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Ma Y, Gao F. Advances of radiolabeled GRPR ligands for PET/CT imaging of cancers. Cancer Imaging 2024; 24:19. [PMID: 38279185 PMCID: PMC10811881 DOI: 10.1186/s40644-024-00658-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 01/09/2024] [Indexed: 01/28/2024] Open
Abstract
GRPR is a type of seven-transmembrane G-protein coupled receptor that belongs to the bombesin protein receptor family. It is highly expressed in various cancers, including prostate cancer, breast cancer, lung cancer, gastrointestinal cancer, and so on. As a result, molecular imaging studies have been conducted using radiolabeled GRPR ligands for tumor diagnosis, as well as monitoring of recurrence and metastasis. In this paper, we provided a comprehensive overview of relevant literature from the past two decades, with a specific focus on the advancements made in radiolabeled GRPR ligands for imaging prostate cancer and breast cancer.
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Affiliation(s)
- Yuze Ma
- Research Center for Experimental Nuclear Medicine, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Feng Gao
- Research Center for Experimental Nuclear Medicine, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China.
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Liolios C, Patsis C, Lambrinidis G, Tzortzini E, Roscher M, Bauder-Wüst U, Kolocouris A, Kopka K. Investigation of Tumor Cells and Receptor-Ligand Simulation Models for the Development of PET Imaging Probes Targeting PSMA and GRPR and a Possible Crosstalk between the Two Receptors. Mol Pharm 2022; 19:2231-2247. [PMID: 35467350 DOI: 10.1021/acs.molpharmaceut.2c00070] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Prostate-specific membrane antigen (PSMA) and gastrin-releasing peptide receptor (GRPR) have both been used in nuclear medicine as targets for molecular imaging and therapy of prostate (PCa) and breast cancer (BCa). Three bioconjugate probes, the PSMA specific: [68Ga]Ga-1, ((HBED-CC)-Ahx-Lys-NH-CO-NH Glu or PSMA-11), the GRPR specific: [68Ga]Ga-2, ((HBED-CC)-4-amino-1-carboxymethyl piperidine-[D-Phe6, Sta13]BN(6-14), a bombesin (BN) analogue), and 3 (the BN analogue: 4-amino-1-carboxymethyl piperidine-[(R)-Phe6, Sta13]BN(6-14) connected with the fluorescent dye, BDP-FL), were synthesized and tested in vitro with PCa and BCa cell lines, more specifically, with PCa cells, PC-3 and LNCaP, with BCa cells, T47D, MDA-MB-231, and with the in-house created PSMA-overexpressing PC-3(PSMA), T47D(PSMA), and MDA-MB-231(PSMA). In addition, biomolecular simulations were conducted on the association of 1 and 2 with PSMA and GRPR. The PSMA overexpression resulted in an increase of cell-bound radioligand [68Ga]Ga-1 (PSMA) for PCa and BCa cells and also of [68Ga]Ga-2 (GRPR), especially in those cell lines already expressing GRPR. The results were confirmed by fluorescence-activated cell sorting with a PE-labeled PSMA-specific antibody and the fluorescence tracer 3. The docking calculations and molecular dynamics simulations showed how 1 enters the PSMA funnel region and how pharmacophore Glu-urea-Lys interacts with the arginine patch, the S1', and S1 subpockets by forming hydrogen and van der Waals bonds. The chelating moiety of 1, that is, HBED-CC, forms additional stabilizing hydrogen bonding and van der Waals interactions in the arene-binding site. Ligand 2 is diving into the GRPR transmembrane (TM) helical cavity, thereby forming hydrogen bonds through its amidated end, water-mediated hydrogen bonds, and π-π interactions. Our results provide valuable information regarding the molecular mechanisms involved in the interactions of 1 and 2 with PSMA and GRPR, which might be useful for the diagnostic imaging and therapy of PCa and BCa.
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Affiliation(s)
- Christos Liolios
- Division of Radiopharmaceutical Chemistry, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Radiochemical Studies Laboratory, INRASTES, N.C.S.R. "Demokritos", Agia Paraskevi Attikis, 15310 Athens, Greece.,Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimioupolis-Zografou, 15771 Athens, Greece
| | - Christos Patsis
- Division of Cell Plasticity and Epigenetic Remodelling, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Department of Translational Oncology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - George Lambrinidis
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimioupolis-Zografou, 15771 Athens, Greece
| | - Efpraxia Tzortzini
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimioupolis-Zografou, 15771 Athens, Greece
| | - Mareike Roscher
- Division of Radiopharmaceutical Chemistry, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Ulrike Bauder-Wüst
- Division of Radiopharmaceutical Chemistry, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Antonios Kolocouris
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimioupolis-Zografou, 15771 Athens, Greece
| | - Klaus Kopka
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany.,Faculty of Chemistry and Food Chemistry, School of Science, Technical University Dresden, Lebensmittelchemie Chemiegebäude, Raum 413 Bergstr. 66, 01069 Dresden, Germany
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Nock BA, Kaloudi A, Kanellopoulos P, Janota B, Bromińska B, Iżycki D, Mikołajczak R, Czepczynski R, Maina T. [ 99mTc]Tc-DB15 in GRPR-Targeted Tumor Imaging with SPECT: From Preclinical Evaluation to the First Clinical Outcomes. Cancers (Basel) 2021; 13:5093. [PMID: 34680243 DOI: 10.3390/cancers13205093] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 12/15/2022] Open
Abstract
Diagnostic imaging and radionuclide therapy of prostate (PC) and breast cancer (BC) using radiolabeled gastrin-releasing peptide receptor (GRPR)-antagonists represents a promising approach. We herein propose the GRPR-antagonist based radiotracer [99mTc]Tc-DB15 ([99mTc]Tc-N4-AMA-DGA-DPhe6,Sar11,LeuNHEt13]BBN(6-13); N4: 6-carboxy-1,4,8,11-tetraazaundecane, AMA: aminomethyl-aniline, DGA: diglycolic acid) as a new diagnostic tool for GRPR-positive tumors applying SPECT/CT. The uptake of [99mTc]Tc-DB15 was tested in vitro in mammary (T-47D) and prostate cancer (PC-3) cells and in vivo in T-47D or PC-3 xenograft-bearing mice as well as in BC patients. DB15 showed high GRPR-affinity (IC50 = 0.37 ± 0.03 nM) and [99mTc]Tc-DB15 strongly bound to the cell-membrane of T-47D and PC-3 cells, according to a radiolabeled antagonist profile. In mice, the radiotracer showed high and prolonged GRPR-specific uptake in PC-3 (e.g., 25.56 ± 2.78 %IA/g vs. 0.72 ± 0.12 %IA/g in block; 4 h pi) and T-47D (e.g., 15.82 ± 3.20 %IA/g vs. 3.82 ± 0.30 %IA/g in block; 4 h pi) tumors, while rapidly clearing from background. In patients with advanced BC, the tracer could reveal several bone and soft tissue metastases on SPECT/CT. The attractive pharmacokinetic profile of [99mTc]DB15 in mice and its capability to target GRPR-positive BC lesions in patients highlight its prospects for a broader clinical use, an option currently being explored by ongoing clinical studies.
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Hoppenz P, Els-Heindl S, Kellert M, Kuhnert R, Saretz S, Lerchen HG, Köbberling J, Riedl B, Hey-Hawkins E, Beck-Sickinger AG. A Selective Carborane-Functionalized Gastrin-Releasing Peptide Receptor Agonist as Boron Delivery Agent for Boron Neutron Capture Therapy. J Org Chem 2019; 85:1446-1457. [PMID: 31813224 DOI: 10.1021/acs.joc.9b02406] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Boron neutron capture therapy (BNCT) allows the selective elimination of malignant tumor cells without affecting healthy tissue. Although this binary radiotherapy approach has been known for decades, BNCT failed to reach the daily clinics to date. One of the reasons is the lack of selective boron delivery agents. Using boron loaded peptide conjugates, which address G protein-coupled receptors overexpressed on tumor cells allow the intracellular accumulation of boron. The gastrin-releasing peptide receptor (GRPR) is a well-known target in cancer diagnosis and can potentially be used for BNCT. Here, we present the successful introduction of multiple bis-deoxygalactosyl-carborane building blocks to the GRPR-selective ligand [d-Phe6, β-Ala11, Ala13, Nle14]Bn(6-14) (sBB2L) generating peptide conjugates with up to 80 boron atoms per molecule. Receptor activation was retained, metabolic stability was increased, and uptake into PC3 cells was proven without showing any intrinsic cytotoxicity. Furthermore, undesired uptake into liver cells was suppressed by using l-deoxygalactosyl modified carborane building blocks. Due to its high boron loading and excellent GRPR selectivity, this conjugate can be considered as a promising boron delivery agent for BNCT.
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Affiliation(s)
- Paul Hoppenz
- Institute of Biochemistry, Faculty of Life Sciences , Leipzig University , Brüderstrasse 34 , 04103 Leipzig , Germany
| | - Sylvia Els-Heindl
- Institute of Biochemistry, Faculty of Life Sciences , Leipzig University , Brüderstrasse 34 , 04103 Leipzig , Germany
| | - Martin Kellert
- Institute of Inorganic Chemistry , Leipzig University , Johannisallee 29 , 04103 Leipzig , Germany
| | - Robert Kuhnert
- Institute of Inorganic Chemistry , Leipzig University , Johannisallee 29 , 04103 Leipzig , Germany
| | - Stefan Saretz
- Institute of Inorganic Chemistry , Leipzig University , Johannisallee 29 , 04103 Leipzig , Germany
| | | | | | - Bernd Riedl
- Bayer AG , Aprather Weg 18A , Wuppertal , Germany
| | - Evamarie Hey-Hawkins
- Institute of Inorganic Chemistry , Leipzig University , Johannisallee 29 , 04103 Leipzig , Germany
| | - Annette G Beck-Sickinger
- Institute of Biochemistry, Faculty of Life Sciences , Leipzig University , Brüderstrasse 34 , 04103 Leipzig , Germany
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Hoppenz P, Els‐Heindl S, Beck‐Sickinger AG. Identification and stabilization of a highly selective gastrin‐releasing peptide receptor agonist. J Pept Sci 2019; 25:e3224. [DOI: 10.1002/psc.3224] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Paul Hoppenz
- Institute of BiochemistryLeipzig University Leipzig Germany
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Okarvi SM, AlJammaz I. A convenient and efficient total solid-phase synthesis of DOTA-functionalized tumor-targeting peptides for PET imaging of cancer. EJNMMI Res 2019; 9:88. [PMID: 31502101 PMCID: PMC6733935 DOI: 10.1186/s13550-019-0539-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/17/2019] [Indexed: 11/20/2022] Open
Abstract
Introduction An efficient and cost-effective synthesis of the metal chelating agents that couple to tumor-targeting peptides is required to enhance the process of preclinical research toward the clinical translation of molecular imaging agents. DOTA is one of the most widely used macrocyclic ligands for the development of new metal-based imaging and therapeutic agents owing to its ability to form stable and inert complexes under physiological conditions. Although solid-phase synthesis compatible DOTA-tris-(t-Bu ester) is a commercial product, it is expensive and contain chemical impurities. There is a need to explore new and cost-effective methods for the preparation of metal chelating agents, i.e., DOTA, directly on solid support to facilitate rapid, cost-effective, and high purity preparation of DOTA-linked peptides for imaging and therapy. In the present study, we describe a facile synthetic strategy of DOTA preparation and its linkage to peptides directly on solid-phase support. Methods Bombesin (BN) peptides were functionalized with DOTA chelator prepared from cyclen precursor on solid-phase and from commercial DOTA-tris and radiolabeled with 68Ga. In vitro BN/GRP receptor binding affinities of the corresponding radiolabeled peptides were determined by saturation binding assays on human breast MDA-MB-231, MCF7, T47D, and PC3 prostate cancer cells. Pharmacokinetics were studied in Balb/c mice and in vivo tumor targeting in MDA-MB-231 tumor-bearing nude mice. Results DOTA was prepared successfully from cyclen on solid-phase support, linked specifically to BN peptides and resultant DOTA-coupled peptides were radiolabeled efficiently with 68Ga. The binding affinities of all the six BN peptides were comparable and in the low nanomolar range. All 68Ga-labeled peptides showed high metabolic stability in plasma. These radiopeptides exhibited rapid pharmacokinetics in Balb/c mice with excretion mainly through the urinary system. In nude mice, MDA-MB-231 tumor uptake profiles were slightly different; the BN peptide with Ahx spacer and linked to DOTA through cyclen exhibited higher tumor uptake (2.32% ID/g at 1 h post-injection) than other radiolabeled BN peptides investigated in this study. The same leading BN peptide also displayed favorable pharmacokinetic profile in Balb/c mice. The PET images clearly visualized the MDA-MB-231 tumor. Conclusions DOTA prepared from cyclen on solid-phase support showed comparable potency and efficiency to DOTA-tris in both in vitro and in vivo evaluation. The synthetic methodology described here allows versatile, site-specific introduction of DOTA into peptides to facilitate the development of DOTA-linked molecular imaging and therapy agents for clinical translation.
