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McHugh CI, Lawhorn-Crews JM, Modi D, Douglas KA, Jones SK, Mangner TJ, Collins JM, Shields AF. Effects of capecitabine treatment on the uptake of thymidine analogs using exploratory PET imaging agents: 18F-FAU, 18F-FMAU, and 18F-FLT. Cancer Imaging 2016; 16:34. [PMID: 27751167 PMCID: PMC5067904 DOI: 10.1186/s40644-016-0092-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 10/03/2016] [Indexed: 12/02/2022] Open
Abstract
Background A principal goal for the use of positron emission tomography (PET) in oncology is for real-time evaluation of tumor response to chemotherapy. Given that many contemporary anti-neoplastic agents function by impairing cellular proliferation, it is of interest to develop imaging modalities to monitor these pathways. Here we examined the effect of capecitabine on the uptake of thymidine analogs used with PET: 3’-deoxy-3’-[18F]fluorothymidine (18F-FLT), 1-(2’-deoxy-2’-[18F]fluoro-β-D-arabinofuranosyl) thymidine (18F-FMAU), and 1-(2’-deoxy-2’-[18F]fluoro-β-D-arabinofuranosyl) uracil (18F-FAU) in patients with advanced cancer. Methods Fifteen patients were imaged, five with each imaging agent. Patients had been previously diagnosed with breast, colorectal, gastric, and esophageal cancers and had not received therapy for at least 4 weeks prior to the first scan, and had not been treated with any prior fluoropyrimidines. Subjects were imaged within a week before the start of capecitabine and on the second day of treatment, after the third dose of capecitabine. Tracer uptake was quantified by mean standard uptake value (SUVmean) and using kinetic analysis. Results Patients imaged with 18F-FLT showed variable changes in retention and two patients exhibited an increase in SUVmean of 172.3 and 89.9 %, while the other patients had changes ranging from +19.4 to -25.4 %. The average change in 18F-FMAU retention was 0.2 % (range -24.4 to 23.1) and 18F-FAU was -10.2 % (range -40.3 to 19.2). Observed changes correlated strongly with SUVmax but not kinetic measurements. Conclusions This pilot study demonstrates that patients treated with capecitabine can produce a marked increase in 18F-FLT retention in some patients, which will require further study to determine if this flare is predictive of therapeutic response. 18F-FAU and 18F-FMAU showed little change, on average, after treatment. Electronic supplementary material The online version of this article (doi:10.1186/s40644-016-0092-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christopher I McHugh
- Cancer Biology Graduate Program, Wayne State University, Detroit, MI, 48201, USA
| | - Jawana M Lawhorn-Crews
- Karmanos Cancer Institute and Oncology, Wayne State University, 4100 John R., HW04HO, Detroit, MI, 48201, USA
| | - Dipenkumar Modi
- Karmanos Cancer Institute and Oncology, Wayne State University, 4100 John R., HW04HO, Detroit, MI, 48201, USA
| | - Kirk A Douglas
- Karmanos Cancer Institute and Oncology, Wayne State University, 4100 John R., HW04HO, Detroit, MI, 48201, USA
| | - Steven K Jones
- Cancer Biology Graduate Program, Wayne State University, Detroit, MI, 48201, USA
| | | | | | - Anthony F Shields
- Karmanos Cancer Institute and Oncology, Wayne State University, 4100 John R., HW04HO, Detroit, MI, 48201, USA.
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Alauddin MM. Nucleoside-based probes for imaging tumor proliferation using positron emission tomography. J Labelled Comp Radiopharm 2013; 56:237-43. [PMID: 24285330 DOI: 10.1002/jlcr.3003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 07/03/2012] [Accepted: 11/06/2012] [Indexed: 02/03/2023]
Abstract
Cancer is one of the leading causes of human death, and early detection can be beneficial for its timely therapy and management. For the early detection of cancer, positron emission tomography (PET) is more accurate and sensitive than other imaging modalities, such as computed tomography and magnetic resonance imaging. [(18) F]-Labeled fluorodeoxyglucose is the most useful PET probe in early detection of cancer; however, its nonspecific accumulation and consequent false-positive findings warrant the identification of other PET probes. Thymidine (TdR) and its analogs have been radiolabeled for PET imaging of cellular proliferation and DNA synthesis. Because of its in vivo instability, radiolabeled TdR has not been successful in PET imaging. However, some of its radiolabeled analogs have been developed for PET imaging of cellular proliferation and DNA synthesis. In this review, the radiochemistry and production of (11) C-TdR and (11) C/(18) F-labeled TdR analogs published to date are presented.
