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Kanellopoulos P, Nock BA, Rouchota M, Loudos G, Krenning EP, Maina T. Side-Chain Modified [ 99mTc]Tc-DT1 Mimics: A Comparative Study in NTS 1R-Positive Models. Int J Mol Sci 2023; 24:15541. [PMID: 37958525 PMCID: PMC10647616 DOI: 10.3390/ijms242115541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Radiolabeled neurotensin analogs have been developed as candidates for theranostic use against neurotensin subtype 1 receptor (NTS1R)-expressing cancer. However, their fast degradation by two major peptidases, neprilysin (NEP) and angiotensin-converting enzyme (ACE), has hitherto limited clinical success. We have recently shown that palmitoylation at the ε-amine of Lys7 in [99mTc]Tc-[Lys7]DT1 (DT1, N4-Gly-Arg-Arg-Pro-Tyr-Ile-Leu-OH, N4 = 6-(carboxy)-1,4,8,11-tetraazaundecane) led to the fully stabilized [99mTc]Tc-DT9 analog, displaying high uptake in human pancreatic cancer AsPC-1 xenografts but unfavorable pharmacokinetics in mice. Aiming to improve the in vivo stability of [99mTc]Tc-DT1 without compromising pharmacokinetics, we now introduce three new [99mTc]Tc-DT1 mimics, carrying different pendant groups at the ε-amine of Lys7: MPBA (4-(4-methylphenyl)butyric acid)-[99mTc]Tc-DT10; MPBA via a PEG4-linker-[99mTc]Tc-DT11; or a hydrophilic PEG6 chain-[99mTc]Tc-DT12. The impact of these modifications on receptor affinity and internalization was studied in NTS1R-positive cells. The effects on stability and AsPC-1 tumor uptake were assessed in mice without or during NEP/ACE inhibition. Unlike [99mTc]Tc-DT10, the longer-chain modified [99mTc]Tc-DT11 and [99mTc]Tc-DT12 were significantly stabilized in vivo, resulting in markedly improved tumor uptake compared to [99mTc]Tc-DT1. [99mTc]Tc-DT11 was found to achieve the highest AsPC-1 tumor values and good pharmacokinetics, either without or during NEP inhibition, qualifying for further validation in patients with NTS1R-positive tumors using SPECT/CT.
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Affiliation(s)
| | - Berthold A. Nock
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (B.A.N.)
| | - Maritina Rouchota
- BIOEMTECH, Lefkippos Attica Technology Park NCSR “Demokritos”, 15310 Athens, Greece; (M.R.); (G.L.)
| | - George Loudos
- BIOEMTECH, Lefkippos Attica Technology Park NCSR “Demokritos”, 15310 Athens, Greece; (M.R.); (G.L.)
| | - Eric P. Krenning
- Cyclotron Rotterdam BV, Erasmus MC, 3015 CE Rotterdam, The Netherlands;
| | - Theodosia Maina
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (B.A.N.)
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2
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Kanellopoulos P, Nock BA, Krenning EP, Maina T. Toward Stability Enhancement of NTS 1R-Targeted Radioligands: Structural Interventions on [ 99mTc]Tc-DT1. Pharmaceutics 2023; 15:2092. [PMID: 37631306 PMCID: PMC10459693 DOI: 10.3390/pharmaceutics15082092] [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: 07/25/2023] [Revised: 08/04/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023] Open
Abstract
The neurotensin subtype 1 receptor (NTS1R) is overexpressed in a number of human tumors, thereby representing a valid target for cancer theranostics with radiolabeled neurotensin (NT) analogs like [99mTc]Tc-DT1 (DT1, N4-Gly7-NT(8-13)). Thus far, the fast degradation of intravenously injected NT-radioligands by neprilysin (NEP) and angiotensin-converting enzyme (ACE) has compromised their clinical applicability. Aiming at metabolic stability enhancements, we herein introduce (i) DT7 ([DAsn14]DT1) and (ii) DT8 ([β-Homoleucine13]DT1), modified at the C-terminus, along with (iii) DT9 ([(palmitoyl)Lys7]DT1), carrying an albumin-binding domain (ABD) at Lys7. The biological profiles of the new [99mTc]Tc-radioligands were compared with [99mTc]Tc-DT1, using NTS1R-expressing AsPC-1 cells and mice models without or during NEP/ACE inhibition. The radioligands showed enhanced in vivo stability vs. [99mTc]Tc-DT1, with [99mTc]Tc-DT9 displaying full resistance to both peptidases. Furthermore, [99mTc]Tc-DT9 achieved the highest cell internalization and tumor uptake even without NEP/ACE-inhibition but with unfavorably high background radioactivity levels. Hence, unlike C-terminal modification, the introduction of a pendant ABD group in the linker turned out to be the most promising strategy toward metabolic stability, cell uptake, and tumor accumulation of [99mTc]Tc-DT1 mimics. To improve the observed suboptimal pharmacokinetics of [99mTc]Tc-DT9, the replacement of palmitoyl on Lys7 by other ABD groups is currently being pursued.
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Affiliation(s)
| | - Berthold A. Nock
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (B.A.N.)