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Affiliation(s)
- Subhani M Okarvi
- Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, MBC-03, P.O. Box 3354, Riyadh, 11211, Saudi Arabia.
| | - Ibrahim AlJammaz
- Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, MBC-03, P.O. Box 3354, Riyadh, 11211, Saudi Arabia
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Gibbens-Bandala B, Morales-Avila E, Ferro-Flores G, Santos-Cuevas C, Meléndez-Alafort L, Trujillo-Nolasco M, Ocampo-García B. 177Lu-Bombesin-PLGA (paclitaxel): A targeted controlled-release nanomedicine for bimodal therapy of breast cancer. Mater Sci Eng C Mater Biol Appl 2019; 105:110043. [PMID: 31546458 DOI: 10.1016/j.msec.2019.110043] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/26/2019] [Accepted: 07/31/2019] [Indexed: 12/28/2022]
Abstract
The gastrin-releasing peptide receptor (GRPr) is overexpressed in >75% of breast cancers. 177Lu-Bombesin (177Lu-BN) has demonstrated the ability to target GRPr and facilitate efficient delivery of therapeutic radiation doses to malignant cells. Poly(d,l‑lactide‑co‑glycolide) acid (PLGA) nanoparticles can work as smart drug controlled-release systems activated through pH changes. Considering that paclitaxel (PTX) is a first-line drug for cancer treatment, this work aimed to synthesize and chemically characterize a novel polymeric PTX-loaded nanosystem with grafted 177Lu-BN and to evaluate its performance as a targeted controlled-release nanomedicine for concomitant radiotherapy and chemotherapy of breast cancer. PLGA(PTX) nanoparticles were synthesized using the single emulsification-solvent evaporation method with PVA as a stabilizer in the presence of PTX. Thereafter, the activation of PLGA carboxylic groups for BN attachment through the Lys1-amine group was performed. Results of the chemical characterization by FT-IR, DLS, HPLC and SEM/TEM demonstrated the successful synthesis of BN-PLGA(PTX) with a hydrodynamic diameter of 163.54 ± 33.25 nm. The entrapment efficiency of paclitaxel was 92.8 ± 3.6%. The nanosystem showed an adequate controlled release of the anticancer drug, which increased significantly due to the pH change from neutral (pH = 7.4) to acidic conditions (pH = 5.3). After labeling with 177Lu and purification by ultrafiltration, 177Lu-BN-PLGA(PTX) was obtained with a radiochemical purity of 99 ± 1%. In vitro and in vivo studies using MDA-MB-231 breast cancer cells (GRPr-positive) demonstrated a 177Lu-BN-PLGA(PTX) specific uptake and a significantly higher cytotoxic effect for the radiolabeled nanosystem than the unlabeled BN-PLGA(PTX) nanoparticles. Using a pulmonary micrometastasis MDA-MB-231 model, the added value of 177Lu-BN-PLGA(PTX) for tumor imaging was confirmed. The 177Lu-BN-PLGA(PTX) nanomedicine is suitable as a targeted paclitaxel delivery system with concomitant radiotherapeutic effect for the treatment of GRPr-positive breast cancer.
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Affiliation(s)
- Brenda Gibbens-Bandala
- Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, Ocoyoacac, Estado de México 52750, Mexico; Facultad de Química, Universidad Autónoma del Estado de México, Paseo Tollocan S/N, Toluca, Estado de México 50180, Mexico
| | - Enrique Morales-Avila
- Facultad de Química, Universidad Autónoma del Estado de México, Paseo Tollocan S/N, Toluca, Estado de México 50180, Mexico
| | - Guillermina Ferro-Flores
- Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, Ocoyoacac, Estado de México 52750, Mexico
| | - Clara Santos-Cuevas
- Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, Ocoyoacac, Estado de México 52750, Mexico
| | | | - Maydelid Trujillo-Nolasco
- Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, Ocoyoacac, Estado de México 52750, Mexico; Facultad de Química, Universidad Autónoma del Estado de México, Paseo Tollocan S/N, Toluca, Estado de México 50180, Mexico
| | - Blanca Ocampo-García
- Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, Ocoyoacac, Estado de México 52750, Mexico.
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Liolios C, Buchmuller B, Bauder-Wüst U, Schäfer M, Leotta K, Haberkorn U, Eder M, Kopka K. Monomeric and Dimeric 68Ga-Labeled Bombesin Analogues for Positron Emission Tomography (PET) Imaging of Tumors Expressing Gastrin-Releasing Peptide Receptors (GRPrs). J Med Chem 2018; 61:2062-2074. [PMID: 29432691 DOI: 10.1021/acs.jmedchem.7b01856] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The GRPr, highly expressed in prostate PCa and breast cancer BCa, is a promising target for the development of new PET radiotracers. The chelator HBED-CC ( N, N'-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine- N, N'-diacetic acid) was coupled to the bombesin peptides: HBED-C-BN(2-14) 1, HBED-CC-PEG2-[d-Tyr6,β-Ala11,Thi13,Nle14]-BN(6-14) 2, HBED-CC-Y-[d-Phe6,Sta13,Leu14]-BN(6-14) (Y = 4-amino-1-carboxymethylpiperidine) 3, and HBED-CC-{PEG2-Y-[d-Phe6,Sta13,Leu14]-BN(6-14)}2 4 (homodimer). Compounds 1-4 presented high binding affinities for GRPr (T47D, 0.56-3.51 nM; PC-3, 2.12-4.68 nM). In PC-3 and T47D cells, agonists [68Ga]1 and [68Ga]2 were mainly internalized while antagonists [68Ga]3 and [68Ga]4 were surface bound. Cell-related radioactivity reached a maximum after 45 min, while tracer levels followed GRPr expression (PC-3 > T47D > LNCaP > MDA-MB-231). [68Ga]4 showed the highest cell-bound radioactivity (PC-3 and T47D). In vivo, tumor (PC-3) targeting for [68Ga]3 and [68Ga]4 increased over time, with dynamic μPET showing clearer tumors images at later time points. [68Ga]3 and [68Ga]4 can be considered suitable PET tracers for imaging PCa and BCa expressing GRPr.
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Affiliation(s)
| | | | | | | | | | - Uwe Haberkorn
- Department of Nuclear Medicine , University of Heidelberg , Im Neuenheimer Feld 400 , 69120 Heidelberg , Germany
| | - Matthias Eder
- Division of Radiopharmaceutical Development, German Cancer Consortium (DKTK) Freiburg, and Department of Nuclear Medicine, Faculty of Medicine, Medical Center, University of Freiburg, Hugstetter Straße 55 , 79106 Freiburg , Germany
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Kaloudi A, Lymperis E, Giarika A, Dalm S, Orlandi F, Barbato D, Tedesco M, Maina T, de Jong M, Nock BA. NeoBOMB1, a GRPR-Antagonist for Breast Cancer Theragnostics: First Results of a Preclinical Study with [ 67Ga]NeoBOMB1 in T-47D Cells and Tumor-Bearing Mice. Molecules 2017; 22:E1950. [PMID: 29137110 DOI: 10.3390/molecules22111950] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/06/2017] [Accepted: 11/08/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The GRPR-antagonist-based radioligands [67/68Ga/111In/177Lu]NeoBOMB1 have shown excellent theragnostic profiles in preclinical prostate cancer models, while [68Ga]NeoBOMB1 effectively visualized prostate cancer lesions in patients. We were further interested to explore the theragnostic potential of NeoBOMB1 in GRPR-positive mammary carcinoma, by first studying [67Ga]NeoBOMB1 in breast cancer models; Methods: We investigated the profile of [67Ga]NeoBOMB1, a [68Ga]NeoBOMB1 surrogate, in GRPR-expressing T-47D cells and animal models; Results: NeoBOMB1 (IC50s of 2.2 ± 0.2 nM) and [natGa]NeoBOMB1 (IC50s of 2.5 ± 0.2 nM) exhibited high affinity for the GRPR. At 37 °C [67Ga]NeoBOMB1 strongly bound to the T-47D cell-membrane (45.8 ± 0.4% at 2 h), internalizing poorly, as was expected for a radioantagonist. [67Ga]NeoBOMB1 was detected >90% intact in peripheral mouse blood at 30 min pi. In mice bearing T-47D xenografts, [67Ga]NeoBOMB1 specifically localized in the tumor (8.68 ± 2.9% ID/g vs. 0.6 ± 0.1% ID/g during GRPR-blockade at 4 h pi). The unfavorably high pancreatic uptake could be considerably reduced (206.29 ± 17.35% ID/g to 42.46 ± 1.31% ID/g at 4 h pi) by increasing the NeoBOMB1 dose from 10 pmol to 200 pmol, whereas tumor uptake remained unaffected. Notably, tumor values did not decline from 1 to 24 h pi; Conclusions: [67Ga]NeoBOMB1 can successfully target GRPR-positive breast cancer in animals with excellent prospects for clinical translation.
