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Gandhi R, Cawthorne C, Craggs LJL, Wright JD, Domarkas J, He P, Koch-Paszkowski J, Shires M, Scarsbrook AF, Archibald SJ, Tsoumpas C, Bailey MA. Cell proliferation detected using [ 18F]FLT PET/CT as an early marker of abdominal aortic aneurysm. J Nucl Cardiol 2021; 28:1961-1971. [PMID: 31741324 PMCID: PMC8648642 DOI: 10.1007/s12350-019-01946-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 10/17/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Abdominal aortic aneurysm (AAA) is a focal aortic dilatation progressing towards rupture. Non-invasive AAA-associated cell proliferation biomarkers are not yet established. We investigated the feasibility of the cell proliferation radiotracer, fluorine-18-fluorothymidine ([18F]FLT) with positron emission tomography/computed tomography (PET/CT) in a progressive pre-clinical AAA model (angiotensin II, AngII infusion). METHODS AND RESULTS Fourteen-week-old apolipoprotein E-knockout (ApoE-/-) mice received saline or AngII via osmotic mini-pumps for 14 (n = 7 and 5, respectively) or 28 (n = 3 and 4, respectively) days and underwent 90-minute dynamic [18F]FLT PET/CT. Organs were harvested from independent cohorts for gamma counting, ultrasound scanning, and western blotting. [18F]FLT uptake was significantly greater in 14- (n = 5) and 28-day (n = 3) AAA than in saline control aortae (n = 5) (P < 0.001), which reduced between days 14 and 28. Whole-organ gamma counting confirmed greater [18F]FLT uptake in 14-day AAA (n = 9) compared to saline-infused aortae (n = 4) (P < 0.05), correlating positively with aortic volume (r = 0.71, P < 0.01). Fourteen-day AAA tissue showed increased expression of thymidine kinase-1, equilibrative nucleoside transporter (ENT)-1, ENT-2, concentrative nucleoside transporter (CNT)-1, and CNT-3 than 28-day AAA and saline control tissues (n = 3 each) (all P < 0.001). CONCLUSIONS [18F]FLT uptake is increased during the active growth phase of the AAA model compared to saline control mice and late-stage AAA.
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Affiliation(s)
- Richa Gandhi
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, 8.49c Worsley Building, Clarendon Way, Leeds, LS2 9NL, United Kingdom
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, United Kingdom
| | - Christopher Cawthorne
- Department of Biomedical Science, PET Research Centre, University of Hull, Hull, United Kingdom
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Lucinda J L Craggs
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, 8.49c Worsley Building, Clarendon Way, Leeds, LS2 9NL, United Kingdom
| | - John D Wright
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, 8.49c Worsley Building, Clarendon Way, Leeds, LS2 9NL, United Kingdom
- Experimental & PreClinical Imaging Facility (ePIC), School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Juozas Domarkas
- Department of Biomedical Science, PET Research Centre, University of Hull, Hull, United Kingdom
| | - Ping He
- Department of Biomedical Science, PET Research Centre, University of Hull, Hull, United Kingdom
| | - Joanna Koch-Paszkowski
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, 8.49c Worsley Building, Clarendon Way, Leeds, LS2 9NL, United Kingdom
- Experimental & PreClinical Imaging Facility (ePIC), School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Michael Shires
- Leeds Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom
| | - Andrew F Scarsbrook
- Leeds Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom
| | - Stephen J Archibald
- Department of Biomedical Science, PET Research Centre, University of Hull, Hull, United Kingdom
| | - Charalampos Tsoumpas
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, 8.49c Worsley Building, Clarendon Way, Leeds, LS2 9NL, United Kingdom.
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Invicro, London, United Kingdom.
| | - Marc A Bailey
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, 8.49c Worsley Building, Clarendon Way, Leeds, LS2 9NL, United Kingdom
- The Leeds Vascular Institute, Leeds General Infirmary, Great George Street, Leeds, United Kingdom
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2
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Krys D, Hamann I, Wuest M, Wuest F. Effect of hypoxia on human equilibrative nucleoside transporters hENT1 and hENT2 in breast cancer. FASEB J 2019; 33:13837-13851. [PMID: 31601121 DOI: 10.1096/fj.201900870rr] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Elevated proliferation rates in cancer can be visualized with positron emission tomography (PET) using 3'-deoxy-3'-l-[18F]fluorothymidine ([18F]FLT). This study investigates whether [18F]FLT transport proteins are regulated through hypoxia. Expression and function of human equilibrative nucleoside transporter (hENT)-1, hENT2, and thymidine kinase 1 (TK1) were studied under normoxic and hypoxic conditions, and assessed with [18F]FLT-PET in estrogen receptor positive (ER+)-MCF7, triple-negative MDA-MB231 breast cancer (BC) cells, and MCF10A cells (human mammary epithelial cells). Functional involvement of hENT2 [18F]FLT transport was demonstrated in all cell lines. In vitro [18F]FLT uptake was higher in MDA-MB231 than in MCF7: 242 ± 9 vs. 147 ± 18% radioactivity/mg protein after 60 min under normoxia. Hypoxia showed no significant change in radiotracer uptake. Protein analysis revealed increased hENT1 (P < 0.0963) in MDA-MB231. Hypoxia did not change expression of either hENT1, hENT2, or TK1. In vitro inhibition experiments suggested involvement of hENT1, hENT2, and human concentrative nucleoside transporters during [18F]FLT uptake into all cell lines. In vivo PET imaging revealed comparable tumor uptake in MCF7 and MDA-MB231 tumors over 60 min, reaching standardized uptake values of 0.96 ± 0.05 vs. 0.89 ± 0.08 (n = 3). Higher hENT1 expression in MDA-MB231 seems to drive nucleoside transport, whereas TK1 expression in MCF7 seems responsible for comparable [18F]FLT retention in ER+ tumors. Our study demonstrates that hypoxia does not significantly affect nucleoside transport as tested with [18F]FLT in BC.-Krys, D., Hamann, I., Wuest, M., Wuest, F. Effect of hypoxia on human equilibrative nucleoside transporters hENT1 and hENT2 in breast cancer.
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Affiliation(s)
- Daniel Krys
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Ingrit Hamann
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Melinda Wuest
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.,Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, Alberta, Canada
| | - Frank Wuest
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.,Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, Alberta, Canada
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Rehan S, Shahid S, Salminen TA, Jaakola VP, Paavilainen VO. Current Progress on Equilibrative Nucleoside Transporter Function and Inhibitor Design. SLAS DISCOVERY 2019; 24:953-968. [PMID: 31503511 DOI: 10.1177/2472555219870123] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Physiological nucleosides are used for the synthesis of DNA, RNA, and ATP in the cell and serve as universal mammalian signaling molecules that regulate physiological processes such as vasodilation and platelet aggregation by engaging with cell surface receptors. The same pathways that allow uptake of physiological nucleosides mediate the cellular import of synthetic nucleoside analogs used against cancer, HIV, and other viral diseases. Physiological nucleosides and nucleoside drugs are imported by two families of nucleoside transporters: the SLC28 concentrative nucleoside transporters (CNTs) and SLC29 equilibrative nucleoside transporters (ENTs). The four human ENT paralogs are expressed in distinct tissues, localize to different subcellular sites, and transport a variety of different molecules. Here we provide an overview of the known structure-function relationships of the ENT family with a focus on ligand binding and transport in the context of a new hENT1 homology model. We provide a generic residue numbering system for the different ENTs to facilitate the interpretation of mutational data produced using different ENT homologs. The discovery of paralog-selective small-molecule modulators is highly relevant for the design of new therapies and for uncovering the functions of poorly characterized ENT family members. Here, we discuss recent developments in the discovery of new paralog-selective small-molecule ENT inhibitors, including new natural product-inspired compounds. Recent progress in the ability to heterologously produce functional ENTs will allow us to gain insight into the structure and functions of different ENT family members as well as the rational discovery of highly selective inhibitors.
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Affiliation(s)
- Shahid Rehan
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,HiLIFE, University of Helsinki, Helsinki, Finland
| | - Saman Shahid
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Tiina A Salminen
- Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Veli-Pekka Jaakola
- Chemical Biology & Therapeutics, Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Ville O Paavilainen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,HiLIFE, University of Helsinki, Helsinki, Finland
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4
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Ashek A, Spruijt OA, Harms HJ, Lammertsma AA, Cupitt J, Dubois O, Wharton J, Dabral S, Pullamsetti SS, Huisman MC, Frings V, Boellaard R, de Man FS, Botros L, Jansen S, Vonk Noordegraaf A, Wilkins MR, Bogaard HJ, Zhao L. 3'-Deoxy-3'-[18F]Fluorothymidine Positron Emission Tomography Depicts Heterogeneous Proliferation Pathology in Idiopathic Pulmonary Arterial Hypertension Patient Lung. Circ Cardiovasc Imaging 2019; 11:e007402. [PMID: 30354494 DOI: 10.1161/circimaging.117.007402] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Pulmonary vascular cell hyperproliferation is characteristic of pulmonary vascular remodeling in pulmonary arterial hypertension. A noninvasive imaging biomarker is needed to track the pathology and assess the response to novel treatments targeted at resolving the structural changes. Here, we evaluated the application of radioligand 3'-deoxy-3'-[18F]-fluorothymidine (18FLT) using positron emission tomography. METHODS AND RESULTS We performed dynamic 18FLT positron emission tomography in 8 patients with idiopathic pulmonary arterial hypertension (IPAH) and applied in-depth kinetic analysis with a reversible 2-compartment 4k model. Our results show significantly increased lung 18FLT phosphorylation (k3) in patients with IPAH compared with nonpulmonary arterial hypertension controls (0.086±0.034 versus 0.054±0.009 min-1; P<0.05). There was heterogeneity in the lung 18FLT signal both between patients with IPAH and within the lungs of each patient, compatible with histopathologic reports of lungs from patients with IPAH. Consistent with 18FLT positron emission tomographic data, TK1 (thymidine kinase 1) expression was evident in the remodeled vessels in IPAH patient lung. In addition, hyperproliferative pulmonary vascular fibroblasts isolated from patients with IPAH exhibited upregulated expression of TK1 and the thymidine transporter, ENT1 (equilibrative nucleoside transporter 1). In the monocrotaline and SuHx (Sugen hypoxia) rat pulmonary arterial hypertension models, increased lung 18FLT uptake was strongly associated with peripheral pulmonary vascular muscularization and the proliferation marker, Ki-67 score, together with prominent TK1 expression in remodeled vessels. Importantly, lung 18FLT uptake was attenuated by 2 antiproliferative treatments: dichloroacetate and the tyrosine kinase inhibitor, imatinib. CONCLUSIONS Dynamic 18FLT positron emission tomography imaging can be used to report hyperproliferation in pulmonary hypertension and merits further study to evaluate response to treatment in patients with IPAH.
