1
|
Ludwig FA, Laurini E, Schmidt J, Pricl S, Deuther-Conrad W, Wünsch B. [ 18F]Fluspidine-A PET Tracer for Imaging of σ 1 Receptors in the Central Nervous System. Pharmaceuticals (Basel) 2024; 17:166. [PMID: 38399380 PMCID: PMC10892410 DOI: 10.3390/ph17020166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/18/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
σ1 receptors play a crucial role in various neurological and neurodegenerative diseases including pain, psychosis, Alzheimer's disease, and depression. Spirocyclic piperidines represent a promising class of potent σ1 receptor ligands. The relationship between structural modifications and σ1 receptor affinity and selectivity over σ2 receptors led to the 2-fluoroethyl derivative fluspidine (2, Ki = 0.59 nM). Enantiomerically pure (S)-configured fluspidine ((S)-2) was prepared by the enantioselective reduction of the α,β-unsaturated ester 23 with NaBH4 and the enantiomerically pure co-catalyst (S,S)-24. The pharmacokinetic properties of both fluspidine enantiomers (R)-2 and (S)-2 were analyzed in vitro. Molecular dynamics simulations revealed very similar interactions of both fluspidine enantiomers with the σ1 receptor protein, with a strong ionic interaction between the protonated amino moiety of the piperidine ring and the COO- moiety of glutamate 172. The 18F-labeled radiotracers (S)-[18F]2 and (R)-[18F]2 were synthesized in automated syntheses using a TRACERlab FX FN synthesis module. High radiochemical yields and radiochemical purity were achieved. Radiometabolites were not found in the brains of mice, piglets, and rhesus monkeys. While both enantiomers revealed similar initial brain uptake, the slow washout of (R)-[18F]2 indicated a kind of irreversible binding. In the first clinical trial, (S)-[18F]2 was used to visualize σ1 receptors in the brains of patients with major depressive disorder (MDD). This study revealed an increased density of σ1 receptors in cortico-striato-(para)limbic brain regions of MDD patients. The increased density of σ1 receptors correlated with the severity of the depressive symptoms. In an occupancy study with the PET tracer (S)-[18F]2, the selective binding of pridopidine at σ1 receptors in the brain of healthy volunteers and HD patients was shown.
Collapse
Affiliation(s)
- Friedrich-Alexander Ludwig
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, D-04318 Leipzig, Germany; (F.-A.L.); (W.D.-C.)
| | - Erik Laurini
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTS), DEA, University of Trieste, 34127 Trieste, Italy; (E.L.); (S.P.)
| | - Judith Schmidt
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Corrensstraße 48, D-48149 Münster, Germany;
| | - Sabrina Pricl
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTS), DEA, University of Trieste, 34127 Trieste, Italy; (E.L.); (S.P.)
- Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 90-136 Lodz, Poland
| | - Winnie Deuther-Conrad
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, D-04318 Leipzig, Germany; (F.-A.L.); (W.D.-C.)
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Corrensstraße 48, D-48149 Münster, Germany;
- GRK 2515, Chemical Biology of Ion Channels (Chembion), Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| |
Collapse
|
2
|
Wang T, Jia H. The Sigma Receptors in Alzheimer's Disease: New Potential Targets for Diagnosis and Therapy. Int J Mol Sci 2023; 24:12025. [PMID: 37569401 PMCID: PMC10418732 DOI: 10.3390/ijms241512025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 08/13/2023] Open
Abstract
Sigma (σ) receptors are a class of unique proteins with two subtypes: the sigma-1 (σ1) receptor which is situated at the mitochondria-associated endoplasmic reticulum (ER) membrane (MAM), and the sigma-2 (σ2) receptor, located in the ER-resident membrane. Increasing evidence indicates the involvement of both σ1 and σ2 receptors in the pathogenesis of Alzheimer's disease (AD), and thus these receptors represent two potentially effective biomarkers for emerging AD therapies. The availability of optimal radioligands for positron emission tomography (PET) neuroimaging of the σ1 and σ2 receptors in humans will provide tools to monitor AD progression and treatment outcomes. In this review, we first summarize the significance of both receptors in the pathophysiology of AD and highlight AD therapeutic strategies related to the σ1 and σ2 receptors. We then survey the potential PET radioligands, with an emphasis on the requirements of optimal radioligands for imaging the σ1 or σ2 receptors in humans. Finally, we discuss current challenges in the development of PET radioligands for the σ1 or σ2 receptors, and the opportunities for neuroimaging to elucidate the σ1 and σ2 receptors as novel biomarkers for early AD diagnosis, and for monitoring of disease progression and AD drug efficacy.
Collapse
Affiliation(s)
- Tao Wang
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China;
- Department of Nuclear Medicine, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Hongmei Jia
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China;
| |
Collapse
|
3
|
Blicker L, González-Cano R, Laurini E, Nieto FR, Schmidt J, Schepmann D, Pricl S, Wünsch B. Conformationally Restricted σ 1 Receptor Antagonists from (-)-Isopulegol. J Med Chem 2023; 66:4999-5020. [PMID: 36946301 DOI: 10.1021/acs.jmedchem.2c02081] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Antagonists at σ1 receptors have great potential for the treatment of neuropathic pain. Starting from monoterpene (-)-isopulegol (1), aminodiols 8-11 were obtained and transformed into bicyclic 13-16 and tricyclic ligands 19-22. Aminodiols 8-11 showed higher σ1 affinity than the corresponding bicyclic 13-16 and tricyclic derivatives 19-22. (R)-configuration in the side chain of aminodiols (8 and 10) led to higher σ1 affinity than (S)-configuration (9 and 11). 4-Benzylpiperidines (b-series) revealed higher σ1 affinity than 4-phenylbutylamines (a-series). Aminodiol 8b showed very high σ1 affinity (Ki = 1.2 nM), excellent selectivity over σ2 receptors, and promising logD7.4 (3.05) and lipophilic ligand efficiency (5.87) values. Molecular dynamics simulations were conducted to analyze the σ1 affinity and selectivity on an atomistic level. In the capsaicin assay, 8b exhibited similar antiallodynic activity to the prototypical σ1 antagonist S1RA. The antiallodynic activity of 8b was removed by co-application of the σ1 agonist PRE-084, proving σ1 antagonism being involved in the antiallodynic effect.
Collapse
Affiliation(s)
- Luca Blicker
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Rafael González-Cano
- Department of Pharmacology, Faculty of Medicine and Biomedical Research Center (Neurosciences Institute), Biosanitary Research Institute ibs. GRANADA, University of Granada, Avenida de la Investigación 11, Granada 18016, Spain
| | - Erik Laurini
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTS), DEA, University of Trieste, 34127 Trieste, Italy
| | - Francisco R Nieto
- Department of Pharmacology, Faculty of Medicine and Biomedical Research Center (Neurosciences Institute), Biosanitary Research Institute ibs. GRANADA, University of Granada, Avenida de la Investigación 11, Granada 18016, Spain
| | - Judith Schmidt
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Dirk Schepmann
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Sabrina Pricl
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTS), DEA, University of Trieste, 34127 Trieste, Italy
- Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 90-136 Lodz, Poland
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| |
Collapse
|
4
|
Wang YM, Xia CY, Jia HM, He J, Lian WW, Yan Y, Wang WP, Zhang WK, Xu JK. Sigma-1 receptor: A potential target for the development of antidepressants. Neurochem Int 2022; 159:105390. [PMID: 35810915 DOI: 10.1016/j.neuint.2022.105390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 06/10/2022] [Accepted: 07/05/2022] [Indexed: 10/17/2022]
Abstract
Though a great many of studies on the development of antidepressants for the therapy of major depression disorder (MDD) and the development of antidepressants have been carried out, there still lacks an efficient approach in clinical practice. The involvement of Sigma-1 receptor in the pathological process of MDD has been verified. In this review, recent research focusing on the role of Sigma-1 receptor in the etiology of MDD were summarized. Preclinical studies and clinical trials have found that stress induce the variation of Sigma-1 receptor in the blood, brain and heart. Dysfunction and absence of Sigma-1 receptor result in depressive-like behaviors in rodent animals. Agonists of Sigma-1 receptor show not only antidepressant-like activities but also therapeutical effects in complications of depression. The mechanisms underlying antidepressant-like effects of Sigma-1 receptor may include suppressing neuroinflammation, regulating neurotransmitters, ameliorating brain-derived neurotrophic factor and N-Methyl-D-Aspartate receptor, and alleviating the endoplasmic reticulum stress and mitochondria damage during stress. Therefore, Sigma-1 receptor represents a potential target for antidepressants development.
Collapse
Affiliation(s)
- Yu-Ming Wang
- School of Life Sciences & School of Chinese Medicine Sciences, Beijing University of Chinese Medicine, Beijing, 100029, PR China; Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Cong-Yuan Xia
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Hong-Mei Jia
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, PR China
| | - Jun He
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Wen-Wen Lian
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Yu Yan
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Wen-Ping Wang
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Wei-Ku Zhang
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China.
| | - Jie-Kun Xu
- School of Life Sciences & School of Chinese Medicine Sciences, Beijing University of Chinese Medicine, Beijing, 100029, PR China.
| |
Collapse
|
5
|
Abstract
Positron emission tomography (PET) is useful for noninvasive in vivo visualization of disease-related receptors, for evaluation of receptor occupancy to determine an appropriate drug dosage, and for proof-of-concept of drug candidates in translational research. For these purposes, the specificity of the PET tracer for the target receptor is critical. Here, we review work in this area, focusing on the chemical structures of reported PET tracers, their Ki/Kd values, and the physical properties relevant to target receptor selectivity. Among these physical properties, such as cLogP, cLogD, molecular weight, topological polar surface area, number of hydrogen bond donors, and pKa, we focus especially on LogD and LogP as important physical properties that can be easily compared across a range of studies. We discuss the success of PET tracers in evaluating receptor occupancy and consider likely future developments in the field.
Collapse
Affiliation(s)
- Yuta Takamura
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Hiroki Kakuta
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| |
Collapse
|
6
|
Agha H, McCurdy CR. In vitro and in vivo sigma 1 receptor imaging studies in different disease states. RSC Med Chem 2021; 12:154-177. [PMID: 34046607 PMCID: PMC8127618 DOI: 10.1039/d0md00186d] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/02/2020] [Indexed: 12/11/2022] Open
Abstract
The sigma receptor system has been classified into two distinct subtypes, sigma 1 (σ1R) and sigma 2 (σ2R). Sigma 1 receptors (σ1Rs) are involved in many neurodegenerative diseases and different central nervous system disorders such as Alzheimer's disease, Parkinson's disease, schizophrenia, and drug addiction, and pain. This makes them attractive targets for developing radioligands as tools to gain a better understanding of disease pathophysiology and clinical diagnosis. Over the years, several σ1R radioligands have been developed to image the changes in σ1R distribution and density providing insights into their role in disease development. Moreover, the involvement of both σ1Rs and σ2Rs with cancer make these ligands, especially those that are σ2R selective, great tools for imaging different types of tumors. This review will discuss the principles of molecular imaging using PET and SPECT, known σ1R radioligands and their applications for labelling σ1Rs under different disease conditions. Furthermore, this review will highlight σ1R radioligands that have demonstrated considerable potential as biomarkers, and an opportunity to fulfill the ultimate goal of better healthcare outcomes and improving human health.
Collapse
Affiliation(s)
- Hebaalla Agha
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville FL 32610 USA +(352) 273 7705 +1 (352) 294 8691
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville FL 32610 USA +(352) 273 7705 +1 (352) 294 8691
- UF Translational Drug Development Core, University of Florida Gainesville FL 32610 USA
| |
Collapse
|
7
|
Grachev ID, Meyer PM, Becker GA, Bronzel M, Marsteller D, Pastino G, Voges O, Rabinovich L, Knebel H, Zientek F, Rullmann M, Sattler B, Patt M, Gerhards T, Strauss M, Kluge A, Brust P, Savola JM, Gordon MF, Geva M, Hesse S, Barthel H, Hayden MR, Sabri O. Sigma-1 and dopamine D2/D3 receptor occupancy of pridopidine in healthy volunteers and patients with Huntington disease: a [ 18F] fluspidine and [ 18F] fallypride PET study. Eur J Nucl Med Mol Imaging 2020; 48:1103-1115. [PMID: 32995944 PMCID: PMC8041674 DOI: 10.1007/s00259-020-05030-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/07/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE Pridopidine is an investigational drug for Huntington disease (HD). Pridopidine was originally thought to act as a dopamine stabilizer. However, pridopidine shows highest affinity to the sigma-1 receptor (S1R) and enhances neuroprotection via the S1R in preclinical studies. Using [18F] fluspidine and [18F] fallypride PET, the purpose of this study was to assess in vivo target engagement/receptor occupancy of pridopidine to the S1R and dopamine D2/D3 receptor (D2/D3R) at clinical relevant doses in healthy volunteers (HVs) and as proof-of-concept in a small number of patients with HD. METHODS Using [18F] fluspidine PET (300 MBq, 0-90 min), 11 male HVs (pridopidine 0.5 to 90 mg; six dose groups) and three male patients with HD (pridopidine 90 mg) were investigated twice, without and 2 h after single dose of pridopidine. Using [18F] fallypride PET (200 MBq, 0-210 min), four male HVs were studied without and 2 h following pridopidine administration (90 mg). Receptor occupancy was analyzed by the Lassen plot. RESULTS S1R occupancy as function of pridopidine dose (or plasma concentration) in HVs could be described by a three-parameter Hill equation with a Hill coefficient larger than one. A high degree of S1R occupancy (87% to 91%) was found throughout the brain at pridopidine doses ranging from 22.5 to 90 mg. S1R occupancy was 43% at 1 mg pridopidine. In contrast, at 90 mg pridopidine, the D2/D3R occupancy was only minimal (~ 3%). CONCLUSIONS Our PET findings indicate that at clinically relevant single dose of 90 mg, pridopidine acts as a selective S1R ligand showing near to complete S1R occupancy with negligible occupancy of the D2/D3R. The dose S1R occupancy relationship suggests cooperative binding of pridopidine to the S1R. Our findings provide significant clarification about pridopidine's mechanism of action and support further use of the 45-mg twice-daily dose to achieve full and selective targeting of the S1R in future clinical trials of neurodegenerative disorders. Clinical Trials.gov Identifier: NCT03019289 January 12, 2017; EUDRA-CT-Nr. 2016-001757-41.
