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Corlett A, Pinson JA, Rahimi MN, Zuylekom JV, Cullinane C, Blyth B, Thompson PE, Hutton CA, Roselt PD, Haskali MB. Development of Highly Potent Clinical Candidates for Theranostic Applications against Cholecystokinin-2 Receptor Positive Cancers. J Med Chem 2023; 66:10289-10303. [PMID: 37493526 DOI: 10.1021/acs.jmedchem.3c00377] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Peptide receptor radionuclide therapy (PRRT) is a promising form of systemic radiation therapy designed to eradicate cancer. Cholecystokinin-2 receptor (CCK2R) is an important molecular target that is highly expressed in a range of cancers. This study describes the synthesis and in vivo characterization of a novel series of 177Lu-labeled peptides ([177Lu]Lu-2b-4b) in comparison with the reference CCK2R-targeting peptide CP04 ([177Lu]Lu-1b). [177Lu]Lu-1b-4b showed high chemical purity (HPLC ≥ 94%), low Log D7.4 (-4.09 to -4.55) with strong binding affinity to CCK2R (KD 0.097-1.61 nM), and relatively high protein binding (55.6-80.2%) and internalization (40-67%). Biodistribution studies of the novel 177Lu-labeled peptides in tumors (AR42J and A431-CCK2R) showed uptake one- to eight-fold greater than the reference compound CP04 at 1, 24, and 48 h. Rapid clearance and high tumor uptake and retention were established for [177Lu]Lu-2b-4b, making these compounds excellent candidates for theranostic applications against CCK2R-expressing tumors.
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Affiliation(s)
- Alicia Corlett
- Department of Nuclear Medicine, The Royal Melbourne Hospital, Parkville, Victoria, 3000, Australia
| | - Jo-Anne Pinson
- The Radiopharmaceutical Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Marwa N Rahimi
- The Radiopharmaceutical Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Jessica Van Zuylekom
- Models of Cancer Translational Research Centre, The Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
| | - Carleen Cullinane
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
| | - Benjamin Blyth
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- Models of Cancer Translational Research Centre, The Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
| | - Philip E Thompson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University (Parkville Campus), Parkville, Victoria 3052, Australia
| | - Craig A Hutton
- School of Chemistry, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Peter D Roselt
- Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- The Radiopharmaceutical Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
| | - Mohammad B Haskali
- Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- The Radiopharmaceutical Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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2
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Hörmann AA, Klingler M, Rangger C, Mair C, Joosten L, Franssen GM, Laverman P, von Guggenberg E. Effect of N-Terminal Peptide Modifications on In Vitro and In Vivo Properties of 177Lu-Labeled Peptide Analogs Targeting CCK2R. Pharmaceutics 2023; 15:pharmaceutics15030796. [PMID: 36986657 PMCID: PMC10058949 DOI: 10.3390/pharmaceutics15030796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023] Open
Abstract
The therapeutic potential of minigastrin (MG) analogs for the treatment of cholecystokinin-2 receptor (CCK2R)-expressing cancers is limited by poor in vivo stability or unfavorable accumulation in non-target tissues. Increased stability against metabolic degradation was achieved by modifying the C-terminal receptor-specific region. This modification led to significantly improved tumor targeting properties. In this study, further N-terminal peptide modifications were investigated. Two novel MG analogs were designed starting from the amino acid sequence of DOTA-MGS5 (DOTA-DGlu-Ala-Tyr-Gly-Trp-(N-Me)Nle-Asp-1Nal-NH2). Introduction of a penta-DGlu moiety and replacement of the four N-terminal amino acids by a non-charged hydrophilic linker was investigated. Retained receptor binding was confirmed using two CCK2R-expressing cell lines. The effect on metabolic degradation of the new 177Lu-labeled peptides was studied in human serum in vitro, as well as in BALB/c mice in vivo. The tumor targeting properties of the radiolabeled peptides were assessed using BALB/c nude mice bearing receptor-positive and receptor-negative tumor xenografts. Both novel MG analogs were found to have strong receptor binding, enhanced stability, and high tumor uptake. Replacement of the four N-terminal amino acids by a non-charged hydrophilic linker lowered the absorption in the dose-limiting organs, whereas introduction of the penta-DGlu moiety increased uptake in renal tissue.
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Affiliation(s)
- Anton Amadeus Hörmann
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Maximilian Klingler
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Christine Rangger
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Christian Mair
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Lieke Joosten
- Department of Medical Imaging, Nuclear Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Gerben M. Franssen
- Department of Medical Imaging, Nuclear Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Peter Laverman
- Department of Medical Imaging, Nuclear Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Elisabeth von Guggenberg
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria
- Correspondence: ; Tel.: +43-512-504-80960
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Role of PET/Computed Tomography in Elderly Thyroid Cancer: Tumor Biology and Clinical Management. PET Clin 2023; 18:81-101. [PMID: 36718717 DOI: 10.1016/j.cpet.2022.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PET/computed tomography (CT) studies can be potentially useful in elderly thyroid carcinoma patients for exploring the disease biology, especially in metastatic setting and thereby directing appropriate therapeutic management on case-to-case basis, adopting nuclear theranostics, and disease prognostication. With the availability of multiple PET radiopharmaceuticals, it would be worthwhile to evolve and optimally use FDG and the other non-fluorodeoxyglucose and investigational PET/CT tracers as per the clinical situation and need and thereby define their utilities in a given case scenario. In this regard, (I) differentiated thyroid carcinoma (DTC) including radioiodine refractory disease, poorly differentiated thyroid cancer (PDTC) and TENIS, (II) medullary thyroid carcinoma (MTC), (III) anaplastic carcinoma and (IV) Primary thyroid lymphoma (PTL) should be viewed and dealt separately.