| | - Eric P. Krenning
- Cyclotron Rotterdam BV, Erasmus MC, 3015 CE Rotterdam, The Netherlands;
| | - Theodosia Maina
- Cyclotron Rotterdam BV, Erasmus MC, 3015 CE Rotterdam, The Netherlands;
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3
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Kanellopoulos P, Nock BA, Krenning EP, Maina T. Optimizing the Profile of [ 99mTc]Tc-NT(7-13) Tracers in Pancreatic Cancer Models by Means of Protease Inhibitors. Int J Mol Sci 2020; 21:ijms21217926. [PMID: 33114537 PMCID: PMC7663772 DOI: 10.3390/ijms21217926] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/22/2020] [Accepted: 10/24/2020] [Indexed: 12/17/2022] Open
Abstract
Background: The overexpression of neurotensin subtype 1 receptors (NTS1Rs) in human tumors may be elegantly exploited for directing neurotensin (NT)-based radionuclide carriers specifically to cancer sites for theranostic purposes. We have recently shown that [99mTc]Tc–DT1 ([99mTc]Tc–[N4–Gly7]NT(7–13)) and [99mTc]Tc–DT5 ([99mTc]Tc–[N4–βAla7,Dab9]NT(7–13)) show notably improved uptake in human colon adenocarcinoma WiDr xenografts in mice treated with neprilysin (NEP) inhibitors and/or angiotensin-converting enzyme (ACE) inhibitors compared with untreated controls. Aiming toward translation of this promising approach in NTS1R-positive pancreatic ductal adenocarcinoma (PDAC) patients, we now report on the impact of registered NEP/ACE inhibitors on the performance of [99mTc]Tc–DT1 and [99mTc]Tc–DT5 in pancreatic cancer models. Methods: The cellular uptake of [99mTc]Tc–DT1 and [99mTc]Tc–DT5 was tested in a panel of pancreatic cell lines, and their stability was assessed in mice treated or not treated with Entresto, lisinopril, or their combinations. Biodistribution was conducted in severe combined immunodeficiency (SCID) mice bearing pancreatic AsPC-1 xenografts. Results: The Entresto + lisinopril combination maximized the metabolic stability of the fast-internalizing [99mTc]Tc–DT1 in mice, resulting in notably enhanced tumor uptake (7.05 ± 0.80% injected activity (IA)/g vs. 1.25 ± 0.80% IA/g in non-treated controls at 4 h post-injection; p < 0.0001). Conclusions: This study has shown the feasibility of optimizing the uptake of [99mTc]Tc–DT1 in pancreatic cancer models with the aid of clinically established NEP/ACE inhibitors, in favor of clinical translation prospects.
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Affiliation(s)
- Panagiotis Kanellopoulos
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece;
- Molecular Pharmacology, School of Medicine, University of Crete, Heraklion, 70013 Crete, Greece
- Correspondence: (P.K.); (T.M.); Tel.: +30-210-650-3891 (P.K.); +30-210-650-3908 (T.M.)
| | - Berthold A. Nock
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece;
| | - Eric P. Krenning
- Cyclotron Rotterdam BV, Erasmus MC, 3015 CE Rotterdam, The Netherlands;
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece;
- Correspondence: (P.K.); (T.M.); Tel.: +30-210-650-3891 (P.K.); +30-210-650-3908 (T.M.)
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4
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Kanellopoulos P, Kaloudi A, de Jong M, Krenning EP, Nock BA, Maina T. Key-Protease Inhibition Regimens Promote Tumor Targeting of Neurotensin Radioligands. Pharmaceutics 2020; 12:pharmaceutics12060528. [PMID: 32526874 PMCID: PMC7356968 DOI: 10.3390/pharmaceutics12060528] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/05/2020] [Accepted: 06/06/2020] [Indexed: 02/06/2023] Open
Abstract
Neurotensin subtype 1 receptors (NTS1R) represent attractive molecular targets for directing radiolabeled neurotensin (NT) analogs to tumor lesions for diagnostic and therapeutic purposes. This approach has been largely undermined by the rapid in vivo degradation of linear NT-based radioligands. Herein, we aim to increase the tumor targeting of three 99mTc-labeled NT analogs by the in-situ inhibition of two key proteases involved in their catabolism. DT1 ([N4-Gly7]NT(7-13)), DT5 ([N4-βAla7,Dab9]NT(7-13)), and DT6 ([N4-βAla7,Dab9,Tle12]]NT(7-13)) were labeled with 99mTc. Their profiles were investigated in NTS1R-positive colon adenocarcinoma WiDr cells and mice treated or not with the neprilysin (NEP)-inhibitor phosphoramidon (PA) and/or the angiotensin converting enzyme (ACE)-inhibitor lisinopril (Lis). Structural modifications led to the partial stabilization of 99mTc-DT6 in peripheral mice blood (55.1 ± 3.9% intact), whereas 99mTc-DT1 and 99mTc-DT5 were totally degraded within 5 min. Coinjection of PA and/or Lis significantly stabilized all three analogs, leading to a remarkable enhancement of tumor uptake for 99mTc-DT1 and 99mTc-DT5, but was less effective in the case of poorly internalizing 99mTc-DT6. In conclusion, NEP and/or ACE inhibition represents a powerful tool to improve tumor targeting and the overall pharmacokinetics of NT-based radioligands, and warrants further validation in the field of NTS1R-targeted tumor imaging and therapy.
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Affiliation(s)
- Panagiotis Kanellopoulos
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (A.K.); (B.A.N.)
- Molecular Pharmacology, School of Medicine, University of Crete, 70013 Heraklion, Greece
| | - Aikaterini Kaloudi
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (A.K.); (B.A.N.)
| | - Marion de Jong
- Department of Radiology & Nuclear Medicine Erasmus MC, 3015 CN Rotterdam, The Netherlands;
| | - Eric P. Krenning
- Cyclotron Rotterdam BV, Erasmus MC, 3015 CE Rotterdam, The Netherlands;
| | - Berthold A. Nock
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (A.K.); (B.A.N.)
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (A.K.); (B.A.N.)
- Correspondence: ; Tel.: +30-210-650-3908
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5
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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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6
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Abstract
Single photon emission computed tomography (SPECT) is the state-of-the-art imaging modality in nuclear medicine despite the fact that only a few new SPECT tracers have become available in the past 20 years. Critical for the future success of SPECT is the design of new and specific tracers for the detection, localization, and staging of a disease and for monitoring therapy. The utility of SPECT imaging to address oncologic questions is dependent on radiotracers that ideally exhibit excellent tissue penetration, high affinity to the tumor-associated target structure, specific uptake and retention in the malignant lesions, and rapid clearance from non-targeted tissues and organs. In general, a target-specific SPECT radiopharmaceutical can be divided into two main parts: a targeting biomolecule (e.g., peptide, antibody fragment) and a γ-radiation-emitting radionuclide (e.g., 99mTc, 123I). If radiometals are used as the radiation source, a bifunctional chelator is needed to link the radioisotope to the targeting entity. In a rational SPECT tracer design, these single components have to be critically evaluated in order to achieve a balance among the demands for adequate target binding, and a rapid clearance of the radiotracer. The focus of this chapter is to depict recent developments of tumor-targeted SPECT radiotracers for imaging of cancer diseases. Possibilities for optimization of tracer design and potential causes for design failure are discussed and highlighted with selected examples.