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Affiliation(s)
- Ali Ashek
- Center for Pharmacology and Therapeutics, Experimental Medicine, Hammersmith Hospital, Imperial College London, United Kingdom (A.A., J.C., O.D., J.W., M.R.W., L.Z.)
| | - Onno A Spruijt
- Department of Pulmonary Medicine (O.A.S., H.J.H., F.S.d.M., L.B., S.J., A.V.N., H.J.B.)
| | - Hendrik J Harms
- Department of Pulmonary Medicine (O.A.S., H.J.H., F.S.d.M., L.B., S.J., A.V.N., H.J.B.)
| | - Adriaan A Lammertsma
- Department of Radiology and Nuclear Medicine (A.A.L., M.C.H., V.F., R.B., F.S.d.M.), VU University Medical Center, Amsterdam, the Netherlands
| | - John Cupitt
- Center for Pharmacology and Therapeutics, Experimental Medicine, Hammersmith Hospital, Imperial College London, United Kingdom (A.A., J.C., O.D., J.W., M.R.W., L.Z.)
| | - Olivier Dubois
- Center for Pharmacology and Therapeutics, Experimental Medicine, Hammersmith Hospital, Imperial College London, United Kingdom (A.A., J.C., O.D., J.W., M.R.W., L.Z.)
| | - John Wharton
- Center for Pharmacology and Therapeutics, Experimental Medicine, Hammersmith Hospital, Imperial College London, United Kingdom (A.A., J.C., O.D., J.W., M.R.W., L.Z.)
| | - Swati Dabral
- Max-Planck Institute for Heart and Lung Research, University of Giessen and Marburg Lung Center, German Center for Lung Research, Bad Nauheim (S.D., S.S.P.)
| | - Soni Savai Pullamsetti
- Max-Planck Institute for Heart and Lung Research, University of Giessen and Marburg Lung Center, German Center for Lung Research, Bad Nauheim (S.D., S.S.P.)
| | - Marc C Huisman
- Department of Radiology and Nuclear Medicine (A.A.L., M.C.H., V.F., R.B., F.S.d.M.), VU University Medical Center, Amsterdam, the Netherlands
| | - Virginie Frings
- Department of Radiology and Nuclear Medicine (A.A.L., M.C.H., V.F., R.B., F.S.d.M.), VU University Medical Center, Amsterdam, the Netherlands
| | - Ronald Boellaard
- Department of Radiology and Nuclear Medicine (A.A.L., M.C.H., V.F., R.B., F.S.d.M.), VU University Medical Center, Amsterdam, the Netherlands
| | - Frances S de Man
- Department of Pulmonary Medicine (O.A.S., H.J.H., F.S.d.M., L.B., S.J., A.V.N., H.J.B.).,Department of Radiology and Nuclear Medicine (A.A.L., M.C.H., V.F., R.B., F.S.d.M.), VU University Medical Center, Amsterdam, the Netherlands
| | - Lisa Botros
- Department of Pulmonary Medicine (O.A.S., H.J.H., F.S.d.M., L.B., S.J., A.V.N., H.J.B.)
| | - Samara Jansen
- Department of Pulmonary Medicine (O.A.S., H.J.H., F.S.d.M., L.B., S.J., A.V.N., H.J.B.)
| | | | - Martin R Wilkins
- Center for Pharmacology and Therapeutics, Experimental Medicine, Hammersmith Hospital, Imperial College London, United Kingdom (A.A., J.C., O.D., J.W., M.R.W., L.Z.)
| | - Harm J Bogaard
- Department of Pulmonary Medicine (O.A.S., H.J.H., F.S.d.M., L.B., S.J., A.V.N., H.J.B.)
| | - Lan Zhao
- Center for Pharmacology and Therapeutics, Experimental Medicine, Hammersmith Hospital, Imperial College London, United Kingdom (A.A., J.C., O.D., J.W., M.R.W., L.Z.)
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5
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Schelhaas S, Heinzmann K, Honess DJ, Smith DM, Keen H, Heskamp S, Witney TH, Besret L, Doblas S, Griffiths JR, Aboagye EO, Jacobs AH. 3'-Deoxy-3'-[ 18F]Fluorothymidine Uptake Is Related to Thymidine Phosphorylase Expression in Various Experimental Tumor Models. Mol Imaging Biol 2018; 20:194-199. [PMID: 28971330 DOI: 10.1007/s11307-017-1125-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE We recently reported that high thymidine phosphorylase (TP) expression is accompanied by low tumor thymidine concentration and high 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT) uptake in four untreated lung cancer xenografts. Here, we investigated whether this relationship also holds true for a broader range of tumor models. PROCEDURES Lysates from n = 15 different tumor models originating from n = 6 institutions were tested for TP and thymidylate synthase (TS) expression using western blots. Results were correlated to [18F]FLT accumulation in the tumors as determined by positron emission tomography (PET) measurements in the different institutions and to previously published thymidine concentrations. RESULTS Expression of TP correlated positively with [18F]FLT SUVmax (ρ = 0.549, P < 0.05). Furthermore, tumors with high TP levels possessed lower levels of thymidine (ρ = - 0.939, P < 0.001). CONCLUSIONS In a broad range of tumors, [18F]FLT uptake as measured by PET is substantially influenced by TP expression and tumor thymidine concentrations. These data strengthen the role of TP as factor confounding [18F]FLT uptake.
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Affiliation(s)
- Sonja Schelhaas
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Waldeyerstr. 15, 48149, Münster, Germany
| | - Kathrin Heinzmann
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- Comprehensive Cancer Imaging Centre, Imperial College London, London, UK
| | - Davina J Honess
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | | | - Heather Keen
- PHB Imaging Group, AstraZeneca, Alderley Park, Macclesfield, UK
| | - Sandra Heskamp
- Department of Radiology and Nuclear Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Timothy H Witney
- Comprehensive Cancer Imaging Centre, Imperial College London, London, UK
- UCL Centre for Advanced Biomedical Imaging, University College London, London, UK
| | | | | | - John R Griffiths
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Eric O Aboagye
- Comprehensive Cancer Imaging Centre, Imperial College London, London, UK
| | - Andreas H Jacobs
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Waldeyerstr. 15, 48149, Münster, Germany.
- Department of Geriatric Medicine, Johanniter Hospital, Bonn, Germany.
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Chen X, Yang Y, Berger I, Khalid U, Patel A, Cai J, Farwell MD, Langer C, Aggarwal C, Albelda SM, Katz SI. Early detection of pemetrexed-induced inhibition of thymidylate synthase in non-small cell lung cancer with FLT-PET imaging. Oncotarget 2018; 8:24213-24223. [PMID: 27655645 PMCID: PMC5421841 DOI: 10.18632/oncotarget.12085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 07/13/2016] [Indexed: 11/25/2022] Open
Abstract
Inhibition of thymidylate synthase (TS) results in a transient flare in DNA thymidine salvage pathway activity measurable with FLT ([18F]thymidine)-positron emission tomography (PET). Here we characterize this imaging strategy for potential clinical translation in non-small cell lung cancer (NSCLC). Since pemetrexed acts by inhibiting TS, we defined the kinetics of increases in thymidine salvage pathway mediated by TS inhibition following treatment with pemetrexed in vitro. Next, using a mouse model of NSCLC, we validated the kinetics of the pemetrexed-mediated flare in thymidine salvage pathway activity in vivo using FLT-PET imaging. Finally, we translated our findings into a proof-of-principle clinical trial of FLT-PET in a human NSCLC patient. In NSCLC cells in vitro, we identified a burst in pemetrexed-mediated thymidine salvage pathway activity, assessed by 3H-thymidine assays, thymidine kinase 1 (TK1) expression, and equilibrative nucleoside transporter 1 (ENT1) mobilization to the cell membrane, that peaked at 2hrs. This 2hr time-point was also optimal for FLT-PET imaging of pemetrexed-mediated TS inhibition in murine xenograft tumors and was demonstrated to be feasible in a NSCLC patient. FLT-PET imaging of pemetrexed-induced TS inhibition is optimal at 2hrs from therapy start; this timing is feasible in human clinical trials.
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Affiliation(s)
- Xiao Chen
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.,Department of Radiology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yizeng Yang
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Ian Berger
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Urooj Khalid
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Akash Patel
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Jenny Cai
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Michael D Farwell
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Corey Langer
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Charu Aggarwal
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Steven M Albelda
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sharyn I Katz
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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7
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Ponto LLB, Huang J, Walsh SA, Acevedo MR, Mundt C, Sunderland J, Donovan M. Demonstration of Nucleoside Transporter Activity in the Nose-to-Brain Distribution of [ 18F]Fluorothymidine Using PET Imaging. AAPS JOURNAL 2017; 20:16. [PMID: 29218445 DOI: 10.1208/s12248-017-0158-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/21/2017] [Indexed: 12/17/2022]
Abstract
To evaluate the role of nucleoside transporters in the nose-to-brain uptake of [18F]fluorothymidine (FLT), an equilibrative nucleoside transporter (ENT1,2) and concentrative nucleoside transporter (CNT1-3) substrate, using PET to measure local tissue concentrations. Anesthetized Sprague-Dawley rats were administered FLT by intranasal (IN) instillation or tail-vein injection (IV). NBMPR (nitrobenzylmercaptopurine riboside), an ENT1 inhibitor, was administered either IN or intraperitoneally (IP). Dynamic PET imaging was performed for up to 40 min. A CT was obtained for anatomical co-registration and attenuation correction. Time-activity curves (TACs) were generated for the olfactory bulb (OB) and remaining brain, and the area-under-the-curve (AUC) for each TAC was calculated to determine the total tissue exposure of FLT. FLT concentrations were higher in the OB than in the rest of the brain following IN administration. IP administration of NBMPR resulted in increased OB and brain FLT exposure following both IN and IV administration, suggesting that NBMPR decreases the clearance rate of FLT from the brain. When FLT and NBMPR were co-administered IN, there was a decrease in the OB AUC while an increase in the brain AUC was observed. The decrease in OB exposure was likely the result of inhibition of ENT1 uptake activity in the nose-to-brain transport pathway. FLT distribution patterns show that nucleoside transporters, including ENT1, play a key role in the distribution of transporter substrates between the nasal cavity and the brain via the OB.
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Affiliation(s)
- Laura L Boles Ponto
- Roy J. and Lucille A. Carver College of Medicine, Department of Radiology, University of Iowa, Iowa City, Iowa, USA. .,PET Imaging Center, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA.
| | - Jiangeng Huang
- College of Pharmacy, Division of Pharmaceutics and Translational Therapeutics, University of Iowa, Iowa City, Iowa, USA.,Department of Pharmaceutics, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Susan A Walsh
- Roy J. and Lucille A. Carver College of Medicine, Department of Radiology, University of Iowa, Iowa City, Iowa, USA
| | - Michael R Acevedo
- Roy J. and Lucille A. Carver College of Medicine, Department of Radiology, University of Iowa, Iowa City, Iowa, USA
| | - Christine Mundt
- Roy J. and Lucille A. Carver College of Medicine, Department of Radiology, University of Iowa, Iowa City, Iowa, USA.,PET Imaging Center, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
| | - John Sunderland
- Roy J. and Lucille A. Carver College of Medicine, Department of Radiology, University of Iowa, Iowa City, Iowa, USA.,PET Imaging Center, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
| | - Maureen Donovan
- College of Pharmacy, Division of Pharmaceutics and Translational Therapeutics, University of Iowa, Iowa City, Iowa, USA
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8
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Chen X, Yang Y, Katz S. Early detection of thymidylate synthase resistance in non-small cell lung cancer with FLT-PET imaging. Oncotarget 2017; 8:82705-82713. [PMID: 29137296 PMCID: PMC5669922 DOI: 10.18632/oncotarget.19751] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 06/01/2017] [Indexed: 11/25/2022] Open
Abstract
Introduction Inhibition of thymidylate synthase (TS) results in a transient compensatory "flare" in thymidine salvage pathway activity measureable with 18F-thymidine (FLT)- positron emission tomography (PET) at 2hrs. of therapy which may predict non-small cell lung cancer (NSCLC) sensitivity to TS inhibition. Materials and Methods Resistance to TS inhibition by pemetrexed was induced in NSCLC cell lines H460 and H1299 through TS overexpression. TS overexpression was confirmed with RT-PCR and Western blotting and pemetrexed resistance confirmed with IC50 assays. The presence of a pemetrexed-induced thymidine salvage pathway "flare" was then measured using 3H-thymidine in both pemetrexed sensitive (H460 and H1299) and resistant (H460R, H1299R, CALU-6, H522, H650, H661, H820, H1838) lines in vitro, and validated with FLT-PET in vivo using H460 and H460R xenografts. Results Overexpression of TS induced pemetrexed resistance with IC50 for H460, H1299, H460R and H1299R measured as 0.141 μM, 0.656 μM, 22.842 μM, 213.120 μM, respectively. Thymidine salvage pathway 3H-thymidine "flare" was observed following pemetrexed in H460 and H1299 but not H460R, H1299R, CALU-6, H522, H650, H661, H820 or H1838 in vitro. Similarly, a FLT "flare" was observed in vivo following pemetrexed therapy in H460 but not H460R tumor-bearing xenografts. Conclusions Imaging of TS inhibition is predictive of NSCLC sensitivity to pemetrexed.