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4
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Maina T, Nock BA. Gamma camera imaging by radiolabeled gastrin/cholecystokinin analogs. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00183-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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5
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Velikyan I, Rosenström U, Rosestedt M, Eriksson O, Antoni G. Improved Radiolytic Stability of a 68Ga-labelled Collagelin Analogue for the Imaging of Fibrosis. Pharmaceuticals (Basel) 2021; 14:990. [PMID: 34681214 PMCID: PMC8537947 DOI: 10.3390/ph14100990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/22/2021] [Accepted: 09/22/2021] [Indexed: 11/29/2022] Open
Abstract
There is an unmet medical need for non-invasive, sensitive, and quantitative methods for the assessment of fibrosis. Herein, an improved collagelin analogue labelled with gallium-68 for use with positron emission tomography (PET) is presented. A cyclic peptide, c[CPGRVNleHGLHLGDDEGPC], was synthesized by solid-phase peptide synthesis, conjugated to 2-(4,7-bis(2-(tert-butoxy)-2-oxoethyl)-1,4,7-triazonan-1-yl)acetic acid, and labelled with gallium-68. High performance liquid chromatography (HPLC) was used for the quality and stability assessment of the collagelin analogue. Non-specific organ distribution, blood clearance, and excretion rates were investigated in healthy mice and rats using ex vivo organ distribution analysis and dynamic in vivo PET/CT. Mice with carbon tetrachloride (CCl4) induced liver fibrosis were used for the investigation of specific binding via in vitro frozen section autoradiography, ex vivo organ distribution, and in vivo PET/CT. A non-decay corrected radiochemical yield (48 ± 6%) of [68Ga]Ga-NOTA-PEG2-c[CPGRVNleHGLHLGDDEGPC] ([68Ga]Ga-NO2A-[Nle13]-Col) with a radiochemical purity of 98 ± 2% was achieved without radical scavengers. The 68Ga-labelling was regioselective and stable at ambient temperature for at least 3 h. The autoradiography of the cryosections of fibrotic mouse liver tissue demonstrated a distinct heterogeneous radioactivity uptake that correlated with the fibrosis scores estimated after Sirius Red staining. The blood clearance and tissue washout from the [68Ga]Ga-NO2A-[Nle13]-Col was fast in both normal and diseased mice. Dosimetry investigation in rats indicated the possibility for 4-5 PET/CT examinations per year. Radiolytic stability of the collagelin analogue was achieved by the substitution of methionine with norleucine amino acid residue without a deterioration of its binding capability. [68Ga]Ga-NO2A-[Nle13]-Col demonstrated a safe dosimetry profile suitable for repeated scanning.
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Affiliation(s)
- Irina Velikyan
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden; (M.R.); (O.E.)
- PET-Centre, Centre for Medical Imaging, Uppsala University Hospital, SE-75185 Uppsala, Sweden
| | - Ulrika Rosenström
- Department of Medicinal Chemistry, Uppsala University, SE-75123 Uppsala, Sweden;
| | - Maria Rosestedt
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden; (M.R.); (O.E.)
| | - Olof Eriksson
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden; (M.R.); (O.E.)
| | - Gunnar Antoni
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden; (M.R.); (O.E.)
- PET-Centre, Centre for Medical Imaging, Uppsala University Hospital, SE-75185 Uppsala, Sweden
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Askari Rizvi SF, Zhang H. Emerging trends of receptor-mediated tumor targeting peptides: A review with perspective from molecular imaging modalities. Eur J Med Chem 2021; 221:113538. [PMID: 34022717 DOI: 10.1016/j.ejmech.2021.113538] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 01/10/2023]
Abstract
Natural peptides extracted from natural components such are known to have a relatively short in-vivo half-life and can readily metabolize by endo- and exo-peptidases. Fortunately, synthetic peptides can be easily manipulated to increase in-vivo stability, membrane permeability and target specificity with some well-known natural families. Many natural as well as synthetic peptides target to their endogenous receptors for diagnosis and therapeutic applications. In order to detect these peptides externally, they must be modified with radionuclides compatible with single photon emission computed tomography (SPECT) or positron emission tomography (PET). Although, these techniques mainly rely on physiological changes and have profound diagnostic strength over anatomical modalities such as MRI and CT. However, both SPECT and PET observed to possess lack of anatomical reference frame which is a key weakness of these techniques, and unfortunately, cannot be available freely in most clinical centres especially in under-developing countries. Hence, it is need of the time to design and develop economic, patient friendly and versatile strategies to grapple with existing problems without any hazardous side effects. Optical molecular imaging (OMI) has emerged as a novel technique in field of medical science using fluorescent probes as imaging modality and has ability to couple with organic drugs, small molecules, chemotherapeutics, DNA, RNA, anticancer peptide and protein without adding chelators as necessary for radionuclides. Furthermore, this review focuses on difference in imaging modalities and provides ample knowledge about reliable, economic and patient friendly optical imaging technique rather radionuclide-based imaging techniques.
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Affiliation(s)
- Syed Faheem Askari Rizvi
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 730000, Gansu, PR China
| | - Haixia Zhang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 730000, Gansu, PR China.
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7
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Structural modifications of amino acid sequences of radiolabeled peptides for targeted tumor imaging. Bioorg Chem 2020; 99:103802. [DOI: 10.1016/j.bioorg.2020.103802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/19/2020] [Accepted: 03/25/2020] [Indexed: 12/18/2022]
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Klingler M, Hörmann AA, Guggenberg EV. Cholecystokinin-2 Receptor Targeting with Radiolabeled Peptides: Current Status and Future Directions. Curr Med Chem 2020; 27:7112-7132. [PMID: 32586246 PMCID: PMC7116483 DOI: 10.2174/0929867327666200625143035] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 05/01/2020] [Accepted: 05/13/2020] [Indexed: 02/08/2023]
Abstract
A wide variety of radiolabeled peptide analogs for specific targeting of cholecystokinin- 2 receptors (CCK2R) has been developed in the last decades. Peptide probes based on the natural ligands Minigastrin (MG) and Cholecystokinin (CCK) have a high potential for molecular imaging and targeted radiotherapy of different human tumors, such as Medullary Thyroid Carcinoma (MTC) and Small Cell Lung Cancer (SCLC). MG analogs with high persistent uptake in CCK2R expressing tumors have been preferably used for the development of radiolabeled peptide analogs. The clinical translation of CCK2R targeting has been prevented due to high kidney uptake or low metabolic stability of the different radiopeptides developed. Great efforts in radiopharmaceutical development have been undertaken to overcome these limitations. Various modifications in the linear peptide sequence of MG have been introduced mainly with the aim to reduce kidney retention. Furthermore, improved tumor uptake could be obtained by in situ stabilization of the radiopeptide against enzymatic degradation through coinjection of peptidase inhibitors. Recent developments focusing on the stabilization of the Cterminal receptor binding sequence (Trp-Met-Asp-Phe-NH2) have led to new radiolabeled MG analogs with highly improved tumor uptake and tumor-to-kidney ratio. In this review, all the different aspects in the radiopharmaceutical development of CCK2R targeting peptide probes are covered, giving also an overview on the clinical investigations performed so far. The recent development of radiolabeled MG analogs, which are highly stabilized against enzymatic degradation in vivo, promises to have a high impact on the clinical management of patients with CCK2R expressing tumors in the near future.