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Morgat C, MacGrogan G, Brouste V, Vélasco V, Sévenet N, Bonnefoi H, Fernandez P, Debled M, Hindié E. Expression of Gastrin-Releasing Peptide Receptor in Breast Cancer and Its Association with Pathologic, Biologic, and Clinical Parameters: A Study of 1,432 Primary Tumors. J Nucl Med 2017; 58:1401-1407. [DOI: 10.2967/jnumed.116.188011] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 02/17/2017] [Indexed: 12/15/2022] Open
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Elshafae SM, Hassan BB, Supsavhad W, Dirksen WP, Camiener RY, Ding H, Tweedle MF, Rosol TJ. Gastrin-releasing peptide receptor (GRPr) promotes EMT, growth, and invasion in canine prostate cancer. Prostate 2016; 76:796-809. [PMID: 26939805 PMCID: PMC5867904 DOI: 10.1002/pros.23154] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/05/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND The gastrin-releasing peptide receptor (GRPr) is upregulated in early and late-stage human prostate cancer (PCa) and other solid tumors of the mammary gland, lung, head and neck, colon, uterus, ovary, and kidney. However, little is known about its role in prostate cancer. This study examined the effects of a heterologous GRPr agonist, bombesin (BBN), on growth, motility, morphology, gene expression, and tumor phenotype of an osteoblastic canine prostate cancer cell line (Ace-1) in vitro and in vivo. METHODS The Ace-1 cells were stably transfected with the human GRPr and tumor cells were grown in vitro and as subcutaneous and intratibial tumors in nude mice. The effect of BBN was measured on cell proliferation, cell migration, tumor growth (using bioluminescence), tumor cell morphology, bone tumor phenotype, and epithelial-mesenchymal transition (EMT) and metastasis gene expression (quantitative RT-PCR). GRPr mRNA expression was measured in primary canine prostate cancers and normal prostate glands. RESULTS Bombesin (BBN) increased tumor cell proliferation and migration in vitro and tumor growth and invasion in vivo. BBN upregulated epithelial-to-mesenchymal transition (EMT) markers (TWIST, SNAIL, and SLUG mRNA) and downregulated epithelial markers (E-cadherin and β-catenin mRNA), and modified tumor cell morphology to a spindle cell phenotype. Blockade of GRPr upregulated E-cadherin and downregulated VIMENTIN and SNAIL mRNA. BBN altered the in vivo tumor phenotype in bone from an osteoblastic to osteolytic phenotype. Primary canine prostate cancers had increased GRPr mRNA expression compared to normal prostates. CONCLUSION These data demonstrated that the GRPr is important in prostate cancer growth and progression and targeting GRPr may be a promising strategy for treatment of prostate cancer. Prostate 76:796-809, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Said M. Elshafae
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
- Department of Pathology, Faculty of Veterinary Medicine, Benha University, Kalyubia, Egypt
| | - Bardes B. Hassan
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
- Department of Pathology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | | | - Wessel P. Dirksen
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
| | - Rachael Y. Camiener
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
| | - Haiming Ding
- Department of Radiology, Wexner Medical Center, The Wright Center for Innovation in Biomedical Imaging, The Ohio State University, Columbus, Ohio
| | - Michael F. Tweedle
- Department of Radiology, Wexner Medical Center, The Wright Center for Innovation in Biomedical Imaging, The Ohio State University, Columbus, Ohio
| | - Thomas J. Rosol
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
- Correspondence to: Dr. Thomas Rosol, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210.
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Haeck JC, Bol K, de Ridder CMA, Brunel L, Fehrentz JA, Martinez J, van Weerden WM, Bernsen MR, de Jong M, Veenland JF. Imaging heterogeneity of peptide delivery and binding in solid tumors using SPECT imaging and MRI. EJNMMI Res 2016; 6:3. [PMID: 26769345 PMCID: PMC4713394 DOI: 10.1186/s13550-016-0160-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 01/05/2016] [Indexed: 01/03/2023] Open
Abstract
Background As model system, a solid-tumor patient-derived xenograft (PDX) model characterized by high peptide receptor expression and histological tissue homogeneity was used to study radiopeptide targeting. In this solid-tumor model, high tumor uptake of targeting peptides was expected. However, in vivo SPECT images showed substantial heterogeneous radioactivity accumulation despite homogenous receptor distribution in the tumor xenografts as assessed by in vitro autoradiography. We hypothesized that delivery of peptide to the tumor cells is dictated by adequate local tumor perfusion. To study this relationship, sequential SPECT/CT and MRI were performed to assess the role of vascular functionality in radiopeptide accumulation. Methods High-resolution SPECT and dynamic contrast-enhanced (DCE)-MRI were acquired in six mice bearing PC295 PDX tumors expressing the gastrin-releasing peptide (GRP) receptor. Two hours prior to SPECT imaging, animals received 25 MBq 111In(DOTA-(βAla)2-JMV594) (25 pmol). Images were acquired using multipinhole SPECT/CT. Directly after SPECT imaging, MR images were acquired on a 7.0-T dedicated animal scanner. DCE-MR images were quantified using semi-quantitative and quantitative models. The DCE-MR and SPECT images were spatially aligned to compute the correlations between radioactivity and DCE-MRI-derived parameters over the tumor. Results Whereas histology, in vitro autoradiography, and multiple-weighted MRI scans all showed homogenous tissue characteristics, both SPECT and DCE-MRI showed heterogeneous distribution patterns throughout the tumor. The average Spearman’s correlation coefficient between SPECT and DCE-MRI ranged from 0.57 to 0.63 for the “exchange-related” DCE-MRI perfusion parameters. Conclusions A positive correlation was shown between exchange-related DCE-MRI perfusion parameters and the amount of radioactivity accumulated as measured by SPECT, demonstrating that vascular function was an important aspect of radiopeptide distribution in solid tumors. The combined use of SPECT and MRI added crucial information on the perfusion efficiency versus radiopeptide uptake in solid tumors and showed that functional tumor characteristics varied locally even when the tissue appeared homogenous on current standard assessment techniques. Electronic supplementary material The online version of this article (doi:10.1186/s13550-016-0160-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- J C Haeck
- Department of Radiology, Erasmus MC, Rotterdam, the Netherlands. .,Department of Medical Informatics, Erasmus MC, Rotterdam, the Netherlands. .,Department of Nuclear Medicine, Erasmus MC, Dr. Molewaterplein 50, 3015 GE, Rotterdam, the Netherlands.
| | - K Bol
- Department of Radiology, Erasmus MC, Rotterdam, the Netherlands.,Department of Medical Informatics, Erasmus MC, Rotterdam, the Netherlands.,Department of Nuclear Medicine, Erasmus MC, Dr. Molewaterplein 50, 3015 GE, Rotterdam, the Netherlands
| | - C M A de Ridder
- Department of Urology, Erasmus MC, Rotterdam, the Netherlands
| | - L Brunel
- IBMM, UMR 5247, CNRS, ENSCM, Faculté de Pharmacie, Université Montpellier, Montpellier, France
| | - J A Fehrentz
- IBMM, UMR 5247, CNRS, ENSCM, Faculté de Pharmacie, Université Montpellier, Montpellier, France
| | - J Martinez
- IBMM, UMR 5247, CNRS, ENSCM, Faculté de Pharmacie, Université Montpellier, Montpellier, France
| | - W M van Weerden
- Department of Urology, Erasmus MC, Rotterdam, the Netherlands
| | - M R Bernsen
- Department of Radiology, Erasmus MC, Rotterdam, the Netherlands.,Department of Nuclear Medicine, Erasmus MC, Dr. Molewaterplein 50, 3015 GE, Rotterdam, the Netherlands
| | - M de Jong
- Department of Radiology, Erasmus MC, Rotterdam, the Netherlands.,Department of Nuclear Medicine, Erasmus MC, Dr. Molewaterplein 50, 3015 GE, Rotterdam, the Netherlands
| | - J F Veenland
- Department of Radiology, Erasmus MC, Rotterdam, the Netherlands.,Department of Medical Informatics, Erasmus MC, Rotterdam, the Netherlands
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Saito H, Nakamachi T, Inoue K, Ikeda R, Kitamura K, Minamino N, Shioda S, Miyata A. Autocrine effects of neuromedin B stimulate the proliferation of rat primary osteoblasts. J Endocrinol 2013; 217:141-50. [PMID: 23428580 DOI: 10.1530/joe-12-0488] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neuromedin B (NMB) is a mammalian bombesin-like peptide that regulates exocrine/endocrine secretion, smooth muscle contraction, body temperature, and the proliferation of some cell types. Here, we show that mRNA encoding Nmb and its receptor (Nmbr) are expressed in rat bone tissue. Immunohistochemical analysis demonstrated that NMB and NMBR colocalize in osteoblasts, epiphyseal chondrocytes, and proliferative chondrocytes of growth plates from mouse hind limbs. Then, we investigated the effect of NMB on the proliferation of rat primary cultured osteoblasts. Proliferation assays and 5-bromo-2'-deoxyuridine incorporation assays demonstrated that NMB augments the cell number and enhances DNA synthesis in osteoblasts. Pretreatment with the NMBR antagonist BIM23127 inhibited NMB-induced cell proliferation and DNA synthesis. Western blot analysis showed that NMB activates ERK1/2 MAPK signaling in osteoblasts. Pretreatment with the MAPK/ERK kinase inhibitor U0126 attenuated NMB-induced cell proliferation and DNA synthesis. We also investigated the effects of molecules that contribute to osteoblast proliferation and differentiation on Nmb expression in osteoblasts. Real-time PCR analysis demonstrated that 17β-estradiol (E2) and transforming growth factor β1 increase and decrease Nmb mRNA expression levels respectively. Finally, proliferation assays revealed that the NMBR antagonist BIM23127 suppresses E2-induced osteoblast proliferation. These results suggest that NMB/NMBR signaling plays an autocrine or paracrine role in osteoblast proliferation and contributes to the regulation of bone formation.
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Affiliation(s)
- Hiroki Saito
- Department of Pharmacology, Graduate School of Medical and Dental Science, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
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Sayegh AI. The Role of Bombesin and Bombesin-Related Peptides in the Short-term Control of Food Intake. Progress in Molecular Biology and Translational Science 2013; 114:343-70. [DOI: 10.1016/b978-0-12-386933-3.00010-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Cornelio DB, DE Farias CB, Prusch DS, Heinen TE, Dos Santos RP, Abujamra AL, Schwartsmann G, Roesler R. Influence of GRPR and BDNF/TrkB signaling on the viability of breast and gynecologic cancer cells. Mol Clin Oncol 2012; 1:148-152. [PMID: 24649138 DOI: 10.3892/mco.2012.7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 08/01/2012] [Indexed: 12/14/2022] Open
Abstract
Neuropeptide and neurotrophin receptors are increasingly important molecular targets in cancer. Scientific findings indicate that compounds blocking gastrin-releasing peptide receptors (GRPR) or tropomyosin receptor kinase (Trk) receptors are likely to have antiproliferative activities against cancer cells. The present study aimed to demonstrate that, in contrast to previous findings, GRPR activation reduces, whereas its blockade increases the viability of breast, ovarian and cervical cancer cell lines. However, consistent with previous studies, Trk inhibition was demonstrated to reduce the viability of these cells. MCF-7 (breast), OVCAR-3 (ovarian) and HeLa (cervical) human cancer cell lines were treated with GRP, the GRPR antagonists RC-3095 and RC-3940-II, brain-derived neurotrophic factor (BDNF) and the Trk antagonist K252α. Cell viability was measured by the MTT assay. Expression of GRPR and BDNF was confirmed with reverse transcription-polymerase chain reaction (RT-PCR). GRP reduced, whereas RC-3940-II enhanced the viability of the three cell lines. Treatment with K252α inhibited the viability of the cell lines, while BDNF increased the viability of OVCAR-3 cells. The results supported the hypothesis that GRPR and BDNF/TrkB signaling regulates cancer cell viability. Most importantly, these findings are the first to demonstrate that GRPR blockade can stimulate, rather than inhibits the viability of breast and gynecologic cancer cell lines.
