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Aloj L, Mansi R, De Luca S, Accardo A, Tesauro D, Morelli G. Radiolabeled peptides and their expanding role in clinical imaging and targeted cancer therapy. J Pept Sci 2024:e3607. [PMID: 38710638 DOI: 10.1002/psc.3607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/29/2024] [Accepted: 04/01/2024] [Indexed: 05/08/2024]
Abstract
There is an expanding body of evidence showing that synthetic peptides in combination with radioactive isotopes can be utilized for medical purposes. This area is of particular interest in oncology where applications in diagnosis and therapy are at different stages of development. We review the contributions in this area by the group originally founded by Carlo Pedone in Naples many years ago. We highlight the work of this group in the context of other developments in this area, focusing on three biologically relevant receptor systems: somatostatin, gastrin-releasing peptide, and cholecystokinin-2/gastrin receptors. We focus on key milestones, state of the art, and challenges in this area of research as well as the current and future outlook for expanding clinical applications.
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Affiliation(s)
- Luigi Aloj
- Department of Radiology, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Rosalba Mansi
- Division of Radiopharmaceutical Chemistry, Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland
| | - Stefania De Luca
- Institute of Biostructures and Bioimaging (IBB), CNR, Naples, Italy
| | - Antonella Accardo
- Department of Pharmacy and CIRPeB, Research Centre on Bioactive Peptides "Carlo Pedone", University of Naples "Federico II", Naples, Italy
| | - Diego Tesauro
- Department of Pharmacy and CIRPeB, Research Centre on Bioactive Peptides "Carlo Pedone", University of Naples "Federico II", Naples, Italy
| | - Giancarlo Morelli
- Department of Pharmacy and CIRPeB, Research Centre on Bioactive Peptides "Carlo Pedone", University of Naples "Federico II", Naples, Italy
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2
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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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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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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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Khan NUH, Corlett A, Hutton CA, Haskali MB. Investigation of Fluorine-18 Labelled Peptides for Binding to Cholecystokinin-2 Receptors with High Affinity. Int J Pept Res Ther 2021. [DOI: 10.1007/s10989-021-10310-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
AbstractMany cancers of neuroendocrine origin overexpress cholecystokinin-2 receptors (CCK-2R) including medullary thyroid cancer, small cell lung cancer and other lung carcinoids. Fluorine-18 labelled peptides targeting CCK-2R enable direct visualization and quantification of this receptor in vivo using positron emission tomography imaging. CP04 1 and MG11 2 are two previously described truncated peptides derived from the native CCK-2R hormone ligand, gastrin. The N-terminus of the MG11 2 octopeptide was chemically modified with various fluorine containing aromatic (4-fluorobenzoate), heterocyclic (6-fluoronicotinate) and aliphatic (2-fluoropropionate) moieties. To assess the impact these modifications had on CCK-2R binding, ligand-binding assays were conducted using A431 cells overexpressing human CCK-2R. MG11 2 modified by 4-fluorobenzoate (FB-MG11 3) demonstrated the highest binding affinity (0.20 nM) followed by MG11 2 modified by 6-fluoronicotinate (FNic-MG11 4; 0.74 nM) and 2-fluoropropionate (FP-MG11 5; 1.80 nM), respectively. Whilst indirect labelling of MG11 2 using fluorine-18 labelled activated esters of fluorobenzoate and 6-fluoronicotinate was unsuccessful, direct fluorine-18 labelling at the N-terminus modified with 6-nitronicotinate afforded a 47.6% radiochemical yield of [18F]FNic-MG11. Unfortunately, [18F]FNic-MG11 4 was chemically unstable, decomposing slowly through defluorination, thereby impeding any further work with this radiotracer.
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Update on Preclinical Development and Clinical Translation of Cholecystokinin-2 Receptor Targeting Radiopharmaceuticals. Cancers (Basel) 2021; 13:cancers13225776. [PMID: 34830930 PMCID: PMC8616406 DOI: 10.3390/cancers13225776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Peptide analogs, derived from the natural peptide hormone gastrin, are promising candidates for improving the visualization and treatment of tumors. Gastrin specifically binds to the cholecystokinin-2 receptor, a G-protein-coupled receptor expressed on the cell surface of different tumors. This enables specific targeting of tumor cells using gastrin analogs, labeled with radioisotopes. The receptor is expressed at high incidence in medullary thyroid carcinoma, a rare form of thyroid cancer lacking effective treatments at an advanced stage. Different radiolabeled gastrin analogs as well as nonpeptidic compounds targeting CCK2R have been developed. Specific modifications have been introduced in order to safely deliver the radiation to the tumor site. In this review, recent strategies applied to improve the targeting properties are described. These developments enabled the introduction of new radiolabeled peptide analogs for imaging and therapy in cancer patients. In addition to highlighting the current clinical trials, the perspectives for future applications are given. Abstract The cholecystokinin-2 receptor (CCK2R) has been a target of interest for molecular imaging and targeted radionuclide therapy for two decades. However, so far CCK2R targeted imaging and therapy has not been introduced in clinical practice. Within this review the recent radiopharmaceutical development of CCK2R targeting compounds and the ongoing clinical trials are presented. Currently, new gastrin derivatives as well as nonpeptidic substances are being developed to improve the properties for clinical use. A team of specialists from the field of radiopharmacy and nuclear medicine reviewed the available literature and summarized their own experiences in the development and clinical testing of CCK2R targeting radiopharmaceuticals. The recent clinical trials with novel radiolabeled minigastrin analogs demonstrate the potential for both applications, imaging as well as targeted radiotherapy, and reinforce the clinical applicability within a theranostic concept. The intense efforts in optimizing CCK2R targeting radiopharmaceuticals has led to new substances for clinical use, as shown in first imaging studies in patients with advanced medullary thyroid cancer. The first clinical results suggest that the wider clinical implication of CCK2R-targeted radiopharmaceuticals is reasonable.