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Affiliation(s)
- Mian M Alauddin
- Department of Experimental Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Abstract
OBJECTIVE Recent advances in the fundamental understanding of the complex biology of prostate cancer have provided an increasing number of potential targets for imaging and treatment. The imaging evaluation of prostate cancer needs to be tailored to the various phases of this remarkably heterogeneous disease. CONCLUSION In this article, I review the current state of affairs on a range of PET radiotracers for potential use in the imaging evaluation of men with prostate cancer.
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Chen K, Li Z, Conti PS. Microwave-assisted one-pot radiosynthesis of 2′-deoxy-2′-[18F]fluoro-5-methyl-1-β-d-arabinofuranosyluracil ([18F]-FMAU). Nucl Med Biol 2012; 39:1019-25. [DOI: 10.1016/j.nucmedbio.2012.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Revised: 03/09/2012] [Accepted: 03/09/2012] [Indexed: 01/05/2023]
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Ding C, Ge Q, Wang Y, Zhou Z, Zhi X, Liu X, Li Z. Normal-phase liquid chromatography coupled with electrospray ionization mass spectrometry for chiral separation and quantification of clevudine and its enantiomer in human plasma. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 885-886:97-102. [DOI: 10.1016/j.jchromb.2011.12.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 12/05/2011] [Accepted: 12/20/2011] [Indexed: 10/14/2022]
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Abstract
Positron emission tomography (PET) is one of the most rapidly growing areas of medical imaging, with many applications in the clinical management of patients with cancer. The principal goal of PET imaging is to visualize, characterize, and measure biological processes at the cellular, subcellular, and molecular levels in living subjects using noninvasive procedures. PET imaging takes advantage of the traditional diagnostic imaging techniques and introduces positron-emitting probes to determine the expression of indicative molecular targets at different stages of cancer progression. Although [(18)F]fluorodeoxyglucose ([(18)F]FDG)-PET has been widely utilized for staging and restaging of cancer, evaluation of response to treatment, differentiation of post-therapy alterations from residual or recurrent tumor, and assessment of prognosis, [(18)F]FDG is not a target-specific PET tracer. Over the last decade, numerous target-specific PET tracers have been developed and evaluated in preclinical and clinical studies. This review provides an overview of the current status and trends in the development of non-[(18)F]FDG PET probes in oncology and their application in the investigation of cancer biology.
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Affiliation(s)
- Kai Chen
- Molecular Imaging Center, Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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Cai H, Li Z, Conti PS. The improved syntheses of 5-substituted 2'-[18F]fluoro-2'-deoxy-arabinofuranosyluracil derivatives ([18F]FAU, [18F]FEAU, [18F]FFAU, [18F]FCAU, [18F]FBAU and [18F]FIAU) using a multistep one-pot strategy. Nucl Med Biol 2011; 38:659-66. [PMID: 21718941 DOI: 10.1016/j.nucmedbio.2011.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 12/28/2010] [Accepted: 01/01/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION We and others have previously reported a four-step radiosynthesis of a series of 2'-deoxy-2'-[(18)F]fluoro-5-substituted-1-β-D-arabinofuranosyluracil derivatives including [(18)F]FAU, [(18)F]FEAU, [(18)F]FFAU, [(18)F]FCAU, [(18)F]FBAU and [(18)F]FIAU as thymidine derivatives for tumor proliferation and/or reporter gene expression imaging with positron emission tomography (PET). Although the radiosynthesis has been proven to be reproducible and efficient, this complicated multistep reaction is difficult to incorporate into an automated cGMP-compliant radiosynthesis module for routine production. Recently, we have developed a simple and efficient one-pot method for routine production of [(18)F]FMAU. In this study, we studied the feasibility of radiosynthesizing [(18)F]FAU, [(18)F]FEAU, [(18)F]FFAU, [(18)F]FCAU, [(18)F]FBAU and [(18)F]FIAU using this newly developed method. METHODS Similar to the radiosynthesis of [(18)F]FMAU, 5-substituted 2'-[(18)F]fluoro-2'-deoxy-arabinofuranosyluracil derivatives ([(18)F]FAU, [(18)F]FEAU, [(18)F]FFAU, [(18)F]FCAU, [(18)F]FBAU and [(18)F]FIAU) were synthesized in one-pot radiosynthesis module in the presence of Friedel-Crafts catalyst TMSOTf and HMDS. RESULTS This one-pot radiosynthesis method could be used to produce [(18)F]FAU, [(18)F]FEAU, [(18)F]FFAU, [(18)F]FCAU, [(18)F]FBAU and [(18)F]FIAU. The overall radiochemical yields of these tracers varied from 4.1%±0.8% to 10.1%±1.9% (decay-corrected, n=4). The overall reaction time was reduced from 210 min to 150 min from the end of bombardment, and the radiochemical purity was >99%. CONCLUSIONS The improved radiosyntheses of [(18)F]FAU, [(18)F]FEAU, [(18)F]FFAU, [(18)F]FCAU, [(18)F]FBAU and [(18)F]FIAU have been achieved with reasonable yields and high purity using a multistep one-pot method. The synthetic time has been reduced, and the reaction procedures have been significantly simplified. The success of this approach may make PET tracers [(18)F]FAU, [(18)F]FEAU, [(18)F]FFAU, [(18)F]FCAU, [(18)F]FBAU and [(18)F]FIAU more accessible for preclinical and clinical research.
