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Di Muro G, Catalano R, Treppiedi D, Barbieri AM, Mangili F, Marra G, Di Bari S, Esposito E, Nozza E, Lania AG, Ferrante E, Locatelli M, Modena D, Steinkuhler C, Peverelli E, Mantovani G. The Novel SSTR3 Agonist ITF2984 Exerts Antimitotic and Proapoptotic Effects in Human Non-Functioning Pituitary Neuroendocrine Tumor (NF-PitNET) Cells. Int J Mol Sci 2024; 25:3606. [PMID: 38612419 PMCID: PMC11011875 DOI: 10.3390/ijms25073606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024] Open
Abstract
Somatostatin receptor ligands (SRLs) with high affinity for somatostatin receptors 2 and 5 (SSTR2 and SSTR5) are poorly efficacious in NF-PitNETs, expressing high levels of SSTR3. ITF2984 is a pan-SSTR ligand with high affinity for SSTR3, able to induce SSTR3 activation and to exert antitumoral activity in the MENX rat model. The aim of this study was to test ITF2984's antiproliferative and proapoptotic effects in NF-PitNET primary cultured cells derived from surgically removed human tumors and to characterize their SSTR expression profile. We treated cells derived from 23 NF-PitNETs with ITF2984, and a subset of them with octreotide, pasireotide (SRLs with high affinity for SSTR2 or 5, respectively), or cabergoline (DRD2 agonist) and we measured cell proliferation and apoptosis. SSTR3, SSTR2, and SSTR5 expression in tumor tissues was analyzed by qRT-PCR and Western blot. We demonstrated that ITF2984 reduced cell proliferation (-40.8 (17.08)%, p < 0.001 vs. basal, n = 19 NF-PitNETs) and increased cell apoptosis (+41.4 (22.1)%, p < 0.001 vs. basal, n = 17 NF-PitNETs) in all tumors tested, whereas the other drugs were only effective in some tumors. In our model, SSTR3 expression levels did not correlate with ITF2984 antiproliferative nor proapoptotic effects. In conclusion, our data support a possible use of ITF2984 in the pharmacological treatment of NF-PitNET.
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Affiliation(s)
- Genesio Di Muro
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
- Department of Experimental Medicine, University Sapienza of Rome, 00100 Rome, Italy
| | - Rosa Catalano
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
| | - Donatella Treppiedi
- Endocrinology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (D.T.); (F.M.); (E.F.)
| | - Anna Maria Barbieri
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
| | - Federica Mangili
- Endocrinology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (D.T.); (F.M.); (E.F.)
| | - Giusy Marra
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
| | - Sonia Di Bari
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
| | - Emanuela Esposito
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
- PhD Program in Experimental Medicine, University of Milan, 20100 Milan, Italy
| | - Emma Nozza
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
- PhD Program in Experimental Medicine, University of Milan, 20100 Milan, Italy
| | - Andrea G. Lania
- Department of Biomedical Sciences, Humanitas University, 20090 Pieve Emanuele, Italy;
- Endocrinology and Diabetology Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Humanitas Research Hospital, 20089 Rozzano, Italy
| | - Emanuele Ferrante
- Endocrinology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (D.T.); (F.M.); (E.F.)
| | - Marco Locatelli
- Neurosurgery Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy;
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
| | - Daniela Modena
- Preclinical R&D, Italfarmaco Group, Cinisello Balsamo, 20092 Milan, Italy; (D.M.)
| | | | - Erika Peverelli
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
- Endocrinology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (D.T.); (F.M.); (E.F.)
| | - Giovanna Mantovani
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy; (G.D.M.); (R.C.); (A.M.B.); (G.M.); (S.D.B.); (E.E.); (E.N.)
- Endocrinology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (D.T.); (F.M.); (E.F.)
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2
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Kumar U. Somatostatin and Somatostatin Receptors in Tumour Biology. Int J Mol Sci 2023; 25:436. [PMID: 38203605 PMCID: PMC10779198 DOI: 10.3390/ijms25010436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/24/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
Somatostatin (SST), a growth hormone inhibitory peptide, is expressed in endocrine and non-endocrine tissues, immune cells and the central nervous system (CNS). Post-release from secretory or immune cells, the first most appreciated role that SST exhibits is the antiproliferative effect in target tissue that served as a potential therapeutic intervention in various tumours of different origins. The SST-mediated in vivo and/or in vitro antiproliferative effect in the tumour is considered direct via activation of five different somatostatin receptor subtypes (SSTR1-5), which are well expressed in most tumours and often more than one receptor in a single cell. Second, the indirect effect is associated with the regulation of growth factors. SSTR subtypes are crucial in tumour diagnosis and prognosis. In this review, with the recent development of new SST analogues and receptor-specific agonists with emerging functional consequences of signaling pathways are promising therapeutic avenues in tumours of different origins that are discussed.
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Affiliation(s)
- Ujendra Kumar
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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3
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Oron-Herman M, Kirmayer D, Lupp A, Schulz S, Kostenich G, Afargan M. Expression prevalence and dynamics of GPCR somatostatin receptors 2 and 3 as cancer biomarkers beyond NET: a paired immunohistochemistry approach. Sci Rep 2023; 13:20857. [PMID: 38012197 PMCID: PMC10682014 DOI: 10.1038/s41598-023-47877-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 11/16/2023] [Indexed: 11/29/2023] Open
Abstract
Somatostatin receptors are clinically validated GPCR biomarkers for diagnosis and treatment of various neuroendocrine tumors (NET). Among the five somatostatin receptors, SST2 and SST3 are associated with apoptosis and cell cycle arrest, making these receptor subtypes better differentiated targets in precision oncology. In this study we performed immunohistochemistry of paired tissue microarrays containing 1125 cores, representing 43 tumor types, each stained for SST2 and SST3. A 12-point immunoreactive scoring (IRS) range was used for interpretation of the staining results. We analyzed the results twice, using the conventional positivity IRS cutoffs ≥ 3 and more stringent ≥ 6. Evaluation of receptors expression dynamics was performed for tumor-nodes-metastases (TNM) defined subgroups (ovarian and hepatocellular adenocarcinomas) as a function of their tumor stage. Our results indicate that two-thirds of tested cores exhibit clinically significant expression of at least SST2 or SST3 (IRS ≥ 6). The expression prevalence of both receptors tends to decline with tumor progression. However, an unexpected upregulation of both SST2 and SST3 reemerged in metastases suggesting conserved receptors genetic potential during tumor life cycle. We suggest that SST2 and SST3 should be further explored as potential biomarkers and therapeutic tools for maximizing the efficiency of somatostatin-based precision oncology of solid tumors beyond NET.