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7
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Schindler L, Bernhardt G, Keller M. Modifications at Arg and Ile Give Neurotensin(8-13) Derivatives with High Stability and Retained NTS 1 Receptor Affinity. ACS Med Chem Lett 2019; 10:960-965. [PMID: 31223455 DOI: 10.1021/acsmedchemlett.9b00122] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/10/2019] [Indexed: 12/16/2022] Open
Abstract
Due to its expression in various malignant tumors, the neurotensin receptor 1 (NTS1R) has been suggested and explored as a target for tumor diagnosis and therapy. Animal model-based investigations of various radiolabeled NTS1R ligands derived from the hexapeptide neurotensin(8-13) (NT(8-13)), e.g. 68Ga- and 18F-labeled compounds for PET diagnostics, give rise to optimize such radiotracers for clinical use. As NT(8-13) is rapidly degraded in vivo; structural modifications are required in terms of increased metabolic stability. In this study, the stabilization of the peptide backbone of NT(8-13) against enzymatic degradation was systematically explored by performing an N-methyl scan, replacing Ile12 by tert-butylglycine12 (Tle12) and N-terminal acylation. N-Methylation of either arginine, Arg8, or Arg9, combined with the Ile12/Tle12 exchange, proved to be most favorable with respect to NTS1R affinity (K i < 2 nM) and stability in human plasma (t 1/2 > 48 h), a valuable result regarding the development of radiopharmaceuticals derived from NT(8-13).
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Affiliation(s)
- Lisa Schindler
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Günther Bernhardt
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Max Keller
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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8
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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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9
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Debordeaux F, Chansel-Debordeaux L, Pinaquy JB, Fernandez P, Schulz J. What about αvβ3 integrins in molecular imaging in oncology? Nucl Med Biol 2018; 62-63:31-46. [DOI: 10.1016/j.nucmedbio.2018.04.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/19/2018] [Accepted: 04/30/2018] [Indexed: 10/17/2022]
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10
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Maschauer S, Prante O. Radiopharmaceuticals for imaging and endoradiotherapy of neurotensin receptor-positive tumors. J Labelled Comp Radiopharm 2018; 61:309-325. [DOI: 10.1002/jlcr.3581] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 10/13/2017] [Accepted: 10/24/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Simone Maschauer
- Molecular Imaging and Radiochemistry, Department of Nuclear Medicine; Friedrich Alexander University Erlangen-Nürnberg (FAU); Erlangen Germany
| | - Olaf Prante
- Molecular Imaging and Radiochemistry, Department of Nuclear Medicine; Friedrich Alexander University Erlangen-Nürnberg (FAU); Erlangen Germany
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11
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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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12
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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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13
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Jia Y, Zhang W, Fan W, Brusnahan S, Garrison J. Investigation of the Biological Impact of Charge Distribution on a NTR1-Targeted Peptide. Bioconjug Chem 2016; 27:2658-2668. [PMID: 27661393 DOI: 10.1021/acs.bioconjchem.6b00418] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The neurotensin receptor 1 (NTR1) has been shown to be a promising target, due to its increased level of expression relative to normal tissue, for pancreatic and colon cancers. This has prompted the development of a variety of NTR1-targeted radiopharmaceuticals, based on the neurotensin (NT) peptide, for diagnostic and radiotherapeutic applications. A major obstacle for the clinical translation of NTR1-targeted radiotherapeutics would likely be nephrotoxicity due to the high levels of kidney retention. It is well-known that for many peptide-based agents, renal uptake is influenced by the overall molecular charge. Herein, we investigated the effect of charge distribution on receptor binding and kidney retention. Using the [(N-α-Me)Arg8,Dmt11,Tle12]NT(6-13) targeting vector, three peptides (177Lu-K2, 177Lu-K4, and 177Lu-K6), with the Lys moved closer (K6) or further away (K2) from the pharmacophore, were synthesized. In vitro competitive binding, internalization and efflux, and confocal microscopy studies were conducted using the NTR1-positive HT-29, human colon cancer cell line. The 177/natLu-K6 demonstrated the highest binding affinity (21.8 ± 1.2 nM) and the highest level of internalization (4.06% ± 0.20% of the total added amount). In vivo biodistribution, autoradiography, and metabolic studies of 177Lu-radiolabeled K2, K4, and K6 were examined using CF-1 mice. 177Lu-K4 and 177Lu-K6 gave the highest levels of in vivo uptake in NTR1-positive tissues, whereas 177Lu-K2 yielded nearly 2-fold higher renal uptake relative to the other radioconjugates. In conclusion, the position of the Lys (positively charged amino acid) influences the receptor binding, internalization, in vivo NTR1-targeting efficacy, and kidney retention profile of the radioconjugates. In addition, we have found that hydrophobicity likely play a role in the unique biodistribution profiles of these agents.