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Affiliation(s)
- Daniela B Cornelio
- Cancer Research Laboratory, University Hospital Research Center (CPE-HCPA)
| | | | - Débora S Prusch
- Cancer Research Laboratory, University Hospital Research Center (CPE-HCPA)
| | - Tiago E Heinen
- Cancer Research Laboratory, University Hospital Research Center (CPE-HCPA)
| | | | - Ana L Abujamra
- Cancer Research Laboratory, University Hospital Research Center (CPE-HCPA)
| | - Gilberto Schwartsmann
- Cancer Research Laboratory, University Hospital Research Center (CPE-HCPA); ; National Institute for Translational Medicine (INCT-TM); ; Department of Internal Medicine, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Rafael Roesler
- Cancer Research Laboratory, University Hospital Research Center (CPE-HCPA)
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Okarvi SM, Jammaz IA. Preparation and evaluation of bombesin peptide derivatives as potential tumor imaging agents: effects of structure and composition of amino acid sequence on in vitro and in vivo characteristics. Nucl Med Biol 2012; 39:795-804. [PMID: 22381782 DOI: 10.1016/j.nucmedbio.2012.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 12/28/2011] [Accepted: 01/09/2012] [Indexed: 12/01/2022]
Abstract
OBJECTIVES Among the many clinically relevant peptide receptor systems, bombesin (BN) receptors have attracted enormous attraction due to their overexpression in various frequently occurring human tumors including breast and prostate, thus making such receptors promising targets with radiolabeled BN analogs. The present study describes the preparation and evaluation of a series of new BN derivatives as potential tumor imaging agents. METHODS Several new BN derivatives with the common structure MAG(3)-X-BN(1-14 or 6-14), where X=Asp or Asp-Asp, were synthesized by solid-phase peptide synthesis. S-benzoylmercaptoacetic acid was incorporated at the end of synthesis via manual conjugation to yield MAG(3)-BN conjugates. Radiolabeling with (99m)Tc was accomplished by ligand exchange method. The receptor-binding affinity assays were performed in MDA-MB-231, MCF-7, T47-D and PC-3 cancer cell lines. In vivo biodistribution and clearance kinetics were assessed in Balb/c mice, and tumor targeting efficacy was determined in nude mice bearing breast tumor xenografts. RESULTS The peptides were prepared conveniently and radiolabeled efficiently with (99m)Tc (up to 95% labeling efficiency). In vitro cell binding assays demonstrated high affinity (values in the nanomolar range) of (99m)Tc peptides towards breast and prostate cancer cell lines. In addition, the radioconjugates displayed significant internalization (values ranged between 19% and 35%) in tumor cells. In vivo biodistribution and biokinetics are characterized by efficient clearance from the blood and variable degrees of excretion through the renal pathway. In vivo tumor targeting studies displayed variable uptake capacity of different BN derivatives, underlining the influence of specific amino acid sequence on tumor targeting profiles. Tumor uptake was always higher than the radioactivity in the blood and muscle, with good tumor retention and good tumor-to-blood and tumor-to-muscle ratios, indicating the potential of these agents for targeting tumors in vivo. CONCLUSIONS The combination of favorable in vitro and in vivo properties may render these BN peptides as potential candidates for targeting BN/GRP receptor-positive tumors. They deserve further evaluation to determine their real strength. The present data indeed provide useful information regarding peptide structure-pharmacologic activity relationship, which might be useful in designing and developing new BN-like peptides for efficient targeting of tumors in vivo.
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Affiliation(s)
- Subhani M Okarvi
- Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
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Park HJ, Kim SR, Kim MK, Choi KS, Jang HO, Yun I, Bae SK, Bae MK. Neuromedin B receptor antagonist suppresses tumor angiogenesis and tumor growth in vitro and in vivo. Cancer Lett 2011; 312:117-27. [PMID: 21908103 DOI: 10.1016/j.canlet.2011.08.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 08/05/2011] [Accepted: 08/09/2011] [Indexed: 11/29/2022]
Abstract
Neuromedin B (NMB), a member of the mammalian bombesin-like peptide family, and its receptor were aberrantly expressed in vascularized solid tumors. Here, the NMB receptor (NMB-R) antagonist PD168368 specifically inhibited both NMB-induced in vivo and in vitro angiogenesis. In addition, PD168368 showed growth inhibitory effects on MDA-MB-231 breast cancer cells by inducing cell cycle arrest and apoptosis. Furthermore, PD168368 effectively suppressed tumor growth in a xenograft model of breast tumor in vivo. Overall, NMB-R antagonist exhibited a significant antitumor activity by simultaneously inhibiting neovascularization and cancer cell growth, thereby suggesting that NMB-R could be a potential therapeutic target for cancer treatment.
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Affiliation(s)
- Hyun-Joo Park
- School of Dentistry, Pusan National University, Yangsan 626-870, South Korea
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Okarvi SM, Al Jammaz I. Synthesis and evaluation of a technetium-99m labeled cytotoxic bombesin peptide conjugate for targeting bombesin receptor-expressing tumors. Nucl Med Biol 2010; 37:277-88. [DOI: 10.1016/j.nucmedbio.2009.12.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/09/2009] [Accepted: 12/16/2009] [Indexed: 11/24/2022]
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Hoffman TJ, Smith CJ. True radiotracers: Cu-64 targeting vectors based upon bombesin peptide. Nucl Med Biol 2009; 36:579-85. [DOI: 10.1016/j.nucmedbio.2009.03.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 03/09/2009] [Accepted: 03/19/2009] [Indexed: 12/15/2022]
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Chevalier S, Aprikian A, Beauregard G, Defoy I, Nguyen L, Guenette R, Tenniswood M, Chapdelaine A. Action, localization and structure-function relationship of growth factors and their receptors in the prostate. ACTA ACUST UNITED AC 1996; 5:73-105. [DOI: 10.1017/s0962279900001265] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Whereas the direct action of sex steroids, namely of androgens, on prostate cell division was questioned as early as in the 1970s, and remains so, the interest in prostatic growth factors (GFs) is rather recent but has expanded tremendously in the last five years. This lag period can be partly explained by the fact that, at the time, androgen receptors had just been discovered, and newly developed hormonal regimens or strategies to treat patients with prostate carcinoma (PCa) or epithelioma had generated great enthusiasm and hopes in the medical and scientific community. Another point to consider was the difficulty in maintaining prostate tissues in organ cultures and the relative novelty of culturing prostate epithelial cells in monolayers. Failures of sex steroids to elicit a direct positive response on prostate cell divisionin vitro, as seenin vivo, were interpreted as resulting from inappropriate models or culture conditions. However, the increasing number of reports confirming the lack of mitogenic activity of sex steroidsin vitro, coupled with the powerful mitogenic activity of GFs displayed in other systems, the discovery of GF receptors (GF-Rs), and the elucidation of their signalling pathways showing sex steroid receptors as potential substrates of GF-activated protein kinases gradually led to an increased interest in the putative role of GFs in prostate physiopathology. Of utmost importance was the recognition that hormone refractiveness was responsible for PCa progression, and for the poor outcome of patients with advanced disease under endocrine therapies. This problem remains a major issue and it raises several key questions that need to be solved at the fundamental and clinical levels.
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Chao C, Ives K, Hellmich HL, Townsend CM, Hellmich MR. Gastrin-releasing peptide receptor in breast cancer mediates cellular migration and interleukin-8 expression. J Surg Res 2009; 156:26-31. [PMID: 19631337 DOI: 10.1016/j.jss.2009.03.072] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 02/05/2009] [Accepted: 03/23/2009] [Indexed: 11/30/2022]
Abstract
BACKGROUND Breast cancers aberrantly express gastrin-releasing peptide (GRP) hormone and its cognate receptor, gastrin-releasing peptide receptor (GRP-R). Experimental evidence suggests that bombesin (BBS), the pharmacological homologue of GRP, promotes breast cancer growth and progression. The contribution of GRP-R to other poor prognostic indicators in breast cancer, such as the expression of the EGF-R family of growth factors and hormone insensitivity, is unknown. MATERIALS AND METHODS Two estrogen receptor (ER)-negative breast cancer cell lines were used. MDA-MB-231 overexpress both EGFR and GRPR, whereas SK-BR-3 cells express EGF-R but lack GRP-R. Cellular proliferation was assessed by Coulter counter. Chemotactic migration was performed using Transwell chambers, and the migrated cells were quantified. Northern blot and real-time PCR were used to evaluate proangiogenic factor interleukin-8 (IL-8) mRNA expression. RESULTS In MDA-MB-231 cells, GRP-R and EGF-R synergize to regulate cell migration, IL-8 expression, but not cell proliferation. In SK-BR-3 cells, ectopic expression of GRP-R was sufficient to increase migration and IL-8 mRNA. CONCLUSIONS These data suggest relevant roles for GRP-R in ER-negative breast cancer progression. Future mechanistic studies to define the molecular role of GRP-R in breast cancer metastasis provide novel targets for the treatment of ER-negative breast cancers.
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Affiliation(s)
- Celia Chao
- Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555, USA
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Prasanphanich AF, Retzloff L, Lane SR, Nanda PK, Sieckman GL, Rold TL, Ma L, Figueroa SD, Sublett SV, Hoffman TJ, Smith CJ. In vitro and in vivo analysis of [(64)Cu-NO2A-8-Aoc-BBN(7-14)NH(2)]: a site-directed radiopharmaceutical for positron-emission tomography imaging of T-47D human breast cancer tumors. Nucl Med Biol 2009; 36:171-81. [PMID: 19217529 DOI: 10.1016/j.nucmedbio.2008.11.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 11/04/2008] [Accepted: 11/11/2008] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Human breast cancer, from which the T-47D cell line was derived, is known to overexpress the gastrin-releasing peptide receptor (GRPR) in some cases. Bombesin (BBN), an agonist for the GRPR, has been appended with a radionuclide capable of positron-emission tomography (PET) imaging and therapy. (64)Cu-NO2A-8-Aoc-BBN(7-14)NH(2) (NO2A=1,4,7-triazacyclononane-1,4-diacetate) has produced high-quality microPET images of GRPR-positive breast cancer xenografted tumors in mice. METHODS The imaging probe was synthesized by solid-phase peptide synthesis followed by manual conjugation of the 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) bifunctional chelator and radiolabeling in aqueous solution. The radiolabeled conjugate was subjected to in vitro and in vivo studies to determine its specificity for the GRPR and its pharmacokinetic profile. A T-47D tumor-bearing mouse was imaged with microPET/CT and microMRI imaging. RESULTS The (64)Cu-NO2A-8-Aoc-BBN(7-14)NH(2) targeting vector was determined to specifically localize in GRPR-positive tissue. Accumulation was observed in the tumor in sufficient quantities to allow for identification of tumors in microPET imaging procedures. For example, uptake and retention in T-47D xenografts at 1, 4 and 24 h were determined to be 2.27+/-0.08, 1.35+/-0.14 and 0.28+/-0.07 % ID/g, respectively. CONCLUSIONS The (64)Cu-NO2A-8-Aoc-BBN(7-14)NH(2) produced high-quality microPET images. The pharmacokinetic profile justifies investigation of this bioconjugate as a potentially useful diagnostic/therapeutic agent. Additionally, the bioconjugate would serve as a good starting point for modification and optimization of similar agents to maximize tumor uptake and minimize nontarget accumulation.
