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Zhou R, Choi H, Cao J, Pantel A, Gupta M, Lee HS, Mankoff D. 18F-Fluciclovine PET Imaging of Glutaminase Inhibition in Breast Cancer Models. J Nucl Med 2023; 64:131-136. [PMID: 35772960 PMCID: PMC9841257 DOI: 10.2967/jnumed.122.264152] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 06/21/2022] [Accepted: 06/21/2022] [Indexed: 01/28/2023] Open
Abstract
Aggressive cancers such as triple-negative breast cancer (TNBC) avidly metabolize glutamine as a feature of their malignant phenotype. The conversion of glutamine to glutamate by the glutaminase enzyme represents the first and rate-limiting step of this pathway and a target for drug development. Indeed, a novel glutaminase inhibitor (GLSi) has been developed and tested in clinical trials but with limited success, suggesting the potential for a biomarker to select patients who could benefit from this novel therapy. Here, we studied a nonmetabolized amino acid analog, 18F-fluciclovine, as a PET imaging biomarker for detecting the pharmacodynamic response to GLSi. Methods: Uptake of 18F-fluciclovine into human breast cancer cells was studied in the presence and absence of inhibitors of glutamine transporters and GLSi. To allow 18F-fluciclovine PET to be performed on mice, citrate in the tracer formulation is replaced by phosphate-buffered saline. Mice bearing triple-negative breast cancer (TNBC) xenografts (HCC38, HCC1806, and MBA-MD-231) and estrogen receptor-positive breast cancer xenografts (MCF-7) were imaged with dynamic PET at baseline and after a 2-d treatment of GLSi (CB839) or vehicle. Kinetic analysis suggested reversible uptake of the tracer, and the distribution volume (VD) of 18F-fluciclovine was estimated by Logan plot analysis. Results: Our data showed that cellular uptake of 18F-fluciclovine is mediated by glutamine transporters. A significant increase in VD was observed after CB839 treatment in TNBC models exhibiting high glutaminase activity (HCC38 and HCC1806) but not in TNBC or MCF-7 exhibiting low glutaminase. Changes in VD were corroborated with changes in GLS activity measured in tumors treated with CB839 versus vehicle, as well as with changes in VD of 18F-(2S,R4)-fluoroglutamine, which we previously validated as a measure of cellular glutamine pool size. A moderate, albeit significant, decrease in 18F-FDG PET signal was observed in HCC1806 tumors after CB839 treatment. Conclusion: 18F-fluciclovine PET has potential to serve as a clinically translatable pharmacodynamic biomarker of GLSi.
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Affiliation(s)
- Rong Zhou
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | | | | | | | | | - David Mankoff
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
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Iqbal M, Karim A, Ali S, Nawaz Tahir M, Sohail M. Synthesis, characterization, structural elucidation, electrochemistry, DNA binding study, micellization behaviour and antioxidant activity of the Cu(II) carboxylate complexes. Polyhedron 2020. [DOI: 10.1016/j.poly.2019.114310] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Rosenberg AJ, Nickels ML, Schulte ML, Manning HC. Automated radiosynthesis of 5-[ 11C]l-glutamine, an important tracer for glutamine utilization. Nucl Med Biol 2018; 67:10-14. [PMID: 30359787 DOI: 10.1016/j.nucmedbio.2018.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/24/2018] [Accepted: 09/29/2018] [Indexed: 12/16/2022]
Abstract
INTRODUCTION The natural amino acid l-Glutamine (Gln) is essential for both cell growth and proliferation. In addition to glucose, cancer cells utilize Gln as a carbon source for ATP production, biosynthesis, and as a defense against reactive oxygen species. The utilization of [11C]Gln has been previously reported as a biomarker for tissues with an elevated demand for Gln, however, the previous reports for the preparation of [11C]Gln were found to be lacking several crucial aspects necessary for transition to human production. Namely, the presence of unreacted precursor and the use of non-commercialized, custom built, reaction platforms. Herein, we report the development and utilization of methodology for the automated production of [11C]Gln that meets institutional criteria for human use. METHODS The preparation of [11C]Gln was carried out on the GE FX2N platform. Briefly, after trapping of [11C]HCN with a solution of CsHCO3 in DMF, the [11C]CsCN was reacted with a commercially available precursor. This intermediate was then purified by HPLC and deprotected/hydrolyzed under acidic conditions. Following pH adjustment, the product was filtered to give the desired [11C]Gln as a sterile injectable. The resulting product was then analyzed for quality assurance. RESULTS Automated production by this method reliably provides over 3.7 GBq (100 mCi) of [11C]Gln. The resulting final drug product was found to have a >99% radiochemical purity, <5% of D-Gln present, no detectable impurities, and the total preparation time was roughly 45 min from the end-of-bombardment. CONCLUSIONS A fast, reliable and efficient automated radiosynthesis was developed using a commercially available module. Purifications used throughout allow for both a radiochemically and chemically pure final product solution of [11C]Gln.
