussed.
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Affiliation(s)
- Federico Gatto
- Division of Endocrinology, Department of Internal Medicine, Erasmus Medical Center, Room Ee530b, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
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Moncayo R. Reflections on the theory of "silver bullet" octreotide tracers: implications for ligand-receptor interactions in the age of peptides, heterodimers, receptor mosaics, truncated receptors, and multifractal analysis. EJNMMI Res 2011; 1:9. [PMID: 22214590 PMCID: PMC3251005 DOI: 10.1186/2191-219x-1-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 07/26/2011] [Indexed: 12/25/2022] Open
Abstract
The classical attitude of Nuclear Medicine practitioners on matters of peptide-receptor interactions has maintained an intrinsic monogamic character since many years. New advances in the field of biochemistry and even in clinical Nuclear Medicine have challenged this type of thinking, which prompted me to work on this review. The central issue of this paper will be the use of somatostatin analogs, i.e., octreotide, in clinical imaging procedures as well as in relation to neuroendocirne tumors. Newly described characteristics of G-protein coupled receptors such as the formation of receptor mosaics will be discussed. A small section will enumerate the regulatory processes found in the cell membrane. Possible new interpretations, other than tumor detection, based on imaging procedures with somatostatin analogs will be presented. The readers will be taken to situations such as inflammation, nociception, mechanosensing, chemosensing, fibrosis, taste, and vascularity where somatostatin is involved. Thyroid-associated orbitopathy will be used as a model for the development of multi-agent therapeutics. The final graphical summary depicts the multifactorial properties of ligand binding.
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Affiliation(s)
- Roy Moncayo
- Department of Nuclear Medicine, Medical University of Innsbruck, Innsbruck, Austria.
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29
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Cakir M, Dworakowska D, Grossman A. Somatostatin receptor biology in neuroendocrine and pituitary tumours: part 1--molecular pathways. J Cell Mol Med 2011; 14:2570-84. [PMID: 20629989 PMCID: PMC4373477 DOI: 10.1111/j.1582-4934.2010.01125.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Neuroendocrine tumours (NETs) may occur at many sites in the body although the majority occur within the gastroenteropancreatic axis. Non-gastroenteropancreatic NETs encompass phaeochromocytomas and paragangliomas, medullary thyroid carcinoma, anterior pituitary tumour, broncho-pulmonary NETs and parathyroid tumours. Like most endocrine tumours, NETs also express somatostatin (SST) receptors (subtypes 1–5) whose ligand SST is known to inhibit endocrine and exocrine secretions and have anti-tumour effects. In the light of this knowledge, the idea of using SST analogues in the treatment of NETs has become increasingly popular and new studies have centred upon the development of new SST analogues. We attempt to review SST receptor (SSTR) biology primarily in neuroendocrine tissues, focusing on pituitary tumours. A full data search was performed through PubMed over the years 2000–2009 with keywords ‘somatostatin, molecular biology, somatostatin receptors, somatostatin signalling, NET, pituitary’ and all relevant publications have been included, together with selected publications prior to that date. SSTR signalling in non-neuroendocrine solid tumours is beyond the scope of this review. SST is a potent anti-proliferative and anti-secretory agent for some NETs. The successful therapeutic use of SST analogues in the treatment of these tumours depends on a thorough understanding of the diverse effects of SSTR subtypes in different tissues and cell types. Further studies will focus on critical points of SSTR biology such as homo- and heterodimerization of SSTRs and the differences between post-receptor signalling pathways of SSTR subtypes.
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Affiliation(s)
- Mehtap Cakir
- Selcuk University, Meram School of Medicine, Division of Endocrinology and Metabolism, Konya, Turkey.
