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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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Holzleitner N, Günther T, Daoud-Gadieh A, Lapa C, Wester HJ. Investigation of the structure-activity relationship at the N-terminal part of minigastrin analogs. EJNMMI Res 2023; 13:65. [PMID: 37421545 DOI: 10.1186/s13550-023-01016-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/29/2023] [Indexed: 07/10/2023] Open
Abstract
BACKGROUND Over the last years, several strategies have been reported to improve the metabolic stability of minigastrin analogs. However, currently applied compounds still reveal limited in vitro and in vivo stability. We thus performed a glycine scan at the N-terminus of DOTA-MGS5 (DOTA-D-Glu-Ala-Tyr-Gly-Trp-(N-Me)Nle-Asp-1-Nal) to systematically analyze the peptide structure. We substituted N-terminal amino acids by simple PEG spacers and investigated in vitro stability in human serum. Furthermore, we evaluated different modifications on its tetrapeptide binding sequence (H-Trp-(N-Me)Nle-Asp-1-Nal-NH2). RESULTS Affinity data of all glycine scan peptides were found to be in a low nanomolar range (4.2-8.5 nM). However, a truncated compound lacking the D-γ-Glu-Ala-Tyr sequence revealed a significant loss in CCK-2R affinity. Substitution of the D-γ-Glu-Ala-Tyr-Gly sequence of DOTA-γ-MGS5 (DOTA- D-γ-Glu-Ala-Tyr-Gly-Trp-(N-Me)Nle-Asp-1-Nal-NH2) by polyethylene glycol (PEG) spacers of different length exhibited only a minor influence on CCK-2R affinity and lipophilicity. However, in vitro stability of the PEG-containing compounds was significantly decreased. In addition, we confirmed that the tetrapeptide sequence H-Trp-Asp-(N-Me)Nle-1-Nal-NH2 is indeed sufficient for high CCK-2R affinity. CONCLUSION We could demonstrate that a substitution of D-γ-Glu-Ala-Tyr-Gly by PEG spacers simplified the peptide structure of DOTA-MGS5 while high CCK-2R affinity and favorable lipophilicity were maintained. Nevertheless, further optimization with regard to metabolic stability must be carried out for these minigastrin analogs.
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Affiliation(s)
- Nadine Holzleitner
- Department of Chemistry, Technical University of Munich, 85748, Garching, Germany
| | - Thomas Günther
- Department of Chemistry, Technical University of Munich, 85748, Garching, Germany.
| | - Amira Daoud-Gadieh
- Department of Chemistry, Technical University of Munich, 85748, Garching, Germany
| | - Constantin Lapa
- Nuclear Medicine, University Hospital Augsburg, 86156, Augsburg, Germany
| | - Hans-Jürgen Wester
- Department of Chemistry, Technical University of Munich, 85748, Garching, Germany
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[ 111In]In-CP04 as a novel cholecystokinin-2 receptor ligand with theranostic potential in patients with progressive or metastatic medullary thyroid cancer: final results of a GRAN-T-MTC Phase I clinical trial. Eur J Nucl Med Mol Imaging 2023; 50:892-907. [PMID: 36334104 PMCID: PMC9852173 DOI: 10.1007/s00259-022-05992-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Medullary thyroid cancer (MTC) is a rare malignant tumour of the parafollicular C-cells with an unpredictable clinical course and currently suboptimal diagnostic and therapeutic options, in particular in advanced disease. Overexpression of cholecystokinin-2 receptors (CCK2R) represents a promising avenue to diagnostic imaging and targeted therapy, ideally through a theranostic approach. MATERIALS AND METHODS A translational study (GRAN-T-MTC) conducted through a Phase I multicentre clinical trial of the indium-111 labelled CP04 ([111In]In-CP04), a CCK2R-seeking ligand was initiated with the goal of developing a theranostic compound. Patients with proven advanced/metastatic MTC or short calcitonin doubling time were enrolled. A two-step concept was developed through the use of low- and high-peptide mass (10 and 50 μg, respectively) for safety assessment, with the higher peptide mass considered appropriate for therapeutic application. Gelofusine was co-infused in a randomized fashion in the second step for the evaluation of potential reduction of the absorbed dose to the kidneys. Imaging for the purpose of biodistribution, dosimetry evaluation, and diagnostic assessment were performed as well as pre-, peri-, and postprocedural clinical and biochemical assessment. RESULTS Sixteen patients were enrolled. No serious adverse events after application of the compound at both peptide amounts were witnessed; transient tachycardia and flushing were observed in two patients. No changes in biochemistry and clinical status were observed on follow-up. Preliminary dosimetry assessment revealed the highest dose to urinary bladder, followed by the kidneys and stomach wall. The effective dose for 200 MBq of [111In]In-CP04 was estimated at 7±3 mSv and 7±1 mSv for 10 μg and 50 μg CP04, respectively. Administration of Gelofusine reduced the dose to the kidneys by 53%, resulting in the organ absorbed dose of 0.044±0.019 mSv/MBq. Projected absorbed dose to the kidneys with the use of [177Lu]Lu-CP04 was estimated at 0.9±0.4 Gy/7.4 GBq. [111In]In-CP04 scintigraphy was positive in 13 patients (detection rate of 81%) with superior diagnostic performance over conventional imaging. CONCLUSION In the present study, [111In]In-CP04 was shown to be a safe and effective radiopharmaceutical with promising theranostic characteristics for patients with advanced MTC.