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Affiliation(s)
- Xiao Chen
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.,Department of Radiology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yizeng Yang
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sharyn Katz
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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Heskamp S, Heijmen L, Gerrits D, Molkenboer-Kuenen JDM, Ter Voert EGW, Heinzmann K, Honess DJ, Smith DM, Griffiths JR, Doblas S, Sinkus R, Laverman P, Oyen WJG, Heerschap A, Boerman OC. Response Monitoring with [ 18F]FLT PET and Diffusion-Weighted MRI After Cytotoxic 5-FU Treatment in an Experimental Rat Model for Colorectal Liver Metastases. Mol Imaging Biol 2017; 19:540-549. [PMID: 27798786 PMCID: PMC5498638 DOI: 10.1007/s11307-016-1021-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
PURPOSE The aim of the study was to investigate the potential of diffusion-weighted magnetic resonance imaging (DW-MRI) and 3'-dexoy-3'-[18F]fluorothymidine ([18F]FLT) positron emission tomography (PET) as early biomarkers of treatment response of 5-fluorouracil (5-FU) in a syngeneic rat model of colorectal cancer liver metastases. PROCEDURES Wag/Rij rats with intrahepatic syngeneic CC531 tumors were treated with 5-FU (15, 30, or 60 mg/kg in weekly intervals). Before treatment and at days 1, 3, 7, and 14 after treatment rats underwent DW-MRI and [18F]FLT PET. Tumors were analyzed immunohistochemically for Ki67, TK1, and ENT1 expression. RESULTS 5-FU inhibited the growth of CC531 tumors in a dose-dependent manner. Immunohistochemical analysis did not show significant changes in Ki67, TK1, and ENT1 expression. However, [18F]FLT SUVmean and SUVmax were significantly increased at days 4 and 7 after treatment with 5-FU (60 mg/kg) and returned to baseline at day 14 (SUVmax at days -1, 4, 7, and 14 was 1.1 ± 0.1, 2.3 ± 0.5, 2.3 ± 0.6, and 1.5 ± 0.4, respectively). No changes in [18F]FLT uptake were observed in the nontreated animals. Furthermore, the apparent diffusion coefficient (ADCmean) did not change in 5-FU-treated rats compared to untreated rats. CONCLUSION This study suggests that 5-FU treatment induces a flare in [18F]FLT uptake of responsive CC531 tumors in the liver, while the ADCmean did not change significantly. Future studies in larger groups are warranted to further investigate whether [18F]FLT PET can discriminate between disease progression and treatment response.
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Affiliation(s)
- Sandra Heskamp
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Linda Heijmen
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Danny Gerrits
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Edwin G W Ter Voert
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kathrin Heinzmann
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Davina J Honess
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | | | - John R Griffiths
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Sabrina Doblas
- LBI, CRI - UMR 1149 Inserm, Université Paris Diderot, Paris, France
| | - Ralph Sinkus
- BHF Centre of Excellence, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London, SE1 7EH, UK
| | - Peter Laverman
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wim J G Oyen
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Otto C Boerman
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
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10
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Clinical overview of the current state and future applications of positron emission tomography in bone and soft tissue sarcoma. Clin Transl Imaging 2017. [DOI: 10.1007/s40336-017-0236-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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11
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Schelhaas S, Heinzmann K, Bollineni VR, Kramer GM, Liu Y, Waterton JC, Aboagye EO, Shields AF, Soloviev D, Jacobs AH. Preclinical Applications of 3'-Deoxy-3'-[ 18F]Fluorothymidine in Oncology - A Systematic Review. Theranostics 2017; 7:40-50. [PMID: 28042315 PMCID: PMC5196884 DOI: 10.7150/thno.16676] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/16/2016] [Indexed: 11/05/2022] Open
Abstract
The positron emission tomography (PET) tracer 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT) has been proposed to measure cell proliferation non-invasively in vivo. Hence, it should provide valuable information for response assessment to tumor therapies. To date, [18F]FLT uptake has found limited use as a response biomarker in clinical trials in part because a better understanding is needed of the determinants of [18F]FLT uptake and therapy-induced changes of its retention in the tumor. In this systematic review of preclinical [18F]FLT studies, comprising 174 reports, we identify the factors governing [18F]FLT uptake in tumors, among which thymidine kinase 1 plays a primary role. The majority of publications (83 %) report that decreased [18F]FLT uptake reflects the effects of anticancer therapies. 144 times [18F]FLT uptake was related to changes in proliferation as determined by ex vivo analyses. Of these approaches, 77 % describe a positive relation, implying a good concordance of tracer accumulation and tumor biology. These preclinical data indicate that [18F]FLT uptake holds promise as an imaging biomarker for response assessment in clinical studies. Understanding of the parameters which influence cellular [18F]FLT uptake and retention as well as the mechanism of changes induced by therapy is essential for successful implementation of this PET tracer. Hence, our systematic review provides the background for the use of [18F]FLT in future clinical studies.
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Affiliation(s)
- Sonja Schelhaas
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | | | - Vikram R Bollineni
- European Organization for Research and Treatment of Cancer Headquarters, Brussels, Belgium
| | - Gerbrand M Kramer
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Yan Liu
- European Organization for Research and Treatment of Cancer Headquarters, Brussels, Belgium
| | | | - Eric O Aboagye
- Comprehensive Cancer Imaging Centre, Imperial College London, UK
| | - Anthony F Shields
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, Michigan, USA
| | - Dmitry Soloviev
- Cancer Research UK Cambridge Institute, University of Cambridge, UK
| | - Andreas H Jacobs
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany.; Department of Geriatric Medicine, Johanniter Hospital, Bonn, Germany
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12
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Schelhaas S, Held A, Bäumer N, Viel T, Hermann S, Müller-Tidow C, Jacobs AH. Preclinical Evidence That 3′-Deoxy-3′-[18F]Fluorothymidine PET Can Visualize Recovery of Hematopoiesis after Gemcitabine Chemotherapy. Cancer Res 2016; 76:7089-7095. [DOI: 10.1158/0008-5472.can-16-1478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/19/2016] [Accepted: 10/06/2016] [Indexed: 11/16/2022]
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13
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Osgood CL, Tantawy MN, Maloney N, Madaj ZB, Peck A, Boguslawski E, Jess J, Buck J, Winn ME, Manning HC, Grohar PJ. 18F-FLT Positron Emission Tomography (PET) is a Pharmacodynamic Marker for EWS-FLI1 Activity and Ewing Sarcoma. Sci Rep 2016; 6:33926. [PMID: 27671553 PMCID: PMC5037393 DOI: 10.1038/srep33926] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/31/2016] [Indexed: 12/26/2022] Open
Abstract
Ewing sarcoma is a bone and soft-tissue tumor that depends on the activity of the EWS-FLI1 transcription factor for cell survival. Although a number of compounds have been shown to inhibit EWS-FLI1 in vitro, a clinical EWS-FLI1-directed therapy has not been achieved. One problem plaguing drug development efforts is the lack of a suitable, non-invasive, pharmacodynamic marker of EWS-FLI1 activity. Here we show that 18F-FLT PET (18F- 3′-deoxy-3′-fluorothymidine positron emission tomography) reflects EWS-FLI1 activity in Ewing sarcoma cells both in vitro and in vivo. 18F-FLT is transported into the cell by ENT1 and ENT2, where it is phosphorylated by TK1 and trapped intracellularly. In this report, we show that silencing of EWS-FLI1 with either siRNA or small-molecule EWS-FLI1 inhibitors suppressed the expression of ENT1, ENT2, and TK1 and thus decreased 18F-FLT PET activity. This effect was not through a generalized loss in viability or metabolic suppression, as there was no suppression of 18F-FDG PET activity and no suppression with chemotherapy. These results provide the basis for the clinical translation of 18F-FLT as a companion biomarker of EWS-FLI1 activity and a novel diagnostic imaging approach for Ewing sarcoma.
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Affiliation(s)
- Christy L Osgood
- Division of Pediatric Hematology/Oncology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | | | - Nichole Maloney
- Division of Pediatric Hematology/Oncology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | | | | | | | | | - Jason Buck
- Vanderbilt University Institute of Imaging Science, USA
| | - Mary E Winn
- Van Andel Research Institute, Grand Rapids, MI, USA
| | | | - Patrick J Grohar
- Division of Pediatric Hematology/Oncology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Van Andel Research Institute, Grand Rapids, MI, USA.,Helen De Vos Children's Hospital, Grand Rapids, MI, USA.,Michigan State University School of Medicine, Department of Pediatrics, MI, USA
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14
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Mann A, Han H, Eyal S. Imaging transporters: Transforming diagnostic and therapeutic development. Clin Pharmacol Ther 2016; 100:479-488. [PMID: 27327047 DOI: 10.1002/cpt.416] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 06/13/2016] [Accepted: 06/16/2016] [Indexed: 01/22/2023]
Abstract
Molecular imaging allows noninvasive assessment of drug distribution across pharmacological barriers. Thus, it plays an increasingly important role in efforts to understand the interactions of molecules with membrane transporters during drug development and in clinical pharmacology. We describe established and emerging imaging modalities utilized for studying transporter expression and function. We further present examples of how molecular imaging could provide insights into the contribution of transporters to drug disposition and effects.
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Affiliation(s)
- A Mann
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Israel
| | - H Han
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Israel
| | - S Eyal
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Israel. .,The David R. Bloom Centre for Pharmacy and Dr. Adolf and Klara Brettler Centre for Research in Molecular Pharmacology and Therapeutics at The Hebrew University of Jerusalem, Israel.
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15
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Sengupta D, Pratx G. Single-Cell Characterization of 18F-FLT Uptake with Radioluminescence Microscopy. J Nucl Med 2016; 57:1136-40. [PMID: 27081170 DOI: 10.2967/jnumed.115.167734] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 03/11/2016] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The radiotracer 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) is commonly used to measure cell proliferation in vivo. As a marker of cell proliferation, (18)F-FLT is expected to be differentially taken up by arrested and actively dividing cells, but PET measures only aggregate uptake by tumor cells and therefore the single-cell distribution of (18)F-FLT is unknown. We used a novel in vitro radioluminescence microscopy technique to measure the differential distribution of (18)F-FLT radiotracer with single-cell precision. METHODS Using radioluminescence microscopy, we imaged the absolute uptake of (18)F-FLT in live MDA-MB-231 cells grown under different serum conditions. We then compared (18)F-FLT uptake with a standard measure of cell proliferation, using fluorescence microscopy of 5-ethynyl-2'-deoxyuridine incorporation in fixed cells. RESULTS According to 5-ethynyl-2'-deoxyuridine staining, few cells (1%) actively cycled under serum deprivation whereas most of them (71%) did under 20% serum. The distribution of (18)F-FLT reflected this dynamic. At 0% serum, uptake of (18)F-FLT was heterogeneous but relatively low. At 20% serum, a subpopulation of (18)F-FLT-avid cells, representing 61% of the total population, emerged. Uptake of (18)F-FLT in this population was 5-fold higher than in the remainder of the cells. Such a dichotomous distribution is not typically observed with other radiotracers, such as (18)F-FDG. CONCLUSION These results suggest that increased (18)F-FLT uptake by proliferating cells is due to a greater fraction of (18)F-FLT-avid cells rather than a change in (18)F-FLT uptake by individual cells. This finding is consistent with the fact that (18)F-FLT uptake is mediated by thymidine kinase 1 expression, which is higher in actively dividing cells. Overall, these findings suggest that, within the same patient, changes in (18)F-FLT uptake reflect changes in the number of actively dividing cells, provided other parameters remain the same.
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Affiliation(s)
- Debanti Sengupta
- Department of Radiation Oncology, Stanford University School of Medicine, Palo Alto, California
| | - Guillem Pratx
- Department of Radiation Oncology, Stanford University School of Medicine, Palo Alto, California
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16
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On NH, Yathindranath V, Sun Z, Miller DW. Pathways for Drug Delivery to the Central Nervous System. Drug Deliv 2016. [DOI: 10.1002/9781118833322.ch16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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17
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Alam IS, Arshad MA, Nguyen QD, Aboagye EO. Radiopharmaceuticals as probes to characterize tumour tissue. Eur J Nucl Med Mol Imaging 2015; 42:537-61. [PMID: 25647074 DOI: 10.1007/s00259-014-2984-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 01/06/2023]
Abstract
Tumour cells exhibit several properties that allow them to grow and divide. A number of these properties are detectable by nuclear imaging methods. We discuss crucial tumour properties that can be described by current radioprobe technologies, further discuss areas of emerging radioprobe development, and finally articulate need areas that our field should aspire to develop. The review focuses largely on positron emission tomography and draws upon the seminal 'Hallmarks of Cancer' review article by Hanahan and Weinberg in 2011 placing into context the present and future roles of radiotracer imaging in characterizing tumours.
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Affiliation(s)
- Israt S Alam
- Comprehensive Cancer Imaging Centre, Imperial College London, London, W12 0NN, UK
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18
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Mann A, Semenenko I, Meir M, Eyal S. Molecular Imaging of Membrane Transporters' Activity in Cancer: a Picture is Worth a Thousand Tubes. AAPS JOURNAL 2015; 17:788-801. [PMID: 25823669 DOI: 10.1208/s12248-015-9752-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/09/2015] [Indexed: 01/22/2023]
Abstract
Molecular imaging allows the non-invasive assessment of membrane transporter expression and function in living subjects. Such technologies have the potential to become diagnostic and prognostic tools, allowing detection, localization, and prediction of response of tumors and their metastases to therapy. Beyond tumors, imaging can also help understand the role of transporters in adverse drug effects and drug clearance. Here, we review molecular imaging technologies that monitor transporter-mediated processes. We emphasize emerging probe substrates and potential clinical applications of imaging the function of membrane transporters in cancer.