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Affiliation(s)
- Yinnong Jia
- Department of Pharmaceutical Sciences, College of Pharmacy, ‡Center for Drug Delivery and Nanomedicine, §Department of Biochemistry and Molecular Biology, College of Medicine, and ∥Eppley Cancer Center, University of Nebraska Medical Center , Omaha, Nebraska 985830, United States
| | - Wenting Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy, ‡Center for Drug Delivery and Nanomedicine, §Department of Biochemistry and Molecular Biology, College of Medicine, and ∥Eppley Cancer Center, University of Nebraska Medical Center , Omaha, Nebraska 985830, United States
| | - Wei Fan
- Department of Pharmaceutical Sciences, College of Pharmacy, ‡Center for Drug Delivery and Nanomedicine, §Department of Biochemistry and Molecular Biology, College of Medicine, and ∥Eppley Cancer Center, University of Nebraska Medical Center , Omaha, Nebraska 985830, United States
| | - Susan Brusnahan
- Department of Pharmaceutical Sciences, College of Pharmacy, ‡Center for Drug Delivery and Nanomedicine, §Department of Biochemistry and Molecular Biology, College of Medicine, and ∥Eppley Cancer Center, University of Nebraska Medical Center , Omaha, Nebraska 985830, United States
| | - Jered Garrison
- Department of Pharmaceutical Sciences, College of Pharmacy, ‡Center for Drug Delivery and Nanomedicine, §Department of Biochemistry and Molecular Biology, College of Medicine, and ∥Eppley Cancer Center, University of Nebraska Medical Center , Omaha, Nebraska 985830, United States
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14
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Maschauer S, Einsiedel J, Hübner H, Gmeiner P, Prante O. 18F- and 68Ga-Labeled Neurotensin Peptides for PET Imaging of Neurotensin Receptor 1. J Med Chem 2016; 59:6480-92. [DOI: 10.1021/acs.jmedchem.6b00675] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Simone Maschauer
- Department
of Nuclear Medicine, Molecular Imaging and Radiochemistry, Friedrich-Alexander University (FAU), Schwabachanlage 6, 91054 Erlangen, Germany
| | - Jürgen Einsiedel
- Department
of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, Friedrich-Alexander University (FAU), Schuhstraße 19, 91052 Erlangen, Germany
| | - Harald Hübner
- Department
of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, Friedrich-Alexander University (FAU), Schuhstraße 19, 91052 Erlangen, Germany
| | - Peter Gmeiner
- Department
of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, Friedrich-Alexander University (FAU), Schuhstraße 19, 91052 Erlangen, Germany
| | - Olaf Prante
- Department
of Nuclear Medicine, Molecular Imaging and Radiochemistry, Friedrich-Alexander University (FAU), Schwabachanlage 6, 91054 Erlangen, Germany
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15
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Mascarin A, Valverde IE, Mindt TL. Structure-Activity Relationship Studies of Amino Acid Substitutions in Radiolabeled Neurotensin Conjugates. ChemMedChem 2015; 11:102-7. [PMID: 26593062 DOI: 10.1002/cmdc.201500468] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Indexed: 11/06/2022]
Abstract
Radiolabeled derivatives of the peptide neurotensin (NT) and its binding sequence NT(8-13) have been studied as potential imaging probes and therapeutics for NT-1-receptor-positive cancer. However, a direct comparison of reported NT analogues, even if radiolabeled with the same radionuclide, is difficult because different techniques and models have been used for preclinical evaluations. In an effort to identify a suitable derivative of NT(8-13) for radiotracer development, we herein report a side-by-side in vitro comparison of radiometallated NT derivatives bearing some of the most commonly reported amino acid substitutions in their sequence. Performed investigations include cell internalization experiments, determinations of receptor affinity, measurements of the distribution coefficient, and blood serum stability studies. Of the [(177)Lu]-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-labeled examples studied, analogues of NT(8-13) containing a short hydrophilic tetraethylene glycol (PEG4 ) spacer between the peptide and the radiometal complex, and a minimum number of substitutions of amino acid residues, exhibited the most promising properties in vitro.
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Affiliation(s)
- Alba Mascarin
- Division of Radiopharmaceutical Chemistry, University of Basel Hospital, Petersgraben 4, 4031, Basel, Switzerland
| | - Ibai E Valverde
- Division of Radiopharmaceutical Chemistry, University of Basel Hospital, Petersgraben 4, 4031, Basel, Switzerland
| | - Thomas L Mindt
- Division of Radiopharmaceutical Chemistry, University of Basel Hospital, Petersgraben 4, 4031, Basel, Switzerland. .,Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland.
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Körner M, Waser B, Strobel O, Büchler M, Reubi JC. Neurotensin receptors in pancreatic ductal carcinomas. EJNMMI Res 2015; 5:17. [PMID: 25859423 PMCID: PMC4388205 DOI: 10.1186/s13550-015-0094-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 02/26/2015] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The frequent expression of neurotensin receptors (NT-R) in primaries of pancreatic ductal carcinomas has triggered the development of radioactive neurotensin analogs for possible in vivo targeting of these tumors. However, the complete lack of information regarding NT-R in liver metastases of pancreatic cancer and pancreatic intraepithelial neoplasia (PanIN) makes an in vitro study of NT-R in these tissues indispensable. METHODS Using in vitro receptor autoradiography with (125)I-[Tyr(3)]-neurotensin, NT-R were investigated in 18 primaries and 23 liver metastases of pancreatic ductal carcinomas as well as in 19 PanIN lesions. RESULTS We report here that 13 of 18 ductal carcinoma primaries and 14 of 23 liver metastases expressed NT-R. Moreover, none of the six PanIN 1B cases expressed NT-R, while two of six PanIN 2 and five of seven PanIN 3 expressed NT-R. Binding was fully displaced by the type 1 NT-R-selective antagonist SR48692, indicating that the NT-R in the tumors are of the type 1 NT-R subtype. CONCLUSIONS These in vitro data extend the currently available information on NT-R in invasive and non-invasive pancreatic ductal tumors. They suggest that type 1 NT-R may be a novel, specific marker of PanIN of higher degree. The high expression of NT-R in primaries and metastases of invasive cancer strongly support the need to develop radioactive neurotensin analogs for the diagnosis and therapy of this tumor type.
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Affiliation(s)
- Meike Körner
- Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, PO Box 62, Murtenstrasse 31, CH-3010 Berne, Switzerland
| | - Beatrice Waser
- Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, PO Box 62, Murtenstrasse 31, CH-3010 Berne, Switzerland
| | - Oliver Strobel
- Department of General, Visceral and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Markus Büchler
- Department of General, Visceral and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Jean Claude Reubi
- Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, PO Box 62, Murtenstrasse 31, CH-3010 Berne, Switzerland
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Maschauer S, Ruckdeschel T, Tripal P, Haubner R, Einsiedel J, Hübner H, Gmeiner P, Kuwert T, Prante O. In vivo monitoring of the antiangiogenic effect of neurotensin receptor-mediated radiotherapy by small-animal positron emission tomography: a pilot study. Pharmaceuticals (Basel) 2014; 7:464-81. [PMID: 24743103 PMCID: PMC4014703 DOI: 10.3390/ph7040464] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 04/04/2014] [Accepted: 04/10/2014] [Indexed: 12/22/2022] Open
Abstract
The neurotensin receptor (NTS1) has emerged as an interesting target for molecular imaging and radiotherapy of NTS-positive tumors due to the overexpression in a range of tumors. The aim of this study was to develop a 177Lu-labeled NTS1 radioligand, its application for radiotherapy in a preclinical model and the imaging of therapy success by small-animal positron emission tomography (µPET) using [68Ga]DOTA-RGD as a specific tracer for imaging angiogenesis. The 177Lu-labeled peptide was subjected to studies on HT29-tumor-bearing nude mice in vivo, defining four groups of animals (single dose, two fractionated doses, four fractionated doses and sham-treated animals). Body weight and tumor diameters were determined three times per week. Up to day 28 after treatment, µPET studies were performed with [68Ga]DOTA-RGD. At days 7–10 after treatment with four fractionated doses of 11–14 MBq (each at days 0, 3, 6 and 10), the tumor growth was slightly decreased in comparison with untreated animals. Using a single high dose of 51 MBq, a significantly decreased tumor diameter of about 50% was observed with the beginning of treatment. Our preliminary PET imaging data suggested decreased tumor uptake values of [68Ga]DOTA-RGD in treated animals compared to controls at day 7 after treatment. This pilot study suggests that early PET imaging with [68Ga]DOTA-RGD in radiotherapy studies to monitor integrin expression could be a promising tool to predict therapy success in vivo. Further successive PET experiments are needed to confirm the significance and predictive value of RGD-PET for NTS-mediated radiotherapy.