Collapse
Affiliation(s)
- Igor D Grachev
- Teva Branded Pharmaceutical Products R&D, Inc, Malvern, PA, 19355, USA.,Guide Pharmaceutical Consulting, LLC, Millstone, NJ, 08535, USA
| | - Philipp M Meyer
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Georg A Becker
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Marcus Bronzel
- ABX-CRO Advanced Pharmaceutical Services Forschungsgesellschaft mbH, Dresden, Germany
| | - Doug Marsteller
- Teva Branded Pharmaceutical Products R&D, Inc, Frazer, PA, 19355, USA
| | - Gina Pastino
- Teva Branded Pharmaceutical Products R&D, Inc, Frazer, PA, 19355, USA
| | - Ole Voges
- ABX-CRO Advanced Pharmaceutical Services Forschungsgesellschaft mbH, Dresden, Germany
| | - Laura Rabinovich
- Teva Branded Pharmaceutical Products R&D, Inc, Frazer, PA, 19355, USA
| | - Helena Knebel
- Teva Branded Pharmaceutical Products R&D, Inc, Frazer, PA, 19355, USA
| | - Franziska Zientek
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Michael Rullmann
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Bernhard Sattler
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Marianne Patt
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Thilo Gerhards
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Maria Strauss
- Department of Psychiatry and Psychotherapy, University of Leipzig Medical Center, Leipzig, Germany
| | - Andreas Kluge
- ABX-CRO Advanced Pharmaceutical Services Forschungsgesellschaft mbH, Dresden, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig, Germany
| | - Juha-Matti Savola
- Teva Branded Pharmaceutical Products R&D, Inc, Frazer, PA, 19355, USA
| | - Mark F Gordon
- Teva Branded Pharmaceutical Products R&D, Inc, Frazer, PA, 19355, USA
| | - Michal Geva
- Prilenia Therapeutics Development Ltd., Herzliya, Israel
| | - Swen Hesse
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Henryk Barthel
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | | | - Osama Sabri
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany.
| |
Collapse
|
8
|
Ahmed H, Wallimann R, Haider A, Hosseini V, Gruber S, Robledo M, Nguyen TAN, Herde AM, Iten I, Keller C, Vogel V, Schibli R, Wünsch B, Mu L, Ametamey SM. Preclinical Development of 18F-OF-NB1 for Imaging GluN2B-Containing N-Methyl-d-Aspartate Receptors and Its Utility as a Biomarker for Amyotrophic Lateral Sclerosis. J Nucl Med 2020; 62:259-265. [PMID: 32737247 DOI: 10.2967/jnumed.120.246785] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/26/2020] [Indexed: 01/05/2023] Open
Abstract
As part of our continuous efforts to develop a suitable 18F-labeled PET radioligand with improved characteristics for imaging the N-methyl-d-aspartate receptors (NMDARs) subtype 2B (GluN1/2B), we investigated in the current work ortho-fluorinated (OF) and meta-fluorinated (MF) analogs of 18F-para-fluorinated (PF)-NB1, a 3-benzazepine-based radiofluorinated probe. Methods: OF-NB1 and MF-NB1 were prepared using a multistep synthesis, and their binding affinities toward GluN2B subunits and selectivity over σ1 receptors (σ1Rs) were determined via competitive binding assays. 18F-OF-NB1 was synthesized via copper-mediated radiofluorination and was evaluated in Wistar rats by in vitro autoradiography, PET imaging, ex vivo biodistribution, metabolite experiments, and receptor occupancy studies using CP-101,606, an established GluN2B antagonist. To determine in vivo selectivity, 18F-OF-NB1 was validated in wild-type and σ1R knock-out mice. Translational relevance was assessed in autoradiographic studies using postmortem human brain tissues from healthy individuals and ALS patients, the results of which were corroborated by immunohistochemistry. Results: The binding affinity values for OF-NB1 and MF-NB1 toward the GluN2B subunits were 10.4 ± 4.7 and 590 ± 36 nM, respectively. For σ1R binding, OF-NB1 and MF-NB1 exhibited inhibition constants of 410 and 2,700 nM, respectively. OF-NB1, which outperformed MF-NB1, was radiolabeled with 18F to afford 18F-OF-NB1 in more than 95% radiochemical purity and molar activities of 192 ± 33 GBq/μmol. In autoradiography experiments, 18F-OF-NB1 displayed a heterogeneous and specific binding in GluN2B subunit-rich brain regions such as the cortex, striatum, hypothalamus, and hippocampus. PET imaging studies in Wistar rats showed a similar heterogeneous uptake, and no brain radiometabolites were detected. A dose-dependent blocking effect was observed with CP-101,606 (0.5-15 mg/kg) and resulted in a 50% receptor occupancy of 8.1 μmol/kg. Postmortem autoradiography results revealed lower expression of the GluN2B subunits in ALS brain tissue sections than in healthy controls, in line with immunohistochemistry results. Conclusion: 18F-OF-NB1 is a highly promising PET probe for imaging the GluN2B subunits of the N-methyl-d-aspartate receptor. It possesses utility for receptor occupancy studies and has potential for PET imaging studies in ALS patients and possibly other brain disorders.
Collapse
Affiliation(s)
- Hazem Ahmed
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Rahel Wallimann
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Ahmed Haider
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Vahid Hosseini
- Laboratory of Applied Mechanobiology, Institute of Translational Medicine, Department of Health Sciences and Technology, ETH Zürich, Zurich, Switzerland
| | - Stefan Gruber
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Marvin Robledo
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Thi A N Nguyen
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | | | - Irina Iten
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Claudia Keller
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Viola Vogel
- Laboratory of Applied Mechanobiology, Institute of Translational Medicine, Department of Health Sciences and Technology, ETH Zürich, Zurich, Switzerland
| | - Roger Schibli
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland.,Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland; and
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Linjing Mu
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland.,Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland; and
| | - Simon M Ametamey
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| |
Collapse
|
9
|
Lepelletier FX, Vandesquille M, Asselin MC, Prenant C, Robinson AC, Mann DMA, Green M, Barnett E, Banister SD, Mottinelli M, Mesangeau C, McCurdy CR, Fricke IB, Jacobs AH, Kassiou M, Boutin H. Evaluation of 18F-IAM6067 as a sigma-1 receptor PET tracer for neurodegeneration in vivo in rodents and in human tissue. Theranostics 2020; 10:7938-7955. [PMID: 32724451 PMCID: PMC7381740 DOI: 10.7150/thno.47585] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/06/2020] [Indexed: 01/30/2023] Open
Abstract
The sigma 1 receptor (S1R) is widely expressed in the CNS and is mainly located on the endoplasmic reticulum. The S1R is involved in the regulation of many neurotransmission systems and, indirectly, in neurodegenerative diseases. The S1R may therefore represent an interesting neuronal biomarker in neurodegenerative diseases such as Parkinson's (PD) or Alzheimer's diseases (AD). Here we present the characterisation of the S1R-specific 18F-labelled tracer 18F-IAM6067 in two animal models and in human brain tissue. Methods: Wistar rats were used for PET-CT imaging (60 min dynamic acquisition) and metabolite analysis (1, 2, 5, 10, 20, 60 min post-injection). To verify in vivo selectivity, haloperidol, BD1047 (S1R ligand), CM398 (S2R ligand) and SB206553 (5HT2B/C antagonist) were administrated for pre-saturation studies. Excitotoxic lesions induced by intra-striatal injection of AMPA were also imaged by 18F-IAM6067 PET-CT to test the sensitivity of the methods in a well-established model of neuronal loss. Tracer brain uptake was also verified by autoradiography in rats and in a mouse model of PD (intrastriatal 6-hydroxydopamine (6-OHDA) unilateral lesion). Finally, human cortical binding was investigated by autoradiography in three groups of subjects (control subjects with Braak ≤2, and AD patients, Braak >2 & ≤4 and Braak >4 stages). Results: We demonstrate that despite rapid peripheral metabolism of 18F-IAM6067, radiolabelled metabolites were hardly detected in brain samples. Brain uptake of 18F-IAM6067 showed differences in S1R anatomical distribution, namely from high to low uptake: pons-raphe, thalamus medio-dorsal, substantia nigra, hypothalamus, cerebellum, cortical areas and striatum. Pre-saturation studies showed 79-90% blockade of the binding in all areas of the brain indicated above except with the 5HT2B/C antagonist SB206553 and S2R ligand CM398 which induced no significant blockade, indicating good specificity of 18F-IAM6067 for S1Rs. No difference between ipsi- and contralateral sides of the brain in the mouse model of PD was detected. AMPA lesion induced a significant 69% decrease in 18F-IAM6067 uptake in the globus pallidus matching the neuronal loss as measured by NeuN, but only a trend to decrease (-16%) in the caudate putamen despite a significant 91% decrease in neuronal count. Moreover, no difference in the human cortical binding was shown between AD groups and controls. Conclusion: This work shows that 18F-IAM6067 is a specific and selective S1R radiotracer. The absence or small changes in S1R detected here in animal models and human tissue warrants further investigations and suggests that S1R might not be the anticipated ideal biomarker for neuronal loss in neurodegenerative diseases such as AD and PD.
Collapse
Affiliation(s)
- François-Xavier Lepelletier
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
| | - Matthias Vandesquille
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
| | - Marie-Claude Asselin
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, School of Health Sciences, Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom
| | - Christian Prenant
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
| | - Andrew C Robinson
- Salford Royal NHS Foundation Trust, Department of Clinical & Cognitive Neurosciences, Clinical Sciences Building, Salford, United Kingdom
| | - David M A Mann
- Salford Royal NHS Foundation Trust, Department of Clinical & Cognitive Neurosciences, Clinical Sciences Building, Salford, United Kingdom
| | - Michael Green
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, School of Health Sciences, Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom
| | - Elizabeth Barnett
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, School of Health Sciences, Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom
| | | | - Marco Mottinelli
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
| | - Christophe Mesangeau
- Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, University, MS 38677, USA
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
- UF Translational Drug Development Core, University of Florida, Gainesville, FL 32610, USA
| | - Inga B Fricke
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU), Münster, Germany
| | - Andreas H. Jacobs
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU), Münster, Germany
- Department of Geriatrics and Neurology, Johanniter Hospital, Bonn, Germany
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, Sydney, Australia
| | - Hervé Boutin
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
| |
Collapse
|
10
|
Toussaint M, Deuther-Conrad W, Kranz M, Fischer S, Ludwig FA, Juratli TA, Patt M, Wünsch B, Schackert G, Sabri O, Brust P. Sigma-1 Receptor Positron Emission Tomography: A New Molecular Imaging Approach Using ( S)-(-)-[ 18F]Fluspidine in Glioblastoma. Molecules 2020; 25:E2170. [PMID: 32384802 PMCID: PMC7248975 DOI: 10.3390/molecules25092170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 04/30/2020] [Accepted: 05/02/2020] [Indexed: 11/16/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most devastating primary brain tumour characterised by infiltrative growth and resistance to therapies. According to recent research, the sigma-1 receptor (sig1R), an endoplasmic reticulum chaperone protein, is involved in signaling pathways assumed to control the proliferation of cancer cells and thus could serve as candidate for molecular characterisation of GBM. To test this hypothesis, we used the clinically applied sig1R-ligand (S)-(-)-[18F]fluspidine in imaging studies in an orthotopic mouse model of GBM (U87-MG) as well as in human GBM tissue. A tumour-specific overexpression of sig1R in the U87-MG model was revealed in vitro by autoradiography. The binding parameters demonstrated target-selective binding according to identical KD values in the tumour area and the contralateral side, but a higher density of sig1R in the tumour. Different kinetic profiles were observed in both areas, with a slower washout in the tumour tissue compared to the contralateral side. The translational relevance of sig1R imaging in oncology is reflected by the autoradiographic detection of tumour-specific expression of sig1R in samples obtained from patients with glioblastoma. Thus, the herein presented data support further research on sig1R in neuro-oncology.
Collapse
Affiliation(s)
- Magali Toussaint
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Research site Leipzig, 04318 Leipzig, Germany; (W.D.-C.); (M.K.); (S.F.); (F.-A.L.); (P.B.)