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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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Radiopharmaceutical Formulation and Preclinical Testing of 68Ga-Labeled DOTA-MGS5 for the Regulatory Approval of a First Exploratory Clinical Trial. Pharmaceuticals (Basel) 2021; 14:ph14060575. [PMID: 34208516 PMCID: PMC8235783 DOI: 10.3390/ph14060575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 12/15/2022] Open
Abstract
The new minigastrin analog DOTA-MGS5 is a promising new candidate for targeting cholecystokinin-2 receptor (CCK2R)-expressing tumors. To enable the clinical translation of PET/CT imaging using 68Ga-labeled DOTA-MGS5, different quality and safety aspects need to be considered to comply with the regulatory framework for clinical trial application. The preparation of the radiopharmaceutical was established using a cassette-based automated synthesis unit. Product specifications, including analytical procedures and acceptance criteria, were adopted from Ph. Eur. monographs for other 68Ga-labeled radiopharmaceuticals. Non-clinical studies included receptor affinity and cell uptake studies using two different CCK2R-expressing cell lines, as well as pharmacokinetic biodistribution studies in BALB/c mice for dosimetry calculations and toxicological studies in Wistar rats. The produced masterbatches fulfilled the defined acceptance criteria. DOTA-MGS5, with confirmed affinity to the CCK2R, showed a high specific cell uptake and no interaction with other receptors in vitro when radiolabeled with gallium-68. Favorable in vivo properties were observed in biodistribution and dosimetry studies. An effective dose of ~0.01 mSv/MBq was estimated for humans utilizing OLINDA/EXM software. A maximum peptide dose of 50 µg was established for the initial clinical dose based on the toxicity study in rats. The standardized production of [68Ga]Ga-DOTA-MGS5 using an automated synthesis module and the performed non-clinical safety studies support a first exploratory clinical trial with this new PET imaging agent.
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Improved Tumor-Targeting with Peptidomimetic Analogs of Minigastrin 177Lu-PP-F11N. Cancers (Basel) 2021; 13:cancers13112629. [PMID: 34071914 PMCID: PMC8199036 DOI: 10.3390/cancers13112629] [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: 04/23/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Several radiolabeled peptides targeting CCK2R-positive types of cancer (such as medullary thyroid cancer and small cell lung cancer) have been reported in the last 25 years, some of which have entered clinical trials. In an effort to improve its tumor-targeting properties, we applied chemical modifications to the backbone of the peptide 177Lu-PP-F11N, an analog of minigastrin in clinical trials. The generated radiolabeled peptidomimetics showed significantly improved characteristics in mice bearing CCK2R-positive tumor xenografts, such as higher tumor uptake, slower tumor washout, and increased tumor-to-kidney ratios. These properties make the novel compounds promising candidates for the imaging and therapy of CCK2R-positive tumors and metastases. Abstract The cholecystokinin-2 receptor (CCK2R) is an attractive target in nuclear medicine due to its overexpression by different tumors. Several radiolabeled peptidic ligands targeting the CCK2R have been investigated in the past; however, their low stability against proteases can limit their uptake in tumors and metastases. Substitution of single or multiple amide bonds with metabolically stable 1,4-disubstituted 1,2,3-triazoles as amide bond bioisosteres proved a promising strategy for improving the tumor-targeting properties of a truncated analog of minigastrin. In this study, we applied the previously studied structural modifications to improve the pharmacokinetic and pharmacodynamic properties of PP-F11N, a minigastrin analog currently in clinical trials. Novel minigastrins (NMGs) as analogs of PP-F11N with one or two amide bonds substituted by 1,2,3-triazoles were synthesized, radiolabeled with 177Lu3+, and subjected to full evaluation in vitro (cell internalization, receptor affinity, stability in blood plasma) and in vivo (stability, biodistribution, SPECT/CT imaging). NMGs with triazoles inserted between the amino acids DGlu10-Ala11 and/or Tyr12-Gly13 showed a significantly increased cellular uptake and affinity toward the CCK2R in vitro. Resistance against the metabolic degradation of the NMGs was comparable to those of the clinical candidate PP-F11N. Imaging by SPECT/CT and biodistribution studies demonstrated a higher uptake in CCK2R-positive tumors but also in the CCK2R-positive stomach. The peptidomimetic compounds showed a slow tumor washout and high tumor-to-kidney ratios. The structural modifications led to the identification of analogs with promising properties for progression to clinical applications in the diagnosis and therapy of CCK2R-positive neoplasms.