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Affiliation(s)
- Mor Oron-Herman
- Starget Pharma, 26 Snir st., 4704086, Ramat Hasharon, Israel.
| | - David Kirmayer
- Starget Pharma, 26 Snir st., 4704086, Ramat Hasharon, Israel
| | - Amelie Lupp
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Drackendorfer Str. 1, 07747, Jena, Germany
| | - Stefan Schulz
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Drackendorfer Str. 1, 07747, Jena, Germany
| | - Genady Kostenich
- Starget Pharma, 26 Snir st., 4704086, Ramat Hasharon, Israel
- The Advanced Technology Center, Sheba Medical Center, Tel Hashomer, 5262000, Ramat Gan, Israel
| | - Michel Afargan
- Starget Pharma, 26 Snir st., 4704086, Ramat Hasharon, Israel
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4
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Oliveira HA, Somvanshi RK, Kumar U. Comparative changes in breast cancer cell proliferation and signalling following somatostatin and cannabidiol treatment. Biochem Biophys Res Commun 2023; 643:30-38. [PMID: 36586156 DOI: 10.1016/j.bbrc.2022.12.073] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/16/2022] [Accepted: 12/23/2022] [Indexed: 12/26/2022]
Abstract
Breast cancer is the most commonly diagnosed cancer and a leading cause of cancer-related death among women worldwide. Somatostatin (SST) and Cannabinoids have an anti-proliferative and pro-apoptotic effect, but the mechanisms of their actions remain elusive. In the present study, we have evaluated the effects of SST, Cannabidiol (CBD) alone or in combination on receptor expression, cell proliferation and apoptosis and related downstream signalling pathways in MDA-MB-231 and MCF-7 breast cancer cells. The results presented here demonstrate the cell type and agonist-dependent changes in receptor expression at the cell membrane, inhibition of cell proliferation and increased apoptosis following treatment with SST and CBD alone and in combination. In comparison to MDA-MB-231 cells, MCF-7 cells treated with SST alone and in combination with CBD exhibited inhibition of phosphorylated Protein Kinase B (pAKT) and phosphorylated-Phosphoinositide 3-Kinase (pPI3K) expression. Importantly, inhibition of PI3K/AKT activation was accompanied by enhanced PTEN expression in MCF-7 cells. These results highlight the possible interaction between SSTR and CBR subtypes with the implication in the modulation of receptor expression, cell viability and signal transduction pathways in a breast cancer cell type-dependent manner.
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Affiliation(s)
- Helen A Oliveira
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Rishi K Somvanshi
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.
| | - Ujendra Kumar
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.
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5
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Wang M, Xu J, Lei XW, Zhang C, Liu SY, Jin LN, Zhang C. Selective Interactions of Mouse Melanocortin Receptor Accessory Proteins with Somatostatin Receptors. Cells 2022; 11:cells11020267. [PMID: 35053382 PMCID: PMC8773839 DOI: 10.3390/cells11020267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/28/2021] [Accepted: 01/06/2022] [Indexed: 02/05/2023] Open
Abstract
Somatostatin receptors (SSTRs) are G protein-coupled receptors (GPCRs) known to regulate exocrine secretion, neurotransmission, and inhibit endogenous cell proliferation. SSTR subtypes (SSTR1-SSTR5) exhibit homo- or heterodimerization with unique signaling characteristics. Melanocortin receptor accessory protein 1 (MRAP1) functions as an allosteric modulator of melanocortin receptors and some other GPCRs. In this study, we investigated the differential interaction of MRAP1 and SSTRs and examined the pharmacological modulation of MRAP1 on mouse SSTR2/SSTR3 and SSTR2/SSTR5 heterodimerization in vitro. Our results show that the mouse SSTR2 forms heterodimers with SSTR3 and SSTR5 and that MRAP1 selectively interacts with SSTR3 and SSTR5 but not SSTR2. The interactive binding sites of SSTR2/SSTR3 or SSTR2/SSTR5 with MRAP1 locate on SSTR3 and SSTR5 but not SSTR2. The binding sites of MRAP1 to SSTR3 are extensive, while the ones of SSTR5 are restricted on transmembrane region six and seven. The heterodimerization of mouse SSTR2, SSTR3, and SSTR5 can be modulated by binding protein in addition to an agonist. Upregulation of extracellular signal-regulated kinases phosphorylation, p27Kip1, and increased cell growth inhibition with the co-expression of SSTR2/SSTR3 or SSTR2/SSTR5 with MRAP1 suggest a regulatory effect of MRAP1 on anti-proliferative response of two SSTR heterodimers. Taken together, these results provide a new insight of MRAP1 on the maintenance and regulation of mouse SSTR dimers which might be helpful to better understand the molecular mechanism involving SSTRs in tumor biology or other human disorders.
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Affiliation(s)
- Meng Wang
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (M.W.); (J.X.); (X.-W.L.)
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China;
| | - Jing Xu
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (M.W.); (J.X.); (X.-W.L.)
| | - Xiao-Wei Lei
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (M.W.); (J.X.); (X.-W.L.)
| | - Cong Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China;
| | - Shang-Yun Liu
- Department of Hematology, Changzheng Hospital, Naval Medical University, Shanghai 200041, China;
| | - Li-Na Jin
- Department of Hematology, Changzheng Hospital, Naval Medical University, Shanghai 200041, China;
- Correspondence: (L.-N.J.); (C.Z.)
| | - Chao Zhang
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (M.W.); (J.X.); (X.-W.L.)
- Correspondence: (L.-N.J.); (C.Z.)