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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 2021; 27:7112-7132. [PMID: 32586246 DOI: 10.2174/0929867327666200625143035] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [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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Klingler M, Hörmann AA, Rangger C, Desrues L, Castel H, Gandolfo P, von Guggenberg E. Stabilization Strategies for Linear Minigastrin Analogues: Further Improvements via the Inclusion of Proline into the Peptide Sequence. J Med Chem 2020; 63:14668-14679. [PMID: 33226806 PMCID: PMC7734625 DOI: 10.1021/acs.jmedchem.0c01233] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Minigastrin (MG) analogues, known for their high potential to target cholecystokinin-2 receptor (CCK2R) expressing tumors, have limited clinical applicability due to low enzymatic stability. By introducing site-specific substitutions within the C-terminal receptor-binding sequence, reduced metabolization and improved tumor targeting can be achieved. In this work, the influence of additional modification within the N-terminal sequence has been explored. Three novel 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated CCK2R ligands with proline substitution at different positions were synthesized. Substitution did not affect CCK2R affinity, and the conjugates labeled with indium-111 and lutetium-177 showed a high enzymatic stability in different incubation media as well as in vivo (57-79% intact radiopeptide in blood of BALB/c mice at 1 h p.i.) combined with enhanced tumor uptake (29-46% IA/g at 4 h in xenografted BALB/c nude mice). The inclusion of Pro contributes significantly to the development of CCK2R ligands with optimal targeting properties for application in targeted radiotherapy.
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Affiliation(s)
- Maximilian Klingler
- Department of Nuclear Medicine, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Anton A Hörmann
- Department of Nuclear Medicine, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Christine Rangger
- Department of Nuclear Medicine, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Laurence Desrues
- INSERM U1239, DC2N, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandy, 76000 Rouen, France
| | - Hélène Castel
- INSERM U1239, DC2N, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandy, 76000 Rouen, France
| | - Pierrick Gandolfo
- INSERM U1239, DC2N, Institute for Research and Innovation in Biomedicine (IRIB), University of Rouen Normandy, 76000 Rouen, France
| | - Elisabeth von Guggenberg
- Department of Nuclear Medicine, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
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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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Rizvi SFA, Mu S, Wang Y, Li S, Zhang H. Fluorescent RGD-based pro-apoptotic peptide conjugates as mitochondria-targeting probes for enhanced anticancer activities. Biomed Pharmacother 2020; 127:110179. [PMID: 32387862 DOI: 10.1016/j.biopha.2020.110179] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/17/2020] [Accepted: 04/19/2020] [Indexed: 01/10/2023] Open
Abstract
We have designed 2-domain anticancer peptides with RGD-based KLAK bi-functional short motifs (linear and cyclic analogues). RGD tripeptide acts as tumor blood vessel 'homing' motif while KLAK tetrapeptide internalized in mitochondria and causes cell apoptosis. All three peptides (RGDKLAK; HM, cyclic-RGDKLAK; HMC-1, and RGD-cyclic-KLAK; HMC-2) were conjugated with fluorescein isothiocyanate isomer-I (5-FITC; F) for in-vivo and in-vitro optical imaging studies. These fluorescent-peptide (FL-peptide) analogues were analyzed to possess αvβ3-integrin targeting affinity, high uptake in in-vitro cell binding assays followed by in-vivo tumor xenograft mice studies. Pharmacological profile reveals that F-HMC-1 analogue exhibited selectively and specifically higher affinity for αvβ3-integrin than other analogues in U87MG cells in comparison with HeLa cells. The subcutaneous U87MG tumor xenograft mice models clearly visualized the uptake of F-HMC-1 in tumor tissue in contrast with normal tissues with tumor-to-normal tissue ratio (T/NT = 15.9 ± 1.1) at 2 h post-injection. These results suggested that F-HMC-1 peptide has potential diagnostic applications for targeting αvβ3-integrin assessed by optical imaging study in U87MG tumor xenograft mice models.
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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, Lanzhou, 730000, PR China
| | - Shuai Mu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, PR China
| | - Yaya Wang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, PR China
| | - Shuangqin Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, PR China
| | - Haixia Zhang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, PR China.
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Farzipour S, Hosseinimehr SJ. Correlation between in vitro and in vivo Data of Radiolabeled Peptide for Tumor Targeting. Mini Rev Med Chem 2019; 19:950-960. [DOI: 10.2174/1389557519666190304120011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/28/2018] [Accepted: 02/22/2019] [Indexed: 12/12/2022]
Abstract
Tumor-targeting peptides have been generally developed for the overexpression of tumor specific receptors in cancer cells. The use of specific radiolabeled peptide allows tumor visualization by single photon emission computed tomography (SPECT) and positron emission tomography (PET) tools. The high affinity and specific binding of radiolabeled peptide are focusing on tumoral receptors. The character of the peptide itself, in particular, its complex molecular structure and behaviors influence on its specific interaction with receptors which are overexpressed in tumor. This review summarizes various strategies which are applied for the expansion of radiolabeled peptides for tumor targeting based on in vitro and in vivo specific tumor data and then their data were compared to find any correlation between these experiments. With a careful look at previous studies, it can be found that in vitro unblock-block ratio was unable to correlate the tumor to muscle ratio and the success of radiolabeled peptide for in vivo tumor targeting. The introduction of modifiers’ approaches, nature of peptides, and type of chelators and co-ligands have mixed effect on the in vitro and in vivo specificity of radiolabeled peptides.
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Affiliation(s)
- Soghra Farzipour
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Seyed Jalal Hosseinimehr
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
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Cholecystokinin-2 Receptor Targeting with Novel C-terminally Stabilized HYNIC-Minigastrin Analogs Radiolabeled with Technetium-99m. Pharmaceuticals (Basel) 2019; 12:ph12010013. [PMID: 30650563 PMCID: PMC6469167 DOI: 10.3390/ph12010013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 12/19/2022] Open
Abstract
The high overexpression of cholecystokinin-2 receptors (CCK2R) in tumors, such as medullary thyroid carcinoma, allows for highly specific diagnostic and therapeutic targeting with radiolabeled peptide probes derived from natural ligands for the receptor. Based on the ideal imaging characteristics, high availability and low cost of technetium-99m (99mTc)-labeled radiopharmaceuticals we have developed two hydrazinonicotinic acid (HYNIC) conjugated minigastrin analogs allowing labeling at high specific activity. The CCK2R targeting peptide conjugates show specific amino acid substitutions in the C-terminal receptor-specific sequence with the aim to increase stability and tumor targeting. The CCK2R affinity and the cell uptake of the new radioligands were analyzed using A431 human epidermoid carcinoma cells stably transfected with human CCK2R and mock transfected cells. Metabolic studies in BALB/c mice revealed a high resistance against enzymatic degradation for both radioligands. Biodistribution studies in tumor-xenografted athymic BALB/c nude mice at 1 h and 4 h p.i. showed that the two 99mTc-labeled compounds showed varying uptake in receptor expressing organs, stomach and pancreas (1.3–10.4% IA/g), as well as kidneys, the main route of excretion (7.8–19.9% IA/g). The tumor uptake in A431-CCK2R xenografts was 24.75 ± 4.38% IA/g for [99mTc]Tc-HYNIC-MGS5 and 42.48 ± 6.99% IA/g for [99mTc]Tc-HYNIC-MGS11 at 4 h p.i., whereas the tumor-to-kidney ratio was comparable (2.6–3.3). On demand availability and potential application for radioguided surgery of a 99mTc-labeled minigastrin analog support the further evaluation of these highly promising new compounds.