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30
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Shishkin SS, Lisitskaya KV, Krakhmaleva IN. Biochemical polymorphism of the growth hormone system proteins and its manifestations in human prostate cells. BIOCHEMISTRY (MOSCOW) 2011; 75:1547-62. [PMID: 21417994 DOI: 10.1134/s0006297910130043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The basic mechanisms are considered that are responsible for producing biochemical polymorphism of human proteins realized at three basic levels: the structures of genome and genes; the transcription and maturation of transcripts; the postsynthetic formation of functionally active protein products of gene expression. The data on biochemical polymorphism of growth hormone (GH) and some other proteins that are directly or indirectly necessary for its functioning and support this polymorphism by polylocus, polyallelism, alternative splicing, and various postsynthetic modifications are analyzed. The role of polymorphic proteins of the GH system is discussed in formation of a variety of oligomeric molecular structures of this system (multicomponent transport complexes, receptors, and endocellular protein ensembles involved in the regulation of gene expression). It is emphasized that such structural polymorphism significantly influences the biological effects in various parts of the GH system during physiological processes and in tumors, in particular in prostate cancer.
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Affiliation(s)
- S S Shishkin
- Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia.
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31
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Robertson CR, Flynn SP, White HS, Bulaj G. Anticonvulsant neuropeptides as drug leads for neurological diseases. Nat Prod Rep 2011; 28:741-62. [PMID: 21340067 DOI: 10.1039/c0np00048e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Anticonvulsant neuropeptides are best known for their ability to suppress seizures and modulate pain pathways. Galanin, neuropeptide Y, somatostatin, neurotensin, dynorphin, among others, have been validated as potential first-in-class anti-epileptic or/and analgesic compounds in animal models of epilepsy and pain, but their therapeutic potential extends to other neurological indications, including neurodegenerative and psychatric disorders. Disease-modifying properties of neuropeptides make them even more attractive templates for developing new-generation neurotherapeutics. Arguably, efforts to transform this class of neuropeptides into drugs have been limited compared to those for other bioactive peptides. Key challenges in developing neuropeptide-based anticonvulsants are: to engineer optimal receptor-subtype selectivity, to improve metabolic stability and to enhance their bioavailability, including penetration across the blood–brain barrier (BBB). Here, we summarize advances toward developing systemically active and CNS-penetrant neuropeptide analogs. Two main objectives of this review are: (1) to provide an overview of structural and pharmacological properties for selected anticonvulsant neuropeptides and their analogs and (2) to encourage broader efforts to convert these endogenous natural products into drug leads for pain, epilepsy and other neurological diseases.
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Affiliation(s)
- Charles R Robertson
- College of Pharmacy, Department of Medicinal Chemistry, 421 Wakara Way, STE. 360 Salt Lake City, UT 84108, USA
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32
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Kukwa W, Andrysiak R, Kukwa A, Hubalewska-Dydejczyk A, Gronkiewicz Z, Wojtowicz P, Krolicki L, Wierzchowski W, Grochowski T, Czarnecka AM. 99mTC-octreotide scintigraphy and somatostatin receptor subtype expression in juvenile nasopharyngeal angiofibromas. Head Neck 2011; 33:1739-46. [DOI: 10.1002/hed.21668] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 09/02/2010] [Accepted: 10/04/2010] [Indexed: 11/08/2022] Open
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33
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Liu EH, Oberg K. The history and development of the gastroenteropancreatic endocrine axis. Endocrinol Metab Clin North Am 2010; 39:697-711. [PMID: 21095539 DOI: 10.1016/j.ecl.2010.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fundamental medical principles, such as hormone action, distant physiologic regulation, and ductless secretion were once mysteries. They now form the basis of basic medical diagnostics and therapeutics. This article discusses and reviews the rich history that served as the foundation of modern medicine, from the early descriptions of tumors, to the discovery of hormones and assays, and how they resulted in the treatments available today.