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Affiliation(s)
- Hancheng Cai
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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Abstract
Prostate cancer is biologically and clinically a heterogeneous disease and its imaging evaluation will need to be tailored to the specific phases of the disease in a patient-specific, risk-adapted manner. We first present a brief overview of the natural history of prostate cancer before discussing the role of various imaging tools, including opportunities and challenges, for different clinical phases of this common disease in men. We then review the preclinical and clinical evidence on the potential and emerging role of positron emission tomography with various radiotracers in the imaging evaluation of men with prostate cancer.
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Affiliation(s)
- Hossein Jadvar
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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Li Z, Cai H, Conti PS. Automated synthesis of 2'-deoxy-2'-[18F]fluoro-5-methyl-1-β-D-arabinofuranosyluracil ([18F]-FMAU) using a one reactor radiosynthesis module. Nucl Med Biol 2010; 38:201-6. [PMID: 21315275 DOI: 10.1016/j.nucmedbio.2010.08.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 08/15/2010] [Accepted: 08/25/2010] [Indexed: 10/18/2022]
Abstract
2'-Deoxy-2'-[(18)F]fluoro-5-methyl-1-β-D-arabinofuranosyluracil ([(18)F]-FMAU) is an established PET probe used to monitor cellular proliferation. For clinical applications, a fully automated cGMP-compliant radiosynthesis would be preferred. However, the current synthesis of [(18)F]-FMAU requires a multistep procedure, making the development of an automated protocol difficult and complicated. Recently, we have developed a significantly simplified one-pot reaction condition for the synthesis of [(18)F]-FMAU in the presence of Friedel-Crafts catalysts. Here, we report a fully automated synthesis of [(18)F]-FMAU based on a one reactor radiosynthesis module using our newly developed synthetic method. The product was purified on a semi-preparative high-performance liquid chromatography integrated with the synthesis module using 6% EtOH in 10 mM phosphate buffer or 8% MeCN/water. [(18)F]-FMAU was obtained in 12±3% radiochemical yield (decay corrected overall yield based on [(18)F]-F(-), n=4) with 383±33 mCi/μmol specific activity at the time of injection. The α/β anomer ratio was 4:6. The overall reaction time was about 150 min from the end of bombardment and the radiochemical purity was >99%. This automated synthesis should also be suitable for the production of other 5-substituted thymidine analogues.
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Affiliation(s)
- Zibo Li
- Department of Radiology, Keck School of Medicine, Molecular Imaging Center, University of Southern California, Los Angeles, CA 90033, USA
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Small animal tumour imaging with MRI and the ECAT EXACT scanner: application of partial volume correction and comparison with microPET data. Nucl Med Commun 2010; 31:294-300. [PMID: 20023592 DOI: 10.1097/mnm.0b013e328334fc2a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Partial volume effects caused by limited spatial resolution of conventional positron emission tomography (PET) scanners result in an underestimation of the activity concentration in small tumours. The aim of the study was to evaluate the feasibility of small animal tumour imaging with the clinical PET scanner ECAT EXACT after partial volume correction based on MRI calculations. The same tumour model was examined additionally with the small animal PET system, microPET focus 120. METHODS Before the ECAT EXACT studies recovery coefficients for different sphere volumes were generated with phantom experiments. For the following in-vivo study DS-sarcoma cells were implanted on both hind foot dorsum of male Sprague-Dawley rats. In-vivo tumour volume calculations were done with the high-resolution MRI system, Magnetom Vision Experimental. Dynamic F-fluorodeoxyglucose (FDG) PET was performed with the scanner ECAT EXACT (5 MBq intravenous, two-dimensional mode, n = 16 tumours) or with the microPET focus 120 (20 MBq intravenous, two-dimensional mode, n = 10 tumours). The animals were then killed, the tumours rapidly explanted, weighed and homogenized. The concentration of F-FDG was measured with a gamma counter and decay corrected; the ex-vivo F-FDG concentration was compared with the mean tumour activity concentration of the PET data. RESULTS Using the ECAT EXACT mean underestimation of actual tumour F-FDG concentration was 35.4%, for partial volume-corrected data this error decreased to 1.7%. In addition, after partial volume correction congruence and linear correlation between the regions of interest-based activity concentration and ex-vivo measurements were excellent (r = 0.98). These results were quite similar to the microPET experiments without partial volume correction: r = 0.99. CONCLUSION These data indicate that partial volume correction might allow use of the clinical PET system, ECAT EXACT, for the metabolic assessment of small animal tumours >/=10 mm with sufficient accuracy if no dedicated animal PET is available.
