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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] [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.
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Peterson LM, Kurland BF, Schubert EK, Link JM, Gadi VK, Specht JM, Eary JF, Porter P, Shankar LK, Mankoff DA, Linden HM. A phase 2 study of 16α-[18F]-fluoro-17β-estradiol positron emission tomography (FES-PET) as a marker of hormone sensitivity in metastatic breast cancer (MBC). Mol Imaging Biol 2014; 16:431-40. [PMID: 24170452 PMCID: PMC4169237 DOI: 10.1007/s11307-013-0699-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/11/2013] [Accepted: 10/02/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE 16α-[(18)F]-fluoro-17β-estradiol positron emission tomography (FES-PET) quantifies estrogen receptor (ER) expression in tumors and may provide diagnostic benefit. PROCEDURES Women with newly diagnosed metastatic breast cancer (MBC) from an ER-positive primary tumor were imaged before starting endocrine therapy. FES uptake was evaluated qualitatively and quantitatively, and associated with response and with ER expression. RESULTS Nineteen patients underwent FES imaging. Fifteen had a biopsy of a metastasis and 15 were evaluable for response. Five patients had quantitatively low FES uptake, six had at least one site of qualitatively FES-negative disease. All patients with an ER-negative biopsy had both low uptake and at least one site of FES-negative disease. Of response-evaluable patients, 2/2 with low FES standard uptake value tumors had progressive disease within 6 months, as did 2/3 with qualitatively FES-negative tumors. CONCLUSIONS Low/absent FES uptake correlates with lack of ER expression. FES-positron emission tomography can help identify patients with endocrine resistant disease and safely measures ER in MBC.
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Affiliation(s)
- Lanell M Peterson
- Radiology/Nuclear Medicine, University of Washington Medical Center-Seattle Cancer Care Alliance, Seattle, WA, USA,
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Qin C, Lan X, He J, Xia X, Tian Y, Pei Z, Yuan H, Zhang Y. An in vitro and in vivo evaluation of a reporter gene/probe system hERL/(18)F-FES. PLoS One 2013; 8:e61911. [PMID: 23593502 PMCID: PMC3625158 DOI: 10.1371/journal.pone.0061911] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 03/14/2013] [Indexed: 11/18/2022] Open
Abstract
Purpose To evaluate the feasibility of a reporter gene/probe system, namely the human estrogen receptor ligand binding domain (hERL)/16α-[18F] fluoro-17β-estradiol (18F-FES), for monitoring gene and cell therapy. Methods The recombinant adenovirus vector Ad5-hERL-IRES-VEGF (Ad-EIV), carrying a reporter gene (hERL) and a therapeutic gene (vascular endothelial growth factor, VEGF165) through an internal ribosome entry site (IRES), was constructed. After transfection of Ad-EIV into bone marrow mesenchymal stem cells (Ad-EIV-MSCs), hERL and VEGF165 mRNA and protein expressions were identified using Real-Time qRT-PCR and immunofluorescence. The uptake of 18F-FES was measured in both Ad-EIV-MSCs and nontransfected MSCs after different incubation time. Micro-PET/CT images were obtained at 1 day after injection of Ad-EIV-MSCs into the left foreleg of the rat. The right foreleg was injected with nontransfected MSCs, which served as self-control. Results After transfection with Ad-EIV, the mRNA and protein expression of hERL and VEGF165 were successfully detected in MSCs, and correlated well with each other (R2 = 0.9840, P<0.05). This indicated the reporter gene could reflect the therapeutic gene indirectly. Ad-EIV-MSCs uptake of 18F-FES increased with incubation time with a peak value of 9.13%±0.33% at 150 min, which was significantly higher than that of the control group. A far higher level of radioactivity could be seen in the left foreleg on the micro-PET/CT image than in the opposite foreleg. Conclusion These preliminary in vitro and in vivo studies confirmed that hERL/18F-FES might be used as a novel reporter gene/probe system for monitoring gene and cell therapy. This imaging platform may have broad applications for basic research and clinical studies.