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Corlett A, Sani MA, Van Zuylekom J, Ang CS, von Guggenberg E, Cullinane C, Blyth B, Hicks RJ, Roselt PD, Thompson PE, Hutton CA, Haskali MB. A New Turn in Peptide-Based Imaging Agents: Foldamers Afford Improved Theranostics Targeting Cholecystokinin-2 Receptor-Positive Cancer. J Med Chem 2021; 64:4841-4856. [PMID: 33826325 DOI: 10.1021/acs.jmedchem.0c02213] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Proteins adopt unique folded secondary and tertiary structures that are responsible for their remarkable biological properties. This structural complexity is key in designing efficacious peptides that can mimic the three-dimensional structure needed for biological function. In this study, we employ different chemical strategies to induce and stabilize a β-hairpin fold of peptides targeting cholecystokinin-2 receptors for theranostic application (combination of a targeted therapeutic and a diagnostic companion). The newly developed peptides exhibited enhanced folding capacity as demonstrated by circular dichroism (CD) spectroscopy, ion-mobility spectrometry-mass spectrometry, and two-dimensional (2D) NMR experiments. Enhanced folding characteristics of the peptides led to increased biological potency, affording four optimal Ga-68 labeled radiotracers ([68Ga]Ga-4b, [68Ga]Ga-11b-13b) targeting CCK-2R. In particular, [68Ga]Ga-12b and [68Ga]Ga-13b presented improved metabolic stability, enhanced cell internalization, and up to 6 fold increase in tumor uptake. These peptides hold great promise as next-generation theranostic radiopharmaceuticals.
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Affiliation(s)
- Alicia Corlett
- Department of Nuclear Medicine, The Royal Melbourne Hospital, Melbourne, VIC 3000, Australia
| | | | - Jessica Van Zuylekom
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia
| | - Ching-Seng Ang
- The Mass Spectrometry and Proteomics Facility, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville 3010, Australia
| | | | - Carleen Cullinane
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Benjamin Blyth
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Rodney J Hicks
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Peter D Roselt
- The Radiopharmaceutical Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia
| | - Philip E Thompson
- Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University (Parkville Campus), Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville VIC 3052, Australia
| | | | - Mohammad B Haskali
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC 3010, Australia.,The Radiopharmaceutical Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia
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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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Hörmann AA, Klingler M, Rezaeianpour M, Hörmann N, Gust R, Shahhosseini S, von Guggenberg E. Initial In Vitro and In Vivo Evaluation of a Novel CCK2R Targeting Peptide Analog Labeled with Lutetium-177. Molecules 2020; 25:molecules25194585. [PMID: 33049999 PMCID: PMC7583830 DOI: 10.3390/molecules25194585] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/25/2020] [Accepted: 10/01/2020] [Indexed: 02/06/2023] Open
Abstract
Targeting of cholecystokinin-2 receptor (CCK2R) expressing tumors using radiolabeled minigastrin (MG) analogs is hampered by rapid digestion of the linear peptide in vivo. In this study, a new MG analog stabilized against enzymatic degradation was investigated in preclinical studies to characterize the metabolites formed in vivo. The new MG analog DOTA-DGlu-Pro-Tyr-Gly-Trp-(N-Me)Nle-Asp-1Nal-NH2 comprising site-specific amino acid substitutions in position 2, 6 and 8 and different possible metabolites thereof were synthesized. The receptor interaction of the peptide and selected metabolites was evaluated in a CCK2R-expressing cell line. The enzymatic stability of the 177Lu-labeled peptide analog was evaluated in vitro in different media as well as in BALB/c mice up to 1 h after injection and the metabolites were identified based on radio-HPLC analysis. The new radiopeptide showed a highly increased stability in vivo with >56% intact radiopeptide in the blood of BALB/c mice 1 h after injection. High CCK2R affinity and cell uptake was confirmed only for the intact peptide, whereas enzymatic cleavage within the receptor specific C-terminal amino acid sequence resulted in complete loss of affinity and cell uptake. A favorable biodistribution profile was observed in BALB/c mice with low background activity, preferential renal excretion and prolonged uptake in CCK2R-expressing tissues. The novel stabilized MG analog shows high potential for diagnostic and therapeutic use. The radiometabolites characterized give new insights into the enzymatic degradation in vivo.