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13
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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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Rezazadeh F, Sadeghzadeh N. Tumor targeting with 99m Tc radiolabeled peptides: Clinical application and recent development. Chem Biol Drug Des 2018; 93:205-221. [PMID: 30299570 DOI: 10.1111/cbdd.13413] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/19/2018] [Accepted: 09/23/2018] [Indexed: 01/16/2023]
Abstract
Targeting overexpressed receptors on the cancer cells with radiolabeled peptides has become very important in nuclear oncology in the recent years. Peptides are small and have easy preparation and easy radiolabeling protocol with no side-effect and toxicity. These properties made them a valuable tool for tumor targeting. Based on the successful imaging of neuroendocrine tumors with 111 In-octreotide, other receptor-targeting peptides such as bombesin (BBN), cholecystokinin/gastrin analogues, neurotensin analogues, glucagon-like peptide-1, and RGD peptides are currently under development or undergoing clinical trials. The most frequently used radionuclides for tumor imaging are 99m Tc and 111 In for single-photon emission computed tomography and 68 Ga and 18 F for positron emission tomography imaging. This review presents some of the 99m Tc-labeled peptides, with regard to their potential for radionuclide imaging of tumors in clinical and preclinical application.
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Affiliation(s)
- Farzaneh Rezazadeh
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Nourollah Sadeghzadeh
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
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15
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Multimerization results in formation of re-bindable metabolites: A proof of concept study with FSC-based minigastrin imaging probes targeting CCK2R expression. PLoS One 2018; 13:e0201224. [PMID: 30059514 PMCID: PMC6066219 DOI: 10.1371/journal.pone.0201224] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 07/11/2018] [Indexed: 12/21/2022] Open
Abstract
Positron emission tomography (PET) with radiolabelled peptide-based tracers has attracted great interest in oncology over the past decades. The success of imaging is closely related to sufficient uptake of the radiotracer in malignant tissue and for this sufficient biological half-life, particularly in the bloodstream, is mandatory. Fast enzymatic degradation during circulation leading to insufficient imaging abilities of peptide-based radioligands remains a major issue. The design of multimeric constructs, bearing multiple targeting moieties, has been widely applied to improve target interaction. This concept may also be applied to prolong the biological half-life of peptide-based radiopharmaceuticals as enzymatic degradation can result in formation of metabolites still capable to interact with the target binding site. In this study we aimed to identify such metabolites and therefore we utilized the siderophore-based bifunctional chelator fusarinine C (FSC) for the design of novel mono- and multimeric constructs, bearing minigastrin (MG) analogues as targeting moieties to address cholecystokinin-2 receptors (CCK2R) which are overexpressed in a variety of cancerous diseases and are well known for fast enzymatic degradation, particularly for truncated des-(Glu)5-MG members, such as MG11. FSC-based imaging probes were radiolabelled with gallium-68 and characterized in vitro (logD, protein binding, affinity and cell-uptake studies, stability and metabolite studies, as well as generation of corresponding metabolites by artificial enzymatic degradation) and in vivo (biodistribution in A431-CCK2R/A431-mock tumour xenografted BALB/c nude mice and stability in blood of living BALB/c mice and analysis of corresponding organ homogenates and urine to identify degradation products). In summary, multimerization was accompanied by partial improvement towards targeting abilities. Identified metabolites formed by artificial enzymatic cleavage of trimeric FSC-MG conjugates in vitro contained intact binding sequences for the receptor. Furthermore, the 68Ga-labelled trimers exhibiting increasing uptake of radioligand in tumour tissue over time and improved in vivo stability in blood samples of living animals of the trimers compared to corresponding mono- and dimers, strongly supporting our hypothesis.
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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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Lipiński PFJ, Garnuszek P, Maurin M, Stoll R, Metzler-Nolte N, Wodyński A, Dobrowolski JC, Dudek MK, Orzełowska M, Mikołajczak R. Structural studies on radiopharmaceutical DOTA-minigastrin analogue (CP04) complexes and their interaction with CCK2 receptor. EJNMMI Res 2018; 8:33. [PMID: 29663167 PMCID: PMC5902437 DOI: 10.1186/s13550-018-0387-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 04/06/2018] [Indexed: 12/16/2022] Open
Abstract
Background The cholecystokinin receptor subtype 2 (CCK-2R) is an important target for diagnostic imaging and targeted radionuclide therapy (TRNT) due to its overexpression in certain cancers (e.g., medullary thyroid carcinoma (MTC)), thus matching with a theranostic principle. Several peptide conjugates suitable for the TRNT of MTC have been synthesized, including a very promising minigastrin analogue DOTA-(DGlu)6-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 (CP04). In this contribution, we wanted to see whether CP04 binding affinity for CCK-2R is sensitive to the type of the complexed radiometal, as well as to get insights into the structure of CP04-CCK2R complex by molecular modeling. Results In vitro studies demonstrated that there is no significant difference in CCK-2R binding affinity and specific cellular uptake between the CP04 conjugates complexed with [68Ga]Ga3+ or [177Lu]Lu3+. In order to investigate the background of this observation, we proposed a binding model of CP04 with CCK-2R based on homology modeling and molecular docking. In this model, the C-terminal part of the molecule enters the cavity formed between the receptor helices, while the N-terminus (including DOTA and the metal) is located at the binding site outlet, exposed in large extent to the solvent. The radiometals do not influence the conformation of the molecule except for the direct neighborhood of the chelating moiety. Conclusions The model seems to be in agreement with much of structure-activity relationship (SAR) studies reported for cholecystokinin and for CCK-2R-targeting radiopharmaceuticals. It also explains relative insensitivity of CCK-2R affinity for the change of the metal. The proposed model partially fits the reported site-directed mutagenesis data.