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Affiliation(s)
- Aniv Mann
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University, Room 613, Ein Kerem, Jerusalem, 91120, Israel
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19
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Damaraju VL, Kuzma M, Mowles D, Cass CE, Sawyer MB. Interactions of Multitargeted Kinase Inhibitors and Nucleoside Drugs: Achilles Heel of Combination Therapy? Mol Cancer Ther 2014; 14:236-45. [DOI: 10.1158/1535-7163.mct-14-0337] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Plotnik DA, Wu S, Linn GR, Yip FCT, Comandante NL, Krohn KA, Toyohara J, Schwartz JL. In vitro analysis of transport and metabolism of 4'-thiothymidine in human tumor cells. Nucl Med Biol 2014; 42:470-474. [PMID: 25659855 PMCID: PMC4387014 DOI: 10.1016/j.nucmedbio.2014.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 11/19/2014] [Accepted: 12/01/2014] [Indexed: 01/11/2023]
Abstract
Introduction The use of thymidine (TdR) and thymidine analogs such as 3′-fluoro-3′-deoxythymidine (FLT) as positron emission tomography (PET)-based proliferation markers can provide information on tumor response to treatment. Studies on another TdR analog, 4'-thiothymidine (4DST), suggest that it might be a better PET-based proliferation tracer than either TdR or FLT. 4DST is resistant to the catabolism that complicates analysis of TdR in PET studies, but unlike FLT, 4DST is incorporated into DNA. Methods To further evaluate 4DST, the kinetics of 4DST transport and metabolism were determined and compared to FLT and TdR. Transport and metabolism of FLT, TdR and 4DST were examined in the human adenocarcinoma cell line A549 under exponential-growth conditions. Single cell suspensions were incubated in buffer supplemented with radiolabeled tracer in the presence or absence of nitrobenzylmercaptopurine ribonucleoside (NBMPR), an inhibitor of equilibrative nucleoside transporters (ENT). Kinetics of tracer uptake was determined in whole cells and tracer metabolism measured by high performance liquid chromatography of cell lysates. Results TdR and 4DST were qualitatively similar in terms of ENT-dependent transport, shapes of uptake curves, and relative levels of DNA incorporation. FLT did not incorporate into DNA, showed a significant temperature effect for uptake, and its transport had a significant NBMPR-resistant component. Overall 4DST metabolism was significantly slower than either TdR or FLT. Conclusions 4DST provides a good alternative for TdR in PET and has advantages over FLT in proliferation measurement. However, slow 4DST metabolism and the short half-life of the 11C label might limit widespread use in PET.
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Affiliation(s)
- David A Plotnik
- Department of Radiation Oncology, University of Washington, Seattle, WA
| | - Stephen Wu
- Department of Radiation Oncology, University of Washington, Seattle, WA
| | - Geoffrey R Linn
- Department of Radiation Oncology, University of Washington, Seattle, WA
| | | | | | - Kenneth A Krohn
- Department of Radiation Oncology, University of Washington, Seattle, WA; Department of Radiology, University of Washington, Seattle, WA
| | - Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Jeffrey L Schwartz
- Department of Radiation Oncology, University of Washington, Seattle, WA.
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21
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Sala R, Nguyen QD, Patel CBK, Mann D, Steinke JHG, Vilar R, Aboagye EO. Phosphorylation status of thymidine kinase 1 following antiproliferative drug treatment mediates 3'-deoxy-3'-[18F]-fluorothymidine cellular retention. PLoS One 2014; 9:e101366. [PMID: 25003822 PMCID: PMC4086825 DOI: 10.1371/journal.pone.0101366] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 06/05/2014] [Indexed: 12/29/2022] Open
Abstract
Background 3′-Deoxy-3′-[18F]-fluorothymidine ([18F]FLT) is being investigated as a Positron Emission Tomography (PET) proliferation biomarker. The mechanism of cellular [18F]FLT retention has been assigned primarily to alteration of the strict transcriptionally regulated S-phase expression of thymidine kinase 1 (TK1). This, however, does not explain how anticancer agents acting primarily through G2/M arrest affect [18F]FLT uptake. We investigated alternative mechanisms of [18F]FLT cellular retention involving post-translational modification of TK1 during mitosis. Methods [18F]FLT cellular retention was assessed in cell lines having different TK1 expression. Drug-induced phosphorylation of TK1 protein was evaluated by MnCl2-phos-tag gel electrophoresis and correlated with [18F]FLT cellular retention. We further elaborated the amino acid residues involved in TK1 phosphorylation by transient transfection of FLAG-pCMV2 plasmids encoding wild type or mutant variants of TK1 into TK1 negative cells. Results Baseline [18F]FLT cellular retention and TK1 protein expression were associated. S-phase and G2/M phase arrest caused greater than two-fold reduction in [18F]FLT cellular retention in colon cancer HCT116 cells (p<0.001). G2/M cell cycle arrest increased TK1 phosphorylation as measured by induction of at least one phosphorylated form of the protein on MnCl2-phos-tag gels. Changes in [18F]FLT cellular retention reflected TK1 phosphorylation and not expression of total protein, in keeping with the impact of phosphorylation on enzyme catalytic activity. Both Ser13 and Ser231 were shown to be involved in the TK1 phosphorylation-modulated [18F]FLT cellular retention; although the data suggested involvement of other amino-acid residues. Conclusion We have defined a regulatory role of TK1 phosphorylation in mediating [18F]FLT cellular retention and hence reporting of antiproliferative activity, with implications especially for drugs that induce a G2/M cell cycle arrest.
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Affiliation(s)
- Roberta Sala
- Comprehensive Cancer Imaging Centre, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Quang-Dé Nguyen
- Comprehensive Cancer Imaging Centre, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Chirag B. K. Patel
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, London, United Kingdom
| | - David Mann
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Joachim H. G. Steinke
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, London, United Kingdom
| | - Ramon Vilar
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, London, United Kingdom
| | - Eric O. Aboagye
- Comprehensive Cancer Imaging Centre, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
- * E-mail:
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Farwell MD, Pryma DA, Mankoff DA. PET/CT imaging in cancer: current applications and future directions. Cancer 2014; 120:3433-45. [PMID: 24947987 DOI: 10.1002/cncr.28860] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/05/2014] [Accepted: 05/05/2014] [Indexed: 12/22/2022]
Abstract
Positron emission tomography (PET) is a radiotracer imaging method that yields quantitative images of regional in vivo biology and biochemistry. PET, now used in conjunction with computed tomography (CT) in PET/CT devices, has had its greatest impact to date on cancer and is now an important part of oncologic clinical practice and translational cancer research. In this review of current applications and future directions for PET/CT in cancer, the authors first highlight the basic principles of PET followed by a discussion of the biochemistry and current clinical applications of the most commonly used PET imaging agent, (18) F-fluorodeoxyglucose (FDG). Then, emerging methods for PET imaging of other biologic processes relevant to cancer are reviewed, including cellular proliferation, tumor hypoxia, apoptosis, amino acid and cell membrane metabolism, and imaging of tumor receptors and other tumor-specific gene products. The focus of the review is on methods in current clinical practice as well as those that have been translated to patients and are currently in clinical trials.
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Affiliation(s)
- Michael D Farwell
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
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23
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Schelhaas S, Wachsmuth L, Viel T, Honess DJ, Heinzmann K, Smith DM, Hermann S, Wagner S, Kuhlmann MT, Müller-Tidow C, Kopka K, Schober O, Schäfers M, Schneider R, Aboagye EO, Griffiths J, Faber C, Jacobs AH. Variability of Proliferation and Diffusion in Different Lung Cancer Models as Measured by 3'-Deoxy-3'-¹⁸F-Fluorothymidine PET and Diffusion-Weighted MR Imaging. J Nucl Med 2014; 55:983-8. [PMID: 24777288 DOI: 10.2967/jnumed.113.133348] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 02/15/2014] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED Molecular imaging allows the noninvasive assessment of cancer progression and response to therapy. The aim of this study was to investigate molecular and cellular determinants of 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) PET and diffusion-weighted (DW) MR imaging in lung carcinoma xenografts. METHODS Four lung cancer cell lines (A549, HTB56, EBC1, and H1975) were subcutaneously implanted in nude mice, and growth was followed by caliper measurements. Glucose uptake and tumor proliferation were determined by (18)F-FDG and (18)F-FLT PET, respectively. T2-weighted MR imaging was performed, and the apparent diffusion coefficient (ADC) was determined by DW MR imaging as an indicator of cell death. Imaging findings were correlated to histology with markers for tumor proliferation (Ki67, 5-bromo-2'-deoxyuridine [BrdU]) and cell death (caspase-3, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling). The expression of human equilibrative nucleoside transporter 1 (hENT1), thymidine kinase 1 (TK1), thymidylate synthase, and thymidine phosphorylase (TP) were analyzed by Western blot and immunohistochemistry. Thymidine levels were determined by liquid chromatography-mass spectrometry. RESULTS Xenografts varied with respect to in vivo growth rates. MR imaging and PET revealed intratumoral heterogeneities, which were confirmed by histology. (18)F-FLT uptake differed significantly between tumor lines, with A549 and H1975 demonstrating the highest radiotracer accumulation (A549, 8.5 ± 3.2; HTB56, 4.4 ± 0.7; EBC1, 4.4 ± 1.2; and H1975, 12.1 ± 3.5 maximal percentage injected dose per milliliter). In contrast, differences in (18)F-FDG uptake were only marginal. No clear relationship between (18)F-FLT accumulation and immunohistochemical markers for tumor proliferation (Ki67, BrdU) as well as hENT1, TK1, or TS expression was detected. However, TP was highly expressed in A549 and H1975 xenografts, which was accompanied by low tumor thymidine concentrations, suggesting that tumor thymidine levels influence (18)F-FLT uptake in the tumor models investigated. MR imaging revealed higher ADC values within proliferative regions of H1975 and A549 tumors than in HTB56 and EBC1. These ADC values were negatively correlated with cell density but not directly related to cell death. CONCLUSION A direct relationship of (18)F-FLT with proliferation or ADC with cell death might be complicated by the interplay of multiple processes at the cellular and physiologic levels in untreated tumors. This issue must be considered when using these imaging modalities in preclinical or clinical settings.
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Affiliation(s)
- Sonja Schelhaas
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | - Lydia Wachsmuth
- Department of Clinical Radiology, University Hospital of Münster, Münster, Germany
| | - Thomas Viel
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | - Davina J Honess
- Cancer Research United Kingdom Cambridge Institute, Cambridge, United Kingdom
| | - Kathrin Heinzmann
- Cancer Research United Kingdom Cambridge Institute, Cambridge, United Kingdom
| | | | - Sven Hermann
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | - Stefan Wagner
- Department of Nuclear Medicine, University Hospital of Münster, Münster, Germany
| | - Michael T Kuhlmann
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany
| | - Carsten Müller-Tidow
- Department of Hematology and Oncology, University Hospital of Münster, Münster, Germany
| | - Klaus Kopka
- Department of Nuclear Medicine, University Hospital of Münster, Münster, Germany
| | - Otmar Schober
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany Department of Nuclear Medicine, University Hospital of Münster, Münster, Germany
| | - Michael Schäfers
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany Department of Nuclear Medicine, University Hospital of Münster, Münster, Germany
| | | | - Eric O Aboagye
- Comprehensive Cancer Imaging Centre, Imperial College London, London, United Kingdom; and
| | - John Griffiths
- Cancer Research United Kingdom Cambridge Institute, Cambridge, United Kingdom
| | - Cornelius Faber
- Department of Clinical Radiology, University Hospital of Münster, Münster, Germany
| | - Andreas H Jacobs
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany Department of Geriatric Medicine, Johanniter Hospital, Bonn, Germany
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Nowosielski M, DiFranco MD, Putzer D, Seiz M, Recheis W, Jacobs AH, Stockhammer G, Hutterer M. An intra-individual comparison of MRI, [18F]-FET and [18F]-FLT PET in patients with high-grade gliomas. PLoS One 2014; 9:e95830. [PMID: 24759867 PMCID: PMC3997484 DOI: 10.1371/journal.pone.0095830] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 03/31/2014] [Indexed: 11/20/2022] Open
Abstract
Objectives Intra-individual spatial overlap analysis of tumor volumes assessed by MRI, the amino acid PET tracer [18F]-FET and the nucleoside PET tracer [18F]-FLT in high-grade gliomas (HGG). Methods MRI, [18F]-FET and [18F]-FLT PET data sets were retrospectively analyzed in 23 HGG patients. Morphologic tumor volumes on MRI (post-contrast T1 (cT1) and T2 images) were calculated using a semi-automatic image segmentation method. Metabolic tumor volumes for [18F]-FET and [18F]-FLT PETs were determined by image segmentation using a threshold-based volume of interest analysis. After co-registration with MRI the morphologic and metabolic tumor volumes were compared on an intra-individual basis in order to estimate spatial overlaps using the Spearman's rank correlation coefficient and the Mann-Whitney U test. Results [18F]-FLT uptake was negative in tumors with no or only moderate contrast enhancement on MRI, detecting only 21 of 23 (91%) HGG. In addition, [18F]-FLT uptake was mainly restricted to cT1 tumor areas on MRI and [18F]-FLT volumes strongly correlated with cT1 volumes (r = 0.841, p<0.001). In contrast, [18F]-FET PET detected 22 of 23 (96%) HGG. [18F]-FET uptake beyond areas of cT1 was found in 61% of cases and [18F]-FET volumes showed only a moderate correlation with cT1 volumes (r = 0.573, p<0.001). Metabolic tumor volumes beyond cT1 tumor areas were significantly larger for [18F]-FET compared to [18F]-FLT tracer uptake (8.3 vs. 2.7 cm3, p<0.001). Conclusion In HGG [18F]-FET but not [18F]-FLT PET was able to detect metabolic active tumor tissue beyond contrast enhancing tumor on MRI. In contrast to [18F]-FET, blood-brain barrier breakdown seems to be a prerequisite for [18F]-FLT tracer uptake.