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Affiliation(s)
- Chunxia Qin
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoli Lan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- * E-mail:
| | - Jiang He
- Department of Radiology and Medical Imaging, University of Virginia, School of Medicine, Charlottesville, Virginia, United States of America
| | - Xiaotian Xia
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yueli Tian
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhijun Pei
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Yuan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yongxue Zhang
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Kong FL, Kim EE, Yang DJ. Targeted nuclear imaging of breast cancer: status of radiotracer development and clinical applications. Cancer Biother Radiopharm 2011; 27:105-12. [PMID: 21877909 DOI: 10.1089/cbr.2011.1025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Breast cancer is the most common cancer in women worldwide. Molecular imaging plays an important role in breast cancer diagnosis, staging, and treatment response evaluation. Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are the main clinical molecular imaging modalities that are based on the detection of radiotracers. This article discusses the typical radiotracers used for breast cancer imaging by PET and SPECT. In addition, radiotracers that are currently applied for human breast cancer imaging or under clinical trials are also reviewed in compliance with the categories of tumor-specific targets to which they are aimed at.
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Affiliation(s)
- Fan-Lin Kong
- Department of Experimental Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, 77030, USA.
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Wüst F, Müller M, Bergmann R. Synthesis of 4-([18F]fluoromethyl)-2-chlorophenylisothiocyanate: A novel bifunctional 18F-labelling agent. RADIOCHIM ACTA 2009. [DOI: 10.1524/ract.92.4.349.35590] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
The one-step radiosynthesis of 4-([18F]fluoromethyl)-2-chlorophenylisothiocyanate 18F-7 as a novel bifunctional 18F-labelling agent is described. Optimised reaction conditions in a remotely controlled synthesis module gave isothiocyanate 18F-7 in radiochemical yields of 45% (decay-corrected) within 40 min and high radiochemical purity of >95% after solid-phase-extraction. Coupling of compound 18F-7 with the primary amine benzylamine as a model reaction afforded the corresponding ((4-[18F]fluoromethyl)-2-chloro-phenyl)-benzyl thiourea 18F-8 in a high radiochemical yield of >90%. Stability studies of thiourea 18F-8 in terms of radiodefluorination showed appreciable buffer stability at pH 7.4, whereas significant radiodefluorination was observed when 18F-8 was incubated in buffers at pH 3.6 and pH 9.4. Preliminary dynamic PET studies with thiourea 18F-8 in male Wistar rats showed high bone accumulation, indicative of high in vivo radiodefluorination.
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Abstract
Estrogen receptor (ER) expression is an important determinant of breast cancer behavior and is critical for response to endocrine therapies such as tamoxifen and aromatase inhibitors. In current practice, ER expression is determined by assay of biopsy material. In more advanced disease, tissue assay may present practical difficulties and be associated with significant sampling error. This and other considerations motivated the development of ER imaging agents for positron emission tomography (PET), of which the most successful has been (18)F-16alpha-17beta-fluoroestradiol (FES). In this review, we highlight aspects of ER biology and the importance of the ER in breast cancer therapy; review the structure and synthesis of FES; describe its kinetics and safety/dosimetry data; and highlight validation studies. Also discussed are early results in patients using FES-PET to localize ER-expressing tumors and associated data pointing toward its accuracy as a predictive assay for breast cancer endocrine therapy. Finally, early data for tumors and sites other than breast cancer are mentioned. Preliminary data strongly point toward potential clinical utility for FES-PET, motivating further validation and future clinical trials with prospective endpoints tested under appropriate regulatory oversight.