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Affiliation(s)
- Simone Maschauer
- Department of Nuclear Medicine, Laboratory of Molecular Imaging and Radiochemistry, Friedrich Alexander University, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Tina Ruckdeschel
- Department of Nuclear Medicine, Laboratory of Molecular Imaging and Radiochemistry, Friedrich Alexander University, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Philipp Tripal
- Department of Nuclear Medicine, Laboratory of Molecular Imaging and Radiochemistry, Friedrich Alexander University, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Roland Haubner
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstr. 35, 6020 Innsbruck, Austria.
| | - Jürgen Einsiedel
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, Friedrich Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
| | - Harald Hübner
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, Friedrich Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, Friedrich Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
| | - Torsten Kuwert
- Department of Nuclear Medicine, Laboratory of Molecular Imaging and Radiochemistry, Friedrich Alexander University, Schwabachanlage 6, 91054 Erlangen, Germany.
| | - Olaf Prante
- Department of Nuclear Medicine, Laboratory of Molecular Imaging and Radiochemistry, Friedrich Alexander University, Schwabachanlage 6, 91054 Erlangen, Germany.
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Erfani M, Zarrabi Ahrabi N, Shafiei M, Shirmardi SP. A (99m) Tc-tricine-HYNIC-labeled peptide targeting the neurotensin receptor for single-photon imaging in malignant tumors. J Labelled Comp Radiopharm 2014; 57:125-31. [PMID: 24395489 DOI: 10.1002/jlcr.3176] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/19/2013] [Accepted: 11/27/2013] [Indexed: 11/06/2022]
Abstract
In this study, a new neurotensin (NT) analog was labeled with (99m) Tc via HYNIC chelator and tricine as coligand and investigated further. An NT (7-13) analog was prepared, and labeling with (99m) Tc was performed. The internalization rate and biodistribution of radiopeptide were studied in HT-29 cells and nude mice bearing tumor, respectively. Radiolabeling with (99m) Tc was performed at high specific activities (54 MBq/nmol) with an acceptable labeling yield (>95%). In vitro cell line studies showed a specific internalization uptake up to 13.23 ± 0.45% during 4 h which was blocked in the presence of excess cold peptide to 0.83 ± 0.15%. In biodistribution studies, uptake was observed in NT receptor-positive organs so that after 1 h the uptakes in mouse intestine and tumor were 1.23 ± 0.16% ID/g and 1.12 ± 0.11% ID/g, respectively. In animals co-injected with excess cold peptide, reduction uptake in tumor and intestines were 73% (1.10% vs. 0.29% ID/g at 4 h) and 61% (1.22% vs. 0.47% ID/g at 4 h) respectively. Predominant renal excretion pathway with a highest accumulation of activity in bladder was observed for this radiopeptide. This radiolabeled peptide could be a candidate for detection of NT positive tumors.
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Affiliation(s)
- Mostafa Erfani
- Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI), PO Box: 11365-3486, end of Karegar Ave., Tehran, Iran
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Ahrabi NZ, Erfani M, Parivar K, Beiki D, Jalilian AR. Preparation and evaluation of a new neurotensin analog labeled with 99mTc for targeted imaging of neurotensin receptor positive tumors. J Radioanal Nucl Chem 2013. [DOI: 10.1007/s10967-013-2795-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
Single photon emission computed tomography (SPECT) is the state-of-the-art imaging modality in nuclear medicine despite the fact that only a few new SPECT tracers have become available in the past 20 years. Critical for the future success of SPECT is the design of new and specific tracers for the detection, localization, and staging of a disease and for monitoring therapy. The utility of SPECT imaging to address oncologic questions is dependent on radiotracers that ideally exhibit excellent tissue penetration, high affinity to the tumor-associated target structure, specific uptake and retention in the malignant lesions, and rapid clearance from non-targeted tissues and organs. In general, a target-specific SPECT radiopharmaceutical can be divided into two main parts: a targeting biomolecule (e.g. peptide, antibody fragment) and a γ-radiation emitting radionuclide (e.g. (99m)Tc, (123)I). If radiometals are used as the radiation source, a bifunctional chelator is needed to link the radioisotope to the targeting entity. In a rational SPECT tracer design these single components have to be critically evaluated in order to achieve a balance among the demands for adequate target binding, and a rapid clearance of the radiotracer. The focus of this chapter is to depict recent developments of tumor-targeted SPECT radiotracers for imaging of cancer diseases. Possibilities for optimization of tracer design and potential causes for design failure are discussed and highlighted with selected examples.
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Affiliation(s)
- Cristina Müller
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland.