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Affiliation(s)
- Anton Amadeus Hörmann
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (A.A.H.); (M.K.); (M.R.)
| | - Maximilian Klingler
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (A.A.H.); (M.K.); (M.R.)
| | - Maliheh Rezaeianpour
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (A.A.H.); (M.K.); (M.R.)
- Pharmaceutical Chemistry and Radiopharmacy Department, School of Pharmacy, Shahid Beheshti University of Medical Sciences, 1991953381 Tehran, Iran;
| | - Nikolas Hörmann
- Department of Pharmaceutical Chemistry, University of Innsbruck, 6020 Innsbruck, Austria; (N.H.); (R.G.)
| | - Ronald Gust
- Department of Pharmaceutical Chemistry, University of Innsbruck, 6020 Innsbruck, Austria; (N.H.); (R.G.)
| | - Soraya Shahhosseini
- Pharmaceutical Chemistry and Radiopharmacy Department, School of Pharmacy, Shahid Beheshti University of Medical Sciences, 1991953381 Tehran, Iran;
| | - Elisabeth von Guggenberg
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (A.A.H.); (M.K.); (M.R.)
- Correspondence: ; Tel.: +43-512-504-80960
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Mohtavinejad N, Shafiee Ardestani M, Khalaj A, Pormohammad A, Najafi R, Bitarafan-Rajabi A, Hajiramezanali M, Amanlou M. Application of radiolabeled peptides in tumor imaging and therapy. Life Sci 2020; 258:118206. [PMID: 32758623 DOI: 10.1016/j.lfs.2020.118206] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/24/2020] [Accepted: 08/01/2020] [Indexed: 12/18/2022]
Abstract
Scientists are looking for new therapies to cope with the rise in cancer worldwide. Since cancer cells overexpress peptide receptors and owing to small size, easy uptake by tumor cells, easy preparation, and with no toxicity, the use of radiolabeled peptides with high specificity and affinity for accurate imaging and therapy has attracted much attention. To develop an ideal imaging or treatment radiolabeled peptide, there are some aspects in the components of radiolabeled peptide including radionuclide, peptide, chelator, and spacer that should be considered. Some peptides, including somatostatin, RGD, neurotensin, bombesin, exendin, vasoactive intestinal peptide, and gastrin are currently under (pre)clinical investigations. Today, nanoparticles are suitable tools for targeting peptide for molecular imaging and therapy of tumors with low toxicity. This paper presents some essential aspects in developing a valuable radiolabeled peptide and some radiolabeled peptides with regard to their applications in tumor imaging and therapy in pre-clinical and clinical phases.
