1
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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] [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.
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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
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2
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Lüken J, Goerges G, Ritter N, Disse P, Schreiber JA, Schmidt J, Frehland B, Schepmann D, Seebohm G, Wünsch B. Indazole as a Phenol Bioisostere: Structure-Affinity Relationships of GluN2B-Selective NMDA Receptor Antagonists. J Med Chem 2023; 66:11573-11588. [PMID: 37580890 DOI: 10.1021/acs.jmedchem.3c01161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
Negative allosteric modulation of GluN2B subunit-containing NMDA receptors prevents overstimulation, resulting in neuroprotective effects. Since the phenol of prominent negative allosteric modulators is prone to rapid glucuronidation, its bioisosteric replacement by an indazole was envisaged. The key step in the synthesis was a Sonogashira reaction of non-protected iodoindazoles with propargylpiperidine derivatives. Modification of the alkynyl moiety allowed the introduction of several functional groups. The synthesized indazoles showed very high GluN2B affinity but limited selectivity over σ receptors. Molecular dynamics simulations revealed the same molecular interactions with the ifenprodil binding site as the analogous phenols. In two-electrode voltage-clamp experiments, enantiomeric 3-(4-benzylpiperidin-1-yl)-1-(1H-indazol-5-yl)propan-1-ols (S)-10a and (R)-10a displayed higher inhibitory activity than ifenprodil. In contrast to phenolic GluN2B antagonists, the indazoles were not conjugated with glucuronic acid. It can be concluded that the phenol of potent GluN2B antagonists can be replaced bioisosterically by an indazole, retaining the high GluN2B affinity and activity but inhibiting glucuronidation.
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Affiliation(s)
- Judith Lüken
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Gunnar Goerges
- Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
| | - Nadine Ritter
- Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
- GRK 2515, Chemical Biology of Ion Channels (Chembion), Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Paul Disse
- Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
- GRK 2515, Chemical Biology of Ion Channels (Chembion), Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Julian A Schreiber
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
- Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
| | - Judith Schmidt
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Bastian Frehland
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Dirk Schepmann
- Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Guiscard Seebohm
- Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Robert-Koch-Str. 45, D-48149 Münster, Germany
- GRK 2515, Chemical Biology of Ion Channels (Chembion), Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - 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
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3
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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] [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.
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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
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Bechthold E, Schreiber JA, Ritter N, Grey L, Schepmann D, Daniliuc C, González-Cano R, Nieto FR, Seebohm G, Wünsch B. Synthesis of tropane-based σ1 receptor antagonists with antiallodynic activity. Eur J Med Chem 2022; 230:114113. [DOI: 10.1016/j.ejmech.2022.114113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/08/2022] [Accepted: 01/08/2022] [Indexed: 11/03/2022]
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Torres-Gómez H, Daniliuc C, Schepmann D, Laurini E, Pricl S, Wünsch B. Propellanes as Rigid Scaffolds for the Stereodefined Attachment of σ-Pharmacophoric Structural Elements to Achieve σ Affinity. Int J Mol Sci 2021; 22:ijms22115685. [PMID: 34073622 PMCID: PMC8199339 DOI: 10.3390/ijms22115685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/20/2021] [Accepted: 05/22/2021] [Indexed: 01/07/2023] Open
Abstract
Following the concept of conformationally restriction of ligands to achieve high receptor affinity, we exploited the propellane system as rigid scaffold allowing the stereodefined attachment of various substituents. Three types of ligands were designed, synthesized and pharmacologically evaluated as σ1 receptor ligands. Propellanes with (1) a 2-methoxy-5-methylphenylcarbamate group at the "left" five-membered ring and various amino groups on the "right" side; (2) benzylamino or analogous amino moieties on the "right" side and various substituents at the left five-membered ring and (3) various urea derivatives at one five-membered ring were investigated. The benzylamino substituted carbamate syn,syn-4a showed the highest σ1 affinity within the group of four stereoisomers emphasizing the importance of the stereochemistry. The cyclohexylmethylamine 18 without further substituents at the propellane scaffold revealed unexpectedly high σ1 affinity (Ki = 34 nM) confirming the relevance of the bioisosteric replacement of the benzylamino moiety by the cyclohexylmethylamino moiety. Reduction of the distance between the basic amino moiety and the "left" hydrophobic region by incorporation of the amino moiety into the propellane scaffold resulted in azapropellanes with particular high σ1 affinity. As shown for the propellanamine 18, removal of the carbamate moiety increased the σ1 affinity of 9a (Ki = 17 nM) considerably. Replacement of the basic amino moiety by H-bond forming urea did not lead to potent σ ligands. According to molecular dynamics simulations, both azapropellanes anti-5 and 9a as well as propellane 18 adopt binding poses at the σ1 receptor, which result in energetic values correlating well with their different σ1 affinities. The affinity of the ligands is enthalpy driven. The additional interactions of the carbamate moiety of anti-5 with the σ1 receptor protein cannot compensate the suboptimal orientations of the rigid propellane and its N-benzyl moiety within the σ1 receptor-binding pocket, which explains the higher σ1 affinity of the unsubstituted azapropellane 9a.