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Seebach D, Lukaszuk A, Patora-Komisarska K, Podwysocka D, Gardiner J, Ebert MO, Reubi JC, Cescato R, Waser B, Gmeiner P, Hübner H, Rougeot C. On the Terminal Homologation of Physiologically Active Peptides as a Means of Increasing Stability in Human Serum - Neurotensin, Opiorphin, B27-KK10 Epitope, NPY. Chem Biodivers 2011; 8:711-39. [DOI: 10.1002/cbdv.201100093] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Einsiedel J, Held C, Hervet M, Plomer M, Tschammer N, Hübner H, Gmeiner P. Discovery of Highly Potent and Neurotensin Receptor 2 Selective Neurotensin Mimetics. J Med Chem 2011; 54:2915-23. [DOI: 10.1021/jm200006c] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jürgen Einsiedel
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Cornelia Held
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Maud Hervet
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Manuel Plomer
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Nuska Tschammer
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Harald Hübner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
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Chen K, Chen X. Design and development of molecular imaging probes. Curr Top Med Chem 2011; 10:1227-36. [PMID: 20388106 DOI: 10.2174/156802610791384225] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 02/27/2010] [Indexed: 01/17/2023]
Abstract
Molecular imaging, the visualization, characterization and measurement of biological processes at the cellular, subcellular level, or even molecular level in living subjects, has rapidly gained importance in the dawning era of personalized medicine. Molecular imaging takes advantage of the traditional diagnostic imaging techniques and introduces molecular imaging probes to determine the expression of indicative molecular markers at different stages of diseases and disorders. As a key component of molecular imaging, molecular imaging probe must be able to specifically reach the target of interest in vivo while retaining long enough to be detected. A desirable molecular imaging probe with clinical translation potential is expected to have unique characteristics. Therefore, design and development of molecular imaging probe is frequently a challenging endeavor for medicinal chemists. This review summarizes the general principles of molecular imaging probe design and some fundamental strategies of molecular imaging probe development with a number of illustrative examples.
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Affiliation(s)
- Kai Chen
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
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Pratsch G, Unfried JF, Einsiedel J, Plomer M, Hübner H, Gmeiner P, Heinrich MR. Radical arylation of tyrosine and its application in the synthesis of a highly selective neurotensin receptor 2 ligand. Org Biomol Chem 2011; 9:3746-52. [DOI: 10.1039/c1ob05292f] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Teodoro R, Faintuch BL, Núñez EGF, Queiróz RG. Neurotensin(8-13) analogue: radiolabeling and biological evaluation using different chelators. Nucl Med Biol 2010; 38:113-20. [PMID: 21220134 DOI: 10.1016/j.nucmedbio.2010.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 06/01/2010] [Accepted: 06/14/2010] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Several strategies on the development of radiopharmaceuticals have been employed. Bifunctional chelators seem to be a promising approach since high radiochemical yields as well as good in vitro and in vivo stability have been achieved. To date, neurotensin analogs have been radiolabeled using the (99m)Tc-carbonyl approach and none was described employing the bifunctional chelating agent technique. AIM The purpose of this study was to evaluate the radiochemical and biological behaviour of NT(8-13) analogue radiolabeled with (99m)Tc, using HYNIC and NHS-S-acetyl-MAG(3) as chelator agents. METHODS Radiolabeling, in vitro stability toward cysteine and glutathione, partition coefficient and plasma protein binding were assessed for both radioconjugates. Biodistribution in healthy Swiss mice were carried out in order to evaluate the biological behaviour of the radiocomplexes. RESULTS Radiochemical yields were higher than 97% and no apparent instability toward transchelant agents was observed for both radioconjugates. A higher lipophilic character was observed for the radioconjugate labeled via MAG(3). The chelators seem to have no effect on the percentage of the radioconjugate bound to plasma proteins. A similar biological pattern was observed for both radioconjugates. Total blood, bone and muscle values revealed a slightly slower clearance for the radiocomplex labeled via MAG(3). Moreover, a remarkable liver and intestinal uptake was observed for the radiocomplex labeled via MAG(3) even at the later time points studied. CONCLUSION The high radiochemical yields achieved and the similar in vivo pattern found for both radioconjugates make them potential candidates for imaging tumors using nuclear medicine techniques.
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Affiliation(s)
- Rodrigo Teodoro
- Center of Radiopharmacy, Institute of Energetic and Nuclear Research, Sao Paulo, SP 05508-000, Brazil.
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Maschauer S, Einsiedel J, Hocke C, Hübner H, Kuwert T, Gmeiner P, Prante O. Synthesis of a (68)ga-labeled peptoid-Peptide hybrid for imaging of neurotensin receptor expression in vivo. ACS Med Chem Lett 2010; 1:224-8. [PMID: 24900199 DOI: 10.1021/ml1000728] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 05/14/2010] [Indexed: 12/11/2022] Open
Abstract
The neurotensin receptor subtype 1 (NTS1) represents an attractive molecular target for imaging various tumors. Positron emission tomography (PET) gained widespread importance due to its sensitivity. We combined the design of a metabolically stable neurotensin analogue with a (68)Ga-radiolabeling approach. The (68)Ga-labeled peptoid-peptide hybrid [(68)Ga]3 revealed high stability, specific tumor uptake (0.7%ID/g, 65 min p.i.), and advantageous biokinetics in vivo using HT29 tumor-bearing nude mice. Because of the ability to internalize into NTS1-expressing tumor cells, [(68)Ga]3 proved to be highly suitable for a reliable and practical visualization of NTS1-expressing tumors in vivo by small animal PET.