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Affiliation(s)
- Naser Mohtavinejad
- Department of Radiopharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Shafiee Ardestani
- Department of Radiopharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
| | - Ali Khalaj
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Pormohammad
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Reza Najafi
- Department of Radioisotope, Nuclear Research Center, AOEI, Tehran, Iran
| | - Ahmad Bitarafan-Rajabi
- Echocardiography Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Cardiovascular Interventional Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Maliheh Hajiramezanali
- Department of Radiopharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Massoud Amanlou
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
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Evans BJ, King AT, Katsifis A, Matesic L, Jamie JF. Methods to Enhance the Metabolic Stability of Peptide-Based PET Radiopharmaceuticals. Molecules 2020; 25:molecules25102314. [PMID: 32423178 PMCID: PMC7287708 DOI: 10.3390/molecules25102314] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/28/2022] Open
Abstract
The high affinity and specificity of peptides towards biological targets, in addition to their favorable pharmacological properties, has encouraged the development of many peptide-based pharmaceuticals, including peptide-based positron emission tomography (PET) radiopharmaceuticals. However, the poor in vivo stability of unmodified peptides against proteolysis is a major challenge that must be overcome, as it can result in an impractically short in vivo biological half-life and a subsequently poor bioavailability when used in imaging and therapeutic applications. Consequently, many biologically and pharmacologically interesting peptide-based drugs may never see application. A potential way to overcome this is using peptide analogues designed to mimic the pharmacophore of a native peptide while also containing unnatural modifications that act to maintain or improve the pharmacological properties. This review explores strategies that have been developed to increase the metabolic stability of peptide-based pharmaceuticals. It includes modifications of the C- and/or N-termini, introduction of d- or other unnatural amino acids, backbone modification, PEGylation and alkyl chain incorporation, cyclization and peptide bond substitution, and where those strategies have been, or could be, applied to PET peptide-based radiopharmaceuticals.
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Affiliation(s)
- Brendan J. Evans
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia; (B.J.E.); (A.T.K.)
| | - Andrew T. King
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia; (B.J.E.); (A.T.K.)
| | - Andrew Katsifis
- Department of Molecular Imaging, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia;
| | - Lidia Matesic
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia;
| | - Joanne F. Jamie
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia; (B.J.E.); (A.T.K.)
- Correspondence: ; Tel.: +61-2-9850-8283
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Ritler A, Shoshan MS, Deupi X, Wilhelm P, Schibli R, Wennemers H, Béhé M. Elucidating the Structure-Activity Relationship of the Pentaglutamic Acid Sequence of Minigastrin with Cholecystokinin Receptor Subtype 2. Bioconjug Chem 2019; 30:657-666. [PMID: 30608664 DOI: 10.1021/acs.bioconjchem.8b00849] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Derivatized minigastrin analogues make up a promising class of candidates for targeting cholecystokinin receptor subtype 2 (CCK2R), which is overexpressed on cancer cells of various neuroendocrine tumors. The pentaglutamic acid sequence of minigastrin influences its biological properties. In particular, it plays a crucial role in the kidney reuptake mechanism. However, the importance of the binding affinity and interaction of this region with the receptor on a molecular level remains unclear. To elucidate its structure-activity relationship with CCK2R, we replaced this sequence with various linkers differing in their amount of anionic charge, structural characteristics, and flexibility. Specifically, a flexible aliphatic linker, a linker with only three d-Glu residues, and a structured linker with four adjacent β3-glutamic acid residues were evaluated and compared to the lead compound PP-F11N (DOTA-[d-Glu1-6,Nle11]gastrin-13). 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was conjugated to the minigastrin derivatives, which allowed radiolabeling with Lutetium-177. The levels of In vitro internalization into MZ-CRC1 cells and in vivo tumor uptake as well as human blood plasma stability increased in the following order: aliphatic linker < three d-Glu < (β3-Glu)4 < (d-Glu)6. The in vitro and in vivo behavior was therefore significantly improved with anionic charges. Computational modeling of a CCK2 receptor-ligand complex revealed ionic interactions between cationic residues (Arg and His) of the receptor and anionic residues of the ligand in the linker.