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Affiliation(s)
- Héctor Torres-Gómez
- Department of Chemistry and Pharamcy, Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany; (H.T.-G.); (D.S.)
| | - Constantin Daniliuc
- Department of Chemistry and Pharamcy, Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, D-48149 Münster, Germany;
| | - Dirk Schepmann
- Department of Chemistry and Pharamcy, Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany; (H.T.-G.); (D.S.)
| | - Erik Laurini
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTS), Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy; (S.P.); (E.L.)
| | - Sabrina Pricl
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTS), Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy; (S.P.); (E.L.)
- Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland
| | - Bernhard Wünsch
- Department of Chemistry and Pharamcy, Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany; (H.T.-G.); (D.S.)
- GRK 2515, Chemical Biology of Ion Channels (Chembion), Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
- Correspondence: ; Tel.: +49-251-833-3311; Fax: +49-251-833-2144
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6
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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] [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.
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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
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7
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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] [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.
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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
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8
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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] [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).
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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.
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9
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Voltammetric and electrogeneration approaches for the assessment of the oxidative drug metabolism. Anal Bioanal Chem 2018; 410:2229-2239. [DOI: 10.1007/s00216-018-0897-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/12/2018] [Accepted: 01/16/2018] [Indexed: 12/26/2022]
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Ortmeyer CP, Haufe G, Schwegmann K, Hermann S, Schäfers M, Börgel F, Wünsch B, Wagner S, Hugenberg V. Synthesis and evaluation of a [ 18F]BODIPY-labeled caspase-inhibitor. Bioorg Med Chem 2017; 25:2167-2176. [PMID: 28284866 DOI: 10.1016/j.bmc.2017.02.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/11/2017] [Accepted: 02/14/2017] [Indexed: 12/31/2022]
Abstract
BODIPYs (boron dipyrromethenes) are fluorescent dyes which show high stability and quantum yields. They feature the possibility of selective 18F-fluorination at the boron-core. Attached to a bioactive molecule and labeled with [18F]fluorine, the resulting compounds are promising tracers for multimodal imaging in vivo and can be used for PET and fluorescence imaging. A BODIPY containing a phenyl and a hydroxy substituent on boron was synthesized and characterized. Fluorinated and hydroxy substituted dyes were coupled to an isatin-based caspase inhibitor via cycloaddition and the resulting compounds were evaluated in vitro in caspase inhibition assays. The metabolic stability and the formed metabolites were investigated by incubation with mouse liver microsomes and LC-MS analysis. Subsequently the fluorophores were labeled with [18F]fluorine and an in vivo biodistribution study using dynamic PET was performed.
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Affiliation(s)
- Christian Paul Ortmeyer
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, D-48149 Münster, Germany; Organic Chemistry Institute, University of Münster, Corrensstr. 40, D-48149 Münster, Germany
| | - Günter Haufe
- Organic Chemistry Institute, University of Münster, Corrensstr. 40, D-48149 Münster, Germany; Cells-in-Motion Cluster of Excellence, University of Münster, Waldeyerstr. 15, D-48149 Münster, Germany.
| | - Katrin Schwegmann
- European Institute for Molecular Imaging, University of Münster, Waldeyerstr. 15, D-48149 Münster, Germany
| | - Sven Hermann
- European Institute for Molecular Imaging, University of Münster, Waldeyerstr. 15, D-48149 Münster, Germany
| | - Michael Schäfers
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, D-48149 Münster, Germany; Cells-in-Motion Cluster of Excellence, University of Münster, Waldeyerstr. 15, D-48149 Münster, Germany; European Institute for Molecular Imaging, University of Münster, Waldeyerstr. 15, D-48149 Münster, Germany
| | - Frederik Börgel
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstr. 48, D-48149 Münster, Germany
| | - Bernhard Wünsch
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstr. 48, D-48149 Münster, Germany
| | - Stefan Wagner
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, D-48149 Münster, Germany
| | - Verena Hugenberg
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, HDZ NRW, Georgstr. 11, D-32545 Bad Oeynhausen, Germany
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