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Gröner B, Hoffmann C, Endepols H, Urusova EA, Brugger M, Neumaier F, Timmer M, Neumaier B, Zlatopolskiy BD. Radiosynthesis and Preclinical Evaluation of m-[ 18F]FET and [ 18F]FET-OMe as Novel [ 18F]FET Analogs for Brain Tumor Imaging. Mol Pharm 2024; 21:2795-2812. [PMID: 38747353 DOI: 10.1021/acs.molpharmaceut.3c01215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
O-([18F]Fluoroethyl)-l-tyrosine ([18F]FET) is actively transported into the brain and cancer cells by LAT1 and possibly other amino acid transporters, which enables brain tumor imaging by positron emission tomography (PET). However, tumor delivery of this probe in the presence of competing amino acids may be limited by a relatively low affinity for LAT1. The aim of the present work was to evaluate the meta-substituted [18F]FET analog m-[18F]FET and the methyl ester [18F]FET-OMe, which were designed to improve tumor delivery by altering the physicochemical, pharmacokinetic, and/or transport properties. Both tracers could be prepared with good radiochemical yields of 41-56% within 66-90 min. Preclinical evaluation with [18F]FET as a reference tracer demonstrated reduced in vitro uptake of [18F]FET-OMe by U87 glioblastoma cells and no advantage for in vivo tumor imaging. In contrast, m-[18F]FET showed significantly improved in vitro uptake and accelerated in vivo tumor accumulation in an orthotopic glioblastoma model. As such, our work identifies m-[18F]FET as a promising alternative to [18F]FET for brain tumor imaging that deserves further evaluation with regard to its transport properties and in vivo biodistribution.
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Affiliation(s)
- Benedikt Gröner
- Forschungszentrum Jülich GmbH, Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Wilhelm-Johnen-Straße, Jülich 52428, Germany
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
| | - Chris Hoffmann
- Forschungszentrum Jülich GmbH, Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Wilhelm-Johnen-Straße, Jülich 52428, Germany
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
| | - Heike Endepols
- Forschungszentrum Jülich GmbH, Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Wilhelm-Johnen-Straße, Jülich 52428, Germany
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
- Faculty of Medicine and University Hospital Cologne, Department of Nuclear Medicine, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
| | - Elizaveta A Urusova
- Forschungszentrum Jülich GmbH, Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Wilhelm-Johnen-Straße, Jülich 52428, Germany
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
| | - Melanie Brugger
- Forschungszentrum Jülich GmbH, Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Wilhelm-Johnen-Straße, Jülich 52428, Germany
| | - Felix Neumaier
- Forschungszentrum Jülich GmbH, Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Wilhelm-Johnen-Straße, Jülich 52428, Germany
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
| | - Marco Timmer
- Faculty of Medicine and University Hospital Cologne, Center for Neurosurgery, Department of General Neurosurgery, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
| | - Bernd Neumaier
- Forschungszentrum Jülich GmbH, Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Wilhelm-Johnen-Straße, Jülich 52428, Germany
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
| | - Boris D Zlatopolskiy
- Forschungszentrum Jülich GmbH, Nuclear Chemistry (INM-5), Institute of Neuroscience and Medicine, Wilhelm-Johnen-Straße, Jülich 52428, Germany
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, Cologne 50937, Germany
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Yang SK, Chen SJ, Huang JD. Enantioselectivity suggests a cytosolic origin for a commercial pig liver esterase preparation. Chirality 1995; 7:40-3. [PMID: 7702997 DOI: 10.1002/chir.530070108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A widely utilized pig liver esterase preparation has been found to be derived essentially exclusively from the cytosolic fraction of pig livers. Esterases in cytosol and microsomes prepared from a fresh pig liver hydrolyzed the S- and R-enantiomers of racemic oxazepam 3-acetate (rac-OXA) with specific activity ratios of approximately 2.3:1 and 1:62, respectively. Product formations were analyzed by chiral stationary phase high-performance liquid chromatography. The commercial pig liver esterase preparation showed greater activity toward S-OXA than did the esterases in the cytosolic fraction prepared from fresh pig liver. The results established that (i) esterases contained in microsomes and cytosol of pig liver have opposite enantioselectivity in the hydrolysis of rac-OXA and (ii) the commercial pig liver esterase preparation has a cytosolic origin.
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Affiliation(s)
- S K Yang
- Department of Pharmacology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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