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6
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Gulde S, Wiedemann T, Schillmaier M, Valença I, Lupp A, Steiger K, Yen HY, Bäuerle S, Notni J, Luque R, Schmid H, Schulz S, Ankerst DP, Schilling F, Pellegata NS. Gender-Specific Efficacy Revealed by Head-to-Head Comparison of Pasireotide and Octreotide in a Representative In Vivo Model of Nonfunctioning Pituitary Tumors. Cancers (Basel) 2021; 13:cancers13123097. [PMID: 34205778 PMCID: PMC8235746 DOI: 10.3390/cancers13123097] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/12/2021] [Accepted: 06/16/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary No effective medical therapy exists for residual/recurrent nonfunctioning pituitary tumors (NFPTs). First-generation somatostatin analogs (SSAs) like octreotide targeting somatostatin receptor type 2 (SSTR2) are the mainstay therapy for functioning PTs, but have shown little effect in NFPTs. This is in agreement with an SSTR profile characterized by low SSTR2, and high SSTR3 levels in the latter. Pasireotide a multi-SSTR-preferring SSA, should be effective against NFPTs. To test this hypothesis, we conducted a head-to-head comparison of octreotide and pasireotide in the only spontaneous in vivo model of NFPTs (MENX rats), which recapitulates the human disease. Pasireotide showed a superior anti-tumor effect vs. octreotide, especially in females. Interestingly, Sstr3 levels were higher in female vs. male NFPTs. A sex-related SSTR3 expression may extend to human NFPTs, thereby representing a tool for patient stratification. Our results have translational relevance for the medical treatment of patients with residual/recurrent NFPTs currently lacking efficacious therapeutic options. Abstract Invasive nonfunctioning pituitary tumors (NFPTs) are non-resectable neoplasms associated with frequent relapse and significant comorbidities. Current treatments, including somatostatin receptor 2 (SSTR2)-directed somatostatin analogs (SSAs), often fail against NFPTs. Thus, identifying effective therapies is clinically relevant. As NFPTs express SSTR3 at high levels, pasireotide, a multireceptor-targeted SSA, might be beneficial. Here we evaluated pasireotide in the only representative model of spontaneous NFPTs (MENX rats) in vivo. Octreotide long-acting release (LAR), pasireotide LAR, or placebo, were administered to age-matched, tumor-bearing MENX rats of both sexes for 28 d or 56 d. Longitudinal high-resolution magnetic resonance imaging monitored tumor growth. While tumors in placebo-treated rats increased in volume over time, PTs in drug-treated rats displayed significant growth suppression, and occasional tumor shrinkage. Pasireotide elicited stronger growth inhibition. Radiological responses correlated with tumors’ proliferation rates. Both SSAs, but especially pasireotide, were more effective in female vs. male rats. Basal Sstr3 expression was significantly higher in the former group. It is noteworthy that female human NFPTs patients also have a trend towards higher SSTR3 expression. Altogether, our studies provide the rationale for testing pasireotide in patients with residual/recurrent NFPTs. If confirmed, the sex-related SSTR3 expression might be used as criteria to stratify NFPTs patients for treatment with pasireotide.
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Affiliation(s)
- Sebastian Gulde
- Institute for Diabetes and Cancer, Helmholtz Zentrum München, 85764 Neuherberg, Germany; (S.G.); (T.W.); (I.V.)
- Joint Heidelberg-IDC Translational Diabetes Program, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Tobias Wiedemann
- Institute for Diabetes and Cancer, Helmholtz Zentrum München, 85764 Neuherberg, Germany; (S.G.); (T.W.); (I.V.)
- Joint Heidelberg-IDC Translational Diabetes Program, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Mathias Schillmaier
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, 80333 Munich, Germany; (M.S.); (F.S.)
| | - Isabel Valença
- Institute for Diabetes and Cancer, Helmholtz Zentrum München, 85764 Neuherberg, Germany; (S.G.); (T.W.); (I.V.)
- Joint Heidelberg-IDC Translational Diabetes Program, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Amelie Lupp
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, 07743 Jena, Germany; (A.L.); (S.S.)
| | - Katja Steiger
- Institute of Pathology, School of Medicine, Technical University of Munich, 80333 Munich, Germany; (K.S.); (H.-Y.Y.); (J.N.)
| | - Hsi-Yu Yen
- Institute of Pathology, School of Medicine, Technical University of Munich, 80333 Munich, Germany; (K.S.); (H.-Y.Y.); (J.N.)
| | - Stephen Bäuerle
- Department of Mathematics, Technical University of Munich, 85748 Garching, Germany; (S.B.); (D.P.A.)
| | - Johannes Notni
- Institute of Pathology, School of Medicine, Technical University of Munich, 80333 Munich, Germany; (K.S.); (H.-Y.Y.); (J.N.)
- Experimental Radiopharmacy, Clinic for Nuclear Medicine, University Hospital Essen, 45147 Essen, Germany
| | - Raul Luque
- Department of Cell Biology, Physiology, and Immunology, Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), University of Córdoba and Hospital Universitario Reina Sofía (HURS), 14004 Cordoba, Spain;
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBERobn), 14004 Cordoba, Spain
| | - Herbert Schmid
- Department of Oncology Research, Novartis Institute for BioMedical Research, Novartis Pharma AG, 4033 Basel, Switzerland;
| | - Stefan Schulz
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, 07743 Jena, Germany; (A.L.); (S.S.)
| | - Donna P. Ankerst
- Department of Mathematics, Technical University of Munich, 85748 Garching, Germany; (S.B.); (D.P.A.)
| | - Franz Schilling
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, 80333 Munich, Germany; (M.S.); (F.S.)
| | - Natalia S. Pellegata
- Institute for Diabetes and Cancer, Helmholtz Zentrum München, 85764 Neuherberg, Germany; (S.G.); (T.W.); (I.V.)
- Joint Heidelberg-IDC Translational Diabetes Program, Heidelberg University Hospital, 69120 Heidelberg, Germany
- Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy
- Correspondence: ; Tel.: +49-089-3187263; Fax: +49-089-31873360
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7
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Giardino E, Catalano R, Mangili F, Barbieri AM, Treppiedi D, Elli FM, Dolci A, Contarino A, Spada A, Arosio M, Mantovani G, Peverelli E. Octreotide and pasireotide effects on medullary thyroid carcinoma (MTC) cells growth, migration and invasion. Mol Cell Endocrinol 2021; 520:111092. [PMID: 33248230 DOI: 10.1016/j.mce.2020.111092] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 11/18/2020] [Accepted: 11/21/2020] [Indexed: 12/17/2022]
Abstract
Medullary thyroid carcinoma (MTC) is a rare neuroendocrine neoplasm of the parafollicular thyroid C cells. Although somatostatin receptors are expressed by MTCs, treatment with octreotide has shown poor efficacy, whereas recently pasireotide has demonstrated antiproliferative effects in persistent postoperative MTCs. Aim of this study was to test the effects of octreotide and pasireotide on MTC cells proliferation, cell cycle proteins expression, MAPK activation, apoptosis, calcitonin secretion, migration and invasion in TT cell line as well as in primary MTC cultured cells. Our results showed that both octreotide and pasireotide reduced TT cell proliferation (-35.2 ± 12.1%, p < 0.001, and -25.3 ± 24.8%, p < 0.05, at 10-8 M, respectively), with concomitant inhibition of ERK phosphorylation and cyclin D1 expression. This cytostatic effect was accompanied by a proapoptotic action, with an increase of caspase3/7 activity of 1.5-fold. Moreover, both octreotide and pasireotide inhibited cell migration (-50.9 ± 11.3%, p < 0.01, and -40.5 ± 17%, p < 0.05, respectively) and invasion (-61.3 ± 35.1%, p < 0.05, and -49.7 ± 18%, p < 0.01, respectively). No effect was observed on calcitonin secretion. We then tried to extend these observations to primary cultures (n = 5). Octreotide and/or pasireotide were effective in reducing cells proliferation in 3 out of 5 tumors, and to induce cell apoptosis in 1 out of 3 MTCs. Both octreotide and pasireotide were able to reduce cell migration in all MTC tested. SST2, SST3 and SST5 were expressed in all MTC, with a tendency to increased expression of SST2 in RET mutated vs wild type MTCs. In agreement, inhibition of mutated RET in TT cells reduced SST2 expression. In conclusion, we demonstrated that octreotide and pasireotide inhibited cell proliferation and invasiveness in a subset of MTC, supporting their potential use in the control of tumor growth.