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11
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Paolillo V, Riese S, Gelovani JG, Alauddin MM. A fully automated synthesis of [18F]-FEAU and [18F]-FMAU using a novel dual reactor radiosynthesis module. J Labelled Comp Radiopharm 2009. [DOI: 10.1002/jlcr.1674] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Dunphy MPS, Lewis JS. Radiopharmaceuticals in preclinical and clinical development for monitoring of therapy with PET. J Nucl Med 2009; 50 Suppl 1:106S-21S. [PMID: 19380404 DOI: 10.2967/jnumed.108.057281] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This review article discusses PET agents, other than (18)F-FDG, with the potential to monitor the response to therapy before, during, or after therapeutic intervention. This review deals primarily with non-(18)F-FDG PET tracers that are in the final stages of preclinical development or in the early stages of clinical application for monitoring the therapeutic response. Four sections related to the nature of the tracers are included: radiotracers of DNA synthesis, such as the 2 most promising agents, the thymidine analogs 3'-(18)F-fluoro-3'-deoxythymidine and (18)F-1-(2'-deoxy-2'-fluoro-beta-d-arabinofuranosyl)thymine; agents for PET imaging of hypoxia within tumors, such as (60/62/64)Cu-labeled diacetyl-bis(N(4)-methylthiosemicarbazone) and (18)F-fluoromisonidazole; amino acids for PET imaging, including the most popular such agent, l-[methyl-(11)C]methionine; and agents for the imaging of tumor expression of androgen and estrogen receptors, such as 16beta-(18)F-fluoro-5alpha-dihydrotestosterone and 16alpha-(18)F-fluoro-17beta-estradiol, respectively.
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Affiliation(s)
- Mark P S Dunphy
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA
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Ambrosini V, Quarta C, Nanni C, Pettinato C, Franchi R, Grassetto G, Al-Nahhas A, Fanti S, Rubello D. Small Animal PET in Oncology: The Road from Bench to Bedside. Cancer Biother Radiopharm 2009; 24:277-85. [DOI: 10.1089/cbr.2008.0554] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Valentina Ambrosini
- Department of Nuclear Medicine, Policlinico “S. Orsola-Malpighi,” Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Carmelo Quarta
- Department of Nuclear Medicine, Policlinico “S. Orsola-Malpighi,” Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Cristina Nanni
- Department of Nuclear Medicine, Policlinico “S. Orsola-Malpighi,” Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Cinzia Pettinato
- Medical Physics Unit, Policlinico “S. Orsola-Malpighi,” Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Roberto Franchi
- Department of Nuclear Medicine, Policlinico “S. Orsola-Malpighi,” Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Gaia Grassetto
- Department of Nuclear Medicine, “S. Maria della Misericordia” Hospital, Rovigo, Italy
| | - Adil Al-Nahhas
- Department of Nuclear Medicine, Hammersmith Hospital, London, United Kingdom
| | - Stefano Fanti
- Department of Nuclear Medicine, Policlinico “S. Orsola-Malpighi,” Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Domenico Rubello
- Department of Nuclear Medicine, “S. Maria della Misericordia” Hospital, Rovigo, Italy
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Nimmagadda S, Shields AF. The role of DNA synthesis imaging in cancer in the era of targeted therapeutics. Cancer Metastasis Rev 2008; 27:575-87. [PMID: 18512023 DOI: 10.1007/s10555-008-9148-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Non-specific targets such as DNA and microtubules have been the mainstay of cancer therapeutics and the most effective clinical agents until a decade ago. Advances in genetics, molecular and cellular biology over the past decade led to the development of a new generation of agents that are far more specific and effective. In contrast to progress seen with therapeutic agents, general monitoring targets such as proliferation imaging are just gaining momentum and targeted imaging is still in its infancy. In these paradoxical times, this review assesses the role of proliferation imaging in monitoring the efficacy of targeted therapeutics.