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Affiliation(s)
- Adam F Prasanphanich
- Department of Radiology, University of Missouri School of Medicine, Columbia, MO 65211, USA
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Ma L, Yu P, Veerendra B, Rold TL, Retzloff L, Prasanphanich A, Sieckman G, Hoffman TJ, Volkert WA, Smith CJ. In Vitro and In Vivo Evaluation of Alexa Fluor 680-Bombesin[7–14]NH2Peptide Conjugate, a High-Affinity Fluorescent Probe with High Selectivity for the Gastrin-Releasing Peptide Receptor. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Lixin Ma
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Ping Yu
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Bhadrasetty Veerendra
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Tammy L. Rold
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Lauren Retzloff
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Adam Prasanphanich
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Gary Sieckman
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Timothy J. Hoffman
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Wynn A. Volkert
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Charles J. Smith
- From the Departments of Radiology, Internal Medicine, and Medical Pharmacology and Physiology; The Radiopharmaceutical Sciences Institute; and International Institute of Nano and Molecular Medicine, University of Missouri-Columbia School of Medicine; Department of Physics and Astronomy, University of Missouri-Columbia; University of Missouri Research Reactor Center, University of Missouri-Columbia; and Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
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Patel O, Shulkes A, Baldwin GS. Gastrin-releasing peptide and cancer. Biochim Biophys Acta Rev Cancer 2006; 1766:23-41. [PMID: 16490321 DOI: 10.1016/j.bbcan.2006.01.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 01/09/2006] [Accepted: 01/10/2006] [Indexed: 02/07/2023]
Abstract
Over the past 20 years, abundant evidence has been collected to suggest that gastrin-releasing peptide (GRP) and its receptors play an important role in the development of a variety of cancers. In fact, the detection of GRP and the GRP receptor in small cell lung carcinoma (SCLC), and the demonstration that anti-GRP antibodies inhibited proliferation in SCLC cell lines, established GRP as the prototypical autocrine growth factor. All forms of GRP are generated by processing of a 125-amino acid prohormone; recent studies indicate that C-terminal amidation of GRP18-27 is not essential for bioactivity, and that peptides derived from residues 31 to 125 of the prohormone are present in normal tissue and in tumors. GRP receptors can be divided into four classes, all of which belong to the 7 transmembrane domain family and bind GRP and/or GRP analogues with affinities in the nM range. Over-expression of GRP and its receptors has been demonstrated at both the mRNA and protein level in many types of tumors including lung, prostate, breast, stomach, pancreas and colon. GRP has also been shown to act as a potent mitogen for cancer cells of diverse origin both in vitro and in animal models of carcinogenesis. Other actions of GRP relevant to carcinogenesis include effects on morphogenesis, angiogenesis, cell migration and cell adhesion. Future prospects for the use of radiolabelled and cytotoxic GRP analogues and antagonists for cancer diagnosis and therapy appear promising.
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Affiliation(s)
- Oneel Patel
- University of Melbourne, Department of Surgery, Austin Health, Studley Rd., Heidelberg, Victoria 3084, Australia
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Abstract
Growth factor receptors play critical roles in cancer cell proliferation and progression. A number of such receptors have been targeted for cancer treatment by either a monoclonal antibody or a specifically designed small molecule to inhibit the receptor function. Bombesin/gastrin-releasing peptide receptors (BN/GRP-Rs) are expressed in a variety of cancer cells and have limited distribution in normal human tissue. Inhibition of BN/GRP-Rs has been shown to block small cell lung cancer growth in vitro. Early phase clinical trials targeting human GRP-R showed anti-cancer activity. This review will focus on the study of the distribution of BN/GRP-Rs in normal and malignant tissues, and various approaches to targeting BN-GRP-Rs for cancer diagnosis and treatment.
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Affiliation(s)
- Jiehua Zhou
- Division of Blood and Marrow Transplantation, Department of Medicine and Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA 92093-0960, USA
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Matusiak D, Glover S, Nathaniel R, Matkowskyj K, Yang J, Benya RV. Neuromedin B and its receptor are mitogens in both normal and malignant epithelial cells lining the colon. Am J Physiol Gastrointest Liver Physiol 2005; 288:G718-28. [PMID: 15528253 DOI: 10.1152/ajpgi.00156.2004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Bombesin-like peptides are uniformly thought to act as mitogens in cancer. Yet by studying human tissues, we have recently shown that bombesin and its mammalian homologue gastrin-releasing peptide act as morphogens, promoting tumor differentiation when aberrantly upregulated in colon cancer. In contrast, little is known about the bombesin-like peptide neuromedin B (NMB) and its receptor (NMB-R) in the human gastrointestinal tract. We therefore studied their presence and function in normal and malignant human colonic epithelia. Anti-NMB monoclonal antibodies were made against keyhole limpet hemocyanin (KLH)-conjugated human NMB, whereas anti-NMB-R antibodies were raised in rabbits against KLH-conjugated peptides corresponding to the third intracellular loop and COOH-terminal tail of the receptor protein. NMB antibody recognized two bands at approximately 1.2 kDa and approximately 1.5 kDa. NMB-R antibodies recognized a band at 80 kDa (predicted 43 kDa); whereas treatment with the deglycosylating agent peptide-N-glycosidase generated bands at 65, 47, and 43 kDa. By immunohistochemistry, both NMB and NMB-R were expressed in normal and cancerous colonic epithelial tissues. In cancer, the amount of NMB was similar to that expressed by proliferating epithelial cells located within the crypt. In contrast, NMB-R expression was increased in cancer, with higher levels detected in better differentiated tumor cells. To assess NMB function, proliferation was determined in the nonmalignant human colonic epithelial cell line NCM-460 and in the colon cancer cell lines Caco-2 and HT-29. Exogenously added NMB was 50-100% more efficacious than gastrin-releasing peptide in causing tumor cell proliferation, whereas only NMB increased NCM-460 cell proliferation. These findings indicate that NMB and its receptor are coexpressed by proliferating cells in which they act in an autocrine fashion with similar and modest potency in both normal and malignant colonic epithelial cells.
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Affiliation(s)
- Damien Matusiak
- Dept. of Medicine, Univ. of Illinois at Chicago, 840 South Wood St. (M/C 716 Chicago, IL 60612, USA
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Lin KS, Luu A, Baidoo KE, Hashemzadeh-Gargari H, Chen MK, Brenneman K, Pili R, Pomper M, Carducci MA, Wagner HN. A New High Affinity Technetium-99m-Bombesin Analogue with Low Abdominal Accumulation. Bioconjug Chem 2004; 16:43-50. [PMID: 15656574 DOI: 10.1021/bc049820h] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
99mTc-labeled bombesin analogues have shown promise for noninvasive detection of many tumors that express bombesin (BN)/gastrin-releasing peptide (GRP) receptors. 99mTc-labeled peptides, however, have a tendency to accumulate in the liver and intestines due to hepatobiliary clearance as a result of the lipophilicity of the 99mTc chelates. This makes the imaging of lesions in the abdominal area difficult. In this study, we have synthesized a new high affinity 99mTc-labeled BN analogue, [DTPA1, Lys3(99mTc-Pm-DADT), Tyr4]BN, having a built-in pharmacokinetic modifier, DTPA, and labeled with 99mTc using a hydrophilic diaminedithiol chelator (Pm-DADT) to effect low hepatobiliary clearance. In vitro binding studies using human prostate cancer PC-3 cell membranes showed that the inhibition constant (Ki) for [DTPA1, Lys3(99Tc-Pm-DADT), Tyr4]BN was 4.1 +/- 1.4 nM. Biodistribution studies of [DTPA1, Lys3(99mTc-Pm-DADT), Tyr4]BN in normal mice showed very low accumulation of radioactivity in the liver and intestines (1.32 +/- 0.13 and 4.58 +/- 0.50% ID, 4 h postinjection, respectively). There was significant uptake (7.71 +/- 1.37% ID/g, 1 h postinjection) in the pancreas which expresses BN/GRP receptors. The uptake in the pancreas could be blocked by BN, partially blocked by neuromedin B, but not affected by somatostatin, indicating that the in vivo binding was BN/GRP receptor specific. Scintigraphic images showed specific, high contrast delineation of prostate cancer PC-3 xenografts in SCID mice. Thus, the new peptide has a great potential for imaging BN/GRP receptor-positive cancers located even in the abdomen.
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Affiliation(s)
- Kuo-Shyan Lin
- Department of Environmental Health Sciences, The Johns Hopkins Medical Institutions, 615 North Wolfe Street, Baltimore, Maryland 21205, USA
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28
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Abstract
The gastrin releasing peptide (GRP) receptor is becoming an increasingly attractive target for development of new radiolabeled peptides with diagnostic and therapeutic potential. The attractiveness of the GRP receptor as a target is based upon the functional expression of GRP receptors in several tumors of neuroendocrine origin including prostate, breast, and small cell lung cancer. This concise review outlines some of the efforts currently underway to develop new GRP receptor specific radiopharmaceuticals by employing a variety of radiometal chelation systems.
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Affiliation(s)
- C J Smith
- Radiopharmaceutical Sciences Institute, University of Missouri, Columbia, MO 65211, USA
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29
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Abstract
The overexpression of angiogenic factors such as vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and insulin-like growth factors (IGFs) plays a role in the migration and proliferation of endothelial cells in many cancers. Consequently, we investigated the effects of bombesin/gastrin-releasing peptide (GRP) antagonists on the expression of these angiogenic factors, the activities of matrix metalloproteinases (MMPs)-2 and -9, as well as the vascular density in MDA-MB-435 human oestrogen-independent breast cancers. Nude mice bearing orthotopic xenografts of MDA-MB-435 breast cancers were treated with bombesin/GRP antagonists for 6 weeks. Daily administration of 20 μg of RC-3095 or 10 μg of RC-3940-II significantly decreased the weight of MDA-MB-435 cancers by 44 and 53%, respectively. The inhibition of tumour growth was associated with a substantial reduction in the expression of mRNA and protein levels of basic fibroblast growth factor (bFGF), IGF-II and VEGF-A in the tumours. Both bombesin/GRP antagonists significantly decreased the vessel density of the tumours by about 37%, as shown by immunohistochemical detection of vessels on tumour slides. Gelatinolytic activities, detected by zymography, revealed a 33–46% reduction in MMP-9 activity after the treatment with either antagonist. In vitro studies revealed that MDA-MB-435 cells secrete bFGF, IGF-II and VEGF-A, and the secretion of these factors is inhibited by RC-3095 and RC-3940-II. This study demonstrates the antiangiogenic effect of bombesin/GRP antagonists RC-3095 and RC-3940-II, and underscores their possible therapeutic application for treatment of breast cancers.