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Affiliation(s)
- Piotr F J Lipiński
- Neuropeptides Department, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5 Str., 02-106, Warszawa, Poland.
| | - Piotr Garnuszek
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, A. Sołtana 7 Str, 05-400, Otwock, Poland
| | - Michał Maurin
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, A. Sołtana 7 Str, 05-400, Otwock, Poland
| | - Raphael Stoll
- Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Nils Metzler-Nolte
- Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Artur Wodyński
- Świerk Computing Centre, National Centre for Nuclear Research, A. Sołtana 7 Str., 05-400, Otwock, Poland.,Institut für Chemie, Theoretische Chemie/Quantenchemie, Technische Universität Berlin, Sekr. C7, Strasse des 17. Juni 135, 10623, Berlin, Germany
| | - Jan Cz Dobrowolski
- Institute of Nuclear Chemistry and Technology, Dorodna 16 Street, 03-195, Warszawa, Poland.,National Medicines Institute, Chełmska 30/34 Str., 00-725, Warszawa, Poland
| | - Marta K Dudek
- Centre of Molecular and Macromolecular Studies Polish Academy of Sciences, Sienkiewicza 112, 90-363, Lodz, Poland
| | - Monika Orzełowska
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, A. Sołtana 7 Str, 05-400, Otwock, Poland
| | - Renata Mikołajczak
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, A. Sołtana 7 Str, 05-400, Otwock, Poland
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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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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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20
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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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Zarschler K, Rocks L, Licciardello N, Boselli L, Polo E, Garcia KP, De Cola L, Stephan H, Dawson KA. Ultrasmall inorganic nanoparticles: State-of-the-art and perspectives for biomedical applications. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2016; 12:1663-701. [PMID: 27013135 DOI: 10.1016/j.nano.2016.02.019] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/08/2016] [Accepted: 02/15/2016] [Indexed: 12/31/2022]
Abstract
Ultrasmall nanoparticulate materials with core sizes in the 1-3nm range bridge the gap between single molecules and classical, larger-sized nanomaterials, not only in terms of spatial dimension, but also as regards physicochemical and pharmacokinetic properties. Due to these unique properties, ultrasmall nanoparticles appear to be promising materials for nanomedicinal applications. This review overviews the different synthetic methods of inorganic ultrasmall nanoparticles as well as their properties, characterization, surface modification and toxicity. We moreover summarize the current state of knowledge regarding pharmacokinetics, biodistribution and targeting of nanoscale materials. Aside from addressing the issue of biomolecular corona formation and elaborating on the interactions of ultrasmall nanoparticles with individual cells, we discuss the potential diagnostic, therapeutic and theranostic applications of ultrasmall nanoparticles in the emerging field of nanomedicine in the final part of this review.
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Affiliation(s)
- Kristof Zarschler
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden - Rossendorf, Bautzner Landstraße 400, Dresden, Germany.
| | - Louise Rocks
- Centre For BioNano Interactions (CBNI), School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Nadia Licciardello
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden - Rossendorf, Bautzner Landstraße 400, Dresden, Germany; Laboratoire de Chimie et des Biomatériaux Supramoléculaires, Institut de Science et d'Ingénierie Supramoléculaires (ISIS), 8 allée Gaspard Monge, Strasbourg, France; Institut für Nanotechnologie (INT), Karlsruher Institut für Technologie (KIT) Campus North, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, Germany
| | - Luca Boselli
- Centre For BioNano Interactions (CBNI), School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ester Polo
- Centre For BioNano Interactions (CBNI), School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Karina Pombo Garcia
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden - Rossendorf, Bautzner Landstraße 400, Dresden, Germany
| | - Luisa De Cola
- Laboratoire de Chimie et des Biomatériaux Supramoléculaires, Institut de Science et d'Ingénierie Supramoléculaires (ISIS), 8 allée Gaspard Monge, Strasbourg, France; Institut für Nanotechnologie (INT), Karlsruher Institut für Technologie (KIT) Campus North, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, Germany
| | - Holger Stephan
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden - Rossendorf, Bautzner Landstraße 400, Dresden, Germany
| | - Kenneth A Dawson
- Centre For BioNano Interactions (CBNI), School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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(99m)Tc-labeled gastrins of varying peptide chain length: Distinct impact of NEP/ACE-inhibition on stability and tumor uptake in mice. Nucl Med Biol 2016; 43:347-54. [PMID: 27260775 DOI: 10.1016/j.nucmedbio.2016.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 03/14/2016] [Indexed: 01/24/2023]
Abstract
INTRODUCTION In situ inhibition of neutral endopeptidase (NEP) has been recently shown to impressively increase the bioavailability and tumor uptake of biodegradable gastrin radioligands. Furthermore, angiotensin converting enzyme (ACE) has been previously shown to cleave gastrin analogs in vitro. In the present study, we have assessed the effects induced by single or dual NEP/ACE-inhibition on the pharmacokinetic profile of three (99m)Tc-labeled gastrins of varying peptide chain length: [(99m)Tc]SG6 ([(99m)Tc-N4-Gln(1)]gastrin(1-17)), [(99m)Tc]DG2 ([(99m)Tc-N4-Gly(4),DGlu(5)]gastrin(4-17)) and [(99m)Tc]DG4 ([(99m)Tc-N4-DGlu(10)]gastrin(10-17)). METHODS Mouse blood samples were collected 5min after injection of each of [(99m)Tc]SG6/DG2/DG4 together with: a) vehicle, b) the NEP-inhibitor phosphoramidon (PA), c) the ACE-inhibitor lisinopril (Lis), or d) PA plus Lis and were analyzed by RP-HPLC for radiometabolite detection. Biodistribution was studied in SCID mice bearing A431-CCK2R(+/-) xenografts at 4h postinjection (pi). [(99m)Tc]SG6 or [(99m)Tc]DG4 was coinjected with either vehicle or the above described NEP/ACE-inhibitor regimens; for [(99m)Tc]DG2 control and PA animal groups were only included. RESULTS Treatment of mice with PA induced significant stabilization of (99m)Tc-radiotracers in peripheral blood, while treatment with Lis or Lis+PA affected the stability of des(Glu)5 [(99m)Tc]DG4 only. In line with these findings, PA coinjection led to notable amplification of tumor uptake of radiopeptides compared to controls (P<0.01). Only [(99m)Tc]DG4 profited by single Lis (2.06±0.39%ID/g vs 0.99±0.13%ID/g in controls) or combined Lis+PA coinjection (8.91±1.61%ID/g vs 4.89±1.33%ID/g in PA-group). Furthermore, kidney uptake remained favourably low and unaffected by PA and/or Lis coinjection only in the case of [(99m)Tc]DG4 (<1.9%ID/g) resulting in the most optimal tumor-to-kidney ratios. CONCLUSIONS In situ NEP/ACE-inhibition diversely affected the in vivo profile of (99m)Tc-radioligands based on different-length gastrins. Truncated [(99m)Tc]DG4 exhibited overall the most attractive profile during combined NEP/ACE-inhibition in mouse models, providing new opportunities for CCK2R-expressing tumor imaging in man with SPECT.