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Affiliation(s)
- Sridhar Nimmagadda
- Russel H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
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Abstract
Increased cellular proliferation is an integral part of the cancer phenotype. Several in vitro assays have been developed to measure the rate of tumor growth, but these require biopsies, which are particularly difficult to obtain over time and in different areas of the body in patients with multiple metastatic lesions. Most of the effort to develop imaging methods to noninvasively measure the rate of tumor cell proliferation has focused on the use of PET in conjunction with tracers for the thymidine salvage pathway of DNA synthesis, because thymidine contains the only pyrimidine or purine base that is unique to DNA. Imaging with 11C-thymidine has been tested for detecting tumors and tracking their response to therapy in animals and patients. Its major limitations are the short half-life of 11C and the rapid catabolism of thymidine after injection. These limitations led to the development of analogs that are resistant to degradation and can be labeled with radionuclides more conducive to routine clinical use, such as 18F. At this point, the thymidine analogs that have been studied the most are 3'-deoxy-3'-fluorothymidine (FLT) and 1-(2'-deoxy-2'-fluoro-1-beta-d-arabinofuranosyl)-thymine (FMAU). Both are resistant to degradation and track the DNA synthesis pathway. FLT is phosphorylated by thymidine kinase 1, thus being retained in proliferating cells. It is incorporated by the normal proliferating marrow and is glucuronidated in the liver. FMAU can be incorporated into DNA after phosphorylation but shows less marrow uptake. It shows high uptake in the normal heart, kidneys, and liver, in part because of the role of mitochondrial thymidine kinase 2. Early clinical data for 18F-FLT demonstrated that its uptake correlates well with in vitro measures of proliferation. Although 18F-FLT can be used to detect tumors, its tumor-to-normal tissue contrast is generally lower than that of 18F-FDG in most cancers outside the brain. The most promising use for thymidine and its analogs is in monitoring tumor treatment response, as demonstrated in animal studies and pilot human trials. Further work is needed to determine the optimal tracer(s) and timing of imaging after treatment.
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Affiliation(s)
- James R Bading
- Department of Radioimmunotherapy, City of Hope, Duarte, California, USA
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Kao CHK, Xie HL, Liao CH, Chen WM, Kao PF. [18F]FBAU 3′,5′-dibenzoate, a lipophilic prodrug, enhances brain uptake of the cell proliferation tracer [18F]FBAU. Nucl Med Biol 2008; 35:635-43. [DOI: 10.1016/j.nucmedbio.2008.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Revised: 04/02/2008] [Accepted: 04/05/2008] [Indexed: 12/17/2022]
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Nishii R, Volgin AY, Mawlawi O, Mukhopadhyay U, Pal A, Bornmann W, Gelovani JG, Alauddin MM. Evaluation of 2'-deoxy-2'-[18F]fluoro-5-methyl-1-beta-L: -arabinofuranosyluracil ([18F]-L: -FMAU) as a PET imaging agent for cellular proliferation: comparison with [18F]-D: -FMAU and [18F]FLT. Eur J Nucl Med Mol Imaging 2008; 35:990-8. [PMID: 18057932 DOI: 10.1007/s00259-007-0649-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 10/23/2007] [Indexed: 02/03/2023]
Abstract
PURPOSE Clevudine (L: -FMAU) an un-natural analogue of thymidine, is in clinical trials for the treatment of hepatitis B virus (HBV). L: -FMAU is phosphorylated by cellular kinases such as thymidine kinase 1 and deoxycytidine kinase, and its triphosphate form inhibits HBV deoxyribonucleic acid synthesis. Thus, L: -FMAU, radiolabeled with an appropriate isotope, may be useful for positron emission tomography (PET) imaging of tumor proliferation. We evaluated [18F]-L-FMAU as a PET imaging agent in tumor-bearing mice and compared the results with those of two other radiotracers, [18F]-d-FMAU and [18F]-FLT. METHODS Subcutaneous xenografts of the human lung cancer cell lines H441 and H3255 were established in mice. A micro-PET scanner was used to obtain images of the tumor-bearing animals with [18F]-L-FMAU, [18F]-D-FMAU, and [18F]-FLT. RESULTS At 2 h postinjection, the tumor uptake (% ID/g) of 18F]-L: -FMAU, 18F]-D: -FMAU, and [18F]-FLT in the faster-growing H441 cells was 3.13 +/- 1.11, 7.74 +/- 1.39, and 5.10 +/- 1.45, respectively. The corresponding values for the slower-growing H3255 cells were 1.38 +/- 0.81, 4.49 +/- 1.08, and 0.57 +/- 0.33. Tumor/muscle ratios of accumulation for [18F]-L: -FMAU, [18F]-D: -FMAU, and [18F]-FLT in H441 cells were 4.15 +/- 1.82, 3.37 +/- 1.19, and 12.94 +/- 4.38, respectively, and the corresponding values in H3255 cells were 1.62 +/- 0.50, 1.96 +/- 0.74, and 1.50 +/- 0.90. CONCLUSIONS [18F]-L: -FMAU may be a useful agent for imaging tumor proliferation in fast-growing human lung cancers by PET.