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Affiliation(s)
- Maximilian Klingler
- Department of Nuclear Medicine, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Anton Amadeus Hörmann
- Department of Nuclear Medicine, Medical University of Innsbruck, A-6020 Innsbruck, Austria
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Abstract
Medullary thyroid carcinoma (MTC), arising from the parafollicular C cells of the thyroid, accounts for 1–2% of thyroid cancers. MTC is frequently aggressive and metastasizes to cervical and mediastinal lymph nodes, lungs, liver, and bones. Although a number of new imaging modalities for directing the management of oncologic patients evolved over the last two decades, the clinical application of these novel techniques is limited in MTC. In this article, we review the biology and molecular aspects of MTC as an important background for the use of current imaging modalities and approaches for this tumor. We discuss the modern and currently available imaging techniques—advanced magnetic resonance imaging (MRI)-based techniques such as whole-body MRI, dynamic contrast-enhanced (DCE) technique, diffusion-weighted imaging (DWI), positron emission tomography/computed tomography (PET/CT) with 18F-FDOPA and 18F-FDG, and integrated positron emission tomography/magnetic resonance (PET/MR) hybrid imaging—for primary as well as metastatic MTC tumor, including its metastatic spread to lymph nodes and the most common sites of distant metastases: lungs, liver, and bones.
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Klingler M, Summer D, Rangger C, Haubner R, Foster J, Sosabowski J, Decristoforo C, Virgolini I, von Guggenberg E. DOTA-MGS5, a New Cholecystokinin-2 Receptor-Targeting Peptide Analog with an Optimized Targeting Profile for Theranostic Use. J Nucl Med 2018; 60:1010-1016. [PMID: 30530828 DOI: 10.2967/jnumed.118.221283] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/13/2018] [Indexed: 12/25/2022] Open
Abstract
Molecular imaging and targeted radiotherapy with radiolabeled cholecystokinin-2 receptor (CCK2R) targeting peptide probes holds high promise to improve the clinical management of patients with metastatic medullary thyroid carcinoma and other CCK2R-expressing malignancies. Low stability and suboptimal targeting of currently available radiolabeled peptide analogs has prompted us to seek new stabilization strategies. In this study, we present a new minigastrin analog with site-specific C-terminal modifications showing a highly optimized targeting profile. Methods: DOTA-D-Glu-Ala-Tyr-Gly-Trp-(N-Me)Nle-Asp-1-Nal-NH2 (DOTA-MGS5) radiolabeled with 111In, 68Ga, and 177Lu was evaluated in extensive in vitro stability studies. For 177Lu-DOTA-MGS5, additional metabolic studies were performed on BALB/c mice. Receptor affinity and cell uptake were studied in A431 human epidermoid carcinoma cells transfected with human CCK2R (A431-CCK2R), as well as the same cell line transfected with the empty vector (A431-mock). A431-CCK2R/A431-mock xenografted athymic BALB/c nude mice were used for biodistribution studies and small-animal SPECT/CT. Results: DOTA-MGS5 radiolabeled with 111In and 177Lu showed a highly increased stability against enzymatic degradation in different media up to 24 h of incubation. Similar results were observed for 68Ga-DOTA-MGS5 incubated up to 4 h. In the blood of mice injected with 177Lu-DOTA-MGS5, at least 70% intact radiopeptide was detected up to 1 h after injection. The unlabeled peptide and the complexes with the natural isotopes showed retained receptor affinity, and the radiopeptides showed unexpectedly high cell uptake in A431-CCK2R cells (>60% at 4 h). Regardless of the radiometal used for labeling, impressively high uptake in A431-CCK2R xenografts was found (∼20% injected activity/g 1-4 h after injection), whereas the uptake in A431-mock xenografts was negligible. Low background activity and favorable tumor-to-kidney ratios (4-6) allowed for high image contrast in small-animal SPECT/CT. Conclusion: The excellent targeting properties of DOTA-MGS5 support future clinical studies evaluating the diagnostic and therapeutic potential in patients with progressive or metastatic medullary thyroid carcinoma, as well as other advanced-stage CCK2R-expressing malignancies.