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Pawlak D, Rangger C, Kolenc Peitl P, Garnuszek P, Maurin M, Ihli L, Kroselj M, Maina T, Maecke H, Erba P, Kremser L, Hubalewska-Dydejczyk A, Mikołajczak R, Decristoforo C. From preclinical development to clinical application: Kit formulation for radiolabelling the minigastrin analogue CP04 with In-111 for a first-in-human clinical trial. Eur J Pharm Sci 2016; 85:1-9. [PMID: 26826279 PMCID: PMC4817208 DOI: 10.1016/j.ejps.2016.01.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 01/16/2016] [Accepted: 01/24/2016] [Indexed: 01/07/2023]
Abstract
Introduction A variety of radiolabelled minigastrin analogues targeting the cholecystokinin 2 (CCK2) receptor were developed and compared in a concerted preclinical testing to select the most promising radiotracer for diagnosis and treatment of medullary thyroid carcinoma (MTC). DOTA–DGlu–DGlu–DGlu–DGlu–DGlu–DGlu– Ala–Tyr–Gly–Trp–Met–Asp–Phe–NH2 (CP04) after labelling with 111In displayed excellent characteristics, such as high stability, receptor affinity, specific and persistent tumour uptake and low kidney retention in animal models. Therefore, it was selected for further clinical evaluation within the ERA-NET project GRAN-T-MTC. Here we report on the development of a pharmaceutical freeze-dried formulation of the precursor CP04 for a first multi-centre clinical trial with 111In-CP04 in MTC patients. Materials and methods The kit formulation was optimised by adjustment of buffer, additives and radiolabelling conditions. Three clinical grade batches of a final kit formulation with two different amounts of peptide (10 or 50 μg) were prepared and radiolabelled with 111In. Quality control and stability assays of both the kits and the resulting radiolabelled compound were performed by HPLC analysis. Results Use of ascorbic acid buffer (pH 4.5) allowed freeze-drying of the kit formulation with satisfactory pellet-formation. Addition of methionine and gentisic acid as well as careful selection of radiolabelling temperature was required to avoid extensive oxidation of the Met11-residue. Trace metal contamination, in particular Zn, was found to be a major challenge during the pharmaceutical filling process in particular for the 10 μg formulation. The final formulations contained 10 or 50 μg CP04, 25 mg ascorbic acid, 0.5 mg gentisic acid and 5 mg l-methionine. The radiolabelling performed by incubation of 200–250 MBq 111InCl3 at 90 °C for 15 min resulted in reproducible radiochemical purity (RCP) >94%. Kit-stability was proven for >6 months at +5 °C and at +25 °C. The radiolabelled product was stable for >4 h at +25 °C. Conclusion A kit formulation to prepare 111In-CP04 for clinical application was developed, showing high stability of the kit as well as high RCP of the final product.
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Affiliation(s)
- Dariusz Pawlak
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, Otwock, Poland
| | | | - Petra Kolenc Peitl
- Dept. of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia
| | - Piotr Garnuszek
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, Otwock, Poland
| | - Michał Maurin
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, Otwock, Poland
| | - Laura Ihli
- Dept. of Nuclear Medicine, Medical University Innsbruck, Austria
| | - Marko Kroselj
- Dept. of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Athens, Greece
| | - Helmut Maecke
- Dept. of Nuclear Medicine, University Hospital Freiburg, Germany
| | - Paola Erba
- Dept. of Nuclear Medicine, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy
| | - Leopold Kremser
- Division of Clinical Biochemistry, Biocenter, Medical University Innsbruck, Austria
| | | | - Renata Mikołajczak
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, Otwock, Poland
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Pfister J, Summer D, Rangger C, Petrik M, von Guggenberg E, Minazzi P, Giovenzana GB, Aloj L, Decristoforo C. Influence of a novel, versatile bifunctional chelator on theranostic properties of a minigastrin analogue. EJNMMI Res 2015; 5:74. [PMID: 26669693 PMCID: PMC4679714 DOI: 10.1186/s13550-015-0154-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 12/10/2015] [Indexed: 01/21/2023] Open
Abstract
Background 6-[Bis(carboxymethyl)amino]-1,4-bis(carboxymethyl)-6-methyl-1,4-diazepane (AAZTA ) is a promising chelator with potential advantages over 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) for radiopharmaceutical applications. Its mesocyclic structure enables fast radiolabelling under mild conditions with trivalent metals including not only 68Ga for positron emission tomography (PET) but also 177Lu and 111In for single-photon emission computed tomography (SPECT) and radionuclide therapy. Here, we describe the evaluation of a bifunctional AAZTA derivative conjugated to a model minigastrin derivative as a potential theranostic agent. Methods An AAZTA derivative with an aliphatic C9 chain as linker was coupled to a minigastrin, namely [AAZTA0, D-Glu1, desGlu2–6]-minigastrin (AAZTA-MG), and labelled with 68Ga, 177Lu and 111In. The characterisation in vitro included stability studies in different media and determination of logD (octanol/PBS). Affinity determination (IC50) and cell uptake studies were performed in A431-CCK2R cells expressing the human CCK2 receptor. μPET/CT and ex vivo biodistribution studies were performed in CCK2 tumour xenograft-bearing nude mice and normal mice. Results AAZTA-MG showed high radiochemical yields for 68Ga (>95 %), 177Lu (>98 %) and 111In (>98 %). The logD value of −3.7 for both [68Ga]- and [177Lu]-AAZTA-MG indicates a highly hydrophilic character. Stability tests showed overall high stability in solution with some degradation in human plasma for [68Ga]- and transchelation towards DTPA for and [177Lu]-AAZTA-MG. An IC50 value of 10.0 nM was determined, which indicates a high affinity for the CCK2 receptor. Specific cell uptake after 60 min was >7.5 % for [68Ga]-AAZTA-MG and >9.5 % for [177Lu]-AAZTA-MG, comparable to other DOTA-MG-analogues. μPET/CT studies in CCK2 receptor tumour xenografted mice not only revealed high selective accumulation in A431-CCK2R positive tumours of 68Ga-labelled AAZTA-MG (1.5 % ID/g in 1 h post injection) but also higher blood levels as corresponding DOTA-analogues. The 111In-labelled peptide had a tumour uptake of 1.7 % ID/g. Biodistribution in normal mice with the [177Lu]-AAZTA-MG showed a considerable uptake in intestine (7.3 % ID/g) and liver (1.5 % ID/g). Conclusion Overall, AAZTA showed interesting properties as bifunctional chelator for peptides providing mild radiolabelling conditions for both 68Ga and trivalent metals having advantages over the currently used chelator DOTA. Studies are ongoing to further investigate in vivo targeting properties and stability issues and the influence of spacer length on biodistribution of AAZTA. Electronic supplementary material The online version of this article (doi:10.1186/s13550-015-0154-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Joachim Pfister
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria
| | - Dominik Summer
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria
| | - Christine Rangger
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria
| | - Milos Petrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Elisabeth von Guggenberg
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria
| | | | - Giovanni B Giovenzana
- CAGE Chemicals srl, Novara, Italy.,DSF, Università del Piemonte Orientale "A. Avogadro", Novara, Italy
| | - Luigi Aloj
- Division of Nuclear Medicine, Istituto Nazionale Tumori, "Fondazione G. Pascale"-IRCCS, Napoli, Italy
| | - Clemens Decristoforo
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria.