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Affiliation(s)
- Andreas Ritler
- Department of Chemistry and Applied Biosciences (D-CHAB), Laboratory of Organic Chemistry (LOC) , ETH , CH-8093 Zurich , Switzerland.,Department of Chemistry and Applied Biosciences (D-CHAB), Institute of Pharmaceutical Sciences (IPW) , ETH , CH-8093 Zurich , Switzerland.,Research Department of Biology and Chemistry, Center for Radiopharmaceutical Sciences (CRS) , Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | - Michal S Shoshan
- Department of Chemistry and Applied Biosciences (D-CHAB), Laboratory of Organic Chemistry (LOC) , ETH , CH-8093 Zurich , Switzerland
| | - Xavier Deupi
- Laboratory of Biomolecular Research and Condensed Matter Theory Group , Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | - Patrick Wilhelm
- Department of Chemistry and Applied Biosciences (D-CHAB), Laboratory of Organic Chemistry (LOC) , ETH , CH-8093 Zurich , Switzerland
| | - Roger Schibli
- Department of Chemistry and Applied Biosciences (D-CHAB), Institute of Pharmaceutical Sciences (IPW) , ETH , CH-8093 Zurich , Switzerland.,Research Department of Biology and Chemistry, Center for Radiopharmaceutical Sciences (CRS) , Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | - Helma Wennemers
- Department of Chemistry and Applied Biosciences (D-CHAB), Laboratory of Organic Chemistry (LOC) , ETH , CH-8093 Zurich , Switzerland
| | - Martin Béhé
- Research Department of Biology and Chemistry, Center for Radiopharmaceutical Sciences (CRS) , Paul Scherrer Institute , CH-5232 Villigen , Switzerland
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14
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Erba PA, Maecke H, Mikolajczak R, Decristoforo C, Zaletel K, Maina-Nock T, Peitl PK, Garnuszek P, Froberg A, Goebel G, de Jong M, Jabrocka-Hybel A, Konijnenberg M, Virgolini I, Nock B, Lenda-Tracz W, Pawlak D, Rangger C, Trofimiuk-Müldner M, Sowa-Staszczak A, Tomaszuk M, von Guggenberg E, Scarpa L, Hubalewska-Dydejczyk A. A novel CCK2/gastrin receptor-localizing radiolabeled peptide probe for personalized diagnosis and therapy of patients with progressive or metastatic medullary thyroid carcinoma: a multicenter phase I GRAN-T-MTC study. Pol Arch Intern Med 2018; 128:791-795. [PMID: 30516761 PMCID: PMC6347971 DOI: 10.20452/pamw.4387] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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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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16
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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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New Insights in the Design of Bioactive Peptides and Chelating Agents for Imaging and Therapy in Oncology. Molecules 2017; 22:molecules22081282. [PMID: 28767081 PMCID: PMC6152110 DOI: 10.3390/molecules22081282] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/25/2017] [Indexed: 11/16/2022] Open
Abstract
Many synthetic peptides have been developed for diagnosis and therapy of human cancers based on their ability to target specific receptors on cancer cell surface or to penetrate the cell membrane. Chemical modifications of amino acid chains have significantly improved the biological activity, the stability and efficacy of peptide analogues currently employed as anticancer drugs or as molecular imaging tracers. The stability of somatostatin, integrins and bombesin analogues in the human body have been significantly increased by cyclization and/or insertion of non-natural amino acids in the peptide sequences. Moreover, the overall pharmacokinetic properties of such analogues and others (including cholecystokinin, vasoactive intestinal peptide and neurotensin analogues) have been improved by PEGylation and glycosylation. Furthermore, conjugation of those peptide analogues to new linkers and bifunctional chelators (such as AAZTA, TETA, TRAP, NOPO etc.), produced radiolabeled moieties with increased half life and higher binding affinity to the cognate receptors. This review describes the most important and recent chemical modifications introduced in the amino acid sequences as well as linkers and new bifunctional chelators which have significantly improved the specificity and sensitivity of peptides used in oncologic diagnosis and therapy.
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18
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Fani M, Peitl PK, Velikyan I. Current Status of Radiopharmaceuticals for the Theranostics of Neuroendocrine Neoplasms. Pharmaceuticals (Basel) 2017; 10:E30. [PMID: 28295000 PMCID: PMC5374434 DOI: 10.3390/ph10010030] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 02/06/2023] Open
Abstract
Nuclear medicine plays a pivotal role in the management of patients affected by neuroendocrine neoplasms (NENs). Radiolabeled somatostatin receptor analogs are by far the most advanced radiopharmaceuticals for diagnosis and therapy (radiotheranostics) of NENs. Their clinical success emerged receptor-targeted radiolabeled peptides as an important class of radiopharmaceuticals and it paved the way for the investigation of other radioligand-receptor systems. Besides the somatostatin receptors (sstr), other receptors have also been linked to NENs and quite a number of potential radiolabeled peptides have been derived from them. The Glucagon-Like Peptide-1 Receptor (GLP-1R) is highly expressed in benign insulinomas, the Cholecystokinin 2 (CCK2)/Gastrin receptor is expressed in different NENs, in particular medullary thyroid cancer, and the Glucose-dependent Insulinotropic Polypeptide (GIP) receptor was found to be expressed in gastrointestinal and bronchial NENs, where interestingly, it is present in most of the sstr-negative and GLP-1R-negative NENs. Also in the field of sstr targeting new discoveries brought into light an alternative approach with the use of radiolabeled somatostatin receptor antagonists, instead of the clinically used agonists. The purpose of this review is to present the current status and the most innovative strategies for the diagnosis and treatment (theranostics) of neuroendocrine neoplasms using a cadre of radiolabeled regulatory peptides targeting their receptors.