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Affiliation(s)
- Maximilian Klingler
- Department of Nuclear Medicine, Medical University of Innsbruck, Innsbruck, Austria; and
| | - Dominik Summer
- Department of Nuclear Medicine, Medical University of Innsbruck, Innsbruck, Austria; and
| | - Christine Rangger
- Department of Nuclear Medicine, Medical University of Innsbruck, Innsbruck, Austria; and
| | - Roland Haubner
- Department of Nuclear Medicine, Medical University of Innsbruck, Innsbruck, Austria; and
| | - Julie Foster
- Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Jane Sosabowski
- Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Clemens Decristoforo
- Department of Nuclear Medicine, Medical University of Innsbruck, Innsbruck, Austria; and
| | - Irene Virgolini
- Department of Nuclear Medicine, Medical University of Innsbruck, Innsbruck, Austria; and
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Erba PA, Maecke H, Mikolajczak R, Decristoforo C, Zaletel K, Maina-Nock T, Peitl PK, Garnuszek P, Froberg A, Goebel G, de Jong M, Jabrocka-Hybel A, Konijnenberg M, Virgolini I, Nock B, Lenda-Tracz W, Pawlak D, Rangger C, Trofimiuk-Müldner M, Sowa-Staszczak A, Tomaszuk M, von Guggenberg E, Scarpa L, Hubalewska-Dydejczyk A. A novel CCK2/gastrin receptor-localizing radiolabeled peptide probe for personalized diagnosis and therapy of patients with progressive or metastatic medullary thyroid carcinoma: a multicenter phase I GRAN-T-MTC study. Pol Arch Intern Med 2018; 128:791-795. [PMID: 30516761 PMCID: PMC6347971 DOI: 10.20452/pamw.4387] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Klingler M, Decristoforo C, Rangger C, Summer D, Foster J, Sosabowski JK, von Guggenberg E. Site-specific stabilization of minigastrin analogs against enzymatic degradation for enhanced cholecystokinin-2 receptor targeting. Am J Cancer Res 2018; 8:2896-2908. [PMID: 29896292 PMCID: PMC5996369 DOI: 10.7150/thno.24378] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/01/2018] [Indexed: 12/12/2022] Open
Abstract
Minigastrin (MG) analogs show high affinity to the cholecystokinin-2 receptor (CCK2R) and have therefore been intensively studied to find a suitable analog for imaging and treatment of CCK2R-expressing tumors. The clinical translation of the radioligands developed thus far has been hampered by high kidney uptake or low enzymatic stability. In this study, we aimed to develop new MG analogs with improved targeting properties stabilized against degradation through site-specific amino acid modifications. Method: Based on the lead structure of a truncated MG analog, four new MG derivatives with substitutions in the C-terminal part of the peptide (Trp-Met-Asp-Phe-NH2) were synthesized and derivatized with DOTA at the N-terminus for radiolabeling with trivalent radiometals. The in vitro properties of the new analogs were characterized by analyzing the lipophilicity, the protein binding, and the stability of the Indium-111 (111In)-labeled analogs in different media. Two different cell lines, AR42J cells physiologically expressing the rat CCK2R and A431 cells transfected with human CCK2R (A431-CCK2R), were used to study the receptor affinity and cell uptake. For the two most promising MG analogs, metabolic studies in normal BALB/c mice were carried out as well as biodistribution and imaging studies in tumor xenografted athymic BALB/c nude mice. Results: Two out of four synthesized peptide analogs (DOTA-MGS1 and DOTA-MGS4) showed retained receptor affinity and cell uptake when radiolabeled with 111In. These two peptide analogs, however, showed a different stability against enzymatic degradation in vitro and in vivo. When injected to normal BALB/c mice, for 111In-DOTA-MGS1 at 10 min post injection (p.i.) no intact radiopeptide was found in the blood, whereas for 111In-DOTA-MGS4 more than 75% was still intact. 111In-DOTA-MGS4 showed a clear increase in injected activity per gram tissue (IA/g) for A431-CCK2R xenografts (10.40±2.21% IA/g 4 h p.i.) when compared to 111In-DOTA-MGS1 (1.23±0.15% IA/g 4 h p.i.). The tumor uptake of 111In-DOTA-MGS4 was also combined with a low uptake in stomach and kidney leading to high-contrast NanoSPECT/CT images. Conclusion: Of the four new MG analogs developed, the best results in terms of enzymatic stability and increased tumor targeting were obtained with 111In-DOTA-MGS4 showing two substitutions with N-methylated amino acids. 111In-DOTA-MGS4 was also superior to other MG analogs reported thus far and seems therefore an extremely promising targeting molecule for theranostic use with alternative radiometals.
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Rangger C, Klingler M, Balogh L, Pöstényi Z, Polyak A, Pawlak D, Mikołajczak R, von Guggenberg E. 177Lu Labeled Cyclic Minigastrin Analogues with Therapeutic Activity in CCK2R Expressing Tumors: Preclinical Evaluation of a Kit Formulation. Mol Pharm 2017; 14:3045-3058. [PMID: 28728415 DOI: 10.1021/acs.molpharmaceut.7b00241] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Minigastrin (MG) analogues specifically target cholecystokinin-2 receptors (CCK2R) expressed in different tumors and enable targeted radiotherapy of advanced and disseminated disease when radiolabeled with a beta emitter such as 177Lu. Especially truncated MG analogues missing the penta-Glu sequence are associated with low kidney retention and seem therefore most promising for therapeutic use. Based on [d-Glu1,desGlu2-6]MG (MG11) we have designed the two cyclic MG analogues cyclo1,9[γ-d-Glu1,desGlu2-6,d-Lys9]MG (cyclo-MG1) and cyclo1,9[γ-d-Glu1,desGlu2-6,d-Lys9,Nle11]MG (cyclo-MG2). In the present work we have developed and preclinically evaluated a pharmaceutical kit formulation for the labeling with 177Lu of the two DOTA-conjugated cyclic MG analogues. The stability of the kits during storage as well as the stability of the radiolabeled peptides was investigated. A cell line stably transfected with human CCK2R and a control cell line without receptor expression were used for in vitro and in vivo studies with the radioligands prepared from kit formulations. In terms of stability 177Lu-DOTA-cyclo-MG2 showed advantages over 177Lu-DOTA-cyclo-MG1. Still, for both radioligands a high receptor-mediated cell uptake and favorable pharmacokinetic profile combining receptor-specific tumor uptake with low unspecific tissue uptake and low kidney retention were confirmed. Investigating the therapy efficacy and treatment toxicity in xenografted BALB/c nude mice a receptor-specific and comparable therapeutic effect could be demonstrated for both radioligands. A 1.7- to 2.6-fold increase in tumor volume doubling time was observed for receptor-positive tumors in treated versus untreated animals, which was 39-73% higher when compared to receptor-negative tumors. The treatment was connected with transient bone marrow toxicity and minor signs of kidney toxicity. All together the obtained results support further studies for the clinical translation of this new therapeutic approach.