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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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von Guggenberg E, Rangger C, Sosabowski J, Laverman P, Reubi JC, Virgolini IJ, Decristoforo C. Preclinical evaluation of radiolabeled DOTA-derivatized cyclic minigastrin analogs for targeting cholecystokinin receptor expressing malignancies. Mol Imaging Biol 2012; 14:366-75. [PMID: 21732165 DOI: 10.1007/s11307-011-0506-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Targeting of cholecystokinin receptor expressing malignancies such as medullary thyroid carcinoma is currently limited by low in vivo stability of radioligands. To increase the stability, we have developed and preclinically evaluated two cyclic 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-minigastrin analogs radiolabeled with (111)In and (68)Ga. PROCEDURES Radiolabeling efficiency, in vitro characterization, cholecystokinin receptor subtype 2 (CCK-2) binding in human tumor tissues, and cell internalization on CCK-2 receptor expressing AR42J cells, as well as biodistribution and small animal imaging in two different mouse xenograft models were studied. RESULTS High receptor affinity and receptor-mediated uptake of the radioligands in AR42J cells was confirmed in vitro. (111)In-labeled cyclic DOTA-peptides showed a specific tumor uptake of ~1% ID/g in vivo, (68)Ga-labeled analogs of ~3% ID/g. Small animal SPECT imaging resulted to be superior with (111)In-DOTA-cyclo-MG2 in comparison with (111)In-DOTA-cyclo-MG1. CONCLUSIONS Cyclic DOTA-minigastrin analogs are promising candidates for gastrin receptor scintigraphy and targeted radionuclide therapy.
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Affiliation(s)
- Elisabeth von Guggenberg
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, 6020, Innsbruck, Austria.
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Trejtnar F, Laznickova A, Laznicek M, Novy Z, Maina T, Nock BA, Behe M. Distribution, elimination, and renal handling of (99m)technetium-Demogastrin 1. Cancer Biother Radiopharm 2012; 27:169-74. [PMID: 22409267 DOI: 10.1089/cbr.2011.1008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Radiolabeled cholecystokinin/gastrin (CCK) receptor-targeting peptides are promising compounds for radiodiagnosis and radiotherapy of certain malignancies. This study evaluated the pharmacokinetic profile of a CCK-2 receptor-specific peptide, Demogastrin 1, labeled with technetium-99m ((99m)Tc-Demogastrin 1), in rats. To investigate the fate of (99m)Tc-Demogastrin 1 in the rat, biodistribution and elimination studies in vivo were performed, and elimination parameters in perfused rat liver and kidney were determined. Biodistribution studies showed that (99m)Tc-Demogastrin 1 was rapidly cleared from the blood and most organs. A significant amount of radioactivity was detected in the CCK-2 receptor-rich organs, such as the stomach. Low radioactivity was found in the CCK-1 receptor-rich organs. Radioactivity in bowels and stomach declined relatively slowly. High and long-term retention of radioactivity in the kidneys was observed. Elimination of (99m)Tc-Demogastrin 1 via the bile was negligible. A high and rapid renal excretion was observed in elimination experiments in vivo. In the perfused kidney, glomerular filtration was found to be the main renal excretion mechanism of (99m)Tc-Demogastrin 1. Demogastrin 1 was distributed preferentially to the organs expressing CCK-2 receptors. The decisive elimination route of (99m)Tc-Demogastrin 1 in rats was urinary excretion. A high and prolonged renal retention may limit potential clinical use of the compound.
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Affiliation(s)
- Frantisek Trejtnar
- Faculty of Pharmacy, Charles University in Prague, Hradec Kralove, Czech Republic.
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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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Fani M, Maecke HR. Radiopharmaceutical development of radiolabelled peptides. Eur J Nucl Med Mol Imaging 2012; 39 Suppl 1:S11-30. [PMID: 22388624 DOI: 10.1007/s00259-011-2001-z] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Receptor targeting with radiolabelled peptides has become very important in nuclear medicine and oncology in the past few years. The overexpression of many peptide receptors in numerous cancers, compared to their relatively low density in physiological organs, represents the molecular basis for in vivo imaging and targeted radionuclide therapy with radiolabelled peptide-based probes. The prototypes are analogs of somatostatin which are routinely used in the clinic. More recent developments include somatostatin analogs with a broader receptor subtype profile or with antagonistic properties. Many other peptide families such as bombesin, cholecystokinin/gastrin, glucagon-like peptide-1 (GLP-1)/exendin, arginine-glycine-aspartic acid (RGD) etc. have been explored during the last few years and quite a number of potential radiolabelled probes have been derived from them. On the other hand, a variety of strategies and optimized protocols for efficient labelling of peptides with clinically relevant radionuclides such as (99m)Tc, M(3+) radiometals ((111)In, (86/90)Y, (177)Lu, (67/68)Ga), (64/67)Cu, (18)F or radioisotopes of iodine have been developed. The labelling approaches include direct labelling, the use of bifunctional chelators or prosthetic groups. The choice of the labelling approach is driven by the nature and the chemical properties of the radionuclide. Additionally, chemical strategies, including modification of the amino acid sequence and introduction of linkers/spacers with different characteristics, have been explored for the improvement of the overall performance of the radiopeptides, e.g. metabolic stability and pharmacokinetics. Herein, we discuss the development of peptides as radiopharmaceuticals starting from the choice of the labelling method and the conditions to the design and optimization of the peptide probe, as well as some recent developments, focusing on a selected list of peptide families, including somatostatin, bombesin, cholecystokinin/gastrin, GLP-1/exendin and RGD.