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Affiliation(s)
- E Giardino
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - R Catalano
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy; PhD Program in Endocrinological Sciences, Sapienza University of Rome, Rome, Italy
| | - F Mangili
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - A M Barbieri
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - D Treppiedi
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - F M Elli
- Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan, Italy
| | - A Dolci
- Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan, Italy
| | - A Contarino
- Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan, Italy
| | - A Spada
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - M Arosio
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy; Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan, Italy
| | - G Mantovani
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy; Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan, Italy.
| | - E Peverelli
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
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8
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Paik S, Somvanshi RK, Oliveira HA, Zou S, Kumar U. Somatostatin Ameliorates β-Amyloid-Induced Cytotoxicity via the Regulation of CRMP2 Phosphorylation and Calcium Homeostasis in SH-SY5Y Cells. Biomedicines 2021; 9:biomedicines9010027. [PMID: 33401710 PMCID: PMC7823260 DOI: 10.3390/biomedicines9010027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/24/2020] [Accepted: 12/25/2020] [Indexed: 11/17/2022] Open
Abstract
Somatostatin is involved in the regulation of multiple signaling pathways and affords neuroprotection in response to neurotoxins. In the present study, we investigated the role of Somatostatin-14 (SST) in cell viability and the regulation of phosphorylation of Collapsin Response Mediator Protein 2 (CRMP2) (Ser522) via the blockade of Ca2+ accumulation, along with the inhibition of cyclin-dependent kinase 5 (CDK5) and Calpain activation in differentiated SH-SY5Y cells. Cell Viability and Caspase 3/7 assays suggest that the presence of SST ameliorates mitochondrial stability and cell survival pathways while augmenting pro-apoptotic pathways activated by Aβ. SST inhibits the phosphorylation of CRMP2 at Ser522 site, which is primarily activated by CDK5. Furthermore, SST effectively regulates Ca2+ influx in the presence of Aβ, directly affecting the activity of calpain in differentiated SH-SY5Y cells. We also demonstrated that SSTR2 mediates the protective effects of SST. In conclusion, our results highlight the regulatory role of SST in intracellular Ca2+ homeostasis. The neuroprotective role of SST via axonal regeneration and synaptic integrity is corroborated by regulating changes in CRMP2; however, SST-mediated changes in the blockade of Ca2+ influx, calpain expression, and toxicity did not correlate with CDK5 expression and p35/25 accumulation. To summarize, our findings suggest two independent mechanisms by which SST mediates neuroprotection and confirms the therapeutic implications of SST in AD as well as in other neurodegenerative diseases where the effective regulation of calcium homeostasis is required for a better prognosis.
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Affiliation(s)
| | | | | | | | - Ujendra Kumar
- Correspondence: ; Tel.: +1-604-827-3660; Fax: +1-604-822-3035
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9
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Costanzi E, Simioni C, Conti I, Laface I, Varano G, Brenna C, Neri LM. Two neuroendocrine G protein-coupled receptor molecules, somatostatin and melatonin: Physiology of signal transduction and therapeutic perspectives. J Cell Physiol 2020; 236:2505-2518. [PMID: 32989768 DOI: 10.1002/jcp.30062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/04/2020] [Accepted: 09/10/2020] [Indexed: 12/15/2022]
Abstract
Recent studies have shown that G protein-coupled receptors (GPCRs), the largest signal-conveying receptor family, are targets for mutations occurring frequently in different cancer types. GPCR alterations associated with cancer development represent significant challenges for the discovery and the advancement of targeted therapeutics. Among the different molecules that can activate GPCRs, we focused on two molecules that exert their biological actions regulating many typical features of tumorigenesis such as cellular proliferation, survival, and invasion: somatostatin and melatonin. The modulation of signaling pathways, that involves these two molecules, opens an interesting scenario for cancer therapy, with the opportunity to act at different molecular levels. Therefore, the aim of this review is the analysis of the biological activity and the therapeutic potential of somatostatin and melatonin, displaying a high affinity for GPCRs, that interfere with cancer development and maintenance.
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Affiliation(s)
- Eva Costanzi
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Carolina Simioni
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy.,Laboratory for Technologies of Advanced Therapies (LTTA)-Electron Microscopy Center, University of Ferrara, Ferrara, Italy
| | - Ilaria Conti
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Ilaria Laface
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Gabriele Varano
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Cinzia Brenna
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Luca M Neri
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy.,Laboratory for Technologies of Advanced Therapies (LTTA)-Electron Microscopy Center, University of Ferrara, Ferrara, Italy
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10
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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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11
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Vázquez-Borrego MC, Gupta V, Ibáñez-Costa A, Gahete MD, Venegas-Moreno E, Toledano-Delgado Á, Cano DA, Blanco-Acevedo C, Ortega-Salas R, Japón MA, Barrera-Martín A, Vasiljevic A, Hill J, Zhang S, Halem H, Solivera J, Raverot G, Gálvez MA, Soto-Moreno A, Paez-Pereda M, Culler MD, Castaño JP, Luque RM. A Somatostatin Receptor Subtype-3 (SST 3) Peptide Agonist Shows Antitumor Effects in Experimental Models of Nonfunctioning Pituitary Tumors. Clin Cancer Res 2020; 26:957-969. [PMID: 31624102 DOI: 10.1158/1078-0432.ccr-19-2154] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/08/2019] [Accepted: 10/14/2019] [Indexed: 11/16/2022]
Abstract
PURPOSE Somatostatin analogues (SSA) are efficacious and safe treatments for a variety of neuroendocrine tumors, especially pituitary neuroendocrine tumors (PitNET). Their therapeutic effects are mainly mediated by somatostatin receptors SST2 and SST5. Most SSAs, such as octreotide/lanreotide/pasireotide, are either nonselective or activate mainly SST2. However, nonfunctioning pituitary tumors (NFPTs), the most common PitNET type, mainly express SST3 and finding peptides that activate this particular somatostatin receptor has been very challenging. Therefore, the main objective of this study was to identify SST3-agonists and characterize their effects on experimental NFPT models. EXPERIMENTAL DESIGN Binding to SSTs and cAMP level determinations were used to screen a peptide library and identify SST3-agonists. Key functional parameters (cell viability/caspase activity/chromogranin-A secretion/mRNA expression/intracellular signaling pathways) were assessed on NFPT primary cell cultures in response to SST3-agonists. Tumor growth was assessed in a preclinical PitNET mouse model treated with a SST3-agonist. RESULTS We successfully identified the first SST3-agonist peptides. SST3-agonists lowered cell viability and chromogranin-A secretion, increased apoptosis in vitro, and reduced tumor growth in a preclinical PitNET model. As expected, inhibition of cell viability in response to SST3-agonists defined two NFPT populations: responsive and unresponsive, wherein responsive NFPTs expressed more SST3 than unresponsive NFPTs and exhibited a profound reduction of MAPK, PI3K-AKT/mTOR, and JAK/STAT signaling pathways upon SST3-agonist treatments. Concurrently, SSTR3 silencing increased cell viability in a subset of NFPTs. CONCLUSIONS This study demonstrates that SST3-agonists activate signaling mechanisms that reduce NFPT cell viability and inhibit pituitary tumor growth in experimental models that expresses SST3, suggesting that targeting this receptor could be an efficacious treatment for NFPTs.