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Affiliation(s)
- A M Bajo
- Endocrine Polypeptide and Cancer Institute, Veterans Affairs Medical Center, New Orleans, LA 70112-1262, USA
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30
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Drell TL, Joseph J, Lang K, Niggemann B, Zaenker KS, Entschladen F. Effects of neurotransmitters on the chemokinesis and chemotaxis of MDA-MB-468 human breast carcinoma cells. Breast Cancer Res Treat 2003; 80:63-70. [PMID: 12889599 DOI: 10.1023/a:1024491219366] [Citation(s) in RCA: 202] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Most patients suffering from breast carcinoma do not die due to the primary tumor but from the development of metastases. Active migration of cancer cells is a prerequisite for development of these metastases. We used time-lapse videomicroscopy and computer-assisted cell tracking of MDA-MB-468 human breast carcinoma cells, which were incorporated into a three-dimensional collagen matrix, in order to analyze the migratory activity of these cells in response to different neurotransmitters. Our results show that met-enkephalin, substance P, bombesin, dopamine, and norepinephrine have a stimulatory effect on the migration of the breast cancer cells; moreover, these cells show positive chemotaxis towards norepinephrine as was analyzed by the directionality and persistence on a single-cell basis. Gamma-aminobutyric acid (GABA) however has an inhibitory effect. Endorphin and leu-enkephalin, as well as histamin and acetylcholine, had no influence on the migratory activity of the cells. In summary, we provide evidence for a strong regulatory involvement of neurotransmitters in the regulation of breast cancer cell migration, which might provide the basis for the use of the pharmacological agonists and antagonists for the chemopreventive inhibition of metastasis development.
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Affiliation(s)
- T L Drell
- Institute for Immunology, Witten/Herdecke University, Witten, Germany
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Qu X, Xiao D, Weber HC. Biologic relevance of mammalian bombesin-like peptides and their receptors in human malignancies: . ACTA ACUST UNITED AC 2003; 10:60-71. [DOI: 10.1097/00060793-200302000-00010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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32
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Guo YS, Hellmich MR, Wen XD, Townsend CM. Activator protein-1 transcription factor mediates bombesin-stimulated cyclooxygenase-2 expression in intestinal epithelial cells. J Biol Chem 2001; 276:22941-7. [PMID: 11292836 DOI: 10.1074/jbc.m101801200] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Colorectal carcinogenesis is a complex, multistep process involving genetic alterations and progressive changes in signaling pathways regulating intestinal epithelial cell proliferation, differentiation, and apoptosis. Although cyclooxygenase-2 (COX-2), gastrin-releasing peptide (GRP), and its receptor, GRP-R, are not normally expressed by the epithelial cells lining the human colon, the levels of all three proteins are aberrantly overexpressed in premalignant adenomatous polyps and colorectal carcinomas of humans. Overexpression of these proteins is associated with altered epithelial cell growth, adhesion, and tumor cell invasiveness, both in vitro and in vivo; however, a mechanistic link between GRP-R-mediated signaling pathways and increased COX-2 overexpression has not been established. We report that bombesin, a homolog of GRP, potently stimulates the expression of COX-2 mRNA and protein as well as the release of prostaglandin E(2) from a rat intestinal epithelial cell line engineered to express GRP-R. Bombesin stimulation of COX-2 expression requires an increase in [Ca(2+)](i), activation of extracellular signal-regulated kinase (ERK)-1 and -2 and p38(MAPK), and increased activation and expression of the transcription factors Elk-1, ATF-2, c-Fos, and c-Jun. These data suggest that the expression of GRP-R in intestinal epithelial cells may play a role in carcinogenesis by stimulating COX-2 overexpression through an activator protein-1-dependent pathway.
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Affiliation(s)
- Y S Guo
- Departments of Surgery and Physiology and Biophysics, University of Texas Medical Branch, Galveston, Texas 77555, USA
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33
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Abstract
Gastrin-releasing peptide (GRP) and its receptor (GRP-R) are frequently expressed by cancers of the gastrointestinal tract, breast, lung, and prostate. Most studies have found that GRP and its amphibian homologue bombesin act to increase tumor cell proliferation, leading to the hypothesis that this peptide hormone is a mitogen important for the growth of various cancers. Yet GRP/GRP-R co-expression in cancer promotes the development of a well-differentiated phenotype; while multiple studies suggest that the presence of these 2 proteins confer a survival advantage. Along with recent reports showing that GRP and its receptor critically regulate aspects of colon and lung organogenesis, we argue that these proteins do not function primarily as mitogens when aberrantly expressed in cancer. Rather, we postulate that GRP/GRP-R are onco-fetal antigens that function as morphogens, with their effect on tumor cell proliferation being a component property of their ability to regulate differentiation. Thus aberrant GRP/GRP-R expression in cancer recapitulates, albeit in a dysfunctional manner, their normal role in development.
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Affiliation(s)
- J A Jensen
- Department of Medicine, University of Illinois at Chicago and Chicago Veterans Administration Medical Center (West Side Division), Chicago, Illinois 60612, USA
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34
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Abstract
The human gastrin-releasing peptide receptor (hGRP-R) is aberrantly expressed in cancers of the colon, lung and prostate and mediates signals of cellular proliferation. However, the underlying mechanisms of aberrant and/or activation of hGRP-R expression are unknown. Therefore, a genomic clone is identified, the hGRP-R gene is characterized, and the hGRP-R promoter is defined. The protein coding region is divided into three exons and exon/intron splice sites occur in the proximal 2nd and distal 3rd intracellular loops of the receptor molecule. The hGRP-R locus extends over more than 27 kb and is assigned to the chromosomal band Xp22 by fluorescence in situ hybridization. With primer extension experiments, we demonstrate two major transcription start sites in gastrointestinal and breast cancer cells, located 43 and 36 bp downstream of a TTTAAA motif which is identified 407 to 402 bp upstream of the ATG start codon. The hGRP-R is found most abundantly expressed in the normal human pancreas, where four gene-specific transcripts can be detected by Northern blot analysis, whereas only two transcripts are detected in the human stomach and, very weakly, in the adrenal cortex and the brain. In contrast, the human GRP-R is not expressed in the normal human colon, lung, and prostate. Steady state hGRP-R mRNA can also be detected in some cultured cells from breast, lung, and duodenal cancer. Robust hGRP-R promoter activity is demonstrated in a duodenal carcinoma cell line that natively expresses the functional hGRP-R. Truncation studies suggest a CRE motif, located 112 bp upstream of the major transcription start site, is required to confer basal hGRP-R promoter activity in duodenal cancer cells. These studies provide the necessary data to further elucidate molecular mechanisms of aberrant hGRP-R expression in human cancers.
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Affiliation(s)
- D Xiao
- Boston University School of Medicine, Section of Gastroenterology, 650 Albany Street, EBRC, 5th floor, Boston MA 02118, USA
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35
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Van de Wiele C, Dumont F, van Belle S, Slegers G, Peers SH, Dierckx RA. Is there a role for agonist gastrin-releasing peptide receptor radioligands in tumour imaging? Nucl Med Commun 2001; 22:5-15. [PMID: 11233552 DOI: 10.1097/00006231-200101000-00002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Gastrin-releasing peptide (GRP) has been shown to be a tumour growth stimulating agent for a number of normal and human cancer cell lines. The tumour growth effect is a direct result of GRP binding to membrane G-protein coupled GRP receptors (GRP-R) on the cell surface. Available data on the role of GRP and GRP-R in human lung, prostate, breast, colorectal and gastric carcinoma are reviewed and it is suggested that radiolabelled agonists are preferable to antagonists for imaging and therapy as they appear to be internalised, yielding a higher target/background ratio. The use of rhenium or indium radiolabels for therapy may provide a new approach to GRP/bombesin expressing tumours.
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Affiliation(s)
- C Van de Wiele
- Division of Nuclear Medicine, University Hospital Ghent, Belgium.
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36
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Kahán Z, Sun B, Schally AV, Arencibia JM, Cai RZ, Groot K, Halmos G. Inhibition of growth of MDA-MB-468 estrogen-independent human breast carcinoma by bombesin/gastrin-releasing peptide antagonists RC-3095 and RC-3940-II. Cancer 2000; 88:1384-92. [PMID: 10717621 DOI: 10.1002/(sici)1097-0142(20000315)88:6<1384::aid-cncr16>3.0.co;2-q] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The growth of breast carcinoma is promoted by autocrine growth factors such as the bombesin (BN)-like peptides and epidermal growth factor (EGF). The stimulatory action of BN-like peptides can be blocked by the use of BN/gastrin-releasing peptide (GRP) antagonists. METHODS The authors investigated the effects of synthetic BN/GRP antagonists RC-3095 and RC-3940-II on tumor growth and the expression of mRNA for EGF receptors and three BN receptor subtypes in MDA-MB-468 human breast carcinoma. Athymic nude mice with xenografts of MDA-MB-468 human breast carcinoma were injected subcutaneously for 6 weeks with RC-3940-II at doses of 20 or 40 microg/day. In another study, the effects of RC-3940-II and RC-3095 were compared. RESULTS RC-3940-II caused a significant and dose-dependent growth inhibition of MDA-MB-468 tumors in nude mice; therapy with either dose of RC-3940-II significantly (P<0.01) reduced the mean final tumor volume and weight compared with controls. RC-3940-II induced a persistent regression of > 50% of all tumors. One of 3 tumors treated with 20 microg of RC-3940-II and 3 of 5 tumors treated with 40 microg were found to have regressed completely by the end of the study. When RC-3940-II and RC-3095 were compared at the dose of 20 microg/day, both powerfully suppressed growth of MDA-MB-468 tumors, with RC-3940-II causing a complete regression of 2 tumors and RC-3095 a complete regression of 1 tumor. Receptor analyses of untreated MDA-MB-468 tumors revealed an overexpression of EGF receptors and two classes of binding sites for BN/GRP. mRNAs for receptors of GRP, neuromedin B, and BN receptor subtype-3 were detected by reverse transcriptase-polymerase chain reaction. CONCLUSIONS A virtual arrest of growth or regression of MDA-MB-468 human breast carcinoma after therapy with RC-3940-II and RC-3095 indicates that these BN/GRP antagonists could provide a new treatment modality for breast tumors expressing BN and EGF receptors.