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Affiliation(s)
- Ryuichi Nishii
- Department of Experimental Diagnostic Imaging, M. D. Anderson Cancer Center, The University of Texas, Box 059, T8.3895, 1515 Holcombe Blvd, Houston, TX 77030, USA
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Toyohara J, Okada M, Toramatsu C, Suzuki K, Irie T. Feasibility studies of 4'-[methyl-(11)C]thiothymidine as a tumor proliferation imaging agent in mice. Nucl Med Biol 2008; 35:67-74. [PMID: 18158945 DOI: 10.1016/j.nucmedbio.2007.10.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 09/05/2007] [Accepted: 10/02/2007] [Indexed: 01/08/2023]
Abstract
This study reports on the radiosynthesis and feasibility studies of 4'-[methyl-(11)C]thiothymidine ([methyl-(11)C]S-dThd) as a tumor proliferation imaging agent. [Methyl-(11)C]S-dThd was synthesized by rapid methylation of corresponding 5-trimethylstannyl- or 5-tributylstannyl-precursor via a palladium-promoted Stille cross-coupling reaction with [(11)C]methyl iodide. The decay-corrected radiochemical yields of [methyl-(11)C]S-dThd synthesized by the corresponding 5-trimethylstannyl-precursor and 5-tributylstannyl-precursor based on [(11)C]CO(2) were 18.9% and 14.5%, respectively. The radiochemical purity of [methyl-(11)C]S-dThd was always greater than 99%. The specific activities of [methyl-(11)C]S-dThd synthesized by the corresponding 5-trimethylstannyl-precursor and 5-tributylstannyl-precursor were 47 GBq/mumol and 121 GBq/mumol, respectively, at the end of the synthesis. The total synthesis time was 30 min after the end of bombardment. The comparison between in vivo distribution of [methyl-(14)C]S-dThd and that of [methyl-(3)H]FLT showed that tracer uptake was comparable in nonproliferating tissues. In contrast, [methyl-(14)C]S-dThd showed significantly higher uptake in proliferating tissues than did [methyl-(3)H]FLT. [Methyl-(11)C]S-dThd uptake levels in five different tumor tissues were well correlated with the DNA synthesis levels determined by [2-(14)C]thymidine DNA incorporation. At 30 min after injection, plasma analysis found 95% of the activity in unmetabolized form. The microPET imaging of the C6 glioma xenograft showed significantly high uptake in the tumor and urinary bladder, followed by the intestine and marrow. Our results demonstrated that the tumor uptake of [methyl-(11)C]S-dThd was higher than that of [methyl-(3)H]FLT and was well correlated with the DNA synthesis level. Consequently, 4'-[methyl-(11)C]thiothymidine has promise for the imaging of tumor cell proliferation by positron emission tomography.
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Affiliation(s)
- Jun Toyohara
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan.