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Research site Leipzig, 04318 Leipzig, Germany; (W.D.-C.); (M.K.); (S.F.); (F.-A.L.); (P.B.)
| | - Mathias Kranz
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Research site Leipzig, 04318 Leipzig, Germany; (W.D.-C.); (M.K.); (S.F.); (F.-A.L.); (P.B.)
- PET Imaging Center, University Hospital of North Norway (UNN), 9009 Tromsø, Norway
- Nuclear Medicine and Radiation Biology Research Group, The Arctic University of Norway, 9009 Tromsø, Norway
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Research site Leipzig, 04318 Leipzig, Germany; (W.D.-C.); (M.K.); (S.F.); (F.-A.L.); (P.B.)
| | - Friedrich-Alexander Ludwig
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Research site Leipzig, 04318 Leipzig, Germany; (W.D.-C.); (M.K.); (S.F.); (F.-A.L.); (P.B.)
| | - Tareq A. Juratli
- Department of Neurosurgery, Technische Universität Dresden (TUD), University Hospital Carl Gustav Carus, 01307 Dresden, Germany; (T.A.J.); (G.S.)
| | - Marianne Patt
- Department of Nuclear Medicine, University Hospital Leipzig, 04318 Leipzig, Germany; (M.P.); (O.S.)
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, 48149 Münster, Germany;
| | - Gabriele Schackert
- Department of Neurosurgery, Technische Universität Dresden (TUD), University Hospital Carl Gustav Carus, 01307 Dresden, Germany; (T.A.J.); (G.S.)
| | - Osama Sabri
- Department of Nuclear Medicine, University Hospital Leipzig, 04318 Leipzig, Germany; (M.P.); (O.S.)
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Research site Leipzig, 04318 Leipzig, Germany; (W.D.-C.); (M.K.); (S.F.); (F.-A.L.); (P.B.)
| |
Collapse
|
11
|
Bunse P, Schlepphorst C, Glorius F, Kitamura M, Wünsch B. Short and Atom-Economic Enantioselective Synthesis of the σ 1-Receptor Ligands ( S)- and ( R)-Fluspidine-Important Tools for Positron Emission Tomography Studies. J Org Chem 2019; 84:13744-13754. [PMID: 31523971 DOI: 10.1021/acs.joc.9b01882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Aryl bromides 2a and 2b bearing an alkynyl substituent in the o-position reacted with n-butyllithium and 1-benzylpiperidin-4-one in a one-pot Domino reaction to form ester 3 and aldehyde 5, respectively. Enantiomeric alcohols (R)-8 and (S)-8 were obtained by conjugate NaBH4 reduction of α,β-unsaturated ester 3 in the presence of chiral cocomplexes (R,R)-10 and (S,S)-10. Starting from orthoester 2a, the precursors (R)-8 and (S)-8 for the synthesis of fluspidine enantiomers (R)-1/[18F](R)-1 and (S)-1/[18F](S)-1 were obtained in only two reaction steps without additional steps for N-protection in an atom-economic manner in 95.6% ee and 97.2% ee, respectively.
Collapse
Affiliation(s)
- Paul Bunse
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster , Corrensstraße 48 , D-48149 Münster , Germany
| | - Christoph Schlepphorst
- Organisch-Chemisches Institut der Westfälischen Wilhelms-Universität Münster , Corrensstraße 40 , D-48149 Münster , Germany
| | - Frank Glorius
- Organisch-Chemisches Institut der Westfälischen Wilhelms-Universität Münster , Corrensstraße 40 , D-48149 Münster , Germany
| | - Masato Kitamura
- Graduate School of Pharmaceutical Sciences and Research Center for Materials Science , Nagoya University , Chikusa, Nagoya 464-8601 , Japan
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster , Corrensstraße 48 , D-48149 Münster , Germany
- Cells-in-Motion Cluster of Excellence (EXC 1003-CiM) , Westfälische Wilhelms-Universität Münster , D-48149 Münster , Germany
| |
Collapse
|
12
|
Ahmed H, Haider A, Varisco J, Stanković M, Wallimann R, Gruber S, Iten I, Häne S, Müller Herde A, Keller C, Schibli R, Schepmann D, Mu L, Wünsch B, Ametamey SM. Structure–Affinity Relationships of 2,3,4,5-Tetrahydro-1H-3-benzazepine and 6,7,8,9-Tetrahydro-5H-benzo[7]annulen-7-amine Analogues and the Discovery of a Radiofluorinated 2,3,4,5-Tetrahydro-1H-3-benzazepine Congener for Imaging GluN2B Subunit-Containing N-Methyl-d-aspartate Receptors. J Med Chem 2019; 62:9450-9470. [DOI: 10.1021/acs.jmedchem.9b00812] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Hazem Ahmed
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Ahmed Haider
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Jasmine Varisco
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Maja Stanković
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Rahel Wallimann
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Stefan Gruber
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Irina Iten
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Surya Häne
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Adrienne Müller Herde
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Claudia Keller
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Roger Schibli
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
- Department of Nuclear Medicine, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Dirk Schepmann
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstr. 48, 48149 Münster, Germany
| | - Linjing Mu
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
- Department of Nuclear Medicine, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstr. 48, 48149 Münster, Germany
| | - Simon M. Ametamey
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| |
Collapse
|
13
|
Ye J, Wang L, Deuther-Conrad W, Chen Y, Zhang X, Zhang J, Huang Y, Brust P, Jia H. 18 F-Labeled benzylpiperazine derivatives as highly selective ligands for imaging σ 1 receptor with positron emission tomography. J Labelled Comp Radiopharm 2019; 62:425-437. [PMID: 30991462 DOI: 10.1002/jlcr.3738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/04/2019] [Accepted: 04/09/2019] [Indexed: 11/07/2022]
Abstract
We report the design, synthesis, and evaluation of a new series of benzylpiperazine derivatives as selective σ1 receptor ligands. All seven ligands possessed low nanomolar affinity for σ1 receptors (Ki (σ1 ) = 0.31-4.19 nM) and high subtype selectivity (Ki (σ2 )/Ki (σ1 ) = 50-2448). The fluoroethoxy analogues also exhibited high selectivity toward the vesicular acetylcholine transporter (Ki (VAChT)/Ki (σ1 ) = 99-18252). The corresponding radiotracers [18 F]13, [18 F]14, and [18 F]16 with high selectivity (Ki (σ2 )/Ki (σ1 ) > 100, Ki (VAChT)/Ki (σ1 ) > 1000) were prepared in 42% to 55% radiochemical yields (corrected for decay), greater than 99% radiochemical purity (RCP), and molar activity of about 120 GBq/μmol at the end of synthesis (EOS). All three radiotracers showed high initial brain uptake in mouse (8.37-11.48% ID/g at 2 min), which was not affected by pretreatment with cyclosporine A, suggesting that they are not substrates for permeability-glycoprotein (P-gp). Pretreatment with SA4503 or haloperidol resulted in significantly reduced brain uptake (35%-62% decrease at 30 min). In particular, [18 F]16 displayed high brain-to-blood ratios and high in vivo metabolic stability. Although it may not be an optimal neuroimaging agent because of its slow kinetics in the mouse brain, [18 F]16 can serve as a lead compound for further structural modifications to explore new potential radiotracers for σ1 receptors.
Collapse
Affiliation(s)
- Jiajun Ye
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Liang Wang
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Winnie Deuther-Conrad
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | - Yuanyuan Chen
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Xiaojun Zhang
- Nuclear Medicine Department, Chinese PLA General Hospital, Beijing, China
| | - Jinming Zhang
- Nuclear Medicine Department, Chinese PLA General Hospital, Beijing, China
| | - Yiyun Huang
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Peter Brust
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | - Hongmei Jia
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| |
Collapse
|
14
|
Ludwig FA, Fischer S, Houska R, Hoepping A, Deuther-Conrad W, Schepmann D, Patt M, Meyer PM, Hesse S, Becker GA, Zientek FR, Steinbach J, Wünsch B, Sabri O, Brust P. In vitro and in vivo Human Metabolism of ( S)-[ 18F]Fluspidine - A Radioligand for Imaging σ 1 Receptors With Positron Emission Tomography (PET). Front Pharmacol 2019; 10:534. [PMID: 31263411 PMCID: PMC6585474 DOI: 10.3389/fphar.2019.00534] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/29/2019] [Indexed: 12/26/2022] Open
Abstract
(S)-[18F]fluspidine ((S)-[18F]1) has recently been explored for positron emission tomography (PET) imaging of sigma-1 receptors in humans. In the current report, we have used plasma samples of healthy volunteers to investigate the radiometabolites of (S)-[18F]1 and elucidate their structures with LC-MS/MS. For the latter purpose additional in vitro studies were conducted by incubation of (S)-[18F]1 and (S)-1 with human liver microsomes (HLM). In vitro metabolites were characterized by interpretation of MS/MS fragmentation patterns from collision-induced dissociation or by use of reference compounds. Thereby, structures of corresponding radio-HPLC-detected radiometabolites, both in vitro and in vivo (human), could be identified. By incubation with HLM, mainly debenzylation and hydroxylation occurred, beside further mono- and di-oxygenations. The product hydroxylated at the fluoroethyl side chain was glucuronidated. Plasma samples (10, 20, 30 min p.i., n = 5-6), obtained from human subjects receiving 250–300 MBq (S)-[18F]1 showed 97.2, 95.4, and 91.0% of unchanged radioligand, respectively. In urine samples (90 min p.i.) the fraction of unchanged radioligand was only 2.6% and three major radiometabolites were detected. The one with the highest percentage, also found in plasma, matched the glucuronide formed in vitro. Only a small amount of debenzylated metabolite was detected. In conclusion, our metabolic study, in particular the high fractions of unchanged radioligand in plasma, confirms the suitability of (S)-[18F]1 as PET radioligand for sigma-1 receptor imaging.
Collapse
Affiliation(s)
- Friedrich-Alexander Ludwig
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Steffen Fischer
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Richard Houska
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | | | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Dirk Schepmann
- Department of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Marianne Patt
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany
| | - Philipp M Meyer
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany
| | - Swen Hesse
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany.,Integrated Research and Treatment Center (IFB) Adiposity Diseases, Leipzig University, Leipzig, Germany
| | | | - Franziska Ruth Zientek
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany.,Integrated Research and Treatment Center (IFB) Adiposity Diseases, Leipzig University, Leipzig, Germany
| | - Jörg Steinbach
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Bernhard Wünsch
- Department of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| |
Collapse
|
15
|
Molavipordanjani S, Tolmachev V, Hosseinimehr SJ. Basic and practical concepts of radiopharmaceutical purification methods. Drug Discov Today 2018; 24:315-324. [PMID: 30278224 DOI: 10.1016/j.drudis.2018.09.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/16/2018] [Accepted: 09/26/2018] [Indexed: 01/02/2023]
Abstract
The presence of radiochemical impurities in a radiopharmaceutical contributes to an unnecessary radiation burden for the patients or to an undesirable high radioactivity background, which reduces the imaging contrast or therapeutic efficacy. Therefore, if the radiolabeling process results in unsatisfactory radiochemical purity, a purification step is unavoidable. A successful purification process requires a profound knowledge about the radiopharmaceuticals of interest ranging from structural features to susceptibility to different conditions. Most radiopharmaceutical purification methods are based on solid-phase extraction (SPE), high-performance liquid chromatography (HPLC), size exclusion chromatography (SEC), ion-exchange chromatography (IEC), and liquid-liquid extraction (LLE). Here, we discuss the basic and applied concepts of these purifications methods as well as their advantages and limitations.
Collapse
Affiliation(s)
- Sajjad Molavipordanjani
- Department of Radiopharmacy, Faculty of Pharmacy, Pharmaceutical Sciences Research Center, Mazandaran University of Medical Sciences, Sari, Iran; Student Research Committee, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Vladimir Tolmachev
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Seyed Jalal Hosseinimehr
- Department of Radiopharmacy, Faculty of Pharmacy, Pharmaceutical Sciences Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
| |
Collapse
|
16
|
Shen B, Park JH, Hjørnevik T, Cipriano PW, Yoon D, Gulaka PK, Holly D, Behera D, Avery BA, Gambhir SS, McCurdy CR, Biswal S, Chin FT. Radiosynthesis and First-In-Human PET/MRI Evaluation with Clinical-Grade [ 18F]FTC-146. Mol Imaging Biol 2018; 19:779-786. [PMID: 28280965 DOI: 10.1007/s11307-017-1064-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE Sigma-1 receptors (S1Rs) play an important role in many neurological disorders. Simultaneous positron emission tomography (PET)/magnetic resonance imaging (MRI) with S1R radioligands may provide valuable information for diagnosing and guiding treatment for these diseases. Our previously reported S1R radioligand, [18F]FTC-146, demonstrated high affinity for the S1R (K i = 0.0025 nM) and excellent selectivity for the S1R over the sigma-2 receptor (S2Rs; K i = 364 nM) across several species (from mouse to non-human primate). Herein, we report the clinical-grade radiochemistry filed with exploratory Investigational New Drug (eIND) and first-in-human PET/MRI evaluation of [18F]FTC-146. PROCEDURES [18F]FTC-146 is prepared via a direct [18F] fluoride nucleophilic radiolabeling reaction and formulated in 0.9 % NaCl containing no more than 10 % ethanol through sterile filtration. Quality control (QC) was performed based on USP 823 before doses were released for clinical use. The safety and whole body biodistribution of [18F]FTC-146 were evaluated using a simultaneous PET/MR scanner in two representative healthy human subjects. RESULTS [18F]FTC-146 was synthesized with a radiochemical yield of 3.3 ± 0.7 % and specific radioactivity of 8.3 ± 3.3 Ci/μmol (n = 10, decay corrected to EOB). Both radiochemical and chemical purities were >95 %; the prepared doses were stable for 4 h at ambient temperature. All QC test results met specified clinical criteria. The in vivo PET/MRI investigations showed that [18F]FTC-146 rapidly crossed the blood brain barrier and accumulated in S1R-rich regions of the brain. There were also radioactivity distributed in the peripheral organs, i.e., the lungs, spleen, pancreas, and thyroid. Furthermore, insignificant uptake of [18F]FTC-146 was observed in cortical bone and muscle. CONCLUSION A reliable and automated radiosynthesis for providing routine clinical-grade [18F]FTC-146 for human studies was established in a modified GE TRACERlab FXFN. PET/MRI demonstrated the initial tracer biodistribution in humans, and clinical studies investigating different S1R-related diseases are in progress.