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MESH Headings
- Animals
- Antineoplastic Agents/administration & dosage
- Antineoplastic Agents/therapeutic use
- Bombesin/administration & dosage
- Bombesin/analogs & derivatives
- Bombesin/antagonists & inhibitors
- Bombesin/therapeutic use
- Breast Neoplasms/drug therapy
- Breast Neoplasms/pathology
- Carcinoma/drug therapy
- Carcinoma/pathology
- Dose-Response Relationship, Drug
- ErbB Receptors/drug effects
- ErbB Receptors/genetics
- Female
- Gastrin-Releasing Peptide/antagonists & inhibitors
- Gene Expression Regulation, Neoplastic/drug effects
- Humans
- Injections, Subcutaneous
- Mice
- Mice, Nude
- Neoplasm Transplantation
- Neurokinin B/analogs & derivatives
- Neurokinin B/drug effects
- Peptide Fragments/administration & dosage
- Peptide Fragments/therapeutic use
- Polymerase Chain Reaction
- RNA, Messenger/drug effects
- Receptors, Bombesin/classification
- Receptors, Bombesin/drug effects
- Receptors, Bombesin/genetics
- Remission Induction
- Transplantation, Heterologous
- Tumor Cells, Cultured
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Affiliation(s)
- Z Kahán
- Endocrine, Polypeptide, and Cancer Institute, Veterans Affairs Medical Center, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
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Shriver SP, Bourdeau HA, Gubish CT, Tirpak DL, Davis AL, Luketich JD, Siegfried JM. Sex-specific expression of gastrin-releasing peptide receptor: relationship to smoking history and risk of lung cancer. J Natl Cancer Inst 2000; 92:24-33. [PMID: 10620630 DOI: 10.1093/jnci/92.1.24] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Activation of gastrin-releasing peptide receptor (GRPR) in human airways has been associated with a proliferative response of bronchial cells to gastrin-releasing peptide and with long-term tobacco use. The GRPR gene is located on the X chromosome and escapes X-chromosome inactivation, which occurs in females. Increasing evidence demonstrates that women are more susceptible than men to tobacco carcinogenesis. We hypothesized that the susceptibility of women to the effects of tobacco may be associated with airway expression of GRPR. METHODS We analyzed GRPR messenger RNA (mRNA) expression in lung tissues and cultured airway cells from 78 individuals (40 males and 38 females) and in lung fibroblasts exposed to nicotine in vitro. Nicotinic acetylcholine receptors in airway cells were assayed by use of radioactively labeled nicotine and nicotine antagonists. A polymorphism in exon 2 of the GRPR gene was used to detect allele-specific GRPR mRNA expression in some individuals. Statistical tests were two-sided. RESULTS GRPR mRNA expression was detected in airway cells and tissues of more female than male nonsmokers (55% versus 0%) and short-term smokers (1-25 pack-years [pack-years = number of packs of cigarettes smoked per day multiplied by the number of years of smoking]) (75% versus 20%) (P =.018 for nonsmoking and short-term smoking females versus nonsmoking and short-term smoking males). Female smokers exhibited expression of GRPR mRNA at a lower mean pack-year exposure than male smokers (37.4 pack-years versus 56.3 pack-years; P =.037). Lung fibroblasts and bronchial epithelial cells exhibited high-affinity, saturable nicotinic acetylcholine-binding sites. Expression of GRPR mRNA in lung fibroblasts was elevated following exposure to nicotine. CONCLUSIONS Our results suggest that the GRPR gene is expressed more frequently in women than in men in the absence of smoking and that expression of this gene is activated earlier in women in response to tobacco exposure. The presence of two expressed copies of the GRPR gene in females may be a factor in the increased susceptibility of women to tobacco-induced lung cancer.
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Affiliation(s)
- S P Shriver
- Department of Pharmacology, Lung Cancer Program, University of Pittsburgh Cancer Institute, PA, USA.
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38
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Abstract
The regulatory peptide gastrin-releasing peptide (GRP) may play a role in human cancer as a stimulatory growth factor. To understand the potential role of GRP in human breast cancer, we have evaluated GRP receptor expression in human non-neoplastic and neoplastic breast tissues and in axillary lymph node metastases, using in vitro receptor autoradiography on tissue sections with [(125)I]Tyr(4)-bombesin and with [(125)I]D-Tyr(6), beta Ala(11), Phe(13), Nle(14)-bombesin(6-14) as radioligands. GRP receptors were detected, often in high density, in neoplastic epithelial mammary cells in 29 of 46 invasive ductal carcinomas, in 11 of 17 ductal carcinomas in situ, in 1 of 4 invasive lobular carcinomas, in 1 of 2 lobular carcinomas in situ, and in 1 mucinous and 1 tubular carcinoma. A heterogeneous GRP receptor distribution was found in the neoplastic tissue samples in 32 of 52 cases with invasive carcinoma and 12 of 19 cases with carcinoma in situ. The lymph node metastases (n = 33) from those primary carcinomas expressing GRP receptors were all positive, whereas surrounding lymphoreticular tissue was negative. GRP receptors were also present in high density but with heterogeneous distribution in ducts and lobules from all available breast tissue samples (n = 23). All of the receptors corresponded to the GRP receptor subtype of bombesin receptors, having high affinity for GRP and bombesin and lower affinity for neuromedin B. All tissues expressing GRP receptors were identified similarly with both radioligands. These data describe not only a high percentage of GRP receptor-positive neoplastic breast tissues but also for the first time a ubiquitous GRP receptor expression in nonneoplastic human breast tissue. Apart from suggesting a role of GRP in breast physiology, these data represent the molecular basis for potential clinical applications of GRP analogs such as GRP receptor scintigraphy, radiotherapy, or chemotherapy.
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Affiliation(s)
- M Gugger
- Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, Berne, Switzerland
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39
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Carroll RE, Matkowskyj KA, Chakrabarti S, McDonald TJ, Benya RV. Aberrant expression of gastrin-releasing peptide and its receptor by well-differentiated colon cancers in humans. Am J Physiol 1999; 276:G655-65. [PMID: 10070042 DOI: 10.1152/ajpgi.1999.276.3.g655] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Epithelial cells lining the adult human colon do not normally express gastrin-releasing peptide (GRP) or its receptor (GRPR). In contrast, approximately one-third of human colon cancers and cancer cell lines have been shown to express GRP-binding sites. Because GRPR activation causes the proliferation of many cancer cell lines, GRP has been presumed to act as a clinically significant growth factor. Yet GRP has not been shown to be expressed by colon cancers in humans nor has the effect of GRP and/or GRPR coexpression on tumor behavior been investigated. We therefore determined GRP and GRPR expression by immunohistochemistry in 50 randomly selected colon cancers resected between 1980 and 1997, all 37 associated lymph node and liver metastases, and 20 polyps. Tumor sections studied were those that contained the margin and adjacent nonmalignant epithelium. Overall, 84% of cancers aberrantly expressed GRP or GRPR, with 62% expressing both ligand and receptor, whereas expression was not observed in adjacent normal epithelium. Consistent with the previously established mitogenic capabilities of GRP, tissues coexpressing GRP and GRPR were more likely to express proliferating cell nuclear antigen than tissues not expressing both ligand and receptor. Yet GRP/GRPR coexpression was seen with equal frequency in stage A as in stage D cancers and was only detected in 1 in 37 metastases. Furthermore, Kaplan-Meier analysis did not reveal any difference in patient survival between those whose tumors did or did not express GRP/GRPR. In contrast, GRP/GRPR coexpression was found in all well-differentiated tumor regions, whereas poorly differentiated tissues never coexpressed GRP/GRPR. Overall, these data indicate that, although GRP is a mitogen, it is not a clinically significant growth factor in human colon cancers. Rather, the strong association of GRP/GRPR coexpression with tumor differentiation raises the possibility that these proteins primarily act in vivo as morphogens.
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Affiliation(s)
- R E Carroll
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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40
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Abstract
We have investigated the production, growth and inactivation of gastrin-releasing peptide (GRP)-like peptides in human breast cancer cell lines. Radioimmunoassay detected GRP-like immunoreactivity (GRP-LI) in T47D breast cancer cells but not in the conditioned medium, indicating rapid clearance. No GRP-LI was found in the ZR-75-1 or MDA-MB-436 cells or their conditioned medium. High-performance liquid chromatography (HPLC) analysis of the GRP-LI in the T47D cells revealed a major peak, which co-eluted with GRP(18-27), and a minor more hydrophilic peak. In vitro stimulation of T47D cell growth by bombesin (BN) was enhanced to 138% of control levels (bombesin alone) by the addition of the selective endopeptidase EC 3.4.24.11 inhibitor phosphoramidon (0.1 ng ml(-1)). Fluorogenic analysis using whole cells confirmed low levels of this phosphoramidon-sensitive enzyme on the T47D cells. This enzyme, previously unreported in human breast cancer cells, significantly modulates both T47D growth and its response to BN-induced growth.
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Affiliation(s)
- D M Burns
- School of Biomedical Sciences, University of Ulster at Jordanstown, Newtownabbey, Co. Antrim, Northern Ireland
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41
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Abstract
Previously, we have observed that the expression of the neuropeptides bombesin (BN-), the mammalian counterpart being gastrin-releasing peptide (GRP), and substance P (SP) in intact normal tissues, such as salivary and laryngeal glands, increases in response to irradiation. In the present study, the aim was to evaluate whether irradiation can have effects on individual cells that normally synthesize neuropeptides. In addition, since these neuropeptides are potentially mitogenic, we studied tumor cells. Therefore, the estrogen receptor-negative human breast cancer cell line MDA-MB-231 and its subline, with acquired doxorubicin resistance, MDA-MB-231 Dox were examined before irradiation and 4, 10, and 15 days after irradiation with 4 Gy (195 kV, 2 Gy fractions with 4 hours interval). Potential dose related changes were studied by delivering single doses of 2 or 9 Gy with the same technique. Immunohistochemical and radioimmunoassay (RIA) methods were used for detection of the SP and BN/GRP. Before, and at all time points following irradiation, a subpopulation in both cell lines displayed an intense immunostaining of SP and BN/GRP. A partial reorganization of the immunoreactive material was observed 10 days after irradiation. The RIA-analyses displayed signs of a dose-related increase, and a time-dependent transient and significant increase in the content of both peptides. The pattern of changes differed between the two peptides, and was especially pronounced in the doxorubicin resistant cells with regard to SP. Another neuropeptide, calcitonin gene related peptide (CGRP), was not detected in the cells used. The results suggest that irradiation has effects on a population of cultured neuropeptide-synthesizing cells. The occurrence and the specific changes obtained in the levels of neuropeptides, in response to irradiation, might imply an importance in the growth of breast cancer cells and in explaining repair processes following irradiation.
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Affiliation(s)
- Y Aalto
- Department of Oncology, Umeå University, Sweden
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42
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Ferris HA, Carroll RE, Rasenick MM, Benya RV. Constitutive activation of the gastrin-releasing peptide receptor expressed by the nonmalignant human colon epithelial cell line NCM460. J Clin Invest 1997; 100:2530-7. [PMID: 9366567 PMCID: PMC508453 DOI: 10.1172/jci119795] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Gastrin-releasing peptide (GRP) causes multiple effects in humans by activating a specific heptaspanning receptor. Within the gastrointestinal tract, GRP receptors (GRP-R) are not normally expressed by mucosal epithelial cells except for those lining the gastric antrum. In contrast, recent studies have shown that up to 40% of resected colon cancers aberrantly express this receptor. This is important because the GRP-R can cause the proliferation of many, but not all, tissues in which it is expressed. Since GRP and other agonists are not known to exist in the colonic lumen, it has not been clear how or even if GRP-R expression in colon cancer contributes to cell proliferation. To evaluate the functional consequence of GRP-R expression on colonic epithelium, we transfected the recently isolated nonmalignant human colon epithelial cell line NCM460 with the cDNA for this receptor. All NCM460 cell lines expressing varying numbers of GRP-R bound selected agonists and antagonists indistinguishably from receptors expressed by other human tissues. Furthermore GRP-R-expressing transfected cell lines, but not wild-type NCM460 cells, proliferated independently of serum or other growth factors. Further evaluation revealed that GRP-R in these cells tonically stimulated G alpha q/11, resulting in increased phospholipase C activation. Since transfected cells do not secrete GRP, nor is their growth influenced by exposure to receptor-specific antagonists, these data indicate that GRP-R ectopically expressed by NCM460 cells are constitutively active. This report provides the first evidence of mutation-independent heptaspanning receptor constitutive activation resulting in cell proliferation, and identifies a potential mechanism whereby the GRP-R may act as an oncogene in human colon cancer.