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Affiliation(s)
- Christine Rangger
- Department of Nuclear Medicine, Medical University of Innsbruck , 6020 Innsbruck, Austria
| | - Maximilian Klingler
- Department of Nuclear Medicine, Medical University of Innsbruck , 6020 Innsbruck, Austria
| | - Lajos Balogh
- Department of Nuclear Medicine and Translational Biological Sciences, OKK-OSSKI , 1221 Budapest, Hungary
| | - Zita Pöstényi
- Department of Nuclear Medicine and Translational Biological Sciences, OKK-OSSKI , 1221 Budapest, Hungary
| | - Andras Polyak
- Department of Nuclear Medicine and Translational Biological Sciences, OKK-OSSKI , 1221 Budapest, Hungary
| | - Dariusz Pawlak
- Radioisotope Centre POLATOM, National Centre for Nuclear Research , 05-400 Otwock, Poland
| | - Renata Mikołajczak
- Radioisotope Centre POLATOM, National Centre for Nuclear Research , 05-400 Otwock, Poland
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Laval M, Marshall KM, Sachinidis J, Scott A, Eutick M, Baldwin GS. Complexes of gastrin with In 3+, Ru 3+ or Ga 3+ ions are not recognised by the cholecystokinin 2 receptor. J Biol Inorg Chem 2017; 22:999-1006. [PMID: 28702751 DOI: 10.1007/s00775-017-1478-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/21/2017] [Indexed: 11/29/2022]
Abstract
The peptide hormone gastrin (Gamide) binds trivalent metal ions, including indium (In), ruthenium (Ru) and gallium (Ga), with high affinity. Complexes of gastrin with chelated isotopes of In and Ga have previously been used for the location of tumours expressing the cholecystokinin 2 receptor (CCK2R). The aim of the present study was to purify the complexes of Gamide with radioactive isotopes of In, Ru or Ga and to investigate their ability to bind to the CCK2R. The radioactive Gamide complexes were purified on Sep-Pak C18 cartridges or by anion exchange HPLC. Binding to the CCK2R was assessed with a stably transfected clone of the gastric carcinoma cell line AGS. The 106Ru-Gamide complex could be eluted from the C18 cartridge; the 111In-Gamide and 68Ga-Gamide complexes bound irreversibly. All three complexes were successfully purified by anion exchange HPLC. The failure to detect binding of the 111In-Gamide, 106Ru-Gamide and 68Ga-Gamide complexes to the CCK2R suggests that formation of these complexes will not be useful for the detection of tumours expressing this receptor, but may instead provide alternative ways to block the actions of Gamide as a growth factor or a stimulant of gastric acid secretion. The complexes between the hormone gastrin and radioactive 111In, 106Ru or 68Ga ions were purified by anion exchange HPLC using a NaCl gradient. The failure to detect binding of the complexes to the cholecystokinin 2 receptor suggests that metal ion treatment may provide novel approaches to block the biological actions of gastrin.
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Affiliation(s)
- Marie Laval
- Department of Surgery, Austin Health, University of Melbourne, Level 8, Lance Townsend Building, Studley Road, Melbourne, VIC, 3084, Australia.
| | - Kathryn M Marshall
- Department of Surgery, Austin Health, University of Melbourne, Level 8, Lance Townsend Building, Studley Road, Melbourne, VIC, 3084, Australia
| | - John Sachinidis
- Department of Molecular Imaging and Therapy, Austin Health, Melbourne, VIC, Australia
| | - Andrew Scott
- Department of Molecular Imaging and Therapy, Austin Health, Melbourne, VIC, Australia
- Olivia Newton-John Cancer Research Institute, La Trobe University, Melbourne, VIC, Australia
- Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Mal Eutick
- Phebra Pty. Ltd, Hunters Hill, NSW, Australia
| | - Graham S Baldwin
- Department of Surgery, Austin Health, University of Melbourne, Level 8, Lance Townsend Building, Studley Road, Melbourne, VIC, 3084, Australia
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Charron CL, Hickey JL, Nsiama TK, Cruickshank DR, Turnbull WL, Luyt LG. Molecular imaging probes derived from natural peptides. Nat Prod Rep 2017; 33:761-800. [PMID: 26911790 DOI: 10.1039/c5np00083a] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Covering: up to the end of 2015.Peptides are naturally occurring compounds that play an important role in all living systems and are responsible for a range of essential functions. Peptide receptors have been implicated in disease states such as oncology, metabolic disorders and cardiovascular disease. Therefore, natural peptides have been exploited as diagnostic and therapeutic agents due to the unique target specificity for their endogenous receptors. This review discusses a variety of natural peptides highlighting their discovery, endogenous receptors, as well as their derivatization to create molecular imaging agents, with an emphasis on the design of radiolabelled peptides. This review also highlights methods for discovering new and novel peptides when knowledge of specific targets and endogenous ligands are not available.
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Affiliation(s)
- C L Charron
- Department of Chemistry, The University of Western Ontario, London, Canada.
| | - J L Hickey
- Department of Chemistry, The University of Western Ontario, London, Canada.
| | - T K Nsiama
- London Regional Cancer Program, Lawson Health Research Institute, London, Canada
| | - D R Cruickshank
- Department of Chemistry, The University of Western Ontario, London, Canada.
| | - W L Turnbull
- Department of Chemistry, The University of Western Ontario, London, Canada.
| | - L G Luyt
- Department of Chemistry, The University of Western Ontario, London, Canada. and Departments of Oncology and Medical Imaging, The University of Western Ontario, London, Canada and London Regional Cancer Program, Lawson Health Research Institute, London, Canada
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Fani M, Peitl PK, Velikyan I. Current Status of Radiopharmaceuticals for the Theranostics of Neuroendocrine Neoplasms. Pharmaceuticals (Basel) 2017; 10:E30. [PMID: 28295000 PMCID: PMC5374434 DOI: 10.3390/ph10010030] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 02/06/2023] Open
Abstract
Nuclear medicine plays a pivotal role in the management of patients affected by neuroendocrine neoplasms (NENs). Radiolabeled somatostatin receptor analogs are by far the most advanced radiopharmaceuticals for diagnosis and therapy (radiotheranostics) of NENs. Their clinical success emerged receptor-targeted radiolabeled peptides as an important class of radiopharmaceuticals and it paved the way for the investigation of other radioligand-receptor systems. Besides the somatostatin receptors (sstr), other receptors have also been linked to NENs and quite a number of potential radiolabeled peptides have been derived from them. The Glucagon-Like Peptide-1 Receptor (GLP-1R) is highly expressed in benign insulinomas, the Cholecystokinin 2 (CCK2)/Gastrin receptor is expressed in different NENs, in particular medullary thyroid cancer, and the Glucose-dependent Insulinotropic Polypeptide (GIP) receptor was found to be expressed in gastrointestinal and bronchial NENs, where interestingly, it is present in most of the sstr-negative and GLP-1R-negative NENs. Also in the field of sstr targeting new discoveries brought into light an alternative approach with the use of radiolabeled somatostatin receptor antagonists, instead of the clinically used agonists. The purpose of this review is to present the current status and the most innovative strategies for the diagnosis and treatment (theranostics) of neuroendocrine neoplasms using a cadre of radiolabeled regulatory peptides targeting their receptors.