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Affiliation(s)
- Simone Maschauer
- Laboratory of Molecular Imaging, Clinic of Nuclear Medicine, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany
| | | | - Carsten Hocke
- Laboratory of Molecular Imaging, Clinic of Nuclear Medicine, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Harald Hübner
- Department of Chemisty and Pharmacy, Emil Fischer Center
| | - Torsten Kuwert
- Laboratory of Molecular Imaging, Clinic of Nuclear Medicine, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemisty and Pharmacy, Emil Fischer Center
| | - Olaf Prante
- Laboratory of Molecular Imaging, Clinic of Nuclear Medicine, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany
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Shimamura K, Matsuda M, Miyamoto Y, Yoshimoto R, Seo T, Tokita S. Identification of a stable chemerin analog with potent activity toward ChemR23. Peptides 2009; 30:1529-38. [PMID: 19540290 DOI: 10.1016/j.peptides.2009.05.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 05/20/2009] [Accepted: 05/20/2009] [Indexed: 02/02/2023]
Abstract
Chemerin is a novel peptide that was identified as a natural ligand for ChemR23. As it has been reported to be involved in the regulation of immune responses and adipogenesis, chemerin may have a variety of physiological functions. Chemerin is synthesized as a precursor (prochemerin) and is proteolytically activated and inactivated in sequential steps, which control its physiological roles in a coordinated manner. Chemerin-9 (chemerin148-156) was previously identified as the smallest peptide with low nanomolar potency. However, like mature chemerin, chemerin-9 is rapidly degraded and inactivated in plasma, which has limited the use of chemerin-9 in in vivo experiments. In order to identify stable chemerin analogs that facilitate in vivo studies, we synthesized a series of chemerin-9 analogs and examined intrinsic activity and metabolic stability. We identified an agonistic and metabolically stable chemerin-9 analog (d-Tyr(147)-[d-Ser(151), d-Ala(154), Tic(155)]chemerin148-156) that shows enhanced plasma exposure with prolonged half-life in mice upon intraperitoneal administration. Improvement of metabolic stability resulted in a reduction in the plasma free fatty acid levels in fasted mice, which cannot be accomplished by unstable-mouse chemerin-9. This reduction in plasma free fatty acids reflects the anti-lipolysis activity of chemerin-9 and analogs in mouse primary adipocytes. The discovery of a metabolically stable chemerin analog will facilitate investigation of the pharmacological roles of chemerin in vivo. Moreover, this stable chemerin analog might provide new therapeutic approaches to inflammatory diseases such as asthma and metabolic disorders such as obesity and diabetes where ChemR23 activation may be of benefit.
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Affiliation(s)
- Ken Shimamura
- Department of Metabolic Disorder Research, Tsukuba Research Institute, BANYU Pharmaceutical Co., Ltd., Okubo 3, Tsukuba, Ibaraki 300-2611, Japan
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Schottelius M, Wester HJ. Molecular imaging targeting peptide receptors. Methods 2009; 48:161-77. [DOI: 10.1016/j.ymeth.2009.03.012] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Accepted: 03/11/2009] [Indexed: 02/08/2023] Open
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Zhang L, Lee HK, Pruess TH, White HS, Bulaj G. Synthesis and applications of polyamine amino acid residues: improving the bioactivity of an analgesic neuropeptide, neurotensin. J Med Chem 2009; 52:1514-7. [PMID: 19236044 DOI: 10.1021/jm801481y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conjugated polyamines are potential carriers for biotherapeutics targeting the central nervous system. We describe an efficient synthesis of a polyamine-based amino acid, lysine-trimethylene(diNosyl)-spermine(triBoc) with Dde or Fmoc orthogonal protecting groups. This nonnatural amino acid was incorporated into a neurotensin analogue using standard Fmoc-based protocols. The analogue maintained high affinity and agonist potency for neurotensin receptors and exhibited dramatically improved analgesia in mice. Our work provides a basis for use of polyamine amino acids in polypeptides.
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Affiliation(s)
- Liuyin Zhang
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108, USA
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Brans L, Maes V, García-Garayoa E, Schweinsberg C, Daepp S, Bläuenstein P, Schubiger PA, Schibli R, Tourwé DA. Glycation methods for bombesin analogs containing the (NalphaHis)Ac chelator for 99mTc(CO)3 radiolabeling. Chem Biol Drug Des 2008; 72:496-506. [PMID: 19016795 DOI: 10.1111/j.1747-0285.2008.00727.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The overexpression of peptide receptors in a variety of human carcinomas has generated considerable interest in peptide-based radiopharmaceuticals for peptide receptor imaging and peptide receptor radiotherapy. The gastrin-releasing peptide receptor is overexpressed in human prostate-, breast-, colon- and small cell lung carcinoma cells. We have developed metabolically stable (99m)Tc-radiolabeled bombesin ([Cha(13), Nle(14)]BBS(7-14)) analogs, which bind with high affinity to the gastrin-releasing peptide receptors. However, because of their lipophilicity, they showed unfavorable biodistribution with high hepatic accumulation and hepatobiliary excretion. We now report a study of different glycation methods for [Cha(13), Nle(14)]BBS(7-14) analogs to improve their biodistribution profile. Whereas the glycation using the Maillard reaction was problematic, resulting in low yields, selective introduction of the glycomimetic shikimic acid to the side chain of a Lys residue was possible. A chemoselective ligation of alpha-D-glucose to an amino-oxyacetylated [Cha(13), Nle(14)]BBS(7-14) analog could be achieved, but was complicated by the co-elution of starting peptide and glycopeptide. The best procedure consisted of the [1,3]-cycloaddition of N(3)-beta-D-glucose to a propargylglycine-containing [Cha(13), Nle(14)]BBS(7-14) analog, using a catalytic amount of Cu(I)I. All glycated [Cha(13), Nle(14)]BBS(7-14) analogs showed high affinity for the gastrin-releasing peptide receptor and rapid accumulation into PC-3 tumor cells.
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Affiliation(s)
- Luc Brans
- Department of Organic Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
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Bourgault S, Vaudry D, Botia B, Couvineau A, Laburthe M, Vaudry H, Fournier A. Novel stable PACAP analogs with potent activity towards the PAC1 receptor. Peptides 2008; 29:919-32. [PMID: 18353507 DOI: 10.1016/j.peptides.2008.01.022] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 01/17/2008] [Accepted: 01/24/2008] [Indexed: 02/08/2023]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a 38- or 27-amino acid neuropeptide with promising therapeutic applications for the treatment of several pathophysiological states related to neurodegenerative diseases. However, its use for therapeutic applications is actually limited by its restricted bioavailability and rapid degradation. Therefore, metabolically stable PACAP analogs represent promising tools to further investigate the physiological roles of PACAP and ascertain its usefulness in some clinical conditions. In this study, derivatives of PACAP27 and PACAP38 have been rationally designed to develop PAC1 receptor agonists resistant to peptidase action. Results showed that N-terminal modifications confer resistance to dipeptidyl peptidase IV, a major proteolytic process involved in PACAP degradation. Moreover, in vitro incubation of both PACAP isoforms in human plasma revealed that PACAP38 is rapidly metabolized, with a half-life of less than 5 min, while PACAP27 was stable in these experimental conditions. Hence, following the elucidation of its plasmatic metabolites, PACAP38 was modified at its putative endopeptidase and carboxypeptidase sites of cleavage. All peptide analogs were tested for their ability to bind the PAC1 receptor, as well as for their potency to induce calcium mobilization and inhibit PC12 cell proliferation through the PAC1 receptor. This approach revealed two leading compounds, i.e. acetyl-[Ala15, Ala20]PACAP38-propylamide and acetyl-PACAP27-propylamide, which exhibited improved metabolic stability and potent biological activity. This study describes innovative data related to PACAP metabolism in human plasma and depicts the development of a metabolically stable PACAP38 analog, acetyl-[Ala15, Ala20]PACAP38-propylamide, which behaves as a super-agonist towards the PAC1 receptor.