Collapse
Affiliation(s)
- Bin Shen
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Jun Hyung Park
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Trine Hjørnevik
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA.,Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.,The Norwegian Medical Cyclotron Centre, Oslo, Norway
| | - Peter W Cipriano
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Daehyun Yoon
- Radiological Sciences Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Praveen K Gulaka
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Dawn Holly
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Deepak Behera
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Bonnie A Avery
- Department of Pharmaceutics, P1-27, University of Florida, Gainesville, FL, 32610, USA
| | - Sanjiv S Gambhir
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA
| | - Sandip Biswal
- Department of Radiology and Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, 300 Pasteur Drive S-068B, Stanford, CA, 94305, USA.
| | - Frederick T Chin
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA.
| |
Collapse
|
17
|
Jia H, Zhang Y, Huang Y. Imaging sigma receptors in the brain: New opportunities for diagnosis of Alzheimer's disease and therapeutic development. Neurosci Lett 2019; 691:3-10. [PMID: 30040970 DOI: 10.1016/j.neulet.2018.07.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 07/09/2018] [Accepted: 07/20/2018] [Indexed: 10/28/2022]
Abstract
The sigma-1 (σ1) receptor is a chaperone protein located on the mitochondria-associated membrane of the endoplasmic reticulum, while the sigma-2 receptor (σ2) is an endoplasmic reticulum-resident membrane protein. Recent evidence indicates that both of these receptors figure prominently in the pathophysiology of Alzheimer's disease (AD) and thus are targets for the development of novel, disease-modifying therapeutic strategies. Radioligand-based molecular imaging technique such as positron emission tomography (PET) imaging is a powerful tool for the investigation of protein target expression and function in living subjects. In this review, we survey the development of PET radioligands for the σ1 or σ2 receptors and assess their potential for human imaging applications. The availability of PET imaging with σ1 or σ2 receptor-specific radioligands in humans will allow the investigation of these receptors in vivo and lead to further understanding of their respective roles in AD pathogenesis and progression. Moreover, PET imaging can be used in target occupancy studies to assess target engagement and correlate receptor occupancy and therapeutic response of σ1 receptor agonists and σ2 receptor antagonists currently in clinical trials. It is expected that neuroimaging of σ1 and σ2 receptors in the brain will shed new light on AD pathophysiology and may provide us with new biomarkers for diagnosis of AD and efficacy monitoring of emerging AD therapeutic strategies.
Collapse
|
18
|
Haider A, Iten I, Ahmed H, Herde AM, Gruber S, Krämer SD, Keller C, Schibli R, Wünsch B, Mu L, Ametamey SM. Identification and Preclinical Evaluation of a Radiofluorinated Benzazepine Derivative for Imaging the GluN2B Subunit of the Ionotropic NMDA Receptor. J Nucl Med 2018; 60:jnumed.118.212134. [PMID: 30030340 PMCID: PMC8833860 DOI: 10.2967/jnumed.118.212134] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/04/2018] [Indexed: 01/06/2023] Open
Abstract
The previously reported carbon-11 labeled GluN2B PET radioligand 11C-Me-NB1 served as a starting point for derivatization and led to the successful development of a radiofluorinated analogue designated (R)-18F-OF-Me-NB1. Given the short physical half-life of 20.3 min for carbon-11, (R)-18F-OF-Me-NB1 with a physical half-life of 109.8 min would allow satellite distribution to nuclear medicine facilities without an on-site cyclotron. Methods: Two fluorinated Me-NB1 derivatives, OF-Me-NB1 and PF-Me-NB1, were synthesized. Upon chiral resolution, the respective enantiomers were radiolabeled with carbon-11 and assessed in a proof-of-concept study by applying in vitro autoradiography on rodent brain sections. Based on the autoradiograms, (R)-OF-Me-NB1 was selected for radiofluorination and preclinical evaluation by ex vivo autoradiography, PET imaging, biodistribution and metabolite studies in Wistar rats. To rule out off-target binding to the σ1 receptor, the brain uptake of (R)-18F-OF-Me-NB1 in wild-type mice was compared with σ1 receptor knock-out mice. Results: Autoradiographic assessment revealed that both enantiomers of 11C-PF-Me-NB1 distributed homogenously across all brain regions on rodent brain sections. In contrast, the two enantiomers of 11C-OF-Me-NB1 exhibited an entirely different behaviour. While (S)-11C-OF-Me-NB1 bound virtually to all brain regions with considerable σ1 receptor binding, (R)-11C-OF-Me-NB1 exhibited high selectivity and specificity for the GluN2B-rich rat forebrain. These findings were confirmed for the radiofluorinated analogue (R)-11C-OF-Me-NB1, which was obtained via copper-mediated radiofluorination in radiochemical yields of 13-25% and molar activities ranging from 61-168 GBq/µmol. PET imaging and biodistribution studies in Wistar rats indicated appropriate pharmacokinetic profile and high in vivo specific binding of (R)-18F-OF-Me-NB1 as revealed by blocking studies with GluN2B-antagonist CP101,606. Off-target binding to the σ1 receptor was excluded by PET imaging with σ1 receptor knock-out mice. Receptor occupancy experiments with CP101,606 revealed a D50-value of 8.3 µmol/kg (intravenous). Conclusion: (R)-18F-OF-Me-NB1 is a promising radiofluorinated probe that exhibits specificity and selectivity for the GluN2B-containing N-methyl-D-aspartate (NMDA) complex and enables in vivo target occupancy studies in rodents.
Collapse
Affiliation(s)
- Ahmed Haider
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Irina Iten
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Hazem Ahmed
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | | | - Stefan Gruber
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | | | - Claudia Keller
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Roger Schibli
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland; and
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Linjing Mu
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland; and
| | - Simon M. Ametamey
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| |
Collapse
|
19
|
Affiliation(s)
- Paul Bunse
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster; Corrensstraße 48 48149 Münster Germany
| | - Ernst-Ulrich Würthwein
- Organisch-Chemisches Institut der Westfälischen Wilhelms-Universität Münster and Center for Multiscale Theory and Computation (CMTC); Corrensstraße 40 48149 Münster Germany
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster; Corrensstraße 48 48149 Münster Germany
- Cells-in-Motion Cluster of Excellence (EXC; Westfälische Wilhelms-Universität Münster; 1003 - CiM) Münster Germany
| |
Collapse
|
20
|
Kranz M, Bergmann R, Kniess T, Belter B, Neuber C, Cai Z, Deng G, Fischer S, Zhou J, Huang Y, Brust P, Deuther-Conrad W, Pietzsch J. Bridging from Brain to Tumor Imaging: (S)-(-)- and (R)-(+)-[ 18F]Fluspidine for Investigation of Sigma-1 Receptors in Tumor-Bearing Mice. Molecules 2018; 23:E702. [PMID: 29558382 PMCID: PMC6017399 DOI: 10.3390/molecules23030702] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 03/12/2018] [Accepted: 03/18/2018] [Indexed: 12/12/2022] Open
Abstract
Sigma-1 receptors (Sig1R) are highly expressed in various human cancer cells and hence imaging of this target with positron emission tomography (PET) can contribute to a better understanding of tumor pathophysiology and support the development of antineoplastic drugs. Two Sig1R-specific radiolabeled enantiomers (S)-(-)- and (R)-(+)-[18F]fluspidine were investigated in several tumor cell lines including melanoma, squamous cell/epidermoid carcinoma, prostate carcinoma, and glioblastoma. Dynamic PET scans were performed in mice to investigate the suitability of both radiotracers for tumor imaging. The Sig1R expression in the respective tumors was confirmed by Western blot. Rather low radiotracer uptake was found in heterotopically (subcutaneously) implanted tumors. Therefore, a brain tumor model (U87-MG) with orthotopic implantation was chosen to investigate the suitability of the two Sig1R radiotracers for brain tumor imaging. High tumor uptake as well as a favorable tumor-to-background ratio was found. These results suggest that Sig1R PET imaging of brain tumors with [18F]fluspidine could be possible. Further studies with this tumor model will be performed to confirm specific binding and the integrity of the blood-brain barrier (BBB).
Collapse
Affiliation(s)
- Mathias Kranz
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany.
- Department of Diagnostic Radiology, PET Center, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Ralf Bergmann
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
| | - Torsten Kniess
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
| | - Birgit Belter
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
| | - Christin Neuber
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
| | - Zhengxin Cai
- Department of Diagnostic Radiology, PET Center, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Gang Deng
- Department of Neurosurgery and Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Steffen Fischer
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany.
| | - Jiangbing Zhou
- Department of Neurosurgery and Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Yiyun Huang
- Department of Diagnostic Radiology, PET Center, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany.
| | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany.
| | - Jens Pietzsch
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
- Technische Universität Dresden, School of Science, Faculty of Chemistry and Food Chemistry, 01062 Dresden, Germany.
| |
Collapse
|
21
|
Fanter L, Schepmann D, Wünsch B. Solid-phase organic synthesis of chiral, non-racemic 1,2,4-trisubstituted 1,4-diazepanes with high σ 1 receptor affinity. Arch Pharm (Weinheim) 2018; 351. [PMID: 29226992 DOI: 10.1002/ardp.201700334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 11/16/2017] [Accepted: 11/21/2017] [Indexed: 11/09/2022]
Abstract
The aim of this work was to transfer the established chiral-pool synthesis of 1,2,4-trisubstituted 1,4-diazepanes in solution on the solid phase. For this purpose, (S)-configured amino acids, (S)-alanine, and (S)-leucine, with a small methyl and a larger isobutyl moiety were attached to the solid support 9 by reductive amination. After five reaction steps on the solid support, the 1,4-diazepanes (S)-19a,b were cleaved off and reductively alkylated to afford the 1,2,4-trisubstituted 1,4-diazepanes (S)-20a and (S)-21b, respectively. Both compounds show high σ1 affinity and selectivity over the σ2 subtype.
Collapse
Affiliation(s)
- Lena Fanter
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Münster, Germany
| | - Dirk Schepmann
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Münster, Germany
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Münster, Germany
- Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms-Universität Münster, Münster, Germany
| |
Collapse
|
22
|
Hjørnevik T, Cipriano PW, Shen B, Park JH, Gulaka P, Holley D, Gandhi H, Yoon D, Mittra ES, Zaharchuk G, Gambhir SS, McCurdy CR, Chin FT, Biswal S. Biodistribution and Radiation Dosimetry of 18F-FTC-146 in Humans. J Nucl Med 2017; 58:2004-2009. [PMID: 28572487 PMCID: PMC6944163 DOI: 10.2967/jnumed.117.192641] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 05/16/2017] [Indexed: 01/27/2023] Open
Abstract
The purpose of this study was to assess safety, biodistribution, and radiation dosimetry in humans for the highly selective σ-1 receptor PET agent 18F-6-(3-fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one (18F-FTC-146). Methods: Ten healthy volunteers (5 women, 5 men; age ± SD, 34.3 ± 6.5 y) were recruited, and written informed consent was obtained from all participants. Series of whole-body PET/MRI examinations were acquired for up to 3 h after injection (357.2 ± 48.8 MBq). Blood samples were collected, and standard vital signs (heart rate, pulse oximetry, and body temperature) were monitored at regular intervals. Regions of interest were delineated, time-activity curves were calculated, and organ uptake and dosimetry were estimated. Results: All subjects tolerated the PET/MRI examination well, and no adverse reactions to 18F-FTC-146 were reported. High accumulation of 18F-FTC-146 was observed in σ-1 receptor-dense organs such as the pancreas and spleen, moderate uptake in the brain and myocardium, and low uptake in bone and muscle. High uptake was also observed in the kidneys and bladder, indicating renal tracer clearance. The effective dose of 18F-FTC-146 was 0.0259 ± 0.0034 mSv/MBq (range, 0.0215-0.0301 mSv/MBq). Conclusion: First-in-human studies with clinical-grade 18F-FTC-146 were successful. Injection of 18F-FTC-146 is safe, and absorbed doses are acceptable. The potential of 18F-FTC-146 as an imaging agent for a variety of neuroinflammatory diseases is currently under investigation.