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Affiliation(s)
- Melpomeni Fani
- Division of Radiopharmaceutical Chemistry, University Hospital of Basel, 4031 Basel, Switzerland.
| | - Petra Kolenc Peitl
- Department of Nuclear Medicine, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia.
| | - Irina Velikyan
- Department of Medicinal Chemistry, Uppsala University, 751 23 Uppsala, Sweden.
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Kaloudi A, Nock BA, Lymperis E, Krenning EP, de Jong M, Maina T. Improving the In Vivo Profile of Minigastrin Radiotracers: A Comparative Study Involving the Neutral Endopeptidase Inhibitor Phosphoramidon. Cancer Biother Radiopharm 2016; 31:20-8. [PMID: 26844849 DOI: 10.1089/cbr.2015.1935] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Minigastrin radiotracers, such as [(111)In-DOTA]MG0 ([(111)In-DOTA-DGlu(1)]minigastrin), have been considered for diagnostic imaging and radionuclide therapy of CCK2R-positive human tumors, such as medullary thyroid carcinoma. However, the high kidney retention assigned to the pentaGlu(2-6) repeat in the peptide sequence has compromised their clinical applicability. On the other hand, truncated des(Glu)(2-6)-analogs, such as [(111)In-DOTA]MG11 ([(111)In-DOTA-DGlu(10),desGlu(2-6)]minigastrin), despite their low renal uptake, show poor bioavailability and tumor targeting. [(111)In]CP04 ([(111)In-DOTA-DGlu(1-6)]minigastrin) acquired by Glu(2-6)/DGlu(2-6) substitution showed promising tumor-to-kidney ratios in rodents. In the present study, we compare the biological profiles of [(111)In]CP04, [(111)In-DOTA]MG11, and [(111)In-DOTA]MG0 during in situ neutral endopeptidase (NEP) inhibition, recently shown to improve the bioavailability of several peptide radiotracers. After coinjection of the NEP inhibitor, phosphoramidon (PA), the stability of [(111)In]CP04 and [(111)In-DOTA]MG0 in peripheral mouse blood increased, with an exceptional >14-fold improvement monitored for [(111)In-DOTA]MG11. In line with these findings, PA treatment increased the uptake of [(111)In]CP04 (8.5 ± 0.4%ID/g to 16.0 ± 2.3%ID/g) and [(111)In-DOTA]MG0 (11.9 ± 2.2%ID/g to 17.2 ± 0.9%ID/g) in A431-CCK2R(+) tumors at 4 hours postinjection, whereas the respective increase for [(111)In-DOTA]MG11 was >6-fold (2.5 ± 0.9%ID/g to 15.1 ± 1.7%ID/g). Interestingly, kidney uptake remained lowest for [(111)In-DOTA]MG11, but unfavorably increased by PA treatment for [(111)In-DOTA]MG0. Thus, overall, the most favorable in vivo profile was displayed by [(111)In-DOTA]MG11 during NEP inhibition, highlighting the need to validate this promising concept in the clinic.
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Affiliation(s)
- Aikaterini Kaloudi
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Berthold A Nock
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Emmanouil Lymperis
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Eric P Krenning
- 2 Department of Nuclear Medicine, Erasmus MC , Rotterdam, The Netherlands
| | - Marion de Jong
- 2 Department of Nuclear Medicine, Erasmus MC , Rotterdam, The Netherlands .,3 Department of Radiology, Erasmus MC , Rotterdam, The Netherlands
| | - Theodosia Maina
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
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Maina T, Konijnenberg MW, KolencPeitl P, Garnuszek P, Nock BA, Kaloudi A, Kroselj M, Zaletel K, Maecke H, Mansi R, Erba P, von Guggenberg E, Hubalewska-Dydejczyk A, Mikolajczak R, Decristoforo C. Preclinical pharmacokinetics, biodistribution, radiation dosimetry and toxicity studies required for regulatory approval of a phase I clinical trial with (111)In-CP04 in medullary thyroid carcinoma patients. Eur J Pharm Sci 2016; 91:236-42. [PMID: 27185299 PMCID: PMC4948680 DOI: 10.1016/j.ejps.2016.05.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 05/03/2016] [Accepted: 05/12/2016] [Indexed: 01/23/2023]
Abstract
Introduction From a series of radiolabelled cholecystokinin (CCK) and gastrin analogues, 111In-CP04 (111In-DOTA-(DGlu)6-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2) was selected for further translation as a diagnostic radiopharmaceutical towards a first-in-man study in patients with medullary thyroid carcinoma (MTC). A freeze-dried kit formulation for multicentre application has been developed. We herein report on biosafety, in vivo stability, biodistribution and dosimetry aspects of 111In-CP04 in animal models, essential for the regulatory approval of the clinical trial. Materials and methods Acute and extended single dose toxicity of CP04 was tested in rodents, while the in vivo stability of 111In-CP04 was assessed by HPLC analysis of mouse blood samples. The biodistribution of 111In-CP04 prepared from a freeze-dried kit was studied in SCID mice bearing double A431-CCK2R(±) xenografts at 1, 4 and 24 h pi. Further 4-h animal groups were either additionally treated with the plasma expander gelofusine or injected with 111In-CP04 prepared by wet-labelling. Pharmacokinetics in healthy mice included the 30 min, 1, 4, 24, 48 and 72 h time points pi. Dosimetric calculations were based on extrapolation of mice data to humans adopting two scaling models. Results CP04 was well-tolerated by both mice and rats, with an LD50 > 178.5 μg/kg body weight for mice and a NOAEL (no-observed-adverse-effect-level) of 89 μg/kg body weight for rats. After labelling, 111In-CP04 remained >70% intact in peripheral mouse blood at 5 min pi. The uptake of 111In-CP04 prepared from the freeze-dried kit and by wet-labelling were comparable in the A431-CCK2R(+)-xenografts (9.24 ± 1.35%ID/g and 8.49 ± 0.39%ID/g, respectively; P > 0.05). Gelofusine-treated mice exhibited significantly reduced kidneys values (1.69 ± 0.15%ID/g vs. 5.55 ± 0.94%ID/g in controls, P < 0.001). Dosimetry data revealed very comparable effective tumour doses for the two scaling models applied, of 0.045 and 0.044 mSv/MBq. Conclusion The present study has provided convincing toxicology, biodistribution and dosimetry data for prompt implementation of the freeze-dried kit formulation without or with gelofusine administration in a multicentre clinical trial in MTC patients.