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Affiliation(s)
- Steve Bourgault
- INRS-Institut Armand-Frappier, Institut National de la Recherche Scientifique, 531 boulevard des Prairies, Laval, H7V 1B7, Canada
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de Visser M, Verwijnen SM, de Jong M. Update:Improvement Strategies for Peptide Receptor Scintigraphy and Radionuclide Therapy. Cancer Biother Radiopharm 2008; 23:137-57. [DOI: 10.1089/cbr.2007.0435] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Monique de Visser
- Department of Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | | | - Marion de Jong
- Department of Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
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Peptide backbone modifications on the C-terminal hexapeptide of neurotensin. Bioorg Med Chem Lett 2008; 18:2013-8. [DOI: 10.1016/j.bmcl.2008.01.110] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 01/28/2008] [Accepted: 01/29/2008] [Indexed: 11/23/2022]
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Janssen PJJM, de Visser M, Verwijnen SM, Bernard BF, Srinivasan A, Erion JL, Breeman WAP, Vulto AG, Krenning EP, de Jong M. Five Stabilized 111In-labeled neurotensin analogs in nude mice bearing HT29 tumors. Cancer Biother Radiopharm 2007; 22:374-81. [PMID: 17651043 DOI: 10.1089/cbr.2007.369.a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neurotensin (NT) receptors are overexpressed in different human tumors, such as human ductal pancreatic adenocarcinoma. New stable neurotensin analogs with high receptor affinity have been synthesized by replacing arginine residues with lysine and arginine derivatives. The aim of this study was to explore the biodistribution, tumor uptake, kidney localization, and stability characteristics of these new analogs in order to develop new diagnostic tools for exocrine pancreatic cancer. Four (111)In-labeled DTPA-chelated NT analogs and one (111)In-labeled DOTA-chelated NT analog were evaluated in NMRI nude mice bearing NT receptor-positive HT29 tumors. Experiments with a coinjection of unlabeled NT or lysine were performed to investigate receptor-mediated uptake and kidney protection, respectively. In addition, the in vivo serum stability of the most promising analog was analyzed. In the biodistribution study in mice, at 4 hours postinjection, a low percentage of the injected dose per gram (%ID/g) of tissue for all compounds was found in NT receptor-negative organs, such as the blood, spleen, pancreas, liver, muscle, and femur. A high uptake was found in the colon, intestine, kidneys, and in implanted HT29 tumors. The coinjection of excess unlabeled neurotensin significantly reduced tumor uptake, showing tumor uptake to be receptor-mediated. To a lesser extent, this was also observed for the colon, but not for other tissues. We concluded that DTPA-(Pip)Gly-Pro-(PipAm)Gly-Arg-Pro-Tyr-tBuGly-Leu-OH and the DOTA-linked counterpart have the most favorable biodistribution properties regarding tumor uptake.
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Maina T, Nikolopoulou A, Stathopoulou E, Galanis AS, Cordopatis P, Nock BA. [99mTc]Demotensin 5 and 6 in the NTS1-R-targeted imaging of tumours: synthesis and preclinical results. Eur J Nucl Med Mol Imaging 2007; 34:1804-14. [PMID: 17594090 DOI: 10.1007/s00259-007-0489-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 04/22/2007] [Indexed: 11/28/2022]
Abstract
PURPOSE The aim of this study was to evaluate the applicability of [(99m)Tc]Demotensin 5 and 6 [Formula: see text] in the targeted diagnostic imaging of neurotensin subtype 1 receptor (NTS1-R)-expressing tumours. METHODS Labelling of Demotensin 5 and 6 with (99m)Tc was conducted by brief incubation with (99m)TcO(4) (-), SnCl(2) and citrate anions in alkaline medium at ambient temperature. Affinities of conjugates for the NTS1-R were determined by competition binding experiments in WiDr cell membranes using [(125)I-Tyr(3)]NT as the radioligand. Saturation binding assays were conducted for [(99m)Tc/(99g)Tc]Demotensin 6 in WiDr cell membranes. Internalisation of [(99m)Tc]Demotensin 5 and 6 was studied at 37 degrees C in WiDr cells. Biodistribution of [(99m)Tc]Demotensin 5 and 6 was performed in female Swiss nu/nu mice bearing human WiDr xenografts. RESULTS Unlabelled conjugates showed a high affinity for the human NTS1-R (Demotensin 5 IC(50)=0.03+/-0.01 nM; Demotensin 6 IC(50)=0.08+/-0.02 nM), while high affinity was also exhibited by (radio)metallated [(99m)Tc/(99g)Tc]Demotensin 6 (K (d)=0.13+/-0.01 nM). [(99m)Tc]Demotensin 5 and 6 internalised rapidly and specifically in WiDr cells. After injection in WiDr tumour-bearing mice, radiopeptides, and especially the doubly stabilised [(99m)Tc]Demotensin 6, showed NTS1-R-mediated uptake in the intestines and in the implanted tumour (4.30+/-0.45%ID/g at 1 h post injection) and rapid renal excretion from non-target tissues into the urine. CONCLUSION [(99m)Tc]Demotensin 6 shows a favourable preclinical profile and further testing in patients is warranted to monitor its eventual applicability as a radiotracer in the diagnostic imaging of NTS1-R-positive tumours.
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Affiliation(s)
- Theodosia Maina
- Institute of Radioisotopes - Radiodiagnostic Products, National Center for Scientific Research Demokritos, Ag. Paraskevi Attikis, 153 10 Athens, Greece
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