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Affiliation(s)
- Eric H Liu
- Department of Surgery, Surgical Oncology, Vanderbilt University, Medical Center, Nashville, TN, USA
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Abbenante G, Becker B, Blanc S, Clark C, Condie G, Fraser G, Grathwohl M, Halliday J, Henderson S, Lam A, Liu L, Mann M, Muldoon C, Pearson A, Premraj R, Ramsdale T, Rossetti T, Schafer K, Le Thanh G, Tometzki G, Vari F, Verquin G, Waanders J, West M, Wimmer N, Yau A, Zuegg J, Meutermans W. Biological Diversity from a Structurally Diverse Library: Systematically Scanning Conformational Space Using a Pyranose Scaffold. J Med Chem 2010; 53:5576-86. [DOI: 10.1021/jm1002777] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | - Bernd Becker
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | | | - Chris Clark
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Glenn Condie
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | | | | | - Judy Halliday
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | | | - Ann Lam
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Ligong Liu
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Maretta Mann
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Craig Muldoon
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Andrew Pearson
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | | | | | - Tony Rossetti
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Karl Schafer
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Giang Le Thanh
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | | | - Frank Vari
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | | | | | - Michael West
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Norbert Wimmer
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Annika Yau
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Johannes Zuegg
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
| | - Wim Meutermans
- Alchemia Ltd, Eight Mile Plains, Queensland 4113, Australia
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Ovadia O, Greenberg S, Laufer B, Gilon C, Hoffman A, Kessler H. Improvement of drug-like properties of peptides: the somatostatin paradigm. Expert Opin Drug Discov 2010; 5:655-71. [DOI: 10.1517/17460441.2010.493935] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Córdoba-Chacón J, Gahete MD, Duran-Prado M, Pozo-Salas AI, Malagón MM, Gracia-Navarro F, Kineman RD, Luque RM, Castaño JP. Identification and characterization of new functional truncated variants of somatostatin receptor subtype 5 in rodents. Cell Mol Life Sci 2010; 67:1147-63. [PMID: 20063038 PMCID: PMC11115927 DOI: 10.1007/s00018-009-0240-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 12/08/2009] [Accepted: 12/18/2009] [Indexed: 12/11/2022]
Abstract
Somatostatin and cortistatin exert multiple biological actions through five receptors (sst1-5); however, not all their effects can be explained by activation of sst1-5. Indeed, we recently identified novel truncated but functional human sst5-variants, present in normal and tumoral tissues. In this study, we identified and characterized three novel truncated sst5 variants in mice and one in rats displaying different numbers of transmembrane-domains [TMD; sst5TMD4, sst5TMD2, sst5TMD1 (mouse-variants) and sst5TMD1 (rat-variant)]. These sst5 variants: (1) are functional to mediate ligand-selective-induced variations in [Ca(2+)]i and cAMP despite being truncated; (2) display preferential intracellular distribution; (3) mostly share full-length sst5 tissue distribution, but exhibit unique differences; (4) are differentially regulated by changes in hormonal/metabolic environment in a tissue- (e.g., central vs. systemic) and ligand-dependent manner. Altogether, our results demonstrate the existence of new truncated sst5-variants with unique ligand-selective signaling properties, which could contribute to further understanding the complex, distinct pathophysiological roles of somatostatin and cortistatin.
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Affiliation(s)
- Jose Córdoba-Chacón
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Edificio Severo Ochoa. Planta 3. Campus de Rabanales, 14014 Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
| | - Manuel D. Gahete
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Edificio Severo Ochoa. Planta 3. Campus de Rabanales, 14014 Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
| | - Mario Duran-Prado
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Edificio Severo Ochoa. Planta 3. Campus de Rabanales, 14014 Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
| | - Ana I. Pozo-Salas
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Edificio Severo Ochoa. Planta 3. Campus de Rabanales, 14014 Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
| | - María M. Malagón
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Edificio Severo Ochoa. Planta 3. Campus de Rabanales, 14014 Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
| | - F. Gracia-Navarro