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Affiliation(s)
- Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Athens, Greece
| | - Mark W Konijnenberg
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Petra KolencPeitl
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia
| | - Piotr Garnuszek
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, Otwock, Poland
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Athens, Greece
| | | | - Marko Kroselj
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia
| | - Katja Zaletel
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia
| | - Helmut Maecke
- Department of Nuclear Medicine, University Hospital Freiburg, Germany
| | - Rosalba Mansi
- Department of Nuclear Medicine, University Hospital Freiburg, Germany
| | - Paola Erba
- Department of Nuclear Medicine, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy
| | | | | | - Renata Mikolajczak
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, Otwock, Poland
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Baldwin GS, George GN, Pushie MJ. High Affinity Binding of Indium and Ruthenium Ions by Gastrins. PLoS One 2015; 10:e0140126. [PMID: 26457677 PMCID: PMC4601796 DOI: 10.1371/journal.pone.0140126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/21/2015] [Indexed: 11/22/2022] Open
Abstract
The peptide hormone gastrin binds two ferric ions with high affinity, and iron binding is essential for the biological activity of non-amidated forms of the hormone. Since gastrins act as growth factors in gastrointestinal cancers, and as peptides labelled with Ga and In isotopes are increasingly used for cancer diagnosis, the ability of gastrins to bind other metal ions was investigated systematically by absorption spectroscopy. The coordination structures of the complexes were characterized by extended X-ray absorption fine structure (EXAFS) spectroscopy. Changes in the absorption of gastrin in the presence of increasing concentrations of Ga3+ were fitted by a 2 site model with dissociation constants (Kd) of 3.3 x 10−7 and 1.1 x 10−6 M. Although the absorption of gastrin did not change upon the addition of In3+ ions, the changes in absorbance on Fe3+ ion binding in the presence of indium ions were fitted by a 2 site model with Kd values for In3+ of 6.5 x 10−15 and 1.7 x 10−7 M. Similar results were obtained with Ru3+ ions, although the Kd values for Ru3+ of 2.6 x 10−13 and 1.2 x 10−5 M were slightly larger than observed for In3+. The structures determined by EXAFS all had metal:gastrin stoichiometries of 2:1 but, while the metal ions in the Fe, Ga and In complexes were bridged by a carboxylate and an oxygen with a metal-metal separation of 3.0–3.3 Å, the Ru complex clearly demonstrated a short range Ru—Ru separation, which was significantly shorter, at 2.4 Å, indicative of a metal-metal bond. We conclude that gastrin selectively binds two In3+ or Ru3+ ions, and that the affinity of the first site for In3+ or Ru3+ ions is higher than for ferric ions. Some of the metal ion-gastrin complexes may be useful for cancer diagnosis and therapy.
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Affiliation(s)
- Graham S. Baldwin
- The University of Melbourne Department of Surgery, Austin Health, Heidelberg, Victoria 3084, Australia
- * E-mail:
| | - Graham N. George
- Molecular and Environmental Science Research Group Department of Geological Sciences, 114 Science Place, University of Saskatchewan, Saskatoon, S7N 5E2, Canada
| | - M. Jake Pushie
- Molecular and Environmental Science Research Group Department of Geological Sciences, 114 Science Place, University of Saskatchewan, Saskatoon, S7N 5E2, Canada
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Kaloudi A, Nock BA, Lymperis E, Sallegger W, Krenning EP, de Jong M, Maina T. In vivo inhibition of neutral endopeptidase enhances the diagnostic potential of truncated gastrin (111)In-radioligands. Nucl Med Biol 2015; 42:824-32. [PMID: 26300210 DOI: 10.1016/j.nucmedbio.2015.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 07/19/2015] [Accepted: 07/24/2015] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Radiolabeled gastrin analogs represent attractive candidates for diagnosis and therapy of cholecystokinin subtype-2 receptor (CCK2R)-expressing tumors. Radiolabeled des(Glu)5-gastrins show favorably low renal accumulation, but localize poorly in CCK2R-positive lesions. We introduce herein three truncated [DOTA-DGlu(10)]gastrin(10-17) analogs, with oxidation-susceptible Met(15) replaced by: (1), (2), or (3), and study the profile of [(111)In]1/2/3 during in vivo inhibition of neutral endopeptidase (NEP) in comparison to the non-truncated [ ([(111)In]4) reference. METHODS Blood samples collected from mice 5 min postinjection (pi) of [(111)In]1/2/3/4 without or with phosphoramidon (PA) coinjection were analyzed by RP-HPLC. Biodistribution was conducted in SCID mice bearing A431-CCK2R(+) or AR42J xenografts 4h after administration of [(111)In]1/2/3/4 without or with PA coinjection. RESULTS Firstly, we observed remarkable increases in the amount of radiopeptides detected intact in the blood of PA-treated mice at 5 min pi compared to controls. Secondly, we noted impressive enhancement of [(111)In]1/2/3 localization in AR42J and A431-CCK2R(+) tumors in mice after PA coinjection. Specifically, the uptake of [(111)In]1 at 4h pi increased from 2.6 ± 0.3%ID/g to 13.3 ± 3.5%ID/g in the AR42J tumors and from 4.3 ± 0.6%ID/g to 20.4 ± 3.6%ID/g in the A431-CCK2R(+) xenografts, with comparable improvements noted for [(111)In]2 and [(111)In]3 as well. Thirdly, renal uptake remained favorably low and unaffected by PA (<2.5%ID/g). Conversely, although the stability and tumor targeting of [(111)In]4 improved, its high renal uptake (>85%ID/g) increased even further by PA (>140%ID/g). CONCLUSIONS In situ inhibition of NEP represents a promising new tool to enhance the diagnostic efficacy of biodegradable gastrin radioligands in the visualization of CCK2R-positive lesions in man.