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Affiliation(s)
- Martha Nowosielski
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
- * E-mail:
| | - Matthew D. DiFranco
- Department of Oto-, Rhino- and Laryngology with 4D Visualization Lab, Innsbruck Medical University, Innsbruck, Austria
- Department of Radiology, Computational Image Analysis and Radiology Lab (CIR), Medical University of Vienna, Vienna, Austria
| | - Daniel Putzer
- Department of Nuclear Medicine, Innsbruck Medical University, Innsbruck, Austria
| | - Marcel Seiz
- Department of Neurosurgery, Innsbruck Medical University, Innsbruck, Austria
- Department of Neurosurgery, Mannheim Medical University, Mannheim, Germany
| | - Wolfgang Recheis
- Department of Radiology, Innsbruck Medical University, Innsbruck, Austria
| | - Andreas H. Jacobs
- European Institute for Molecular Imaging (EIMI) at the Westphalian Wilhelms University, Münster, Germany
- Department of Geriatrics at Evangelische Kliniken, Johanniter Krankenhaus, Bonn, Germany
| | | | - Markus Hutterer
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
- Department of Neurology and Wilhelm-Sander Neurooncology Unity, University Hospital and Medical School Regensburg, Regensburg, Germany
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Liu D, Chalkidou A, Landau DB, Marsden PK, Fenwick JD. 18F-FLT uptake kinetics in head and neck squamous cell carcinoma: a PET imaging study. Med Phys 2014; 41:041911. [PMID: 24694142 DOI: 10.1118/1.4868462] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 02/05/2014] [Accepted: 02/28/2014] [Indexed: 02/11/2024] Open
Abstract
PURPOSE To analyze the kinetics of 3(')-deoxy-3(')-[F-18]-fluorothymidine (18F-FLT) uptake by head and neck squamous cell carcinomas and involved nodes imaged using positron emission tomography (PET). METHODS Two- and three-tissue compartment models were fitted to 12 tumor time-activity-curves (TACs) obtained for 6 structures (tumors or involved nodes) imaged in ten dynamic PET studies of 1 h duration, carried out for five patients. The ability of the models to describe the data was assessed using a runs test, the Akaike information criterion (AIC) and leave-one-out cross-validation. To generate parametric maps the models were also fitted to TACs of individual voxels. Correlations between maps of different parameters were characterized using Pearson'sr coefficient; in particular the phosphorylation rate-constants k3-2tiss and k5 of the two- and three-tissue models were studied alongside the flux parameters KFLT- 2tiss and KFLT of these models, and standardized uptake values (SUV). A methodology based on expectation-maximization clustering and the Bayesian information criterion ("EM-BIC clustering") was used to distil the information from noisy parametric images. RESULTS Fits of two-tissue models 2C3K and 2C4K and three-tissue models 3C5K and 3C6K comprising three, four, five, and six rate-constants, respectively, pass the runs test for 4, 8, 10, and 11 of 12 tumor TACs. The three-tissue models have lower AIC and cross-validation scores for nine of the 12 tumors. Overall the 3C6K model has the lowest AIC and cross-validation scores and its fitted parameter values are of the same orders of magnitude as literature estimates. Maps of KFLT and KFLT- 2tiss are strongly correlated (r = 0.85) and also correlate closely with SUV maps (r = 0.72 for KFLT- 2tiss, 0.64 for KFLT). Phosphorylation rate-constant maps are moderately correlated with flux maps (r = 0.48 for k3-2tiss vs KFLT- 2tiss and r = 0.68 for k5 vs KFLT); however, neither phosphorylation rate-constant correlates significantly with SUV. EM-BIC clustering reduces the parametric maps to a small number of levels--on average 5.8, 3.5, 3.4, and 1.4 for KFLT- 2tiss, KFLT, k3-2tiss, and k5. This large simplification is potentially useful for radiotherapy dose-painting, but demonstrates the high noise in some maps. Statistical simulations show that voxel level noise degrades TACs generated from the 3C6K model sufficiently that the average AIC score, parameter bias, and total uncertainty of 2C4K model fits are similar to those of 3C6K fits, whereas at the whole tumor level the scores are lower for 3C6K fits. CONCLUSIONS For the patients studied here, whole tumor FLT uptake time-courses are represented better overall by a three-tissue than by a two-tissue model. EM-BIC clustering simplifies noisy parametric maps, providing the best description of the underlying information they contain and is potentially useful for radiotherapy dose-painting. However, the clustering highlights the large degree of noise present in maps of the phosphorylation rate-constantsk5 and k3-2tiss, which are conceptually tightly linked to cellular proliferation. Methods must be found to make these maps more robust-either by constraining other model parameters or modifying dynamic imaging protocols.
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Affiliation(s)
- Dan Liu
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
| | - Anastasia Chalkidou
- Division of Imaging Sciences and Biomedical Engineering, School of Medicine, King's College London, St Thomas Hospital, Westminster Bridge Road, London SE1 7EH, United Kingdom
| | - David B Landau
- Division of Imaging Sciences and Biomedical Engineering, School of Medicine, King's College London, St Thomas Hospital, Westminster Bridge Road, London SE1 7EH, United Kingdom
| | - Paul K Marsden
- Division of Imaging Sciences and Biomedical Engineering, School of Medicine, King's College London, St Thomas Hospital, Westminster Bridge Road, London SE1 7EH, United Kingdom
| | - John D Fenwick
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
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Thymidine phosphorylase influences [18F]fluorothymidine uptake in cancer cells and patients with non-small cell lung cancer. Eur J Nucl Med Mol Imaging 2014; 41:1327-35. [DOI: 10.1007/s00259-014-2712-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 01/20/2014] [Indexed: 01/09/2023]
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27
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Haagensen EJ, Thomas HD, Wilson I, Harnor SJ, Payne SL, Rennison T, Smith KM, Maxwell RJ, Newell DR. The enhanced in vivo activity of the combination of a MEK and a PI3K inhibitor correlates with [18F]-FLT PET in human colorectal cancer xenograft tumour-bearing mice. PLoS One 2013; 8:e81763. [PMID: 24339963 PMCID: PMC3858267 DOI: 10.1371/journal.pone.0081763] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/16/2013] [Indexed: 12/17/2022] Open
Abstract
Combined targeting of the MAPK and PI3K signalling pathways in cancer may be necessary for optimal therapeutic activity. To support clinical studies of combination therapy, 3′-deoxy-3′-[18F]-fluorothymidine ([18F]-FLT) uptake measured by Positron Emission Tomography (PET) was evaluated as a non-invasive surrogate response biomarker in pre-clinical models. The in vivo anti-tumour efficacy and PK-PD properties of the MEK inhibitor PD 0325901 and the PI3K inhibitor GDC-0941, alone and in combination, were evaluated in HCT116 and HT29 human colorectal cancer xenograft tumour-bearing mice, and [18F]-FLT PET investigated in mice bearing HCT116 xenografts. Dual targeting of PI3K and MEK induced marked tumour growth inhibition in vivo, and enhanced anti-tumour activity was predicted by [18F]-FLT PET scanning after 2 days of treatment. Pharmacodynamic analyses using the combination of the PI3K inhibitor GDC-0941 and the MEK inhibitor PD 0325901 revealed that increased efficacy is associated with an enhanced inhibition of the phosphorylation of ERK1/2, S6 and 4EBP1, compared to that observed with either single agent, and maintained inhibition of AKT phosphorylation. Pharmacokinetic studies indicated that there was no marked PK interaction between the two drugs. Together these results indicate that the combination of PI3K and MEK inhibitors can result in significant efficacy, and demonstrate for the first time that [18F]-FLT PET can be correlated to the improved efficacy of combined PI3K and MEK inhibitor treatment.
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Affiliation(s)
- Emma J. Haagensen
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, United Kingdom
| | - Huw D. Thomas
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, United Kingdom
| | - Ian Wilson
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, United Kingdom
| | - Suzannah J. Harnor
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Bedson Building, Newcastle University, Newcastle, United Kingdom
| | - Sara L. Payne
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Bedson Building, Newcastle University, Newcastle, United Kingdom
| | - Tommy Rennison
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Bedson Building, Newcastle University, Newcastle, United Kingdom
| | - Kate M. Smith
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Bedson Building, Newcastle University, Newcastle, United Kingdom
| | - Ross J. Maxwell
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, United Kingdom
| | - David R. Newell
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, United Kingdom
- * E-mail:
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Young JD, Yao SYM, Baldwin JM, Cass CE, Baldwin SA. The human concentrative and equilibrative nucleoside transporter families, SLC28 and SLC29. Mol Aspects Med 2013; 34:529-47. [PMID: 23506887 DOI: 10.1016/j.mam.2012.05.007] [Citation(s) in RCA: 243] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/11/2012] [Indexed: 12/23/2022]
Abstract
Nucleoside transport in humans is mediated by members of two unrelated protein families, the SLC28 family of cation-linked concentrative nucleoside transporters (CNTs) and the SLC29 family of energy-independent, equilibrative nucleoside transporters (ENTs). These families contain three and four members, respectively, which differ both in the stoichiometry of cation coupling and in permeant selectivity. Together, they play key roles in nucleoside and nucleobase uptake for salvage pathways of nucleotide synthesis. Moreover, they facilitate cellular uptake of several nucleoside and nucleobase drugs used in cancer chemotherapy and treatment of viral infections. Thus, the transporter content of target cells can represent a key determinant of the response to treatment. In addition, by regulating the concentration of adenosine available to cell surface receptors, nucleoside transporters modulate many physiological processes ranging from neurotransmission to cardiovascular activity. This review describes the molecular and functional properties of the two transporter families, with a particular focus on their physiological roles in humans and relevance to disease treatment.
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Affiliation(s)
- James D Young
- Membrane Protein Research Group, Edmonton, Alberta, Canada T6G 2H7.
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29
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Hung SW, Mody H, Marrache S, Bhutia YD, Davis F, Cho JH, Zastre J, Dhar S, Chu CK, Govindarajan R. Pharmacological reversal of histone methylation presensitizes pancreatic cancer cells to nucleoside drugs: in vitro optimization and novel nanoparticle delivery studies. PLoS One 2013; 8:e71196. [PMID: 23940717 PMCID: PMC3735519 DOI: 10.1371/journal.pone.0071196] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 06/27/2013] [Indexed: 01/29/2023] Open
Abstract
We evaluated the potential of an investigational histone methylation reversal agent, 3-deazaneplanocin A (DZNep), in improving the chemosensitivity of pancreatic cancer to nucleoside analogs (i.e., gemcitabine). DZNep brought delayed but selective cytotoxicity to pancreatic cancer cells without affecting normal human pancreatic ductal epithelial (HPDE) cells. Co-exposure of DZNep and gemcitabine induced cytotoxic additivity or synergism in both well- and poorly-differentiated pancreatic cell lines by increased apoptosis. In contrast, DZNep exerted antagonism with gemcitabine against HPDE cells with significant reduction in cytotoxicity compared with the gemcitabine-alone regimen. DZNep marginally depended on purine nucleoside transporters for its cytotoxicity, but the transport dependence was circumvented by acyl derivatization. Drug exposure studies revealed that a short priming with DZNep followed by gemcitabine treatment rather than co-treatment of both agents to produce a maximal chemosensitization response in both gemcitabine-sensitive and gemcitabine-resistant pancreatic cancer cells. DZNep rapidly and reversibly decreased trimethylation of histone H3 lysine 27 but increased trimethylation of lysine 9 in an EZH2- and JMJD1A/2C-dependent manner, respectively. However, DZNep potentiation of nucleoside analog chemosensitization was found to be temporally coupled to trimethylation changes in lysine 27 and not lysine 9. Polymeric nanoparticles engineered to chronologically release DZNep followed by gemcitabine produced pronounced chemosensitization and dose-lowering effects. Together, our results identify that an optimized DZNep exposure can presensitize pancreatic cancer cells to anticancer nucleoside analogs through the reversal of histone methylation, emphasizing the promising clinical utilities of epigenetic reversal agents in future pancreatic cancer combination therapies.