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Edificio Severo Ochoa. Planta 3. Campus de Rabanales, 14014 Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
| | - Rhonda D. Kineman
- Research and Development Division, Jesse Brown Veterans Affairs Medical Center, Chicago, IL USA
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL USA
| | - Raul M. Luque
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Edificio Severo Ochoa. Planta 3. Campus de Rabanales, 14014 Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
| | - Justo P. Castaño
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Edificio Severo Ochoa. Planta 3. Campus de Rabanales, 14014 Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn 06/03), Córdoba, Spain
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Hanson A, Poudyal D, Hagemeister A, Reindl KM, Sheridan MA. The ERK and PI3K signaling pathways mediate inhibition of insulin-like growth factor-1 receptor mRNA expression by somatostatin. Mol Cell Endocrinol 2010; 315:57-62. [PMID: 19815052 DOI: 10.1016/j.mce.2009.09.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 09/28/2009] [Accepted: 09/30/2009] [Indexed: 01/11/2023]
Abstract
Somatostatins (SSs) are a structurally diverse family of peptide hormones that regulate various aspects of growth, development, and metabolism in vertebrates. Previously, we showed that SSs inhibit mRNA and functional expression of insulin-like growth factor-1 receptors (IGFR1) in gill filaments of rainbow trout. In this study, we used trout gill filaments, which express in high abundance two distinct IGFR1s, IGFR1A and IGFR1B, to examine the mechanism(s) through which SSs exert their inhibitory effects on IGFR1 expression. SS-14, a predominat SS isoform, directly stimulated the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (Akt), a downstream target of phosphatidylinositol 3-kinase (PI3K), in filaments incubated in vitro. Activation of ERK and Akt by SS-14 was rapid, occuring within 5-10 min, and was concentration-dependent. The ERK pathway inhibitor, U0126, retarded SS-14-stimulated phosphorylation of ERK 1/2, whereas the PI3K inhibitor, LY294002, blocked SS-14-stimulated phosphorylation of Akt. SS-14-inhibited expression of IGFR1 mRNAs was blocked by both U0126 and LY294002. These data indicate that SS-14 inhibition of IGFR1 mRNA expression is mediated through the ERK and PI3K/Akt signaling pathways.
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Affiliation(s)
- Andrea Hanson
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58108-6050, USA
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Martino MCD, Hofland LJ, Lamberts SW. Somatostatin and Somatostatin Receptors: from Basic Concepts to Clinical Applications. PROGRESS IN BRAIN RESEARCH 2010; 182:255-80. [DOI: 10.1016/s0079-6123(10)82011-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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The gastrointestinal tract as an endocrine/neuroendocrine/paracrine organ: organization, chemical messengers and physiological targets. FISH PHYSIOLOGY 2010. [DOI: 10.1016/s1546-5098(10)03007-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Cervia D, Martini D, Ristori C, Catalani E, Timperio AM, Bagnoli P, Casini G. Modulation of the neuronal response to ischaemia by somatostatin analogues in wild-type and knock-out mouse retinas. J Neurochem 2008; 106:2224-35. [PMID: 18624922 DOI: 10.1111/j.1471-4159.2008.05556.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Somatostatin acts at five G protein-coupled receptors, sst(1)-sst(5). In mouse ischaemic retinas, the over-expression of sst(2) (as in sst(1) knock-out mice) results in the reduction of cell death and glutamate release. In this study, we reported that, in wild-type retinas, somatostatin, the multireceptor ligand pasireotide and the sst(2) agonist octreotide decreased ischaemia-induced cell death and that octreotide also decreased glutamate release. In contrast, cell death was increased by blocking sst(2) with cyanamide. In sst(2) over-expressing ischaemic retinas, somatostatin analogues increased cell death, and octreotide also increased glutamate release. To explain this reversal of the anti-ischaemic effect of somatostatin agonists in the presence of sst(2) over-expression, we tested sst(2) desensitisation because of internalisation or altered receptor function. We observed that (i) sst(2) was not internalised, (ii) among G protein-coupled receptor kinases (GRKs) and regulators of G protein signalling (RGSs), GRK1 and RGS1 expression increased following ischaemia, (iii) both GRK1 and RGS1 were down-regulated by octreotide in wild-type ischaemic retinas, (iv) octreotide down-regulated GRK1 but not RGS1 in sst(2) over-expressing ischaemic retinas. These results demonstrate that sst(2) activation protects against retinal ischaemia. However, in the presence of sst(2) over-expression sst(2) is functionally desensitised by agonists, possibly because of sustained RGS1 levels.
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Affiliation(s)
- Davide Cervia
- Department of Environmental Sciences, University of Tuscia, Largo dell'Università snc, Viterbo.