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Affiliation(s)
- Aikaterini Kaloudi
- Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos", GR-153 10, Athens, Greece
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos", GR-153 10, Athens, Greece
| | - Emmanouil Lymperis
- Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos", GR-153 10, Athens, Greece
| | | | - Eric P Krenning
- Department of Nuclear Medicine, Erasmus MC, 3015 CE, Rotterdam, The Netherlands
| | - Marion de Jong
- Department of Nuclear Medicine, Erasmus MC, 3015 CE, Rotterdam, The Netherlands; Department of Radiology, Erasmus MC, 3015 CE, Rotterdam, The Netherlands
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos", GR-153 10, Athens, Greece.
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Velikyan I. Prospective of ⁶⁸Ga-radiopharmaceutical development. Theranostics 2013; 4:47-80. [PMID: 24396515 PMCID: PMC3881227 DOI: 10.7150/thno.7447] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 10/01/2013] [Indexed: 01/29/2023] Open
Abstract
Positron Emission Tomography (PET) experienced accelerated development and has become an established method for medical research and clinical routine diagnostics on patient individualized basis. Development and availability of new radiopharmaceuticals specific for particular diseases is one of the driving forces of the expansion of clinical PET. The future development of the ⁶⁸Ga-radiopharmaceuticals must be put in the context of several aspects such as role of PET in nuclear medicine, unmet medical needs, identification of new biomarkers, targets and corresponding ligands, production and availability of ⁶⁸Ga, automation of the radiopharmaceutical production, progress of positron emission tomography technologies and image analysis methodologies for improved quantitation accuracy, PET radiopharmaceutical regulations as well as advances in radiopharmaceutical chemistry. The review presents the prospects of the ⁶⁸Ga-based radiopharmaceutical development on the basis of the current status of these aspects as well as wide range and variety of imaging agents.
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Affiliation(s)
- Irina Velikyan
- 1. Preclinical PET Platform, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden
- 2. PET-Centre, Centre for Medical Imaging, Uppsala University Hospital, SE-75185, Uppsala, Sweden
- 3. Department of Radiology, Oncology, and Radiation Science, Uppsala University, SE-75285 Uppsala, Sweden
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Melicharova L, Laznickova A, Laznicek M. Preclinical evaluation of gastrin derivatives labelled with 111In: radiolabelling, affinity profile and pharmacokinetics in rats. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2013; 158:544-51. [PMID: 24108197 DOI: 10.5507/bp.2013.064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 08/22/2013] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Cholecystokinin receptor subtype 2 (CCK-2) is overexpressed in various tumours like medullary thyroid carcinomas and small cell lung cancer. Radiolabelled peptides that bind with high affinity and specificity to CCK-2 receptors, thus hold great potential for visualizing such tumours. METHODS We compared four 111In labelled gastrin analogues, called minigastrins (MG), namely MG11, MG45, MG47 and MG48 linked to metal chelating DOTA in preclinical experiments. The radiolabelled peptides were tested for peptide binding in CCK-2 receptor-bearing cell line AR42J and for their pharmacokinetics in normal rats. RESULTS The experiments suggest that all gastrin analogues had similar and relatively rapid internalization into AR42J cells. Binding to CCK-2 receptors in AR42J cells was saturable for all agents but there were some differences in receptor affinity. This biodistribution study in rats showed a rapid decrease in blood radioactivity, predominantly renal clearance and saturable uptake of the radiopharmaceutical and/or its metabolites in the CCK-2 receptor-positive stomach. Higher kidney accumulation of radioactivity was only found for 111In-DOTA-minigastrin 48. CONCLUSIONS The data suggest that the 111In-DOTA-minigastrin analogues studied are promising candidates for the scintigraphy of CCK-2 receptor-expressing tumours; 111In-DOTA-MG47 and 111In-DOTA-MG11 are the most promising.
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Affiliation(s)
- Ludmila Melicharova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
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Abstract
C-terminally amidated gastrins act at cholecystokinin-2 receptors (CCK2R), which are normally expressed by gastric parietal and enterochromaffin-like (ECL) cells and smooth muscle; there is also extensive expression in the CNS where the main endogenous ligand is cholecystokinin. A variety of neoplasms express CCK2R, or splice variants, including neuroendocrine, pancreatic, medullary thyroid and lung cancers. Other products of the gastrin gene (progastrin, the Gly-gastrins) may stimulate cell proliferation but are not CCK2R ligands. Depending on the cell type, stimulation of CCK2R evokes secretion, increases proliferation and cell migration, inhibits apoptosis, and controls the expression of various genes. These effects are mediated by increased intracellular calcium and activation of protein kinase C, MAPkinase and other protein kinase cascades. There has been recent progress in developing CCK2R ligands that can be used for imaging tumours expressing the receptor. New antagonists have also been developed, and there is scope for using these for suppression of gastric acid and for treatment of neuroendocrine and other CCK2R-expressing tumours.
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Laverman P, Sosabowski JK, Boerman OC, Oyen WJG. Radiolabelled peptides for oncological diagnosis. Eur J Nucl Med Mol Imaging 2012; 39 Suppl 1:S78-92. [PMID: 22388627 PMCID: PMC3304069 DOI: 10.1007/s00259-011-2014-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The 111In-labelled somatostatin analogue octreotide (OctreoScan™) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours.
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Affiliation(s)
- Peter Laverman
- Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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Baum RP, Kulkarni HR, Carreras C. Peptides and Receptors in Image-Guided Therapy: Theranostics for Neuroendocrine Neoplasms. Semin Nucl Med 2012; 42:190-207. [DOI: 10.1053/j.semnuclmed.2012.01.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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