Collapse
Affiliation(s)
- Trine Hjørnevik
- Department of Radiology, Stanford University, Stanford, California
- Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway
- The Norwegian Medical Cyclotron Centre, Oslo, Norway
| | - Peter W Cipriano
- Department of Radiology, Stanford University, Stanford, California
| | - Bin Shen
- Department of Radiology, Stanford University, Stanford, California
| | - Jun Hyung Park
- Department of Radiology, Stanford University, Stanford, California
| | - Praveen Gulaka
- Department of Radiology, Stanford University, Stanford, California
| | - Dawn Holley
- Department of Radiology, Stanford University, Stanford, California
| | - Harsh Gandhi
- Department of Radiology, Stanford University, Stanford, California
| | - Daehyun Yoon
- Department of Radiology, Stanford University, Stanford, California
| | - Erik S Mittra
- Department of Radiology, Stanford University, Stanford, California
| | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, California
| | - Sanjiv S Gambhir
- Department of Radiology, Stanford University, Stanford, California
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida; and
- UF Translational Drug Development Core, University of Florida, Gainesville, Florida
| | - Frederick T Chin
- Department of Radiology, Stanford University, Stanford, California
| | - Sandip Biswal
- Department of Radiology, Stanford University, Stanford, California
| |
Collapse
|
23
|
Kokornaczyk AK, Schepmann D, Yamaguchi J, Itami K, Laurini E, Fermeglia M, Pricl S, Wünsch B. Thiazole-Based σ 1 Receptor Ligands: Diversity by Late-Stage C-H Arylation of Thiazoles, Structure-Affinity and Selectivity Relationships, and Molecular Interactions. ChemMedChem 2017; 12:1070-1080. [PMID: 28544475 DOI: 10.1002/cmdc.201700166] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/22/2017] [Indexed: 12/25/2022]
Abstract
Spirocyclic thiophene derivatives represent promising σ1 ligands with high σ1 affinity and selectivity over the σ2 subtype. To increase ligand efficiency, the thiophene ring was replaced bioisosterically by a thiazole ring, and the pyran ring was opened. Late-stage diversification by regioselective C-H arylation of thiazoles 9 a-c resulted in a set of 53 compounds with high diversity. This set of compounds was analyzed with respect to σ1 affinity, σ1 /σ2 selectivity, lipophilicity (logD7.4 ), lipophilicity-corrected ligand efficiency (LELP), and molecular target interactions. The most promising candidates were pyridyl-substituted thiazole derivatives 33 c (2-(1-benzyl-4-ethoxypiperidin-4-yl)-5-(pyridin-3-yl)thiazole) and 34 c (2-(1-benzyl-4-ethoxypiperidin-4-yl)-5-(pyridin-4-yl)thiazole), possessing low-nanomolar σ1 affinity (Ki =1.3 and 1.9 nm), high σ1 /σ2 selectivity (>1500-fold), low lipophilicity (logD7.4 =1.8) and very good ligand efficiency (LELP=5.5), indicating promising pharmacodynamics and pharmacokinetics. Molecular simulation studies, including docking and deconvolution of the free binding energy into its major components, led to decreased hydrophobic stabilization of pyridyl derivatives 33 c and 34 c, which was compensated by lower desolvation energy.
Collapse
Affiliation(s)
- Artur K Kokornaczyk
- Institut für Pharmazeutische und Medizinische Chemie der, Universität Münster, Corrensstraße 48, 48149, Münster, Germany
| | - Dirk Schepmann
- Institut für Pharmazeutische und Medizinische Chemie der, Universität Münster, Corrensstraße 48, 48149, Münster, Germany
| | - Junichiro Yamaguchi
- Department of Applied Chemistry, Waseda University, 3-4-1 Ohkubo, Shinjuku, Tokyo 169-8555, Japan
| | - Kenichiro Itami
- Institute of Transformative Bio-Molecules (WPI-ITbM) and Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8602, Japan
| | - Erik Laurini
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), University of Trieste, Via Valerio 6, 34127, Trieste, Italy
- National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Via Valerio 6, 32127, Trieste, Italy
| | - Maurizio Fermeglia
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), University of Trieste, Via Valerio 6, 34127, Trieste, Italy
- National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Via Valerio 6, 32127, Trieste, Italy
| | - Sabrina Pricl
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), University of Trieste, Via Valerio 6, 34127, Trieste, Italy
- National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Via Valerio 6, 32127, Trieste, Italy
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie der, Universität Münster, Corrensstraße 48, 48149, Münster, Germany
- Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms-Universität, Münster, Germany
| |
Collapse
|
24
|
Knappmann I, Lehmkuhl K, Köhler J, Schepmann D, Giera M, Bracher F, Wünsch B. Lipase-catalyzed kinetic resolution as key step in the synthesis of enantiomerically pure σ ligands with 2-benzopyran structure. Bioorg Med Chem 2017; 25:3384-3395. [DOI: 10.1016/j.bmc.2017.04.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 03/31/2017] [Accepted: 04/21/2017] [Indexed: 01/08/2023]
|
25
|
Baum E, Cai Z, Bois F, Holden D, Lin SF, Lara-Jaime T, Kapinos M, Chen Y, Deuther-Conrad W, Fischer S, Dukic-Stefanovic S, Bunse P, Wünsch B, Brust P, Jia H, Huang Y. PET Imaging Evaluation of Four σ 1 Radiotracers in Nonhuman Primates. J Nucl Med 2017; 58:982-988. [PMID: 28232607 DOI: 10.2967/jnumed.116.188052] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/09/2017] [Indexed: 01/24/2023] Open
Abstract
The σ1 receptors (S1Rs) are implicated in a variety of diseases including Alzheimer disease and cancer. Previous PET S1R radiotracers are characterized by slow kinetics or off-target binding that impedes their use in humans. Here, we report the first PET imaging evaluation in rhesus monkeys of 4 18F-labeled spirocyclic piperidine-based PET radiotracers (18F-1 to 18F-4). Methods: Baseline scans for the 4 radiotracers were obtained on an adult male rhesus monkey. Blocking scans were obtained with the S1R-selective agonist SA4503 to assess binding specificity of 18F-2 and 18F-4 Arterial input functions were measured, and binding parameters were determined with kinetic modeling analysis. Results: In the rhesus brain, all 4 radiotracers showed high and fast uptake. Tissue activity washout was rapid for 18F-2 and 18F-4, and much slower for 18F-1 and 18F-3, in line with their respective in vitro S1R-binding affinities. Both the 1-tissue-compartment and multilinear analysis-1 kinetic models provided good fits of time-activity curves and reliable estimates of distribution volume. Regional distribution volume values were highest in the cingulate cortex and lowest in the thalamus for all radiotracers. 18F-4 showed greater differential uptake across brain regions and 3-fold-higher binding potential than 18F-2 SA4503 at the dose of 0.5 mg/kg blocked approximately 85% (18F-2) and 95% (18F-4) of radiotracer binding. Conclusion: Tracers 18F-2 and 18F-4 displayed high brain uptake and fast tissue kinetics, with 18F-4 having higher specific binding signals than 18F-2 in the same monkey. Taken together, these data indicate that both 18F-2 and 18F-4 possess the requisite kinetic and imaging properties as viable PET tracers for imaging S1R in the human brain.
Collapse
Affiliation(s)
- Evan Baum
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Zhengxin Cai
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Frederic Bois
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Daniel Holden
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Shu-Fei Lin
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Teresa Lara-Jaime
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Michael Kapinos
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Yuanyuan Chen
- Ministry of Education Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing, China
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany; and
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany; and
| | - Sladjana Dukic-Stefanovic
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany; and
| | - Paul Bunse
- Department of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Bernhard Wünsch
- Department of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany; and
| | - Hongmei Jia
- Ministry of Education Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing, China
| | - Yiyun Huang
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| |
Collapse
|
26
|
He Y, Xie F, Ye J, Deuther-Conrad W, Cui B, Wang L, Lu J, Steinbach J, Brust P, Huang Y, Lu J, Jia H. 1-(4-[ 18F]Fluorobenzyl)-4-[(tetrahydrofuran-2-yl)methyl]piperazine: A Novel Suitable Radioligand with Low Lipophilicity for Imaging σ 1 Receptors in the Brain. J Med Chem 2017; 60:4161-4172. [PMID: 28409931 DOI: 10.1021/acs.jmedchem.6b01723] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have designed and synthesized novel piperazine compounds with low lipophilicity as σ1 receptor ligands. 1-(4-Fluorobenzyl)-4-[(tetrahydrofuran-2-yl)methyl]piperazine (10) possessed a low nanomolar σ1 receptor affinity and a high selectivity toward the vesicular acetylcholine transporter (>2000-fold), σ2 receptors (52-fold), and adenosine A2A, adrenergic α2, cannabinoid CB1, dopamine D1, D2L, γ-aminobutyric acid A (GABAA), NMDA, melatonin MT1, MT2, and serotonin 5-HT1 receptors. The corresponding radiotracer [18F]10 demonstrated high brain uptake and extremely high brain-to-blood ratios in biodistribution studies in mice. Pretreatment with the selective σ1 receptor agonist SA4503 significantly reduced the level of accumulation of the radiotracer in the brain. No radiometabolite of [18F]10 was observed to enter the brain. Positron emission tomography and magnetic resonance imaging confirmed suitable kinetics and a high specific binding of [18F]10 to σ1 receptors in rat brain. Ex vivo autoradiography showed a reduced level of binding of [18F]10 in the cortex and hippocampus of the senescence-accelerated prone (SAMP8) compared to that of the senescence-accelerated resistant (SAMR1) mice, indicating the potential dysfunction of σ1 receptors in Alzheimer's disease.
Collapse
Affiliation(s)
- Yingfang He
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Fang Xie
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Jiajun Ye
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf , Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, 04318 Leipzig, Germany
| | - Bixiao Cui
- Department of Nuclear Medicine, Xuanwu Hospital Capital Medical University , Beijing, China
| | - Liang Wang
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Jie Lu
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf , Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, 04318 Leipzig, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf , Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, 04318 Leipzig, Germany
| | - Yiyun Huang
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine , New Haven, Connecticut 06520-8048, United States
| | - Jie Lu
- Department of Nuclear Medicine, Xuanwu Hospital Capital Medical University , Beijing, China
| | - Hongmei Jia
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| |
Collapse
|
27
|
Yue X, Jin H, Luo Z, Liu H, Zhang X, McSpadden ED, Tian L, Flores HP, Perlmutter JS, Parsons SM, Tu Z. Chiral resolution of serial potent and selective σ 1 ligands and biological evaluation of (-)-[ 18F]TZ3108 in rodent and the nonhuman primate brain. Bioorg Med Chem 2017; 25:1533-42. [PMID: 28129990 DOI: 10.1016/j.bmc.2017.01.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 11/24/2022]
Abstract
Twelve optically pure enantiomers were obtained using either crystallization or chiral high performance liquid chromatography (HPLC) separation methodologies to resolve six racemic sigma-1 (σ1) receptor ligands. The in vitro binding affinities of each enantiomer for σ1, σ2 receptors and vesicular acetylcholine transporter (VAChT) were determined. Out of the 12 optically pure enantiomers, five displayed very high affinities for σ1 (Ki<2nM) and high selectivity for σ1 versus σ2 and VAChT (>100-fold). The minus enantiomer, (-)-14a ((-)-TZ3108) (Ki-σ1=1.8±0.4nM, Ki-σ2=6960±810nM, Ki-VAChT=980±87nM), was chosen for radiolabeling and further in vivo evaluation in rodents and nonhuman primates (NHPs). A biodistribution study in Sprague Dawley rats showed brain uptake (%ID/gram) of (-)-[18F]TZ3108 reached 1.285±0.062 at 5min and 0.802±0.129 at 120min. NHP microPET imaging studies revealed higher brain uptake of (-)-[18F]TZ3108 and more favorable pharmacokinetics compared to its racemic counterpart. Pretreatment of the animal using two structurally different σ1 ligands significantly decreased accumulation of (-)-[18F]TZ3108 in the brain. Together, our in vivo evaluation results suggest that (-)-[18F]TZ3108 is a promising positron emission tomography (PET) tracer for quantifying σ1 receptor in the brain.
Collapse
|
28
|
Weber F, Brust P, Laurini E, Pricl S, Wünsch B. Fluorinated PET Tracers for Molecular Imaging of σ 1 Receptors in the Central Nervous System. Adv Exp Med Biol 2017; 964:31-48. [PMID: 28315263 DOI: 10.1007/978-3-319-50174-1_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
At first the role of σ1 receptors in various neurological, psychiatric and neurodegenerative disorders is discussed. In the second part, the principle of positron emission tomography (PET ) is described and the known fluorinated PET tracers for labeling of σ1 receptors are presented. The third part focuses on fluoroalkyl substituted spirocyclic PET tracers, which represent the most promising class of fluorinated PET tracers reported so far. The homologous fluoroalkyl derivatives 12-15 show high σ1 affinity (K i = 0.59-1.4 nM) and high selectivity over the σ2 subtype (408-1331-fold). The enantiomers of the fluoroethyl derivative fluspidine 13 were prepared and pharmacologically characterized. Whereas the (S)-configured enantiomer (S)-13 (K i = 2.3 nM) is 4-fold less active than the (R)-enantiomer (R)-13 (K i = 0.57 nM), (S)-13 is metabolically more stable. The interactions of (S)-13 and (R)-13 with the σ1 receptor were analyzed at the molecular level using the 3D homology model. In an automated radiosynthesis [18F](S)-13 and [18F](R)-13 were prepared by nucleophilic substitution of the tosylates (S)-17 and (R)-17 with K[18F]F in high radiochemical yield, high radiochemical purity and short reaction time. Application of both enantiomers [18F](S)-13 and [18F](R)-13 to mice and piglets led to fast uptake into the brain, but [18F](R)-13 did not show washout from the brain indicating a quasi-irreversible binding. Both radiotracers [18F](S)-13 and [18F](R)-13 were able to label regions in the mouse and piglet brain with high σ1 receptor density. The specific binding of the enantiomeric tracers [18F](S)-13 and [18F](R)-13 could be replaced by the selective σ1 ligand SA4503.