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Affiliation(s)
- Sau Wai Hung
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, Georgia, United States of America
| | - Hardik Mody
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, Georgia, United States of America
| | - Sean Marrache
- Department of Chemistry, The University of Georgia, Athens, Georgia, United States of America
| | - Yangzom D. Bhutia
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, Georgia, United States of America
| | - Franklin Davis
- Department of Biological Sciences, The University of Georgia, Athens, Georgia, United States of America
| | - Jong Hyun Cho
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, Georgia, United States of America
| | - Jason Zastre
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, Georgia, United States of America
| | - Shanta Dhar
- Department of Chemistry, The University of Georgia, Athens, Georgia, United States of America
| | - Chung K. Chu
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, Georgia, United States of America
| | - Rajgopal Govindarajan
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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30
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Kudgus RA, Szabolcs A, Khan JA, Walden CA, Reid JM, Robertson JD, Bhattacharya R, Mukherjee P. Inhibiting the growth of pancreatic adenocarcinoma in vitro and in vivo through targeted treatment with designer gold nanotherapeutics. PLoS One 2013; 8:e57522. [PMID: 23483913 PMCID: PMC3590245 DOI: 10.1371/journal.pone.0057522] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 01/22/2013] [Indexed: 01/05/2023] Open
Abstract
Background Pancreatic cancer is one of the deadliest of all human malignancies with limited options for therapy. Here, we report the development of an optimized targeted drug delivery system to inhibit advanced stage pancreatic tumor growth in an orthotopic mouse model. Method/Principal Findings Targeting specificity in vitro was confirmed by preincubation of the pancreatic cancer cells with C225 as well as Nitrobenzylthioinosine (NBMPR - nucleoside transporter (NT) inhibitor). Upon nanoconjugation functional activity of gemcitabine was retained as tested using a thymidine incorporation assay. Significant stability of the nanoconjugates was maintained, with only 12% release of gemcitabine over a 24-hour period in mouse plasma. Finally, an in vivo study demonstrated the inhibition of tumor growth through targeted delivery of a low dose of gemcitabine in an orthotopic model of pancreatic cancer, mimicking an advanced stage of the disease. Conclusion We demonstrated in this study that the gold nanoparticle-based therapeutic containing gemcitabine inhibited tumor growth in an advanced stage of the disease in an orthotopic model of pancreatic cancer. Future work would focus on understanding the pharmacokinetics and combining active targeting with passive targeting to further improve the therapeutic efficacy and increase survival.
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Affiliation(s)
- Rachel A. Kudgus
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Annamaria Szabolcs
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Jameel Ahmad Khan
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Chad A. Walden
- Department of Physiology and Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Joel M. Reid
- Department of Physiology and Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - J. David Robertson
- Department of Chemistry and University of Missouri Research Reactor, University of Missouri, Columbia, Missouri, United States of America
| | - Resham Bhattacharya
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Priyabrata Mukherjee
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Physiology and Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Mayo Clinic Cancer Center, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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Shinomiya A, Miyake K, Okada M, Nakamura T, Kawai N, Kushida Y, Haba R, Kudomi N, Tokuda M, Tamiya T. 3'-Deoxy-3'-[(18)F]-fluorothymidine ([(18)F]-FLT) transport in newly diagnosed glioma: correlation with nucleoside transporter expression, vascularization, and blood-brain barrier permeability. Brain Tumor Pathol 2013; 30:215-23. [PMID: 23423309 DOI: 10.1007/s10014-013-0136-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 01/31/2013] [Indexed: 10/27/2022]
Abstract
3'-Deoxy-3'-[(18)F]-fluorothymidine ([(18)F]-FLT), a marker of cellular proliferation, has been used in positron emission tomography (PET) examination of gliomas. The aim of this study was to investigate whether the uptake of [(18)F]-FLT in glioma correlates with messenger RNA (mRNA) levels of the equilibrative nucleoside transporter 1 (ENT1), microvascular density (assessed by CD34 immunohistochemistry), and the blood-brain barrier (BBB) breakdown. A total of 21 patients with newly diagnosed glioma were examined with [(18)F]-FLT PET. Tumor lesions were identified as areas of focally increased [(18)F]-FLT uptake, exceeding that of surrounding normal tissue. Dynamic analysis of [(18)F]-FLT PET revealed correlations between the phosphorylation rate constant k 3 and ENT1 expression; however there was no correlation between the kinetic parameters and CD34 score. There was a good correlation between the gadolinium (Gd) enhancement score (evaluating BBB breakdown) and ENT1 expression, CD34 score, and Ki-67 index. This preliminary study suggests that ENT1 expression might not reflect accumulation of [(18)F]-FLT in vivo due to BBB permeability in glioma.
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Affiliation(s)
- Aya Shinomiya
- Department of Neurological Surgery, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki, Kagawa, 761-0173, Japan,
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Paproski RJ, Yao SYM, Favis N, Evans D, Young JD, Cass CE, Zemp RJ. Human concentrative nucleoside transporter 3 transfection with ultrasound and microbubbles in nucleoside transport deficient HEK293 cells greatly increases gemcitabine uptake. PLoS One 2013; 8:e56423. [PMID: 23441192 PMCID: PMC3575408 DOI: 10.1371/journal.pone.0056423] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 01/09/2013] [Indexed: 02/06/2023] Open
Abstract
Gemcitabine is a hydrophilic clinical anticancer drug that requires nucleoside transporters to cross plasma membranes and enter cells. Pancreatic adenocarcinomas with low levels of nucleoside transporters are generally resistant to gemcitabine and are currently a clinical problem. We tested whether transfection of human concentrative nucleoside transporter 3 (hCNT3) using ultrasound and lipid stabilized microbubbles could increase gemcitabine uptake and sensitivity in HEK293 cells made nucleoside transport deficient by pharmacologic treatment with dilazep. To our knowledge, no published data exists regarding the utility of using hCNT3 as a therapeutic gene to reverse gemcitabine resistance. Our ultrasound transfection system - capable of transfection of cell cultures, mouse muscle and xenograft CEM/araC tumors - increased hCNT3 mRNA and 3H-gemcitabine uptake by >2,000– and 3,400–fold, respectively, in dilazep-treated HEK293 cells. Interestingly, HEK293 cells with both functional human equilibrative nucleoside transporters and hCNT3 displayed 5% of 3H-gemcitabine uptake observed in cells with only functional hCNT3, suggesting that equilibrative nucleoside transporters caused significant efflux of 3H-gemcitabine. Efflux assays confirmed that dilazep could inhibit the majority of 3H-gemcitabine efflux from HEK293 cells, suggesting that hENTs were responsible for the majority of efflux from the tested cells. Oocyte uptake transport assays were also performed and provided support for our hypothesis. Gemcitabine uptake and efflux assays were also performed on pancreatic cancer AsPC-1 and MIA PaCa-2 cells with similar results to that of HEK293 cells. Using the MTS proliferation assay, dilazep-treated HEK293 cells demonstrated 13-fold greater resistance to gemcitabine compared to dilazep-untreated HEK293 cells and this resistance could be reversed by transfection of hCNT3 cDNA. We propose that transfection of hCNT3 cDNA using ultrasound and microbubbles may be a method to reverse gemcitabine resistance in pancreatic tumors that have little nucleoside transport activity which are resistant to almost all current anticancer therapies.
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Affiliation(s)
- Robert J. Paproski
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Sylvia Y. M. Yao
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Nicole Favis
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - David Evans
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - James D. Young
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Carol E. Cass
- Department of Oncology, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Roger J. Zemp
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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LEE EUNJUNG, LEE SEUNGJIN. Etoposide increases equilibrative nucleoside transporter 1 activity and fluorothymidine uptake: Screening of 60 cytotoxic agents. Oncol Rep 2012; 29:763-70. [DOI: 10.3892/or.2012.2172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/17/2012] [Indexed: 11/06/2022] Open
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Tsao N, Chanda M, Yu DF, Kurihara H, Zhang YH, Mendez R, Yang DJ. ⁹⁹mTc-N4amG: synthesis biodistribution and imaging in breast tumor-bearing rodents. Appl Radiat Isot 2012. [PMID: 23208240 DOI: 10.1016/j.apradiso.2012.07.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
(99m)Tc-N4-guanine ((99m)Tc-N4amG) was synthesized and evaluated in this study. Cellular uptake and cellular fraction studies were performed to evaluate the cell penetrating ability. Biodistribution and planar imaging were conducted in breast tumor-bearing rats. Up to 17%ID uptake was observed in cellular uptake study with 40% of (99m)Tc-N4amG was accumulated in the nucleus. Biodistribution and scintigraphic imaging studies showed increased tumor/muscle count density ratios as a function of time. Our results demonstrate the feasibility of using (99m)Tc-N4amG in tumor specific imaging.
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Affiliation(s)
- Ning Tsao
- Division of Diagnostic Imaging, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
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Fuchs K, Kohlhofer U, Quintanilla-Martinez L, Lamparter D, Kötter I, Reischl G, Röcken M, Pichler BJ, Kneilling M. In vivo imaging of cell proliferation enables the detection of the extent of experimental rheumatoid arthritis by 3'-deoxy-3'-18f-fluorothymidine and small-animal PET. J Nucl Med 2012; 54:151-8. [PMID: 23213198 DOI: 10.2967/jnumed.112.106740] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
UNLABELLED The aim of this work was to study the feasibility of measuring cell proliferation noninvasively in vivo during different stages of experimental arthritis using the PET proliferation tracer 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT). METHODS We injected mice with serum containing glucose-6-phosphate-isomerase-specific antibodies to induce experimental arthritis, and we injected control mice with control serum. Animals injected with (18)F-FLT 1, 3, 6, and 8 d after the onset of disease were analyzed in vivo by PET, PET/CT, or PET/MR imaging followed by autoradiography analysis. The (18)F-FLT uptake in the ankles and forepaws was quantified on the basis of the PET images by drawing standardized regions of interest. To correlate the in vivo PET data with cell proliferation, we performed Ki-67 immunohistochemistry of diseased and healthy joints at the corresponding time points. RESULTS Analysis of the different stages of arthritic joint disease revealed enhanced (18)F-FLT uptake in arthritic ankles (2.2 ± 0.2 percentage injected dose per gram [%ID/g]) and forepaws (2.1 ± 0.3 %ID/g), compared with healthy ankles (1.4 ± 0.3 %ID/g) and forepaws (1.5 ± 0.5 %ID/g), as early as 1 d after the glucose-6-phosphate-isomerase serum injection, a time point characterized by clear histologic signs of arthritis but only slight ankle swelling. The (18)F-FLT uptake in the ankles (3.5 ± 0.3 %ID/g) reached the maximum observed level at day 8. Ki-67 immunohistochemical staining of the arthritic ankles and forepaws revealed a strong correlation with the in vivo (18)F-FLT PET data. PET/CT and PET/MR imaging measurements enabled us to identify whether the (18)F-FLT uptake was located in the bone or the soft tissue. CONCLUSION Noninvasive in vivo measurement of cell proliferation in experimental arthritis using (18)F-FLT PET is a promising tool to investigate the extent of arthritic joint inflammation.
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Affiliation(s)
- Kerstin Fuchs
- Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens-Foundation, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany
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Moysan E, Bastiat G, Benoit JP. Gemcitabine versus Modified Gemcitabine: a review of several promising chemical modifications. Mol Pharm 2012; 10:430-44. [PMID: 22978251 DOI: 10.1021/mp300370t] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Gemcitabine, an anticancer agent which acts against a wide range of solid tumors, is known to be rapidly deaminated in blood to the inactive metabolite 2',2'-difluorodeoxyuridine and to be rapidly excreted by the urine. Moreover, many cancers develop resistance against this drug, such as loss of transporters and kinases responsible for the first phosphorylation step. To increase its therapeutic levels, gemcitabine is administered at high doses (1000 mg/m(2)) causing side effects (neutropenia, nausea, and so forth). To improve its metabolic stability and cytotoxic activity and to limit the phenomena of resistance many alternatives have emerged, such as the synthesis of prodrugs. Modifying an anticancer agent is not new; paclitaxel or ara-C has been subjected to such changes. This review summarizes the various chemical modifications that can be found in the 4-(N)- and 5'-positions of gemcitabine. They can provide (i) a protection against deamination, (ii) a better storage and (iii) a prolonged release in the cell, (iv) a possible use in the case of deoxycytidine kinase deficiency, and (v) transporter deficiency. These new gemcitabine-based sysems have the potential to improve the clinical outcome of a chemotherapy strategy.