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Affiliation(s)
- Lavanya Sundararajan
- Department of Medicine, University of Washington and Seattle Cancer Care Alliance, Seattle, WA, USA
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Gester S, Wuest F, Pawelke B, Bergmann R, Pietzsch J. Synthesis and biodistribution of an 18F-labelled resveratrol derivative for small animal positron emission tomography. Amino Acids 2005; 29:415-28. [PMID: 15997411 DOI: 10.1007/s00726-005-0205-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2004] [Accepted: 02/07/2005] [Indexed: 11/25/2022]
Abstract
Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a naturally occurring phytoalexin and polyphenol existing in grapes and various other plants, and one of the best known 'nutriceuticals'. It shows a multiplicity of beneficial biological effects, particularly, by attenuating atherogenic, inflammatory, and carcinogenic processes. However, despite convincing evidence from experimental and clinical studies, data concerning the role of resveratrol and other members of the large polyphenols family for human health is still a matter of debate. One reason for this is the lack of suitable sensitive and specific methods, which would allow direct assessment of biodistribution, biokinetics, and the metabolic fate of these compounds in vivo. The unique features of positron emission tomography (PET) as a non-invasive in vivo imaging methodology in combination with suitable PET radiotracers have great promise to assess quantitative information on physiological effects of polyphenols in vivo. Herein we describe the radiosynthesis of an (18)F-labelled resveratrol derivative, 3,5-dihydroxy-4'-[(18)F]fluoro-trans-stilbene ([(18)F]-1), using the Horner-Wadsworth-Emmons reaction as a novel radiolabelling technique in PET radiochemistry for subsequent functional imaging of polyphenol metabolism in vivo. In a typical "three-step/one-pot" reaction, (18)F-labelled resveratrol derivative [(18)F]-1 could be synthesized within 120-130 min including HPLC separation at a specific radioactivity of about 90 GBq/mumol. The radiochemical yield was about 9% (decay-corrected) related to [(18)F]fluoride and the radiochemical purity exceeded 97%. First radiopharmacological evaluation included measurement of biodistribution ex vivo and positron emission tomography (PET) studies in vivo after intravenous application of [(18)F]-1 in male Wistar rats using a dedicated small animal PET camera with very high spatial resolution. Concordantly with data on bioavailability and metabolism of native resveratrol from the literature, these investigations revealed an extensive uptake and metabolism in the liver and kidney, respectively, of [(18)F]-1. This study represents the first investigation of polyphenols in vivo by means of PET.
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Affiliation(s)
- S Gester
- Positron Emission Tomography Center, Institute of Bioinorganic and Radiopharmaceutical Chemistry, Research Center Rossendorf, Dresden, Germany
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Brust P, Rodig H, Römer J, Kasch H, Bergmann R, Füchtner F, Zips D, Baumann M, Steinbach J, Johannsen B. Distribution of 16alpha-[18F]fluoro-estradiol-3,17beta-disulfamate in rats, tumour-bearing mice and piglets. Appl Radiat Isot 2002; 57:687-95. [PMID: 12433043 DOI: 10.1016/s0969-8043(02)00184-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Based on a high affinity to the enzyme estrone sulfatase (ES), 16alpha-[18F]fluoroestradiol-3,17beta-disulfamate ([18F]FESDS) has been suggested as a potential PET radiotracer for imaging steroid-dependent breast tumours. The distribution of [18F]FESDS was studied in rats, tumour-bearing nude mice and piglets. In all species evidence for binding to a second target, the enzyme carbonic anhydrase (CA), was obtained. ES and CA inhibitors significantly reduced the radiotracer uptake in various organs but not in tumours. It is concluded that [18F]FESDS binds to ES and CA in vivo but this binding is not strong enough to allow tumour imaging with positron emission tomography (PET).
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Affiliation(s)
- P Brust
- Forschungszentrum Rossendorf, Dresden, Germany.
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Rodig H, Brust P, Römer J, Kasch H, Bergmann R, Füchtner F, Steinbach J, Johannsen B. Distribution of estrone sulfatase in rat brain determined by in vitro autoradiography with 16alpha-[18F]fluoroestradiol-3,17beta-disulfamate. Appl Radiat Isot 2002; 56:773-80. [PMID: 12102332 DOI: 10.1016/s0969-8043(02)00060-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
16Alpha-fluoroestradiol-3,17beta-disulfamate (FESDS) strongly inhibits estrone sulfatase (ES), an enzyme which is also present in the brain. The enzyme is probably involved in important regulatory functions of neurosteroids which may be disturbed in certain brain diseases. In the present study, [18F]FESDS was used to measure the amount of ES in various rat brain regions using quantitative in vitro autoradiography. The obtained values vary between 0.29 pmol (mg protein)(-1) (pons) and 11.5 pmol (mg protein)(-1) (striatum). They are positively correlated with the enzyme activity measured in homogenates of the corresponding regions. Because this radiotracer binds also to carbonic anhydrase in the brain it is only of limited use for in vivo imaging studies.
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Affiliation(s)
- H Rodig
- Forschungszentrum Rossendorf, Dresden, Germany
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