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Affiliation(s)
- Mari C Vázquez-Borrego
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | | | - Alejandro Ibáñez-Costa
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | - Manuel D Gahete
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | - Eva Venegas-Moreno
- Metabolism and Nutrition Unit, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla (IBIS), Sevilla, Spain
| | - Álvaro Toledano-Delgado
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,Service of Neurosurgery, HURS, Cordoba, Spain
| | - David A Cano
- Metabolism and Nutrition Unit, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla (IBIS), Sevilla, Spain
| | - Cristóbal Blanco-Acevedo
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,Service of Neurosurgery, HURS, Cordoba, Spain
| | - Rosa Ortega-Salas
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,Anatomical Pathology Service, HURS, Cordoba, Spain
| | - Miguel A Japón
- Department of Pathology, Hospital Universitario Virgen del Rocío, Sevilla, Spain
| | - Ana Barrera-Martín
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,Service of Endocrinology and Nutrition, IMIBIC, HURS, Cordoba, Spain
| | - Alexandre Vasiljevic
- Faculté de Médecine Lyon Est, Université Lyon 1, Lyon, France.,INSERM U1052, CNRS UMR5286, Cancer Research Centre of Lyon, Lyon, France.,Centre de Pathologie et de Biologie, Groupement Hospitalier Est, Hospices Civils de Lyon, Lyon, France
| | - Jason Hill
- IPSEN Bioscience, Cambridge, Massachusetts
| | | | | | - Juan Solivera
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,Service of Neurosurgery, HURS, Cordoba, Spain
| | - Gérald Raverot
- Faculté de Médecine Lyon Est, Université Lyon 1, Lyon, France.,INSERM U1052, CNRS UMR5286, Cancer Research Centre of Lyon, Lyon, France.,Fédération d'endocrinologie, Groupement Hospitalier Est, Hospices Civils de Lyon, Bron, France
| | - María A Gálvez
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,Service of Endocrinology and Nutrition, IMIBIC, HURS, Cordoba, Spain
| | - Alfonso Soto-Moreno
- Metabolism and Nutrition Unit, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla (IBIS), Sevilla, Spain
| | | | | | - Justo P Castaño
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain. .,Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | - Raúl M Luque
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain. .,Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain.,Reina Sofia University Hospital (HURS), Cordoba, Spain.,CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
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12
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Treppiedi D, Giardino E, Catalano R, Mangili F, Vercesi P, Sala E, Locatelli M, Arosio M, Spada A, Mantovani G, Peverelli E. Somatostatin analogs regulate tumor corticotrophs growth by reducing ERK1/2 activity. Mol Cell Endocrinol 2019; 483:31-38. [PMID: 30611770 DOI: 10.1016/j.mce.2018.12.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 12/11/2018] [Accepted: 12/31/2018] [Indexed: 12/31/2022]
Abstract
Pasireotide has been associated with tumor shrinkage in patients with Cushing's disease subjected to long term treatment. However, to date the implicated molecular mechanisms are poorly elucidated. Here, we tested pasireotide-mediated cytostatic and cytotoxic effects in ACTH-secreting primary tumor cultures and murine corticotroph tumor cell line, AtT-20 cells. We found somatostatin receptor type 5 (SST5) expressed in 17 different ACTH-secreting tumors and SST2 detectable in 15 out of the 17 tissues. Pasireotide caused a slight but significant in vitro inhibition of cell growth in 3 out of 6 ACTH-secreting primary cultures (-12.1 ± 4.3%, P < 0.01 at 10 nM), remarkably reduced phospho-ERK1/2 levels in 5 out of 8 samples (-36.4 ± 20.5%, P < 0.01 at 1 μM) and triggered an increase of caspase 3/7 activity in 2 of 4 tumors (17 ± 3.6%, P < 0.05 at 1 μM). Accordingly, in AtT-20 cells, pasireotide significantly inhibited cell proliferation (-10.5 ± 7.7% at 10 nM, P < 0.05; -13.9 ± 10.9% at 100 nM, P < 0.05; -26.8 ± 8.9% at 1 μM, P < 0.01). Similar antiproliferative actions were exerted by BIM23206 and BIM23120 (SST5&2 selective ligands, respectively), whereas octreotide was effective when used at 1 μM (-13.3 ± 9.1%, P < 0.05). Moreover, a reduction of phospho-ERK1/2 was observed upon pasireotide and BIM23206 treatment (-8.4 ± 28.6%, P < 0.01 and -51.4 ± 15.9%, P < 0.001 at 10 nM, respectively) but not after octreotide and BIM23120 incubation. Finally, pasireotide was able to induce cell apoptosis in AtT-20 cells at lower concentration than octreotide. Altogether these data indicate a downstream implication of SST5-mediated phospho-ERK1/2 inhibition by pasireotide resulting in ACTH-secreting tumor cells proliferation reduction. Moreover, we describe for the first time a pro-apoptotic effect of pasireotide in corticotrophs.