Collapse
Affiliation(s)
- Frauke Weber
- Institute of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149, Münster, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, D-04318, Leipzig, Germany
| | - Erik Laurini
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), University of Trieste, Via Valerio 6, 34127, Trieste, Italy
| | - Sabrina Pricl
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), University of Trieste, Via Valerio 6, 34127, Trieste, Italy
- National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Via Valerio 6, 32127, Trieste, Italy
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149, Münster, Germany.
- Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University Münster, Münster, Germany.
| |
Collapse
|
29
|
Weber F, Wünsch B. Medicinal Chemistry of σ 1 Receptor Ligands: Pharmacophore Models, Synthesis, Structure Affinity Relationships, and Pharmacological Applications. Handb Exp Pharmacol 2017; 244:51-79. [PMID: 28620761 DOI: 10.1007/164_2017_33] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
In the first part of this chapter, we summarize the various pharmacophore models for σ1 receptor ligands. Common to all of them is a basic amine flanked by two hydrophobic regions, representing the pharmacophoric elements. The development of computer-based models like the 3D homology model is described as well as the first crystal structure of the σ1 receptor. The second part focuses on the synthesis and biological properties of different σ1 receptor ligands, identified as 1-9. Monocyclic piperazines 1 and bicyclic piperazines 2 and 3 were developed as cytotoxic compounds, thus the IC50 values of cell growth and survival inhibition studies are given for all derivatives. The mechanism of cell survival inhibition, induction of time-dependent apoptosis, of compound ent-2a is discussed. Experimentally determined σ1 affinity shows good correlation with the results from molecular dynamics simulations based on a 3D homology model. Spirocyclic compounds 4 and 5 represent well-established σ1 receptor ligands. The homologous fluoroalkyl derivatives 4 have favorable pharmacological properties for use as fluorinated PET tracers. The (S)-configured fluoroethyl substituted compound (S)-4b is under investigation as PET tracer for imaging of σ1 receptors in the brain of patients affected by major depression. 1,3-Dioxanes 6c and 6d display a very potent σ1 antagonist profile and the racemic 1,3-dioxane 6c has high anti-allodynic activity at low doses. The arylpropenylamines 7 are very potent σ1 receptor ligands with high σ1/σ2 selectivity. The top compound 7g acts as an agonist as defined by its ability to potentiate neurite outgrowth at low concentrations. Among the morpholinoethoxypyrazoles 8, 8c (known as S1RA) reveals the most promising pharmacokinetic and physicochemical properties. Due to its good safety profile, 8c is currently being investigated in a phase II clinical trial for the treatment of neuropathic pain. The most potent ligand 9e of 3,4-dihydro-2(1H)-quinolones 9 shows promising anti-nociceptive activity in the formalin test.
Collapse
Affiliation(s)
- Frauke Weber
- Institute of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstr. 48, Münster, 48149, Germany.
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstr. 48, Münster, 48149, Germany
- Cells-in-Motion Cluster of Excellence (EXC 1003 - CIM), University Münster, Münster, Germany
| |
Collapse
|
30
|
Wiese C, Große Maestrup E, Galla F, Schepmann D, Hiller A, Fischer S, Ludwig FA, Deuther-Conrad W, Donat CK, Brust P, Büter L, Karst U, Wünsch B. Comparison of in Silico, Electrochemical, in Vitro and in Vivo Metabolism of a Homologous Series of (Radio)fluorinated σ 1 Receptor Ligands Designed for Positron Emission Tomography. ChemMedChem 2016; 11:2445-2458. [PMID: 27677767 DOI: 10.1002/cmdc.201600366] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/29/2016] [Indexed: 11/05/2022]
Abstract
The imaging of σ1 receptors in the brain by fluorinated radiotracers will be used for the validation of σ1 receptors as drug targets as well as for differential diagnosis of diseases in the central nervous system. The biotransformation of four homologous fluorinated PET tracers 1'-benzyl-3-(ω-fluoromethyl to ω-fluorobutyl)-3H-spiro[2]benzofuran-1,4'-piperidine] ([18 F]1-4) was investigated. In silico studies using fast metabolizer (FAME) software, electrochemical oxidations, in vitro studies with rat liver microsomes, and in vivo metabolism studies after application of the PET tracers [18 F]1-4 to mice were performed. Combined liquid chromatography and mass spectrometry (HPLC-MS) analysis allowed structural identification of non-radioactive metabolites. Radio-HPLC and radio-TLC provided information about the presence of unchanged parent radiotracers and their radiometabolites. Radiometabolites were not found in the brain after application of [18 F]2-4, but liver, plasma, and urine samples contained several radiometabolites. Less than 2 % of the injected dose of [18 F]4 reached the brain, rendering [18 F]4 less appropriate as a PET tracer than [18 F]2 and [18 F]3. Compounds [18 F]2 and [18 F]3 possess the most promising properties for imaging of σ1 receptors in the brain. High σ1 affinity (Ki =0.59 nm), low lipophilicity (logD7.4 =2.57), high brain penetration (4.6 % of injected dose after 30 min), and the absence of radiometabolites in the brain favor the fluoroethyl derivative [18 F]2 slightly over the fluoropropyl derivative [18 F]3 for human use.
Collapse
Affiliation(s)
- Christian Wiese
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany
| | - Eva Große Maestrup
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany
| | - Fabian Galla
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany
| | - Dirk Schepmann
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany
| | - Achim Hiller
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Permoserstraße 15, 04318, Leipzig, Germany
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Permoserstraße 15, 04318, Leipzig, Germany
| | - Friedrich-Alexander Ludwig
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Permoserstraße 15, 04318, Leipzig, Germany
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Permoserstraße 15, 04318, Leipzig, Germany
| | - Cornelius K Donat
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Permoserstraße 15, 04318, Leipzig, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Permoserstraße 15, 04318, Leipzig, Germany
| | - Lars Büter
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 30, 48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 100-CiM), Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
| | - Uwe Karst
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 30, 48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 100-CiM), Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 100-CiM), Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
| |
Collapse
|
31
|
Kranz M, Sattler B, Wüst N, Deuther-Conrad W, Patt M, Meyer PM, Fischer S, Donat CK, Wünsch B, Hesse S, Steinbach J, Brust P, Sabri O. Evaluation of the Enantiomer Specific Biokinetics and Radiation Doses of [(18)F]Fluspidine-A New Tracer in Clinical Translation for Imaging of σ₁ Receptors. Molecules 2016; 21:E1164. [PMID: 27598110 PMCID: PMC6273209 DOI: 10.3390/molecules21091164] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 08/22/2016] [Accepted: 08/26/2016] [Indexed: 11/17/2022] Open
Abstract
The enantiomers of [(18)F]fluspidine, recently developed for imaging of σ₁ receptors, possess distinct pharmacokinetics facilitating their use in different clinical settings. To support their translational potential, we estimated the human radiation dose of (S)-(-)-[(18)F]fluspidine and (R)-(+)-[(18)F]fluspidine from ex vivo biodistribution and PET/MRI data in mice after extrapolation to the human scale. In addition, we validated the preclinical results by performing a first-in-human PET/CT study using (S)-(-)-[(18)F]fluspidine. Based on the respective time-activity curves, we calculated using OLINDA the particular organ doses (ODs) and effective doses (EDs). The ED values of (S)-(-)-[(18)F]fluspidine and (R)-(+)-[(18)F]fluspidine differed significantly with image-derived values obtained in mice with 12.9 μSv/MBq and 14.0 μSv/MBq (p < 0.025), respectively. A comparable ratio was estimated from the biodistribution data. In the human study, the ED of (S)-(-)-[(18)F]fluspidine was calculated as 21.0 μSv/MBq. Altogether, the ED values for both [(18)F]fluspidine enantiomers determined from the preclinical studies are comparable with other (18)F-labeled PET imaging agents. In addition, the first-in-human study confirmed that the radiation risk of (S)-(-)-[(18)F]fluspidine imaging is within acceptable limits. However, as already shown for other PET tracers, the actual ED of (S)-(-)-[(18)F]fluspidine in humans was underestimated by preclinical imaging which needs to be considered in other first-in-human studies.
Collapse
Affiliation(s)
- Mathias Kranz
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Bernhard Sattler
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Nathanael Wüst
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Marianne Patt
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Philipp M Meyer
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Cornelius K Donat
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
- Division of Brain Sciences, Department of Medicine, Hammersmith Hospital Campus, Imperial College London, London SW7 2AZ, UK.
| | - Bernhard Wünsch
- Pharmaceutical and Medicinal Chemistry, University Münster, Münster 48149, Germany.
| | - Swen Hesse
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, University Hospital Leipzig, Leipzig 04103, Germany.
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Leipzig 04318, Germany.
| | - Osama Sabri
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig 04103, Germany.
| |
Collapse
|
32
|
Knappmann I, Schepmann D, Wünsch B. Oxa-Pictet–Spengler reaction as key step in the synthesis of novel σ receptor ligands with 2-benzopyran structure. Bioorg Med Chem 2016; 24:4045-55. [DOI: 10.1016/j.bmc.2016.06.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/17/2016] [Accepted: 06/23/2016] [Indexed: 01/09/2023]
|
33
|
Ye J, Wang X, Deuther-Conrad W, Zhang J, Li J, Zhang X, Wang L, Steinbach J, Brust P, Jia H. Synthesis and evaluation of a18F-labeled 4-phenylpiperidine-4-carbonitrile radioligand for σ1receptor imaging. J Labelled Comp Radiopharm 2016; 59:332-9. [DOI: 10.1002/jlcr.3408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 03/10/2016] [Accepted: 05/03/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Jiajun Ye
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry; Beijing Normal University; Beijing 100875 China
| | - Xia Wang
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry; Beijing Normal University; Beijing 100875 China
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Department of Neuroradiopharmaceuticals; Institute of Radiopharmaceutical Cancer Research; 04318 Leipzig Germany
| | - Jinming Zhang
- Nuclear Medicine Department; Chinese PLA General Hospital; Beijing 100853 China
| | - Jianzhou Li
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry; Beijing Normal University; Beijing 100875 China
| | - Xiaojun Zhang
- Nuclear Medicine Department; Chinese PLA General Hospital; Beijing 100853 China
| | - Liang Wang
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry; Beijing Normal University; Beijing 100875 China
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf, Department of Neuroradiopharmaceuticals; Institute of Radiopharmaceutical Cancer Research; 04318 Leipzig Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Department of Neuroradiopharmaceuticals; Institute of Radiopharmaceutical Cancer Research; 04318 Leipzig Germany
| | - Hongmei Jia
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry; Beijing Normal University; Beijing 100875 China
| |
Collapse
|
34
|
|
35
|
van Waarde A, Rybczynska AA, Ramakrishnan NK, Ishiwata K, Elsinga PH, Dierckx RAJO. Potential applications for sigma receptor ligands in cancer diagnosis and therapy. Biochim Biophys Acta 2015; 1848:2703-14. [PMID: 25173780 DOI: 10.1016/j.bbamem.2014.08.022] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/04/2014] [Accepted: 08/19/2014] [Indexed: 01/03/2023]
Abstract
Sigma receptors (sigma-1 and sigma-2) represent two independent classes of proteins. Their endogenous ligands may include the hallucinogen N,N-dimethyltryptamine (DMT) and sphingolipid-derived amines which interact with sigma-1 receptors, besides steroid hormones (e.g., progesterone) which bind to both sigma receptor subpopulations. The sigma-1 receptor is a ligand-regulated molecular chaperone with various ion channels and G-protein-coupled membrane receptors as clients. The sigma-2 receptor was identified as the progesterone receptor membrane component 1 (PGRMC1). Although sigma receptors are over-expressed in tumors and up-regulated in rapidly dividing normal tissue, their ligands induce significant cell death only in tumor tissue. Sigma ligands may therefore be used to selectively eradicate tumors. Multiple mechanisms appear to underlie cell killing after administration of sigma ligands, and the signaling pathways are dependent both on the type of ligand and the type of tumor cell. Recent evidence suggests that the sigma-2 receptor is a potential tumor and serum biomarker for human lung cancer and an important target for inhibiting tumor invasion and cancer progression. Current radiochemical efforts are focused on the development of subtype-selective radioligands for positron emission tomography (PET) imaging. Right now, the mostpromising tracers are [18F]fluspidine and [18F]FTC-146 for sigma-1 receptors and [11C]RHM-1 and [18F]ISO-1 for the sigma-2 subtype. Nanoparticles coupled to sigma ligands have shown considerable potential for targeted delivery of antitumor drugs in animal models of cancer, but clinical studies exploring this strategy in cancer patients have not yet been reported. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
Collapse
Affiliation(s)
- Aren van Waarde
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
| | - Anna A Rybczynska
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Nisha K Ramakrishnan
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Kiichi Ishiwata
- Tokyo Metropolitan Institute of Gerontology, Research Team for Neuroimaging, 35-2 Sakae-Cho, Itabashi-Ku, Tokyo 173-0015, Japan
| | - Philip H Elsinga
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Rudi A J O Dierckx
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Hanzeplein 1, 9713 GZ Groningen, The Netherlands; University of Ghent, University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| |
Collapse
|
36
|
Shen B, James ML, Andrews L, Lau C, Chen S, Palner M, Miao Z, Arksey NC, Shuhendler AJ, Scatliffe S, Kaneshige K, Parsons SM, McCurdy CR, Salehi A, Gambhir SS, Chin FT. Further validation to support clinical translation of [(18)F]FTC-146 for imaging sigma-1 receptors. EJNMMI Res 2015; 5:49. [PMID: 26384292 DOI: 10.1186/s13550-015-0122-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This study aims to further evaluate the specificity and selectivity of [(18)F]FTC-146 and obtain additional data to support its clinical translation. METHODS The binding of [(19)F]FTC-146 to vesicular acetylcholine transporter (VAChT) was evaluated using [(3)H]vesamicol and PC12(A123.7) cells in an in vitro binding assay. The uptake and kinetics of [(18)F]FTC-146 in S1R-knockout mice (S1R-KO) compared to wild-type (WT) littermates was assessed using dynamic positron emission tomography (PET) imaging. Ex vivo autoradiography and histology were conducted using a separate cohort of S1R-KO/WT mice, and radiation dosimetry was calculated from WT mouse data (extrapolated for human dosing). Toxicity studies in Sprague-Dawley rats were performed with a dose equivalent to 250× the anticipated clinical dose of [(19)F]FTC-146 mass. RESULTS AND DISCUSSION VAChT binding assay results verified that [(19)F]FTC-146 displays negligible affinity for VAChT (K i = 450 ± 80 nM) compared to S1R. PET images demonstrated significantly higher tracer uptake in WT vs. S1R-KO brain (4.57 ± 1.07 vs. 1.34 ± 0.4 %ID/g at 20-25 min, n = 4, p < 0.05). In S1R-KO mice, it was shown that rapid brain uptake and clearance 10 min post-injection, which are consistent with previous S1R-blocking studies in mice. Three- to fourfold higher tracer uptake was observed in WT relative to S1R-KO mouse brains by ex vivo autoradiography. S1R staining coincided well with the autoradiographic data in all examined brain regions (r (2) = 0.85-0.95). Biodistribution results further demonstrated high [(18)F]FTC-146 accumulation in WT relative to KO mouse brain and provided quantitative information concerning tracer uptake in S1R-rich organs (e.g., heart, lung, pancreas) for WT mice vs. age-matched S1R-KO mice. The maximum allowed dose per scan in humans as extrapolated from mouse dosimetry was 33.19 mCi (1228.03 MBq). No significant toxicity was observed even at a 250X dose of the maximum carrier mass [(19)F]FTC-146 expected to be injected for human studies. CONCLUSIONS Together, these data indicate that [(18)F]FTC-146 binds specifically to S1Rs and is a highly promising radiotracer ready for clinical translation to investigate S1R-related diseases.