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Cervia D, Casini G, Bagnoli P. Physiology and pathology of somatostatin in the mammalian retina: a current view. Mol Cell Endocrinol 2008; 286:112-22. [PMID: 18242820 DOI: 10.1016/j.mce.2007.12.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 10/11/2007] [Accepted: 12/12/2007] [Indexed: 12/30/2022]
Abstract
In the retina, peptidergic signalling participates in multiple circuits of visual information processing. The neuropeptide somatostatin (SRIF) is localised to amacrine cells and, in some instances, in a subset of ganglion cells. The variegated expression patterns of SRIF receptors (sst(1)-sst(5)) and the variety of signalling mechanisms activated by retinal SRIF suggest that this peptide may exert multiple actions on retinal neurons and on retinal physiology, although our current understanding reflects a rather complicated picture. SRIF, mostly through sst(2), may act as a positive factor in the retina by regulating retinal homeostasis and protecting neurons against damage. In this respect, SRIF analogues seem to constitute a promising therapeutic arsenal to cure different retinal diseases, as for instance, ischemic and diabetic retinopathies. However, further investigations are needed not only to fully understand the functional role of the SRIF system in the retina but also to exploit new chemical space for drug-like molecules.
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Affiliation(s)
- Davide Cervia
- Department of Environmental Sciences, University of Tuscia, Viterbo, Italy
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Erchegyi J, Grace CRR, Samant M, Cescato R, Piccand V, Riek R, Reubi JC, Rivier JE. Ring size of somatostatin analogues (ODT-8) modulates receptor selectivity and binding affinity. J Med Chem 2008; 51:2668-75. [PMID: 18410084 PMCID: PMC2782568 DOI: 10.1021/jm701444y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The synthesis, biological testing, and NMR studies of several analogues of H-c[Cys (3)-Phe (6)-Phe (7)-DTrp (8)-Lys (9)-Thr (10)-Phe (11)-Cys (14)]-OH (ODT-8, a pan-somatostatin analogue, 1) have been performed to assess the effect of changing the stereochemistry and the number of atoms in the disulfide bridge on binding affinity. Cysteine at positions 3 and/or 14 (somatostatin numbering) were/was substituted with d-cysteine, norcysteine, D-norcysteine, homocysteine, and/or D-homocysteine. The 3D structure analysis of selected partially selective, bioactive analogues (3, 18, 19, and 21) was carried out in dimethylsulfoxide. Interestingly and not unexpectedly, the 3D structures of these analogues comprised the pharmacophore for which the analogues had the highest binding affinities (i.e., sst 4 in all cases).
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Affiliation(s)
- Judit Erchegyi
- The Clayton Foundation Laboratories for Peptide Biology and Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA
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Abstract
Any process interfering with dopamine synthesis, its transport to the pituitary gland, or its action at the level of lactotroph dopamine receptors can cause hyperprolactinemia. As described in this article, considering the complexity of prolactin regulation, many factors could cause hyperprolactinemia, and hyperprolactinemia can have clinical effects not only on the reproductive axis. Once any drug effects are excluded, prolactinomas are the most common cause of hyperprolactinemia. The most frequent symptom is hypogonadism in both genders. Medical and surgical therapies generally have excellent results, and most prolactinomas are well controlled or even cured in some cases.
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Affiliation(s)
- Tatiana Mancini
- Internal Medicine, San Marino Hospital, 47899, Republic of San Marino
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Cervia D, Bagnoli P. An update on somatostatin receptor signaling in native systems and new insights on their pathophysiology. Pharmacol Ther 2007; 116:322-41. [PMID: 17719647 DOI: 10.1016/j.pharmthera.2007.06.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 06/28/2007] [Indexed: 12/20/2022]
Abstract
The peptide somatostatin (SRIF) has important physiological effects, mostly inhibitory, which have formed the basis for the clinical use of SRIF compounds. SRIF binding to its 5 guanine nucleotide-binding proteins-coupled receptors leads to the modulation of multiple transduction pathways. However, our current understanding of signaling exerted by receptors endogenously expressed in different cells/tissues reflects a rather complicated picture. On the other hand, the complexity of SRIF receptor signaling in pathologies, including pituitary and nervous system diseases, may be studied not only as alternative intervention points for the modulation of SRIF function but also to exploit new chemical space for drug-like molecules.
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Affiliation(s)
- Davide Cervia
- Department of Environmental Sciences, University of Tuscia, largo dell'Università snc, blocco D, 01100 Viterbo, Italy.
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