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Affiliation(s)
- Donatella Treppiedi
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Elena Giardino
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Rosa Catalano
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy; PhD Program in Endocrinological Sciences, Sapienza University of Rome, Rome, Italy
| | - Federica Mangili
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Pietro Vercesi
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Elisa Sala
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Marco Locatelli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurosurgery Unit, Milan, Italy
| | - Maura Arosio
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Anna Spada
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Giovanna Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.
| | - Erika Peverelli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrine Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
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13
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Rossi V, Di Zazzo E, Galasso G, De Rosa C, Abbondanza C, Sinisi AA, Altucci L, Migliaccio A, Castoria G. Estrogens Modulate Somatostatin Receptors Expression and Synergize With the Somatostatin Analog Pasireotide in Prostate Cells. Front Pharmacol 2019; 10:28. [PMID: 30828298 PMCID: PMC6384260 DOI: 10.3389/fphar.2019.00028] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/11/2019] [Indexed: 12/15/2022] Open
Abstract
Prostate cancer (PC) is one of the most frequently diagnosed cancers and a leading cause of cancer-related deaths in Western society. Current PC therapies prevalently target the functions of androgen receptor (AR) and may only be effective within short time periods, beyond which the majority of PC patients progress to castration-resistant PC (CRPC) and metastatic disease. The role of estradiol/estradiol receptor (ER) axis in prostate transformation and PC progression is well established. Further, considerable efforts have been made to investigate the mechanism by which somatostatin (SST) and somatostatin receptors (SSTRs) influence PC growth and progression. A number of therapeutic strategies, such as the combination of SST analogs with other drugs, show, indeed, strong promise. However, the effect of the combined treatment of SST analogs and estradiol on proliferation, epithelial mesenchyme transition (EMT) and migration of normal- and cancer-derived prostate cells has not been investigated so far. We now report that estradiol plays anti-proliferative and pro-apoptotic effect in non-transformed EPN prostate cells, which express both ERα and ERβ. A weak apoptotic effect is observed in transformed CPEC cells that only express low levels of ERβ. Estradiol increases, mainly through ERα activation, the expression of SSTRs in EPN, but not CPEC cells. As such, the hormone enhances the anti-proliferative effect of the SST analog, pasireotide in EPN, but not CPEC cells. Estradiol does not induce EMT and the motility of EPN cells, while it promotes EMT and migration of CPEC cells. Addition of pasireotide does not significantly modify these responses. Altogether, our results suggest that pasireotide may be used, alone or in combination with other drugs, to limit the growth of prostate proliferative diseases, provided that both ER isoforms (α and β) are present. Further investigations are needed to better define the cross talk between estrogens and SSTRs as well as its role in PC.
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Affiliation(s)
- Valentina Rossi
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
| | - Erika Di Zazzo
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
| | - Giovanni Galasso
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
| | - Caterina De Rosa
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
| | - Ciro Abbondanza
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
| | - Antonio A Sinisi
- Dipartimento di Scienze Mediche, Chirurgiche, Neurologiche, Metaboliche e dell'Invecchiamento, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
| | - Lucia Altucci
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
| | - Antimo Migliaccio
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
| | - Gabriella Castoria
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania "Luigi Vanvitelli", Naples, Italy
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14
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Somvanshi RK, Jhajj A, Heer M, Kumar U. Characterization of somatostatin receptors and associated signaling pathways in pancreas of R6/2 transgenic mice. Biochim Biophys Acta Mol Basis Dis 2018; 1864:359-373. [DOI: 10.1016/j.bbadis.2017.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/22/2017] [Accepted: 11/01/2017] [Indexed: 01/12/2023]
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15
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Orciani M, Caffarini M, Sorgentoni G, Ricciuti RA, Arnaldi G, Di Primio R. Effects of somatostatin and its analogues on progenitor mesenchymal cells isolated from human pituitary adenomas. Pituitary 2017; 20:251-260. [PMID: 27796709 DOI: 10.1007/s11102-016-0770-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE Progenitor mesenchymal cells (PMCs) have been found also in epithelial tumors and may derive from cancer stem cells (CSCs) by EMT mechanism. In this scenario, the effects of traditionally drugs on PMCs become of primary concern for therapeutic approaches. Previously, we isolated PMCs from acromegalic (GHomas) and not-functioning pituitary adenomas (NFPAs). Here we evaluate: (1) the role of EMT on their origin; (2) the presence of the somatostatin receptors (SSTR1-5); (3) the effects of somatostatin (SST) and its analogues (SSAs) on PMCs proliferation, apoptosis and SSTR1-5 expression. METHODS PMCs were isolated from GHomas and NFPAs; the expression of E-CADHERIN and TGFβRII (referred to EMT), the expression of the SSTR1-5 as well as the proliferation and apoptosis were tested before and after drugs administration. RESULTS Results show a decrease of E-CADHERIN and an increase of TGFβRII, confirming an EMT involvement; SSTR1-5 are more expressed by PMCs from GHomas than from NFPAs. SST and SSAs administration does not affect cell proliferation and SSTR1-5 expression on PMCs from NFPAs while in PMCs from GHomas, cell proliferation showed a marked decrease and a corresponding increase in the expression of SSTR1-2. Apoptosis rate and EMT were not affected by drugs administration. CONCLUSIONS Results indicate as EMT may be related to the presence of PMCs on pituitary tumors; SSAs, currently used in the management of human GHomas, exert anti-proliferative effect also in PMCs that, because of their derivation from CSCs, may be a new meaningful target for drugs treatment.
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Affiliation(s)
- Monia Orciani
- Department of Clinical and Molecular Sciences - Histology, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy.
| | - Miriam Caffarini
- Department of Clinical and Molecular Sciences - Histology, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy
| | - Giulia Sorgentoni
- Department of Clinical and Molecular Sciences - Histology, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy
| | - Riccardo Antonio Ricciuti
- Department of Neurological, Medical and Surgery Sciences, Azienda Ospedali Riuniti di Ancona, Via Conca, 60126, Ancona, Italy
| | - Giorgio Arnaldi
- Department of Clinical and Molecular Sciences - Endocrinology, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy
| | - Roberto Di Primio
- Department of Clinical and Molecular Sciences - Histology, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy
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16
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Lehmann A, Kliewer A, Günther T, Nagel F, Schulz S. Identification of Phosphorylation Sites Regulating sst3 Somatostatin Receptor Trafficking. Mol Endocrinol 2016; 30:645-59. [PMID: 27101376 DOI: 10.1210/me.2015-1244] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The human somatostatin receptor 3 (sst3) is expressed in about 50% of all neuroendocrine tumors and hence a promising target for multireceptor somatostatin analogs. The sst3 receptor is unique among ssts in that it exhibits a very long intracellular C-terminal tail containing a huge number of potential phosphate acceptor sites. Consequently, our knowledge about the functional role of the C-terminal tail in sst3 receptor regulation is very limited. Here, we have generated a series of phosphorylation-deficient mutants that enabled us to determine crucial sites for its agonist-induced β-arrestin mobilization, internalization, and down-regulation. Based on this information, we generated phosphosite-specific antibodies for C-terminal Ser(337)/Thr(341), Thr(348), and Ser(361) that enabled us to investigate the temporal patterns of sst3 phosphorylation and dephosphorylation. We found that the endogenous ligand somatostatin induced a rapid and robust phosphorylation that was completely blocked by the sst3 antagonist NVP-ACQ090. The stable somatostatin analogs pasireotide and octreotide promoted clearly less phosphorylation compared with somatostatin. We also show that sst3 phosphorylation occurred within seconds to minutes, whereas dephosphorylation of the sst3 receptor occurred at a considerable slower rate. In addition, we also identified G protein-coupled receptor kinases 2 and 3 and protein phosphatase 1α and 1β as key regulators of sst3 phosphorylation and dephosphorylation, respectively. Thus, we here define the C-terminal phosphorylation motif of the human sst3 receptor that regulates its agonist-promoted phosphorylation, β-arrestin recruitment, and internalization of this clinically relevant receptor.