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Affiliation(s)
- Melpomeni Fani
- Department of Nuclear Medicine, University Hospital Freiburg, Hugstetterstrasse 55, 79106 Freiburg, Germany.
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Ocak M, Helbok A, von Guggenberg E, Ozsoy Y, Kabasakal L, Kremser L, Decristoforo C. Influence of biological assay conditions on stability assessment of radiometal-labelled peptides exemplified using a 177Lu-DOTA-minigastrin derivative. Nucl Med Biol 2011; 38:171-9. [PMID: 21315272 DOI: 10.1016/j.nucmedbio.2010.07.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Revised: 07/05/2010] [Accepted: 07/14/2010] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Lack of correlation between in vitro and in vivo stability is a general problem for the development of radiopeptides especially in the case of minigastrin derivatives for therapeutic applications. In this study, we compared the influence of experimental conditions on radiopeptide stability results in vitro using a model Minigastrin (MG) analogue labelled with Lu-177. Additionally, we attempted to characterize the main serum enzymatic cleavage sites by matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) analysis. METHODS In vitro stability of a DOTA-minigastrin derivative ((177)Lu-DOTA-His-His-Glu-Ala-Tyr-Gly-Trp-NIe-Asp-Phe-NH(2)) was tested in serum, rat tissue homogenates and two different standardised enzymatic mixtures. Quantification of the metabolised radiopeptides at different time intervals was performed using reversed-phase high-performance liquid chromatography (RP-HPLC). Metabolites were characterised by MALDI-TOF-MS. Urine was collected after 15 min p.i. into the mice and compared with in vitro metabolites by RP-HPLC. RESULTS Faster degradation of the radiopeptide was found in blood in comparison with plasma and serum incubation and in components from rats faster than from human origin. Fast degradation was observed in kidney and liver homogenates as well as in standardised enzymatic mixtures, also revealing variations in the metabolic profile. In urine, no intact peptide was detected already 5 min post injection. MALDI-TOF-MS revealed major cleavage sites at the carboxy terminus of the peptide. CONCLUSION Very variable results may be found when different kind of incubation media for testing radiopeptide stabilities is used. Serum incubation studies may overestimate stability; therefore, results should be interpreted with care and combined with alternative in vitro and in vivo investigations.
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Affiliation(s)
- Meltem Ocak
- Clinical Department of Nuclear Medicine, Medical University Innsbruck, A-6020, Innsbruck, Austria
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Comparison of the binding and internalization properties of 12 DOTA-coupled and ¹¹¹In-labelled CCK2/gastrin receptor binding peptides: a collaborative project under COST Action BM0607. Eur J Nucl Med Mol Imaging 2011; 38:1417-25. [PMID: 21523391 DOI: 10.1007/s00259-011-1816-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 04/04/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE Specific overexpression of cholecystokinin 2 (CCK2)/gastrin receptors has been demonstrated in several tumours of neuroendocrine origin. In some of these cancer types, such as medullary thyroid cancer (MTC), a sensitive diagnostic modality is still unavailable and therapeutic options for inoperable lesions are needed. Peptide receptor radionuclide therapy (PRRT) may be a viable therapeutic strategy in the management of these patients. Several CCK2R-targeted radiopharmaceuticals have been described in recent years. As part of the European Union COST Action BM0607 we studied the in vitro and in vivo characteristics of 12 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated CCK2R binding peptides. In the present study, we analysed binding and internalization characteristics. Stability, biodistribution and imaging studies have been performed in parallel by other centres involved in the project. METHODS Determination of IC(50) values was performed using autoradiography, with DOTA-peptides displacing (125)I-CCK from receptors on tissue sections from human tumours. Saturation binding and internalization experiments were performed using (111)In-labelled peptides. The rat AR42J cell line and the human A431-CCK2R transfected cell line were utilized for in vitro experiments; dissociation constants (K(d)) and apparent number of binding sites (B(max)) were determined. Internalization was determined in receptor-expressing cells by incubating with tracer amounts of peptide at 37 and 4°C for different times up to 120 min. Surface-bound peptide was then stripped either by acid wash or subsequent incubation with 1 μM unlabelled peptide at 4°C. RESULTS All peptides showed high receptor affinity with IC(50) values ranging from 0.2 to 3.4 nM. Saturation experiments also showed high affinity with K(d) values in the 10(-9)-10(-8) M range. B(max) values estimated in A431-CCK2R cells ranged from 0.6 to 2.2 × 10(6) per cell. All peptides showed high levels of internalization when incubated at 37°C. CONCLUSION All DOTA-conjugated peptides showed high receptor binding and internalization properties and appear suitable for further characterization, as described in other articles of this issue.
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Comparative biodistribution of 12 ¹¹¹In-labelled gastrin/CCK2 receptor-targeting peptides. Eur J Nucl Med Mol Imaging 2011; 38:1410-6. [PMID: 21461732 PMCID: PMC3127012 DOI: 10.1007/s00259-011-1806-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 03/15/2011] [Indexed: 10/25/2022]
Abstract
PURPOSE Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide therapy. Several CCK-2 receptor-binding radiopeptides have been developed and some have been tested in patients. Here we aimed to compare the in vivo tumour targeting properties of 12 (111)In-labelled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated gastrin/CCK2 receptor-binding peptides. METHODS Two CCK8-based peptides and ten gastrin-based peptide analogues were tested. All peptides were conjugated with DOTA and labelled with (111)In. Biodistribution studies were performed in mice with subcutaneous CCK2/gastrin receptor-expressing tumours and with receptor-negative tumours contralaterally. Biodistribution was studied by counting dissected tissues at 1 and 4 h after injection. RESULTS Both the CCK analogues displayed relatively low tumour uptake (approximately 2.5%ID/g) as compared to minigastrin analogues. Two linear minigastrin peptides (MG0 and sargastrin) displayed moderate tumour uptake at both 1 and 4 h after injection, but also very high kidney uptake (both higher than 48%ID/g). The linear MG11, lacking the penta-Glu sequence, showed lower tumour uptake and also low kidney uptake. Varying the N-terminal Glu residues in the minigastrin analogues led to improved tumour targeting properties, with PP-F11 displaying the optimal biodistribution. Besides the monomeric linear peptides, a cyclized peptide and a divalent peptide were tested. CONCLUSION Based on these studies, optimal peptides for peptide receptor radionuclide targeting of CCK2/gastrin receptor-expressing tumours were the linear minigastrin analogue with six D-Glu residues (PP-F11), the divalent analogue MGD5 and the cyclic peptide cyclo-MG1. These peptides combined high tumour uptake with low kidney retention, and may therefore be good candidates for future clinical studies.