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Affiliation(s)
- Elodie Moysan
- LUNAM Université -Micro et Nanomédecines Biomimétiques, F-49933 Angers, France
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Plotnik DA, Asher C, Chu SK, Miyaoka RS, Garwin GG, Johnson BW, Li T, Krohn KA, Schwartz JL. Levels of human equilibrative nucleoside transporter-1 are higher in proliferating regions of A549 tumor cells grown as tumor xenografts in vivo. Nucl Med Biol 2012; 39:1161-6. [PMID: 22985987 DOI: 10.1016/j.nucmedbio.2012.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 07/26/2012] [Indexed: 11/18/2022]
Abstract
UNLABELLED 3'-Fluoro-3'-deoxythymidine (FLT) has been proposed for positron emission tomography (PET)-based identification of tumor chemosensitivity that is mediated by the human equilibrative nucleoside transporter-1 (ENT1). ENT1 facilitates transport of FLT into cells and elevated levels of FLT are associated with both larger FLT-PET signals and increased response to nucleoside-based chemotherapies. FLT-PET is also used as a measure of tumor proliferation. The present study examined the extent to which ENT1 levels vary in a proliferation-dependent manner in tumor cells in vivo. METHODS The human adenocarcinoma cell line A549 was used to establish tumor xenografts in nude mice. FLT uptake was measured in vivo using PET, and further examined ex vivo using autoradiography. FLT uptake patterns were compared to immunohistochemical (IHC) analysis of ENT1 and the proliferation markers Ki67 and BrdU. RESULTS Regional differences in FLT uptake matched differences in IHC proliferation markers. All cells stained for ENT1, but the staining intensity was twice as high for Ki67(+) cells than for Ki67(-) cells. CONCLUSIONS Under in vivo conditions, proliferating regions of tumors show increased FLT uptake and higher ENT1 levels than nonproliferating tumor regions.
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Affiliation(s)
- David A Plotnik
- Department of Radiation Oncology, Box 356069, University of Washington, Seattle, WA 98195 USA
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Park JS, Hammond JR. Cysteine Residues in the Transmembrane (TM) 9 to TM11 Region of the Human Equilibrative Nucleoside Transporter Subtype 1 Play an Important Role in Inhibitor Binding and Translocation Function. Mol Pharmacol 2012; 82:784-94. [DOI: 10.1124/mol.112.079616] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Viertl D, Perillo-Adamer F, André PA, Ametamey SM, Ross TL, Kosinski M, Dupertuis YM, Bischof Delaloye A, Buchegger F. 18F-FLT and 125I-IdUrd uptake increase in human tumour cell lines induced by the thymidylate synthase inhibitor FdUrd. Nuklearmedizin 2012; 51:163-9. [PMID: 22576273 DOI: 10.3413/nukmed-0459-12-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 04/30/2012] [Indexed: 11/20/2022]
Abstract
AIM 5-fluoro-2'-deoxyuridine (FdUrd) depletes the endogenous 5'-deoxythymidine triphosphate (dTTP) pool. We hypothesized whether uptake of exogenous dThd analogues could be favoured through a feedback enhanced salvage pathway and studied the FdUrd effect on cellular uptake of 3'-deoxy-3'-18F-fluorothymidine (18F-FLT) and 5-125I-iodo-2'-deoxyuridine (125I-IdUrd) in different cancer cell lines in parallel. METHODS Cell uptake of 18F-FLT and 125I-IdUrd was studied in 2 human breast, 2 colon cancer and 2 glioblastoma lines. Cells were incubated with/without 1 µmol/l FdUrd for 1 h and, after washing, with 1.2 MBq 18F-FLT or 125I-IdUrd for 0.3 to 2 h. Cell bound 18F-FLT and 125I-IdUrd was counted and expressed in % incubated activity (%IA). Kinetics of 18F-FLT cell uptake and release were studied with/without FdUrd modulation. 2'-3H-methyl-fluorothymidine (2'-3H-FLT) uptake with/without FdUrd pretreatment was tested on U87 spheroids and monolayer cells. RESULTS Basal uptake at 2 h of 18F-FLT and 125I-IdUrd was in the range of 0.8-1.0 and 0.4-0.6 Bq/cell, respectively. FdUrd pretreatment enhanced 18F-FLT and 125I-IdUrd uptake 1.2-2.1 and 1.7-4.4 fold, respectively, while co-incubation with excess thymidine abrogated all 18F-FLT uptake. FdUrd enhanced 18F-FLT cellular inflow in 2 breast cancer lines by factors of 1.8 and 1.6, respectively, while outflow persisted at a slightly lower rate. 2'-3H-FLT basal uptake was very low while uptake increase after FdUrd was similar in U87 monolayer cells and spheroids. CONCLUSIONS Basal uptake of 18F-FLT was frequently higher than that of 125I-IdUrd but FdUrd induced uptake enhancement was stronger for 125I-IdUrd in five of six cell lines. 18F-FLT outflow from cells might be an explanation for the observed difference with 125I-IdUrd.
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Affiliation(s)
- D Viertl
- Department of Nuclear Medicine, University Hospital of Lausanne, Switzerland.
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Plotnik DA, McLaughlin LJ, Krohn KA, Schwartz JL. The effects of 5-fluoruracil treatment on 3'-fluoro-3'-deoxythymidine (FLT) transport and metabolism in proliferating and non-proliferating cultures of human tumor cells. Nucl Med Biol 2012; 39:970-6. [PMID: 22560972 DOI: 10.1016/j.nucmedbio.2012.03.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 02/21/2012] [Accepted: 03/20/2012] [Indexed: 01/19/2023]
Abstract
UNLABELLED 3'-Fluoro-3'-deoxythymidine (FLT) positron emission tomography (PET) has been proposed for imaging thymidylate synthase (TS) inhibition. Agents that target TS and shut down de novo synthesis of thymidine monophosphate increase the uptake and retention of FLT in vitro and in vivo because of a compensating increase in the salvage pathway. Increases in both thymidine kinase-1 (TK1) and the equilibrative nucleoside transporter hENT1 have been reported to underlie this effect. We examined whether the effects of one TS inhibitor, 5-fluorouracil (5FU), on FLT uptake require proliferating cells and whether the effects are limited to increasing TK1 activity. METHODS The effects of 5FU on FLT transport and metabolism, TK1 activity, and cell cycle progression were evaluated in the human tumor cell line, A549, maintained as either a proliferating or non-proliferating culture. RESULTS There were dose-dependent increases in FLT uptake that peaked after a 10 μM 5FU exposure and then declined to baseline levels or below at higher doses in both proliferating and non-proliferating cultures. The dose-dependence for FLT uptake was mirrored by changes in TK1 activity. S phase fraction did not correlate with FLT uptake in proliferating cultures. Chemical inhibition of hENT1 reduced overall levels of FLT uptake but did not affect the low dose increase in FLT uptake. CONCLUSIONS 5FU only affects FLT uptake in proliferating A549 cells and increases in FLT uptake are directly related to increased TK1 activity. Our studies did not support a role for hENT1 in the increased uptake of FLT after exposure to 5FU. Our studies with A549 cells support the suggestion that FLT-PET could provide a measure of TS inhibition in vivo.
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Affiliation(s)
- David A Plotnik
- Department of Radiation Oncology, University of Washington, Box 356069 Seattle, WA 98195, USA
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Fuchs K, Kukuk D, Reischl G, Föller M, Eichner M, Reutershan J, Lang F, Röcken M, Pichler BJ, Kneilling M. Oxygen Breathing Affects 3′-Deoxy-3′-18F-Fluorothymidine Uptake in Mouse Models of Arthritis and Cancer. J Nucl Med 2012; 53:823-30. [DOI: 10.2967/jnumed.111.101808] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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Soloviev D, Lewis D, Honess D, Aboagye E. [(18)F]FLT: an imaging biomarker of tumour proliferation for assessment of tumour response to treatment. Eur J Cancer 2012; 48:416-24. [PMID: 22209266 DOI: 10.1016/j.ejca.2011.11.035] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 11/27/2011] [Indexed: 01/13/2023]
Abstract
The paradigm of drug development is shifting towards early use of imaging biomarkers as surrogate end-points in clinical trials. Quantitative Imaging in Cancer: Connecting Cellular Processes (QuIC-ConCePT) is an initiative to qualify complementary imaging biomarkers (IB) of proliferation, cell death and tumour heterogeneity as possible tools in early phase clinical trials to help pharmaceutical developers in 'go, no-go' decisions early in the process of drug development. One of the IBs is [(18)F]3'-deoxy-3'-fluorothymidine with Positron Emission Tomography (FLT-PET). We review results of recent clinical trials using FLT-PET for monitoring tumour response to drug treatment and discuss the potential and the possible pitfalls of using this IB as a surrogate end-point in early phase clinical trials for assessing tumour response to drug treatment. From first human trial results it seems that the degree of FLT accumulation in tumours is governed not only by the tumour proliferation rate but also by other factors. Nevertheless FLT-PET could potentially be used as a negative predictor of tumour response to chemotherapy, and hence evaluation of this IB is granted in multi-centre clinical trials.
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Affiliation(s)
- Dmitry Soloviev
- Cancer Research UK, Cambridge Research Institute, Cambridge CB2 0RE, UK.
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Zhang CC, Yan Z, Li W, Kuszpit K, Painter CL, Zhang Q, Lappin PB, Nichols T, Lira ME, Affolter T, Fahey NR, Cullinane C, Spilker M, Zasadny K, O'Brien P, Buckman D, Wong A, Christensen JG. [(18)F]FLT-PET imaging does not always "light up" proliferating tumor cells. Clin Cancer Res 2011; 18:1303-12. [PMID: 22170262 DOI: 10.1158/1078-0432.ccr-11-1433] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE [(18)F]FLT (3'-Fluoro-3' deoxythymidine)-PET imaging was proposed as a tool for measuring in vivo tumor cell proliferation. The aim of this article was to validate the use of [(18)F]FLT-PET imaging for measuring xenograft proliferation and subsequent monitoring of targeted therapy. EXPERIMENTAL DESIGN In exponentially growing xenografts, factors that could impact the outcome of [(18)F]FLT-PET imaging, such as nucleoside transporters, thymidine kinase 1, the relative contribution of DNA salvage pathway, and the ratio of FLT to thymidine, were evaluated. The [(18)F]FLT tracer avidity was compared with other proliferation markers. RESULTS In a panel of proliferating xenografts, [(18)F]FLT or [(3)H]thymidine tracer avidity failed to reflect the tumor growth rate across different tumor types, despite the high expressions of Ki67 and TK1. When FLT was injected at the same dose level as used in the preclinical [(18)F]FLT-PET imaging, the plasma exposure ratio of FLT to thymidine was approximately 1:200. Thymidine levels in different tumor types seemed to be variable and exhibited an inverse relationship with the FLT tracer avidity. In contrast, high-dose administration of bromdeoxyuridine (BrdUrd; 50 mg/kg) yielded a plasma exposure of more than 4-fold higher than thymidine and leads to a strong correlation between the BrdUrd uptake and the tumor proliferation rate. In FLT tracer-avid models, [(18)F]FLT-PET imaging as a surrogate biomarker predicted the therapeutic response of CDK4/6 inhibitor PD-0332991. CONCLUSIONS Tumor thymidine level is one of the factors that impact the correlation between [(18)F]FLT uptake and tumor cell proliferation. With careful validation, [(18)F]FLT-PET imaging can be used to monitor antiproliferative therapies in tracer-avid malignancies.
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Affiliation(s)
- Cathy C Zhang
- Oncology Research Unit, La Jolla Laboratories, Pfizer Global Research and Development, San Diego, California 92121, USA.