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Affiliation(s)
- Andreas Lehmann
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, D-07747 Jena, Germany
| | - Andrea Kliewer
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, D-07747 Jena, Germany
| | - Thomas Günther
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, D-07747 Jena, Germany
| | - Falko Nagel
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, D-07747 Jena, Germany
| | - Stefan Schulz
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, D-07747 Jena, Germany
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17
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War SA, Kim B, Kumar U. Human somatostatin receptor-3 distinctively induces apoptosis in MCF-7 and cell cycle arrest in MDA-MB-231 breast cancer cells. Mol Cell Endocrinol 2015; 413:129-44. [PMID: 26112183 DOI: 10.1016/j.mce.2015.06.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/12/2015] [Accepted: 06/17/2015] [Indexed: 12/29/2022]
Abstract
Somatostatin (SST) mediates cytostatic and pro-apoptotic effects through five somatostatin receptors (SSTR1-5). The modest clinical benefits of SST analogs in cancers of different origin such as breast cancer are attributed to diminished SSTRs expression at tumor sites. In the present study, SSTR3 was overexpressed in MCF-7 and MDA-MB-231, and analyzed for downstream signaling molecules associated with cytostatic and cytotoxic effect. Cells overexpressing SSTR3 displayed inhibition of EGF induced proliferation and enhanced antiproliferative effect of SSTR3-specific agonist in comparison to non-transfected cells. SSTR3 overexpression in MCF-7 cells (R3-MCF-7) constitutively enhanced TUNEL staining, PARP-1 and p27(Kip1) expression suggesting apoptosis and cell-cycle arrest. Conversely, R3-MB-231 cells with SSTR3 overexpression exerted cytostatic and were devoid of any cytotoxic effects. The expression of PTP-1C and the status of ERK1/2, p38 and PI3K phosphorylation was modulated in a cell-specific manner. These findings provide new insights in understanding the antiproliferative role of SSTR3 in breast tumor biology.
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Affiliation(s)
- Sajad A War
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Brian Kim
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ujendra Kumar
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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Yuan D, Shen J, Yan Y, Wu X, Li A, Guo A, Wu Y, Duan C, Shen J, Tang C, Zhang D, Ji Y. Upregulated expression of SSTR1 is involved in neuronal apoptosis and is coupled to the reduction of bcl-2 following intracerebral hemorrhage in adult rats. Cell Mol Neurobiol 2014; 34:951-61. [PMID: 25035058 DOI: 10.1007/s10571-014-0081-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/29/2014] [Indexed: 10/25/2022]
Abstract
Somatostatins are peptide hormones that regulate diverse cellular processes, such as neurotransmission, cell proliferation, apoptosis, and endocrine signaling as well as inhibiting the release of many hormones and other secretory proteins. SSTR1 is a member of the superfamily of somatostatin receptors possessing seven-transmembrane segments. Aberrant expression of SSTR1 has been implicated in several human diseases, including pseudotumor cerebri, and oncogenic osteomalacia. In this study, we investigated a potential role of SSTR1 in the regulation of neuronal apoptosis in the course of intracerebral hemorrhage (ICH). A rat ICH model in the caudate putamen was established and subjected to behavioral tests. Western blot and immunohistochemistry indicated a remarkable up-regulation of SSTR1 expression surrounding the hematoma after ICH. Double-labeled immunofluorescence showed that SSTR1 was mostly co-localized with neurons, and was rarely distributed in activated astrocytes and microglia. Additionally, SSTR1 co-localized with active-caspase-3 and bcl-2 around the hematoma. The expression of active-caspase-3 was parallel with that of SSTR1 in a time-dependent manner. In addition, SSTR1 knockdown specifically resulted in reduced neuronal apoptosis in PC12 cells. All our findings suggested that up-regulated SSTR1 contributed to neuronal apoptosis after ICH, which was accompanied with reduced expression of bcl-2.
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Affiliation(s)
- Damin Yuan
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Department of Immunology, Medical College, Nantong University, Nantong, 226001, People's Republic of China
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Chalabi M, Duluc C, Caron P, Vezzosi D, Guillermet-Guibert J, Pyronnet S, Bousquet C. Somatostatin analogs: does pharmacology impact antitumor efficacy? Trends Endocrinol Metab 2014; 25:115-27. [PMID: 24405892 DOI: 10.1016/j.tem.2013.11.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 11/05/2013] [Accepted: 11/15/2013] [Indexed: 01/17/2023]
Abstract
Somatostatin is an endogenous inhibitor of secretion and cell proliferation. These features render somatostatin a logical candidate for the management of neuroendocrine tumors that express somatostatin receptors. Synthetic somatostatin analogs (SSAs) have longer half-lives than somatostatin, but have similar activities, and are used for the treatment of these types of disorders. Interest has focused on novel multireceptor analogs with broader affinity to several of the five somatostatin receptors, thereby presenting putatively higher antitumor activities. Recent evidence indicates that SSAs cannot be considered mimics of native somatostatin in regulating signaling pathways downstream of receptors. Here we review this knowledge, discuss the concept of biased agonism, and highlight what considerations need to be taken into account for the optimal clinical use of SSAs.