Collapse
|
37
|
Xie F, Bergmann R, Kniess T, Deuther-Conrad W, Mamat C, Neuber C, Liu B, Steinbach J, Brust P, Pietzsch J, Jia H. (18)F-Labeled 1,4-Dioxa-8-azaspiro[4.5]decane Derivative: Synthesis and Biological Evaluation of a σ1 Receptor Radioligand with Low Lipophilicity as Potent Tumor Imaging Agent. J Med Chem 2015; 58:5395-407. [PMID: 26090686 DOI: 10.1021/acs.jmedchem.5b00593] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We report the syntheses and evaluation of series of novel piperidine compounds with low lipophilicity as σ1 receptor ligands. 8-(4-(2-Fluoroethoxy)benzyl)-1,4-dioxa-8-azaspiro[4.5]decane (5a) possessed high affinity (K(i) = 5.4 ± 0.4 nM) for σ1 receptors and selectivity for σ2 receptors (30-fold) and the vesicular acetylcholine transporter (1404-fold). [(18)F]5a was prepared using a one-pot, two-step labeling procedure in an automated synthesis module, with a radiochemical purity of >95%, and a specific activity of 25-45 GBq/μmol. Cellular association, biodistribution, and autoradiography with blocking experiments indicated specific binding of [(18)F]5a to σ1 receptors in vitro and in vivo. Small animal positron emission tomography (PET) imaging using mouse tumor xenograft models demonstrated a high accumulation in human carcinoma and melanoma. Treatment with haloperidol significantly reduced the accumulation of the radiotracer in tumors. These findings suggest that radiotracer with suitable lipophilicity and appropriate affinity for σ1 receptors could be used for tumor imaging.
Collapse
Affiliation(s)
- Fang Xie
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany.,‡Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ralf Bergmann
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Torsten Kniess
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Winnie Deuther-Conrad
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Constantin Mamat
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany.,§Technische Universität Dresden, Department of Chemistry and Food Chemistry, D-01062 Dresden, Germany
| | - Christin Neuber
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Boli Liu
- ‡Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Jörg Steinbach
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany.,§Technische Universität Dresden, Department of Chemistry and Food Chemistry, D-01062 Dresden, Germany
| | - Peter Brust
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Jens Pietzsch
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany.,§Technische Universität Dresden, Department of Chemistry and Food Chemistry, D-01062 Dresden, Germany
| | - Hongmei Jia
- ‡Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| |
Collapse
|
38
|
Radadiya A, Shah A. Bioactive benzofuran derivatives: An insight on lead developments, radioligands and advances of the last decade. Eur J Med Chem 2015; 97:356-76. [PMID: 25703339 DOI: 10.1016/j.ejmech.2015.01.021] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 12/19/2014] [Accepted: 01/10/2015] [Indexed: 02/08/2023]
Abstract
Benzofuran core is a highly versatile, presents in many important natural products and natural drugs. Many benzofuran containing synthetic drugs and clinical candidates have been derived from natural products. The present review will provide an insight on lead design-developments of the decade, clinical candidates and PET tracer radio-ligands containing benzofuran core along with brief target biology. Brief of the all approved drugs containing benzofuran core also have been enclosed. Main therapeutic areas covered are Cancer, Neurological disorders including anti-psychotic agent and diabetes.
Collapse
|
39
|
Chen YY, Wang X, Zhang JM, Deuther-Conrad W, Zhang XJ, Huang Y, Li Y, Ye JJ, Cui MC, Steinbach J, Brust P, Liu BL, Jia HM. Synthesis and evaluation of a 18F-labeled spirocyclic piperidine derivative as promising σ1 receptor imaging agent. Bioorg Med Chem 2014; 22:5270-8. [DOI: 10.1016/j.bmc.2014.08.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/18/2014] [Accepted: 08/05/2014] [Indexed: 12/16/2022]
|
40
|
Brust P, van den Hoff J, Steinbach J. Development of (18)F-labeled radiotracers for neuroreceptor imaging with positron emission tomography. Neurosci Bull 2014; 30:777-811. [PMID: 25172118 DOI: 10.1007/s12264-014-1460-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 06/02/2014] [Indexed: 12/14/2022] Open
Abstract
Positron emission tomography (PET) is an in vivo molecular imaging tool which is widely used in nuclear medicine for early diagnosis and treatment follow-up of many brain diseases. PET uses biomolecules as probes which are labeled with radionuclides of short half-lives, synthesized prior to the imaging studies. These probes are called radiotracers. Fluorine-18 is a radionuclide routinely used in the radiolabeling of neuroreceptor ligands for PET because of its favorable half-life of 109.8 min. The delivery of such radiotracers into the brain provides images of transport, metabolic, and neurotransmission processes on the molecular level. After a short introduction into the principles of PET, this review mainly focuses on the strategy of radiotracer development bridging from basic science to biomedical application. Successful radiotracer design as described here provides molecular probes which not only are useful for imaging of human brain diseases, but also allow molecular neuroreceptor imaging studies in various small-animal models of disease, including genetically-engineered animals. Furthermore, they provide a powerful tool for in vivo pharmacology during the process of pre-clinical drug development to identify new drug targets, to investigate pathophysiology, to discover potential drug candidates, and to evaluate the pharmacokinetics and pharmacodynamics of drugs in vivo.
Collapse
|
41
|
Brust P, Deuther-Conrad W, Becker G, Patt M, Donat CK, Stittsworth S, Fischer S, Hiller A, Wenzel B, Dukic-Stefanovic S, Hesse S, Steinbach J, Wünsch B, Lever SZ, Sabri O. Distinctive in vivo kinetics of the new σ1 receptor ligands (R)-(+)- and (S)-(-)-18F-fluspidine in porcine brain. J Nucl Med 2014; 55:1730-6. [PMID: 25071097 DOI: 10.2967/jnumed.114.137562] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Because of their involvement in growth and survival signaling cascades, the σ(1) receptors (σ(1)Rs) represent a novel target for the treatment of cancer and several brain diseases such as depression and neurodegeneration. From a series of σ1R-specific (18)F-fluoroalkylated spirocyclic piperidines, we have chosen (18)F-fluspidine for detailed investigation of the in vivo kinetics of the (R)-(+)- and (S)-(-)-enantiomers to identify their potential for imaging in humans. METHODS Enantiopure tosylate precursors for radiolabeling were obtained using chiral preparative high-performance liquid chromatography and used for radiosynthesis of both (18)F-fluspidine enantiomers by nucleophilic substitution with K-(18)F-F-Kryptofix 222-carbonate complex in a synthesis module. Brain pharmacokinetics were investigated by dynamic PET studies in piglets under baseline and blocking conditions using the highly selective σ1R agonist SA4503. Standardized uptake values (SUVs) were calculated for 24 MR-defined brain regions. Total distribution volume (V(T)) and binding potentials (k3'/k4) of (S)-(-)- and (R)-(+)-(18)F-fluspidine were estimated. Furthermore, V(T) values were estimated by graphical analysis using Logan plots. RESULTS The (S)- and (R)-tosylates were obtained in excellent enantiomeric purities (>98% and >96% enantiomeric excess, respectively). (S)-(-)- and (R)-(+)-(18)F-fluspidine were synthesized within approximately 70 min (radiochemical yield, 35%-45%; specific activity, 650-870 GBq/μmol; radiochemical purity, >99%). Both radiotracers displayed different brain uptake kinetics. Although the initial brain uptake was similar, the SUV at the end of the study differed significantly (P < 0.05), with (R)-(+)-(18)F-fluspidine showing about 60%-150% higher values. Administration of SA4503 reduced SUV almost equally for both radiotracers by approximately 65%. Furthermore, k(3)' was significantly decreased under blocking conditions in almost all regions ((S)-(-)-(18)F-fluspidine, -90%-95%; (R)-(+)-(18)F-fluspidine, -70%-90%) whereas effects on k(4) differed according to the particular brain region. V(T) estimated by both graphical analysis using Logan plots and full nonlinear kinetic analysis revealed significant inhibition for both radiotracers under blocking conditions. CONCLUSION Both (S)-(-)- and (R)-(+)-(18)F-fluspidine appear to be suitable for σ1R imaging in humans. The different pharmacokinetics of (S)-(-)-(18)F-fluspidine and (R)-(+)-(18)F-fluspidine may have the potential for application in the diagnostics of different pathologic conditions.
Collapse
Affiliation(s)
- Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Georg Becker
- Department of Nuclear Medicine and IFB Adiposity Diseases, Universität Leipzig, Leipzig, Germany
| | - Marianne Patt
- Department of Nuclear Medicine and IFB Adiposity Diseases, Universität Leipzig, Leipzig, Germany
| | - Cornelius K Donat
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | | | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Achim Hiller
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Barbara Wenzel
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Sladjana Dukic-Stefanovic
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Swen Hesse
- Department of Nuclear Medicine and IFB Adiposity Diseases, Universität Leipzig, Leipzig, Germany
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Bernhard Wünsch
- Department of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany; and
| | - Susan Z Lever
- Department of Chemistry, University of Missouri, Columbia, Missouri MU Research Reactor, University of Missouri, Columbia, Missouri
| | - Osama Sabri
- Department of Nuclear Medicine and IFB Adiposity Diseases, Universität Leipzig, Leipzig, Germany
| |
Collapse
|
42
|
Banister SD, Manoli M, Kassiou M. The development of radiotracers for imaging sigma (σ) receptors in the central nervous system (CNS) using positron emission tomography (PET). J Labelled Comp Radiopharm 2014; 56:215-24. [PMID: 24285328 DOI: 10.1002/jlcr.3010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 11/19/2012] [Accepted: 11/20/2012] [Indexed: 11/10/2022]
Abstract
Sigma (σ) receptors are unique mammalian proteins, distributed in the central nervous system and elsewhere, which are increasingly implicated in the pathophysiology of virtually all major central nervous system disorders. The heterogeneous but wide distribution of σ1 in the brain has prompted the development of selective radiotracers for imaging these sites using positron emission tomography (PET). To date, some 50 carbon-11-labelled and fluorine-18-labelled candidate PET radioligands targeting σ receptors have been reported. The historical development of selective σ1 receptor ligands as potential PET imaging agents, as well as the radiochemistry and application of the most recently developed examples, is described herein.