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Affiliation(s)
- Melpomeni Fani
- Division of Radiopharmaceutical Chemistry, University Hospital of Basel, 4031 Basel, Switzerland.
| | - Petra Kolenc Peitl
- Department of Nuclear Medicine, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia.
| | - Irina Velikyan
- Department of Medicinal Chemistry, Uppsala University, 751 23 Uppsala, Sweden.
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Kaloudi A, Nock BA, Lymperis E, Krenning EP, de Jong M, Maina T. Improving the In Vivo Profile of Minigastrin Radiotracers: A Comparative Study Involving the Neutral Endopeptidase Inhibitor Phosphoramidon. Cancer Biother Radiopharm 2016; 31:20-8. [PMID: 26844849 DOI: 10.1089/cbr.2015.1935] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Minigastrin radiotracers, such as [(111)In-DOTA]MG0 ([(111)In-DOTA-DGlu(1)]minigastrin), have been considered for diagnostic imaging and radionuclide therapy of CCK2R-positive human tumors, such as medullary thyroid carcinoma. However, the high kidney retention assigned to the pentaGlu(2-6) repeat in the peptide sequence has compromised their clinical applicability. On the other hand, truncated des(Glu)(2-6)-analogs, such as [(111)In-DOTA]MG11 ([(111)In-DOTA-DGlu(10),desGlu(2-6)]minigastrin), despite their low renal uptake, show poor bioavailability and tumor targeting. [(111)In]CP04 ([(111)In-DOTA-DGlu(1-6)]minigastrin) acquired by Glu(2-6)/DGlu(2-6) substitution showed promising tumor-to-kidney ratios in rodents. In the present study, we compare the biological profiles of [(111)In]CP04, [(111)In-DOTA]MG11, and [(111)In-DOTA]MG0 during in situ neutral endopeptidase (NEP) inhibition, recently shown to improve the bioavailability of several peptide radiotracers. After coinjection of the NEP inhibitor, phosphoramidon (PA), the stability of [(111)In]CP04 and [(111)In-DOTA]MG0 in peripheral mouse blood increased, with an exceptional >14-fold improvement monitored for [(111)In-DOTA]MG11. In line with these findings, PA treatment increased the uptake of [(111)In]CP04 (8.5 ± 0.4%ID/g to 16.0 ± 2.3%ID/g) and [(111)In-DOTA]MG0 (11.9 ± 2.2%ID/g to 17.2 ± 0.9%ID/g) in A431-CCK2R(+) tumors at 4 hours postinjection, whereas the respective increase for [(111)In-DOTA]MG11 was >6-fold (2.5 ± 0.9%ID/g to 15.1 ± 1.7%ID/g). Interestingly, kidney uptake remained lowest for [(111)In-DOTA]MG11, but unfavorably increased by PA treatment for [(111)In-DOTA]MG0. Thus, overall, the most favorable in vivo profile was displayed by [(111)In-DOTA]MG11 during NEP inhibition, highlighting the need to validate this promising concept in the clinic.
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Affiliation(s)
- Aikaterini Kaloudi
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Berthold A Nock
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Emmanouil Lymperis
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Eric P Krenning
- 2 Department of Nuclear Medicine, Erasmus MC , Rotterdam, The Netherlands
| | - Marion de Jong
- 2 Department of Nuclear Medicine, Erasmus MC , Rotterdam, The Netherlands .,3 Department of Radiology, Erasmus MC , Rotterdam, The Netherlands
| | - Theodosia Maina
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
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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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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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