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Tehrani OS, Douglas KA, Lawhorn-Crews JM, Shields AF. Tracking cellular stress with labeled FMAU reflects changes in mitochondrial TK2. Eur J Nucl Med Mol Imaging 2008; 35:1480-8. [PMID: 18265975 DOI: 10.1007/s00259-008-0738-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 01/22/2008] [Indexed: 12/31/2022]
Abstract
PURPOSE Fluoropyrimidines like 1-(2'-deoxy-2'-fluoro-beta-D: -arabinofuranosyl)-thymine (FMAU) and 3'-deoxy-3'-fluorothymidine (FLT) accumulate in tumors and are being used as positron emission tomography tumor-imaging tracers. Proliferating tissues with high thymidine kinase 1 (TK1) activity retain FLT; however, the mechanism of selective accumulation of FMAU in tumors and certain other tissues requires further study. METHODS Retention of [(3)H]FLT and [(3)H]FMAU was measured in prostate cancer cell lines PC3, LNCaP, DU145, and the breast cancer cell line MD-MBA-231, and the tracer metabolites were analyzed by high-performance liquid chromatography (HPLC). FMAU retention, thymidine kinase 2 (TK2) activity, and mitochondrial mass were determined in cells stressed by depleted cell culture medium or by treating with oxidative, reductive, and energy stress, or specific adenosine monophosphate-activated protein kinase activator, or eIF2 inhibitor. TK1 and TK2 activities and mitochondrial mass were determined by FLT phosphorylation, 1-beta-D: -arabinofuranosylthymine (Ara-T) phosphorylation, and flow cytometry, respectively. RESULTS FMAU retention in rapidly proliferating cancer cell lines was five to ten times lower than FLT after 10 min incubation. HPLC analysis of the cellular extracts showed that phosphorylated tracers are the main retained metabolites. Nutritional stress decreased TK1 activity and FLT retention but increased retained FMAU. TK2 inhibition decreased FMAU retention and phosphorylation with negligible effects on FLT. Oxidative, reductive, or energy stress increased FMAU retention and correlated with mitochondrial mass (r (2) = 0.88, p = 0.006). FMAU phosphorylation correlated with increased TK2 activity (r (2) = 0.87, p = 0.0002). CONCLUSION FMAU is preferably phosphorylated by TK2 and can track TK2 activity and mitochondrial mass in cellular stress. FMAU may provide an early marker of treatment effects.
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Affiliation(s)
- Omid S Tehrani
- Karmanos Cancer Institute, Wayne State University, 4100 John R, 4 HWCRC, Detroit, MI 48201-2013, USA
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In vivo measurement of cell proliferation in canine brain tumor using C-11-labeled FMAU and PET. Nucl Med Biol 2008; 35:131-41. [DOI: 10.1016/j.nucmedbio.2007.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 09/04/2007] [Accepted: 09/08/2007] [Indexed: 11/21/2022]
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Buck AK, Kratochwil C, Glatting G, Juweid M, Bommer M, Tepsic D, Vogg ATJ, Mattfeldt T, Neumaier B, Möller P, Reske SN. Early assessment of therapy response in malignant lymphoma with the thymidine analogue [18F]FLT. Eur J Nucl Med Mol Imaging 2007; 34:1775-82. [PMID: 17541585 DOI: 10.1007/s00259-007-0452-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2006] [Accepted: 04/05/2007] [Indexed: 11/28/2022]
Abstract
PURPOSE The aim of this study was to determine whether the thymidine analogue 3'-deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) is adequate for early evaluation of the response of malignant lymphoma to antiproliferative treatment in a mouse xenotransplant model. METHODS Immunodeficient mice bearing a follicular lymphoma xenotransplant were treated with high-dose chemotherapy (cyclophosphamide, n = 10), immunotherapy (CD20 mAb, ibritumomab-tiuxetan, n = 10) or radioimmunotherapy ([(90)Y]CD20 mAb, Zevalin, n = 10). Forty-eight hours after treatment, antiproliferative effects were assessed with [(18)F]FLT. Ninety minutes after i.v. injection of 5-10 MBq [(18)F]FLT, mice were sacrificed and radioactivity within the tumour and normal organs was measured using a gamma counter and calculated as % ID/g. The proliferation fraction in tissue samples derived from treated and untreated tumours was evaluated by Ki-67 immunohistochemistry, which served as the reference for proliferative activity. RESULTS In untreated lymphoma, the mean proliferation fraction was 83.6%. After chemotherapy, the mean proliferation fraction decreased to 39.3% (p = 0.0001), after immunotherapy to 77.6% (p = 0.0078) and after radioimmunotherapy to 78.8% (p = 0.014). In none of the animals was a significant change in tumour size observed. In untreated lymphoma, tumoural [(18)F]FLT uptake was 5.4% ID/g, after chemotherapy it was 1.5% (p = 0.0005), after immunotherapy, 3.9% (non-significant), and after radioimmunotherapy, 5.8% (non-significant). CONCLUSION In a lymphoma xenotransplant model, [(18)F]FLT detects early antiproliferative drug activity before changes in tumour size are visible. These findings further support the use of [(18)F]FLT-PET for imaging early response to treatment in malignant lymphoma.
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Affiliation(s)
- Andreas K Buck
- Department of Nuclear Medicine, University Hospital Ulm, Ulm, Germany.