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Wardak M, Schiepers C, Dahlbom M, Cloughesy T, Chen W, Satyamurthy N, Czernin J, Phelps ME, Huang SC. Discriminant analysis of ¹⁸F-fluorothymidine kinetic parameters to predict survival in patients with recurrent high-grade glioma. Clin Cancer Res 2011; 17:6553-62. [PMID: 21868765 DOI: 10.1158/1078-0432.ccr-10-3290] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE The primary objective of this study was to investigate whether changes in 3'-deoxy-3'-[¹⁸F]fluorothymidine (¹⁸F-FLT) kinetic parameters, taken early after the start of therapy, could predict overall survival (OS) and progression-free survival (PFS) in patients with recurrent malignant glioma undergoing treatment with bevacizumab and irinotecan. EXPERIMENTAL DESIGN High-grade recurrent brain tumors were investigated in 18 patients (8 male and 10 female), ages 26 to 76 years. Each had 3 dynamic positron emission tomography (PET) studies as follows: at baseline and after 2 and 6 weeks from the start of treatment, ¹⁸F-FLT (2.0 MBq/kg) was injected intravenously, and dynamic PET images were acquired for 1 hour. Factor analysis generated factor images from which blood and tumor uptake curves were derived. A three-compartment, two-tissue model was applied to estimate tumor ¹⁸F-FLT kinetic rate constants using a metabolite- and partial volume-corrected input function. Different combinations of predictor variables were exhaustively searched in a discriminant function to accurately classify patients into their known OS and PFS groups. A leave-one-out cross-validation technique was used to assess the generalizability of the model predictions. RESULTS In this study population, changes in single parameters such as standardized uptake value or influx rate constant did not accurately classify patients into their respective OS groups (<1 and ≥ 1 year; hit ratios ≤ 78%). However, changes in a set of ¹⁸F-FLT kinetic parameters could perfectly separate these two groups of patients (hit ratio = 100%) and were also able to correctly classify patients into their respective PFS groups (<100 and ≥ 100 days; hit ratio = 88%). CONCLUSIONS Discriminant analysis using changes in ¹⁸F-FLT kinetic parameters early during treatment seems to be a powerful method for evaluating the efficacy of therapeutic regimens.
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Affiliation(s)
- Mirwais Wardak
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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Brockenbrough JS, Souquet T, Morihara JK, Stern JE, Hawes SE, Rasey JS, Leblond A, Wiens LW, Feng Q, Grierson J, Vesselle H. Tumor 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) uptake by PET correlates with thymidine kinase 1 expression: static and kinetic analysis of (18)F-FLT PET studies in lung tumors. J Nucl Med 2011; 52:1181-8. [PMID: 21764789 DOI: 10.2967/jnumed.111.089482] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED We report the first, to our knowledge, findings describing the relationships between both static and dynamic analysis parameters of 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) PET and the expression of the proliferation marker Ki-67, and the protein expression and enzymatic activity of thymidine kinase-1 (TK1) in surgically resected lung lesions. METHODS Static and dynamic analyses (4 rate constants and 2 compartments) of (18)F-FLT PET images were performed in a cohort of 25 prospectively accrued, clinically suspected lung cancer patients before surgical resection (1 lesion was found to be benign after surgery). The maximal and overall averaged expression of Ki-67 and TK1 were determined by semiquantitative analysis of immunohistochemical staining. TK1 enzymatic activity was determined by in vitro assay of extracts prepared from flash-frozen samples of the same tumors. RESULTS Static (18)F-FLT uptake (partial-volume-corrected maximum-pixel standardized uptake value from 60- to 90-min summed dynamic data) was significantly correlated with the overall (ρ = 0.57, P = 0.006) and maximal (ρ = 0.69, P < 0.001) immunohistochemical expressions of Ki-67 and TK1 (overall expression: ρ = 0.65, P = 0.001; maximal expression: ρ = 0.68, P < 0.001) but not with TK1 enzymatic activity (ρ = 0.34, P = 0.146). TK1 activity was significantly correlated with TK1 protein expression only when immunohistochemistry was scored for maximal expression (ρ = 0.52, P = 0.029). Dynamic analysis of (18)F-FLT PET revealed correlations between the flux constant (K(FLT)) and both overall (ρ = 0.53, P = 0.014) and maximal (ρ = 0.50, P = 0.020) TK1 protein expression. K(FLT) was also associated with both overall (ρ = 0.59, P = 0.005) and maximal (ρ = 0.63, P = 0.002) Ki-67 expression. We observed no significant correlations between TK1 enzyme activity and K(FLT). In addition, no significant relationships were found between TK1 expression, TK1 activity, or Ki-67 expression and any of the compartmental rate constants. CONCLUSION The absence of observable correlations of the imaging parameters with TK1 activity suggests that (18)F-FLT uptake and retention within cells may be complicated by a variety of still undetermined factors in addition to TK1 enzymatic activity.
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Affiliation(s)
- J Scott Brockenbrough
- Division of Nuclear Medicine, Department of Radiology, University of Washington School of Medicine, Seattle, WA 98195-7115, USA
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Plotnik DA, McLaughlin LJ, Chan J, Redmayne-Titley JN, Schwartz JL. The role of nucleoside/nucleotide transport and metabolism in the uptake and retention of 3'-fluoro-3'-deoxythymidine in human B-lymphoblast cells. Nucl Med Biol 2011; 38:979-86. [PMID: 21982569 DOI: 10.1016/j.nucmedbio.2011.03.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 03/13/2011] [Accepted: 03/26/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Recent studies in the human adenocarcinoma cell line A549 have identified cell growth-dependent equilibrative nucleoside transporter-1 (hENT1) as a modifier of 3'-fluoro-3'-deoxythymidine (FLT) uptake and retention. In the present study, we used the ability to isolate human lymphoblastoid clones deficient in thymidine kinase 1 (TK1) to study how metabolism and nucleoside transport influence FLT uptake and retention. METHODS Transport and metabolism of FLT were measured in the human lymphoblastoid cell line TK6 and in eight clones isolated from TK6. Four clones were TK1-proficient, while four were TK1-deficient. Both influx and efflux of FLT were measured under conditions where concentrative and equilibrative transport could be distinguished. RESULTS Sodium-dependent concentrative FLT transport dominated over equilibrative transport mechanisms and while inhibition of hENT1 reduced FLT uptake, there were no correlations between clonal variations in hENT1 levels and FLT uptake. There was an absolute requirement of TK1 for concentration of FLT in TK6 cells. FLT uptake reached a peak after 60 min of incubation with FLT after which intracellular levels of FLT and FLT metabolites declined. Efflux was rapid and was associated with reductions in FLT and each of its metabolites. Both FLT and FLT-monophosphate were found in the efflux buffer. CONCLUSIONS Initial rates of FLT uptake were a function of both concentrative and equilibrative transporters. TK1 activity was an absolute requirement for the accumulation of FLT. Retention was dependent on nucleoside/nucleotide efflux and retrograde metabolism of FLT nucleotides.
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Affiliation(s)
- David A Plotnik
- Department of Radiation Oncology, University of Washington, Box 356069, Seattle, WA 98195, USA
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Plotnik DA, Emerick LE, Krohn KA, Unadkat JD, Schwartz JL. Different modes of transport for 3H-thymidine, 3H-FLT, and 3H-FMAU in proliferating and nonproliferating human tumor cells. J Nucl Med 2010; 51:1464-71. [PMID: 20720049 DOI: 10.2967/jnumed.110.076794] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The basis for the use of nucleoside tracers in PET is that activity of the cell-growth-dependent enzyme thymidine kinase 1 is the rate-limiting factor driving tracer retention in tumors. Recent publications suggest that nucleoside transporters might influence uptake and thereby affect the tracer signal in vivo. Understanding transport mechanisms for different nucleoside PET tracers is important for evaluating clinical results. This study examined the relative role of different nucleoside transport mechanisms in uptake and retention of [methyl-(3)H]-3'-deoxy-3'-fluorothymidine ((3)H-FLT), [methyl-(3)H]-thymidine ((3)H-thymidine), and (3)H-1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)-5-methyluracil ((3)H-FMAU). METHODS Transport of (3)H-FLT, (3)H-thymidine, and (3)H-FMAU was examined in a single human adenocarcinoma cell line, A549, under both nongrowth and exponential-growth conditions. RESULTS (3)H-Thymidine transport was dominated by human equilibrative nucleoside transporter 1 (hENT1) under both growth conditions. (3)H-FLT was also transported by hENT1, but passive diffusion dominated its transport. (3)H-FMAU transport was dominated by human equilibrative nucleoside transporter 2. Cell membrane levels of hENT1 increased in cells under exponential growth, and this increase was associated with a more rapid rate of uptake for both (3)H-thymidine and (3)H-FLT. (3)H-FMAU transport was not affected by changes in growth conditions. All 3 tracers concentrated in the plateau phase, nonproliferating cells at levels many-fold greater than their concentration in buffer, in part because of low levels of nucleoside metabolism, which inhibited tracer efflux. CONCLUSION Transport mechanisms are not the same for (3)H-thymidine, (3)H-FLT, and (3)H-FMAU. Levels of hENT1, an important transporter of (3)H-FLT and (3)H-thymidine, increase as proliferating cells enter the cell cycle.
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Affiliation(s)
- David A Plotnik
- Department of Radiation Oncology, University of Washington, Seattle, Washington 98195, USA
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Paproski RJ, Wuest M, Jans HS, Graham K, Gati WP, McQuarrie S, McEwan A, Mercer J, Young JD, Cass CE. Biodistribution and Uptake of 3′-Deoxy-3′-Fluorothymidine in ENT1-Knockout Mice and in an ENT1-Knockdown Tumor Model. J Nucl Med 2010; 51:1447-55. [DOI: 10.2967/jnumed.110.076356] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Robins MJ, Peng Y, Damaraju VL, Mowles D, Barron G, Tackaberry T, Young JD, Cass CE. Improved Syntheses of 5′-S-(2-Aminoethyl)-6-N-(4-nitrobenzyl)-5′-thioadenosine (SAENTA), Analogues, and Fluorescent Probe Conjugates: Analysis of Cell-Surface Human Equilibrative Nucleoside Transporter 1 (hENT1) Levels for Prediction of the Antitumor Efficacy of Gemcitabine. J Med Chem 2010; 53:6040-53. [DOI: 10.1021/jm100432w] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Morris J. Robins
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602-5700
| | - Yunshan Peng
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602-5700
| | - Vijaya L. Damaraju
- Departments of Oncology and Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 1Z2
| | - Delores Mowles
- Departments of Oncology and Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 1Z2
| | - Geraldine Barron
- Departments of Oncology and Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 1Z2
| | - Tracey Tackaberry
- Departments of Oncology and Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 1Z2
| | - James D. Young
- Departments of Oncology and Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 1Z2
| | - Carol E. Cass
- Departments of Oncology and Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 1Z2
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Paproski RJ, Young JD, Cass CE. Predicting gemcitabine transport and toxicity in human pancreatic cancer cell lines with the positron emission tomography tracer 3'-deoxy-3'-fluorothymidine. Biochem Pharmacol 2010; 79:587-95. [PMID: 19788890 DOI: 10.1016/j.bcp.2009.09.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/22/2009] [Accepted: 09/23/2009] [Indexed: 12/14/2022]
Abstract
The abundance of human equilibrative nucleoside transporter 1 (hENT1) has recently been shown to be a predictive marker of benefit from gemcitabine therapy in patients with pancreatic cancer. Since hENT1 is also important for the uptake of positron emission tomography (PET) tracer 3'-deoxy-3'-fluorothymidine (FLT) in various cultured human cell lines, this study was undertaken to determine if FLT uptake predicts gemcitabine uptake and/or toxicity in a panel of human pancreatic cancer cell lines (Capan-2, AsPC-1, BxPC-3, PL45, MIA PaCa-2, and PANC-1). Capan-2 cells displayed the lowest levels of (1) extracellular nitrobenzylmercaptopurine ribonucleoside (NBMPR) binding, which represents cell-surface hENT1, (2) FLT and gemcitabine uptake during short (1-45s) and prolonged (1h) periods, and (3) gemcitabine sensitivity. Exposure to NBMPR (inhibits only hENT1) or dilazep (inhibits hENT1 and hENT2) reduced FLT and gemcitabine uptake and gemcitabine sensitivity, with dilazep having greater effects than NBMPR. Gemcitabine permeation was almost completely mediated, primarily by hENT1 and to a lesser extent by hENT2, whereas FLT permeation included a substantial component of passive diffusion. In five of six cell lines, correlations were observed between (1) FLT and gemcitabine initial rates of uptake, (2) gemcitabine uptake and gemcitabine toxicity, (3) FLT uptake and gemcitabine toxicity, and (4) ribonucleotide reductase subunit M1 expression and gemcitabine toxicity. FLT and gemcitabine uptake were comparable for predicting gemcitabine toxicity in the tested pancreatic cancer cell lines suggesting that FLT PET may provide clinically useful information about tumor gemcitabine transport capacity and sensitivity.
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Affiliation(s)
- Robert J Paproski
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Ave., Edmonton, Alberta, Canada.
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