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Kolenc-Peitl P, Mansi R, Tamma M, Gmeiner-Stopar T, Sollner-Dolenc M, Waser B, Baum RP, Reubi JC, Maecke HR. Highly improved metabolic stability and pharmacokinetics of indium-111-DOTA-gastrin conjugates for targeting of the gastrin receptor. J Med Chem 2011; 54:2602-9. [PMID: 21456601 DOI: 10.1021/jm101279a] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The development of metabolically stable radiolabeled gastrin analogues with suitable pharmacokinetics is a topic of recent research activity. These imaging vectors are of interest because the gastrin/CCK2 receptor is highly overexpressed in different tumors such as medullary thyroid cancer, neuroendocrine tumors, and SCLC. The drawback of current targeting agents is either their metabolic instability or their high kidney uptake. We present the synthesis and in vitro and in vivo evaluation of 11 (111)In-labeled DOTA-conjugated peptides that differ by their spacer between the peptide and the chelate. We introduced uncharged but hydrophilic spacers such as oligoethyleneglycol, serine, and glutamine. The affinity of all radiopeptides was high with IC(50) values between 0.5 and 4.8 nM. The improvement of human serum stability is 500-fold within this series of compounds. In addition the kidney uptake could be lowered distinctly and the tumor-to-kidney ratio improved almost 60-fold if compared with radiotracers having charged spacers such as glutamic acid.
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Affiliation(s)
- Petra Kolenc-Peitl
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia
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Correia JDG, Paulo A, Raposinho PD, Santos I. Radiometallated peptides for molecular imaging and targeted therapy. Dalton Trans 2011; 40:6144-67. [DOI: 10.1039/c0dt01599g] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pool SE, Krenning EP, Koning GA, van Eijck CHJ, Teunissen JJM, Kam B, Valkema R, Kwekkeboom DJ, de Jong M. Preclinical and clinical studies of peptide receptor radionuclide therapy. Semin Nucl Med 2010; 40:209-18. [PMID: 20350630 DOI: 10.1053/j.semnuclmed.2009.12.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the 1980s, the (111)In-labeled somatostatin analog OctreoScan (Covidien, Hazelwood, MO) was developed for imaging of somatostatin receptor subtype 2 (sst(2)) overexpressing tumors. On the basis of this success, peptide receptor radionuclide therapy (PRRT) was developed using similar somatostatin analogs with different therapeutic radionuclides. Clinical application of PRRT demonstrated impressive results on tumor response, overall survival, and quality of life in patients with gastroenteropancreatic neuroendocrine tumors. The peptides 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), Tyr(3)-octreotate (DOTATATE) and DOTA, Tyr(3)-octreotide (DOTATOC) (brand name Onalta), predominantly targeting sst(2), have been granted Orphan Drug status by the European Medicines Agency and the US Food and Drug Administration for application in PRRT. Besides somatostatin receptor-targeting peptides, multiple other radiopeptide analogs were developed targeting several other receptors overexpressed on various tumors. Some of these peptide analogs, including cholecystokinin, gastrin, gastrin-releasing peptide, arginine-glycine-aspartate (RGD)-peptides, and glucagon-like peptide 1 analogs appeared very promising in preclinical and clinical imaging and PRRT studies. Although the success of PRRT with radiolabeled somatostatin analogs has been established, there is still room for improvement. The therapeutic window of PRRT could be enlarged by the use of new and improved targeting compounds, of which new antagonists with excellent tumor to background ratios are very promising. Furthermore, locoregional administration, improved healthy tissue protection, and combination treatment can be applied to increase the effectiveness of PRRT. Combination treatment might include cocktails of different peptide analogs of different therapeutic radionuclides and of radiolabeled peptides with chemotherapeutic or radiosensitizing agents. This review summarizes results of PRRT and describes clinical and preclinical studies regarding PRRT optimizing strategies.
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Affiliation(s)
- Stefan E Pool
- Department of Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
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Bartholomä MD, Louie AS, Valliant JF, Zubieta J. Technetium and Gallium Derived Radiopharmaceuticals: Comparing and Contrasting the Chemistry of Two Important Radiometals for the Molecular Imaging Era. Chem Rev 2010; 110:2903-20. [DOI: 10.1021/cr1000755] [Citation(s) in RCA: 250] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Mark D. Bartholomä
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, and Department of Chemistry, McMaster University, Hamilton, Canada ON L8S 4M1
| | - Anika S. Louie
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, and Department of Chemistry, McMaster University, Hamilton, Canada ON L8S 4M1
| | - John F. Valliant
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, and Department of Chemistry, McMaster University, Hamilton, Canada ON L8S 4M1
| | - Jon Zubieta
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, and Department of Chemistry, McMaster University, Hamilton, Canada ON L8S 4M1
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Roosenburg S, Laverman P, van Delft FL, Boerman OC. Radiolabeled CCK/gastrin peptides for imaging and therapy of CCK2 receptor-expressing tumors. Amino Acids 2010; 41:1049-58. [PMID: 20198494 PMCID: PMC3205271 DOI: 10.1007/s00726-010-0501-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 01/25/2010] [Indexed: 11/30/2022]
Abstract
Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, like medullary thyroid carcinomas, small cell lung cancers and stromal ovarian cancers. The specific receptor-binding property of the endogenous ligands for these receptors can be exploited by labeling peptides with a radionuclide and using these as carriers to guide the radioactivity to the tissues that express the receptors. In this way, tumors can be visualized using positron emission tomography and single photon emission computed tomography imaging. A variety of radiolabeled CCK/gastrin-related peptides has been synthesized and characterized for imaging. All peptides have the C-terminal CCK receptor-binding tetrapeptide sequence Trp-Met-Asp-Phe-NH2 in common or derivatives thereof. This review focuses on the development and application of radiolabeled CCK/gastrin peptides for radionuclide imaging and radionuclide therapy of tumors expressing CCK receptors. We discuss both preclinical studies as well as clinical studies with CCK and gastrin peptides.
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Affiliation(s)
- Susan Roosenburg
- Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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