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Mukhopadhyay U, Pal A, Gelovani JG, Bornmann W, Alauddin MM. Radiosynthesis of 2'-deoxy-2'-[18F]-fluoro-5-methyl-1-beta-L-arabinofuranosyluracil ([18F]-L-FMAU) for PET. Appl Radiat Isot 2007; 65:941-6. [PMID: 17517516 DOI: 10.1016/j.apradiso.2007.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 03/06/2007] [Accepted: 04/02/2007] [Indexed: 10/23/2022]
Abstract
Radiosynthesis of 2'-deoxy-2'-[(18)F]-fluoro-5-methyl-1-beta-L-arabinofuranosyluracil ([(18)F]-L-FMAU) is reported. Compound 1 was synthesized and converted to 2-triflate 2. Compound 3 was prepared from 2 using tetrabutylammonium[(18)F]fluoride, converted to 4, and then coupled with 5. The crude product was hydrolyzed, and purified by HPLC to obtain 7a. The radiochemical yield of [(18)F]-L-FMAU was 26% decay corrected (d.c.) in four runs with radiochemical purity >99% and specific activity 2200 mCi/micromol. The synthesis time was 3.3-3.5h from the end of bombardment (EOB).
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Affiliation(s)
- Uday Mukhopadhyay
- Department of Experimental Diagnostic Imaging, University of Texas M D Anderson Cancer Center, Houston, TX, USA
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Oriuchi N, Higuchi T, Ishikita T, Miyakubo M, Hanaoka H, Iida Y, Endo K. Present role and future prospects of positron emission tomography in clinical oncology. Cancer Sci 2006; 97:1291-7. [PMID: 17052261 PMCID: PMC11158225 DOI: 10.1111/j.1349-7006.2006.00341.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Positron emission tomography (PET) has emerged as a significant molecular imaging technique in clinical oncology and cancer research. PET with (18)F-fluorodeoxyglucose ((18)F-FDG) demonstrates elevated glucose consumption by tumor cells, and is used clinically for the accurate staging and restaging of cancer, planning of radiotherapy, and predicting response or lack of response in the early stages of treatment. Combined PET and computed tomography (PET-CT) provides both functional and morphological information of the disease to allow accurate diagnosis of cancer. PET with new radiotracers such as protein synthesis markers and proliferation markers, as well as hypoxia and receptor-binding agents, will offer patient-specific images in order to yield tailored diagnostic and prognostic information.
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Affiliation(s)
- Noboru Oriuchi
- Department of Diagnostic Radiology and Nuclear Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi 371-8511, Japan.
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Kang KW, Min JJ, Chen X, Gambhir SS. Comparison of [14C]FMAU, [3H]FEAU, [14C]FIAU, and [3H]PCV for monitoring reporter gene expression of wild type and mutant herpes simplex virus type 1 thymidine kinase in cell culture. Mol Imaging Biol 2006; 7:296-303. [PMID: 16041591 DOI: 10.1007/s11307-005-0010-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To assess the optimal reporter probe/reporter gene combination for monitoring herpes simplex virus type 1 thymidine kinase (HSV1-tk) gene expression, we compared the cellular uptake of 1-(2'-fluoro-2'-deoxy-D-arabinofuranosyl)-5-methyluracil (FMAU), 2'-fluoro-2'-deoxyarabinofuranosyl-5-ethyluracil (FEAU), 2'-fluoro-2'-deoxy-beta-D-arabinofuranosyl-5-iodouracil (FIAU) and penciclovir (PCV) in both HSV1-tk and HSV1-sr39tk expressing cells. PROCEDURES For stably transfected cell studies, C6 rat glioma cells, C6 HSV1-tk transfectant, C6 mutant HSV1-sr39tk transfectant, rat Morris hepatoma cells (MH3924A), and MH3924A HSV1-tk transfectant cells were used. For adenoviral infection studies, C6 rat glioma cells were exposed to serial titers of AdCMV-HSV1-tk, AdCMV-HSV1-sr39tk, or AdCMV-fluc for 24 hours. These cells were incubated with [(14)C]FMAU, [(3)H]FEAU, [(14)C]FIAU, and [(3)H]PCV, and cellular uptake of radioactivity was measured. RESULTS [(3)H]FEAU exhibited the highest or second highest accumulation and the most selectivity regardless of the mode of gene transfer for both HSV1-tk and mutant HSV1-sr39tk reporter genes. CONCLUSION This combination of high accumulation and high selectivity for both HSV1-tk and HSV1-sr39tk makes suitably radiolabeled FEAU a promising candidate as a radiotracer for imaging HSV1-tk/HSV1-sr39tk gene expression in living subjects.
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Affiliation(s)
- Keon Wook Kang
- Department of Radiology, Bio-X Program, Stanford University, Stanford, CA 94305, USA
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