Collapse
Affiliation(s)
- Samuel D Banister
- Brain and Mind Research Institute, The University of Sydney, NSW, 2050, Australia; School of Chemistry, The University of Sydney, NSW, 2006, Australia
| | | | | |
Collapse
|
43
|
Holl K, Schepmann D, Daniliuc CG, Wünsch B. Sharpless asymmetric dihydroxylation as the key step in the enantioselective synthesis of spirocyclic σ1 receptor ligands. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.tetasy.2013.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
44
|
Maisonial-Besset A, Funke U, Wenzel B, Fischer S, Holl K, Wünsch B, Steinbach J, Brust P. Automation of the radiosynthesis and purification procedures for [18F]Fluspidine preparation, a new radiotracer for clinical investigations in PET imaging of σ1 receptors in brain. Appl Radiat Isot 2014; 84:1-7. [DOI: 10.1016/j.apradiso.2013.10.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/05/2013] [Accepted: 10/26/2013] [Indexed: 10/26/2022]
|
45
|
Holl K, Schepmann D, Fischer S, Ludwig FA, Hiller A, Donat CK, Deuther-Conrad W, Brust P, Wünsch B. Asymmetric Synthesis of Spirocyclic 2-Benzopyrans for Positron Emission Tomography of σ1 Receptors in the Brain. Pharmaceuticals (Basel) 2014; 7:78-112. [PMID: 24451404 PMCID: PMC3915196 DOI: 10.3390/ph7010078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/15/2014] [Accepted: 01/16/2014] [Indexed: 11/16/2022] Open
Abstract
Sharpless asymmetric dihydroxylation of styrene derivative 6 afforded chiral triols (R)-7 and (S)-7, which were cyclized with tosyl chloride in the presence of Bu2SnO to provide 2-benzopyrans (R)-4 and (S)-4 with high regioselectivity. The additional hydroxy moiety in the 4-position was exploited for the introduction of various substituents. Williamson ether synthesis and replacement of the Boc protective group with a benzyl moiety led to potent σ1 ligands with high σ1/σ2-selectivity. With exception of the ethoxy derivative 16, the (R)-configured enantiomers represent eutomers with eudismic ratios of up to 29 for the ester (R)-18. The methyl ether (R)-15 represents the most potent σ1 ligand of this series of compounds, with a Ki value of 1.2 nM and an eudismic ratio of 7. Tosylate (R)-21 was used as precursor for the radiosynthesis of [18F]-(R)-20, which was available by nucleophilic substitution with K[18F]F K222 carbonate complex. The radiochemical yield of [18F]-(R)-20 was 18%–20%, the radiochemical purity greater than 97% and the specific radioactivity 175–300 GBq/µmol. Although radiometabolites were detected in plasma, urine and liver samples, radiometabolites were not found in brain samples. After 30 min, the uptake of the radiotracer in the brain was 3.4% of injected dose per gram of tissue and could be reduced by coadministration of the σ1 antagonist haloperidol. [18F]-(R)-20 was able to label those regions of the brain, which were reported to have high density of σ1 receptors.
Collapse
Affiliation(s)
- Katharina Holl
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster, Corrensstraße 48, Münster D-48149, Germany
| | - Dirk Schepmann
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster, Corrensstraße 48, Münster D-48149, Germany
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Abteilung Neuroradiopharmaka, Permoserstraße 15, Leipzig D-04318, Germany
| | - Friedrich-Alexander Ludwig
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Abteilung Neuroradiopharmaka, Permoserstraße 15, Leipzig D-04318, Germany
| | - Achim Hiller
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Abteilung Neuroradiopharmaka, Permoserstraße 15, Leipzig D-04318, Germany
| | - Cornelius K Donat
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Abteilung Neuroradiopharmaka, Permoserstraße 15, Leipzig D-04318, Germany
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Abteilung Neuroradiopharmaka, Permoserstraße 15, Leipzig D-04318, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Forschungsstelle Leipzig, Abteilung Neuroradiopharmaka, Permoserstraße 15, Leipzig D-04318, Germany
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster, Corrensstraße 48, Münster D-48149, Germany.
| |
Collapse
|
46
|
James ML, Shen B, Nielsen CH, Behera D, Buckmaster CL, Mesangeau C, Zavaleta C, Vuppala PK, Jamalapuram S, Avery BA, Lyons DM, McCurdy CR, Biswal S, Gambhir SS, Chin FT. Evaluation of σ-1 receptor radioligand 18F-FTC-146 in rats and squirrel monkeys using PET. J Nucl Med 2014; 55:147-53. [PMID: 24337599 PMCID: PMC4170105 DOI: 10.2967/jnumed.113.120261] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The noninvasive imaging of σ-1 receptors (S1Rs) could provide insight into their role in different diseases and lead to novel diagnostic/treatment strategies. The main objective of this study was to assess the S1R radiotracer (18)F-FTC-146 in rats. Preliminary squirrel monkey imaging and human serum/liver microsome studies were performed to gain information about the potential of (18)F-FTC-146 for eventual clinical translation. METHODS The distribution and stability of (18)F-FTC-146 in rats were assessed via PET/CT, autoradiography, γ counting, and high-performance liquid chromatography (HPLC). Preliminary PET/MRI of squirrel monkey brain was conducted along with HPLC assessment of (18)F-FTC-146 stability in monkey plasma and human serum. RESULTS Biodistribution studies showed that (18)F-FTC-146 accumulated in S1R-rich rat organs, including the lungs, pancreas, spleen, and brain. Pretreatment with known S1R compounds, haloperidol, or BD1047, before radioligand administration, significantly attenuated (18)F-FTC-146 accumulation in all rat brain regions by approximately 85% (P < 0.001), suggesting radiotracer specificity for S1Rs. Similarly, PET/CT and autoradiography results demonstrated accumulation of (18)F-FTC-146 in rat brain regions known to contain S1Rs and that this uptake could be blocked by BD1047 pretreatment. Ex vivo analysis of (18)F-FTC-146 in the brain showed that only intact radiotracer was present at 15, 30, and 60 min, whereas rapid metabolism of residual (18)F-FTC-146 was observed in rat plasma. Preliminary monkey PET/MRI studies demonstrated specific accumulation of (18)F-FTC-146 in the brain (mainly in cortical structures, cerebellum, and vermis) that could be attenuated by pretreatment with haloperidol. HPLC of monkey plasma suggested radioligand metabolism, whereas (18)F-FTC-146 appeared to be stable in human serum. Finally, liver microsome studies revealed that (18)F-FTC-146 has a longer half-life in human microsomes, compared with rodents. CONCLUSION Together, these results indicate that (18)F-FTC-146 is a promising tool for visualizing S1Rs in preclinical studies and that it has potential for mapping these sites in the human brain.
Collapse
Affiliation(s)
- Michelle L. James
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | - Bin Shen
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | - Carsten H. Nielsen
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
- Cluster for Molecular Imaging and Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Deepak Behera
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | | | - Christophe Mesangeau
- Department of Medicinal Chemistry, University of Mississippi, University, Mississippi
| | - Cristina Zavaleta
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | - Pradeep K. Vuppala
- Department of Pharmaceutics, University of Mississippi, University, Mississippi
| | | | - Bonnie A. Avery
- Department of Pharmaceutics, University of Mississippi, University, Mississippi
| | - David M. Lyons
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California
| | | | - Sandip Biswal
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | - Sanjiv S. Gambhir
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
- Department of Bioengineering, Department of Materials Science and Engineering, Stanford University, Stanford, California
| | - Frederick T. Chin
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| |
Collapse
|
47
|
Jin H, Fan J, Zhang X, Li J, Flores HP, Perlmutter JS, Parsons SM, Tu Z. Radiosynthesis and in vivo evaluation of a novel σ 1 selective PET ligand. Medchemcomm 2014; 5:1669-1677. [PMID: 25584182 DOI: 10.1039/c4md00240g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The σ1 receptor is an important target for CNS disorders. We previously identified a σ1 ligand TZ3108 having highly potent (Ki-σ1 = 0.48 nM) and selective affinity for σ1 versus σ2 receptors. TZ3108 was 18F-labeled with F-18 for in vivo evaluation. Biodistribution and blocking studies of [18F]TZ3108 in male Sprague-Dawley rats demonstrated high brain uptake, which was σ1-specific with no in vivo defluorination. MicroPET studies in cynomolgus macaques showed high brain penetration of [18F]TZ3108; the regional brain distribution was consistent with that of the σ1 receptor. Pseudo-equilibrium in the brain was reached ~ 45 min post-injection. Metabolite analysis of [18F]TZ3108 in NHP blood and rodent blood and brain revealed that ~ 70% parent remained in the plasma of NHPs 60 min post-injection and the major radiometabolite did not cross the blood-brain barrier in rats. In summary, the potent, selective and metabolically stable σ1 specific radioligand [18F]TZ3108 represents a potentially useful PET radioligand for quantifying the σ1 receptor in the brain.
Collapse
Affiliation(s)
- Hongjun Jin
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jinda Fan
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Xiang Zhang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Junfeng Li
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Hubert P Flores
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA. ; Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Stanley M Parsons
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| |
Collapse
|
48
|
Holl K, Falck E, Köhler J, Schepmann D, Humpf HU, Brust P, Wünsch B. Synthesis, Characterization, and Metabolism Studies of Fluspidine Enantiomers. ChemMedChem 2013; 8:2047-56. [DOI: 10.1002/cmdc.201300322] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/03/2013] [Indexed: 11/12/2022]
|
49
|
Teodoro R, Moldovan RP, Lueg C, Günther R, Donat CK, Ludwig FA, Fischer S, Deuther-Conrad W, Wünsch B, Brust P. Radiofluorination and biological evaluation of N-aryl-oxadiazolyl-propionamides as potential radioligands for PET imaging of cannabinoid CB2 receptors. Org Med Chem Lett 2013; 3:11. [PMID: 24063584 PMCID: PMC3856494 DOI: 10.1186/2191-2858-3-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/15/2013] [Indexed: 11/10/2022] Open
Abstract
Background The level of expression of cannabinoid receptor type 2 (CB2R) in healthy and diseased brain has not been fully elucidated. Therefore, there is a growing interest to assess the regional expression of CB2R in the brain. Positron emission tomography (PET) is an imaging technique, which allows quantitative monitoring of very low amounts of radiolabelled compounds in living organisms at high temporal and spatial resolution and, thus, has been widely used as a diagnostic tool in nuclear medicine. Here, we report on the radiofluorination of N-aryl-oxadiazolyl-propionamides at two different positions in the lead structure and on the biological evaluation of the potential of the two tracers [18F]1 and [18F]2 as CB2 receptor PET imaging agents. Results High binding affinity and specificity towards CB2 receptors of the lead structure remained unaffected by the structural changes such as the insertion of the aliphatic and aromatic fluorine in the selected labelling sites of 1 and 2. Aliphatic and aromatic radiofluorinations were optimized, and [18F]1 and [18F]2 were achieved in radiochemical yields of ≥30% with radiochemical purities of ≥98% and specific activities of 250 to 450 GBq/μmol. Organ distribution studies in female CD1 mice revealed that both radiotracers cross the blood–brain barrier (BBB) but undergo strong peripheral metabolism. At 30 min after injection, unmetabolized [18F]1 and [18F]2 accounted for 60% and 2% as well as 68% and 88% of the total activity in the plasma and brain, respectively. The main radiometabolite of [18F]2 could be identified as the free acid [18F]10, which has no affinity towards the CB1 and CB2 receptors but can cross the BBB. Conclusions N-aryl-oxadiazolyl-propionamides can successfully be radiolabelled with 18F at different positions. Fluorine substitution at these positions did not affect affinity and specificity towards CB2R. Despite a promising in vitro behavior, a rather rapid peripheral metabolism of [18F]1 and [18F]2 in mice and the generation of brain permeable radiometabolites hamper the application of these radiotracers in vivo. However, it is expected that future synthetic modification aiming at a replacement of metabolically susceptible structural elements of [18F]1 and [18F]2 will help to elucidate the potential of this class of compounds for CB2R PET studies.
Collapse
Affiliation(s)
- Rodrigo Teodoro
- Department of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstraße 58-62, 48149 Münster, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Li Y, Wang X, Zhang J, Deuther-Conrad W, Xie F, Zhang X, Liu J, Qiao J, Cui M, Steinbach J, Brust P, Liu B, Jia H. Synthesis and Evaluation of Novel 18F-Labeled Spirocyclic Piperidine Derivatives as σ1 Receptor Ligands for Positron Emission Tomography Imaging. J Med Chem 2013; 56:3478-91. [DOI: 10.1021/jm301734g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yan Li
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Xia Wang
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Jinming Zhang
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Fang Xie
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Xiaojun Zhang
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Jian Liu
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Jinping Qiao
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Mengchao Cui
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Jörg Steinbach
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Peter Brust
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Boli Liu
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Hongmei Jia
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| |
Collapse
|