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Affiliation(s)
- Mounira Chalabi
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1037, Centre de Recherche en Cancérologie de Toulouse (CRCT), Equipe labellisée Ligue Contre le Cancer and Laboratoire d'Excellence Toulouse Cancer (TOUCAN), 31432 Toulouse, France; Université Toulouse III Paul Sabatier, 31062 Toulouse, France
| | - Camille Duluc
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1037, Centre de Recherche en Cancérologie de Toulouse (CRCT), Equipe labellisée Ligue Contre le Cancer and Laboratoire d'Excellence Toulouse Cancer (TOUCAN), 31432 Toulouse, France; Université Toulouse III Paul Sabatier, 31062 Toulouse, France
| | - Philippe Caron
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1037, Centre de Recherche en Cancérologie de Toulouse (CRCT), Equipe labellisée Ligue Contre le Cancer and Laboratoire d'Excellence Toulouse Cancer (TOUCAN), 31432 Toulouse, France; Université Toulouse III Paul Sabatier, 31062 Toulouse, France; Service d'Endocrinologie et Maladies Métaboliques, Pôle Cardio-Vasculaire et Métabolique, Centre Hospitalier Universitaire (CHU) Larrey, 31059 Toulouse, France
| | - Delphine Vezzosi
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1037, Centre de Recherche en Cancérologie de Toulouse (CRCT), Equipe labellisée Ligue Contre le Cancer and Laboratoire d'Excellence Toulouse Cancer (TOUCAN), 31432 Toulouse, France; Université Toulouse III Paul Sabatier, 31062 Toulouse, France; Service d'Endocrinologie et Maladies Métaboliques, Pôle Cardio-Vasculaire et Métabolique, Centre Hospitalier Universitaire (CHU) Larrey, 31059 Toulouse, France
| | - Julie Guillermet-Guibert
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1037, Centre de Recherche en Cancérologie de Toulouse (CRCT), Equipe labellisée Ligue Contre le Cancer and Laboratoire d'Excellence Toulouse Cancer (TOUCAN), 31432 Toulouse, France; Université Toulouse III Paul Sabatier, 31062 Toulouse, France
| | - Stéphane Pyronnet
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1037, Centre de Recherche en Cancérologie de Toulouse (CRCT), Equipe labellisée Ligue Contre le Cancer and Laboratoire d'Excellence Toulouse Cancer (TOUCAN), 31432 Toulouse, France; Université Toulouse III Paul Sabatier, 31062 Toulouse, France
| | - Corinne Bousquet
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1037, Centre de Recherche en Cancérologie de Toulouse (CRCT), Equipe labellisée Ligue Contre le Cancer and Laboratoire d'Excellence Toulouse Cancer (TOUCAN), 31432 Toulouse, France; Université Toulouse III Paul Sabatier, 31062 Toulouse, France.
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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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War SA, Kumar U. Coexpression of human somatostatin receptor-2 (SSTR2) and SSTR3 modulates antiproliferative signaling and apoptosis. J Mol Signal 2012; 7:5. [PMID: 22651821 PMCID: PMC3403965 DOI: 10.1186/1750-2187-7-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 05/31/2012] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Somatostatin (SST) via five Gi coupled receptors namely SSTR1-5 is known to inhibit cell proliferation by cytostatic and cytotoxic mechanisms. Heterodimerization plays a crucial role in modulating the signal transduction pathways of SSTR subtypes. In the present study, we investigated human SSTR2/SSTR3 heterodimerization, internalization, MAPK signaling, cell proliferation and apoptosis in HEK-293 cells in response to SST and specific agonists for SSTR2 and SSTR3. RESULTS Although in basal conditions, SSTR2 and SSTR3 colocalize at the plasma membrane and exhibit heterodimerization, the cell surface distribution of both receptors decreased upon agonist activation and was accompanied by a parallel increase in intracellular colocalization. Receptors activation by SST and specific agonists significantly decreased cAMP levels in cotransfected cells in comparison to control. Agonist-mediated modulation of pERK1/2 was time and concentration-dependent, and pronounced in serum-deprived conditions. pERK1/2 was inhibited in response to SST; conversely receptor-specific agonist treatment caused inhibition at lower concentration and activation at higher concentration. Strikingly, ERK1/2 phosphorylation was sustained upon prolonged treatment with SST but not with receptor-specific agonists. On the other hand, SST and receptor-specific agonists modulated p38 phosphorylation time-dependently. The receptor activation in cotransfected cells exhibits Gi-dependent inhibition of cell proliferation attributed to increased PARP-1 expression and TUNEL staining, whereas induction of p21 and p27Kip1 suggests a cytostatic effect. CONCLUSION Our study provides new insights in SSTR2/SSTR3 mediated signaling which might help in better understanding of the molecular interactions involving SSTRs in tumor biology.
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Affiliation(s)
- Sajad A War
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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Somvanshi RK, Kumar U. Pathophysiology of GPCR Homo- and Heterodimerization: Special Emphasis on Somatostatin Receptors. Pharmaceuticals (Basel) 2012; 5:417-46. [PMID: 24281555 PMCID: PMC3763651 DOI: 10.3390/ph5050417] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/18/2012] [Accepted: 04/19/2012] [Indexed: 12/19/2022] Open
Abstract
G-protein coupled receptors (GPCRs) are cell surface proteins responsible for translating >80% of extracellular reception to intracellular signals. The extracellular information in the form of neurotransmitters, peptides, ions, odorants etc is converted to intracellular signals via a wide variety of effector molecules activating distinct downstream signaling pathways. All GPCRs share common structural features including an extracellular N-terminal, seven-transmembrane domains (TMs) linked by extracellular/intracellular loops and the C-terminal tail. Recent studies have shown that most GPCRs function as dimers (homo- and/or heterodimers) or even higher order of oligomers. Protein-protein interaction among GPCRs and other receptor proteins play a critical role in the modulation of receptor pharmacology and functions. Although ~50% of the current drugs available in the market target GPCRs, still many GPCRs remain unexplored as potential therapeutic targets, opening immense possibility to discover the role of GPCRs in pathophysiological conditions. This review explores the existing information and future possibilities of GPCRs as tools in clinical pharmacology and is specifically focused for the role of somatostatin receptors (SSTRs) in pathophysiology of diseases and as the potential candidate for drug discovery.
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Affiliation(s)
- Rishi K Somvanshi
- Faculty of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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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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Kumar U. Cross-talk and modulation of signaling between somatostatin and growth factor receptors. Endocrine 2011; 40:168-80. [PMID: 21870170 DOI: 10.1007/s12020-011-9524-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 08/11/2011] [Indexed: 12/19/2022]
Abstract
The process of homo- and/or heterodimerization of G-protein coupled receptors (GPCRs) and receptor tyrosine kinase (RTK) families are crucial for implicating the fundamental properties of receptor proteins including receptor expression, trafficking, and desensitization as well as signal transduction. The members of GPCR and RTK family constitute largest cell surface receptor proteins and regulate physiological functions of cells in response to external and internal stimuli. Notably, GPCRs and RTKs play major role in regulation of several key cellular functions which are associated with several pathological conditions including cancer biology, neurodegenerative and cardiovascular diseases. The focus of this review is to highlight the recent findings on the possible cross-talk between somatostatin receptors (members of GPCR family) and growth factor receptors like epidermal growth factor receptors (members of RTK family). Furthermore, functional consequences of such an interaction in modulation of signaling pathways linked to pathological conditions specifically in cancer are discussed.
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Affiliation(s)
- Ujendra Kumar
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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