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Affiliation(s)
- Adam J Rosenberg
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt University Institute for Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael L Nickels
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt University Institute for Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael L Schulte
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt University Institute for Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - H Charles Manning
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt University Institute for Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA.
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Hariharan VA, Denton TT, Paraszcszak S, McEvoy K, Jeitner TM, Krasnikov BF, Cooper AJL. The Enzymology of 2-Hydroxyglutarate, 2-Hydroxyglutaramate and 2-Hydroxysuccinamate and Their Relationship to Oncometabolites. BIOLOGY 2017; 6:biology6020024. [PMID: 28358347 PMCID: PMC5485471 DOI: 10.3390/biology6020024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/10/2017] [Accepted: 03/13/2017] [Indexed: 12/17/2022]
Abstract
Many enzymes make "mistakes". Consequently, repair enzymes have evolved to correct these mistakes. For example, lactate dehydrogenase (LDH) and mitochondrial malate dehydrogenase (mMDH) slowly catalyze the reduction of 2-oxoglutarate (2-OG) to the oncometabolite l-2-hydroxyglutarate (l-2-HG). l-2-HG dehydrogenase corrects this error by converting l-2-HG to 2-OG. LDH also catalyzes the reduction of the oxo group of 2-oxoglutaramate (2-OGM; transamination product of l-glutamine). We show here that human glutamine synthetase (GS) catalyzes the amidation of the terminal carboxyl of both the l- and d- isomers of 2-HG. The reaction of 2-OGM with LDH and the reaction of l-2-HG with GS generate l-2-hydroxyglutaramate (l-2-HGM). We also show that l-2-HGM is a substrate of human ω-amidase. The product (l-2-HG) can then be converted to 2-OG by l-2-HG dehydrogenase. Previous work showed that 2-oxosuccinamate (2-OSM; transamination product of l-asparagine) is an excellent substrate of LDH. Finally, we also show that human ω-amidase converts the product of this reaction (i.e., l-2-hydroxysuccinamate; l-2-HSM) to l-malate. Thus, ω-amidase may act together with hydroxyglutarate dehydrogenases to repair certain "mistakes" of GS and LDH. The present findings suggest that non-productive pathways for nitrogen metabolism occur in mammalian tissues in vivo. Perturbations of these pathways may contribute to symptoms associated with hydroxyglutaric acidurias and to tumor progression. Finally, methods for the synthesis of l-2-HGM and l-2-HSM are described that should be useful in determining the roles of ω-amidase/4- and 5-C compounds in photorespiration in plants.
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Affiliation(s)
- Vivek A Hariharan
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Travis T Denton
- Department of Pharmaceutical Sciences, Washington State University, College of Pharmacy, Spokane, WA 99210-1495, USA.
| | - Sarah Paraszcszak
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Kyle McEvoy
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Thomas M Jeitner
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Boris F Krasnikov
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10590, USA.
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