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Affiliation(s)
- H A Ferris
- Department of Medicine, University of Illinois at Chicago, Illinois 60612, USA
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Garcia LJ, Pradhan TK, Weber HC, Moody TW, Jensen RT. The gastrin-releasing peptide receptor is differentially coupled to adenylate cyclase and phospholipase C in different tissues. Biochim Biophys Acta 1997; 1356:343-54. [PMID: 9194577 DOI: 10.1016/s0167-4889(97)00007-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent studies suggest that in some tissues GRP receptor activation can both stimulate phospholipase C and the adenylate cyclase pathway and that activation of the latter pathway may be important in mediating some of its well-described growth effects. However, other studies suggest GRP-R may not be coupled to adenylate cyclase. To investigate this possibility, in the present study we determined the coupling of the GRP receptors to each pathway in mouse, rat, and guinea pig pancreatic acini and compared it to that in mouse Swiss 3T3 cells and human SCLC cells, all of which possess well-characterized GRP receptors. Moreover, we tested the effect of PKC activation on the ability of GRP-related peptides to increase cAMP accumulation in these tissues. Changes in cAMP levels were determined with or without IBMX present, with or without forskolin, or both to amplify small increases in cAMP. In mouse, rat and guinea pig pancreatic acini, murine Swiss 3T3 cells and human SCLC cells, GRP-related peptides caused a 600%, 500%, 250%, 300% and 60% increase, respectively, in [3H]IP with 1-3 nM causing a half-maximal effect. In murine Swiss 3T3 cells, IBMX, forskolin, and IBMX plus forskolin caused a 300%, 3500% and 10500% increase in cAMP, respectively. GRP-related peptides and VIP caused an additional 70% increase in cAMP with GRP causing a half-maximal (EC50) increase in cAMP at 2.1 +/- 0.5 nM, which was not significantly different from the EC50 of 3.1 +/- 0.9 nM for increasing [3H]IP in these cells. GRP-related peptides did not stimulate increases in cAMP in mouse, rat or guinea pig pancreatic acini or in SCLC cells either alone, with IBMX or forskolin or both. However, in pancreatic acini IBMX, forskolin or both increased cAMP 3 to 8-, 10 to 500-, and 100 to 1000-fold increase and the addition of VIP caused an additional 20-, 2-, and 3-fold increase in cAMP in the different species. In mouse pancreatic acini with TPA alone or IBMX plus TPA, neither bombesin nor GRP increased cAMP. Furthermore, in mouse pancreatic acini, neither TPA nor TPA plus IBMX altered basal or VIP-stimulated increases in cAMP. In mouse Swiss 3T3 cells TPA significantly increased cAMP stimulated by Bn, GRP or VIP. These results demonstrated that GRP receptor activation in normal tissues from three different species and a human tumoral cell line do not result in adenylate cyclase activation, whereas in Swiss 3T3 cells it causes such activation. The results suggest that the difference in coupling to adenylate cyclase is likely at least partially due to a difference in coupling to an adenylate cyclase subtype whose activation is regulated by PKC. Therefore, the possible growth effects mediated by this receptor in different embryonic or tumoral cells through activation of adenylate cyclase are not likely to be an important intracellular pathway for these effects in normal tissues.
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Affiliation(s)
- L J Garcia
- Department of Physiology, University of Extremadura, Cáceres, Spain
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Tsuda T, Kusui T, Hou W, Benya RV, Akeson MA, Kroog GS, Battey JF, Jensen RT. Effect of gastrin-releasing peptide receptor number on receptor affinity, coupling, degradation, and modulation. Mol Pharmacol 1997; 51:721-32. [PMID: 9145910 DOI: 10.1124/mol.51.5.721] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The relationship between receptor number and agonist-induced intracellular responses has been well studied in receptors coupled to adenylate cyclase; however, for receptors coupled to phospholipase C (PLC), very little is known about the effect of receptor number on receptor-mediated processes. To explore this issue, we investigated the effect of the number of receptors for gastrin-releasing peptide (GRP) on ligand affinity and on the ability to activate intracellular messengers [PLC, tyrosine phosphorylation of p125 focal adhesion kinase (p125FAK)] and cause receptor modulation (internalization, desensitization, down-regulation) and ligand degradation. Three BALB 3T3 cell lines were made that stably expressed the gastrin-releasing peptide receptor (GRP-R) with receptor numbers varying by 280-fold (GRP-R-Low, GRP-R-Med, and GRP-R-Hi). Each cell line had the same affinity for agonist. The efficacy for bombesin to increase [3H]inositol phosphates but not tyrosine phosphorylation of p125FAK correlated well with receptor number. In contrast, the EC50 value for [3H]inositol phosphate generation for bombesin was the same in each cell line. Receptor number did not alter internalization. In the absence of protease inhibitors, there was an inverse correlation between receptor number and receptor down-regulation and desensitization. However, with protease inhibitors present, GRP-R-Med and GRP-R-Hi down-regulated significantly less than the GRP-R-Low. Similarly, GRP-R-Low desensitized significantly more than GRP-R-Med or GRP-R-Hi. GRP-R-Hi caused significantly greater ligand degradation than GRP-R-Low, and protease inhibitors completely inhibited degradation by GRP-R-Low and inhibited degradation by 70% for GRP-R-Hi. In conclusion, we show that for the PLC-coupled GRP-R, receptor number had little or no effect on binding affinity, potency for activating PLC, tyrosine phosphorylation of p125FAK, or extent of receptor internalization. In contrast, receptor number had an effect on ligand degradation, down-regulation, desensitization, and efficacy of PLC activation without altering the efficacy of tyrosine phosphorylation of p125FAK. These results demonstrate that the effect of receptor number differs for the different functions mediated by the GRP receptor and differs from that reported for adenylate cyclase-coupled receptors such as receptors mediating the action of adrenergic agents, secretin, and opioids.
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Affiliation(s)
- T Tsuda
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Affiliation(s)
- R de Castiglione
- Farmitalia Carlo Erba (now Pharmacia), Research Centre, Nerviano (MI), Italy
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46
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Affiliation(s)
- S R Preston
- Academic Unit of Surgery, St. James's University Hospital, Leeds, UK
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Fathi Z, Way JW, Corjay MH, Viallet J, Sausville EA, Battey JF. Bombesin receptor structure and expression in human lung carcinoma cell lines. J Cell Biochem Suppl 1996; 24:237-46. [PMID: 8806106 DOI: 10.1002/jcb.240630519] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mammalian bombesin-like peptides gastrin-releasing peptide (GRP) and neuromedin B (NMB) are regulatory neuropeptides involved in numerous physiologic processes, and have been implicated as autocrine and/or paracrine growth factors in human lung carcinoma. Three structurally and pharmacologically distinct bombesin receptor subtypes have been isolated and characterized: the gastrin releasing peptide receptor (GRP-R), the neuromedin B receptor (NMB-R), and bombesin receptor subtype-3 (BRS-3). The three receptors are structurally related, sharing about 50% amino acid identity. They are members of the G-protein coupled receptor superfamily with a seven predicted transmembrane segment topology characteristic of receptors in this family. The signal transduction pathway for GRP-R and NMB-R involves coupling to a pertussis-toxin insensitive G-protein, activation of phospholipase C (PLC), generation of inositol trisphosphate (IP3), release of intracellular calcium, and activation of protein kinase C. While all three bombesin receptors are activated by bombesin agonists, GRP-R, NMB-R, and BRS-3 have very different affinities for the mammalian bombesin-like peptides GRP and NMB, as well as bombesin receptor antagonists. The three bombesin receptor subtypes are expressed in an overlapping subset of human lung carcinoma cell lines. Any therapeutic strategy based on modulation of bombesin growth responses in human lung carcinoma would be well served to take into account the pharmacologic heterogeneity of the relevant receptors.
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Affiliation(s)
- Z Fathi
- Laboratory of Biological Chemistry, National Cancer Institute, Bethesda, Maryland 20892, USA
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Affiliation(s)
- G S Kroog
- Laboratory of Neurochemistry, National Institute on Deafness and Other Communication Disorders, Bethesda, Maryland, USA
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Preston SR, Woodhouse LF, Jones-Blackett S, Miller GV, Primrose JN. High-affinity binding sites for gastrin-releasing peptide on human colorectal cancer tissue but not uninvolved mucosa. Br J Cancer 1995; 71:1087-9. [PMID: 7734305 PMCID: PMC2033785 DOI: 10.1038/bjc.1995.210] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Human colorectal cancer tissue and matched uninvolved mucosa from 21 patients were examined by radioligand displacement for the presence of binding sites for bombesin-like peptides. Five cancers, but no uninvolved mucosa, expressed high-affinity, low-capacity bombesin binding sites (Kd = 6.53 nM, Bmax = 58.6 fmol mg-1 protein) of the gastrin-releasing peptide (GRP)-preferring subtype (IC50 4.8 nM). Bombesin-like peptides may have a role in the pathogenesis of colorectal cancer, and bombesin receptor antagonists may be of value in the treatment of receptor-positive tumours.
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Affiliation(s)
- S R Preston
- Academic Unit of Surgery, St. James's University Hospital, Leeds, UK
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50
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Benya RV, Kusui T, Battey JF, Jensen RT. Chronic desensitization and down-regulation of the gastrin-releasing peptide receptor are mediated by a protein kinase C-dependent mechanism. J Biol Chem 1995; 270:3346-52. [PMID: 7852420 DOI: 10.1074/jbc.270.7.3346] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The cellular basis of down-regulation and desensitization in phospholipase C-linked receptors is unclear. Recent studies with some receptors suggest that elements in the carboxyl terminus of the receptor are important in mediating these processes. Three mutant gastrin-releasing peptide receptors (GRP-R) were studied: one whose last 37 carboxyl-terminal amino acids were eliminated (construct MGT346); one that replaced all of the carboxyl-terminal Ser and Thr eliminated in MGT346 with Ala, Asn, or Gly (construct JF1); and one that selectively replaced the Ser and Thr of the protein kinase C consensus sequence (PKC-CS) located within the same region with alanine (construct TS360AA). Desensitization was assessed by measuring the ability to activate phospholipase C and increase cellular [3H]inositol phosphates, or increase [Ca2+]i, after pre-exposure to 3 nM bombesin for 24 h. Wild-type GRP-R was maximally desensitized and down-regulated after a 24-h exposure to 3 nM bombesin, and removal of the PKC-CS alone markedly attenuated each process. Elimination of additional serines and threonines by truncation (MGT346) or replacement (JF1) did not decrease down-regulation or desensitization further. To confirm the necessity of second messenger activation in mediating down-regulation, we further investigated two additional mutant GRP-R that bound agonist with high affinity but fail to activate phospholipase C (constructs R139G and A263E). Neither construct underwent significant down-regulation. Removal of all GRP-R carboxyl-terminal Ser or Thr, either by MGT346 or JF1, reduced internalization by > 80%, whereas elimination of the PKC-CS in TS360AA only attenuated internalization by 21 +/- 2%. These data suggest that activation of the distal carboxyl-terminal PKC-CS is essential for chronic desensitization and down-regulation of the GRP-R, and provide no evidence for involvement of second messenger-independent processes. In contrast, internalization is equally regulated by both second messenger-dependent and independent processes.
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Affiliation(s)
- R V Benya
- Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-1804
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